U.S. patent application number 15/173427 was filed with the patent office on 2016-12-29 for microorganisms for the production of 1,4-butanediol, 4-hydroxybutanal, 4-hydroxybutyryl-coa, putrescine and related compounds, and methods related thereto.
The applicant listed for this patent is Genomatica, Inc.. Invention is credited to Anthony P. BURGARD, Robert HASELBECK, Wei NIU, John D. TRAWICK.
Application Number | 20160376614 15/173427 |
Document ID | / |
Family ID | 43876524 |
Filed Date | 2016-12-29 |
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United States Patent
Application |
20160376614 |
Kind Code |
A1 |
HASELBECK; Robert ; et
al. |
December 29, 2016 |
MICROORGANISMS FOR THE PRODUCTION OF 1,4-BUTANEDIOL,
4-HYDROXYBUTANAL, 4-HYDROXYBUTYRYL-COA, PUTRESCINE AND RELATED
COMPOUNDS, AND METHODS RELATED THERETO
Abstract
The invention provides non-naturally occurring microbial
organisms comprising a 1,4-butanediol (BDO), 4-hydroxybutyryl-CoA,
4-hydroxybutanal or putrescine pathway comprising at least one
exogenous nucleic acid encoding a BDO, 4-hydroxybutyryl-CoA,
4-hydroxybutanal or putrescine pathway enzyme expressed in a
sufficient amount to produce BDO, 4-hydroxybutyryl-CoA,
4-hydroxybutanal or putrescine and further optimized for expression
of BDO. The invention additionally provides methods of using such
microbial organisms to produce BDO, 4-hydroxybutyryl-CoA,
4-hydroxybutanal or putrescine.
Inventors: |
HASELBECK; Robert; (San
Diego, CA) ; TRAWICK; John D.; (La Mesa, CA) ;
NIU; Wei; (Lincoln, NE) ; BURGARD; Anthony P.;
(Bellefonte, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Genomatica, Inc. |
San Diego |
CA |
US |
|
|
Family ID: |
43876524 |
Appl. No.: |
15/173427 |
Filed: |
June 3, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13737866 |
Jan 9, 2013 |
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15173427 |
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13109732 |
May 17, 2011 |
8377667 |
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13737866 |
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12904130 |
Oct 13, 2010 |
8377666 |
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13109732 |
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61251287 |
Oct 13, 2009 |
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Current U.S.
Class: |
435/147 |
Current CPC
Class: |
C12P 13/001 20130101;
C12P 7/42 20130101; C12P 7/24 20130101; C12P 19/40 20130101; C12P
7/18 20130101 |
International
Class: |
C12P 7/18 20060101
C12P007/18; C12P 7/24 20060101 C12P007/24; C12P 7/42 20060101
C12P007/42; C12P 13/00 20060101 C12P013/00 |
Claims
1. A non-naturally occurring microbial organism, comprising a
4-hydroxybutanal pathway comprising at least one exogenous nucleic
acid encoding a 4-hydroxybutanal pathway enzyme expressed in a
sufficient amount to produce 4-hydroxybutanal, said
4-hydroxybutanal pathway comprising: succinyl-CoA reductase
(aldehyde forming); 4-hydroxybutyrate dehydrogenase; and
4-hydroxybutyrate reductase; alpha-ketoglutarate decarboxylase;
4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase;
succinate reductase; 4-hydroxybutyrate dehydrogenase, and
4-hydroxybutyrate reductase; alpha-ketoglutarate decarboxylase, or
glutamate dehydrogenase or glutamate transaminase and glutamate
decarboxylase and 4-aminobutyrate dehydrogenase or 4-aminobutyrate
transaminase; 4-hydroxybutyrate dehydrogenase; and
4-hydroxybutyrate reductase; or alpha-ketoglutarate reductase;
5-hydroxy-2-oxopentanoate dehydrogenase; and
5-hydroxy-2-oxopentanoate decarboxylase; succinyl-CoA reductase
(aldehyde forming); 4-hydroxybutyrate dehydrogenase;
4-hydroxybutyryl-CoA transferase or 4-hydroxybutyryl-CoA hydrolase
or 4-hydroxybutyryl-CoA synthetase; and 4-hydroxybutyryl-CoA
reductase (aldehyde forming); succinyl-CoA reductase (aldehyde
forming); 4-hydroxybutyrate dehydrogenase; 4-hydroxybutyrate
kinase; phosphotrans-4-hydroxybutyrylase; and 4-hydroxybutyryl-CoA
reductase (aldehyde forming); or succinyl-CoA reductase (aldehyde
forming); 4-hydroxybutyrate dehydrogenase; 4-hydroxybutyrate
kinase; and 4-hydroxybutyryl-phosphate reductase.
2. The non-naturally occurring microbial organism of claim 1,
wherein said microbial organism comprises three exogenous nucleic
acids encoding succinyl-CoA reductase (aldehyde forming);
4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate
reductase.
3. The non-naturally occurring microbial organism of claim 1,
wherein said at least one exogenous nucleic acid is a heterologous
nucleic acid.
4. A method for producing 4-hydroxybutanal, comprising culturing
the non-naturally occurring microbial organism of claim 1 under
conditions and for a sufficient period of time to produce
4-hydroxybutanal.
5. The method of claim 4, wherein said non-naturally occurring
microbial organism is in a substantially anaerobic culture
medium.
6. The non-naturally occurring microbial organism of claim 1, said
4-hydroxybutanal pathway comprising alpha-ketoglutarate
decarboxylase; 4-hydroxybutyrate dehydrogenase; and
4-hydroxybutyrate reductase.
7. The non-naturally occurring microbial organism of claim 6,
wherein said microbial organism comprises three exogenous nucleic
acids encoding alpha-ketoglutarate decarboxylase; 4-hydroxybutyrate
dehydrogenase; and 4-hydroxybutyrate reductase.
8. The non-naturally occurring microbial organism of claim 6,
wherein said at least one exogenous nucleic acid is a heterologous
nucleic acid.
9-10. (canceled)
11. The non-naturally occurring microbial organism of claim 1, said
4-hydroxybutanal pathway comprising succinate reductase;
4-hydroxybutyrate dehydrogenase, and 4-hydroxybutyrate
reductase.
12. The non-naturally occurring microbial organism of claim 11,
wherein said microbial organism comprises three exogenous nucleic
acids encoding succinate reductase; 4-hydroxybutyrate
dehydrogenase, and 4-hydroxybutyrate reductase.
13. The non-naturally occurring microbial organism of claim 11,
wherein said at least one exogenous nucleic acid is a heterologous
nucleic acid.
14-15. (canceled)
16. The non-naturally occurring microbial organism of claim 1, said
4-hydroxybutanal pathway comprising alpha-ketoglutarate
decarboxylase, or glutamate dehydrogenase or glutamate transaminase
and glutamate decarboxylase and 4-aminobutyrate dehydrogenase or
4-aminobutyrate transaminase; 4-hydroxybutyrate dehydrogenase; and
4-hydroxybutyrate reductase.
17. The non-naturally occurring microbial organism of claim 1, said
4-hydroxybutanal pathway comprising alpha-ketoglutarate reductase;
5-hydroxy-2-oxopentanoate dehydrogenase; and
5-hydroxy-2-oxopentanoate decarboxylase.
18. A non-naturally occurring microbial organism, comprising a
microbial organism having a putrescine pathway comprising at least
one exogenous nucleic acid encoding a putrescine pathway enzyme
expressed in a sufficient amount to produce putrescine, said
putrescine pathway comprising: succinate reductase; 4-aminobutyrate
dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate
reductase; and putrescine dehydrogenase or putrescine transaminase;
alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or
4-aminobutyrate transaminase; 4-aminobutyrate reductase; and
putrescine dehydrogenase or putrescine transaminase; glutamate
dehydrogenase or glutamate transaminase; glutamate decarboxylase;
4-aminobutyrate reductase; and putrescine dehydrogenase or
putrescine transaminase; or alpha-ketoglutarate reductase;
5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate
transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine
dehydrogenase or putrescine transaminase.
19. The non-naturally occurring microbial organism of claim 18,
said putrescine pathway comprising alpha-ketoglutarate
decarboxylase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate
transaminase; 4-aminobutyrate reductase; and putrescine
dehydrogenase or putrescine transaminase.
20. The non-naturally occurring microbial organism of claim 18,
said putrescine pathway comprising glutamate dehydrogenase or
glutamate transaminase; glutamate decarboxylase; 4-aminobutyrate
reductase; and putrescine dehydrogenase or putrescine
transaminase.
21. The non-naturally occurring microbial organism of claim 18,
said putrescine pathway comprising alpha-ketoglutarate reductase;
5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate
transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine
dehydrogenase or putrescine transaminase.
Description
[0001] This application is a continuation of application Ser. No.
13/737,866, filed Jan. 9, 2013, which is a continuation of
application Ser. No. 13/109,732, filed May 17, 2011, now U.S. Pat.
No. 8,377,667, which is a continuation of application Ser. No.
12/904,130, filed Oct. 13, 2010, now U.S. Pat. No. 8,377,666, which
claims the benefit of priority of U.S. Provisional Application No.
61/251,287, filed Oct. 13, 2009, each of which the entire contents
are incorporated herein by reference.
[0002] Incorporated herein by reference is the Sequence Listing
being submitted via EFS-Web as an ASCII text file named
12956-399-999_Sequence_Listing.txt, created Jun. 2, 2016, and being
168,480 bytes in size.
BACKGROUND OF THE INVENTION
[0003] This invention relates generally to in silico design of
organisms and engineering of organisms, more particularly to
organisms having 1,4-butanediol, 4-hydroxybutyryl-CoA,
4-hydroxybutanal or putrescine biosynthesis capability.
[0004] The compound 4-hydroxybutanoic acid (4-hydroxybutanoate,
4-hydroxybutyrate, 4-HB) is a 4-carbon carboxylic acid that has
industrial potential as a building block for various commodity and
specialty chemicals. In particular, 4-HB has the potential to serve
as a new entry point into the 1,4-butanediol family of chemicals,
which includes solvents, resins, polymer precursors, and specialty
chemicals. 1,4-Butanediol (BDO) is a polymer intermediate and
industrial solvent with a global market of about 3 billion lb/year.
BDO is currently produced from petrochemical precursors, primarily
acetylene, maleic anhydride, and propylene oxide.
[0005] For example, acetylene is reacted with 2 molecules of
formaldehyde in the Reppe synthesis reaction (Kroschwitz and Grant,
Encyclopedia of Chem. Tech., John Wiley and Sons, Inc., New York
(1999)), followed by catalytic hydrogenation to form
1,4-butanediol. It has been estimated that 90% of the acetylene
produced in the U.S. is consumed for butanediol production.
Alternatively, it can be formed by esterification and catalytic
hydrogenation of maleic anhydride, which is derived from butane.
Downstream, butanediol can be further transformed; for example, by
oxidation to .gamma.-butyrolactone, which can be further converted
to pyrrolidone and N-methyl-pyrrolidone, or hydrogenolysis to
tetrahydrofuran. These compounds have varied uses as polymer
intermediates, solvents, and additives, and have a combined market
of nearly 2 billion lb/year.
[0006] It is desirable to develop a method for production of these
chemicals by alternative means that not only substitute renewable
for petroleum-based feedstocks, and also use less energy- and
capital-intensive processes. The Department of Energy has proposed
1,4-diacids, and particularly succinic acid, as key
biologically-produced intermediates for the manufacture of the
butanediol family of products (DOE Report, "Top Value-Added
Chemicals from Biomass", 2004). However, succinic acid is costly to
isolate and purify and requires high temperatures and pressures for
catalytic reduction to butanediol.
[0007] Thus, there exists a need for alternative means for
effectively producing commercial quantities of 1,4-butanediol and
its chemical precursors. The present invention satisfies this need
and provides related advantages as well.
SUMMARY OF INVENTION
[0008] The invention provides non-naturally occurring microbial
organisms containing a 1,4-butanediol (BDO), 4-hydroxybutanal
(4-HBal), 4-hydroxybutyryl-CoA (4-HBCoA) and/or putrescine pathway
comprising at least one exogenous nucleic acid encoding a BDO,
4-HBal and/or putrescine pathway enzyme expressed in a sufficient
amount to produce BDO, 4-HBal, 4-HBCoA and/or putrescine. The
microbial organisms can be further optimized for expression of BDO,
4-HBal, 4-HBCoA and/or putrescine. The invention additionally
provides methods of using such microbial organisms to produce BDO,
4-HBal, 4-HBCoA and/or putrescine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic diagram showing biochemical pathways
to 4-hydroxybutyurate (4-HB) and to 1,4-butanediol production. The
first 5 steps are endogenous to E. coli, while the remainder can be
expressed heterologously. Enzymes catalyzing the biosynthetic
reactions are: (1) succinyl-CoA synthetase; (2) CoA-independent
succinic semialdehyde dehydrogenase; (3) .alpha.-ketoglutarate
dehydrogenase; (4) glutamate:succinate semialdehyde transaminase;
(5) glutamate decarboxylase; (6) CoA-dependent succinic
semialdehyde dehydrogenase; (7) 4-hydroxybutanoate dehydrogenase;
(8) .alpha.-ketoglutarate decarboxylase; (9) 4-hydroxybutyryl
CoA:acetyl-CoA transferase; (10) butyrate kinase; (11)
phosphotransbutyrylase; (12) aldehyde dehydrogenase; (13) alcohol
dehydrogenase.
[0010] FIG. 2 is a schematic diagram showing homoserine
biosynthesis in E. coli.
[0011] FIGS. 3A-3C show the production of 4-HB in glucose minimal
medium using E. coli strains harboring plasmids expressing various
combinations of 4-HB pathway genes. FIG. 3A: 4-HB concentration in
culture broth; FIG. 3B: succinate concentration in culture broth;
FIG. 3C: culture OD, measured at 600 nm. Clusters of bars represent
the 24 hour, 48 hour, and 72 hour (if measured) timepoints. The
codes along the x-axis indicate the strain/plasmid combination
used. The first index refers to the host strain: 1, MG1655
lacI.sup.Q; 2, MG1655 .DELTA.gabD lacI.sup.Q; 3, MG1655 .DELTA.gabD
.DELTA.aldA lacI.sup.Q. The second index refers to the plasmid
combination used: 1, pZE13-0004-0035 and pZA33-0036; 2,
pZE13-0004-0035 and pZA33-0010n; 3, pZE13-0004-0008 and pZA33-0036;
4, pZE13-0004-0008 and pZA33-0010n; 5, Control vectors pZE13 and
pZA33.
[0012] FIG. 4 shows the production of 4-HB from glucose in E. coli
strains expressing .alpha.-ketoglutarate decarboxylase from
Mycobacterium tuberculosis. Strains 1-3 contain pZE13-0032 and
pZA33-0036. Strain 4 expresses only the empty vectors pZE13 and
pZA33. Host strains are as follows: 1 and 4, MG1655 lacI.sup.Q; 2,
MG1655 .DELTA.gabD lacI.sup.Q; 3, MG1655 .DELTA.gabD .DELTA.aldA
lacI.sup.Q. The bars refer to concentration at 24 and 48 hours.
[0013] FIG. 5 shows the production of BDO from 10 mM 4-HB in
recombinant E. coli strains. Numbered positions correspond to
experiments with MG1655 lacI.sup.Q containing pZA33-0024,
expressing cat2 from P. gingivalis, and the following genes
expressed on pZE13: 1, none (control); 2, 0002; 3, 0003; 4, 0003n;
5, 0011; 6, 0013; 7, 0023; 8, 0025; 9, 0008n; 10, 0035. Gene
numbers are defined in Table 6. For each position, the bars refer
to aerobic, microaerobic, and anaerobic conditions, respectively.
Microaerobic conditions were created by sealing the culture tubes
but not evacuating them.
[0014] FIGS. 6A-6H shows the mass spectrum of 4-HB and BDO produced
by MG1655 lacI.sup.Q pZE13-0004-0035-0002 pZA33-0034-0036 grown in
M9 minimal medium supplemented with 4 g/L unlabeled glucose (FIGS.
6A, 6C, 6E and 6G) uniformly labeled .sup.13C-glucose (FIGS. 6B,
6D, 6F and 6H). FIGS. 6A and 6B, mass 116 characteristic fragment
of derivatized BDO, containing 2 carbon atoms; FIGS. 6C and 6D,
mass 177 characteristic fragment of derivatized BDO, containing 1
carbon atom; FIGS. 6E and 6F, mass 117 characteristic fragment of
derivatized 4-HB, containing 2 carbon atoms; FIGS. 6G and 6H, mass
233 characteristic fragment of derivatized 4-HB, containing 4
carbon atoms.
[0015] FIG. 7 is a schematic process flow diagram of bioprocesses
for the production of .gamma.-butyrolactone. Panel (a) illustrates
fed-batch fermentation with batch separation and panel (b)
illustrates fed-batch fermentation with continuous separation.
[0016] FIGS. 8A and 8B show exemplary 1,4-butanediol (BDO)
pathways. FIG. 8A shows BDO pathways from succinyl-CoA. FIG. 8B
shows BDO pathways from alpha-ketoglutarate.
[0017] FIGS. 9A-9C show exemplary BDO pathways. FIGS. 9A and 9B
show pathways from 4-aminobutyrate. FIG. 9C shows a pathway from
acetoactyl-CoA to 4-aminobutyrate.
[0018] FIG. 10 shows exemplary BDO pathways from
alpha-ketoglutarate.
[0019] FIG. 11 shows exemplary BDO pathways from glutamate.
[0020] FIG. 12 shows exemplary BDO pathways from
acetoacetyl-CoA.
[0021] FIG. 13 shows exemplary BDO pathways from homoserine.
[0022] FIGS. 14A-14C show the nucleotide and amino acid sequences
of E. coli succinyl-CoA synthetase. FIG. 14A shows the nucleotide
sequence (SEQ ID NO:46) of the E. coli sucCD operon. FIGS. 14B (SEQ
ID NO:47) and 14C (SEQ ID NO:48) show the amino acid sequences of
the succinyl-CoA synthetase subunits encoded by the sucCD
operon.
[0023] FIGS. 15A and 15B show the nucleotide and amino acid
sequences of Mycobacterium bovis alpha-ketoglutarate decarboxylase.
FIG. 15A shows the nucleotide sequence (SEQ ID NO:49) of
Mycobacterium bovis sucA gene. FIG. 15B shows the amino acid
sequence (SEQ ID NO:50) of M. bovis alpha-ketoglutarate
decarboxylase.
[0024] FIG. 16 shows biosynthesis in E. coli of 4-hydroxybutyrate
from glucose in minimal medium via alpha-ketoglutarate under
anaerobic (microaerobic) conditions. The host strain is ECKh-401.
The experiments are labeled based on the upstream pathway genes
present on the plasmid pZA33 as follows: 1) 4hbd-sucA; 2)
sucCD-sucD-4hbd; 3) sucCD-sucD-4hbd-sucA.
[0025] FIG. 17 shows biosynthesis in E. coli of 4-hydroxybutyrate
from glucose in minimal medium via succinate and
alpha-ketoglutarate. The host strain is wild-type MG1655. The
experiments are labeled based on the genes present on the plasmids
pZE13 and pZA33 as follows: 1) empty control vectors 2) empty
pZE13, pZA33-4hbd; 3) pZE13-sucA, pZA33-4hbd.
[0026] FIG. 18A shows the nucleotide sequence (SEQ ID NO:51) of
CoA-dependent succinate semialdehyde dehydrogenase (sucD) from
Porphyromonas gingivalis, and FIG. 18B shows the encoded amino acid
sequence (SEQ ID NO:52).
[0027] FIG. 19A shows the nucleotide sequence (SEQ ID NO:53) of
4-hydroxybutyrate dehydrogenase (4hbd) from Porphymonas gingivalis,
and FIG. 19B shows the encoded amino acid sequence (SEQ ID
NO:54).
[0028] FIG. 20A shows the nucleotide sequence (SEQ ID NO:55) of
4-hydroxybutyrate CoA transferase (cat2) from Porphyromonas
gingivalis, and FIG. 20B shows the encoded amino acid sequence (SEQ
ID NO:56).
[0029] FIG. 21A shows the nucleotide sequence (SEQ ID NO:57) of
phosphotransbutyrylase (ptb) from Clostridium acetobutylicum, and
FIG. 21B shows the encoded amino acid sequence (SEQ ID NO:58).
[0030] FIG. 22A shows the nucleotide sequence (SEQ ID NO:59) of
butyrate kinase (buk1) from Clostridium acetobutylicum, and FIG.
22B shows the encoded amino acid sequence (SEQ ID NO:60).
[0031] FIGS. 23A-23D show alternative nucleotide sequences for C.
acetobutylicum 020 (phosphtransbutyrylase) with altered codons for
more prevalent E. coli codons relative to the C. acetobutylicum
native sequence. FIGS. 23A-23D (020A-020D, SEQ ID NOS:61-64,
respectively) contain sequences with increasing numbers of rare E.
coli codons replaced by more prevalent codons
(A<B<C<D).
[0032] FIGS. 24A-24D show alternative nucleotide sequences for C.
acetobuytlicum 021 (butyrate kinase) with altered codons for more
prevalent E. coli codons relative to the C. acetobutylicum native
sequence. FIGS. 24A-24D (021A-021B, SEQ ID NOS:65-68, respectively)
contain sequences with increasing numbers of rare E. coli codons
replaced by more prevalent codons (A<B<C<D).
[0033] FIGS. 25A and 25B show improved expression of butyrate
kinase (BK) and phosphotransbutyrylase (PTB) with optimized codons
for expression in E. coli. FIG. 25A shows sodium dodecyl sulfate
polyacrylamide gel electrophoresis (SDS-PAGE) stained for proteins
with Coomassie blue; lane 1, control vector with no insert; lane 2,
expression of C. acetobutylicum native sequences in E. coli; lane
3, expression of 020B-021B codon optimized PTB-BK; lane 4,
expression of 020C-021C codon optimized PTB-BK. The positions of BK
and PTB are shown. FIG. 25B shows the BK and PTB activities of
native C. acetobutylicum sequence (2021n) compared to codon
optimized 020B-021B (2021B) and 020C-021C (2021C).
[0034] FIG. 26 shows production of BDO and gamma-butyrylactone
(GBL) in various strains expressing BDO producing enzymes: Cat2
(034); 2021n; 2021B; 2021C.
[0035] FIG. 27A shows the nucleotide sequence (SEQ ID NO:69) of the
native Clostridium biejerinckii ald gene (025n), and FIG. 27B shows
the encoded amino acid sequence (SEQ ID NO:70).
[0036] FIGS. 28A-28D show alternative gene sequences for the
Clostridium beijerinckii ald gene (025A-025D, SEQ ID NOS:71-74,
respectively), in which increasing numbers of rare codons are
replaced by more prevalent codons (A<B<C<D).
[0037] FIG. 29 shows expression of native C. beijerinckii ald gene
and codon optimized variants; no ins (control with no insert),
025n, 025A, 025B, 025C, 025D.
[0038] FIGS. 30A and 30B show BDO or BDO and ethanol production in
various strains. FIG. 30A shows BDO production in strains
containing the native C. beijerinckii ald gene (025n) or variants
with optimized codons for expression in E. coli (025A-025D). FIG.
30B shows production of ethanol and BDO in strains expressing the
C. acetobutylicum AdhE2 enzyme (002C) compared to the codon
optimized variant 025B. The third set shows expression of P.
gingivalis sucD (035). In all cases, P. gingivalis Cat2 (034) is
also expressed.
[0039] FIG. 31A shows the nucleotide sequence (SEQ ID NO:75) of the
adh1 gene from Geobacillus thermoglucosidasius, and FIG. 31B shows
the encoded amino acid sequence (SEQ ID NO:76).
[0040] FIG. 32A shows the expression of the Geobacillus
thermoglucosidasius adh1 gene in E. coli. Either whole cell lysates
or supernatants were analyzed by SDS-PAGE and stained with
Coomassie blue for plasmid with no insert, plasmid with 083
(Geotrichum capitatum N-benzyl-3-pyrrolidinol dehydrogenase) and
plasmid with 084 (Geobacillus thermoglucosidasius adh1) inserts.
FIG. 32B shows the activity of 084 with butyraldehyde (diamonds) or
4-hydroxybutyraldehyde (squares) as substrates.
[0041] FIG. 33 shows the production of BDO in various strains:
plasmid with no insert; 025B, 025B-026n; 025B-026A; 025B-026B;
025B-026C; 025B-050; 025B-052; 025B-053; 025B-055; 025B-057;
025B-058; 025B-071; 025B-083; 025B-084; PTSlacO-025B;
PTSlacO-025B-026n.
[0042] FIG. 34 shows a plasmid map for the vector pRE118-V2.
[0043] FIG. 35 shows the sequence (SEQ ID NO:77) of the ECKh-138
region encompassing the aceF and lpdA genes. The K. pneumonia lpdA
gene is underlined, and the codon changed in the Glu354Lys mutant
shaded.
[0044] FIG. 36 shows the protein sequence comparison of the native
E. coli lpdA (SEQ ID NO:78) and the mutant K. pneumonia lpdA (SEQ
ID NO:79).
[0045] FIG. 37 shows 4-hydroxybutyrate (left bars) and BDO (right
bars) production in the strains AB3, MG1655 .DELTA.ldhA and
ECKh-138. All strains expressed E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd on the medium copy plasmid pZA33, and P.
gingivalis Cat2, C. acetobutylicum AdhE2 on the high copy plasmid
pZE13.
[0046] FIG. 38 shows the nucleotide sequence (SEQ ID NO:80) of the
5' end of the aceE gene fused to the pflB-p6 promoter and ribosome
binding site (RBS). The 5' italicized sequence shows the start of
the aroP gene, which is transcribed in the opposite direction from
the pdh operon. The 3' italicized sequence shows the start of the
aceE gene. In upper case: pflB RBS. Underlined: FNR binding site.
In bold: pflB-p6 promoter sequence.
[0047] FIG. 39 shows the nucleotide sequence (SEQ ID NO:81) in the
aceF-lpdA region in the strain ECKh-456.
[0048] FIG. 40 shows the production of 4-hydroxybutyrate, BDO and
pyruvate (left to right bars, respectively) for each of strains
ECKh-439, ECKh-455 and ECKh-456.
[0049] FIG. 41A shows a schematic of the recombination sites for
deletion of the mdh gene. FIG. 41B shows the sequence (nucleotide
sequence, SEQ ID NO:82; amino acid sequence, SEQ ID NO:83) of the
PCR product of the amplification of chloramphenicol resistance gene
(CAT) flanked by FRT sites and homology regions from the mdh gene
from the plasmid pKD3.
[0050] FIG. 42 shows the sequence (SEQ ID NO:84) of the arcA
deleted region in strain ECKh-401.
[0051] FIG. 43 shows the sequence (SEQ ID NO:85) of the region
encompassing a mutated gltA gene of strain ECKh-422.
[0052] FIGS. 44A and 44B show the citrate synthase activity of wild
type gltA gene product and the R163L mutant. The assay was
performed in the absence (diamonds) or presence of 0.4 mM NADH
(squares).
[0053] FIG. 45 shows the 4-hydroxybutyrate (left bars) and BDO
(right bars) production in strains ECKh-401 and ECKh-422, both
expressing genes for the complete BDO pathway on plasmids.
[0054] FIG. 46 shows central metabolic fluxes and associated 95%
confidence intervals from metabolic labeling experiments. Values
are molar fluxes normalized to a glucose uptake rate of 1 mmol/hr.
The result indicates that carbon flux is routed through citrate
synthase in the oxidative direction and that most of the carbon
enters the BDO pathway rather than completing the TCA cycle.
[0055] FIGS. 47A and 47B show extracellular product formation for
strains ECKh-138 and ECKh-422, both expressing the entire BDO
pathway on plasmids. The products measured were acetate (Ace),
pyruvate (Pyr), 4-hydroxybutyrate (4HB), 1,4-butanediol (BDO),
ethanol (EtOH), and other products, which include
gamma-butyrolactone (GBL), succinate, and lactate.
[0056] FIG. 48 shows the sequence (SEQ ID NO:86) of the region
following replacement of PEP carboxylase (ppc) by H. influenzae
phosphoenolpyruvate carboxykinase (pepck). The pepck coding region
is underlined.
[0057] FIG. 49 shows growth of evolved pepCK strains grown in
minimal medium containing 50 mM NaHCO.sub.3.
[0058] FIG. 50 shows product formation in strain ECKh-453
expressing P. gingivalis Cat2 and C. beijerinckii Ald on the
plasmid pZS*13. The products measured were 1,4-butanediol (BDO),
pyruvate, 4-hydroxybutyrate (4HB), acetate, .gamma.-butyrolactone
(GBL) and ethanol.
[0059] FIG. 51 shows BDO production of two strains, ECKh-453 and
ECKh-432. Both contain the plasmid pZS*13 expressing P. gingivalis
Cat2 and C. beijerinckii Ald. The cultures were grown under
microaerobic conditions, with the vessels punctured with 27 or 18
gauge needles, as indicated.
[0060] FIG. 52 shows the nucleotide sequence (SEQ ID NO:87) of the
genomic DNA of strain ECKh-426 in the region of insertion of a
polycistronic DNA fragment containing a promoter, sucCD gene, sucD
gene, 4hbd gene and a terminator sequence.
[0061] FIG. 53 shows the nucleotide sequence (SEQ ID NO:88) of the
chromosomal region of strain ECKh-432 in the region of insertion of
a polycistronic sequence containing a promoter, sucA gene, C.
kluyveri 4hbd gene and a terminator sequence.
[0062] FIG. 54 shows BDO synthesis from glucose in minimal medium
in the ECKh-432 strain having upstream BDO pathway encoding genes
integrated into the chromosome and containing a plasmid harboring
downstream BDO pathway genes.
[0063] FIG. 55 shows a PCR product (SEQ ID NO:89) containing the
non-phosphotransferase (non-PTS) sucrose utilization genes flanked
by regions of homology to the rrnC region.
[0064] FIG. 56 shows a schematic diagram of the integrations site
in the rrnC operon.
[0065] FIG. 57 shows average product concentration, normalized to
culture OD600, after 48 hours of growth of strain ECKh-432 grown on
glucose and strain ECKh-463 grown on sucrose. Both contain the
plasmid pZS*13 expressing P. gingivalis Cat2 and C. beijerinckii
Ald. The data is for 6 replicate cultures of each strain. The
products measured were 1,4-butanediol (BDO), 4-hydroxybutyrate
(4HB), .gamma.-butyrolactone (GBL), pyruvate (PYR) and acetate
(ACE) (left to right bars, respectively).
[0066] FIG. 58 shows exemplary pathways to 1,4-butanediol from
succcinyl-CoA and alpha-ketoglutarate. Abbreviations: A)
Succinyl-CoA reductase (aldehyde forming), B) Alpha-ketoglutarate
decarboxylase, C) 4-Hydroxybutyrate dehydrogenase, D)
4-Hydroxybutyrate reductase, E) 1,4-Butanediol dehydrogenase.
[0067] FIG. 59A shows the nucleotide sequence (SEQ ID NO:90) of
carboxylic acid reductase from Nocardia iowensis (GNM_720), and
FIG. 59B shows the encoded amino acid sequence (SEQ ID NO:91).
[0068] FIG. 60A shows the nucleotide sequence (SEQ ID NO:92) of
phosphpantetheine transferase, which was codon optimized, and FIG.
60B shows the encoded amino acid sequence (SEQ ID NO:93).
[0069] FIG. 61 shows a plasmid map of plasmid pZS*-13S-720
721opt.
[0070] FIGS. 62A and 62B show pathways to 1,4-butanediol from
succinate, succcinyl-CoA, and alpha-ketoglutarate. Abbreviations:
A) Succinyl-CoA reductase (aldehyde forming), B)
Alpha-ketoglutarate decarboxylase, C) 4-Hydroxybutyrate
dehydrogenase, D) 4-Hydroxybutyrate reductase, E) 1,4-Butanediol
dehydrogenase, F) Succinate reductase, G) Succinyl-CoA transferase,
H) Succinyl-CoA hydrolase, I) Succinyl-CoA synthetase (or
Succinyl-CoA ligase), J) Glutamate dehydrogenase, K) Glutamate
transaminase, L) Glutamate decarboxylase, M) 4-aminobutyrate
dehydrogenase, N) 4-aminobutyrate transaminase, O)
4-Hydroxybutyrate kinase, P) Phosphotrans-4-hydroxybutyrylase, Q)
4-Hydroxybutyryl-CoA reductase (aldehyde forming), R)
4-hydroxybutyryl-phosphate reductase, S) Succinyl-CoA reductase
(alcohol forming), T) 4-Hydroxybutyryl-CoA transferase, U)
4-Hydroxybutyryl-CoA hydrolase, V) 4-Hydroxybutyryl-CoA synthetase
(or 4-Hydroxybutyryl-CoA ligase), W) 4-Hydroxybutyryl-CoA reductase
(alcohol forming), X) Alpha-ketoglutarate reductase, Y)
5-Hydroxy-2-oxopentanoate dehydrogenase, Z)
5-Hydroxy-2-oxopentanoate decarboxylase, AA)
5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation).
[0071] FIG. 63 shows pathways to putrescine from succinate,
succcinyl-CoA, and alpha-ketoglutarate. Abbreviations: A)
Succinyl-CoA reductase (aldehyde forming), B) Alpha-ketoglutarate
decarboxylase, C) 4-Aminobutyrate reductase, D) Putrescine
dehydrogenase, E) Putrescine transaminase, F) Succinate reductase,
G) Succinyl-CoA transferase, H) Succinyl-CoA hydrolase, I)
Succinyl-CoA synthetase (or Succinyl-CoA ligase), J) Glutamate
dehydrogenase, K) Glutamate transaminase, L) Glutamate
decarboxylase, M) 4-Aminobutyrate dehydrogenase, N) 4-Aminobutyrate
transaminase, O) Alpha-ketoglutarate reductase, P)
5-Amino-2-oxopentanoate dehydrogenase, Q) 5-Amino-2-oxopentanoate
transaminase, R) 5-Amino-2-oxopentanoate decarboxylase, S)
Ornithine dehydrogenase, T) Ornithine transaminase, U) Ornithine
decarboxylase.
DETAILED DESCRIPTION OF THE INVENTION
[0072] The present invention is directed to the design and
production of cells and organisms having biosynthetic production
capabilities for 4-hydroxybutanoic acid (4-HB),
.gamma.-butyrolactone, 1,4-butanediol (BDO), 4-hydroxybutanal
(4-HBal), 4-hydroxybutyryl-CoA (4-HBCoA) and/or putrescine. The
invention, in particular, relates to the design of microbial
organisms capable of producing BDO, 4-HBal, 4-HBCoA and/or
putrescine by introducing one or more nucleic acids encoding a BDO,
4-HBal, 4-HBCoA and/or putrescine pathway enzyme.
[0073] In one embodiment, the invention utilizes in silico
stoichiometric models of Escherichia coli metabolism that identify
metabolic designs for biosynthetic production of 4-hydroxybutanoic
acid (4-HB), 1,4-butanediol (BDO), 4-HBal, 4-HBCoA and/or
putrescine. The results described herein indicate that metabolic
pathways can be designed and recombinantly engineered to achieve
the biosynthesis of 4-HBal, 4-HBCoA or 4-HB and downstream products
such as 1,4-butanediol or putrescine in Escherichia coli and other
cells or organisms. Biosynthetic production of 4-HB, 4-HBal,
4-HBCoA, BDO and/or putrescine, for example, for the in silico
designs can be confirmed by construction of strains having the
designed metabolic genotype. These metabolically engineered cells
or organisms also can be subjected to adaptive evolution to further
augment 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrescine biosynthesis,
including under conditions approaching theoretical maximum
growth.
[0074] In certain embodiments, the 4-HB, 4-HBal, 4-HBCoA, BDO
and/or putrescine biosynthesis characteristics of the designed
strains make them genetically stable and particularly useful in
continuous bioprocesses. Separate strain design strategies were
identified with incorporation of different non-native or
heterologous reaction capabilities into E. coli or other host
organisms leading to 4-HB and 1,4-butanediol producing metabolic
pathways from either CoA-independent succinic semialdehyde
dehydrogenase, succinyl-CoA synthetase and CoA-dependent succinic
semialdehyde dehydrogenase, or glutamate: succinic semialdehyde
transaminase. In silico metabolic designs were identified that
resulted in the biosynthesis of 4-HB in both E. coli and yeast
species from each of these metabolic pathways. The 1,4-butanediol
intermediate .gamma.-butyrolactone can be generated in culture by
spontaneous cyclization under conditions at pH<7.5, particularly
under acidic conditions, such as below pH 5.5, for example,
pH<7, pH<6.5, pH<6, and particularly at pH<5.5 or
lower.
[0075] Strains identified via the computational component of the
platform can be put into actual production by genetically
engineering any of the predicted metabolic alterations which lead
to the biosynthetic production of 4-HB, 1,4-butanediol or other
intermediate and/or downstream products. In yet a further
embodiment, strains exhibiting biosynthetic production of these
compounds can be further subjected to adaptive evolution to further
augment product biosynthesis. The levels of product biosynthesis
yield following adaptive evolution also can be predicted by the
computational component of the system.
[0076] In other specific embodiments, microbial organisms were
constructed to express a 4-HB biosynthetic pathway encoding the
enzymatic steps from succinate to 4-HB and to 4-HB-CoA.
Co-expression of succinate coenzyme A transferase, CoA-dependent
succinic semialdehyde dehydrogenase, NAD-dependent
4-hydroxybutyrate dehydrogenase and 4-hydroxybutyrate coenzyme A
transferase in a host microbial organism resulted in significant
production of 4-HB compared to host microbial organisms lacking a
4-HB biosynthetic pathway. In a further specific embodiment,
4-HB-producing microbial organisms were generated that utilized
.alpha.-ketoglutarate as a substrate by introducing nucleic acids
encoding .alpha.-ketoglutarate decarboxylase and NAD-dependent
4-hydroxybutyrate dehydrogenase.
[0077] In another specific embodiment, microbial organisms
containing a 1,4-butanediol (BDO) biosynthetic pathway were
constructed that biosynthesized BDO when cultured in the presence
of 4-HB. The BDO biosynthetic pathway consisted of a nucleic acid
encoding either a multifunctional aldehyde/alcohol dehydrogenase or
nucleic acids encoding an aldehyde dehydrogenawse and an alcohol
dehydrogenase. To support growth on 4-HB substrates, these
BDO-producing microbial organisms also expressed 4-hydroxybutyrate
CoA transferase or 4-butyrate kinase in conjunction with
phosphotranshydroxybutyrlase. In yet a further specific embodiment,
microbial organisms were generated that synthesized BDO through
exogenous expression of nucleic acids encoding a functional 4-HB
biosynthetic pathway and a functional BDO biosynthetic pathway. The
4-HB biosynthetic pathway consisted of succinate coenzyme A
transferase, CoA-dependent succinic semialdehyde dehydrogenase,
NAD-dependent 4-hydroxybutyrate dehydrogenase and 4-hydroxybutyrate
coenzyme A transferase. The BDO pathway consisted of a
multifunctional aldehyde/alcohol dehydrogenase. Further described
herein are additional pathways for production of BDO (see FIGS.
8-13).
[0078] In a further embodiment, described herein is the cloning and
expression of a carboxylic acid reductase enzyme that functions in
a 4-hydroxybutanal, 4-hydroxybutyryl-CoA or 1,4-butanediol
metabolic pathway. Advantages of employing a carboxylic acid
reductase as opposed to an acyl-CoA reductase to form
4-hydroxybutyraldehyde (4-hydroxybutanal) include lower ethanol and
GBL byproduct formation accompanying the production of BDO. Also
disclosed herein is the application of carboxylic acid reductase as
part of additional numerous pathways to produce 1,4-butanediol and
putrescine from the tricarboxylic acid (TCA) cycle metabolites, for
example, succinate, succinyl-CoA, and/or alpha-ketoglutarate.
[0079] As used herein, the term "non-naturally occurring" when used
in reference to a microbial organism or microorganism of the
invention is intended to mean that the microbial organism has at
least one genetic alteration not normally found in a naturally
occurring strain of the referenced species, including wild-type
strains of the referenced species. Genetic alterations include, for
example, modifications introducing expressible nucleic acids
encoding metabolic polypeptides, other nucleic acid additions,
nucleic acid deletions and/or other functional disruption of the
microbial organism's genetic material. Such modifications include,
for example, coding regions and functional fragments thereof, for
heterologous, homologous or both heterologous and homologous
polypeptides for the referenced species. Additional modifications
include, for example, non-coding regulatory regions in which the
modifications alter expression of a gene or operon. Exemplary
metabolic polypeptides include enzymes or proteins within a
biosynthetic pathway for a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
family of compounds.
[0080] A metabolic modification refers to a biochemical reaction
that is altered from its naturally occurring state. Therefore,
non-naturally occurring microorganisms can have genetic
modifications to nucleic acids encoding metabolic polypeptides or,
functional fragments thereof. Exemplary metabolic modifications are
disclosed herein.
[0081] As used herein, the term "isolated" when used in reference
to a microbial organism is intended to mean an organism that is
substantially free of at least one component as the referenced
microbial organism is found in nature. The term includes a
microbial organism that is removed from some or all components as
it is found in its natural environment. The term also includes a
microbial organism that is removed from some or all components as
the microbial organism is found in non-naturally occurring
environments. Therefore, an isolated microbial organism is partly
or completely separated from other substances as it is found in
nature or as it is grown, stored or subsisted in non-naturally
occurring environments. Specific examples of isolated microbial
organisms include partially pure microbes, substantially pure
microbes and microbes cultured in a medium that is non-naturally
occurring.
[0082] As used herein, the terms "microbial," "microbial organism"
or "microorganism" is intended to mean any organism that exists as
a microscopic cell that is included within the domains of archaea,
bacteria or eukarya. Therefore, the term is intended to encompass
prokaryotic or eukaryotic cells or organisms having a microscopic
size and includes bacteria, archaea and eubacteria of all species
as well as eukaryotic microorganisms such as yeast and fungi. The
term also includes cell cultures of any species that can be
cultured for the production of a biochemical.
[0083] As used herein, the term "4-hydroxybutanoic acid" is
intended to mean a 4-hydroxy derivative of butyric acid having the
chemical formula C.sub.4H.sub.8O.sub.3 and a molecular mass of
104.11 g/mol (126.09 g/mol for its sodium salt). The chemical
compound 4-hydroxybutanoic acid also is known in the art as 4-HB,
4-hydroxybutyrate, gamma-hydroxybutyric acid or GHB. The term as it
is used herein is intended to include any of the compound's various
salt forms and include, for example, 4-hydroxybutanoate and
4-hydroxybutyrate. Specific examples of salt forms for 4-HB include
sodium 4-HB and potassium 4-HB. Therefore, the terms
4-hydroxybutanoic acid, 4-HB, 4-hydroxybutyrate,
4-hydroxybutanoate, gamma-hydroxybutyric acid and GHB as well as
other art recognized names are used synonymously herein.
[0084] As used herein, the term "monomeric" when used in reference
to 4-HB is intended to mean 4-HB in a non-polymeric or
underivatized form. Specific examples of polymeric 4-HB include
poly-4-hydroxybutanoic acid and copolymers of, for example, 4-HB
and 3-HB. A specific example of a derivatized form of 4-HB is
4-HB-CoA. Other polymeric 4-HB forms and other derivatized forms of
4-HB also are known in the art.
[0085] As used herein, the term ".gamma.-butyrolactone" is intended
to mean a lactone having the chemical formula C.sub.4H.sub.6O.sub.2
and a molecular mass of 86.089 g/mol. The chemical compound
.gamma.-butyrolactone also is know in the art as GBL,
butyrolactone, 1,4-lactone, 4-butyrolactone, 4-hydroxybutyric acid
lactone, and gamma-hydroxybutyric acid lactone. The term as it is
used herein is intended to include any of the compound's various
salt forms.
[0086] As used herein, the term "1,4-butanediol" is intended to
mean an alcohol derivative of the alkane butane, carrying two
hydroxyl groups which has the chemical formula
C.sub.4H.sub.10O.sub.2 and a molecular mass of 90.12 g/mol. The
chemical compound 1,4-butanediol also is known in the art as BDO
and is a chemical intermediate or precursor for a family of
compounds referred to herein as BDO family of compounds.
[0087] As used herein, the term "4-hydroxybutanal" is intended to
mean an aledehyde having the chemical formula C.sub.4H.sub.8O.sub.2
and a molecular mass of 88.10512 g/mol. The chemical compound
4-hydroxybutanal (4-HBal) is also known in the art as
4-hydroxybutyraldehyde.
[0088] As used herein, the term "putrescine" is intended to mean a
diamine having the chemical formula C.sub.4H.sub.12N.sub.2 and a
molecular mass of 88.15148 g/mol. The chemical compound putrescine
is also known in the art as 1,4-butanediamine, 1,4-diaminobutane,
butylenediamine, tetramethylenediamine, tetramethyldiamine, and
1,4-butylenediamine.
[0089] As used herein, the term "tetrahydrofuran" is intended to
mean a heterocyclic organic compound corresponding to the fully
hydrogenated analog of the aromatic compound furan which has the
chemical formula C.sub.4H.sub.8O and a molecular mass of 72.11
g/mol. The chemical compound tetrahydrofuran also is known in the
art as THF, tetrahydrofuran, 1,4-epoxybutane, butylene oxide,
cyclotetramethylene oxide, oxacyclopentane, diethylene oxide,
oxolane, furanidine, hydrofuran, tetra-methylene oxide. The term as
it is used herein is intended to include any of the compound's
various salt forms.
[0090] As used herein, the term "CoA" or "coenzyme A" is intended
to mean an organic cofactor or prosthetic group (nonprotein portion
of an enzyme) whose presence is required for the activity of many
enzymes (the apoenzyme) to form an active enzyme system. Coenzyme A
functions in certain condensing enzymes, acts in acetyl or other
acyl group transfer and in fatty acid synthesis and oxidation,
pyruvate oxidation and in other acetylation.
[0091] As used herein, the term "substantially anaerobic" when used
in reference to a culture or growth condition is intended to mean
that the amount of oxygen is less than about 10% of saturation for
dissolved oxygen in liquid media. The term also is intended to
include sealed chambers of liquid or solid medium maintained with
an atmosphere of less than about 1% oxygen.
[0092] The non-naturally occurring microbal organisms of the
invention can contain stable genetic alterations, which refers to
microorganisms that can be cultured for greater than five
generations without loss of the alteration. Generally, stable
genetic alterations include modifications that persist greater than
10 generations, particularly stable modifications will persist more
than about 25 generations, and more particularly, stable genetic
modifications will be greater than 50 generations, including
indefinitely.
[0093] Those skilled in the art will understand that the genetic
alterations, including metabolic modifications exemplified herein
are described with reference to a suitable source or host organism
such as E. coli, yeast, or other organisms disclosed herein and
their corresponding metabolic reactions or a suitable source
organism for desired genetic material such as genes encoding
enzymes for their corresponding metabolic reactions for a desired
metabolic pathway. However, given the complete genome sequencing of
a wide variety of organisms and the high level of skill in the area
of genomics, those skilled in the art will readily be able to apply
the teachings and guidance provided herein to essentially all other
organisms. For example, the E. coli metabolic alterations
exemplified herein can readily be applied to other species by
incorporating the same or analogous encoding nucleic acid from
species other than the referenced species. Such genetic alterations
include, for example, genetic alterations of species homologs, in
general, and in particular, orthologs, paralogs or nonorthologous
gene displacements.
[0094] An ortholog is a gene or genes that are related by vertical
descent and are responsible for substantially the same or identical
functions in different organisms. For example, mouse epoxide
hydrolase and human epoxide hydrolase can be considered orthologs
for the biological function of hydrolysis of epoxides. Genes are
related by vertical descent when, for example, they share sequence
similarity of sufficient amount to indicate they are homologous, or
related by evolution from a common ancestor. Genes can also be
considered orthologs if they share three-dimensional structure but
not necessarily sequence similarity, of a sufficient amount to
indicate that they have evolved from a common ancestor to the
extent that the primary sequence similarity is not identifiable.
Genes that are orthologous can encode proteins with sequence
similarity of about 25% to 100% amino acid sequence identity. Genes
encoding proteins sharing an amino acid similarity less that 25%
can also be considered to have arisen by vertical descent if their
three-dimensional structure also shows similarities. Members of the
serine protease family of enzymes, including tissue plasminogen
activator and elastase, are considered to have arisen by vertical
descent from a common ancestor.
[0095] Orthologs include genes or their encoded gene products that
through, for example, evolution, have diverged in structure or
overall activity. For example, where one species encodes a gene
product exhibiting two functions and where such functions have been
separated into distinct genes in a second species, the three genes
and their corresponding products are considered to be orthologs.
For the production, including growth-coupled production, of a
biochemical product, those skilled in the art will understand that
the orthologous gene harboring the metabolic activity to be
introduced or disrupted is to be chosen for construction of the
non-naturally occurring microorganism. An example of orthologs
exhibiting separable activities is where distinct activities have
been separated into distinct gene products between two or more
species or within a single species. A specific example is the
separation of elastase proteolysis and plasminogen proteolysis, two
types of serine protease activity, into distinct molecules as
plasminogen activator and elastase. A second example is the
separation of mycoplasma 5'-3' exonuclease and Drosophila DNA
polymerase III activity. The DNA polymerase from the first species
can be considered an ortholog to either or both of the exonuclease
or the polymerase from the second species and vice versa.
[0096] In contrast, paralogs are homologs related by, for example,
duplication followed by evolutionary divergence and have similar or
common, but not identical functions. Paralogs can originate or
derive from, for example, the same species or from a different
species. For example, microsomal epoxide hydrolase (epoxide
hydrolase I) and soluble epoxide hydrolase (epoxide hydrolase II)
can be considered paralogs because they represent two distinct
enzymes, co-evolved from a common ancestor, that catalyze distinct
reactions and have distinct functions in the same species. Paralogs
are proteins from the same species with significant sequence
similarity to each other suggesting that they are homologous, or
related through co-evolution from a common ancestor. Groups of
paralogous protein families include HipA homologs, luciferase
genes, peptidases, and others.
[0097] A nonorthologous gene displacement is a nonorthologous gene
from one species that can substitute for a referenced gene function
in a different species. Substitution includes, for example, being
able to perform substantially the same or a similar function in the
species of origin compared to the referenced function in the
different species. Although generally, a nonorthologous gene
displacement will be identifiable as structurally related to a
known gene encoding the referenced function, less structurally
related but functionally similar genes and their corresponding gene
products nevertheless will still fall within the meaning of the
term as it is used herein. Functional similarity requires, for
example, at least some structural similarity in the active site or
binding region of a nonorthologous gene product compared to a gene
encoding the function sought to be substituted. Therefore, a
nonorthologous gene includes, for example, a paralog or an
unrelated gene.
[0098] Therefore, in identifying and constructing the non-naturally
occurring microbial organisms of the invention having 4-HB, GBL,
4-HBal, 4-HBCoA, BDO and/or putrescine biosynthetic capability,
those skilled in the art will understand with applying the teaching
and guidance provided herein to a particular species that the
identification of metabolic modifications can include
identification and inclusion or inactivation of orthologs. To the
extent that paralogs and/or nonorthologous gene displacements are
present in the referenced microorganism that encode an enzyme
catalyzing a similar or substantially similar metabolic reaction,
those skilled in the art also can utilize these evolutionally
related genes.
[0099] Orthologs, paralogs and nonorthologous gene displacements
can be determined by methods well known to those skilled in the
art. For example, inspection of nucleic acid or amino acid
sequences for two polypeptides will reveal sequence identity and
similarities between the compared sequences. Based on such
similarities, one skilled in the art can determine if the
similarity is sufficiently high to indicate the proteins are
related through evolution from a common ancestor. Algorithms well
known to those skilled in the art, such as Align, BLAST, Clustal W
and others compare and determine a raw sequence similarity or
identity, and also determine the presence or significance of gaps
in the sequence which can be assigned a weight or score. Such
algorithms also are known in the art and are similarly applicable
for determining nucleotide sequence similarity or identity.
Parameters for sufficient similarity to determine relatedness are
computed based on well known methods for calculating statistical
similarity, or the chance of finding a similar match in a random
polypeptide, and the significance of the match determined. A
computer comparison of two or more sequences can, if desired, also
be optimized visually by those skilled in the art. Related gene
products or proteins can be expected to have a high similarity, for
example, 25% to 100% sequence identity. Proteins that are unrelated
can have an identity which is essentially the same as would be
expected to occur by chance, if a database of sufficient size is
scanned (about 5%). Sequences between 5% and 24% may or may not
represent sufficient homology to conclude that the compared
sequences are related. Additional statistical analysis to determine
the significance of such matches given the size of the data set can
be carried out to determine the relevance of these sequences.
[0100] Exemplary parameters for determining relatedness of two or
more sequences using the BLAST algorithm, for example, can be as
set forth below. Briefly, amino acid sequence alignments can be
performed using BLASTP version 2.0.8 (Jan. 5, 1999) and the
following parameters: Matrix: 0 BLOSUM62; gap open: 11; gap
extension: 1; x_dropoff: 50; expect: 10.0; wordsize: 3; filter: on.
Nucleic acid sequence alignments can be performed using BLASTN
version 2.0.6 (Sep. 16, 1998) and the following parameters: Match:
1; mismatch: -2; gap open: 5; gap extension: 2; x_dropoff: 50;
expect: 10.0; wordsize: 11; filter: off. Those skilled in the art
will know what modifications can be made to the above parameters to
either increase or decrease the stringency of the comparison, for
example, and determine the relatedness of two or more
sequences.
[0101] Disclosed herein are non-naturally occurring microbial
biocatalyst or microbial organisms including a microbial organism
having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway that
includes at least one exogenous nucleic acid encoding
4-hydroxybutanoate dehydrogenase, CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, glutamate: succinic
semialdehyde transaminase, alpha-ketoglutarate decarboxylase, or
glutamate decarboxylase, wherein the exogenous nucleic acid is
expressed in sufficient amounts to produce monomeric
4-hydroxybutanoic acid (4-HB). 4-hydroxybutanoate dehydrogenase is
also referred to as 4-hydroxybutyrate dehydrogenase or 4-HB
dehydrogenase. Succinyl-CoA synthetase is also referred to as
succinyl-CoA synthase or succinyl-CoA ligase.
[0102] Also disclosed herein is a non-naturally occurring microbial
biocatalyst or microbial organism including a microbial organism
having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway having
at least one exogenous nucleic acid encoding 4-hydroxybutanoate
dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic
semialdehyde dehydrogenase, or .alpha.-ketoglutarate decarboxylase,
wherein the exogenous nucleic acid is expressed in sufficient
amounts to produce monomeric 4-hydroxybutanoic acid (4-HB).
[0103] The non-naturally occurring microbial biocatalysts or
microbial organisms can include microbial organisms that employ
combinations of metabolic reactions for biosynthetically producing
the compounds of the invention. The biosynthesized compounds can be
produced intracellularly and/or secreted into the culture medium.
Exemplary compounds produced by the non-naturally occurring
microorganisms include, for example, 4-hydroxybutanoic acid,
1,4-butanediol and .gamma.-butyrolactone.
[0104] In one embodiment, a non-naturally occurring microbial
organism is engineered to produce 4-HB. This compound is one useful
entry point into the 1,4-butanediol family of compounds. The
biochemical reactions for formation of 4-HB from succinate, from
succinate through succinyl-CoA or from .alpha.-ketoglutarate are
shown in steps 1-8 of FIG. 1.
[0105] It is understood that any combination of appropriate enzymes
of a BDO, 4-HBal, 4-HBCoA and/or putrescine pathway can be used so
long as conversion from a starting component to the BDO, 4-HBal,
4-HBCoA and/or putrescine product is achieved. Thus, it is
understood that any of the metabolic pathways disclosed herein can
be utilized and that it is well understood to those skilled in the
art how to select appropriate enzymes to achieve a desired pathway,
as disclosed herein.
[0106] In another embodiment, disclosed herein is a non-naturally
occurring microbial organism, comprising a microbial organism
having a 1,4-butanediol (BDO) pathway comprising at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, the BDO pathway comprising
4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase,
4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA oxidoreductase
(deaminating), 4-aminobutyryl-CoA transaminase, or
4-hydroxybutyryl-CoA dehydrogenase (see Example VII Table 17). The
BDO pathway further can comprise 4-hydroxybutyryl-CoA reductase
(alcohol forming), 4-hydroxybutyryl-CoA reductase, or
1,4-butanediol dehydrogenase.
[0107] It is understood by those skilled in the art that various
combinations of the pathways can be utilized, as disclosed herein.
For example, in a non-naturally occurring microbial organism, the
nucleic acids can encode 4-aminobutyrate CoA transferase,
4-aminobutyryl-CoA hydrolase, or 4-aminobutyrate-CoA ligase;
4-aminobutyryl-CoA oxidoreductase (deaminating) or
4-aminobutyryl-CoA transaminase; and 4-hydroxybutyryl-CoA
dehydrogenase. Other exemplary combinations are specifically
describe below and further can be found in FIGS. 8-13. For example,
the BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase
(alcohol forming), 4-hydroxybutyryl-CoA reductase, or
1,4-butanediol dehydrogenase.
[0108] Additionally disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BDO,
the BDO pathway comprising 4-aminobutyrate CoA transferase,
4-aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase,
4-aminobutyryl-CoA reductase (alcohol forming), 4-aminobutyryl-CoA
reductase, 4-aminobutan-1-ol dehydrogenase, 4-aminobutan-1-ol
oxidoreductase (deaminating) or 4-aminobutan-1-ol transaminase (see
Example VII and Table 18), and can further comprise 1,4-butanediol
dehydrogenase. For example, the exogenous nucleic acids can encode
4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, or
4-aminobutyrate-CoA ligase; 4-aminobutyryl-CoA reductase (alcohol
forming); and 4-aminobutan-1-ol oxidoreductase (deaminating) or
4-aminobutan-1-ol transaminase. In addition, the nucleic acids can
encode. 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA
hydrolase, or 4-aminobutyrate-CoA ligase; 4-aminobutyryl-CoA
reductase; 4-aminobutan-1-ol dehydrogenase; and 4-aminobutan-1-ol
oxidoreductase (deaminating) or 4-aminobutan-1-ol transaminase.
[0109] Also disclosed herein is a non-naturally occurring microbial
organism, comprising a microbial organism having a BDO pathway
comprising at least one exogenous nucleic acid encoding a BDO
pathway enzyme expressed in a sufficient amount to produce BDO, the
BDO pathway comprising 4-aminobutyrate kinase, 4-aminobutyraldehyde
dehydrogenase (phosphorylating), 4-aminobutan-1-ol dehydrogenase,
4-aminobutan-1-ol oxidoreductase (deaminating), 4-aminobutan-1-ol
transaminase, [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase
(deaminating), [(4-aminobutanolyl)oxy]phosphonic acid transaminase,
4-hydroxybutyryl-phosphate dehydrogenase, or 4-hydroxybutyraldehyde
dehydrogenase (phosphorylating) (see Example VII and Table 19). For
example, the exogenous nucleic acids can encode 4-aminobutyrate
kinase; 4-aminobutyraldehyde dehydrogenase (phosphorylating);
4-aminobutan-1-ol dehydrogenase; and 4-aminobutan-1-ol
oxidoreductase (deaminating) or 4-aminobutan-1-ol transaminase.
Alternatively, the exogenous nucleic acids can encode
4-aminobutyrate kinase; [(4-aminobutanolyl)oxy]phosphonic acid
oxidoreductase (deaminating) or [(4-aminobutanolyl)oxy]phosphonic
acid transaminase; 4-hydroxybutyryl-phosphate dehydrogenase; and
4-hydroxybutyraldehyde dehydrogenase (phosphorylating).
[0110] Additionally disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BDO,
the BDO pathway comprising alpha-ketoglutarate 5-kinase,
2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating),
2,5-dioxopentanoic acid reductase, alpha-ketoglutarate CoA
transferase, alpha-ketoglutaryl-CoA hydrolase,
alpha-ketoglutaryl-CoA ligase, alpha-ketoglutaryl-CoA reductase,
5-hydroxy-2-oxopentanoic acid dehydrogenase, alpha-ketoglutaryl-CoA
reductase (alcohol forming), 5-hydroxy-2-oxopentanoic acid
decarboxylase, or 5-hydroxy-2-oxopentanoic acid dehydrogenase
(decarboxylation) (see Example VIII and Table 20). The BDO pathway
can further comprise 4-hydroxybutyryl-CoA reductase (alcohol
forming), 4-hydroxybutyryl-CoA reductase, or 1,4-butanediol
dehydrogenase. For example, the exogenous nucleic acids can encode
alpha-ketoglutarate 5-kinase; 2,5-dioxopentanoic semialdehyde
dehydrogenase (phosphorylating); 2,5-dioxopentanoic acid reductase;
and 5-hydroxy-2-oxopentanoic acid decarboxylase. Alternatively, the
exogenous nucleic acids can encode alpha-ketoglutarate 5-kinase;
2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating);
2,5-dioxopentanoic acid reductase; and 5-hydroxy-2-oxopentanoic
acid dehydrogenase (decarboxylation). Alternatively, the exogenous
nucleic acids can encode alpha-ketoglutarate CoA transferase,
alpha-ketoglutaryl-CoA hydrolase, or alpha-ketoglutaryl-CoA ligase;
alpha-ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid
dehydrogenase; and 5-hydroxy-2-oxopentanoic acid decarboxylase. In
another embodiment, the exogenous nucleic acids can encode
alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA
hydrolase, or alpha-ketoglutaryl-CoA ligase; alpha-ketoglutaryl-CoA
reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase, and
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation).
Alternatively, the exogenous nucleic acids can encode
alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA
hydrolase, or alpha-ketoglutaryl-CoA ligase; alpha-ketoglutaryl-CoA
reductase (alcohol forming); and 5-hydroxy-2-oxopentanoic acid
decarboxylase. In yet another embodiment, the exogenous nucleic
acids can encode alpha-ketoglutarate CoA transferase,
alpha-ketoglutaryl-CoA hydrolase, or alpha-ketoglutaryl-CoA ligase;
alpha-ketoglutaryl-CoA reductase (alcohol forming); and
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation).
[0111] Further disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BDO,
the BDO pathway comprising glutamate CoA transferase, glutamyl-CoA
hydrolase, glutamyl-CoA ligase, glutamate 5-kinase,
glutamate-5-semialdehyde dehydrogenase (phosphorylating),
glutamyl-CoA reductase, glutamate-5-semialdehyde reductase,
glutamyl-CoA reductase (alcohol forming),
2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating),
2-amino-5-hydroxypentanoic acid transaminase,
5-hydroxy-2-oxopentanoic acid decarboxylase,
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation) (see
Example IX and Table 21). For example, the exogenous nucleic acids
can encode glutamate CoA transferase, glutamyl-CoA hydrolase, or
glutamyl-CoA ligase; glutamyl-CoA reductase;
glutamate-5-semialdehyde reductase; 2-amino-5-hydroxypentanoic acid
oxidoreductase (deaminating) or 2-amino-5-hydroxypentanoic acid
transaminase; and 5-hydroxy-2-oxopentanoic acid decarboxylase or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation).
Alternatively, the exogenous nucleic acids can encode glutamate
5-kinase; glutamate-5-semialdehyde dehydrogenase (phosphorylating);
glutamate-5-semialdehyde reductase; 2-amino-5-hydroxypentanoic acid
oxidoreductase (deaminating) or 2-amino-5-hydroxypentanoic acid
transaminase; and 5-hydroxy-2-oxopentanoic acid decarboxylase or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). In
still another embodiment, the exogenous nucleic acids can encode
glutamate CoA transferase, glutamyl-CoA hydrolase, or glutamyl-CoA
ligase; glutamyl-CoA reductase (alcohol forming);
2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating) or
2-amino-5-hydroxypentanoic acid transaminase; and
5-hydroxy-2-oxopentanoic acid decarboxylase or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). In
yet another embodiment, the exogenous nucleic acids can encode
glutamate 5-kinase; glutamate-5-semialdehyde dehydrogenase
(phosphorylating); 2-amino-5-hydroxypentanoic acid oxidoreductase
(deaminating) or 2-amino-5-hydroxypentanoic acid transaminase; and
5-hydroxy-2-oxopentanoic acid decarboxylase or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation).
[0112] Also disclosed herein is a non-naturally occurring microbial
organism, comprising a microbial organism having a BDO pathway
comprising at least one exogenous nucleic acid encoding a BDO
pathway enzyme expressed in a sufficient amount to produce BDO, the
BDO pathway comprising 3-hydroxybutyryl-CoA dehydrogenase,
3-hydroxybutyryl-CoA dehydratase, vinylacetyl-CoA
.DELTA.-isomerase, or 4-hydroxybutyryl-CoA dehydratase (see Example
X and Table 22). For example, the exogenous nucleic acids can
encode 3-hydroxybutyryl-CoA dehydrogenase; 3-hydroxybutyryl-CoA
dehydratase; vinylacetyl-CoA .DELTA.-isomerase; and
4-hydroxybutyryl-CoA dehydratase.
[0113] Further disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BDO,
the BDO pathway comprising homoserine deaminase, homoserine CoA
transferase, homoserine-CoA hydrolase, homoserine-CoA ligase,
homoserine-CoA deaminase, 4-hydroxybut-2-enoyl-CoA transferase,
4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA
ligase, 4-hydroxybut-2-enoate reductase, 4-hydroxybutyryl-CoA
transferase, 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA
ligase, or 4-hydroxybut-2-enoyl-CoA reductase (see Example XI and
Table 23). For example, the exogenous nucleic acids can encode
homoserine deaminase; 4-hydroxybut-2-enoyl-CoA transferase,
4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA
ligase; 4-hydroxybut-2-enoyl-CoA reductase. Alternatively, the
exogenous nucleic acids can encode homoserine CoA transferase,
homoserine-CoA hydrolase, or homoserine-CoA ligase; homoserine-CoA
deaminase; and 4-hydroxybut-2-enoyl-CoA reductase. In a further
embodiment, the exogenous nucleic acids can encode homoserine
deaminase; 4-hydroxybut-2-enoate reductase; and
4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA hydrolase,
or 4-hydroxybutyryl-CoA ligase. Alternatively, the exogenous
nucleic acids can encode homoserine CoA transferase, homoserine-CoA
hydrolase, or homoserine-CoA ligase; homoserine-CoA deaminase; and
4-hydroxybut-2-enoyl-CoA reductase.
[0114] Further disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BOD,
the BDO pathway comprising succinyl-CoA reductase (alcohol
forming), 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA
ligase, 4-hydroxybutanal dehydrogenase (phosphorylating) (see Table
15). Such a BDO pathway can further comprise succinyl-CoA
reductase, 4-hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA
transferase, 4-hydroxybutyrate kinase,
phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase,
4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol
dehydrogenase.
[0115] Additionally disclosed herein is a non-naturally occurring
microbial organism, comprising a microbial organism having a BDO
pathway comprising at least one exogenous nucleic acid encoding a
BDO pathway enzyme expressed in a sufficient amount to produce BDO,
the BDO pathway comprising glutamate dehydrogenase, 4-aminobutyrate
oxidoreductase (deaminating), 4-aminobutyrate transaminase,
glutamate decarboxylase, 4-hydroxybutyryl-CoA hydrolase,
4-hydroxybutyryl-CoA ligase, 4-hydroxybutanal dehydrogenase
(phosphorylating)(see Table 16). Such a BDO pathway can further
comprise alpha-ketoglutarate decarboxylase, 4-hydroxybutyrate
dehydrogenase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate
kinase, phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA
reductase, 4-hydroxybutyryl-CoA reductase (alcohol forming), or
1,4-butanediol dehydrogenase.
[0116] The pathways described above are merely exemplary. One
skilled in the art can readily select appropriate pathways from
those disclosed herein to obtain a suitable BDO pathway or other
metabolic pathway, as desired.
[0117] The invention provides genetically modified organisms that
allow improved production of a desired product such as BDO by
increasing the product or decreasing undesirable byproducts. As
disclosed herein, the invention provides a non-naturally occurring
microbial organism, comprising a microbial organism having a
1,4-butanediol (BDO) pathway comprising at least one exogenous
nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO. In one embodiment, the microbial
organism is genetically modified to express exogenous succinyl-CoA
synthetase (see Example XII). For example, the succinyl-CoA
synthetase can be encoded by an Escherichia coli sucCD genes.
[0118] In another embodiment, the microbial organism is genetically
modified to express exogenous alpha-ketoglutarate decarboxylase
(see Example XIII) For example, the alpha-ketoglutarate
decarboxylase can be encoded by the Mycobacterium bovis sucA gene.
In still another embodiment, the microbial organism is genetically
modified to express exogenous succinate semialdehyde dehydrogenase
and 4-hydroxybutyrate dehydrogenase and optionally
4-hydroxybutyryl-CoA/acetyl-CoA transferase (see Example XIII) For
example, the succinate semialdehyde dehydrogenase (CoA-dependent),
4-hydroxybutyrate dehydrogenase and 4-hydroxybutyryl-CoA/acetyl-CoA
transferase can be encoded by Porphyromonas gingivalis W83 genes.
In an additional embodiment, the microbial organism is genetically
modified to express exogenous butyrate kinase and
phosphotransbutyrylase (see Example XIII) For example, the butyrate
kinase and phosphotransbutyrylase can be encoded by Clostridium
acetobutilicum buk1 and ptb genes.
[0119] In yet another embodiment, the microbial organism is
genetically modified to express exogenous 4-hydroxybutyryl-CoA
reductase (see Example XIII) For example, the 4-hydroxybutyryl-CoA
reductase can be encoded by Clostridium beijerinckii ald gene.
Additionally, in an embodiment of the invention, the microbial
organism is genetically modified to express exogenous
4-hydroxybutanal reductase (see Example XIII) For example, the
4-hydroxybutanal reductase can be encoded by Geobacillus
thermoglucosidasius adh1 gene. In another embodiment, the microbial
organism is genetically modified to express exogenous pyruvate
dehydrogenase subunits (see Example XIV). For example, the
exogenous pyruvate dehydrogenase can be NADH insensitive. The
pyruvate dehydrogenase subunit can be encoded by the Klebsiella
pneumonia lpdA gene. In a particular embodiment, the pyruvate
dehydrogenase subunit genes of the microbial organism can be under
the control of a pyruvate formate lyase promoter.
[0120] In still another embodiment, the microbial organism is
genetically modified to disrupt a gene encoding an aerobic
respiratory control regulatory system (see Example XV). For
example, the disruption can be of the arcA gene. Such an organism
can further comprise disruption of a gene encoding malate
dehydrogenase. In a further embodiment, the microbial organism is
genetically modified to express an exogenous NADH insensitive
citrate synthase (see Example XV). For example, the NADH
insensitive citrate synthase can be encoded by gltA, such as an
R163L mutant of gltA. In still another embodiment, the microbial
organism is genetically modified to express exogenous
phosphoenolpyruvate carboxykinase (see Example XVI). For example,
the phosphoenolpyruvate carboxykinase can be encoded by an
Haemophilus influenza phosphoenolpyruvate carboxykinase gene.
[0121] It is understood that any of a number of genetic
modifications, as disclosed herein, can be used alone or in various
combinations of one or more of the genetic modifications disclosed
herein to increase the production of BDO in a BDO producing
microbial organism. In a particular embodiment, the microbial
organism can be genetically modified to incorporate any and up to
all of the genetic modifications that lead to increased production
of BDO. In a particular embodiment, the microbial organism
containing a BDO pathway can be genetically modified to express
exogenous succinyl-CoA synthetase; to express exogenous
alpha-ketoglutarate decarboxylase; to express exogenous succinate
semialdehyde dehydrogenase and 4-hydroxybutyrate dehydrogenase and
optionally 4-hydroxybutyryl-CoA/acetyl-CoA transferase; to express
exogenous butyrate kinase and phosphotransbutyrylase; to express
exogenous 4-hydroxybutyryl-CoA reductase; and to express exogenous
4-hydroxybutanal reductase; to express exogenous pyruvate
dehydrogenase; to disrupt a gene encoding an aerobic respiratory
control regulatory system; to express an exogenous NADH insensitive
citrate synthase; and to express exogenous phosphoenolpyruvate
carboxykinase. Such strains for improved production are described
in Examples XII-XIX. It is thus understood that, in addition to the
modifications described above, such strains can additionally
include other modifications disclosed herein. Such modifications
include, but are not limited to, deletion of endogenous lactate
dehydrogenase (ldhA), alcohol dehydrogenase (adhE), and/or pyruvate
formate lyase (pflB)(see Examples XII-XIX and Table 28).
[0122] Additionally provided is a microbial organism in which one
or more genes encoding the exogenously expressed enzymes are
integrated into the fimD locus of the host organism (see Example
XVII). For example, one or more genes encoding a BDO pathway enzyme
can be integrated into the fimD locus for increased production of
BDO. Further provided is a microbial organism expressing a
non-phosphotransferase sucrose uptake system that increases
production of BDO.
[0123] Although the genetically modified microbial organisms
disclosed herein are exemplified with microbial organisms
containing particular BDO pathway enzymes, it is understood that
such modifications can be incorporated into any microbial organism
having a BDO, 4-HBal, 4-HBCoA and/or putrescine pathway suitable
for enhanced production in the presence of the genetic
modifications. The microbial organisms of the invention can thus
have any of the BDO, 4-HBal, 4-HBCoA and/or putrescine pathways
disclosed herein. For example, the BDO pathway can comprise
4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase,
CoA-dependent succinic semialdehyde dehydrogenase,
4-hydroxybutyrate:CoA transferase, 4-butyrate kinase,
phosphotransbutyrylase, alpha-ketoglutarate decarboxylase, aldehyde
dehydrogenase, alcohol dehydrogenase or an aldehyde/alcohol
dehydrogenase (see FIG. 1). Alternatively, the BDO pathway can
comprise 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA
hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA
oxidoreductase (deaminating), 4-aminobutyryl-CoA transaminase, or
4-hydroxybutyryl-CoA dehydrogenase (see Table 17). Such a BDO
pathway can further comprise 4-hydroxybutyryl-CoA reductase
(alcohol forming), 4-hydroxybutyryl-CoA reductase, or
1,4-butanediol dehydrogenase
[0124] Additionally, the BDO pathway can comprise 4-aminobutyrate
CoA transferase, 4-aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA
ligase, 4-aminobutyryl-CoA reductase (alcohol forming),
4-aminobutyryl-CoA reductase, 4-aminobutan-1-ol dehydrogenase,
4-aminobutan-1-ol oxidoreductase (deaminating) or 4-aminobutan-1-ol
transaminase (see Table 18). Also, the BDO pathway can comprise
4-aminobutyrate kinase, 4-aminobutyraldehyde dehydrogenase
(phosphorylating), 4-aminobutan-1-ol dehydrogenase,
4-aminobutan-1-ol oxidoreductase (deaminating), 4-aminobutan-1-ol
transaminase, [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase
(deaminating), [(4-aminobutanolyl)oxy]phosphonic acid transaminase,
4-hydroxybutyryl-phosphate dehydrogenase, or 4-hydroxybutyraldehyde
dehydrogenase (phosphorylating) (see Table 19). Such a pathway can
further comprise 1,4-butanediol dehydrogenase.
[0125] The BDO pathway can also comprise alpha-ketoglutarate
5-kinase, 2,5-dioxopentanoic semialdehyde dehydrogenase
(phosphorylating), 2,5-dioxopentanoic acid reductase,
alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA
hydrolase, alpha-ketoglutaryl-CoA ligase, alpha-ketoglutaryl-CoA
reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase,
alpha-ketoglutaryl-CoA reductase (alcohol forming),
5-hydroxy-2-oxopentanoic acid decarboxylase, or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation)(see
Table 20). Such a BDO pathway can further comprise
4-hydroxybutyryl-CoA reductase (alcohol forming),
4-hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase.
Additionally, the BDO pathway can comprise glutamate CoA
transferase, glutamyl-CoA hydrolase, glutamyl-CoA ligase, glutamate
5-kinase, glutamate-5-semialdehyde dehydrogenase (phosphorylating),
glutamyl-CoA reductase, glutamate-5-semialdehyde reductase,
glutamyl-CoA reductase (alcohol forming),
2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating),
2-amino-5-hydroxypentanoic acid transaminase,
5-hydroxy-2-oxopentanoic acid decarboxylase,
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation)(see
Table 21). Such a BDO pathway can further comprise
4-hydroxybutyryl-CoA reductase (alcohol forming),
4-hydroxybutyryl-CoA reductase, or 1,4-butanediol
dehydrogenase.
[0126] Additionally, the BDO pathway can comprise
3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxybutyryl-CoA
dehydratase, vinylacetyl-CoA .DELTA.-isomerase, or
4-hydroxybutyryl-CoA dehydratase (see Table 22). Also, the BDO
pathway can comprise homoserine deaminase, homoserine CoA
transferase, homoserine-CoA hydrolase, homoserine-CoA ligase,
homoserine-CoA deaminase, 4-hydroxybut-2-enoyl-CoA transferase,
4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA
ligase, 4-hydroxybut-2-enoate reductase, 4-hydroxybutyryl-CoA
transferase, 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA
ligase, or 4-hydroxybut-2-enoyl-CoA reductase (see Table 23). Such
a BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase
(alcohol forming), 4-hydroxybutyryl-CoA reductase, or
1,4-butanediol dehydrogenase.
[0127] The BDO pathway can additionally comprise succinyl-CoA
reductase (alcohol forming), 4-hydroxybutyryl-CoA hydrolase,
4-hydroxybutyryl-CoA ligase, or 4-hydroxybutanal dehydrogenase
(phosphorylating) (see Table 15). Such a pathway can further
comprise succinyl-CoA reductase, 4-hydroxybutyrate dehydrogenase,
4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate kinase,
phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase,
4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol
dehydrogenase. Also, the BDO pathway can comprise glutamate
dehydrogenase, 4-aminobutyrate oxidoreductase (deaminating),
4-aminobutyrate transaminase, glutamate decarboxylase,
4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase, or
4-hydroxybutanal dehydrogenase (phosphorylating)(see Table 16).
Such a BDO pathway can further comprise alpha-ketoglutarate
decarboxylase, 4-hydroxybutyrate dehydrogenase,
4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate kinase,
phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase,
4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol
dehydrogenase.
[0128] The invention additionally provides a non-naturally
occurring microbial organism, comprising a 4-hydroxybutanal pathway
comprising at least one exogenous nucleic acid encoding a
4-hydroxybutanal pathway enzyme expressed in a sufficient amount to
produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
succinyl-CoA reductase (aldehyde forming); 4-hydroxybutyrate
dehydrogenase; and 4-hydroxybutyrate reductase (see FIG. 58, steps
A-C-D). The invention also provides a non-naturally occurring
microbial organism, comprising a 4-hydroxybutanal pathway
comprising at least one exogenous nucleic acid encoding a
4-hydroxybutanal pathway enzyme expressed in a sufficient amount to
produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
alpha-ketoglutarate decarboxylase; 4-hydroxybutyrate dehydrogenase;
and 4-hydroxybutyrate reductase (FIG. 58, steps B-C-D).
[0129] The invention further provides a non-naturally occurring
microbial organism, comprising a 4-hydroxybutanal pathway
comprising at least one exogenous nucleic acid encoding a
4-hydroxybutanal pathway enzyme expressed in a sufficient amount to
produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
succinate reductase; 4-hydroxybutyrate dehydrogenase, and
4-hydroxybutyrate reductase (see FIG. 62, steps F-C-D). In yet
another embodiment, the invention provides a non-naturally
occurring microbial organism, comprising a 4-hydroxybutanal pathway
comprising at least one exogenous nucleic acid encoding a
4-hydroxybutanal pathway enzyme expressed in a sufficient amount to
produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
alpha-ketoglutarate decarboxylase, or glutamate dehydrogenase or
glutamate transaminase and glutamate decarboxylase and
4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase;
4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase
(see FIG. 62, steps B or ((J or K)-L-(M or N))-C-D).
[0130] The invention also provides a non-naturally occurring
microbial organism, comprising a 4-hydroxybutanal pathway
comprising at least one exogenous nucleic acid encoding a
4-hydroxybutanal pathway enzyme expressed in a sufficient amount to
produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate
dehydrogenase; and 5-hydroxy-2-oxopentanoate decarboxylase (see
FIG. 62, steps X-Y-Z). In yet another embodiment, the invention
provides a non-naturally occurring microbial organism, comprising a
4-hydroxybutyryl-CoA pathway comprising at least one exogenous
nucleic acid encoding a 4-hydroxybutyryl-CoA pathway enzyme
expressed in a sufficient amount to produce 4-hydroxybutyryl-CoA,
the 4-hydroxybutyryl-CoA pathway comprising alpha-ketoglutarate
reductase; 5-hydroxy-2-oxopentanoate dehydrogenase; and
5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation) (see FIG.
62, steps X-Y-AA).
[0131] The invention additionally provides a non-naturally
occurring microbial organism, comprising a putrescine pathway
comprising at least one exogenous nucleic acid encoding a
putrescine pathway enzyme expressed in a sufficient amount to
produce putrescine, the putrescine pathway comprising succinate
reductase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate
transaminase; 4-aminobutyrate reductase; and putrescine
dehydrogenase or putrescine transaminase (see FIG. 63, steps
F-M/N-C-D/E). In still another embodiment, the invention provides a
non-naturally occurring microbial organism, comprising a putrescine
pathway comprising at least one exogenous nucleic acid encoding a
putrescine pathway enzyme expressed in a sufficient amount to
produce putrescine, the putrescine pathway comprising
alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or
4-aminobutyrate transaminase; 4-aminobutyrate reductase; and
putrescine dehydrogenase or putrescine transaminase (see FIG. 63,
steps B-M/N-C-D/E). The invention additionally provides a
non-naturally occurring microbial organism, comprising a putrescine
pathway comprising at least one exogenous nucleic acid encoding a
putrescine pathway enzyme expressed in a sufficient amount to
produce putrescine, the putrescine pathway comprising glutamate
dehydrogenase or glutamate transaminase; glutamate decarboxylase;
4-aminobutyrate reductase; and putrescine dehydrogenase or
putrescine transaminase (see FIG. 63, steps J/K-L-C-D/E).
[0132] The invention provides in another embodiment a non-naturally
occurring microbial organism, comprising a putrescine pathway
comprising at least one exogenous nucleic acid encoding a
putrescine pathway enzyme expressed in a sufficient amount to
produce putrescine, the putrescine pathway comprising
alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate
dehydrogenase or 5-amino-2-oxopentanoate transaminase;
5-amino-2-oxopentanoate decarboxylase; and putrescine dehydrogenase
or putrescine transaminase (see FIG. 63, steps 0-P/Q-R-D/E). Also
provided is a non-naturally occurring microbial organism,
comprising a putrescine pathway comprising at least one exogenous
nucleic acid encoding a putrescine pathway enzyme expressed in a
sufficient amount to produce putrescine, the putrescine pathway
comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate
dehydrogenase or 5-amino-2-oxopentanoate transaminase; ornithine
dehydrogenase or ornithine transaminase; and ornithine
decarboxylase (see FIG. 63, steps O-P/Q-S/T-U).
[0133] In an additional embodiment, the invention provides a
non-naturally occurring microbial organism having a 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine pathway, wherein the non-naturally
occurring microbial organism comprises at least one exogenous
nucleic acid encoding an enzyme or protein that converts a
substrate of any of the pathways disclosed herein (see, for
example, the Examples and FIGS. 1, 8-13, 58, 62 and 63). In an
exmemplary embodiment for producing BDO, the microbial organism can
convert a substrate to a product selected from the group consisting
of succinate to succinyl-CoA; succinyl-CoA to succinic
semialdehyde; succinic semialdehyde to 4-hydroxybutrate;
4-hydroxybutyrate to 4-hydroxybutyryl-phosphate;
4-hydroxybutyryl-phosphate to 4-hydroxtbutyryl-CoA;
4-hydroxybutyryl-CoA to 4-hydroxybutanal; and 4-hydroxybutanal to
1,4-butanediol. In a pathway for producing 4-HBal, a microbial
organism can convert, for example, succinate to succinic
semialdehyde; succinic semialdehyde to 4-hydroxybutyrate; and
4-hydroxybutyrate to 4-hydroxybutanal. Such an organism can
additionally include activity to convert 4-hydroxybutanal to
1,4-butanediol in order to produce BDO. Yet another pathway for
producing 4-HBal can be, for example, alpha-ketoglutarate to
succinic semialdehyde; succinic semialdehyde to 4-hydroxybutyrate;
and 4-hydroxybutyrate to 4-hydroxybutanal. An alternative pathway
for producing 4-HBal can be, for example, alpha-ketoglutarate to
2,5-dioxopentanoic acid; 2,5-dioxopentanoic acid to
5-hydroxy-2-oxopentanooic acid; and 5-hydroxy-2-oxopentanoic acid
to 4-hydroxybutanal. An exemplary 4-hydroxybutyryl-CoA pathway can
be, for example, alpha-ketoglutarate to 2,5-dioxopentanoic acid;
2,5-dioxopentanoic acid to 5-hydroxy-2-oxopentanoic acid; and
5-hydroxy-2-oxopentanoic acid to 4-hydroxybutyryl-CoA. An exemplary
putrescine pathway can be, for example, succinate to succinyl-CoA;
succinyl-CoA to succinic semialdehyde; succinic semialdehyde to
4-aminobutyrate; 4-aminobutyrate to 4-aminobutanal; and
4-aminobutanal to putrescine. An alternative putrescine pathway can
be, for example, succinate to succinic semialdehyde; succinic
semialdehyde to 4-aminobutyrate; 4-aminobutyrate to 4-aminobutanal;
and 4-aminobutanal to putrescine. One skilled in the art will
understand that these are merely exemplary and that any of the
substrate-product pairs disclosed herein suitable to produce a
desired product and for which an appropriate activity is available
for the conversion can be readily determined by one skilled in the
art based on the teachings herein. Thus, the invention provides a
non-naturally occurring microbial organism containing at least one
exogenous nucleic acid encoding an enzyme or protein, where the
enzyme or protein converts the substrates and products of a pathway
(see FIGS. 1, 8-13, 58, 62 and 63).
[0134] While generally described herein as a microbial organism
that contains a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway,
it is understood that the invention additionally provides a
non-naturally occurring microbial organism comprising at least one
exogenous nucleic acid encoding a 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathway enzyme or protein expressed in a sufficient
amount to produce an intermediate of a 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine pathway. For example, as disclosed herein, 4-HB,
4-HBal, 4-HBCoA, BDO and putrescine pathways are exemplified in
FIGS. 1, 8-13, 58, 62 and 63. Therefore, in addition to a microbial
organism containing, for example, a BDO pathway that produces BDO,
the invention additionally provides a non-naturally occurring
microbial organism comprising at least one exogenous nucleic acid
encoding a BDO pathway enzyme, where the microbial organism
produces a BDO pathway intermediate as a product rather than an
intermediate of the pathway. In one exemplary embodiment as shown
in FIG. 62, for example, the invention provides a microbial
organism that produces succinyl-CoA, succinic semialdehyde,
4-hydroxybutyrate, 4-hydroxybutyryl-phosphate,
4-hydroxybutyryl-CoA, or 4-hydroxybutanal as a product rather than
an intermediate. Another exemplary embodiment includes, for
example, a microbial organism that produces alpha-ketoglutarate,
2,5-dioxopentanoic acid, 5-hydroxy-2-oxopentanoic acid, or
4-hydroxybutanal as a product rather than an intermediate. An
exemplary embodiment in a putrescine pathway includes, for example,
a microbial organism that produces glutamate, 4-aminobutyrate, or
4-aminobutanal as a product rather than an intermediate. An
alternative embodiment in a putrescine pathway can be, for example,
a microbial organism that produces 2,5-dioxopentanoate,
5-amino-2-oxopentanoate, or ornithine as a product rather than an
intermediate.
[0135] It is understood that any of the pathways disclosed herein,
as described in the Examples and exemplified in the Figures,
including the pathways of FIGS. 1, 8-13, 58, 62 and 63, can be
utilized to generate a non-naturally occurring microbial organism
that produces any pathway intermediate or product, as desired. As
disclosed herein, such a microbial organism that produces an
intermediate can be used in combination with another microbial
organism expressing downstream pathway enzymes to produce a desired
product. However, it is understood that a non-naturally occurring
microbial organism that produces a 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathway intermediate can be utilized to produce the
intermediate as a desired product.
[0136] The invention is described herein with general reference to
the metabolic reaction, reactant or product thereof, or with
specific reference to one or more nucleic acids or genes encoding
an enzyme associated with or catalyzing the referenced metabolic
reaction, reactant or product. Unless otherwise expressly stated
herein, those skilled in the art will understand that reference to
a reaction also constitutes reference to the reactants and products
of the reaction. Similarly, unless otherwise expressly stated
herein, reference to a reactant or product also references the
reaction and that reference to any of these metabolic constitutes
also references the gene or genes encoding the enzymes that
catalyze the referenced reaction, reactant or product. Likewise,
given the well known fields of metabolic biochemistry, enzymology
and genomics, reference herein to a gene or encoding nucleic acid
also constitutes a reference to the corresponding encoded enzyme
and the reaction it catalyzes as well as the reactants and products
of the reaction.
[0137] The production of 4-HB via biosynthetic modes using the
microbial organisms of the invention is particularly useful because
it can produce monomeric 4-HB. The non-naturally occurring
microbial organisms of the invention and their biosynthesis of 4-HB
and BDO family compounds also is particularly useful because the
4-HB product can be (1) secreted; (2) can be devoid of any
derivatizations such as Coenzyme A; (3) avoids thermodynamic
changes during biosynthesis; (4) allows direct biosynthesis of BDO,
and (5) allows for the spontaneous chemical conversion of 4-HB to
.gamma.-butyrolactone (GBL) in acidic pH medium. This latter
characteristic also is particularly useful for efficient chemical
synthesis or biosynthesis of BDO family compounds such as
1,4-butanediol and/or tetrahydrofuran (THF), for example.
[0138] Microbial organisms generally lack the capacity to
synthesize 4-HB and therefore any of the compounds disclosed herein
to be within the 1,4-butanediol family of compounds or known by
those in the art to be within the 1,4-butanediol family of
compounds. Moreover, organisms having all of the requisite
metabolic enzymatic capabilities are not known to produce 4-HB from
the enzymes described and biochemical pathways exemplified herein.
Rather, with the possible exception of a few anaerobic
microorganisms described further below, the microorganisms having
the enzymatic capability to use 4-HB as a substrate to produce, for
example, succinate. In contrast, the non-naturally occurring
microbial organisms of the invention can generate 4-HB, 4-HBal,
4-HBCoA, BDO and/or putrescine as a product. As described above,
the biosynthesis of 4-HB in its monomeric form is not only
particularly useful in chemical synthesis of BDO family of
compounds, it also allows for the further biosynthesis of BDO
family compounds and avoids altogether chemical synthesis
procedures.
[0139] The non-naturally occurring microbial organisms of the
invention that can produce 4-HB, 4-HBal, 4-HBCoA, BDO and/or
putrescine are produced by ensuring that a host microbial organism
includes functional capabilities for the complete biochemical
synthesis of at least one 4-HB, 4-HBal, 4-HBCoA, BDO and/or
putrscine biosynthetic pathway of the invention. Ensuring at least
one requisite 4-HB, 4-HBal, 4-HBCoA or BDO biosynthetic pathway
confers 4-HB biosynthesis capability onto the host microbial
organism.
[0140] Several 4-HB biosynthetic pathways are exemplified herein
and shown for purposes of illustration in FIG. 1. Additional 4-HB
and BDO pathways are described in FIGS. 8-13. One 4-HB biosynthetic
pathway includes the biosynthesis of 4-HB from succinate (the
succinate pathway). The enzymes participating in this 4-HB pathway
include CoA-independent succinic semialdehyde dehydrogenase and
4-hydroxybutanoate dehydrogenase. In this pathway, CoA-independent
succinic semialdehyde dehydrogenase catalyzes the reverse reaction
to the arrow shown in FIG. 1. Another 4-HB biosynthetic pathway
includes the biosynthesis from succinate through succinyl-CoA (the
succinyl-CoA pathway). The enzymes participating in this 4-HB
pathway include succinyl-CoA synthetase, CoA-dependent succinic
semialdehyde dehydrogenase and 4-hydroxybutanoate dehydrogenase.
Three other 4-HB biosynthetic pathways include the biosynthesis of
4-HB from .alpha.-ketoglutarate (the .alpha.-ketoglutarate
pathways). Hence, a third 4-HB biosynthetic pathway is the
biosynthesis of succinic semialdehyde through glutamate: succinic
semialdehyde transaminase, glutamate decarboxylase and
4-hydroxybutanoate dehydrogenase. A fourth 4-HB biosynthetic
pathway also includes the biosynthesis of 4-HB from
.alpha.-ketoglutarate, but utilizes .alpha.-ketoglutarate
decarboxylase to catalyze succinic semialdehyde synthesis.
4-hydroxybutanoate dehydrogenase catalyzes the conversion of
succinic semialdehyde to 4-HB. A fifth 4-HB biosynthetic pathway
includes the biosynthesis from .alpha.-ketoglutarate through
succinyl-CoA and utilizes .alpha.-ketoglutarate dehydrogenase to
produce succinyl-CoA, which funnels into the succinyl-CoA pathway
described above. Each of these 4-HB biosynthetic pathways, their
substrates, reactants and products are described further below in
the Examples. As described herein, 4-HB can further be
biosynthetically converted to BDO by inclusion of appropriate
enzymes to produce BDO (see Example). Thus, it is understood that a
4-HB pathway can be used with enzymes for converting 4-HB to BDO to
generate a BDO pathway.
[0141] The non-naturally occurring microbial organisms of the
invention can be produced by introducing expressible nucleic acids
encoding one or more of the enzymes participating in one or more
4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathways.
Depending on the host microbial organism chosen for biosynthesis,
nucleic acids for some or all of a particular 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine biosynthetic pathway can be expressed.
For example, if a chosen host is deficient in one or more enzymes
in a desired biosynthetic pathway, for example, the succinate to
4-HB pathway, then expressible nucleic acids for the deficient
enzyme(s), for example, both CoA-independent succinic semialdehyde
dehydrogenase and 4-hydroxybutanoate dehydrogenase in this example,
are introduced into the host for subsequent exogenous expression.
Alternatively, if the chosen host exhibits endogenous expression of
some pathway enzymes, but is deficient in others, then an encoding
nucleic acid is needed for the deficient enzyme(s) to achieve 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine biosynthesis. For example, if
the chosen host exhibites endogenous CoA-independent succinic
semialdehyde dehydrogenase, but is deficient in 4-hydroxybutanoate
dehydrogenase, then an encoding nucleic acid is needed for this
enzyme to achieve 4-HB biosynthesis. Thus, a non-naturally
occurring microbial organism of the invention can be produced by
introducing exogenous enzyme or protein activities to obtain a
desired biosynthetic pathway or a desired biosynthetic pathway can
be obtained by introducing one or more exogenous enzyme or protein
activities that, together with one or more endogenous enzymes or
proteins, produces a desired product such as 4-HB, 4-HBal, 4-HBCoA,
BDO and/or putrescine.
[0142] In like fashion, where 4-HB biosynthesis is selected to
occur through the succinate to succinyl-CoA pathway (the
succinyl-CoA pathway), encoding nucleic acids for host deficiencies
in the enzymes succinyl-CoA synthetase, CoA-dependent succinic
semialdehyde dehydrogenase and/or 4-hydroxybutanoate dehydrogenase
are to be exogenously expressed in the recipient host. Selection of
4-HB biosynthesis through the .alpha.-ketoglutarate to succinic
semialdehyde pathway (the .alpha.-ketoglutarate pathway) can
utilize exogenous expression for host deficiencies in one or more
of the enzymes for glutamate:succinic semialdehyde transaminase,
glutamate decarboxylase and/or 4-hydroxybutanoate dehydrogenase, or
.alpha.-ketoglutarate decarboxylase and 4-hydroxybutanoate
dehydrogenase. One skilled in the art can readily determine pathway
enzymes for production of 4-HB or BDO, as disclosed herein.
[0143] Depending on the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
biosynthetic pathway constituents of a selected host microbial
organism, the non-naturally occurring microbial organisms of the
invention will include at least one exogenously expressed 4-HB,
4-HB, 4-HBCoA, BDO or putrescine pathway-encoding nucleic acid and
up to all encoding nucleic acids for one or more 4-HB or BDO
biosynthetic pathways. For example, 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine biosynthesis can be established in a host deficient in a
pathway enzyme or protein through exogenous expression of the
corresponding encoding nucleic acid. In a host deficient in all
enzymes or proteins of a 4-HB, 4-HB, 4-HBCoA, BDO or putrescine
pathway, exogenous expression of all enzyme or proteins in the
pathway can be included, although it is understood that all enzymes
or proteins of a pathway can be expressed even if the host contains
at least one of the pathway enzymes or proteins. For example, 4-HB
biosynthesis can be established from all five pathways in a host
deficient in 4-hydroxybutanoate dehydrogenase through exogenous
expression of a 4-hydroxybutanoate dehydrogenase encoding nucleic
acid. In contrast, 4-HB biosynthesis can be established from all
five pathways in a host deficient in all eight enzymes through
exogenous expression of all eight of CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, glutamate: succinic
semialdehyde transaminase, glutamate decarboxylase,
.alpha.-ketoglutarate decarboxylase, .alpha.-ketoglutarate
dehydrogenase and 4-hydroxybutanoate dehydrogenase.
[0144] Given the teachings and guidance provided herein, those
skilled in the art will understand that the number of encoding
nucleic acids to introduce in an expressible form will, at least,
parallel the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway
deficiencies of the selected host microbial organism. Therefore, a
non-naturally occurring microbial organism of the invention can
have one, two, three, four, five, six, seven, eight or up to all
nucleic acids encoding the enzymes disclosed herein constituting
one or more 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic
pathways. In some embodiments, the non-naturally occurring
microbial organisms also can include other genetic modifications
that facilitate or optimize 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine biosynthesis or that confer other useful functions onto
the host microbial organism. One such other functionality can
include, for example, augmentation of the synthesis of one or more
of the 4-HB pathway precursors such as succinate, succinyl-CoA,
.alpha.-ketoglutarate, 4-aminobutyrate, glutamate, acetoacetyl-CoA,
and/or homoserine.
[0145] Generally, a host microbial organism is selected such that
it produces the precursor of a 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathway, either as a naturally produced molecule or as
an engineered product that either provides de novo production of a
desired precursor or increased production of a precursor naturally
produced by the host microbial organism. For example, succinyl-CoA,
.alpha.-ketoglutarate, 4-aminobutyrate, glutamate, acetoacetyl-CoA,
and homoserine are produced naturally in a host organism such as E.
coli. A host organism can be engineered to increase production of a
precursor, as disclosed herein. In addition, a microbial organism
that has been engineered to produce a desired precursor can be used
as a host organism and further engineered to express enzymes or
proteins of a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway.
[0146] In some embodiments, a non-naturally occurring microbial
organism of the invention is generated from a host that contains
the enzymatic capability to synthesize 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine. In this specific embodiment it can be useful to
increase the synthesis or accumulation of a 4-HB, 4-HBal, 4-HBCoA,
BDO or putrescine pathway product to, for example, drive 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine pathway reactions toward 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine production. Increased synthesis
or accumulation can be accomplished by, for example, overexpression
of nucleic acids encoding one or more of the 4-HB, 4-HBal, 4-HBCoA,
BDO or putrescine pathway enzymes disclosed herein. Over expression
of the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway enzyme or
enzymes can occur, for example, through exogenous expression of the
endogenous gene or genes, or through exogenous expression of the
heterologous gene or genes. Therefore, naturally occurring
organisms can be readily generated to be non-naturally 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine producing microbial organisms of
the invention through overexpression of one, two, three, four,
five, six and so forth up to all nucleic acids encoding 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway enzymes. In
addition, a non-naturally occurring organism can be generated by
mutagenesis of an endogenous gene that results in an increase in
activity of an enzyme in the 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine biosynthetic pathway.
[0147] In particularly useful embodiments, exogenous expression of
the encoding nucleic acids is employed. Exogenous expression
confers the ability to custom tailor the expression and/or
regulatory elements to the host and application to achieve a
desired expression level that is controlled by the user. However,
endogenous expression also can be utilized in other embodiments
such as by removing a negative regulatory effector or induction of
the gene's promoter when linked to an inducible promoter or other
regulatory element. Thus, an endogenous gene having a naturally
occurring inducible promoter can be up-regulated by providing the
appropriate inducing agent, or the regulatory region of an
endogenous gene can be engineered to incorporate an inducible
regulatory element, thereby allowing the regulation of increased
expression of an endogenous gene at a desired time. Similarly, an
inducible promoter can be included as a regulatory element for an
exogenous gene introduced into a non-naturally occurring microbial
organism (see Examples).
[0148] "Exogenous" as it is used herein is intended to mean that
the referenced molecule or the referenced activity is introduced
into the host microbial organism. The molecule can be introduced,
for example, by introduction of an encoding nucleic acid into the
host genetic material such as by integration into a host chromosome
or as non-chromosomal genetic material such as a plasmid.
Therefore, the term as it is used in reference to expression of an
encoding nucleic acid refers to introduction of the encoding
nucleic acid in an expressible form into the microbial organism.
When used in reference to a biosynthetic activity, the term refers
to an activity that is introduced into the host reference organism.
The source can be, for example, a homologous or heterologous
encoding nucleic acid that expresses the referenced activity
following introduction into the host microbial organism. Therefore,
the term "endogenous" refers to a referenced molecule or activity
that is present in the host. Similarly, the term when used in
reference to expression of an encoding nucleic acid refers to
expression of an encoding nucleic acid contained within the
microbial organism. The term "heterologous" refers to a molecule or
activity derived from a source other than the referenced species
whereas "homologous" refers to a molecule or activity derived from
the host microbial organism. Accordingly, exogenous expression of
an encoding nucleic acid of the invention can utilize either or
both a heterologous or homologous encoding nucleic acid.
[0149] It is understood that when more than one exogenous nucleic
acid is included in a microbial organism that the more than one
exogenous nucleic acids refers to the referenced encoding nucleic
acid or biosynthetic activity, as discussed above. It is further
understood, as disclosed herein, that such more than one exogenous
nucleic acids can be introduced into the host microbial organism on
separate nucleic acid molecules, on polycistronic nucleic acid
molecules, or a combination thereof, and still be considered as
more than one exogenous nucleic acid. For example, as disclosed
herein a microbial organism can be engineered to express two or
more exogenous nucleic acids encoding a desired pathway enzyme or
protein. In the case where two exogenous nucleic acids encoding a
desired activity are introduced into a host microbial organism, it
is understood that the two exogenous nucleic acids can be
introduced as a single nucleic acid, for example, on a single
plasmid, on separate plasmids, can be integrated into the host
chromosome at a single site or multiple sites, and still be
considered as two exogenous nucleic acids. Similarly, it is
understood that more than two exogenous nucleic acids can be
introduced into a host organism in any desired combination, for
example, on a single plasmid, on separate plasmids, can be
integrated into the host chromosome at a single site or multiple
sites, and still be considered as two or more exogenous nucleic
acids, for example three exogenous nucleic acids. Thus, the number
of referenced exogenous nucleic acids or biosynthetic activities
refers to the number of encoding nucleic acids or the number of
biosynthetic activities, not the number of separate nucleic acids
introduced into the host organism.
[0150] Sources of encoding nucleic acids for a 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine pathway enzyme can include, for example,
any species where the encoded gene product is capable of catalyzing
the referenced reaction. Such species include both prokaryotic and
eukaryotic organisms including, but not limited to, bacteria,
including archaea and eubacteria, and eukaryotes, including yeast,
plant, insect, animal, and mammal, including human. Exemplary
species for such sources include, for example, Escherichia coli,
Saccharomyces cerevisiae, Saccharomyces kluyveri, Clostridium
kluyveri, Clostridium acetobutylicum, Clostridium beijerinckii,
Clostridium saccharoperbutylacetonicum, Clostridium perfringens,
Clostridium difficile, Clostridium botulinum, Clostridium
tyrobutyricum, Clostridium tetanomorphum, Clostridium tetani,
Clostridium propionicum, Clostridium aminobutyricum, Clostridium
subterminale, Clostridium sticklandii, Ralstonia eutropha,
Mycobacterium bovis, Mycobacterium tuberculosis, Porphyromonas
gingivalis, Arabidopsis thaliana, Thermus thermophilus, Pseudomonas
species, including Pseudomonas aeruginosa, Pseudomonas putida,
Pseudomonas stutzeri, Pseudomonas fluorescens, Homo sapiens,
Oryctolagus cuniculus, Rhodobacter spaeroides, Thermoanaerobacter
brockii, Metallosphaera sedula, Leuconostoc mesenteroides,
Chloroflexus aurantiacus, Roseiflexus castenholzii, Erythrobacter,
Simmondsia chinensis, Acinetobacter species, including
Acinetobacter calcoaceticus and Acinetobacter baylyi, Porphyromonas
gingivalis, Sulfolobus tokodaii, Sulfolobus solfataricus,
Sulfolobus acidocaldarius, Bacillus subtilis, Bacillus cereus,
Bacillus megaterium, Bacillus brevis, Bacillus pumilus, Rattus
norvegicus, Klebsiella pneumonia, Klebsiella oxytoca, Euglena
gracilis, Treponema denticola, Moorella thermoacetica, Thermotoga
maritima, Halobacterium salinarum, Geobacillus stearothermophilus,
Aeropyrum pernix, Sus scrofa, Caenorhabditis elegans,
Corynebacterium glutamicum, Acidaminococcus fermentans, Lactococcus
lactis, Lactobacillus plantarum, Streptococcus thermophilus,
Enterobacter aerogenes, Candida, Aspergillus terreus, Pedicoccus
pentosaceus, Zymomonas mobilus, Acetobacter pasteurians,
Kluyveromyces lactis, Eubacterium barkeri, Bacteroides capillosus,
Anaerotruncus colihominis, Natranaerobius thermophilusm,
Campylobacter jejuni, Haemophilus influenzae, Serratia marcescens,
Citrobacter amalonaticus, Myxococcus xanthus, Fusobacterium
nuleatum, Penicillium chrysogenum, marine gamma proteobacterium,
butyrate-producing bacterium, Nocardia iowensis, Nocardia
farcinica, Streptomyces griseus, Schizosaccharomyces pombe,
Geobacillus thermoglucosidasius, Salmonella typhimurium, Vibrio
cholera, Heliobacter pylori, Nicotiana tabacum, Oryza sativa,
Haloferax mediterranei, Agrobacterium tumefaciens, Achromobacter
denitrificans, Fusobacterium nucleatum, Streptomyces clavuligenus,
Acinetobacter baumanii, Mus musculus, Lachancea kluyveri,
Trichomonas vaginalis, Trypanosoma brucei, Pseudomonas stutzeri,
Bradyrhizobium japonicum, Mesorhizobium loti, Bos taurus, Nicotiana
glutinosa, Vibrio vulnificus, Selenomonas ruminantium, Vibrio
parahaemolyticus, Archaeoglobus fulgidus, Haloarcula marismortui,
Pyrobaculum aerophilum, Mycobacterium smegmatis MC2 155,
Mycobacterium avium subsp. paratuberculosis K-10, Mycobacterium
marinum M, Tsukamurella paurometabola DSM 20162, Cyanobium PCC7001,
Dictyostelium discoideum AX4, and others disclosed herein (see
Examples). For example, microbial organisms having 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine biosynthetic production are exemplified
herein with reference to E. coli and yeast hosts. However, with the
complete genome sequence available for now more than 550 species
(with more than half of these available on public databases such as
the NCBI), including 395 microorganism genomes and a variety of
yeast, fungi, plant, and mammalian genomes, the identification of
genes encoding the requisite 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine biosynthetic activity for one or more genes in related
or distant species, including for example, homologues, orthologs,
paralogs and nonorthologous gene displacements of known genes, and
the interchange of genetic alterations between organisms is routine
and well known in the art. Accordingly, the metabolic alterations
allowing biosynthesis of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
and other compounds of the invention described herein with
reference to a particular organism such as E. coli or yeast can be
readily applied to other microorganisms, including prokaryotic and
eukaryotic organisms alike. Given the teachings and guidance
provided herein, those skilled in the art will know that a
metabolic alteration exemplified in one organism can be applied
equally to other organisms.
[0151] In some instances, such as when an alternative 4-HB, 4-HBal,
BDO or putrescine biosynthetic pathway exists in an unrelated
species, 4-HB, 4-HBal, BDO or putrescine biosynthesis can be
conferred onto the host species by, for example, exogenous
expression of a paralog or paralogs from the unrelated species that
catalyzes a similar, yet non-identical metabolic reaction to
replace the referenced reaction. Because certain differences among
metabolic networks exist between different organisms, those skilled
in the art will understand that the actual gene usage between
different organisms may differ. However, given the teachings and
guidance provided herein, those skilled in the art also will
understand that the teachings and methods of the invention can be
applied to all microbial organisms using the cognate metabolic
alterations to those exemplified herein to construct a microbial
organism in a species of interest that will synthesize 4-HB, such
as monomeric 4-HB, 4-HBal, BDO or putrescine.
[0152] Host microbial organisms can be selected from, and the
non-naturally occurring microbial organisms generated in, for
example, bacteria, yeast, fungus or any of a variety of other
microorganisms applicable to fermentation processes. Exemplary
bacteria include species selected from Escherichia coli, Klebsiella
oxytoca, Anaerobiospirillum succiniciproducens, Actinobacillus
succinogenes, Mannheimia succiniciproducens, Rhizobium etli,
Bacillus subtilis, Corynebacterium glutamicum, Gluconobacter
oxydans, Zymomonas mobilis, Lactococcus lactis, Lactobacillus
plantarum, Streptomyces coelicolor, Clostridium acetobutylicum,
Pseudomonas fluorescens, and Pseudomonas putida. Exemplary yeasts
or fungi include species selected from Saccharomyces cerevisiae,
Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces
marxianus, Aspergillus terreus, Aspergillus niger, Pichia pastoris,
Rhizopus arrhizus, Rhizopus oryzae, and the like. E. coli is a
particularly useful host organisms since it is a well characterized
microbial organism suitable for genetic engineering. Other
particularly useful host organisms include yeast such as
Saccharomyces cerevisiae. It is understood that any suitable
microbial host organism can be used to introduce metabolic and/or
genetic modifications to produce a desired product.
[0153] Methods for constructing and testing the expression levels
of a non-naturally occurring 4-HB-, 4-HBal-, 4-HBCoA-, BDO-, or
putrescine-producing host can be performed, for example, by
recombinant and detection methods well known in the art. Such
methods can be found described in, for example, Sambrook et al.,
Molecular Cloning: A Laboratory Manual, Third Ed., Cold Spring
Harbor Laboratory, New York (2001); Ausubel et al., Current
Protocols in Molecular Biology, John Wiley and Sons, Baltimore, Md.
(1999). 4-HB and GBL can be separated by, for example, HPLC using a
Spherisorb 5 ODS1 column and a mobile phase of 70% 10 mM phosphate
buffer (pH=7) and 30% methanol, and detected using a UV detector at
215 nm (Hennessy et al. 2004, J. Forensic Sci. 46(6):1-9). BDO is
detected by gas chromatography or by HPLC and refractive index
detector using an Aminex HPX-87H column and a mobile phase of 0.5
mM sulfuric acid (Gonzalez-Pajuelo et al., Met. Eng. 7:329-336
(2005)).
[0154] Exogenous nucleic acid sequences involved in a pathway for
production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine can be
introduced stably or transiently into a host cell using techniques
well known in the art including, but not limited to, conjugation,
electroporation, chemical transformation, transduction,
transfection, and ultrasound transformation. For exogenous
expression in E. coli or other prokaryotic cells, some nucleic acid
sequences in the genes or cDNAs of eukaryotic nucleic acids can
encode targeting signals such as an N-terminal mitochondrial or
other targeting signal, which can be removed before transformation
into prokaryotic host cells, if desired. For example, removal of a
mitochondrial leader sequence led to increased expression in E.
coli (Hoffmeister et al., J. Biol. Chem. 280:4329-4338 (2005)). For
exogenous expression in yeast or other eukaryotic cells, genes can
be expressed in the cytosol without the addition of leader
sequence, or can be targeted to mitochondrion or other organelles,
or targeted for secretion, by the addition of a suitable targeting
sequence such as a mitochondrial targeting or secretion signal
suitable for the host cells. Thus, it is understood that
appropriate modifications to a nucleic acid sequence to remove or
include a targeting sequence can be incorporated into an exogenous
nucleic acid sequence to impart desirable properties. Furthermore,
genes can be subjected to codon optimization with techniques well
known in the art to achieve optimized expression of the
proteins.
[0155] An expression vector or vectors can be constructed to harbor
one or more 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic
pathway and/or one or more biosynthetic encoding nucleic acids as
exemplified herein operably linked to expression control sequences
functional in the host organism. Expression vectors applicable for
use in the microbial host organisms of the invention include, for
example, plasmids, phage vectors, viral vectors, episomes and
artificial chromosomes, including vectors and selection sequences
or markers operable for stable integration into a host chromosome.
Additionally, the expression vectors can include one or more
selectable marker genes and appropriate expression control
sequences. Selectable marker genes also can be included that, for
example, provide resistance to antibiotics or toxins, complement
auxotrophic deficiencies, or supply critical nutrients not in the
culture media. Expression control sequences can include
constitutive and inducible promoters, transcription enhancers,
transcription terminators, and the like which are well known in the
art. When two or more exogenous encoding nucleic acids are to be
co-expressed, both nucleic acids can be inserted, for example, into
a single expression vector or in separate expression vectors. For
single vector expression, the encoding nucleic acids can be
operationally linked to one common expression control sequence or
linked to different expression control sequences, such as one
inducible promoter and one constitutive promoter. The
transformation of exogenous nucleic acid sequences involved in a
metabolic or synthetic pathway can be confirmed using methods well
known in the art. Such methods include, for example, nucleic acid
analysis such as Northern blots or polymerase chain reaction (PCR)
amplification of mRNA, or immunoblotting for expression of gene
products, or other suitable analytical methods to test the
expression of an introduced nucleic acid sequence or its
corresponding gene product. It is understood by those skilled in
the art that the exogenous nucleic acid is expressed in a
sufficient amount to produce the desired product, and it is further
understood that expression levels can be optimized to obtain
sufficient expression using methods well known in the art and as
disclosed herein.
[0156] The non-naturally occurring microbial organisms of the
invention are constructed using methods well known in the art as
exemplified herein to exogenously express at least one nucleic acid
encoding a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway enzyme
in sufficient amounts to produce 4-HB, such as monomeric 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine. It is understood that the
microbial organisms of the invention are cultured under conditions
sufficient to produce 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine.
Exemplary levels of expression for 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine enzymes in each pathway are described further below in
the Examples. Following the teachings and guidance provided herein,
the non-naturally occurring microbial organisms of the invention
can achieve biosynthesis of 4-HB, such as monomeric 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine resulting in intracellular
concentrations between about 0.1-200 mM or more, for example,
0.1-25 mM or more. Generally, the intracellular concentration of
4-HB, such as monomeric 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine is
between about 3-150 mM or more, particularly about 5-125 mM or
more, and more particularly between about 8-100 mM, for example,
about 3-20 mM, particularly between about 5-15 mM and more
particularly between about 8-12 mM, including about 10 mM, 20 mM,
50 MM, 80 mM or more. Intracellular concentrations between and
above each of these exemplary ranges also can be achieved from the
non-naturally occurring microbial organisms of the invention. In
particular embodiments, the microbial organisms of the invention,
particularly strains such as those disclosed herein (see Examples
XII-XIX and Table 28), can provide improved production of a desired
product such as 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine by
increasing the production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine and/or decreasing undesirable byproducts. Such
production levels include, but are not limited to, those disclosed
herein and including from about 1 gram to about 25 grams per liter,
for example about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, or even higher amounts of
product per liter.
[0157] In addition to the culturing and fermentation conditions
disclosed herein, growth condition for achieving biosynthesis of
BDO, 4-HB, 4-HBCoA, 4-HBal and/or putrescine can include the
addition of an osmoprotectant to the culturing conditions. In
certain embodiments, the non-naturally occurring microbial
organisms of the invention can be sustained, cultured or fermented
as described herein in the presence of an osmoprotectant. Briefly,
an osmoprotectant refers to a compound that acts as an osmolyte and
helps a microbial organism as described herein survive osmotic
stress. Osmoprotectants include, but are not limited to, betaines,
amino acids, and the sugar trehalose. Non-limiting examples of such
are glycine betaine, praline betaine, dimethylthetin, dimethyl
slfonioproprionate, 3-dimethylsulfonio-2-methylproprionate,
pipecolic acid, dimethylsulfonioacetate, choline, L-carnitine and
ectoine. In one aspect, the osmoprotectant is glycine betaine. It
is understood to one of ordinary skill in the art that the amount
and type of osmoprotectant suitable for protecting a microbial
organism described herein from osmotic stress will depend on the
microbial organism used. The amount of osmoprotectant in the
culturing conditions can be, for example, no more than about 0.1
mM, no more than about 0.5 mM, no more than about 1.0 mM, no more
than about 1.5 mM, no more than about 2.0 mM, no more than about
2.5 mM, no more than about 3.0 mM, no more than about 5.0 mM, no
more than about 7.0 mM, no more than about 10 mM, no more than
about 50 mM, no more than about 100 mM or no more than about 500
mM.
[0158] In some embodiments, culture conditions include anaerobic or
substantially anaerobic growth or maintenance conditions. Exemplary
anaerobic conditions have been described previously and are well
known in the art. Exemplary anaerobic conditions for fermentation
processes are described herein and are described, for example, in
U.S. publication 2009/0047719, filed Aug. 10, 2007. Any of these
conditions can be employed with the non-naturally occurring
microbial organisms as well as other anaerobic conditions well
known in the art. Under such anaerobic conditions, the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine producers can synthesize 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine at intracellular concentrations
of 5-10 mM or more as well as all other concentrations exemplified
herein. It is understood that, even though the above description
refers to intracellular concentrations, 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine producing microbial organisms can produce 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine intracellularly and/or secrete
the product into the culture medium.
[0159] The culture conditions can include, for example, liquid
culture procedures as well as fermentation and other large scale
culture procedures. As described herein, particularly useful yields
of the biosynthetic products of the invention can be obtained under
anaerobic or substantially anaerobic culture conditions.
[0160] As described herein, one exemplary growth condition for
achieving biosynthesis of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
includes anaerobic culture or fermentation conditions. In certain
embodiments, the non-naturally occurring microbial organisms of the
invention can be sustained, cultured or fermented under anaerobic
or substantially anaerobic conditions. Briefly, anaerobic
conditions refers to an environment devoid of oxygen. Substantially
anaerobic conditions include, for example, a culture, batch
fermentation or continuous fermentation such that the dissolved
oxygen concentration in the medium remains between 0 and 10% of
saturation. Substantially anaerobic conditions also includes
growing or resting cells in liquid medium or on solid agar inside a
sealed chamber maintained with an atmosphere of less than 1%
oxygen. The percent of oxygen can be maintained by, for example,
sparging the culture with an N.sub.2/CO.sub.2 mixture or other
suitable non-oxygen gas or gases.
[0161] The invention also provides a non-naturally occurring
microbial biocatalyst including a microbial organism having
4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic
pathways that include at least one exogenous nucleic acid encoding
4-hydroxybutanoate dehydrogenase, CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA
transferase, glutamate: succinic semialdehyde transaminase,
glutamate decarboxylase, CoA-independent aldehyde dehydrogenase,
CoA-dependent aldehyde dehydrogenase or alcohol dehydrogenase,
wherein the exogenous nucleic acid is expressed in sufficient
amounts to produce 1,4-butanediol (BDO). 4-Hydroxybutyrate:CoA
transferase also is known as 4-hydroxybutyryl CoA:acetyl-CoA
transferase. Additional 4-HB or BDO pathway enzymes are also
disclosed herein (see Examples and FIGS. 8-13).
[0162] The invention further provides non-naturally occurring
microbial biocatalyst including a microbial organism having
4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic
pathways, the pathways include at least one exogenous nucleic acid
encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase,
CoA-dependent succinic semialdehyde dehydrogenase,
4-hydroxybutyrate:CoA transferase, 4-butyrate kinase,
phosphotransbutyrylase, .alpha.-ketoglutarate decarboxylase,
aldehyde dehydrogenase, alcohol dehydrogenase or an
aldehyde/alcohol dehydrogenase, wherein the exogenous nucleic acid
is expressed in sufficient amounts to produce 1,4-butanediol
(BDO).
[0163] Non-naturally occurring microbial organisms also can be
generated which biosynthesize BDO. As with the 4-HB producing
microbial organisms of the invention, the BDO producing microbial
organisms also can produce intracellularly or secret the BDO into
the culture medium. Following the teachings and guidance provided
previously for the construction of microbial organisms that
synthesize 4-HB, additional BDO pathways can be incorporated into
the 4-HB producing microbial organisms to generate organisms that
also synthesize BDO and other BDO family compounds. The chemical
synthesis of BDO and its downstream products are known. The
non-naturally occurring microbial organisms of the invention
capable of BDO biosynthesis circumvent these chemical synthesis
using 4-HB as an entry point as illustrated in FIG. 1. As described
further below, the 4-HB producers also can be used to chemically
convert 4-HB to GBL and then to BDO or THF, for example.
Alternatively, the 4-HB producers can be further modified to
include biosynthetic capabilities for conversion of 4-HB and/or GBL
to BDO.
[0164] The additional BDO pathways to introduce into 4-HB producers
include, for example, the exogenous expression in a host deficient
background or the overexpression of one or more of the enzymes
exemplified in FIG. 1 as steps 9-13. One such pathway includes, for
example, the enzyme activies necessary to carryout the reactions
shown as steps 9, 12 and 13 in FIG. 1, where the aldehyde and
alcohol dehydrogenases can be separate enzymes or a multifunctional
enzyme having both aldehyde and alcohol dehydrogenase activity.
Another such pathway includes, for example, the enzyme activities
necessary to carry out the reactions shown as steps 10, 11, 12 and
13 in FIG. 1, also where the aldehyde and alcohol dehydrogenases
can be separate enzymes or a multifunctional enzyme having both
aldehyde and alcohol dehydrogenase activity. Accordingly, the
additional BDO pathways to introduce into 4-HB producers include,
for example, the exogenous expression in a host deficient
background or the overexpression of one or more of a
4-hydroxybutyrate:CoA transferase, butyrate kinase,
phosphotransbutyrylase, CoA-independent aldehyde dehydrogenase,
CoA-dependent aldehyde dehydrogenase or an alcohol dehydrogenase.
In the absence of endogenous acyl-CoA synthetase capable of
modifying 4-HB, the non-naturally occurring BDO producing microbial
organisms can further include an exogenous acyl-CoA synthetase
selective for 4-HB, or the combination of multiple enzymes that
have as a net reaction conversion of 4-HB into 4-HB-CoA. As
exemplified further below in the Examples, butyrate kinase and
phosphotransbutyrylase exhibit BDO pathway activity and catalyze
the conversions illustrated in FIG. 1 with a 4-HB substrate.
Therefore, these enzymes also can be referred to herein as
4-hydroxybutyrate kinase and phosphotranshydroxybutyrylase
respectively.
[0165] Exemplary alcohol and aldehyde dehydrogenases that can be
used for these in vivo conversions from 4-HB to BDO are listed
below in Table 1.
TABLE-US-00001 TABLE 1 Alcohol and Aldehyde Dehydrogenases for
Conversion of 4-HB to BDO. ALCOHOL DEHYDROGENASES ec: 1.1.1.1
alcohol dehydrogenase ec: 1.1.1.2 alcohol dehydrogenase (NADP+) ec:
1.1.1.4 (R,R)-butanediol dehydrogenase ec: 1.1.1.5 acetoin
dehydrogenase ec: 1.1.1.6 glycerol dehydrogenase ec: 1.1.1.7
propanediol-phosphate dehydrogenase ec: 1.1.1.8
glycerol-3-phosphate dehydrogenase (NAD+) ec: 1.1.1.11 D-arabinitol
4-dehydrogenase ec: 1.1.1.12 L-arabinitol 4-dehydrogenase ec:
1.1.1.13 L-arabinitol 2-dehydrogenase ec: 1.1.1.14 L-iditol
2-dehydrogenase ec: 1.1.1.15 D-iditol 2-dehydrogenase ec: 1.1.1.16
galactitol 2-dehydrogenase ec: 1.1.1.17 mannitol-l-phosphate 5-
dehydrogenase ec: 1.1.1.18 inositol 2-dehydrogenase ec: 1.1.1.21
aldehyde reductase ec: 1.1.1.23 histidinol dehydrogenase ec:
1.1.1.26 glyoxylate reductase ec: 1.1.1.27 L-lactate dehydrogenase
ec: 1.1.1.28 D-lactate dehydrogenase ec: 1.1.1.29 glycerate
dehydrogenase ec: 1.1.1.30 3-hydroxybutyrate dehydrogenase ec:
1.1.1.31 3-hydroxyisobutyrate dehydrogenase ec: 1.1.1.35
3-hydroxyacyl-CoA dehydrogenase ec: 1.1.1.36 acetoacetyl-CoA
reductase ec: 1.1.1.37 malate dehydrogenase ec: 1.1.1.38 malate
dehydrogenase (oxaloacetate- decarboxylating) ec: 1.1.1.39 malate
dehydrogenase (decarboxylating) ec: 1.1.1.40 malate dehydrogenase
(oxaloacetate- decarboxylating) (NADP+) ec: 1.1.1.41 isocitrate
dehydrogenase (NAD+) ec: 1.1.1.42 isocitrate dehydrogenase (NADP+)
ec: 1.1.1.54 allyl-alcohol dehydrogenase ec: 1.1.1.55 lactaldehyde
reductase (NADPH) ec: 1.1.1.56 ribitol 2-dehydrogenase ec: 1.1.1.59
3-hydroxypropionate dehydrogenase ec: 1.1.1.60
2-hydroxy-3-oxopropionate reductase ec: 1.1.1.61 4-hydroxybutyrate
dehydrogenase ec: 1.1.1.66 omega-hydroxydecanoate dehydrogenase ec:
1.1.1.67 mannitol 2-dehydrogenase ec: 1.1.1.71 alcohol
dehydrogenase [NAD(P)+] ec: 1.1.1.72 glycerol dehydrogenase (NADP+)
ec: 1.1.1.73 octanol dehydrogenase ec: 1.1.1.75 (R)-aminopropanol
dehydrogenase ec: 1.1.1.76 (S,S)-butanediol dehydrogenase ec:
1.1.1.77 lactaldehyde reductase ec: 1.1.1.78 methylglyoxal
reductase (NADH- dependent) ec: 1.1.1.79 glyoxylate reductase
(NADP+) ec: 1.1.1.80 isopropanol dehydrogenase (NADP+) ec: 1.1.1.81
hydroxypyruvate reductase ec: 1.1.1.82 malate dehydrogenase (NADP+)
ec: 1.1.1.83 D-malate dehydrogenase (decarboxylating) ec: 1.1.1.84
dimethylmalate dehydrogenase ec: 1.1.1.85 3-isopropylmalate
dehydrogenase ec: 1.1.1.86 ketol-acid reductoisomerase ec: 1.1.1.87
homoisocitrate dehydrogenase ec: 1.1.1.88 hydroxymethylglutaryl-CoA
reductase ec: 1.1.1.90 aryl-alcohol dehydrogenase ec: 1.1.1.91
aryl-alcohol dehydrogenase (NADP+) ec: 1.1.1.92 oxaloglycolate
reductase (decarboxylating) ec: 1.1.1.94 glycerol-3-phosphate
dehydrogenase [NAD(P)+] ec: 1.1.1.95 phosphoglycerate dehydrogenase
ec: 1.1.1.97 3-hydroxybenzyl-alcohol dehydrogenase ec: 1.1.1.101
acylglycerone-phosphate reductase ec: 1.1.1.103 L-threonine
3-dehydrogenase ec: 1.1.1.104 4-oxoproline reductase ec: 1.1.1.105
retinol dehydrogenase ec: 1.1.1.110 indolelactate dehydrogenase ec:
1.1.1.112 indanol dehydrogenase ec: 1.1.1.113 L-xylose
1-dehydrogenase ec: 1.1.1.129 L-threonate 3-dehydrogenase ec:
1.1.1.137 ribitol-5-phosphate 2-dehydrogenase ec: 1.1.1.138
mannitol 2-dehydrogenase (NADP+) ec: 1.1.1.140 sorbitol-6-phosphate
2- dehydrogenase ec: 1.1.1.142 D-pinitol dehydrogenase ec:
1.1.1.143 sequoyitol dehydrogenase ec: 1.1.1.144 perillyl-alcohol
dehydrogenase ec: 1.1.1.156 glycerol 2-dehydrogenase (NADP+) ec:
1.1.1.157 3-hydroxybutyryl-CoA dehydrogenase ec: 1.1.1.163
cyclopentanol dehydrogenase ec: 1.1.1.164 hexadecanol dehydrogenase
ec: 1.1.1.165 2-alkyn-1-ol dehydrogenase ec: 1.1.1.166
hydroxycyclohexanecarboxylate dehydrogenase ec: 1.1.1.167
hydroxymalonate dehydrogenase ec: 1.1.1.174 cyclohexane-1,2-diol
dehydrogenase ec: 1.1.1.177 glycerol-3-phosphate 1- dehydrogenase
(NADP+) ec: 1.1.1.178 3-hydroxy-2-methylbutyryl-CoA dehydrogenase
ec: 1.1.1.185 L-glycol dehydrogenase ec: 1.1.1.190
indole-3-acetaldehyde reductase (NADH) ec: 1.1.1.191
indole-3-acetaldehyde reductase (NADPH) ec: 1.1.1.192
long-chain-alcohol dehydrogenase ec: 1.1.1.194 coniferyl-alcohol
dehydrogenase ec: 1.1.1.195 cinnamyl-alcohol dehydrogenase ec:
1.1.1.198 (+)-borneol dehydrogenase ec: 1.1.1.202 1,3-propanediol
dehydrogenase ec: 1.1.1.207 (-)-menthol dehydrogenase ec: 1.1.1.208
(+)-neomenthol dehydrogenase ec: 1.1.1.216 farnesol dehydrogenase
ec: 1.1.1.217 benzyl-2-methyl-hydroxybutyrate dehydrogenase ec:
1.1.1.222 (R)-4-hydroxyphenyllactate dehydrogenase ec: 1.1.1.223
isopiperitenol dehydrogenase ec: 1.1.1.226
4-hydroxycyclohexanecarboxylate dehydrogenase ec: 1.1.1.229 diethyl
2-methyl-3-oxosuccinate reductase ec: 1.1.1.237
hydroxyphenylpyruvate reductase ec: 1.1.1.244 methanol
dehydrogenase ec: 1.1.1.245 cyclohexanol dehydrogenase ec:
1.1.1.250 D-arabinitol 2-dehydrogenase ec: 1.1.1.251 galactitol
1-phosphate 5- dehydrogenase ec: 1.1.1.255 mannitol dehydrogenase
ec: 1.1.1.256 fluoren-9-ol dehydrogenase ec: 1.1.1.257
4-(hydroxymethyl)benzenesulfonate dehydrogenase ec: 1.1.1.258
6-hydroxyhexanoate dehydrogenase ec: 1.1.1.259
3-hydroxypimeloyl-CoA dehydrogenase ec: 1.1.1.261
glycerol-1-phosphate dehydrogenase [NAD(P)+] ec: 1.1.1.265
3-methylbutanal reductase ec: 1.1.1.283 methylglyoxal reductase
(NADPH- dependent) ec: 1.1.1.286 isocitrate-homoisocitrate
dehydrogenase ec: 1.1.1.287 D-arabinitol dehydrogenase (NADP+)
butanol dehydrogenase ALDEHYDE DEHYDROGENASES ec: 1.2.1.2 formate
dehydrogenase ec: 1.2.1.3 aldehyde dehydrogenase (NAD+) ec: 1.2.1.4
aldehyde dehydrogenase (NADP+) ec: 1.2.1.5 aldehyde dehydrogenase
[NAD(P)+] ec: 1.2.1.7 benzaldehyde dehydrogenase (NADP+) ec:
1.2.1.8 betaine-aldehyde dehydrogenase ec: 1.2.1.9
glyceraldehyde-3-phosphate dehydrogenase (NADP+) ec: 1.2.1.10
acetaldehyde dehydrogenase (acetylating) ec: 1.2.1.11
aspartate-semialdehyde dehydrogenase ec: 1.2.1.12
glyceraldehyde-3-phosphate dehydrogenase (phosphorylating) ec:
1.2.1.13 glyceraldehyde-3-phosphate dehydrogenase (NADP+)
(phosphorylating) ec: 1.2.1.15 malonate-semialdehyde dehydrogenase
ec: 1.2.1.16 succinate-semialdehyde dehydrogenase [NAD(P)+] ec:
1.2.1.17 glyoxylate dehydrogenase (acylating) ec: 1.2.1.18
malonate-semialdehyde dehydrogenase (acetylating) ec: 1.2.1.19
aminobutyraldehyde dehydrogenase ec: 1.2.1.20
glutarate-semialdehyde dehydrogenase ec: 1.2.1.21 glycolaldehyde
dehydrogenase ec: 1.2.1.22 lactaldehyde dehydrogenase ec: 1.2.1.23
2-oxoaldehyde dehydrogenase (NAD+) ec: 1.2.1.24
succinate-semialdehyde dehydrogenase ec: 1.2.1.25 2-oxoisovalerate
dehydrogenase (acylating) ec: 1.2.1.26 2,5-dioxovalerate
dehydrogenase ec: 1.2.1.27 methylmalonate-semialdehyde
dehydrogenase (acylating) ec: 1.2.1.28 benzaldehyde dehydrogenase
(NAD+) ec: 1.2.1.29 aryl-aldehyde dehydrogenase ec: 1.2.1.30
aryl-aldehyde dehydrogenase (NADP+) ec: 1.2.1.31
L-aminoadipate-semialdehyde dehydrogenase ec: 1.2.1.32
aminomuconate-semialdehyde dehydrogenase ec: 1.2.1.36 retinal
dehydrogenase ec: 1.2.1.39 phenylacetaldehyde dehydrogenase ec:
1.2.1.41 glutamate-5-semialdehyde dehydrogenase ec: 1.2.1.42
hexadecanal dehydrogenase (acylating) ec: 1.2.1.43 formate
dehydrogenase (NADP+) ec: 1.2.1.45 4-carboxy-2-hydroxymuconate-6-
semialdehyde dehydrogenase ec: 1.2.1.46 formaldehyde dehydrogenase
ec: 1.2.1.47 4-trimethylammoniobutyraldehyde dehydrogenase ec:
1.2.1.48 long-chain-aldehyde dehydrogenase ec: 1.2.1.49
2-oxoaldehyde dehydrogenase (NADP+) ec: 1.2.1.51 pyruvate
dehydrogenase (NADP+) ec: 1.2.1.52 oxoglutarate dehydrogenase
(NADP+) ec: 1.2.1.53 4-hydroxyphenylacetaldehyde dehydrogenase ec:
1.2.1.57 butanal dehydrogenase ec: 1.2.1.58 phenylglyoxylate
dehydrogenase (acylating) ec: 1.2.1.59 glyceraldehyde-3-phosphate
dehydrogenase (NAD(P)+) (phosphorylating) ec: 1.2.1.62
4-formylbenzenesulfonate dehydrogenase ec: 1.2.1.63 6-oxohexanoate
dehydrogenase ec: 1.2.1.64 4-hydroxybenzaldehyde dehydrogenase ec:
1.2.1.65 salicylaldehyde dehydrogenase ec: 1.2.1.66
mycothiol-dependent formaldehyde dehydrogenase ec: 1.2.1.67
vanillin dehydrogenase ec: 1.2.1.68 coniferyl-aldehyde
dehydrogenase ec: 1.2.1.69 fluoroacetaldehyde dehydrogenase ec:
1.2.1.71 succinylglutamate-semialdehyde dehydrogenase
[0166] Other exemplary enzymes and pathways are disclosed herein
(see Examples). Furthermore, it is understood that enzymes can be
utilized for carry out reactions for which the substrate is not the
natural substrate. While the activity for the non-natural substrate
may be lower than the natural substrate, it is understood that such
enzymes can be utilized, either as naturally occurring or modified
using the directed evolution or adaptive evolution, as disclosed
herein (see also Examples).
[0167] BDO production through any of the pathways disclosed herein
are based, in part, on the identification of the appropriate
enzymes for conversion of precursors to BDO. A number of specific
enzymes for several of the reaction steps have been identified. For
those transformations where enzymes specific to the reaction
precursors have not been identified, enzyme candidates have been
identified that are best suited for catalyzing the reaction steps.
Enzymes have been shown to operate on a broad range of substrates,
as discussed below. In addition, advances in the field of protein
engineering also make it feasible to alter enzymes to act
efficiently on substrates, even if not a natural substrate.
Described below are several examples of broad-specificity enzymes
from diverse classes suitable for a BDO pathway as well as methods
that have been used for evolving enzymes to act on non-natural
substrates.
[0168] A key class of enzymes in BDO pathways is the
oxidoreductases that interconvert ketones or aldehydes to alcohols
(1.1.1). Numerous exemplary enzymes in this class can operate on a
wide range of substrates. An alcohol dehydrogenase (1.1.1.1)
purified from the soil bacterium Brevibacterium sp KU 1309 (Hirano
et al., J. Biosc. Bioeng. 100:318-322 (2005)) was shown to operate
on a plethora of aliphatic as well as aromatic alcohols with high
activities. Table 2 shows the activity of the enzyme and its
K.sub.m on different alcohols. The enzyme is reversible and has
very high activity on several aldehydes also (Table 3).
TABLE-US-00002 TABLE 2 Relative activities of an alcohol
dehydrogenase from Brevibacterium sp KU to oxidize various
alcohols. Relative Activity K.sub.m Substrate (0%) (mM)
2-Phenylethanol 100* 0.025 (S)-2-Phenylpropanol 156 0.157
(R)-2-Phenylpropanol 63 0.020 Bynzyl alcohol 199 0.012
3-Phenylpropanol 135 0.033 Ethanol 76 1-Butanol 111 1-Octanol 101
1-Dodecanol 68 1-Phenylethanol 46 2-Propanol 54 *The activity of
2-phenylethanol, corresponding to 19.2 U/mg, was taken as 100%.
TABLE-US-00003 TABLE 3 Relative activities of an alcohol
dehydrogenase from Brevibacterium sp KU 1309 to reduce various
carbonyl compounds. Relative Activity K.sub.m Substrate (%) (mM)
Phenylacetaldehyde 100 0.261 2-Phenylpropionaldehyde 188 0.864
1-Octylaldehyde 87 Acetophenone 0
[0169] Lactate dehydrogenase (1.1.1.27) from Ralstonia eutropha is
another enzyme that has been demonstrated to have high activities
on several 2-oxoacids such as 2-oxobutyrate, 2-oxopentanoate and
2-oxoglutarate (a C5 compound analogous to 2-oxoadipate)
(Steinbuchel and Schlegel, Eur. J. Biochem. 130:329-334 (1983)).
Column 2 in Table 4 demonstrates the activities of ldhA from R.
eutropha (formerly A. eutrophus) on different substrates
(Steinbuchel and Schlegel, supra, 1983).
TABLE-US-00004 TABLE 4 The in vitro activity of R. eutropha ldhA
(Steinbuchel and Schlegel, supra, 1983) on different substrates and
compared with that on pyruvate. Activity (%) of L(+)-lactate
L(+)-lactate D(-)-lactate dehydro- dehydro- dehydro- genase from
genase from genase from Substrate A. eutrophus rabbit muscle L.
leichmanii Glyoxylate 8.7 23.9 5.0 Pyruvate 100.0 100.0 100.0
2-Oxobutyrate 107.0 18.6 1.1 2-Oxovalerate 125.0 0.7 0.0
3-Methyl-2- 28.5 0.0 0.0 oxobutyrate 3-Methyl-2- 5.3 0.0 0.0
oxovalerate 4-Methyl-2- 39.0 1.4 1.1 oxopentanoate Oxaloacetate 0.0
33.1 23.1 2-Oxoglutarate 79.6 0.0 0.0 3-Fluoropyruvate 33.6 74.3
40.0
[0170] Oxidoreductases that can convert 2-oxoacids to their
acyl-CoA counterparts (1.2.1) have been shown to accept multiple
substrates as well. For example, branched-chain 2-keto-acid
dehydrogenase complex (BCKAD), also known as 2-oxoisovalerate
dehydrogenase (1.2.1.25), participates in branched-chain amino acid
degradation pathways, converting 2-keto acids derivatives of
valine, leucine and isoleucine to their acyl-CoA derivatives and
CO.sub.2. In some organisms including Rattus norvegicus (Paxton et
al., Biochem. J. 234:295-303 (1986)) and Saccharomyces cerevisiae
(Sinclair et al., Biochem. Mol Biol. Int. 32:911-922 (1993), this
complex has been shown to have a broad substrate range that
includes linear oxo-acids such as 2-oxobutanoate and
alpha-ketoglutarate, in addition to the branched-chain amino acid
precursors.
[0171] Members of yet another class of enzymes, namely
aminotransferases (2.6.1), have been reported to act on multiple
substrates. Aspartate aminotransferase (aspAT) from Pyrococcus
fursious has been identified, expressed in E. coli and the
recombinant protein characterized to demonstrate that the enzyme
has the highest activities towards aspartate and
alpha-ketoglutarate but lower, yet significant activities towards
alanine, glutamate and the aromatic amino acids (Ward et al.,
Archaea 133-141 (2002)). In another instance, an aminotransferase
identified from Leishmania mexicana and expressed in E. coli
(Vernal et al., FEMS Microbiol. Lett. 229:217-222 (2003)) was
reported to have a broad substrate specificity towards tyrosine
(activity considered 100% on tyrosine), phenylalanine (90%),
tryptophan (85%), aspartate (30%), leucine (25%) and methionine
(25%), respectively (Vernal et al., Mol. Biochem. Parasitol
96:83-92 (1998)). Similar broad specificity has been reported for a
tyrosine aminotransferase from Trypanosoma cruzi, even though both
of these enzymes have a sequence homology of only 6%. The latter
enzyme can accept leucine, methionine as well as tyrosine,
phenylalanine, tryptophan and alanine as efficient amino donors
(Nowicki et al., Biochim. Biophys. Acta 1546: 268-281 (2001)).
[0172] CoA transferases (2.8.3) have been demonstrated to have the
ability to act on more than one substrate. Specifically, a CoA
transferase was purified from Clostridium acetobutylicum and was
reported to have the highest activities on acetate, propionate, and
butyrate. It also had significant activities with valerate,
isobutyrate, and crotonate (Wiesenborn et al., Appl. Environ.
Microbiol. 55:323-329 (1989)). In another study, the E. coli enzyme
acyl-CoA:acetate-CoA transferase, also known as acetate-CoA
transferase (EC 2.8.3.8), has been shown to transfer the CoA moiety
to acetate from a variety of branched and linear acyl-CoA
substrates, including isobutyrate (Matthies and Schink, App.
Environm. Microbiol. 58:1435-1439 (1992)), valerate (Vanderwinkel
et al., Biochem. Biophys. Res Commun. 33:902-908 (1968b)) and
butanoate (Vanderwinkel et al., Biochem. Biophys. Res Commun.
33:902-908 (1968a).
[0173] Other enzyme classes additionally support broad substrate
specificity for enzymes. Some isomerases (5.3.3) have also been
proven to operate on multiple substrates. For example, L-rhamnose
isomerase from Pseudomonas stutzeri catalyzes the isomerization
between various aldoalses and ketoses (Yoshida et al., J. Mol.
Biol. 365:1505-1516 (2007)). These include isomerization between
L-rhamnose and L-rhamnulose, L-mannose and L-fructose, L-xylose and
L-xylulose, D-ribose and D-ribulose, and D-allose and
D-psicose.
[0174] In yet another class of enzymes, the phosphotransferases
(2.7.1), the homoserine kinase (2.7.1.39) from E. coli that
converts L-homoserine to L-homoserine phosphate, was found to
phosphorylate numerous homoserine analogs. In these substrates, the
carboxyl functional group at the R-position had been replaced by an
ester or by a hydroxymethyl group (Huo and Viola, Biochemistry
35:16180-16185 (1996)). Table 5 demonstrates the broad substrate
specificity of this kinase.
TABLE-US-00005 TABLE 5 The substrate specificity of homoserine
kinase. K.sub.m Substrate k.sub.cat % k.sub.cat (mM)
k.sub.cat/K.sub.m L-homoserine 18.3 .+-. 0.1 100 0.14 .+-. 0.04 184
.+-. 17 D-homoserine 8.3 .+-. 1.1 32 31.8 .+-. 7.2 0.26 .+-. 0.03
L-aspartate 2.1 .+-. 0.1 8.2 0.28 .+-. 0.02 7.5 .+-. 0.3
.beta.-semialdehyde L-2-amino-1,4- 2.0 .+-. 0.5 7.9 11.6 .+-. 6.5
0.17 .+-. 0.06 butanediol L-2-amino-5- 2.5 .+-. 0.4 9.9 1.1 .+-.
0.5 2.3 .+-. 0.3 hydroxyvalerate L-homoserine 14.7 .+-. 2.6 80 4.9
.+-. 2.0 3.0 .+-. 0.6 methyl ester L-homoserine 13.6 .+-. 0.8 74
1.9 .+-. 0.5 7.2 .+-. 1.7 ethyl ester L-homoserine 13.6 .+-. 1.4 74
1.2 .+-. 0.5 11.3 .+-. 1.1 isopropyl ester L-homoserine 14.0 .+-.
0.4 76 3.5 .+-. 0.4 4.0 .+-. 1.2 n-propyl ester L-homoserine 16.4
.+-. 0.8 84 6.9 .+-. 1.1 2.4 .+-. 0.3 isobutyl ester L-homserine
29.1 .+-. 1.2 160 5.8 .+-. 0.8 5.0 .+-. 0.5 n-butyl ester
[0175] Another class of enzymes useful in BDO pathways is the
acid-thiol ligases (6.2.1). Like enzymes in other classes, certain
enzymes in this class have been determined to have broad substrate
specificity. For example, acyl CoA ligase from Pseudomonas putida
has been demonstrated to work on several aliphatic substrates
including acetic, propionic, butyric, valeric, hexanoic, heptanoic,
and octanoic acids and on aromatic compounds such as phenylacetic
and phenoxyacetic acids (Fernandez-Valverde et al., Appl. Environ.
Microbiol. 59:1149-1154 (1993)). A related enzyme, malonyl CoA
synthetase (6.3.4.9) from Rhizobium trifolii could convert several
diacids, namely, ethyl-, propyl-, allyl-, isopropyl-, dimethyl-,
cyclopropyl-, cyclopropylmethylene-, cyclobutyl-, and
benzyl-malonate into their corresponding monothioesters (Pohl et
al., J. Am. Chem. Soc. 123:5822-5823 (2001)). Similarly,
decarboxylases (4.1.1) have also been found with broad substrate
ranges. Pyruvate decarboxylase (PDC), also termed keto-acid
decarboxylase, is a key enzyme in alcoholic fermentation,
catalyzing the decarboxylation of pyruvate to acetaldehyde. The
enzyme isolated from Saccharomyces cerevisiae has a broad substrate
range for aliphatic 2-keto acids including 2-ketobutyrate,
2-ketovalerate, and 2-phenylpyruvate (Li and Jordan, Biochemistry
38:10004-10012 (1999)). Similarly, benzoylformate decarboxylase has
a broad substrate range and has been the target of enzyme
engineering studies. The enzyme from Pseudomonas putida has been
extensively studied and crystal structures of this enzyme are
available (Polovnikova et al., Biochemistry 42:1820-1830 (2003);
Hasson et al., Biochemistry 37:9918-9930 (1998)). Branched chain
alpha-ketoacid decarboxylase (BCKA) has been shown to act on a
variety of compounds varying in chain length from 3 to 6 carbons
(Oku and Kaneda, J. Biol. Chem. 263:18386-18396 (1998); Smit et
al., Appl. Environ. Microbiol. 71:303-311 (2005b)). The enzyme in
Lactococcus lactis has been characterized on a variety of branched
and linear substrates including 2-oxobutanoate, 2-oxohexanoate,
2-oxopentanoate, 3-methyl-2-oxobutanoate, 4-methyl-2-oxobutanoate
and isocaproate (Smit et al., Appl. Environ. Microbiol. 71:303-311
(2005a).
[0176] Interestingly, enzymes known to have one dominant activity
have also been reported to catalyze a very different function. For
example, the cofactor-dependent phosphoglycerate mutase (5.4.2.1)
from Bacillus stearothermophilus and Bacillus subtilis is known to
function as a phosphatase as well (Rigden et al., Protein Sci.
10:1835-1846 (2001)). The enzyme from B. stearothermophilus is
known to have activity on several substrates, including
3-phosphoglycerate, alpha-napthylphosphate, p-nitrophenylphosphate,
AMP, fructose-6-phosphate, ribose-5-phosphate and CMP.
[0177] In contrast to these examples where the enzymes naturally
have broad substrate specificities, numerous enzymes have been
modified using directed evolution to broaden their specificity
towards their non-natural substrates. Alternatively, the substrate
preference of an enzyme has also been changed using directed
evolution. Therefore, it is feasible to engineer a given enzyme for
efficient function on a natural, for example, improved efficiency,
or a non-natural substrate, for example, increased efficiency. For
example, it has been reported that the enantioselectivity of a
lipase from Pseudomonas aeruginosa was improved significantly
(Reetz et al., Agnew. Chem. Int. Ed Engl. 36:2830-2832 (1997)).
This enzyme hydrolyzed p-nitrophenyl 2-methyldecanoate with only 2%
enantiomeric excess (ee) in favor of the (S)-acid. However, after
four successive rounds of error-prone mutagenesis and screening, a
variant was produced that catalyzed the requisite reaction with 81%
ee (Reetz et al., Agnew. Chem. Int. Ed Engl. 36:2830-2832
(1997)).
[0178] Directed evolution methods have been used to modify an
enzyme to function on an array of non-natural substrates. The
substrate specificity of the lipase in P. aeruginosa was broadened
by randomization of amino acid residues near the active site. This
allowed for the acceptance of alpha-substituted carboxylic acid
esters by this enzyme (Reetz et al., Agnew. Chem. Int. Ed Engl.
44:4192-4196 (2005)). In another successful modification of an
enzyme, DNA shuffling was employed to create an Escherichia coli
aminotransferase that accepted .beta.-branched substrates, which
were poorly accepted by the wild-type enzyme (Yano et al., Proc.
Nat. Acad. Sci. U.S.A. 95:5511-5515 (1998)). Specifically, at the
end of four rounds of shuffling, the activity of aspartate
aminotransferase for valine and 2-oxovaline increased by up to five
orders of magnitude, while decreasing the activity towards the
natural substrate, aspartate, by up to 30-fold. Recently, an
algorithm was used to design a retro-aldolase that could be used to
catalyze the carbon-carbon bond cleavage in a non-natural and
non-biological substrate,
4-hydroxy-4-(6-methoxy-2-naphthyl)-2-butanone (Jiang et al.,
Science 319:1387-1391 (2008)). These algorithms used different
combinations of four different catalytic motifs to design new
enzyme, and 20 of the selected designs for experimental
characterization had four-fold improved rates over the uncatalyzed
reaction (Jiang et al., Science 319:1387-1391 (2008)). Thus, not
only are these engineering approaches capable of expanding the
array of substrates on which an enzyme can act, but they allow the
design and construction of very efficient enzymes. For example, a
method of DNA shuffling (random chimeragenesis on transient
templates or RACHITT) was reported to lead to an engineered
monooxygenase that had an improved rate of desulfurization on
complex substrates as well as 20-fold faster conversion of a
non-natural substrate (Coco et al., Nat. Biotechnol. 19:354-359
(2001)). Similarly, the specific activity of a sluggish mutant
triosephosphate isomerase enzyme was improved up to 19-fold from
1.3 fold (Hermes et al., Proc. Nat. Acad. Sci. U.S.A. 87:696-700
1990)). This enhancement in specific activity was accomplished by
using random mutagenesis over the whole length of the protein and
the improvement could be traced back to mutations in six amino acid
residues.
[0179] The effectiveness of protein engineering approaches to alter
the substrate specificity of an enzyme for a desired substrate has
also been demonstrated in several studies. Isopropylmalate
dehydrogenase from Thermus thermophilus was modified by changing
residues close to the active site so that it could now act on
malate and D-lactate as substrates (Fujita et al., Biosci.
Biotechnol. Biochem. 65:2695-2700 (2001)). In this study as well as
in others, it was pointed out that one or a few residues could be
modified to alter the substrate specificity. For example, the
dihydroflavonol 4-reductase for which a single amino acid was
changed in the presumed substrate-binding region could
preferentially reduce dihydrokaempferol (Johnson et al., Plant. J.
25:325-333 (2001)). The substrate specificity of a very specific
isocitrate dehydrogenase from Escherichia coli was changed form
isocitrate to isopropylmalate by changing one residue in the active
site (Doyle et al., Biochemistry 40:4234-4241 (2001)). Similarly,
the cofactor specificity of a NAD.sup.+-dependent
1,5-hydroxyprostaglandin dehydrogenase was altered to NADP.sup.+ by
changing a few residues near the N-terminal end (Cho et al., Arch.
Biochem. Biophys. 419:139-146 (2003)). Sequence analysis and
molecular modeling analysis were used to identify the key residues
for modification, which were further studied by site-directed
mutagenesis.
[0180] Numerous examples exist spanning diverse classes of enzymes
where the function of enzyme was changed to favor one non-natural
substrate over the natural substrate of the enzyme. A fucosidase
was evolved from a galactosidase in E. coli by DNA shuffling and
screening (Zhang et al., Proc. Natl Acad. Sci. U.S.A. 94:4504-4509
(1997)). Similarly, aspartate aminotransferase from E. coli was
converted into a tyrosine aminotransferase using homology modeling
and site-directed mutagenesis (Onuffer and Kirsch, Protein Sci.,
4:1750-1757 (1995)). Site-directed mutagenesis of two residues in
the active site of benzoylformate decarboxylase from P. putida
reportedly altered the affinity (K.sub.m) towards natural and
non-natural substrates (Siegert et al., Protein Eng Des Sel
18:345-357 (2005)). Cytochrome c peroxidase (CCP) from
Saccharomyces cerevisiae was subjected to directed molecular
evolution to generate mutants with increased activity against the
classical peroxidase substrate guaiacol, thus changing the
substrate specificity of CCP from the protein cytochrome c to a
small organic molecule. After three rounds of DNA shuffling and
screening, mutants were isolated which possessed a 300-fold
increased activity against guaiacol and up to 1000-fold increased
specificity for this substrate relative to that for the natural
substrate (Iffland et al., Biochemistry 39:10790-10798 (2000)).
[0181] In some cases, enzymes with different substrate preferences
than either of the parent enzymes have been obtained. For example,
biphenyl-dioxygenase-mediated degradation of polychlorinated
biphenyls was improved by shuffling genes from two bacteria,
Pseudomonas pseudoalcaligens and Burkholderia cepacia (Kumamaru et
al., Nat. Biotechnol. 16:663-666 (1998)). The resulting chimeric
biphenyl oxygenases showed different substrate preferences than
both the parental enzymes and enhanced the degradation activity
towards related biphenyl compounds and single aromatic ring
hydrocarbons such as toluene and benzene which were originally poor
substrates for the enzyme.
[0182] In addition to changing enzyme specificity, it is also
possible to enhance the activities on substrates for which the
enzymes naturally have low activities. One study demonstrated that
amino acid racemase from P. putida that had broad substrate
specificity (on lysine, arginine, alanine, serine, methionine,
cysteine, leucine and histidine among others) but low activity
towards tryptophan could be improved significantly by random
mutagenesis (Kino et al., Appl. Microbiol. Biotechnol. 73:1299-1305
(2007)). Similarly, the active site of the bovine BCKAD was
engineered to favor alternate substrate acetyl-CoA (Meng and
Chuang, Biochemistry 33:12879-12885 (1994)). An interesting aspect
of these approaches is that even if random methods have been
applied to generate these mutated enzymes with efficacious
activities, the exact mutations or structural changes that confer
the improvement in activity can be identified. For example, in the
aforementioned study, the mutations that facilitated improved
activity on tryptophan was traced back to two different
positions.
[0183] Directed evolution has also been used to express proteins
that are difficult to express. For example, by subjecting
horseradish peroxidase to random mutagenesis and gene
recombination, mutants were identified that had more than 14-fold
higher activity than the wild type (Lin et al., Biotechnol. Prog.
15:467-471 (1999)).
[0184] Another example of directed evolution shows the extensive
modifications to which an enzyme can be subjected to achieve a
range of desired functions. The enzyme lactate dehydrogenase from
Bacillus stearothermophilus was subjected to site-directed
mutagenesis, and three amino acid substitutions were made at sites
that were believed to determine the specificity towards different
hydroxyacids (Clarke et al., Biochem. Biophys. Res. Commun.
148:15-23 (1987)). After these mutations, the specificity for
oxaloacetate over pyruvate was increased to 500 in contrast to the
wild type enzyme that had a catalytic specificity for pyruvate over
oxaloacetate of 1000. This enzyme was further engineered using
site-directed mutagenesis to have activity towards branched-chain
substituted pyruvates (Wilks et al., Biochemistry 29:8587-8591
(1990)). Specifically, the enzyme had a 55-fold improvement in
K.sub.cat for alpha-ketoisocaproate. Three structural modifications
were made in the same enzyme to change its substrate specificity
from lactate to malate. The enzyme was highly active and specific
towards malate (Wilks et al., Science 242:1541-1544 (1988)). The
same enzyme from B. stearothermophilus was subsequently engineered
to have high catalytic activity towards alpha-keto acids with
positively charged side chains, such as those containing ammonium
groups (Hogan et al., Biochemistry 34:4225-4230 (1995)). Mutants
with acidic amino acids introduced at position 102 of the enzyme
favored binding of such side chain ammonium groups. The results
obtained proved that the mutants showed up to 25-fold improvements
in k.sub.cat/K.sub.m values for omega-amino-alpha-keto acid
substrates. Interestingly, this enzyme was also structurally
modified to function as a phenyllactate dehydrogenase instead of a
lactate dehydrogenase (Wilks et al., Biochemistry 31:7802-7806
1992). Restriction sites were introduced into the gene for the
enzyme which allowed a region of the gene to be excised. This
region coded for a mobile surface loop of the polypeptide (residues
98-110) which normally seals the active site from bulk solvent and
is a major determinant of substrate specificity. The variable
length and sequence loops were inserted so that hydroxyacid
dehydrogenases with altered substrate specificities were generated.
With one longer loop construction, activity with pyruvate was
reduced one-million-fold but activity with phenylpyruvate was
largely unaltered. A switch in specificity (k.sub.cat/K.sub.m) of
390,000-fold was achieved. The 1700:1 selectivity of this enzyme
for phenylpyruvate over pyruvate is that required in a
phenyllactate dehydrogenase. The studies described above indicate
that various approaches of enzyme engineering can be used to obtain
enzymes for the BDO pathways as disclosed herein.
[0185] As disclosed herein, biosynthetic pathways to 1,4-butanediol
from a number of central metabolic intermediates are can be
utilized, including acetyl-CoA, succinyl-CoA, alpha-ketoglutarate,
glutamate, 4-aminobutyrate, and homoserine. Acetyl-CoA,
succinyl-CoA and alpha-ketoglutarate are common intermediates of
the tricarboxylic acid (TCA) cycle, a series of reactions that is
present in its entirety in nearly all living cells that utilize
oxygen for cellular respiration and is present in truncated forms
in a number of anaerobic organisms. Glutamate is an amino acid that
is derived from alpha-ketoglutarate via glutamate dehydrogenase or
any of a number of transamination reactions (see FIG. 8B).
4-aminobutyrate can be formed by the decarboxylation of glutamate
(see FIG. 8B) or from acetoacetyl-CoA via the pathway disclosed in
FIG. 9C. Acetoacetyl-CoA is derived from the condensation of two
acetyl-CoA molecules by way of the enzyme, acetyl-coenzyme A
acetyltransferase, or equivalently, acetoacetyl-coenzyme A
thiolase. Homoserine is an intermediate in threonine and methionine
metabolism, formed from oxaloacetate via aspartate. The conversion
of oxaloacetate to homoserine requires one NADH, two NADPH, and one
ATP.
[0186] Pathways other than those exemplified above also can be
employed to generate the biosynthesis of BDO in non-naturally
occurring microbial organisms. In one embodiment, biosynthesis can
be achieved using a L-homoserine to BDO pathway (see FIG. 13). This
pathway has a molar yield of 0.90 mol/mol glucose, which appears
restricted by the availability of reducing equivalents. A second
pathway synthesizes BDO from acetoacetyl-CoA and is capable of
achieving the maximum theoretical yield of 1.091 mol/mol glucose
(see FIG. 9). Implementation of either pathway can be achieved by
introduction of two exogenous enzymes into a host organism such as
E. coli, and both pathways can additionally complement BDO
production via succinyl-CoA. Pathway enzymes, thermodynamics,
theoretical yields and overall feasibility are described further
below.
[0187] A homoserine pathway also can be engineered to generate
BDO-producing microbial organisms. Homoserine is an intermediate in
threonine and methionine metabolism, formed from oxaloacetate via
aspartate. The conversion of oxaloacetate to homoserine requires
one NADH, two NADPH, and one ATP (FIG. 2). Once formed, homoserine
feeds into biosynthetic pathways for both threonine and methionine.
In most organisms, high levels of threonine or methionine feedback
to repress the homoserine biosynthesis pathway (Caspi et al.,
Nucleic Acids Res. 34:D511-D516 (1990)).
[0188] The transformation of homoserine to 4-hydroxybutyrate (4-HB)
can be accomplished in two enzymatic steps as described herein. The
first step of this pathway is deamination of homoserine by a
putative ammonia lyase. In step 2, the product alkene,
4-hydroxybut-2-enoate is reduced to 4-HB by a putative reductase at
the cost of one NADH. 4-HB can then be converted to BDO.
[0189] Enzymes available for catalyzing the above transformations
are disclosed herein. For example, the ammonia lyase in step 1 of
the pathway closely resembles the chemistry of aspartate
ammonia-lyase (aspartase). Aspartase is a widespread enzyme in
microorganisms, and has been characterized extensively (Viola, R.
E., Mol. Biol. 74:295-341 (2008)). The crystal structure of the E.
coli aspartase has been solved (Shi et al., Biochemistry
36:9136-9144 (1997)), so it is therefore possible to directly
engineer mutations in the enzyme's active site that would alter its
substrate specificity to include homoserine. The oxidoreductase in
step 2 has chemistry similar to several well-characterized enzymes
including fumarate reductase in the E. coli TCA cycle. Since the
thermodynamics of this reaction are highly favorable, an endogenous
reductase with broad substrate specificity will likely be able to
reduce 4-hydroxybut-2-enoate. The yield of this pathway under
anaerobic conditions is 0.9 mol BDO per mol glucose.
[0190] The succinyl-CoA pathway was found to have a higher yield
due to the fact that it is more energetically efficient. The
conversion of one oxaloacetate molecule to BDO via the homoserine
pathway will require the expenditure of 2 ATP equivalents. Because
the conversion of glucose to two oxaloacetate molecules can
generate a maximum of 3 ATP molecules assuming PEP carboxykinase to
be reversible, the overall conversion of glucose to BDO via
homoserine has a negative energetic yield. As expected, if it is
assumed that energy can be generated via respiration, the maximum
yield of the homoserine pathway increases to 1.05 mol/mol glucose
which is 96% of the succinyl-CoA pathway yield. The succinyl-CoA
pathway can channel some of the carbon flux through pyruvate
dehydrogenase and the oxidative branch of the TCA cycle to generate
both reducing equivalents and succinyl-CoA without an energetic
expenditure. Thus, it does not encounter the same energetic
difficulties as the homoserine pathway because not all of the flux
is channeled through oxaloacetate to succinyl-CoA to BDO. Overall,
the homoserine pathway demonstrates a high-yielding route to
BDO.
[0191] An acetoacetate pathway also can be engineered to generate
BDO-producing microbial organisms. Acetoacetate can be formed from
acetyl-CoA by enzymes involved in fatty acid metabolism, including
acetyl-CoA acetyltransferase and acetoacetyl-CoA transferase.
Biosynthetic routes through acetoacetate are also particularly
useful in microbial organisms that can metabolize single carbon
compounds such as carbon monoxide, carbon dioxide or methanol to
form acetyl-CoA.
[0192] A three step route from acetoacetyl-CoA to 4-aminobutyrate
(see FIG. 9C) can be used to synthesize BDO through
acetoacetyl-CoA. 4-Aminobutyrate can be converted to succinic
semialdehyde as shown in FIG. 8B. Succinic semialdehyde, which is
one reduction step removed from succinyl-CoA or one decarboxylation
step removed from .alpha.-ketoglutarate, can be converted to BDO
following three reductions steps (FIG. 1). Briefly, step 1 of this
pathway involves the conversion of acetoacetyl-CoA to acetoacetate
by, for example, the E. coli acetoacetyl-CoA transferase encoded by
the atoA and atoD genes (Hanai et al., Appl. Environ. Microbiol.
73: 7814-7818 (2007)). Step 2 of the acetoacetyl-CoA biopathway
entails conversion of acetoacetate to 3-aminobutanoate by an
.omega.-aminotransferase. The .omega.-amino acid:pyruvate
aminotransferase (.omega.-APT) from Alcaligens denitrificans was
overexpressed in E. coli and shown to have a high activity toward
3-aminobutanoate in vitro (Yun et al., Appl. Environ. Microbiol.
70:2529-2534 (2004)).
[0193] In step 2, a putative aminomutase shifts the amine group
from the 3- to the 4-position of the carbon backbone. An
aminomutase performing this function on 3-aminobutanoate has not
been characterized, but an enzyme from Clostridium sticklandii has
a very similar mechanism. The enzyme, D-lysine-5,6-aminomutase, is
involved in lysine biosynthesis.
[0194] The synthetic route to BDO from acetoacetyl-CoA passes
through 4-aminobutanoate, a metabolite in E. coli that is normally
formed from decarboxylation of glutamate. Once formed,
4-aminobutanoate can be converted to succinic semialdehyde by
4-aminobutanoate transaminase (2.6.1.19), an enzyme which has been
biochemically characterized.
[0195] One consideration for selecting candidate enzymes in this
pathway is the stereoselectivity of the enzymes involved in steps 2
and 3. The .omega.-ABT in Alcaligens denitrificans is specific to
the L-stereoisomer of 3-aminobutanoate, while
D-lysine-5,6-aminomutase likely requires the D-stereoisomer. If
enzymes with complementary stereoselectivity are not initially
found or engineered, a third enzyme can be added to the pathway
with racemase activity that can convert L-3-aminobutanoate to
D-3-aminobutanoate. While amino acid racemases are widespread,
whether these enzymes can function on .omega.-amino acids is not
known.
[0196] The maximum theoretical molar yield of this pathway under
anaerobic conditions is 1.091 mol/mol glucose. In order to generate
flux from acetoacetyl-CoA to BDO it was necessary to assume that
acetyl-CoA:acetoacetyl-CoA transferase is reversible. The function
of this enzyme in E. coli is to metabolize short-chain fatty acids
by first converting them into thioesters.
[0197] While the operation of acetyl-CoA:acetoacetyl-CoA
transferase in the acetate-consuming direction has not been
demonstrated experimentally in E. coli, studies on similar enzymes
in other organisms support the assumption that this reaction is
reversible. The enzyme butyryl-CoA:acetate:CoA transferase in gut
microbes Roseburia sp. and F. prasnitzii operates in the acetate
utilizing direction to produce butyrate (Duncan et al., Appl.
Environ. Microbiol 68:5186-5190 (2002)). Another very similar
enzyme, acetyl: succinate CoA-transferase in Trypanosoma brucei,
also operates in the acetate utilizing direction. This reaction has
a .DELTA..sub.rxnG close to equilibrium, so high concentrations of
acetate can likely drive the reaction in the direction of interest.
At the maximum theoretical BDO production rate of 1.09 mol/mol
glucose simulations predict that E. coli can generate 1.098 mol ATP
per mol glucose with no fermentation byproducts. This ATP yield
should be sufficient for cell growth, maintenance, and production.
The acetoacetatyl-CoA biopathway is a high-yielding route to BDO
from acetyl-CoA.
[0198] Therefore, in addition to any of the various modifications
exemplified previously for establishing 4-HB biosynthesis in a
selected host, the BDO producing microbial organisms can include
any of the previous combinations and permutations of 4-HB pathway
metabolic modifications as well as any combination of expression
for CoA-independent aldehyde dehydrogenase, CoA-dependent aldehyde
dehydrogenase or an alcohol dehydrogenase or other enzymes
disclosed herein to generate biosynthetic pathways for GBL and/or
BDO. Therefore, the BDO producers of the invention can have
exogenous expression of, for example, one, two, three, four, five,
six, seven, eight, nine, or up to all enzymes corresponding to any
of the 4-HB pathway and/or any of the BDO pathway enzymes disclosed
herein.
[0199] Design and construction of the genetically modified
microbial organisms is carried out using methods well known in the
art to achieve sufficient amounts of expression to produce BDO. In
particular, the non-naturally occurring microbial organisms of the
invention can achieve biosynthesis of BDO resulting in
intracellular concentrations between about 0.1-200 mM or more, such
as about 0.1-25 mM or more, as discussed above. For example, the
intracellular concentration of BDO is between about 3-20 mM,
particularly between about 5-15 mM and more particularly between
about 8-12 mM, including about 10 mM or more. Intracellular
concentrations between and above each of these exemplary ranges
also can be achieved from the non-naturally occurring microbial
organisms of the invention. As with the 4-HB producers, the BDO
producers also can be sustained, cultured or fermented under
anaerobic conditions.
[0200] The invention further provides a method for the production
of 4-HB. The method includes culturing a non-naturally occurring
microbial organism having a 4-hydroxybutanoic acid (4-HB)
biosynthetic pathway comprising at least one exogenous nucleic acid
encoding 4-hydroxybutanoate dehydrogenase, CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, glutamate:succinic
semialdehyde transaminase, .alpha.-ketoglutarate decarboxylase, or
glutamate decarboxylase under substantially anaerobic conditions
for a sufficient period of time to produce monomeric
4-hydroxybutanoic acid (4-HB). The method can additionally include
chemical conversion of 4-HB to GBL and to BDO or THF, for
example.
[0201] Additionally provided is a method for the production of
4-HB. The method includes culturing a non-naturally occurring
microbial organism having a 4-hydroxybutanoic acid (4-HB)
biosynthetic pathway including at least one exogenous nucleic acid
encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase,
CoA-dependent succinic semialdehyde dehydrogenase or
.alpha.-ketoglutarate decarboxylase under substantially anaerobic
conditions for a sufficient period of time to produce monomeric
4-hydroxybutanoic acid (4-HB). The 4-HB product can be secreted
into the culture medium.
[0202] Further provided is a method for the production of BDO. The
method includes culturing a non-naturally occurring microbial
biocatalyst or microbial organism, comprising a microbial organism
having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO)
biosynthetic pathways, the pathways including at least one
exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase,
succinyl-CoA synthetase, CoA-dependent succinic semialdehyde
dehydrogenase, 4-hydroxybutyrate:CoA transferase, 4-hydroxybutyrate
kinase, phosphotranshydroxybutyrylase, .alpha.-ketoglutarate
decarboxylase, aldehyde dehydrogenase, alcohol dehydrogenase or an
aldehyde/alcohol dehydrogenase for a sufficient period of time to
produce 1,4-butanediol (BDO). The BDO product can be secreted into
the culture medium.
[0203] Additionally provided are methods for producing BDO by
culturing a non-naturally occurring microbial organism having a BDO
pathway of the invention. The BDO pathway can comprise at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA
hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA
oxidoreductase (deaminating), 4-aminobutyryl-CoA transaminase, or
4-hydroxybutyryl-CoA dehydrogenase (see Example VII and Table
17).
[0204] Alternatively, the BDO pathway can compare at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA
hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA reductase
(alcohol forming), 4-aminobutyryl-CoA reductase, 4-aminobutan-1-ol
dehydrogenase, 4-aminobutan-1-ol oxidoreductase (deaminating) or
4-aminobutan-1-ol transaminase (see Example VII and Table 18).
[0205] In addition, the invention provides a method for producing
BDO, comprising culturing a non-naturally occurring microbial
organism having a BDO pathway, the pathway comprising at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising 4-aminobutyrate kinase, 4-aminobutyraldehyde
dehydrogenase (phosphorylating), 4-aminobutan-1-ol dehydrogenase,
4-aminobutan-1-ol oxidoreductase (deaminating), 4-aminobutan-1-ol
transaminase, [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase
(deaminating), [(4-aminobutanolyl)oxy]phosphonic acid transaminase,
4-hydroxybutyryl-phosphate dehydrogenase, or 4-hydroxybutyraldehyde
dehydrogenase (phosphorylating) (see Example VII and Table 19).
[0206] The invention further provides a method for producing BDO,
comprising culturing a non-naturally occurring microbial organism
having a BDO pathway, the pathway comprising at least one exogenous
nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising alpha-ketoglutarate 5-kinase, 2,5-dioxopentanoic
semialdehyde dehydrogenase (phosphorylating), 2,5-dioxopentanoic
acid reductase, alpha-ketoglutarate CoA transferase,
alpha-ketoglutaryl-CoA hydrolase, alpha-ketoglutaryl-CoA ligase,
alpha-ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid
dehydrogenase, alpha-ketoglutaryl-CoA reductase (alcohol forming),
5-hydroxy-2-oxopentanoic acid decarboxylase, or
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation)(see
Example VIII and Table 20).
[0207] The invention additionally provides a method for producing
BDO, comprising culturing a non-naturally occurring microbial
organism having a BDO pathway, the pathway comprising at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising glutamate CoA transferase, glutamyl-CoA hydrolase,
glutamyl-CoA ligase, glutamate 5-kinase, glutamate-5-semialdehyde
dehydrogenase (phosphorylating), glutamyl-CoA reductase,
glutamate-5-semialdehyde reductase, glutamyl-CoA reductase (alcohol
forming), 2-amino-5-hydroxypentanoic acid oxidoreductase
(deaminating), 2-amino-5-hydroxypentanoic acid transaminase,
5-hydroxy-2-oxopentanoic acid decarboxylase,
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation)(see
Example IX and Table 21).
[0208] The invention additionally includes a method for producing
BDO, comprising culturing a non-naturally occurring microbial
organism having a BDO pathway, the pathway comprising at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising 3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxybutyryl-CoA
dehydratase, vinylacetyl-CoA .DELTA.-isomerase, or
4-hydroxybutyryl-CoA dehydratase (see Example X and Table 22).
[0209] Also provided is a method for producing BDO, comprising
culturing a non-naturally occurring microbial organism having a BDO
pathway, the pathway comprising at least one exogenous nucleic acid
encoding a BDO pathway enzyme expressed in a sufficient amount to
produce BDO, under conditions and for a sufficient period of time
to produce BDO, the BDO pathway comprising homoserine deaminase,
homoserine CoA transferase, homoserine-CoA hydrolase,
homoserine-CoA ligase, homoserine-CoA deaminase,
4-hydroxybut-2-enoyl-CoA transferase, 4-hydroxybut-2-enoyl-CoA
hydrolase, 4-hydroxybut-2-enoyl-CoA ligase, 4-hydroxybut-2-enoate
reductase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA
hydrolase, 4-hydroxybutyryl-CoA ligase, or 4-hydroxybut-2-enoyl-CoA
reductase (see Example XI and Table 23).
[0210] The invention additionally provides a method for producing
BDO, comprising culturing a non-naturally occurring microbial
organism having a BDO pathway, the pathway comprising at least one
exogenous nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO, under conditions and for a
sufficient period of time to produce BDO, the BDO pathway
comprising succinyl-CoA reductase (alcohol forming),
4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase,
4-hydroxybutanal dehydrogenase (phosphorylating). Such a BDO
pathway can further comprise succinyl-CoA reductase,
4-hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase,
4-hydroxybutyrate kinase, phosphotrans-4-hydroxybutyrylase,
4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase
(alcohol forming), or 1,4-butanediol dehydrogenase.
[0211] Also provided is a method for producing BDO, comprising
culturing a non-naturally occurring microbial organism having a BDO
pathway, the pathway comprising at least one exogenous nucleic acid
encoding a BDO pathway enzyme expressed in a sufficient amount to
produce BDO, under conditions and for a sufficient period of time
to produce BDO, the BDO pathway comprising glutamate dehydrogenase,
4-aminobutyrate oxidoreductase (deaminating), 4-aminobutyrate
transaminase, glutamate decarboxylase, 4-hydroxybutyryl-CoA
hydrolase, 4-hydroxybutyryl-CoA ligase, 4-hydroxybutanal
dehydrogenase (phosphorylating).
[0212] The invention additionally provides methods of producing a
desired product using the genetically modified organisms disclosed
herein that allow improved production of a desired product such as
BDO by increasing the product or decreasing undesirable byproducts.
Thus, the invention provides a method for producing 1,4-butanediol
(BDO), comprising culturing the non-naturally occurring microbial
organisms disclosed herein under conditions and for a sufficient
period of time to produce BDO. In one embodiment, the invention
provides a method of producing BDO using a non-naturally occurring
microbial organism, comprising a microbial organism having a
1,4-butanediol (BDO) pathway comprising at least one exogenous
nucleic acid encoding a BDO pathway enzyme expressed in a
sufficient amount to produce BDO. In one embodiment, the microbial
organism is genetically modified to express exogenous succinyl-CoA
synthetase (see Example XII). For example, the succinyl-CoA
synthetase can be encoded by an Escherichia coli sucCD genes.
[0213] In another embodiment, the microbial organism is genetically
modified to express exogenous alpha-ketoglutarate decarboxylase
(see Example XIII) For example, the alpha-ketoglutarate
decarboxylase can be encoded by the Mycobacterium bovis sucA gene.
In still another embodiment, the microbial organism is genetically
modified to express exogenous succinate semialdehyde dehydrogenase
and 4-hydroxybutyrate dehydrogenase and optionally
4-hydroxybutyryl-CoA/acetyl-CoA transferase (see Example XIII) For
example, the succinate semialdehyde dehydrogenase (CoA-dependent),
4-hydroxybutyrate dehydrogenase and 4-hydroxybutyryl-CoA/acetyl-CoA
transferase can be encoded by Porphyromonas gingivalis W83 genes.
In an additional embodiment, the microbial organism is genetically
modified to express exogenous butyrate kinase and
phosphotransbutyrylase (see Example XIII) For example, the butyrate
kinase and phosphotransbutyrylase can be encoded by Clostridium
acetobutilicum buk1 and ptb genes.
[0214] In yet another embodiment, the microbial organism is
genetically modified to express exogenous 4-hydroxybutyryl-CoA
reductase (see Example XIII) For example, the 4-hydroxybutyryl-CoA
reductase can be encoded by Clostridium beijerinckii ald gene.
Additionally, in an embodiment of the invention, the microbial
organism is genetically modified to express exogenous
4-hydroxybutanal reductase (see Example XIII) For example, the
4-hydroxybutanal reductase can be encoded by Geobacillus
thermoglucosidasius adh1 gene. In another embodiment, the microbial
organism is genetically modified to express exogenous pyruvate
dehydrogenase subunits (see Example XIV). For example, the
exogenous pyruvate dehydrogenase can be NADH insensitive. The
pyruvate dehydrogenase subunit can be encoded by the Klebsiella
pneumonia lpdA gene. In a particular embodiment, the pyruvate
dehydrogenase subunit genes of the microbial organism can be under
the control of a pyruvate formate lyase promoter.
[0215] In still another embodiment, the microbial organism is
genetically modified to disrupt a gene encoding an aerobic
respiratory control regulatory system (see Example XV). For
example, the disruption can be of the arcA gene. Such an organism
can further comprise disruption of a gene encoding malate
dehydrogenase. In a further embodiment, the microbial organism is
genetically modified to express an exogenous NADH insensitive
citrate synthase (see Example XV). For example, the NADH
insensitive citrate synthase can be encoded by gltA, such as an
R163L mutant of gltA. In still another embodiment, the microbial
organism is genetically modified to express exogenous
phosphoenolpyruvate carboxykinase (see Example XVI). For example,
the phosphoenolpyruvate carboxykinase can be encoded by an
Haemophilus influenza phosphoenolpyruvate carboxykinase gene. It is
understood that strains exemplified herein for improved production
of BDO can similarly be used, with appropriate modifications, to
produce other desired products, for example, 4-hydroxybutyrate or
other desired products disclosed herein.
[0216] The invention additionally provides a method for producing
4-hydroxybutanal by culturing a non-naturally occurring microbial
organism, comprising a 4-hydroxybutanal pathway comprising at least
one exogenous nucleic acid encoding a 4-hydroxybutanal pathway
enzyme expressed in a sufficient amount to produce
4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
succinyl-CoA reductase (aldehyde forming); 4-hydroxybutyrate
dehydrogenase; and 4-hydroxybutyrate reductase (see FIG. 58, steps
A-C-D). The invention also provides a method for producing
4-hydroxybutanal by culturing a non-naturally occurring microbial
organism, comprising a 4-hydroxybutanal pathway comprising at least
one exogenous nucleic acid encoding a 4-hydroxybutanal pathway
enzyme expressed in a sufficient amount to produce
4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
alpha-ketoglutarate decarboxylase; 4-hydroxybutyrate dehydrogenase;
and 4-hydroxybutyrate reductase (FIG. 58, steps B-C-D).
[0217] The invention further provides a method for producing
4-hydroxybutanal by culturing a non-naturally occurring microbial
organism, comprising a 4-hydroxybutanal pathway comprising at least
one exogenous nucleic acid encoding a 4-hydroxybutanal pathway
enzyme expressed in a sufficient amount to produce
4-hydroxybutanal, the 4-hydroxybutanal pathway comprising succinate
reductase; 4-hydroxybutyrate dehydrogenase, and 4-hydroxybutyrate
reductase (see FIG. 62, steps F-C-D). In yet another embodiment,
the invention provides a method for producing 4-hydroxybutanal by
culturing a non-naturally occurring microbial organism, comprising
a 4-hydroxybutanal pathway comprising at least one exogenous
nucleic acid encoding a 4-hydroxybutanal pathway enzyme expressed
in a sufficient amount to produce 4-hydroxybutanal, the
4-hydroxybutanal pathway comprising alpha-ketoglutarate
decarboxylase, or glutamate dehydrogenase or glutamate transaminase
and glutamate decarboxylase and 4-aminobutyrate dehydrogenase or
4-aminobutyrate transaminase; 4-hydroxybutyrate dehydrogenase; and
4-hydroxybutyrate reductase (see FIG. 62, steps B or ((J or K)-L-(M
or N))-C-D).
[0218] The invention also provides a method for producing
4-hydroxybutanal by culturing a non-naturally occurring microbial
organism, comprising a 4-hydroxybutanal pathway comprising at least
one exogenous nucleic acid encoding a 4-hydroxybutanal pathway
enzyme expressed in a sufficient amount to produce
4-hydroxybutanal, the 4-hydroxybutanal pathway comprising
alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate
dehydrogenase; and 5-hydroxy-2-oxopentanoate decarboxylase (see
FIG. 62, steps X-Y-Z). The invention further provides a method for
producing 4-hydroxybutyryl-CoA by culturing a non-naturally
occurring microbial organism, comprising a 4-hydroxybutyryl-CoA
pathway comprising at least one exogenous nucleic acid encoding a
4-hydroxybutyryl-CoA pathway enzyme expressed in a sufficient
amount to produce 4-hydroxybutyryl-CoA, the 4-hydroxybutyryl-CoA
pathway comprising alpha-ketoglutarate reductase;
5-hydroxy-2-oxopentanoate dehydrogenase; and
5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation) (see FIG.
62, steps X-Y-AA).
[0219] The invention additionally provides a method for producing
putrescine by culturing a non-naturally occurring microbial
organism, comprising a putrescine pathway comprising at least one
exogenous nucleic acid encoding a putrescine pathway enzyme
expressed in a sufficient amount to produce putrescine, the
putrescine pathway comprising succinate reductase; 4-aminobutyrate
dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate
reductase; and putrescine dehydrogenase or putrescine transaminase
(see FIG. 63, steps F-M/N-C-D/E). In still another embodiment, the
invention provides a method for producing putrescine by culturing a
non-naturally occurring microbial organism, comprising a putrescine
pathway comprising at least one exogenous nucleic acid encoding a
putrescine pathway enzyme expressed in a sufficient amount to
produce putrescine, the putrescine pathway comprising
alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or
4-aminobutyrate transaminase; 4-aminobutyrate reductase; and
putrescine dehydrogenase or putrescine transaminase (see FIG. 63,
steps B-M/N-C-D/E). The invention additionally provides a method
for producing putrescine by culturing a non-naturally occurring
microbial organism, comprising a putrescine pathway comprising at
least one exogenous nucleic acid encoding a putrescine pathway
enzyme expressed in a sufficient amount to produce putrescine, the
putrescine pathway comprising glutamate dehydrogenase or glutamate
transaminase; glutamate decarboxylase; 4-aminobutyrate reductase;
and putrescine dehydrogenase or putrescine transaminase (see FIG.
63, steps J/K-L-C-D/E).
[0220] The invention provides in another embodiment a method for
producing putrescine by culturing a non-naturally occurring
microbial organism, comprising a putrescine pathway comprising at
least one exogenous nucleic acid encoding a putrescine pathway
enzyme expressed in a sufficient amount to produce putrescine, the
putrescine pathway comprising alpha-ketoglutarate reductase;
5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate
transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine
dehydrogenase or putrescine transaminase (see FIG. 63, steps
O-P/Q-R-D/E). Also provided is a method for producing putrescine by
culturing a non-naturally occurring microbial organism, comprising
a putrescine pathway comprising at least one exogenous nucleic acid
encoding a putrescine pathway enzyme expressed in a sufficient
amount to produce putrescine, the putrescine pathway comprising
alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate
dehydrogenase or 5-amino-2-oxopentanoate transaminase; ornithine
dehydrogenase or ornithine transaminase; and ornithine
decarboxylase (see FIG. 63, steps O-P/Q-S/T-U). It is understood
that a microbial organism comprising any of the pathways disclosed
herein can be used to produce a desired product or intermediate,
including 4-HB, 4-HBal, BDO or putrescine.
[0221] It is understood that, in methods of the invention, any of
the one or more exogenous nucleic acids can be introduced into a
microbial organism to produce a non-naturally occurring microbial
organism of the invention. The nucleic acids can be introduced so
as to confer, for example, a 4-HB, BDO, THF or GBL biosynthetic
pathway onto the microbial organism. Alternatively, encoding
nucleic acids can be introduced to produce an intermediate
microbial organism having the biosynthetic capability to catalyze
some of the required reactions to confer 4-HB, BDO, THF or GBL
biosynthetic capability. For example, a non-naturally occurring
microbial organism having a 4-HB biosynthetic pathway can comprise
at least two exogenous nucleic acids encoding desired enzymes, such
as the combination of 4-hydroxybutanoate dehydrogenase and
.alpha.-ketoglutarate decarboxylase; 4-hydroxybutanoate
dehydrogenase and CoA-independent succinic semialdehyde
dehydrogenase; 4-hydroxybutanoate dehydrogenase and CoA-dependent
succinic semialdehyde dehydrogenase; CoA-dependent succinic
semialdehyde dehydrogenase and succinyl-CoA synthetase;
succinyl-CoA synthetase and glutamate decarboxylase, and the like.
Thus, it is understood that any combination of two or more enzymes
of a biosynthetic pathway can be included in a non-naturally
occurring microbial organism of the invention. Similarly, it is
understood that any combination of three or more enzymes of a
biosynthetic pathway can be included in a non-naturally occurring
microbial organism of the invention, for example,
4-hydroxybutanoate dehydrogenase, .alpha.-ketoglutarate
decarboxylase and CoA-dependent succinic semialdehyde
dehydrogenase; CoA-independent succinic semialdehyde dehydrogenase
and succinyl-CoA synthetase; 4-hydroxybutanoate dehydrogenase,
CoA-dependent succinic semialdehyde dehydrogenase and
glutamate:succinic semialdehyde transaminase, and so forth, as
desired, so long as the combination of enzymes of the desired
biosynthetic pathway results in production of the corresponding
desired product.
[0222] Similarly, for example, with respect to any one or more
exogenous nucleic acids introduced to confer BDO production, a
non-naturally occurring microbial organism having a BDO
biosynthetic pathway can comprise at least two exogenous nucleic
acids encoding desired enzymes, such as the combination of
4-hydroxybutanoate dehydrogenase and .alpha.-ketoglutarate
decarboxylase; 4-hydroxybutanoate dehydrogenase and
4-hydroxybutyryl CoA:acetyl-CoA transferase; 4-hydroxybutanoate
dehydrogenase and butyrate kinase; 4-hydroxybutanoate dehydrogenase
and phosphotransbutyrylase; 4-hydroxybutyryl CoA:acetyl-CoA
transferase and aldehyde dehydrogenase; 4-hydroxybutyryl
CoA:acetyl-CoA transferase and alcohol dehydrogenase;
4-hydroxybutyryl CoA:acetyl-CoA transferase and an aldehyde/alcohol
dehydrogenase, 4-aminobutyrate-CoA transferase and
4-aminobutyryl-CoA transaminase; 4-aminobutyrate kinase and
4-aminobutan-1-ol oxidoreductase (deaminating), and the like. Thus,
it is understood that any combination of two or more enzymes of a
biosynthetic pathway can be included in a non-naturally occurring
microbial organism of the invention. Similarly, it is understood
that any combination of three or more enzymes of a biosynthetic
pathway can be included in a non-naturally occurring microbial
organism of the invention, for example, 4-hydroxybutanoate
dehydrogenase, .alpha.-ketoglutarate decarboxylase and
4-hydroxybutyryl CoA:acetyl-CoA transferase; 4-hydroxybutanoate
dehydrogenase, butyrate kinase and phosphotransbutyrylase;
4-hydroxybutanoate dehydrogenase, 4-hydroxybutyryl CoA:acetyl-CoA
transferase and aldehyde dehydrogenase; 4-hydroxybutyryl
CoA:acetyl-CoA transferase, aldehyde dehydrogenase and alcohol
dehydrogenase; butyrate kinase, phosphotransbutyrylase and an
aldehyde/alcohol dehydrogenase; 4-aminobutyryl-CoA hydrolase,
4-aminobutyryl-CoA reductase and 4-amino butan-1-ol transaminase;
3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxybutyryl-CoA
dehydratase and 4-hydroxybutyryl-CoA dehydratase, and the like.
Similarly, any combination of four, five or more enzymes of a
biosynthetic pathway as disclosed herein can be included in a
non-naturally occurring microbial organism of the invention, as
desired, so long as the combination of enzymes of the desired
biosynthetic pathway results in production of the corresponding
desired product.
[0223] Any of the non-naturally occurring microbial organisms
described herein can be cultured to produce and/or secrete the
biosynthetic products of the invention. For example, the 4-HB
producers can be cultured for the biosynthetic production of 4-HB.
The 4-HB can be isolated or be treated as described below to
generate GBL, THF and/or BDO. Similarly, the BDO producers can be
cultured for the biosynthetic production of BDO. The BDO can be
isolated or subjected to further treatments for the chemical
synthesis of BDO family compounds, as disclosed herein.
[0224] The growth medium can include, for example, any carbohydrate
source which can supply a source of carbon to the non-naturally
occurring microorganism. Such sources include, for example, sugars
such as glucose, sucrose, xylose, arabinose, galactose, mannose,
fructose and starch. Other sources of carbohydrate include, for
example, renewable feedstocks and biomass. Exemplary types of
biomasses that can be used as feedstocks in the methods of the
invention include cellulosic biomass, hemicellulosic biomass and
lignin feedstocks or portions of feedstocks. Such biomass
feedstocks contain, for example, carbohydrate substrates useful as
carbon sources such as glucose, sucrose, xylose, arabinose,
galactose, mannose, fructose and starch. Given the teachings and
guidance provided herein, those skilled in the art will understand
that renewable feedstocks and biomass other than those exemplified
above also can be used for culturing the microbial organisms of the
invention for the production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine and other compounds of the invention.
[0225] Accordingly, given the teachings and guidance provided
herein, those skilled in the art will understand that a
non-naturally occurring microbial organism can be produced that
secretes the biosynthesized compounds of the invention when grown
on a carbon source such as a carbohydrate. Such compounds include,
for example, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and any of
the intermediates metabolites in the 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathways and/or the combined 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine pathways. All that is required is to engineer in one
or more of the enzyme activities shown in FIG. 1 to achieve
biosynthesis of the desired compound or intermediate including, for
example, inclusion of some or all of the 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine biosynthetic pathways. Accordingly, the invention
provides a non-naturally occurring microbial organism that secretes
4-HB when grown on a carbohydrate, secretes BDO when grown on a
carbohydrate and/or secretes any of the intermediate metabolites
shown in FIG. 1, 8-13, 58, 62 or 63 when grown on a carbohydrate. A
BDO producing microbial organisms of the invention can initiate
synthesis from, for example, succinate, succinyl-CoA,
.alpha.-ketogluterate, succinic semialdehyde, 4-HB,
4-hydroxybutyrylphosphate, 4-hydroxybutyryl-CoA (4-HB-CoA) and/or
4-hydroxybutyraldehyde.
[0226] In some embodiments, culture conditions include anaerobic or
substantially anaerobic growth or maintenance conditions. Exemplary
anaerobic conditions have been described previously and are well
known in the art. Exemplary anaerobic conditions for fermentation
processes are described below in the Examples. Any of these
conditions can be employed with the non-naturally occurring
microbial organisms as well as other anaerobic conditions well
known in the art. Under such anaerobic conditions, the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine producers can synthesize
monomeric 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine, respectively,
at intracellular concentrations of 5-10 mM or more as well as all
other concentrations exemplified previously.
[0227] A number of downstream compounds also can be generated for
the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producing
non-naturally occurring microbial organisms of the invention. With
respect to the 4-HB producing microbial organisms of the invention,
monomeric 4-HB and GBL exist in equilibrium in the culture medium.
The conversion of 4-HB to GBL can be efficiently accomplished by,
for example, culturing the microbial organisms in acid pH medium. A
pH less than or equal to 7.5, in particular at or below pH 5.5,
spontaneously converts 4-HB to GBL.
[0228] The resultant GBL can be separated from 4-HB and other
components in the culture using a variety of methods well known in
the art. Such separation methods include, for example, the
extraction procedures exemplified in the Examples as well as
methods which include continuous liquid-liquid extraction,
pervaporation, membrane filtration, membrane separation, reverse
osmosis, electrodialysis, distillation, crystallization,
centrifugation, extractive filtration, ion exchange chromatography,
size exclusion chromatography, adsorption chromatography, and
ultrafiltration. All of the above methods are well known in the
art. Separated GBL can be further purified by, for example,
distillation.
[0229] Another down stream compound that can be produced from the
4-HB producing non-naturally occurring microbial organisms of the
invention includes, for example, BDO. This compound can be
synthesized by, for example, chemical hydrogenation of GBL.
Chemical hydrogenation reactions are well known in the art. One
exemplary procedure includes the chemical reduction of 4-HB and/or
GBL or a mixture of these two components deriving from the culture
using a heterogeneous or homogeneous hydrogenation catalyst
together with hydrogen, or a hydride-based reducing agent used
stoichiometrically or catalytically, to produce 1,4-butanediol.
[0230] Other procedures well known in the art are equally
applicable for the above chemical reaction and include, for
example, WO No. 82/03854 (Bradley, et al.), which describes the
hydrogenolysis of gamma-butyrolactone in the vapor phase over a
copper oxide and zinc oxide catalyst. British Pat. No. 1,230,276,
which describes the hydrogenation of gamma-butyrolactone using a
copper oxide-chromium oxide catalyst. The hydrogenation is carried
out in the liquid phase. Batch reactions also are exemplified
having high total reactor pressures. Reactant and product partial
pressures in the reactors are well above the respective dew points.
British Pat. No. 1,314,126, which describes the hydrogenation of
gamma-butyrolactone in the liquid phase over a
nickel-cobalt-thorium oxide catalyst. Batch reactions are
exemplified as having high total pressures and component partial
pressures well above respective component dew points. British Pat.
No. 1,344,557, which describes the hydrogenation of
gamma-butyrolactone in the liquid phase over a copper
oxide-chromium oxide catalyst. A vapor phase or vapor-containing
mixed phase is indicated as suitable in some instances. A
continuous flow tubular reactor is exemplified using high total
reactor pressures. British Pat. No. 1,512,751, which describes the
hydrogenation of gamma-butyrolactone to 1,4-butanediol in the
liquid phase over a copper oxide-chromium oxide catalyst. Batch
reactions are exemplified with high total reactor pressures and,
where determinable, reactant and product partial pressures well
above the respective dew points. U.S. Pat. No. 4,301,077, which
describes the hydrogenation to 1,4-butanediol of
gamma-butyrolactone over a Ru--Ni--Co--Zn catalyst. The reaction
can be conducted in the liquid or gas phase or in a mixed
liquid-gas phase. Exemplified are continuous flow liquid phase
reactions at high total reactor pressures and relatively low
reactor productivities. U.S. Pat. No. 4,048,196, which describes
the production of 1,4-butanediol by the liquid phase hydrogenation
of gamma-butyrolactone over a copper oxide-zinc oxide catalyst.
Further exemplified is a continuous flow tubular reactor operating
at high total reactor pressures and high reactant and product
partial pressures. And U.S. Pat. No. 4,652,685, which describes the
hydrogenation of lactones to glycols.
[0231] A further downstream compound that can be produced form the
4-HB producing microbial organisms of the invention includes, for
example, THF. This compound can be synthesized by, for example,
chemical hydrogenation of GBL. One exemplary procedure well known
in the art applicable for the conversion of GBL to THF includes,
for example, chemical reduction of 4-HB and/or GBL or a mixture of
these two components deriving from the culture using a
heterogeneous or homogeneous hydrogenation catalyst together with
hydrogen, or a hydride-based reducing agent used stoichiometrically
or catalytically, to produce tetrahydrofuran. Other procedures well
know in the art are equally applicable for the above chemical
reaction and include, for example, U.S. Pat. No. 6,686,310, which
describes high surface area sol-gel route prepared hydrogenation
catalysts. Processes for the reduction of maleic acid to
tetrahydrofuran (THF) and 1,4-butanediol (BDO) and for the
reduction of gamma butyrolactone to tetrahydrofuran and
1,4-butanediol also are described.
[0232] The culture conditions can include, for example, liquid
culture procedures as well as fermentation and other large scale
culture procedures. As described further below in the Examples,
particularly useful yields of the biosynthetic products of the
invention can be obtained under anaerobic or substantially
anaerobic culture conditions.
[0233] Suitable purification and/or assays to test for the
production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine can be
performed using well known methods. Suitable replicates such as
triplicate cultures can be grown for each engineered strain to be
tested. For example, product and byproduct formation in the
engineered production host can be monitored. The final product and
intermediates, and other organic compounds, can be analyzed by
methods such as HPLC (High Performance Liquid Chromatography),
GC-MS (Gas Chromatography-Mass Spectroscopy) and LC-MS (Liquid
Chromatography-Mass Spectroscopy) or other suitable analytical
methods using routine procedures well known in the art. The release
of product in the fermentation broth can also be tested with the
culture supernatant. Byproducts and residual glucose can be
quantified by HPLC using, for example, a refractive index detector
for glucose and alcohols, and a UV detector for organic acids (Lin
et al., Biotechnol. Bioeng. 90:775-779 (2005)), or other suitable
assay and detection methods well known in the art. The individual
enzyme or protein activities from the exogenous DNA sequences can
also be assayed using methods well known in the art.
[0234] The 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine product can be
separated from other components in the culture using a variety of
methods well known in the art. Such separation methods include, for
example, extraction procedures as well as methods that include
continuous liquid-liquid extraction, pervaporation, membrane
filtration, membrane separation, reverse osmosis, electrodialysis,
distillation, crystallization, centrifugation, extractive
filtration, ion exchange chromatography, size exclusion
chromatography, adsorption chromatography, and ultrafiltration. All
of the above methods are well known in the art.
[0235] The invention further provides a method of manufacturing
4-HB. The method includes fermenting a non-naturally occurring
microbial organism having a 4-hydroxybutanoic acid (4-HB)
biosynthetic pathway comprising at least one exogenous nucleic acid
encoding 4-hydroxybutanoate dehydrogenase, CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, glutamate: succinic
semialdehyde transaminase, .alpha.-ketoglutarate decarboxylase, or
glutamate decarboxylase under substantially anaerobic conditions
for a sufficient period of time to produce monomeric
4-hydroxybutanoic acid (4-HB), the process comprising fed-batch
fermentation and batch separation; fed-batch fermentation and
continuous separation, or continuous fermentation and continuous
separation.
[0236] The culture and chemical hydrogenations described above also
can be scaled up and grown continuously for manufacturing of 4-HB,
4-HBal, 4-HBCoA, GBL, BDO and/or THF or putrescine. Exemplary
growth procedures include, for example, fed-batch fermentation and
batch separation; fed-batch fermentation and continuous separation,
or continuous fermentation and continuous separation. All of these
processes are well known in the art. Employing the 4-HB producers
allows for simultaneous 4-HB biosynthesis and chemical conversion
to GBL, BDO and/or THF by employing the above hydrogenation
procedures simultaneous with continuous cultures methods such as
fermentation. Other hydrogenation procedures also are well known in
the art and can be equally applied to the methods of the
invention.
[0237] Fermentation procedures are particularly useful for the
biosynthetic production of commercial quantities of 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine. Generally, and as with non-continuous
culture procedures, the continuous and/or near-continuous
production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine will include
culturing a non-naturally occurring 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine producing organism of the invention in sufficient
nutrients and medium to sustain and/or nearly sustain growth in an
exponential phase. Continuous culture under such conditions can be
include, for example, 1 day, 2, 3, 4, 5, 6 or 7 days or more.
Additionally, continuous culture can include 1 week, 2, 3, 4 or 5
or more weeks and up to several months. Alternatively, organisms of
the invention can be cultured for hours, if suitable for a
particular application. It is to be understood that the continuous
and/or near-continuous culture conditions also can include all time
intervals in between these exemplary periods. It is further
understood that the time of culturing the microbial organism of the
invention is for a sufficient period of time to produce a
sufficient amount of product for a desired purpose.
[0238] Fermentation procedures are well known in the art. Briefly,
fermentation for the biosynthetic production of 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine or other 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine derived products, including intermediates, of the
invention can be utilized in, for example, fed-batch fermentation
and batch separation; fed-batch fermentation and continuous
separation, or continuous fermentation and continuous separation.
Examples of batch and continuous fermentation procedures well known
in the art are exemplified further below in the Examples.
[0239] In addition, to the above fermentation procedures using the
4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producers of the invention
for continuous production of substantial quantities of 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine, including monomeric 4-HB,
respectively, the 4-HB producers also can be, for example,
simultaneously subjected to chemical synthesis procedures as
described previously for the chemical conversion of monomeric 4-HB
to, for example, GBL, BDO and/or THF. The BDO producers can
similarly be, for example, simultaneously subjected to chemical
synthesis procedures as described previously for the chemical
conversion of BDO to, for example, THF, GBL, pyrrolidones and/or
other BDO family compounds. In addition, the products of the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine producers can be separated from
the fermentation culture and sequentially subjected to chemical
conversion, as disclosed herein.
[0240] Briefly, hydrogenation of GBL in the fermentation broth can
be performed as described by Frost et al., Biotechnology Progress
18: 201-211 (2002). Another procedure for hydrogenation during
fermentation include, for example, the methods described in, for
example, U.S. Pat. No. 5,478,952. This method is further
exemplified in the Examples below.
[0241] Therefore, the invention additionally provides a method of
manufacturing .gamma.-butyrolactone (GBL), tetrahydrofuran (THF) or
1,4-butanediol (BDO). The method includes fermenting a
non-naturally occurring microbial organism having 4-hydroxybutanoic
acid (4-HB) and/or 1,4-butanediol (BDO) biosynthetic pathways, the
pathways comprise at least one exogenous nucleic acid encoding
4-hydroxybutanoate dehydrogenase, CoA-independent succinic
semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent
succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA
transferase, glutamate: succinic semialdehyde transaminase,
.alpha.-ketoglutarate decarboxylase, glutamate decarboxylase,
4-hydroxybutanoate kinase, phosphotransbutyrylase, CoA-independent
1,4-butanediol semialdehyde dehydrogenase, CoA-dependent
1,4-butanediol semialdehyde dehydrogenase, CoA-independent
1,4-butanediol alcohol dehydrogenase or CoA-dependent
1,4-butanediol alcohol dehydrogenase, under substantially anaerobic
conditions for a sufficient period of time to produce
1,4-butanediol (BDO), GBL or THF, the fermenting comprising
fed-batch fermentation and batch separation; fed-batch fermentation
and continuous separation, or continuous fermentation and
continuous separation.
[0242] In addition to the biosynthesis of 4-HB, 4-HBal, 4-HBCoA,
BDO or putrescine and other products of the invention as described
herein, the non-naturally occurring microbial organisms and methods
of the invention also can be utilized in various combinations with
each other and with other microbial organisms and methods well
known in the art to achieve product biosynthesis by other routes.
For example, one alternative to produce BDO other than use of the
4-HB producers and chemical steps or other than use of the BDO
producer directly is through addition of another microbial organism
capable of converting 4-HB or a 4-HB product exemplified herein to
BDO.
[0243] One such procedure includes, for example, the fermentation
of a 4-HB producing microbial organism of the invention to produce
4-HB, as described above and below. The 4-HB can then be used as a
substrate for a second microbial organism that converts 4-HB to,
for example, BDO, GBL and/or THF. The 4-HB can be added directly to
another culture of the second organism or the original culture of
4-HB producers can be depleted of these microbial organisms by, for
example, cell separation, and then subsequent addition of the
second organism to the fermentation broth can utilized to produce
the final product without intermediate purification steps. One
exemplary second organism having the capacity to biochemically
utilize 4-HB as a substrate for conversion to BDO, for example, is
Clostridium acetobutylicum (see, for example, Jewell et al.,
Current Microbiology, 13:215-19 (1986)).
[0244] Thus, such a procedure includes, for example, the
fermentation of a microbial organism that produces a 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine pathway intermediate. The 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine pathway intermediate can then be used as
a substrate for a second microbial organism that converts the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine pathway intermediate to 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine. The 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine pathway intermediate can be added directly to another
culture of the second organism or the original culture of the 4-HB,
4-HBal, 4-HBCoA BDO or putrescine pathway intermediate producers
can be depleted of these microbial organisms by, for example, cell
separation, and then subsequent addition of the second organism to
the fermentation broth can be utilized to produce the final product
without intermediate purification steps.
[0245] In other embodiments, the non-naturally occurring microbial
organisms and methods of the invention can be assembled in a wide
variety of subpathways to achieve biosynthesis of, for example,
4-HB and/or BDO as described. In these embodiments, biosynthetic
pathways for a desired product of the invention can be segregated
into different microbial organisms and the different microbial
organisms can be co-cultured to produce the final product. In such
a biosynthetic scheme, the product of one microbial organism is the
substrate for a second microbial organism until the final product
is synthesized. For example, the biosynthesis of BDO can be
accomplished as described previously by constructing a microbial
organism that contains biosynthetic pathways for conversion of one
pathway intermediate to another pathway intermediate or the
product, for example, a substrate such as endogenous succinate
through 4-HB to the final product BDO. Alternatively, BDO also can
be biosynthetically produced from microbial organisms through
co-culture or co-fermentation using two organisms in the same
vessel. A first microbial organism being a 4-HB producer with genes
to produce 4-HB from succinic acid, and a second microbial organism
being a BDO producer with genes to convert 4-HB to BDO. For
example, the biosynthesis of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine can be accomplished by constructing a microbial organism
that contains biosynthetic pathways for conversion of one pathway
intermediate to another pathway intermediate or the product.
Alternatively, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine also can be
biosynthetically produced from microbial organisms through
co-culture or co-fermentation using two organisms in the same
vessel, where the first microbial organism produces a 4-HB, 4-HBal,
4-HBCoA, BDO or putrescine intermediate and the second microbial
organism converts the intermediate to 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine.
[0246] Given the teachings and guidance provided herein, those
skilled in the art will understand that a wide variety of
combinations and permutations exist for the non-naturally occurring
microbial organisms and methods of the invention together with
other microbial organisms, with the co-culture of other
non-naturally occurring microbial organisms having subpathways and
with combinations of other chemical and/or biochemical procedures
well known in the art to produce 4-HB, BDO, GBL and THF products of
the invention.
[0247] It is understood that, in methods of the invention, any of
the one or more exogenous nucleic acids can be introduced into a
microbial organism to produce a non-naturally occurring microbial
organism of the invention. The nucleic acids can be introduced so
as to confer, for example, a 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine biosynthetic pathway onto the microbial organism.
Alternatively, encoding nucleic acids can be introduced to produce
an intermediate microbial organism having the biosynthetic
capability to catalyze some of the required reactions to confer
4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic capability.
For example, a non-naturally occurring microbial organism having a
4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway can
comprise at least two exogenous nucleic acids encoding desired
enzymes or proteins, such as the combination of enzymes as
disclosed herein (see Examples and FIGS. 1, 8-13, 58, 62 and 63),
and the like. Thus, it is understood that any combination of two or
more enzymes or proteins of a biosynthetic pathway can be included
in a non-naturally occurring microbial organism of the invention.
Similarly, it is understood that any combination of three or more
enzymes or proteins of a biosynthetic pathway can be included in a
non-naturally occurring microbial organism of the invention, for
example,], and so forth, as desired and disclosed herein, so long
as the combination of enzymes and/or proteins of the desired
biosynthetic pathway results in production of the corresponding
desired product. Similarly, any combination of four or more enzymes
or proteins of a biosynthetic pathway as disclosed herein can be
included in a non-naturally occurring microbial organism of the
invention, as desired, so long as the combination of enzymes and/or
proteins of the desired biosynthetic pathway results in production
of the corresponding desired product.
[0248] To generate better producers, metabolic modeling can be
utilized to optimize growth conditions. Modeling can also be used
to design gene knockouts that additionally optimize utilization of
the pathway (see, for example, U.S. patent publications US
2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US
2003/0059792, US 2002/0168654 and US 2004/0009466, and U.S. Pat.
No. 7,127,379). Modeling analysis allows reliable predictions of
the effects on cell growth of shifting the metabolism towards more
efficient production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine.
[0249] One computational method for identifying and designing
metabolic alterations favoring biosynthesis of a desired product is
the OptKnock computational framework (Burgard et al., Biotechnol.
Bioeng. 84:647-657 (2003)). OptKnock is a metabolic modeling and
simulation program that suggests gene deletion or disruption
strategies that result in genetically stable microorganisms which
overproduce the target product. Specifically, the framework
examines the complete metabolic and/or biochemical network of a
microorganism in order to suggest genetic manipulations that force
the desired biochemical to become an obligatory byproduct of cell
growth. By coupling biochemical production with cell growth through
strategically placed gene deletions or other functional gene
disruption, the growth selection pressures imposed on the
engineered strains after long periods of time in a bioreactor lead
to improvements in performance as a result of the compulsory
growth-coupled biochemical production. Lastly, when gene deletions
are constructed there is a negligible possibility of the designed
strains reverting to their wild-type states because the genes
selected by OptKnock are to be completely removed from the genome.
Therefore, this computational methodology can be used to either
identify alternative pathways that lead to biosynthesis of a
desired product or used in connection with the non-naturally
occurring microbial organisms for further optimization of
biosynthesis of a desired product.
[0250] Briefly, OptKnock is a term used herein to refer to a
computational method and system for modeling cellular metabolism.
The OptKnock program relates to a framework of models and methods
that incorporate particular constraints into flux balance analysis
(FBA) models. These constraints include, for example, qualitative
kinetic information, qualitative regulatory information, and/or DNA
microarray experimental data. OptKnock also computes solutions to
various metabolic problems by, for example, tightening the flux
boundaries derived through flux balance models and subsequently
probing the performance limits of metabolic networks in the
presence of gene additions or deletions. OptKnock computational
framework allows the construction of model formulations that allow
an effective query of the performance limits of metabolic networks
and provides methods for solving the resulting mixed-integer linear
programming problems. The metabolic modeling and simulation methods
referred to herein as OptKnock are described in, for example, U.S.
publication 2002/0168654, filed Jan. 10, 2002, in International
Patent No. PCT/US02/00660, filed Jan. 10, 2002, and U.S.
publication 2009/0047719, filed Aug. 10, 2007.
[0251] Another computational method for identifying and designing
metabolic alterations favoring biosynthetic production of a product
is a metabolic modeling and simulation system termed SimPheny.RTM..
This computational method and system is described in, for example,
U.S. publication 2003/0233218, filed Jun. 14, 2002, and in
International Patent Application No. PCT/US03/18838, filed Jun. 13,
2003. SimPheny.RTM. is a computational system that can be used to
produce a network model in silico and to simulate the flux of mass,
energy or charge through the chemical reactions of a biological
system to define a solution space that contains any and all
possible functionalities of the chemical reactions in the system,
thereby determining a range of allowed activities for the
biological system. This approach is referred to as
constraints-based modeling because the solution space is defined by
constraints such as the known stoichiometry of the included
reactions as well as reaction thermodynamic and capacity
constraints associated with maximum fluxes through reactions. The
space defined by these constraints can be interrogated to determine
the phenotypic capabilities and behavior of the biological system
or of its biochemical components.
[0252] These computational approaches are consistent with
biological realities because biological systems are flexible and
can reach the same result in many different ways. Biological
systems are designed through evolutionary mechanisms that have been
restricted by fundamental constraints that all living systems must
face. Therefore, constraints-based modeling strategy embraces these
general realities. Further, the ability to continuously impose
further restrictions on a network model via the tightening of
constraints results in a reduction in the size of the solution
space, thereby enhancing the precision with which physiological
performance or phenotype can be predicted.
[0253] Given the teachings and guidance provided herein, those
skilled in the art will be able to apply various computational
frameworks for metabolic modeling and simulation to design and
implement biosynthesis of a desired compound in host microbial
organisms. Such metabolic modeling and simulation methods include,
for example, the computational systems exemplified above as
SimPheny.RTM. and OptKnock. For illustration of the invention, some
methods are described herein with reference to the OptKnock
computation framework for modeling and simulation. Those skilled in
the art will know how to apply the identification, design and
implementation of the metabolic alterations using OptKnock to any
of such other metabolic modeling and simulation computational
frameworks and methods well known in the art.
[0254] The methods described above will provide one set of
metabolic reactions to disrupt. Elimination of each reaction within
the set or metabolic modification can result in a desired product
as an obligatory product during the growth phase of the organism.
Because the reactions are known, a solution to the bilevel OptKnock
problem also will provide the associated gene or genes encoding one
or more enzymes that catalyze each reaction within the set of
reactions. Identification of a set of reactions and their
corresponding genes encoding the enzymes participating in each
reaction is generally an automated process, accomplished through
correlation of the reactions with a reaction database having a
relationship between enzymes and encoding genes.
[0255] Once identified, the set of reactions that are to be
disrupted in order to achieve production of a desired product are
implemented in the target cell or organism by functional disruption
of at least one gene encoding each metabolic reaction within the
set. One particularly useful means to achieve functional disruption
of the reaction set is by deletion of each encoding gene. However,
in some instances, it can be beneficial to disrupt the reaction by
other genetic aberrations including, for example, mutation,
deletion of regulatory regions such as promoters or cis binding
sites for regulatory factors, or by truncation of the coding
sequence at any of a number of locations. These latter aberrations,
resulting in less than total deletion of the gene set can be
useful, for example, when rapid assessments of the coupling of a
product are desired or when genetic reversion is less likely to
occur.
[0256] To identify additional productive solutions to the above
described bilevel OptKnock problem which lead to further sets of
reactions to disrupt or metabolic modifications that can result in
the biosynthesis, including growth-coupled biosynthesis of a
desired product, an optimization method, termed integer cuts, can
be implemented. This method proceeds by iteratively solving the
OptKnock problem exemplified above with the incorporation of an
additional constraint referred to as an integer cut at each
iteration. Integer cut constraints effectively prevent the solution
procedure from choosing the exact same set of reactions identified
in any previous iteration that obligatorily couples product
biosynthesis to growth. For example, if a previously identified
growth-coupled metabolic modification specifies reactions 1, 2, and
3 for disruption, then the following constraint prevents the same
reactions from being simultaneously considered in subsequent
solutions. The integer cut method is well known in the art and can
be found described in, for example, Burgard et al., Biotechnol.
Prog. 17:791-797 (2001). As with all methods described herein with
reference to their use in combination with the OptKnock
computational framework for metabolic modeling and simulation, the
integer cut method of reducing redundancy in iterative
computational analysis also can be applied with other computational
frameworks well known in the art including, for example,
SimPheny.RTM..
[0257] The methods exemplified herein allow the construction of
cells and organisms that biosynthetically produce a desired
product, including the obligatory coupling of production of a
target biochemical product to growth of the cell or organism
engineered to harbor the identified genetic alterations. Therefore,
the computational methods described herein allow the identification
and implementation of metabolic modifications that are identified
by an in silico method selected from OptKnock or SimPheny.RTM.. The
set of metabolic modifications can include, for example, addition
of one or more biosynthetic pathway enzymes and/or functional
disruption of one or more metabolic reactions including, for
example, disruption by gene deletion.
[0258] As discussed above, the OptKnock methodology was developed
on the premise that mutant microbial networks can be evolved
towards their computationally predicted maximum-growth phenotypes
when subjected to long periods of growth selection. In other words,
the approach leverages an organism's ability to self-optimize under
selective pressures. The OptKnock framework allows for the
exhaustive enumeration of gene deletion combinations that force a
coupling between biochemical production and cell growth based on
network stoichiometry. The identification of optimal gene/reaction
knockouts requires the solution of a bilevel optimization problem
that chooses the set of active reactions such that an optimal
growth solution for the resulting network overproduces the
biochemical of interest (Burgard et al., Biotechnol. Bioeng.
84:647-657 (2003)).
[0259] An in silico stoichiometric model of E. coli metabolism can
be employed to identify essential genes for metabolic pathways as
exemplified previously and described in, for example, U.S. patent
publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US
2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466,
and in U.S. Pat. No. 7,127,379. As disclosed herein, the OptKnock
mathematical framework can be applied to pinpoint gene deletions
leading to the growth-coupled production of a desired product.
Further, the solution of the bilevel OptKnock problem provides only
one set of deletions. To enumerate all meaningful solutions, that
is, all sets of knockouts leading to growth-coupled production
formation, an optimization technique, termed integer cuts, can be
implemented. This entails iteratively solving the OptKnock problem
with the incorporation of an additional constraint referred to as
an integer cut at each iteration, as discussed above.
[0260] The methods exemplified above and further illustrated in the
Examples below allow the construction of cells and organisms that
biosynthetically produce, including obligatory couple production of
a target biochemical product to growth of the cell or organism
engineered to harbor the identified genetic alterations. In this
regard, metabolic alterations have been identified that result in
the biosynthesis of 4-HB and 1,4-butanediol. Microorganism strains
constructed with the identified metabolic alterations produce
elevated levels of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
compared to unmodified microbial organisms. These strains can be
beneficially used for the commercial production of 4-HB, BDO, THF,
GBL, 4-HBal, 4-HBCoA or putrescine, for example, in continuous
fermentation process without being subjected to the negative
selective pressures.
[0261] Therefore, the computational methods described herein allow
the identification and implementation of metabolic modifications
that are identified by an in silico method selected from OptKnock
or SimPheny.RTM.. The set of metabolic modifications can include,
for example, addition of one or more biosynthetic pathway enzymes
and/or functional disruption of one or more metabolic reactions
including, for example, disruption by gene deletion.
[0262] It is understood that modifications which do not
substantially affect the activity of the various embodiments of
this invention are also included within the definition of the
invention provided herein. Accordingly, the following examples are
intended to illustrate but not limit the present invention.
[0263] Any of the non-naturally occurring microbial organisms
described herein can be cultured to produce and/or secrete the
biosynthetic products of the invention. For example, the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine producers can be cultured for
the biosynthetic production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine.
[0264] For the production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine, the recombinant strains are cultured in a medium with
carbon source and other essential nutrients. It is highly desirable
to maintain anaerobic conditions in the fermenter to reduce the
cost of the overall process. Such conditions can be obtained, for
example, by first sparging the medium with nitrogen and then
sealing the flasks with a septum and crimp-cap. For strains where
growth is not observed anaerobically, microaerobic conditions can
be applied by perforating the septum with a small hole for limited
aeration. Exemplary anaerobic conditions have been described
previously and are well-known in the art. Exemplary aerobic and
anaerobic conditions are described, for example, in U.S.
publication 2009/0047719, filed Aug. 10, 2007. Fermentations can be
performed in a batch, fed-batch or continuous manner, as disclosed
herein.
[0265] If desired, the pH of the medium can be maintained at a
desired pH, in particular neutral pH, such as a pH of around 7 by
addition of a base, such as NaOH or other bases, or acid, as needed
to maintain the culture medium at a desirable pH. The growth rate
can be determined by measuring optical density using a
spectrophotometer (600 nm), and the glucose uptake rate by
monitoring carbon source depletion over time.
[0266] In addition to renewable feedstocks such as those
exemplified above, the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
producing microbial organisms of the invention also can be modified
for growth on syngas as its source of carbon. In this specific
embodiment, one or more proteins or enzymes are expressed in the
4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producing organisms to
provide a metabolic pathway for utilization of syngas or other
gaseous carbon source.
[0267] Synthesis gas, also known as syngas or producer gas, is the
major product of gasification of coal and of carbonaceous materials
such as biomass materials, including agricultural crops and
residues. Syngas is a mixture primarily of H.sub.2 and CO and can
be obtained from the gasification of any organic feedstock,
including but not limited to coal, coal oil, natural gas, biomass,
and waste organic matter. Gasification is generally carried out
under a high fuel to oxygen ratio. Although largely H.sub.2 and CO,
syngas can also include CO.sub.2 and other gases in smaller
quantities. Thus, synthesis gas provides a cost effective source of
gaseous carbon such as CO and, additionally, CO.sub.2.
[0268] The Wood-Ljungdahl pathway catalyzes the conversion of CO
and H.sub.2 to acetyl-CoA and other products such as acetate.
Organisms capable of utilizing CO and syngas also generally have
the capability of utilizing CO.sub.2 and CO.sub.2/H.sub.2 mixtures
through the same basic set of enzymes and transformations
encompassed by the Wood-Ljungdahl pathway. H.sub.2-dependent
conversion of CO.sub.2 to acetate by microorganisms was recognized
long before it was revealed that CO also could be used by the same
organisms and that the same pathways were involved. Many acetogens
have been shown to grow in the presence of CO.sub.2 and produce
compounds such as acetate as long as hydrogen is present to supply
the necessary reducing equivalents (see for example, Drake,
Acetogenesis, pp. 3-60 Chapman and Hall, New York, (1994)). This
can be summarized by the following equation:
2CO.sub.2+4H.sub.2+nADP+nPi.fwdarw.CH.sub.3COOH+2H.sub.2O+nATP
Hence, non-naturally occurring microorganisms possessing the
Wood-Ljungdahl pathway can utilize CO.sub.2 and H.sub.2 mixtures as
well for the production of acetyl-CoA and other desired
products.
[0269] The Wood-Ljungdahl pathway is well known in the art and
consists of 12 reactions which can be separated into two branches:
(1) methyl branch and (2) carbonyl branch. The methyl branch
converts syngas to methyl-tetrahydrofolate (methyl-THF) whereas the
carbonyl branch converts methyl-THF to acetyl-CoA. The reactions in
the methyl branch are catalyzed in order by the following enzymes
or proteins: ferredoxin oxidoreductase, formate dehydrogenase,
formyltetrahydrofolate synthetase, methenyltetrahydrofolate
cyclodehydratase, methylenetetrahydrofolate dehydrogenase and
methylenetetrahydrofolate reductase. The reactions in the carbonyl
branch are catalyzed in order by the following enzymes or proteins:
methyltetrahydrofolate:corrinoid protein methyltransferase (for
example, AcsE), corrinoid iron-sulfur protein, nickel-protein
assembly protein (for example, AcsF), ferredoxin, acetyl-CoA
synthase, carbon monoxide dehydrogenase and nickel-protein assembly
protein (for example, CooC). Following the teachings and guidance
provided herein for introducing a sufficient number of encoding
nucleic acids to generate a 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathway, those skilled in the art will understand that
the same engineering design also can be performed with respect to
introducing at least the nucleic acids encoding the Wood-Ljungdahl
enzymes or proteins absent in the host organism. Therefore,
introduction of one or more encoding nucleic acids into the
microbial organisms of the invention such that the modified
organism contains the complete Wood-Ljungdahl pathway will confer
syngas utilization ability.
[0270] Accordingly, given the teachings and guidance provided
herein, those skilled in the art will understand that a
non-naturally occurring microbial organism can be produced that
secretes the biosynthesized compounds of the invention when grown
on a carbon source such as a carbohydrate. Such compounds include,
for example, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and any of
the intermediate metabolites in the 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine pathway. All that is required is to engineer in one or
more of the required enzyme or protein activities to achieve
biosynthesis of the desired compound or intermediate including, for
example, inclusion of some or all of the 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine biosynthetic pathways. Accordingly, the invention
provides a non-naturally occurring microbial organism that produces
and/or secretes 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine when grown
on a carbohydrate or other carbon source and produces and/or
secretes any of the intermediate metabolites shown in the 4-HB,
4-HBal, 4-HBCoA, BDO or putrescine pathway when grown on a
carbohydrate or other carbon source. The 4-HB, 4-HBal, 4-HBCoA, BDO
or putrescine producing microbial organisms of the invention can
initiate synthesis from an intermediate in a 4-HB, 4-HBal, 4-HBCoA,
BDO or putrescine pathway, as disclosed herein.
[0271] To generate better producers, metabolic modeling can be
utilized to optimize growth conditions. Modeling can also be used
to design gene knockouts that additionally optimize utilization of
the pathway (see, for example, U.S. patent publications US
2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US
2003/0059792, US 2002/0168654 and US 2004/0009466, and U.S. Pat.
No. 7,127,379). Modeling analysis allows reliable predictions of
the effects on cell growth of shifting the metabolism towards more
efficient production of 4-HB, 4-HBal, 4-HBCoA, BDO or
putrescine.
[0272] One computational method for identifying and designing
metabolic alterations favoring biosynthesis of a desired product is
the OptKnock computational framework (Burgard et al., Biotechnol.
Bioeng. 84:647-657 (2003)). OptKnock is a metabolic modeling and
simulation program that suggests gene deletion strategies that
result in genetically stable microorganisms which overproduce the
target product. Specifically, the framework examines the complete
metabolic and/or biochemical network of a microorganism in order to
suggest genetic manipulations that force the desired biochemical to
become an obligatory byproduct of cell growth. By coupling
biochemical production with cell growth through strategically
placed gene deletions or other functional gene disruption, the
growth selection pressures imposed on the engineered strains after
long periods of time in a bioreactor lead to improvements in
performance as a result of the compulsory growth-coupled
biochemical production. Lastly, when gene deletions are constructed
there is a negligible possibility of the designed strains reverting
to their wild-type states because the genes selected by OptKnock
are to be completely removed from the genome. Therefore, this
computational methodology can be used to either identify
alternative pathways that lead to biosynthesis of a desired product
or used in connection with the non-naturally occurring microbial
organisms for further optimization of biosynthesis of a desired
product.
[0273] Briefly, OptKnock is a term used herein to refer to a
computational method and system for modeling cellular metabolism.
The OptKnock program relates to a framework of models and methods
that incorporate particular constraints into flux balance analysis
(FBA) models. These constraints include, for example, qualitative
kinetic information, qualitative regulatory information, and/or DNA
microarray experimental data. OptKnock also computes solutions to
various metabolic problems by, for example, tightening the flux
boundaries derived through flux balance models and subsequently
probing the performance limits of metabolic networks in the
presence of gene additions or deletions. OptKnock computational
framework allows the construction of model formulations that allow
an effective query of the performance limits of metabolic networks
and provides methods for solving the resulting mixed-integer linear
programming problems. The metabolic modeling and simulation methods
referred to herein as OptKnock are described in, for example, U.S.
publication 2002/0168654, filed Jan. 10, 2002, in International
Patent No. PCT/US02/00660, filed Jan. 10, 2002, and U.S.
publication 2009/0047719, filed Aug. 10, 2007.
[0274] Another computational method for identifying and designing
metabolic alterations favoring biosynthetic production of a product
is a metabolic modeling and simulation system termed SimPheny.RTM..
This computational method and system is described in, for example,
U.S. publication 2003/0233218, filed Jun. 14, 2002, and in
International Patent Application No. PCT/US03/18838, filed Jun. 13,
2003. SimPheny.RTM. is a computational system that can be used to
produce a network model in silico and to simulate the flux of mass,
energy or charge through the chemical reactions of a biological
system to define a solution space that contains any and all
possible functionalities of the chemical reactions in the system,
thereby determining a range of allowed activities for the
biological system. This approach is referred to as
constraints-based modeling because the solution space is defined by
constraints such as the known stoichiometry of the included
reactions as well as reaction thermodynamic and capacity
constraints associated with maximum fluxes through reactions. The
space defined by these constraints can be interrogated to determine
the phenotypic capabilities and behavior of the biological system
or of its biochemical components.
[0275] These computational approaches are consistent with
biological realities because biological systems are flexible and
can reach the same result in many different ways. Biological
systems are designed through evolutionary mechanisms that have been
restricted by fundamental constraints that all living systems must
face. Therefore, constraints-based modeling strategy embraces these
general realities. Further, the ability to continuously impose
further restrictions on a network model via the tightening of
constraints results in a reduction in the size of the solution
space, thereby enhancing the precision with which physiological
performance or phenotype can be predicted.
[0276] Given the teachings and guidance provided herein, those
skilled in the art will be able to apply various computational
frameworks for metabolic modeling and simulation to design and
implement biosynthesis of a desired compound in host microbial
organisms. Such metabolic modeling and simulation methods include,
for example, the computational systems exemplified above as
SimPheny.RTM. and OptKnock. For illustration of the invention, some
methods are described herein with reference to the OptKnock
computation framework for modeling and simulation. Those skilled in
the art will know how to apply the identification, design and
implementation of the metabolic alterations using OptKnock to any
of such other metabolic modeling and simulation computational
frameworks and methods well known in the art.
[0277] The methods described above will provide one set of
metabolic reactions to disrupt. Elimination of each reaction within
the set or metabolic modification can result in a desired product
as an obligatory product during the growth phase of the organism.
Because the reactions are known, a solution to the bilevel OptKnock
problem also will provide the associated gene or genes encoding one
or more enzymes that catalyze each reaction within the set of
reactions. Identification of a set of reactions and their
corresponding genes encoding the enzymes participating in each
reaction is generally an automated process, accomplished through
correlation of the reactions with a reaction database having a
relationship between enzymes and encoding genes.
[0278] Once identified, the set of reactions that are to be
disrupted in order to achieve production of a desired product are
implemented in the target cell or organism by functional disruption
of at least one gene encoding each metabolic reaction within the
set. One particularly useful means to achieve functional disruption
of the reaction set is by deletion of each encoding gene. However,
in some instances, it can be beneficial to disrupt the reaction by
other genetic aberrations including, for example, mutation,
deletion of regulatory regions such as promoters or cis binding
sites for regulatory factors, or by truncation of the coding
sequence at any of a number of locations. These latter aberrations,
resulting in less than total deletion of the gene set can be
useful, for example, when rapid assessments of the coupling of a
product are desired or when genetic reversion is less likely to
occur.
[0279] To identify additional productive solutions to the above
described bilevel OptKnock problem which lead to further sets of
reactions to disrupt or metabolic modifications that can result in
the biosynthesis, including growth-coupled biosynthesis of a
desired product, an optimization method, termed integer cuts, can
be implemented. This method proceeds by iteratively solving the
OptKnock problem exemplified above with the incorporation of an
additional constraint referred to as an integer cut at each
iteration. Integer cut constraints effectively prevent the solution
procedure from choosing the exact same set of reactions identified
in any previous iteration that obligatorily couples product
biosynthesis to growth. For example, if a previously identified
growth-coupled metabolic modification specifies reactions 1, 2, and
3 for disruption, then the following constraint prevents the same
reactions from being simultaneously considered in subsequent
solutions. The integer cut method is well known in the art and can
be found described in, for example, Burgard et al., Biotechnol.
Prog. 17:791-797 (2001). As with all methods described herein with
reference to their use in combination with the OptKnock
computational framework for metabolic modeling and simulation, the
integer cut method of reducing redundancy in iterative
computational analysis also can be applied with other computational
frameworks well known in the art including, for example,
SimPheny.RTM..
[0280] The methods exemplified herein allow the construction of
cells and organisms that biosynthetically produce a desired
product, including the obligatory coupling of production of a
target biochemical product to growth of the cell or organism
engineered to harbor the identified genetic alterations. Therefore,
the computational methods described herein allow the identification
and implementation of metabolic modifications that are identified
by an in silico method selected from OptKnock or SimPheny.RTM.. The
set of metabolic modifications can include, for example, addition
of one or more biosynthetic pathway enzymes and/or functional
disruption of one or more metabolic reactions including, for
example, disruption by gene deletion.
[0281] As discussed above, the OptKnock methodology was developed
on the premise that mutant microbial networks can be evolved
towards their computationally predicted maximum-growth phenotypes
when subjected to long periods of growth selection. In other words,
the approach leverages an organism's ability to self-optimize under
selective pressures. The OptKnock framework allows for the
exhaustive enumeration of gene deletion combinations that force a
coupling between biochemical production and cell growth based on
network stoichiometry. The identification of optimal gene/reaction
knockouts requires the solution of a bilevel optimization problem
that chooses the set of active reactions such that an optimal
growth solution for the resulting network overproduces the
biochemical of interest (Burgard et al., Biotechnol. Bioeng.
84:647-657 (2003)).
[0282] An in silico stoichiometric model of E. coli metabolism can
be employed to identify essential genes for metabolic pathways as
exemplified previously and described in, for example, U.S. patent
publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US
2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466,
and in U.S. Pat. No. 7,127,379. As disclosed herein, the OptKnock
mathematical framework can be applied to pinpoint gene deletions
leading to the growth-coupled production of a desired product.
Further, the solution of the bilevel OptKnock problem provides only
one set of deletions. To enumerate all meaningful solutions, that
is, all sets of knockouts leading to growth-coupled production
formation, an optimization technique, termed integer cuts, can be
implemented. This entails iteratively solving the OptKnock problem
with the incorporation of an additional constraint referred to as
an integer cut at each iteration, as discussed above.
[0283] As disclosed herein, a nucleic acid encoding a desired
activity of a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway can
be introduced into a host organism. In some cases, it can be
desirable to modify an activity of a 4-HB, 4-HBal, 4-HBCoA BDO or
putrescine pathway enzyme or protein to increase production of
4-HB, 4-HBal, 4-HBCoA BDO or putrescine. For example, known
mutations that increase the activity of a protein or enzyme can be
introduced into an encoding nucleic acid molecule. Additionally,
optimization methods can be applied to increase the activity of an
enzyme or protein and/or decrease an inhibitory activity, for
example, decrease the activity of a negative regulator.
[0284] One such optimization method is directed evolution. Directed
evolution is a powerful approach that involves the introduction of
mutations targeted to a specific gene in order to improve and/or
alter the properties of an enzyme. Improved and/or altered enzymes
can be identified through the development and implementation of
sensitive high-throughput screening assays that allow the automated
screening of many enzyme variants (for example, >10.sup.4).
Iterative rounds of mutagenesis and screening typically are
performed to afford an enzyme with optimized properties.
Computational algorithms that can help to identify areas of the
gene for mutagenesis also have been developed and can significantly
reduce the number of enzyme variants that need to be generated and
screened. Numerous directed evolution technologies have been
developed (for reviews, see Hibbert et al., Biomol. Eng 22:11-19
(2005); Huisman and Lalonde, In Biocatalysis in the pharmaceutical
and biotechnology industries pgs. 717-742 (2007), Patel (ed.), CRC
Press; Otten and Quax. Biomol. Eng 22:1-9 (2005); and Sen et al.,
Appl Biochem. Biotechnol 143:212-223 (2007)) to be effective at
creating diverse variant libraries, and these methods have been
successfully applied to the improvement of a wide range of
properties across many enzyme classes. Enzyme characteristics that
have been improved and/or altered by directed evolution
technologies include, for example: selectivity/specificity, for
conversion of non-natural substrates; temperature stability, for
robust high temperature processing; pH stability, for bioprocessing
under lower or higher pH conditions; substrate or product
tolerance, so that high product titers can be achieved; binding
(K.sub.m), including broadening substrate binding to include
non-natural substrates; inhibition (K.sub.i), to remove inhibition
by products, substrates, or key intermediates; activity (kcat), to
increases enzymatic reaction rates to achieve desired flux;
expression levels, to increase protein yields and overall pathway
flux; oxygen stability, for operation of air sensitive enzymes
under aerobic conditions; and anaerobic activity, for operation of
an aerobic enzyme in the absence of oxygen.
[0285] A number of exemplary methods have been developed for the
mutagenesis and diversification of genes to target desired
properties of specific enzymes. Such methods are well known to
those skilled in the art. Any of these can be used to alter and/or
optimize the activity of a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine
pathway enzyme or protein. Such methods include, but are not
limited to EpPCR, which introduces random point mutations by
reducing the fidelity of DNA polymerase in PCR reactions (Pritchard
et al., J Theor. Biol. 234:497-509 (2005)); Error-prone Rolling
Circle Amplification (epRCA), which is similar to epPCR except a
whole circular plasmid is used as the template and random 6-mers
with exonuclease resistant thiophosphate linkages on the last 2
nucleotides are used to amplify the plasmid followed by
transformation into cells in which the plasmid is re-circularized
at tandem repeats (Fujii et al., Nucleic Acids Res. 32:e145 (2004);
and Fujii et al., Nat. Protoc. 1:2493-2497 (2006)); DNA or Family
Shuffling, which typically involves digestion of two or more
variant genes with nucleases such as Dnase I or EndoV to generate a
pool of random fragments that are reassembled by cycles of
annealing and extension in the presence of DNA polymerase to create
a library of chimeric genes (Stemmer, Proc Natl Acad Sci USA
91:10747-10751 (1994); and Stemmer, Nature 370:389-391 (1994));
Staggered Extension (StEP), which entails template priming followed
by repeated cycles of 2 step PCR with denaturation and very short
duration of annealing/extension (as short as 5 sec) (Zhao et al.,
Nat. Biotechnol. 16:258-261 (1998)); Random Priming Recombination
(RPR), in which random sequence primers are used to generate many
short DNA fragments complementary to different segments of the
template (Shao et al., Nucleic Acids Res 26:681-683 (1998)).
[0286] Additional methods include Heteroduplex Recombination, in
which linearized plasmid DNA is used to form heteroduplexes that
are repaired by mismatch repair (Volkov et al, Nucleic Acids Res.
27:e18 (1999); and Volkov et al., Methods Enzymol. 328:456-463
(2000)); Random Chimeragenesis on Transient Templates (RACHITT),
which employs Dnase I fragmentation and size fractionation of
single stranded DNA (ssDNA) (Coco et al., Nat. Biotechnol.
19:354-359 (2001)); Recombined Extension on Truncated templates
(RETT), which entails template switching of unidirectionally
growing strands from primers in the presence of unidirectional
ssDNA fragments used as a pool of templates (Lee et al., J. Molec.
Catalysis 26:119-129 (2003)); Degenerate Oligonucleotide Gene
Shuffling (DOGS), in which degenerate primers are used to control
recombination between molecules; (Bergquist and Gibbs, Methods Mol.
Biol 352:191-204 (2007); Bergquist et al., Biomol. Eng 22:63-72
(2005); Gibbs et al., Gene 271:13-20 (2001)); Incremental
Truncation for the Creation of Hybrid Enzymes (ITCHY), which
creates a combinatorial library with 1 base pair deletions of a
gene or gene fragment of interest (Ostermeier et al., Proc. Natl.
Acad. Sci. USA 96:3562-3567 (1999); and Ostermeier et al., Nat.
Biotechnol. 17:1205-1209 (1999)); Thio-Incremental Truncation for
the Creation of Hybrid Enzymes (THIO-ITCHY), which is similar to
ITCHY except that phosphothioate dNTPs are used to generate
truncations (Lutz et al., Nucleic Acids Res 29:E16 (2001));
SCRATCHY, which combines two methods for recombining genes, ITCHY
and DNA shuffling (Lutz et al., Proc. Natl. Acad. Sci. USA
98:11248-11253 (2001)); Random Drift Mutagenesis (RNDM), in which
mutations made via epPCR are followed by screening/selection for
those retaining usable activity (Bergquist et al., Biomol. Eng.
22:63-72 (2005)); Sequence Saturation Mutagenesis (SeSaM), a random
mutagenesis method that generates a pool of random length fragments
using random incorporation of a phosphothioate nucleotide and
cleavage, which is used as a template to extend in the presence of
"universal" bases such as inosine, and replication of an
inosine-containing complement gives random base incorporation and,
consequently, mutagenesis (Wong et al., Biotechnol. J. 3:74-82
(2008); Wong et al., Nucleic Acids Res. 32:e26 (2004); and Wong et
al., Anal. Biochem. 341:187-189 (2005)); Synthetic Shuffling, which
uses overlapping oligonucleotides designed to encode "all genetic
diversity in targets" and allows a very high diversity for the
shuffled progeny (Ness et al., Nat. Biotechnol. 20:1251-1255
(2002)); Nucleotide Exchange and Excision Technology NexT, which
exploits a combination of dUTP incorporation followed by treatment
with uracil DNA glycosylase and then piperidine to perform endpoint
DNA fragmentation (Muller et al., Nucleic Acids Res. 33:e117
(2005)).
[0287] Further methods include Sequence Homology-Independent
Protein Recombination (SHIPREC), in which a linker is used to
facilitate fusion between two distantly related or unrelated genes,
and a range of chimeras is generated between the two genes,
resulting in libraries of single-crossover hybrids (Sieber et al.,
Nat. Biotechnol. 19:456-460 (2001)); Gene Site Saturation
Mutagenesis.TM. (GSSM.TM.), in which the starting materials include
a supercoiled double stranded DNA (dsDNA) plasmid containing an
insert and two primers which are degenerate at the desired site of
mutations (Kretz et al., Methods Enzymol. 388:3-11 (2004));
Combinatorial Cassette Mutagenesis (CCM), which involves the use of
short oligonucleotide cassettes to replace limited regions with a
large number of possible amino acid sequence alterations
(Reidhaar-Olson et al. Methods Enzymol. 208:564-586 (1991); and
Reidhaar-Olson et al. Science 241:53-57 (1988)); Combinatorial
Multiple Cassette Mutagenesis (CMCM), which is essentially similar
to CCM and uses epPCR at high mutation rate to identify hot spots
and hot regions and then extension by CMCM to cover a defined
region of protein sequence space (Reetz et al., Angew. Chem. Int.
Ed Engl. 40:3589-3591 (2001)); the Mutator Strains technique, in
which conditional ts mutator plasmids, utilizing the mutD5 gene,
which encodes a mutant subunit of DNA polymerase III, to allow
increases of 20 to 4000-X in random and natural mutation frequency
during selection and block accumulation of deleterious mutations
when selection is not required (Selifonova et al., Appl. Environ.
Microbiol. 67:3645-3649 (2001)); Low et al., J. Mol. Biol.
260:359-3680 (1996)).
[0288] Additional exemplary methods include Look-Through
Mutagenesis (LTM), which is a multidimensional mutagenesis method
that assesses and optimizes combinatorial mutations of selected
amino acids (Rajpal et al., Proc. Natl. Acad. Sci. USA
102:8466-8471 (2005)); Gene Reassembly, which is a DNA shuffling
method that can be applied to multiple genes at one time or to
create a large library of chimeras (multiple mutations) of a single
gene (Tunable GeneReassembly.TM. (TGR.TM.) Technology supplied by
Verenium Corporation), in Silico Protein Design Automation (PDA),
which is an optimization algorithm that anchors the structurally
defined protein backbone possessing a particular fold, and searches
sequence space for amino acid substitutions that can stabilize the
fold and overall protein energetics, and generally works most
effectively on proteins with known three-dimensional structures
(Hayes et al., Proc. Natl. Acad. Sci. USA 99:15926-15931 (2002));
and Iterative Saturation Mutagenesis (ISM), which involves using
knowledge of structure/function to choose a likely site for enzyme
improvement, performing saturation mutagenesis at chosen site using
a mutagenesis method such as Stratagene QuikChange (Stratagene; San
Diego Calif.), screening/selecting for desired properties, and,
using improved clone(s), starting over at another site and continue
repeating until a desired activity is achieved (Reetz et al., Nat.
Protoc. 2:891-903 (2007); and Reetz et al., Angew. Chem. Int. Ed
Engl. 45:7745-7751 (2006)).
[0289] Any of the aforementioned methods for mutagenesis can be
used alone or in any combination. Additionally, any one or
combination of the directed evolution methods can be used in
conjunction with adaptive evolution techniques, as described
herein.
[0290] It is understood that modifications which do not
substantially affect the activity of the various embodiments of
this invention are also provided within the definition of the
invention provided herein. Accordingly, the following examples are
intended to illustrate but not limit the present invention.
Example I
Biosynthesis of 4-Hydroxybutanoic Acid
[0291] This example describes exemplary biochemical pathways for
4-HB production.
[0292] Previous reports of 4-HB synthesis in microbes have focused
on this compound as an intermediate in production of the
biodegradable plastic poly-hydroxyalkanoate (PHA) (U.S. Pat. No.
6,117,658). The use of 4-HB/3-HB copolymers over
poly-3-hydroxybutyrate polymer (PHB) can result in plastic that is
less brittle (Saito and Doi, Intl. J. Biol. Macromol. 16:99-104
(1994)). The production of monomeric 4-HB described herein is a
fundamentally distinct process for several reasons: (1) the product
is secreted, as opposed to PHA which is produced intracellularly
and remains in the cell; (2) for organisms that produce
hydroxybutanoate polymers, free 4-HB is not produced, but rather
the Coenzyme A derivative is used by the polyhydroxyalkanoate
synthase; (3) in the case of the polymer, formation of the granular
product changes thermodynamics; and (4) extracellular pH is not an
issue for production of the polymer, whereas it will affect whether
4-HB is present in the free acid or conjugate base state, and also
the equilibrium between 4-HB and GBL.
[0293] 4-HB can be produced in two enzymatic reduction steps from
succinate, a central metabolite of the TCA cycle, with succinic
semialdehyde as the intermediate (FIG. 1). The first of these
enzymes, succinic semialdehyde dehydrogenase, is native to many
organisms including E. coli, in which both NADH- and
NADPH-dependent enzymes have been found (Donnelly and Cooper, Eur.
J. Biochem. 113:555-561 (1981); Donnelly and Cooper, J. Bacteriol.
145:1425-1427 (1981); Marek and Henson, J. Bacteriol. 170:991-994
(1988)). There is also evidence supporting succinic semialdehyde
dehydrogenase activity in S. cerevisiae (Ramos et al., Eur. J.
Biochem. 149:401-404 (1985)), and a putative gene has been
identified by sequence homology. However, most reports indicate
that this enzyme proceeds in the direction of succinate synthesis,
as shown in FIG. 1 (Donnelly and Cooper, supra; Lutke-Eversloh and
Steinbuchel, FEMS Microbiol. Lett. 181:63-71 (1999)), participating
in the degradation pathway of 4-HB and gamma-aminobutyrate.
Succinic semialdehyde also is natively produced by certain
microbial organisms such as E. coli through the TCA cycle
intermediate .alpha.-ketogluterate via the action of two enzymes:
glutamate:succinic semialdehyde transaminase and glutamate
decarboxylase. An alternative pathway, used by the obligate
anaerobe Clostridium kluyveri to degrade succinate, activates
succinate to succinyl-CoA, then converts succinyl-CoA to succinic
semialdehyde using an alternative succinic semialdehyde
dehydrogenase which is known to function in this direction (Sohling
and Gottschalk, Eur. J. Biochem. 212:121-127 (1993)). However, this
route has the energetic cost of ATP required to convert succinate
to succinyl-CoA.
[0294] The second enzyme of the pathway, 4-hydroxybutanoate
dehydrogenase, is not native to E. coli or yeast but is found in
various bacteria such as C. kluyveri and Ralstonia eutropha
(Lutke-Eversloh and Steinbuchel, supra; Sohling and Gottschalk, J.
Bacteriol. 178:871-880 (1996); Valentin et al., Eur. J. Biochem.
227:43-60 (1995); Wolff and Kenealy, Protein Expr. Purif. 6:206-212
(1995)). These enzymes are known to be NADH-dependent, though
NADPH-dependent forms also exist. An additional pathway to 4-HB
from alpha-ketoglutarate was demonstrated in E. coli resulting in
the accumulation of poly(4-hydroxybutyric acid) (Song et al., Wei
Sheng Wu Xue. Bao. 45:382-386 (2005)). The recombinant strain
required the overexpression of three heterologous genes, PHA
synthase (R. eutropha), 4-hydroxybutyrate dehydrogenase (R.
eutropha) and 4-hydroxybutyrate:CoA transferase (C. kluyveri),
along with two native E. coli genes: glutamate:succinic
semialdehyde transaminase and glutamate decarboxylase. Steps 4 and
5 in FIG. 1 can alternatively be carried out by an
alpha-ketoglutarate decarboxylase such as the one identified in
Euglena gracilis (Shigeoka et al., Biochem. J. 282(Pt2):319-323
(1992); Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22-28
(1991); Shigeoka and Nakano, Biochem J. 292(Pt 2):463-467 (1993)).
However, this enzyme has not previously been applied to impact the
production of 4-HB or related polymers in any organism.
[0295] The microbial production capabilities of 4-hydroxybutyrate
were explored in two microbes, Escherichia coli and Saccharomyces
cerevisiae, using in silico metabolic models of each organism.
Potential pathways to 4-HB proceed via a succinate, succinyl-CoA,
or alpha-ketoglutarate intermediate as shown in FIG. 1.
[0296] A first step in the 4-HB production pathway from succinate
involves the conversion of succinate to succinic semialdehyde via
an NADH- or NADPH-dependant succinic semialdehyde dehydrogenase. In
E. coli, gabD is an NADP-dependant succinic semialdehyde
dehydrogenase and is part of a gene cluster involved in
4-aminobutyrate uptake and degradation (Niegemann et al., Arch.
Microbiol. 160:454-460 (1993); Schneider et al., J. Bacteriol.
184:6976-6986 (2002)). sad is believed to encode the enzyme for
NAD-dependant succinic semialdehyde dehydrogenase activity (Marek
and Henson, supra). S. cerevisiae contains only the NADPH-dependant
succinic semialdehyde dehydrogenase, putatively assigned to UGA2,
which localizes to the cytosol (Huh et al., Nature 425:686-691
(2003)). The maximum yield calculations assuming the succinate
pathway to 4-HB in both E. coli and S. cerevisiae require only the
assumption that a non-native 4-HB dehydrogenase has been added to
their metabolic networks.
[0297] The pathway from succinyl-CoA to 4-hydroxybutyrate was
described in U.S. Pat. No. 6,117,658 as part of a process for
making polyhydroxyalkanoates comprising 4-hydroxybutyrate monomer
units. Clostridium kluyveri is one example organism known to
possess CoA-dependant succinic semialdehyde dehydrogenase activity
(Sohling and Gottschalk, supra; Sohling and Gottschalk, supra). In
this study, it is assumed that this enzyme, from C. kluyveri or
another organism, is expressed in E. coli or S. cerevisiae along
with a non-native or heterologous 4-HB dehydrogenase to complete
the pathway from succinyl-CoA to 4-HB. The pathway from
alpha-ketoglutarate to 4-HB was demonstrated in E. coli resulting
in the accumulation of poly(4-hydroxybutyric acid) to 30% of dry
cell weight (Song et al., supra). As E. coli and S. cerevisiae
natively or endogenously possess both glutamate:succinic
semialdehyde transaminase and glutamate decarboxylase (Coleman et
al., J. Biol. Chem. 276:244-250 (2001)), the pathway from AKG to
4-HB can be completed in both organisms by assuming only that a
non-native 4-HB dehydrogenase is present.
Example II
Biosynthesis of 1,4-Butanediol from Succinate and
Alpha-Ketoglutarate
[0298] This example illustrates the construction and biosynthetic
production of 4-HB and BDO from microbial organisms. Pathways for
4-HB and BDO are disclosed herein.
[0299] There are several alternative enzymes that can be utilized
in the pathway described above. The native or endogenous enzyme for
conversion of succinate to succinyl-CoA (Step 1 in FIG. 1) can be
replaced by a CoA transferase such as that encoded by the cat1 gene
C. kluyveri (Sohling and Gottschalk, Eur. J Biochem. 212:121-127
(1993)), which functions in a similar manner to Step 9. However,
the production of acetate by this enzyme may not be optimal, as it
might be secreted rather than being converted back to acetyl-CoA.
In this respect, it also can be beneficial to eliminate acetate
formation in Step 9. As one alternative to this CoA transferase, a
mechanism can be employed in which the 4-HB is first phosphorylated
by ATP and then converted to the CoA derivative, similar to the
acetate kinase/phosphotransacetylase pathway in E. coli for the
conversion of acetate to acetyl-CoA. The net cost of this route is
one ATP, which is the same as is required to regenerate acetyl-CoA
from acetate. The enzymes phosphotransbutyrylase (ptb) and butyrate
kinase (bk) are known to carry out these steps on the
non-hydroxylated molecules for butyrate production in C.
acetobutylicum (Cary et al., Appl Environ Microbiol 56:1576-1583
(1990); Valentine, R. C. and R. S. Wolfe, J Biol Chem.
235:1948-1952 (1960)). These enzymes are reversible, allowing
synthesis to proceed in the direction of 4-HB.
[0300] BDO also can be produced via .alpha.-ketoglutarate in
addition to or instead of through succinate. A described
previously, and exemplified further below, one pathway to
accomplish product biosynthesis is with the production of succinic
semialdehyde via .alpha.-ketoglutarate using the endogenous enzymes
(FIG. 1, Steps 4-5). An alternative is to use an
.alpha.-ketoglutarate decarboxylase that can perform this
conversion in one step (FIG. 1, Step 8; Tian et al., Proc Natl Acad
Sci US.A 102:10670-10675 (2005)).
[0301] For the construction of different strains of BDO-producing
microbial organisms, a list of applicable genes was assembled for
corroboration. Briefly, one or more genes within the 4-HB and/or
BDO biosynthetic pathways were identified for each step of the
complete BDO-producing pathway shown in FIG. 1, using available
literature resources, the NCBI genetic database, and homology
searches. The genes cloned and assessed in this study are presented
below in Table 6, along with the appropriate references and URL
citations to the polypeptide sequence. As discussed further below,
some genes were synthesized for codon optimization while others
were cloned via PCR from the genomic DNA of the native or wild-type
organism. For some genes both approaches were used, and in this
case the native genes are indicated by an "n" suffix to the gene
identification number when used in an experiment. Note that only
the DNA sequences differ; the proteins are identical.
TABLE-US-00006 TABLE 6 Genes expressed in host BDO-producting
microbial organisms. Reaction Gene ID number Source number (FIG. 1)
Gene name organism Enzyme name Link to protein sequence Reference
0001 9 Cat2 Clostridium 4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nuccore&id=1228100 1
kluyveri coenzyme A DSM 555 transferase 0002 12/13 adhE Clostridium
Aldehyde/alcohol
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&val=15004739 2
acetobutylicum dehydrogenase ATCC 824 0003 12/13 adhE2 Clostridium
Aldehyde/alcohol
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=NP_149325.1 2
acetobutylicum dehydrogenase ATCC 824 0004 1 Cat1 Clostridium
Succinate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nuccore&id=1228100 1
kluyveri coenzyme A DSM 555 transferase 0008 6 sucD Clostridium
Succinic
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nuccore&id=1228100 1
kluyveri semialdehyde DSM 555 dehydrogenase (CoA-dependent) 0009 7
4-HBd Ralstonia 4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=YP_726053.1 2 eutropha H16
dehydrogenase (NAD-dependent) 0010 7 4-HBd Clostridium
4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nuccore&id=1228100 1
kluyveri dehydrogenase DSM 555 (NAD-dependent) 0011 12/13 adhE E.
coli Aldehyde/alcohol
shigen.nig.ac.jp/ecoli/pec/genes.List.DetailAction.do?fromListFlag=true&f-
eatureType=1&orfId=1219 dehydrogenase 0012 12/13 yqhD E. coli
Aldehyde/alcohol
shigen.nig.ac.jp/ecoli/pec/genes.List.DetailAction.do dehydrogenase
0013 13 bdhB Clostridium Butanol
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=NP_349891.1 2
acetobutylicum dehydrogenase II ATCC 824 0020 11 ptb Clostridium
Phospho-
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=15896327 2
acetobutylicum transbutyrylase ATCC 824 0021 10 buk1 Clostridium
Butyrate kinase I
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=20137334 2
acetobutylicum ATCC 824 0022 10 buk2 Clostridium Butyrate kinase II
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=20137415 2
acetobutylicum ATCC 824 0023 13 adhEm isolated from Alcohol (37)d}
metalibrary dehydrogenase of anaerobic sewage digester microbial
consortia 0024 13 adhE Clostridium Alcohol
genome.jp/dbget-bin/www_bget?cth:Cthe_0423 thermocellum
dehydrogenase 0025 13 ald Clostridium Coenzyme A-
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=49036681
(31)d} beijerinckii acylating aldehyde dehydrogenase 0026 13 bdhA
Clostridium Butanol
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=NP_349892.1 2
acetobutylicum dehydrogenase ATCC 824 0027 12 bld Clostridium
Butyraldehyde
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=31075383 4
saccharoperbutylacetonicum dehydrogenase 0028 13 bdh Clostridium
Butanol
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&id=124221917 4
saccharoperbutylacetonicum dehydrogenase 0029 12/13 adhE
Clostridium Aldehyde/alcohol
genome.jp/dbget-bin/www_bget?ctc:CTC01366 tetani dehydrogenase 0030
12/13 adhE Clostridium Aldehyde/alcohol
genome.jp/dbget-bin/www_bget?cpe:CPE2531 perfringens dehydrogenase
0031 12/13 adhE Clostridium Aldehyde/alcohol
genome.jp/dbget-bin/www_bget?cdf:CD2966 difficile dehydrogenase
0032 8 sucA Mycobacterium .alpha.-ketoglutarate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=YP_977400.1 5 bovis
decarboxylase BCG, Pasteur 0033 9 cat2 Clostridium
4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&val=6249316
aminobutyricum coenzyme A transferase 0034 9 cat2 Porphyromonas
4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=protein&val=34541558
gingivalis coenzyme A W83 transferase 0035 6 sucD Porphyromonas
Succinic ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=NP_904963.1
gingivalis semialdehyde W83 dehydrogenase (CoA-dependent) 0036 7
4-HBd Porphyromonas NAD-dependent
ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=NP_904964.1 gingivalis
4-hydroxybutyrate W83 dehydrogenase 0037 7 gbd Uncultured
4-hydroxybutyrate
ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nuccore&id=5916168 6
bacterium dehydrogenase 0038 1 sucCD E. coli Succinyl-CoA
shigen.nig.ac.jp/ecoli/pec/genes.List.DetailAction.do synthetase
.sup.1Sohling and Gottschalk, Eur. J. Biochem. 212: 121-127 (1993);
Sohling and Gottschalk, J. Bacteriol. 178: 871-880 (1996)
.sup.2Nolling et al., J., J. Bacteriol. 183: 4823-4838 (2001)
.sup.3Pohlmann et al., Nat. Biotechnol. 24: 1257-1262 (2006)
.sup.4Kosaka et al., Biosci. Biotechnol. Biochem. 71: 58-68 (2007)
.sup.5Brosch et al., Proc. Natl. Acad. Sci. U.S.A. 104: 5596-5601
(2007) .sup.6Henne et al., Appl. Environ. Microbiol. 65: 3901-3907
(1999)
[0302] Expression Vector Construction for BDO Pathway.
[0303] Vector backbones and some strains were obtained from Dr.
Rolf Lutz of Expressys (expressys.de/). The vectors and strains are
based on the pZ Expression System developed by Dr. Rolf Lutz and
Prof. Hermann Bujard (Lutz, R. and H. Bujard, Nucleic Acids Res
25:1203-1210 (1997)). Vectors obtained were pZE13luc, pZA33luc,
pZS*13luc and pZE22luc and contained the luciferase gene as a
stuffer fragment. To replace the luciferase stuffer fragment with a
lacZ-alpha fragment flanked by appropriate restriction enzyme
sites, the luciferase stuffer fragment was first removed from each
vector by digestion with EcoRI and XbaI. The lacZ-alpha fragment
was PCR amplified from pUC19 with the following primers:
TABLE-US-00007 lacZalpha-RI (SEQ ID NO: 1)
5'GACGAATTCGCTAGCAAGAGGAGAAGTCGACATGTCCAATTCACTGGC CGTCGTTTTAC3'
lacZalpha 3'BB (SEQ ID NO: 2)
5'-GACCCTAGGAAGCTTTCTAGAGTCGACCTATGCGGCATCAGAGCAG A-3'.
[0304] This generated a fragment with a 5' end of EcoRI site, NheI
site, a Ribosomal Binding Site, a SalI site and the start codon. On
the 3' end of the fragment contained the stop codon, XbaI, HindIII,
and AvrII sites. The PCR product was digested with EcoRI and AvrII
and ligated into the base vectors digested with EcoRI and XbaI
(XbaI and AvrII have compatible ends and generate a non-site).
Because NheI and XbaI restriction enzyme sites generate compatible
ends that can be ligated together (but generate a NheI/XbaI
non-site that is not digested by either enzyme), the genes cloned
into the vectors could be "Biobricked" together
(openwetware.org/wiki/Synthetic_Biology:BioBricks). Briefly, this
method allows joining an unlimited number of genes into the vector
using the same 2 restriction sites (as long as the sites do not
appear internal to the genes), because the sites between the genes
are destroyed after each addition.
[0305] All vectors have the pZ designation followed by letters and
numbers indication the origin of replication, antibiotic resistance
marker and promoter/regulatory unit. The origin of replication is
the second letter and is denoted by E for ColE1, A for p15A and S
for pSC101-based origins. The first number represents the
antibiotic resistance marker (1 for Ampicillin, 2 for Kanamycin, 3
for Chloramphenicol, 4 for Spectinomycin and 5 for Tetracycline).
The final number defines the promoter that regulated the gene of
interest (1 for P.sub.LtetO-1, 2 for P.sub.LlacO-1, 3 for
P.sub.A1lacO-1, and 4 for P.sub.lac/ara-1). The MCS and the gene of
interest follows immediately after. For the work discussed here we
employed two base vectors, pZA33 and pZE13, modified for the
biobricks insertions as discussed above. Once the gene(s) of
interest have been cloned into them, resulting plasmids are
indicated using the four digit gene codes given in Table 6; e.g.,
pZA33-XXXX-YYYY- . . . .
[0306] Host Strain Construction.
[0307] The parent strain in all studies described here is E. coli
K-12 strain MG1655. Markerless deletion strains in adhE, gabD, and
aldA were constructed under service contract by a third party using
the redET method (Datsenko, K. A. and B. L. Wanner, Proc Natl Acad
Sci US.A 97:6640-6645 (2000)). Subsequent strains were constructed
via bacteriophage P1 mediated transduction (Miller, J. Experiments
in Molecular Genetics, Cold Spring Harbor Laboratories, New York
(1973)). Strain C600Z1 (laci.sup.q, PN25-tetR, Sp.sup.R,lacY1,
leuB6,mcrB+, supE44, thi-1, thr-1, tonA21) was obtained from
Expressys and was used as a source of a lacI.sup.q allele for P1
transduction. Bacteriophage P1vir was grown on the C600Z1 E. coli
strain, which has the spectinomycin resistance gene linked to the
lacI.sup.q. The P1 lysate grown on C600Z1 was used to infect MG1655
with selection for spectinomycin resistance. The spectinomycin
resistant colonies were then screened for the linked lacI.sup.q by
determining the ability of the transductants to repress expression
of a gene linked to a P.sub.A1lacO-1 promoter. The resulting strain
was designated MG1655 lacI.sup.q. A similar procedure was used to
introduce lacI.sup.Q into the deletion strains.
[0308] Production of 4-HB from Succinate.
[0309] For construction of a 4-HB producer from succinate, genes
encoding steps from succinate to 4-HB and 4-HB-CoA (1, 6, 7, and 9
in FIG. 1) were assembled onto the pZA33 and pZE13 vectors as
described below. Various combinations of genes were assessed, as
well as constructs bearing incomplete pathways as controls (Tables
7 and 8). The plasmids were then transformed into host strains
containing lacI.sup.Q, which allow inducible expression by addition
of isopropyl .beta.-D-1-thiogalactopyranoside (IPTG). Both
wild-type and hosts with deletions in genes encoding the native
succinic semialdehyde dehydrogenase (step 2 in FIG. 1) were
tested.
[0310] Activity of the heterologous enzymes were first tested in in
vitro assays, using strain MG1655 lacI.sup.Q as the host for the
plasmid constructs containing the pathway genes. Cells were grown
aerobically in LB media (Difco) containing the appropriate
antibiotics for each construct, and induced by addition of IPTG at
1 mM when the optical density (OD600) reached approximately 0.5.
Cells were harvested after 6 hours, and enzyme assays conducted as
discussed below.
[0311] In Vitro Enzyme Assays.
[0312] To obtain crude extracts for activity assays, cells were
harvested by centrifugation at 4,500 rpm (Beckman-Coulter, Allegera
X-15R) for 10 min. The pellets were resuspended in 0.3 mL BugBuster
(Novagen) reagent with benzonase and lysozyme, and lysis proceeded
for 15 minutes at room temperature with gentle shaking. Cell-free
lysate was obtained by centrifugation at 14,000 rpm (Eppendorf
centrifuge 5402) for 30 min at 4.degree. C. Cell protein in the
sample was determined using the method of Bradford et al., Anal.
Biochem. 72:248-254 (1976), and specific enzyme assays conducted as
described below. Activities are reported in Units/mg protein, where
a unit of activity is defined as the amount of enzyme required to
convert 1 .mu.mol of substrate in 1 min. at room temperature. In
general, reported values are averages of at least 3 replicate
assays.
[0313] Succinyl-CoA transferase (Cat1) activity was determined by
monitoring the formation of acetyl-CoA from succinyl-CoA and
acetate, following a previously described procedure Sohling and
Gottschalk, J. Bacteriol. 178:871-880 (1996). Succinyl-CoA
synthetase (SucCD) activity was determined by following the
formation of succinyl-CoA from succinate and CoA in the presence of
ATP. The experiment followed a procedure described by Cha and
Parks, J. Biol. Chem. 239:1961-1967 (1964). CoA-dependent succinate
semialdehyde dehydrogenase (SucD) activity was determined by
following the conversion of NAD to NADH at 340 nm in the presence
of succinate semialdehyde and CoA (Sohling and Gottschalk, Eur. J.
Biochem. 212:121-127 (1993)). 4-HB dehydrogenase (4-HBd) enzyme
activity was determined by monitoring the oxidation of NADH to NAD
at 340 nm in the presence of succinate semialdehyde. The experiment
followed a published procedure Gerhardt et al. Arch. Microbiol.
174:189-199 (2000). 4-HB CoA transferase (Cat2) activity was
determined using a modified procedure from Scherf and Buckel, Appl.
Environ. Microbiol. 57:2699-2702 (1991). The formation of 4-HB-CoA
or butyryl-CoA formation from acetyl-CoA and 4-HB or butyrate was
determined using HPLC.
[0314] Alcohol (ADH) and aldehyde (ALD) dehydrogenase was assayed
in the reductive direction using a procedure adapted from several
literature sources (Durre et al., FEMS Microbiol. Rev. 17:251-262
(1995); Palosaari and Rogers, J. Bacteriol. 170:2971-2976 (1988)
and Welch et al., Arch. Biochem. Biophys. 273:309-318 (1989). The
oxidation of NADH is followed by reading absorbance at 340 nM every
four seconds for a total of 240 seconds at room temperature. The
reductive assays were performed in 100 mM MOPS (adjusted to pH 7.5
with KOH), 0.4 mM NADH, and from 1 to 50 .mu.l of cell extract. The
reaction is started by adding the following reagents: 100 .mu.l of
100 mM acetaldehyde or butyraldehyde for ADH, or 100 .mu.l of 1 mM
acetyl-CoA or butyryl-CoA for ALD. The Spectrophotometer is quickly
blanked and then the kinetic read is started. The resulting slope
of the reduction in absorbance at 340 nM per minute, along with the
molar extinction coefficient of NAD(P)H at 340 nM (6000) and the
protein concentration of the extract, can be used to determine the
specific activity.
[0315] The enzyme activity of PTB is measured in the direction of
butyryl-CoA to butyryl-phosphate as described in Cary et al. J.
Bacteriol. 170:4613-4618 (1988). It provides inorganic phosphate
for the conversion, and follows the increase in free CoA with the
reagent 5,5'-dithiobis-(2-nitrobenzoic acid), or DTNB. DTNB rapidly
reacts with thiol groups such as free CoA to release the
yellow-colored 2-nitro-5-mercaptobenzoic acid (TNB), which absorbs
at 412 nm with a molar extinction coefficient of 14,140 M
cm.sup.-1. The assay buffer contained 150 mM potassium phosphate at
pH 7.4, 0.1 mM DTNB, and 0.2 mM butyryl-CoA, and the reaction was
started by addition of 2 to 50 .mu.L cell extract. The enzyme
activity of BK is measured in the direction of butyrate to
butyryl-phosphate formation at the expense of ATP. The procedure is
similar to the assay for acetate kinase previously described Rose
et al., J. Biol. Chem. 211:737-756 (1954). However we have found
another acetate kinase enzyme assay protocol provided by Sigma to
be more useful and sensitive. This assay links conversion of ATP to
ADP by acetate kinase to the linked conversion of ADP and
phosphoenol pyruvate (PEP) to ATP and pyruvate by pyruvate kinase,
followed by the conversion of pyruvate and NADH to lactate and NAD+
by lactate dehydrogenase. Substituting butyrate for acetate is the
only major modification to allow the assay to follow BK enzyme
activity. The assay mixture contained 80 mM triethanolamine buffer
at pH 7.6, 200 mM sodium butyrate, 10 mM MgCl2, 0.1 mM NADH, 6.6 mM
ATP, 1.8 mM phosphoenolpyruvate. Pyruvate kinase, lactate
dehydrogenase, and myokinase were added according to the
manufacturer's instructions. The reaction was started by adding 2
to 50 .mu.L cell extract, and the reaction was monitored based on
the decrease in absorbance at 340 nm indicating NADH oxidation.
[0316] Analysis of CoA Derivatives by HPLC.
[0317] An HPLC based assay was developed to monitor enzymatic
reactions involving coenzyme A (CoA) transfer. The developed method
allowed enzyme activity characterization by quantitative
determination of CoA, acetyl CoA (AcCoA), butyryl CoA (BuCoA) and
4-hydroxybutyrate CoA (4-HBCoA) present in in-vitro reaction
mixtures. Sensitivity down to low .mu.M was achieved, as well as
excellent resolution of all the CoA derivatives of interest.
[0318] Chemical and sample preparation was performed as follows.
Briefly, CoA, AcCoA, BuCoA and all other chemicals, were obtained
from Sigma-Aldrich. The solvents, methanol and acetonitrile, were
of HPLC grade. Standard calibration curves exhibited excellent
linearity in the 0.01-1 mg/mL concentration range. Enzymatic
reaction mixtures contained 100 mM Tris HCl buffer (pH 7), aliquots
were taken at different time points, quenched with formic acid
(0.04% final concentration) and directly analyzed by HPLC.
[0319] HPLC analysis was performed using an Agilent 1100 HPLC
system equipped with a binary pump, degasser, thermostated
autosampler and column compartment, and diode array detector (DAD),
was used for the analysis. A reversed phase column, Kromasil 100
Sum C18, 4.6.times.150 mm (Peeke Scientific), was employed. 25 mM
potassium phosphate (pH 7) and methanol or acetonitrile, were used
as aqueous and organic solvents at 1 mL/min flow rate. Two methods
were developed: a short one with a faster gradient for the analysis
of well-resolved CoA, AcCoA and BuCoA, and a longer method for
distinguishing between closely eluting AcCoA and 4-HBCoA. Short
method employed acetonitrile gradient (0 min-5%, 6 min-30%, 6.5
min-5%, 10 min-5%) and resulted in the retention times 2.7, 4.1 and
5.5 min for CoA, AcCoA and BuCoA, respectively. In the long method
methanol was used with the following linear gradient: 0 min-5%, 20
min-35%, 20.5 min-5%, 25 min-5%. The retention times for CoA,
AcCoA, 4-HBCoA and BuCoA were 5.8, 8.4, 9.2 and 16.0 min,
respectively. The injection volume was 5 .mu.L, column temperature
30.degree. C., and UV absorbance was monitored at 260 nm.
[0320] The results demonstrated activity of each of the four
pathway steps (Table 7), though activity is clearly dependent on
the gene source, position of the gene in the vector, and the
context of other genes with which it is expressed. For example,
gene 0035 encodes a succinic semialdehyde dehydrogenase that is
more active than that encoded by 0008, and 0036 and 0010n are more
active 4-HB dehydrogenase genes than 0009. There also seems to be
better 4-HB dehydrogenase activity when there is another gene
preceding it on the same operon.
TABLE-US-00008 TABLE 7 In vitro enzyme activities in cell extracts
from MG1655 lacI.sup.Q containing the plasmids expressing genes in
the 4-HB-CoA pathway. Activities are reported in Units/mg protein,
where a unit of activity is defined as the amount of enzyme
required to convert 1 .mu.mol of substrate in 1 min. at room
temperature. Sample # pZE13 (a) pZA33 (b) OD600 Cell Prot (c) Cat1
SucD 4HBd Cat2 1 cat1 (0004) 2.71 6.43 1.232 0.00 2 cat1
(0004)-sucD (0035) 2.03 5.00 0.761 2.57 3 cat1 (0004)-sucD (0008)
1.04 3.01 0.783 0.01 4 sucD (0035) 2.31 6.94 2.32 5 sucD (0008)
1.10 4.16 0.05 6 4hbd (0009) 2.81 7.94 0.003 0.25 7 4hbd (0036)
2.63 7.84 3.31 8 4hbd (0010n) 2.00 5.08 2.57 9 cat1 (0004)-sucD
(0035) 4hbd (0009) 2.07 5.04 0.600 1.85 0.01 10 cat1 (0004)-sucD
(0035) 4hbd (0036) 2.08 5.40 0.694 1.73 0.41 11 cat1 (0004)-sucD
(0035) 4hbd (0010n) 2.44 4.73 0.679 2.28 0.37 12 cat1 (0004)-sucD
(0008) 4hbd (0009) 1.08 3.99 0.572 -0.01 0.02 13 cat1 (0004)-sucD
(0008) 4hbd (0036) 0.77 2.60 0.898 -0.01 0.04 14 cat1 (0004)-sucD
(0008) 4hbd (0010n) 0.63 2.47 0.776 0.00 0.00 15 cat2 (0034) 2.56
7.86 1.283 16 cat2(0034)-4hbd(0036) 3.13 8.04 24.86 0.993 17
cat2(0034)-4hbd(0010n) 2.38 7.03 7.45 0.675 18
4hbd(0036)-cat2(0034) 2.69 8.26 2.15 7.490 19
4hbd(0010n)-cat2(0034) 2.44 6.59 0.59 4.101 (a) Genes expressed
from Plac on pZE13, a high-copy plasmid with colE1 origin and
ampicillin resistance. Gene identification numbers are as given in
Table 6 (b) Genes expressed from Plac on pZA33, a medium-copy
plasmid with pACYC origin and chloramphenicol resistance. (c) Cell
protein given as mg protein per mL extract.
[0321] Recombinant strains containing genes in the 4-HB pathway
were then evaluated for the ability to produce 4-HB in vivo from
central metabolic intermediates. Cells were grown anaerobically in
LB medium to OD600 of approximately 0.4, then induced with 1 mM
IPTG. One hour later, sodium succinate was added to 10 mM, and
samples taken for analysis following an additional 24 and 48 hours.
4-HB in the culture broth was analyzed by GC-MS as described below.
The results indicate that the recombinant strain can produce over 2
mM 4-HB after 24 hours, compared to essentially zero in the control
strain (Table 8).
TABLE-US-00009 TABLE 8 Production of 4-HB from succinate in E. coli
strains harboring plasmids expressing various combinations of 4-HB
pathway genes. 24 Hours 48 Hours 4HB, 4HB 4HB, 4HB Sample # Host
Strain pZE13 pZA33 OD600 .mu.M norm. (a) OD600 .mu.M norm. (a) 1
MG1655 laclq cat1 (0004)-sucD (0035) 4hbd (0009) 0.47 487 1036 1.04
1780 1711 2 MG1655 laclq cat1 (0004)-sucD (0035) 4hbd (0027) 0.41
111 270 0.99 214 217 3 MG1655 laclq cat1 (0004)-sucD (0035) 4hbd
(0036) 0.47 863 1835 0.48 2152 4484 4 MG1655 laclq cat1 (0004)-sucD
(0035) 4hbd (0010n) 0.46 956 2078 0.49 2221 4533 5 MG1655 laclq
cat1 (0004)-sucD (0008) 4hbd (0009) 0.38 493 1296 0.37 1338 3616 6
MG1655 laclq cat1 (0004)-sucD (0008) 4hbd (0027) 0.32 26 81 0.27 87
323 7 MG1655 laclq cat1 (0004)-sucD (0008) 4hbd (0036) 0.24 506
2108 0.31 1448 4672 8 MG1655 laclq cat1 (0004)-sucD (0008) 4hbd
(0010n) 0.24 78 324 0.56 233 416 9 MG1655 laclq gabD cat1
(0004)-sucD (0035) 4hbd (0009) 0.53 656 1237 1.03 1643 1595 10
MG1655 laclq gabD cat1 (0004)-sucD (0035) 4hbd (0027) 0.44 92 209
0.98 214 218 11 MG1655 laclq gabD cat1 (0004)-sucD (0035) 4hbd
(0036) 0.51 1072 2102 0.97 2358 2431 12 MG1655 laclq gabD cat1
(0004)-sucD (0035) 4hbd (0010n) 0.51 981 1924 0.97 2121 2186 13
MG1655 laclq gabD cat1 (0004)-sucD (0008) 4hbd (0009) 0.35 407 1162
0.77 1178 1530 14 MG1655 laclq gabD cat1 (0004)-sucD (0008) 4hbd
(0027) 0.51 19 36 1.07 50 47 15 MG1655 laclq gabD cat1 (0004)-sucD
(0008) 4hbd (0036) 0.35 584 1669 0.78 1350 1731 16 MG1655 laclq
gabD cat1 (0004)-sucD (0008) 4hbd (0010n) 0.32 74 232 0.82 232 283
17 MG1655 laclq vector only vector only 0.8 1 2 1.44 3 2 18 MG1655
laclq gabD vector only vector only 0.89 1 2 1.41 7 5 (a) Normalized
4-HB concentration, .mu.M/OD600 units
[0322] An alternate to using a CoA transferase (cat1) to produce
succinyl-CoA from succinate is to use the native E. coli sucCD
genes, encoding succinyl-CoA synthetase. This gene cluster was
cloned onto pZE13 along with candidate genes for the remaining
steps to 4-HB to create pZE13-0038-0035-0036.
[0323] Production of 4-HB from Glucose.
[0324] Although the above experiments demonstrate a functional
pathway to 4-HB from a central metabolic intermediate (succinate),
an industrial process would require the production of chemicals
from low-cost carbohydrate feedstocks such as glucose or sucrose.
Thus, the next set of experiments was aimed to determine whether
endogenous succinate produced by the cells during growth on glucose
could fuel the 4-HB pathway. Cells were grown anaerobically in M9
minimal medium (6.78 g/L Na.sub.2HPO.sub.4, 3.0 g/L
KH.sub.2PO.sub.4, 0.5 g/L NaCl, 1.0 g/L NH.sub.4Cl, 1 mM
MgSO.sub.4, 0.1 mM CaCl.sub.2) supplemented with 20 g/L glucose,
100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the
buffering capacity, 10 .mu.g/mL thiamine, and the appropriate
antibiotics. 0.25 mM IPTG was added when OD600 reached
approximately 0.2, and samples taken for 4-HB analysis every 24
hours following induction. In all cases 4-HB plateaued after 24
hours, with a maximum of about 1 mM in the best strains (FIG. 3a),
while the succinate concentration continued to rise (FIG. 3b). This
indicates that the supply of succinate to the pathway is likely not
limiting, and that the bottleneck may be in the activity of the
enzymes themselves or in NADH availability. 0035 and 0036 are
clearly the best gene candidates for CoA-dependent succinic
semialdehyde dehydrogenase and 4-HB dehydrogenase, respectively.
The elimination of one or both of the genes encoding known (gabD)
or putative (aldA) native succinic semialdehyde dehydrogenases had
little effect on performance. Finally, it should be noted that the
cells grew to a much lower OD in the 4-HB-producing strains than in
the controls (FIG. 3c).
[0325] An alternate pathway for the production of 4-HB from glucose
is via .alpha.-ketoglutarate. We explored the use of an
.alpha.-ketoglutarate decarboxylase from Mycobacterium tuberculosis
Tian et al., Proc. Natl. Acad. Sci. USA 102:10670-10675 (2005) to
produce succinic semialdehyde directly from .alpha.-ketoglutarate
(step 8 in FIG. 1). To demonstrate that this gene (0032) was
functional in vivo, we expressed it on pZE13 in the same host as
4-HB dehydrogenase (gene 0036) on pZA33. This strain was capable of
producing over 1.0 mM 4-HB within 24 hours following induction with
1 mM IPTG (FIG. 4). Since this strain does not express a
CoA-dependent succinic semialdehyde dehydrogenase, the possibility
of succinic semialdehyde production via succinyl-CoA is eliminated.
It is also possible that the native genes responsible for producing
succinic semialdehyde could function in this pathway (steps 4 and 5
in FIG. 1); however, the amount of 4-HB produced when the
pZE13-0032 plasmid was left out of the host is the negligible.
[0326] Production of BDO from 4-HB.
[0327] The production of BDO from 4-HB required two reduction
steps, catalyzed by dehydrogenases. Alcohol and aldehyde
dehydrogenases (ADH and ALD, respectively) are NAD+/H and/or
NADP+/H-dependent enzymes that together can reduce a carboxylic
acid group on a molecule to an alcohol group, or in reverse, can
perform the oxidation of an alcohol to a carboxylic acid. This
biotransformation has been demonstrated in wild-type Clostridium
acetobutylicum (Jewell et al., Current Microbiology, 13:215-19
(1986)), but neither the enzymes responsible nor the genes
responsible were identified. In addition, it is not known whether
activation to 4-HB-CoA is first required (step 9 in FIG. 1), or if
the aldehyde dehydrogenase (step 12) can act directly on 4-HB. We
developed a list of candidate enzymes from C. acetobutylicum and
related organisms based on known activity with the non-hydroxylated
analogues to 4-HB and pathway intermediates, or by similarity to
these characterized genes (Table 6). Since some of the candidates
are multifunctional dehydrogenases, they could potentially catalyze
both the NAD(P)H-dependent reduction of the acid (or
CoA-derivative) to the aldehyde, and of the aldehyde to the
alcohol. Before beginning work with these genes in E. coli, we
first validated the result referenced above using C. acetobutylicum
ATCC 824. Cells were grown in Schaedler broth (Accumedia, Lansing,
Mich.) supplemented with 10 mM 4-HB, in an anaerobic atmosphere of
10% CO.sub.2, 10% H.sub.2, and 80% N.sub.2 at 30.degree. C.
Periodic culture samples were taken, centrifuged, and the broth
analyzed for BDO by GC-MS as described below. BDO concentrations of
0.1 mM, 0.9 mM, and 1.5 mM were detected after 1 day, 2 days, and 7
days incubation, respectively. No BDO was detected in culture grown
without 4-HB addition. To demonstrate that the BDO produced was
derived from glucose, we grew the best BDO producing strain MG1655
lacI.sup.Q pZE13-0004-0035-0002 pZA33-0034-0036 in M9 minimal
medium supplemented with 4 g/L uniformly labeled .sup.13C-glucose.
Cells were induced at OD of 0.67 with 1 mM IPTG, and a sample taken
after 24 hours. Analysis of the culture supernatant was performed
by mass spectrometry.
[0328] Gene candidates for the 4-HB to BDO conversion pathway were
next tested for activity when expressed in the E. coli host MG1655
lacI.sup.Q. Recombinant strains containing each gene candidate
expressed on pZA33 were grown in the presence of 0.25 mM IPTG for
four hours at 37.degree. C. to fully induce expression of the
enzyme. Four hours after induction, cells were harvested and
assayed for ADH and ALD activity as described above. Since 4-HB-CoA
and 4-hydroxybutyraldehyde are not available commercially, assays
were performed using the non-hydroxylated substrates (Table 9). The
ratio in activity between 4-carbon and 2-carbon substrates for C.
acetobutylicum adhE2 (0002) and E. coli adhE (0011) were similar to
those previously reported in the literature a Atsumi et al.,
Biochim. Biophys. Acta. 1207:1-11 (1994).
TABLE-US-00010 TABLE 9 In vitro enzyme activities in cell extracts
from MG1655 lacI.sup.Q containing pZA33 expressing gene candidates
for aldehyde and alcohol dehydrogenases. Aldehyde dehydrogenase
Alcohol dehydrogenase Substrate Gene Butyryl-CoA Acetyl-CoA
Butyraldehyde Acetaldehyde 0002 0.0076 0.0046 0.0264 0.0247 0003n
0.0060 0.0072 0.0080 0.0075 0011 0.0069 0.0095 0.0265 0.0093 0013
N.D. N.D. 0.0130 0.0142 0023 0.0089 0.0137 0.0178 0.0235 0025 0
0.0001 N.D. N.D. 0026 0 0.0005 0.0024 0.0008 Activities are
expressed in .mu.mol min.sup.-1 mg cell protein.sup.-1. N.D., not
determined.
[0329] For the BDO production experiments, cat2 from Porphyromonas
gingivalis W83 (gene 0034) was included on pZA33 for the conversion
of 4-HB to 4-HB-CoA, while the candidate dehydrogenase genes were
expressed on pZE13. The host strain was MG1655 lacI.sup.Q. Along
with the alcohol and aldehyde dehydrogenase candidates, we also
tested the ability of CoA-dependent succinic semialdehyde
dehydrogenases (sucD) to function in this step, due to the
similarity of the substrates. Cells were grown to an OD of about
0.5 in LB medium supplemented with 10 mM 4-HB, induced with 1 mM
IPTG, and culture broth samples taken after 24 hours and analyzed
for BDO as described below. The best BDO production occurred using
adhE2 from C. acetobutylicum, sucD from C. kluyveri, or sucD from
P. gingivalis (FIG. 5). Interestingly, the absolute amount of BDO
produced was higher under aerobic conditions; however, this is
primarily due to the lower cell density achieved in anaerobic
cultures. When normalized to cell OD, the BDO production per unit
biomass is higher in anaerobic conditions (Table 10).
TABLE-US-00011 TABLE 10 Absolute and normalized BDO concentrations
from cultures of cells expressing adhE2 from C. acetobutylicum,
sucD from C. kluyveri, or sucD from P. gingivalis (data from
experiments 2, 9, and 10 in FIG. 3), as well as the negative
control (experiment 1). Gene BDO OD expressed Conditions (.mu.M)
(600 nm) BDO/OD none Aerobic 0 13.4 0 none Microaerobic 0.5 6.7
0.09 none Anaerobic 2.2 1.26 1.75 0002 Aerobic 138.3 9.12 15.2 0002
Microaerobic 48.2 5.52 8.73 0002 Anaerobic 54.7 1.35 40.5 0008n
Aerobic 255.8 5.37 47.6 0008n Microaerobic 127.9 3.05 41.9 0008n
Anaerobic 60.8 0.62 98.1 0035 Aerobic 21.3 14.0 1.52 0035
Microaerobic 13.1 4.14 3.16 0035 Anaerobic 21.3 1.06 20.1
[0330] As discussed above, it may be advantageous to use a route
for converting 4-HB to 4-HB-CoA that does not generate acetate as a
byproduct. To this aim, we tested the use of phosphotransbutyrylase
(ptb) and butyrate kinase (bk) from C. acetobutylicum to carry out
this conversion via steps 10 and 11 in FIG. 1. The native ptb/bk
operon from C. acetobutylicum (genes 0020 and 0021) was cloned and
expressed in pZA33. Extracts from cells containing the resulting
construct were taken and assayed for the two enzyme activities as
described herein. The specific activity of BK was approximately 65
U/mg, while the specific activity of PTB was approximately 5 U/mg.
One unit (U) of activity is defined as conversion of 1 .mu.M
substrate in 1 minute at room temperature. Finally, the construct
was tested for participation in the conversion of 4-HB to BDO. Host
strains were transformed with the pZA33-0020-0021 construct
described and pZE13-0002, and compared to use of cat2 in BDO
production using the aerobic procedure used above in FIG. 5. The
BK/PTB strain produced 1 mM BDO, compared to 2 mM when using cat2
(Table 11). Interestingly, the results were dependent on whether
the host strain contained a deletion in the native adhE gene.
TABLE-US-00012 TABLE 11 Absolute and normalized BDO concentrations
from cultures of cells expressing adhE2 from C. acetobutylicum in
pZE13 along with either cat2 from P. gingivalis (0034) or the
PTB/BK genes from C. acetobutylicum on pZA33. Host strains were
either MG1655 lacI.sup.Q or MG1655 .DELTA.adhE lacI.sup.Q. BDO OD
Genes Host Strain (.mu.M) (600 nm) BDO/OD 0034 MG1655 lacI.sup.Q
0.827 19.9 0.042 0020 + 0021 MG1655 lacI.sup.Q 0.007 9.8 0.0007
0034 MG1655 .DELTA.adhE 2.084 12.5 0.166 lacI.sup.Q 0020 + 0021
MG1655 .DELTA.adhE 0.975 18.8 0.052 lacI.sup.Q
[0331] Production of BDO from Glucose.
[0332] The final step of pathway corroboration is to express both
the 4-HB and BDO segments of the pathway in E. coli and demonstrate
production of BDO in glucose minimal medium. New plasmids were
constructed so that all the required genes fit on two plasmids. In
general, cat1, adhE, and sucD genes were expressed from pZE13, and
cat2 and 4-HBd were expressed from pZA33. Various combinations of
gene source and gene order were tested in the MG1655 lacI.sup.Q
background. Cells were grown anaerobically in M9 minimal medium
(6.78 g/L Na.sub.2HPO.sub.4, 3.0 g/L KH.sub.2PO.sub.4, 0.5 g/L
NaCl, 1.0 g/L NH.sub.4Cl, 1 mM MgSO.sub.4, 0.1 mM CaCl.sub.2)
supplemented with 20 g/L glucose, 100 mM
3-(N-morpholino)propanesulfonic acid (MOPS) to improve the
buffering capacity, 10 .mu.g/mL thiamine, and the appropriate
antibiotics. 0.25 mM IPTG was added approximately 15 hours
following inoculation, and culture supernatant samples taken for
BDO, 4-HB, and succinate analysis 24 and 48 hours following
induction. The production of BDO appeared to show a dependency on
gene order (Table 12). The highest BDO production, over 0.5 mM, was
obtained with cat2 expressed first, followed by 4-HBd on pZA33, and
cat1 followed by P. gingivalis sucD on pZE13. The addition of C.
acetobutylicum adhE2 in the last position on pZE13 resulted in
slight improvement. 4-HB and succinate were also produced at higher
concentrations.
TABLE-US-00013 TABLE 12 Production of BDO, 4-HB, and succinate in
recombinant E. coli strains expressing combinations of BDO pathway
genes, grown in minimal medium supplemented with 20 g/L glucose.
Concentrations are given in mM. 24 Hours 48 Hours Sample pZE13
pZA33 Induction OD OD600nm Su 4HB BDO OD600nm Su 4HB BDO 1
cat1(0004)-sucD(0035) 4hbd (0036)-cat2(0034) 0.92 1.29 5.44 1.37
0.240 1.24 6.42 1.49 0.280 2 cat1(0004)-sucD(0008N) 4hbd
(0036)-cat2(0034) 0.36 1.11 6.90 1.24 0.011 1.06 7.63 1.33 0.011 3
adhE(0002)-cat1(0004)- 4hbd (0036)-cat2(0034) 0.20 0.44 0.34 1.84
0.050 0.60 1.93 2.67 0.119 sucD(0035) 4 cat1(0004)-sucD(0035)- 4hbd
(0036)-cat2(0034) 1.31 1.90 9.02 0.73 0.073 1.95 9.73 0.82 0.077
adhE(0002) 5 adhE(0002)-cat1(0004)- 4hbd (0036)-cat2(0034) 0.17
0.45 1.04 1.04 0.008 0.94 7.13 1.02 0.017 sucD(0008N) 6
cat1(0004)-sucD(0008N)- 4hbd (0036)-cat2(0034) 1.30 1.77 10.47 0.25
0.004 1.80 11.49 0.28 0.003 adhE(0002) 7 cat1(0004)-sucD(0035)
cat2(0034)-4hbd(0036) 1.09 1.29 5.63 2.15 0.461 1.38 6.66 2.30
0.520 8 cat1(0004)-sucD(0008N) cat2(0034)-4hbd(0036) 1.81 2.01
11.28 0.02 0.000 2.24 11.13 0.02 0.000 9 adhE(0002)-cat1(0004)-
cat2(0034)-4hbd(0036) 0.24 1.99 2.02 2.32 0.106 0.89 4.85 2.41
0.186 sucD(0035) 10 cat1(0004)-sucD(0035)- cat2(0034)-4hbd(0036)
0.98 1.17 5.30 2.08 0.569 1.33 6.15 2.14 0.640 adhE(0002) 11
adhE(0002)-cat1(0004)- cat2(0034)-4hbd(0036) 0.20 0.53 1.38 2.30
0.019 0.91 8.10 1.49 0.034 sucD(0008N) 12 cat1(0004)-sucD(0008N)-
cat2(0034)-4hbd(0036) 2.14 2.73 12.07 0.16 0.000 3.10 11.79 0.17
0.002 adhE(0002) 13 vector only vector only 2.11 2.62 9.03 0.01
0.000 3.00 12.05 0.01 0.000
[0333] Analysis of BDO, 4-HB and Succinate by GCMS.
[0334] BDO, 4-HB and succinate in fermentation and cell culture
samples were derivatized by silylation and quantitatively analyzed
by GCMS using methods adapted from literature reports ((Simonov et
al., J. Anal Chem. 59:965-971 (2004)). The developed method
demonstrated good sensitivity down to 1 .mu.M, linearity up to at
least 25 mM, as well as excellent selectivity and
reproducibility.
[0335] Sample preparation was performed as follows: 1000 .mu.L
filtered (0.2 .mu.m or 0.45 .mu.m syringe filters) samples, e.g.
fermentation broth, cell culture or standard solutions, were dried
down in a Speed Vac Concentrator (Savant SVC-100H) for
approximately 1 hour at ambient temperature, followed by the
addition of 20 .mu.L, 10 mM cyclohexanol solution, as an internal
standard, in dimethylformamide. The mixtures were vortexed and
sonicated in a water bath (Branson 3510) for 15 min to ensure
homogeneity. 100 .mu.L silylation derivatization reagent,
N,O-bis(trimethylsilyl)triflouro-acetimide (BSTFA) with 1%
trimethylchlorosilane, was added, and the mixture was incubated at
70.degree. C. for 30 min. The derivatized samples were centrifuged
for 5 min, and the clear solutions were directly injected into
GCMS. All the chemicals and reagents were from Sigma-Aldrich, with
the exception of BDO which was purchased from J.T. Baker.
[0336] GCMS was performed on an Agilent gas chromatograph 6890N,
interfaced to a mass-selective detector (MSD) 5973N operated in
electron impact ionization (EI) mode has been used for the
analysis. A DB-5MS capillary column (J&W Scientific, Agilent
Technologies), 30 m.times.0.25 mm i.d..times.0.25 .mu.m film
thickness, was used. The GC was operated in a split injection mode
introducing 1 .mu.L of sample at 20:1 split ratio. The injection
port temperature was 250.degree. C. Helium was used as a carrier
gas, and the flow rate was maintained at 1.0 mL/min. A temperature
gradient program was optimized to ensure good resolution of the
analytes of interest and minimum matrix interference. The oven was
initially held at 80.degree. C. for 1 min, then ramped to
120.degree. C. at 2.degree. C./min, followed by fast ramping to
320.degree. C. at 100.degree. C./min and final hold for 6 min at
320.degree. C. The MS interface transfer line was maintained at
280.degree. C. The data were acquired using lowmass' MS tune
settings and 30-400 m/z mass-range scan. The total analysis time
was 29 min including 3 min solvent delay. The retention times
corresponded to 5.2, 10.5, 14.0 and 18.2 min for BSTFA-derivatized
cyclohexanol, BDO, 4-HB and succinate, respectively. For
quantitative analysis, the following specific mass fragments were
selected (extracted ion chromatograms): m/z 157 for internal
standard cyclohexanol, 116 for BDO, and 147 for both 4-HB and
succinate. Standard calibration curves were constructed using
analyte solutions in the corresponding cell culture or fermentation
medium to match sample matrix as close as possible. GCMS data were
processed using Environmental Data Analysis ChemStation software
(Agilent Technologies).
[0337] The results indicated that most of the 4-HB and BDO produced
were labeled with .sup.13C (FIG. 6, right-hand sides). Mass spectra
from a parallel culture grown in unlabeled glucose are shown for
comparison (FIG. 6, left-hand sides). Note that the peaks seen are
for fragments of the derivatized molecule containing different
numbers of carbon atoms from the metabolite. The derivatization
reagent also contributes some carbon and silicon atoms that
naturally-occurring label distribution, so the results are not
strictly quantitative.
[0338] Production of BDO from 4-HB Using Alternate Pathways.
[0339] The various alternate pathways were also tested for BDO
production. This includes use of the native E. coli SucCD enzyme to
convert succinate to succinyl-CoA (Table 13, rows 2-3), use of
.alpha.-ketoglutarate decarboxylase in the .alpha.-ketoglutarate
pathway (Table 13, row 4), and use of PTB/BK as an alternate means
to generate the CoA-derivative of 4HB (Table 13, row 1). Strains
were constructed containing plasmids expressing the genes indicated
in Table 13, which encompass these variants. The results show that
in all cases, production of 4-HB and BDO occurred (Table 13).
TABLE-US-00014 TABLE 13 Production of BDO, 4-HB, and succinate in
recombinant E. coli strains genes for different BDO pathway
variants, grown anaerobically in minimal medium supplemented with
20 g/L glucose, and harvested 24 hours after induction with 0.1 mM
IPTG. Concentrations are given in mM. Genes on pZE13 Genes on pZA33
Succinate 4-HB BDO 0002 + 0004 + 0035 0020n - 0021n - 0036 0.336
2.91 0.230 0038 + 0035 0034 - 0036 0.814 2.81 0.126 0038 + 0035
0036 - 0034 0.741 2.57 0.114 0035 + 0032 0034 - 0036 5.01 0.538
0.154
Example III
Biosynthesis of 4-Hydroxybutanoic Acid, .gamma.-Butyrolactone and
1,4-Butanediol
[0340] This Example describes the biosynthetic production of
4-hydroxybutanoic acid, .gamma.-butyrolactone and 1,4-butanediol
using fermentation and other bioprocesses.
[0341] Methods for the integration of the 4-HB fermentation step
into a complete process for the production of purified GBL,
1,4-butanediol (BDO) and tetrahydrofuran (THF) are described below.
Since 4-HB and GBL are in equilibrium, the fermentation broth will
contain both compounds. At low pH this equilibrium is shifted to
favor GBL. Therefore, the fermentation can operate at pH 7.5 or
less, generally pH 5.5 or less. After removal of biomass, the
product stream enters into a separation step in which GBL is
removed and the remaining stream enriched in 4-HB is recycled.
Finally, GBL is distilled to remove any impurities. The process
operates in one of three ways: 1) fed-batch fermentation and batch
separation; 2) fed-batch fermentation and continuous separation; 3)
continuous fermentation and continuous separation. The first two of
these modes are shown schematically in FIG. 7. The integrated
fermentation procedures described below also are used for the BDO
producing cells of the invention for biosynthesis of BDO and
subsequent BDO family products.
[0342] Fermentation Protocol to Produce 4-HB/GBL (Batch):
[0343] The production organism is grown in a 10 L bioreactor
sparged with an N.sub.2/CO.sub.2 mixture, using 5 L broth
containing 5 g/L potassium phosphate, 2.5 g/L ammonium chloride,
0.5 g/L magnesium sulfate, and 30 g/L corn steep liquor, and an
initial glucose concentration of 20 g/L. As the cells grow and
utilize the glucose, additional 70% glucose is fed into the
bioreactor at a rate approximately balancing glucose consumption.
The temperature of the bioreactor is maintained at 30 degrees C.
Growth continues for approximately 24 hours, until 4-HB reaches a
concentration of between 20-200 g/L, with the cell density being
between 5 and 10 g/L. The pH is not controlled, and will typically
decrease to pH 3-6 by the end of the run. Upon completion of the
cultivation period, the fermenter contents are passed through a
cell separation unit (e.g., centrifuge) to remove cells and cell
debris, and the fermentation broth is transferred to a product
separations unit. Isolation of 4-HB and/or GBL would take place by
standard separations procedures employed in the art to separate
organic products from dilute aqueous solutions, such as
liquid-liquid extraction using a water immiscible organic solvent
(e.g., toluene) to provide an organic solution of 4-HB/GBL. The
resulting solution is then subjected to standard distillation
methods to remove and recycle the organic solvent and to provide
GBL (boiling point 204-205.degree. C.) which is isolated as a
purified liquid.
[0344] Fermentation Protocol to Produce 4-HB/GBL (Fully
Continuous):
[0345] The production organism is first grown up in batch mode
using the apparatus and medium composition described above, except
that the initial glucose concentration is 30-50 g/L. When glucose
is exhausted, feed medium of the same composition is supplied
continuously at a rate between 0.5 L/hr and 1 L/hr, and liquid is
withdrawn at the same rate. The 4-HB concentration in the
bioreactor remains constant at 30-40 g/L, and the cell density
remains constant between 3-5 g/L. Temperature is maintained at 30
degrees C., and the pH is maintained at 4.5 using concentrated NaOH
and HCl, as required. The bioreactor is operated continuously for
one month, with samples taken every day to assure consistency of
4-HB concentration. In continuous mode, fermenter contents are
constantly removed as new feed medium is supplied. The exit stream,
containing cells, medium, and products 4-HB and/or GBL, is then
subjected to a continuous product separations procedure, with or
without removing cells and cell debris, and would take place by
standard continuous separations methods employed in the art to
separate organic products from dilute aqueous solutions, such as
continuous liquid-liquid extraction using a water immiscible
organic solvent (e.g., toluene) to provide an organic solution of
4-HB/GBL. The resulting solution is subsequently subjected to
standard continuous distillation methods to remove and recycle the
organic solvent and to provide GBL (boiling point 204-205.degree.
C.) which is isolated as a purified liquid.
[0346] GBL Reduction Protocol:
[0347] Once GBL is isolated and purified as described above, it
will then be subjected to reduction protocols such as those well
known in the art (references cited) to produce 1,4-butanediol or
tetrahydrofuran (THF) or a mixture thereof. Heterogeneous or
homogeneous hydrogenation catalysts combined with GBL under
hydrogen pressure are well known to provide the products
1,4-butanediol or tetrahydrofuran (THF) or a mixture thereof. It is
important to note that the 4-HB/GBL product mixture that is
separated from the fermentation broth, as described above, may be
subjected directly, prior to GBL isolation and purification, to
these same reduction protocols to provide the products
1,4-butanediol or tetrahydrofuran or a mixture thereof. The
resulting products, 1,4-butanediol and THF are then isolated and
purified by procedures well known in the art.
[0348] Fermentation and Hydrogenation Protocol to Produce BDO or
THF Directly (Batch):
[0349] Cells are grown in a 10 L bioreactor sparged with an
N.sub.2/CO.sub.2 mixture, using 5 L broth containing 5 g/L
potassium phosphate, 2.5 g/L ammonium chloride, 0.5 g/L magnesium
sulfate, and 30 g/L corn steep liquor, and an initial glucose
concentration of 20 g/L. As the cells grow and utilize the glucose,
additional 70% glucose is fed into the bioreactor at a rate
approximately balancing glucose consumption. The temperature of the
bioreactor is maintained at 30 degrees C. Growth continues for
approximately 24 hours, until 4-HB reaches a concentration of
between 20-200 g/L, with the cell density being between 5 and 10
g/L. The pH is not controlled, and will typically decrease to pH
3-6 by the end of the run. Upon completion of the cultivation
period, the fermenter contents are passed through a cell separation
unit (e.g., centrifuge) to remove cells and cell debris, and the
fermentation broth is transferred to a reduction unit (e.g.,
hydrogenation vessel), where the mixture 4-HB/GBL is directly
reduced to either 1,4-butanediol or THF or a mixture thereof.
Following completion of the reduction procedure, the reactor
contents are transferred to a product separations unit. Isolation
of 1,4-butanediol and/or THF would take place by standard
separations procedures employed in the art to separate organic
products from dilute aqueous solutions, such as liquid-liquid
extraction using a water immiscible organic solvent (e.g., toluene)
to provide an organic solution of 1,4-butanediol and/or THF. The
resulting solution is then subjected to standard distillation
methods to remove and recycle the organic solvent and to provide
1,4-butanediol and/or THF which are isolated as a purified
liquids.
[0350] Fermentation and Hydrogenation Protocol to Produce BDO or
THF Directly (Fully Continuous):
[0351] The cells are first grown up in batch mode using the
apparatus and medium composition described above, except that the
initial glucose concentration is 30-50 g/L. When glucose is
exhausted, feed medium of the same composition is supplied
continuously at a rate between 0.5 L/hr and 1 L/hr, and liquid is
withdrawn at the same rate. The 4-HB concentration in the
bioreactor remains constant at 30-40 g/L, and the cell density
remains constant between 3-5 g/L. Temperature is maintained at 30
degrees C., and the pH is maintained at 4.5 using concentrated NaOH
and HCl, as required. The bioreactor is operated continuously for
one month, with samples taken every day to assure consistency of
4-HB concentration. In continuous mode, fermenter contents are
constantly removed as new feed medium is supplied. The exit stream,
containing cells, medium, and products 4-HB and/or GBL, is then
passed through a cell separation unit (e.g., centrifuge) to remove
cells and cell debris, and the fermentation broth is transferred to
a continuous reduction unit (e.g., hydrogenation vessel), where the
mixture 4-HB/GBL is directly reduced to either 1,4-butanediol or
THF or a mixture thereof. Following completion of the reduction
procedure, the reactor contents are transferred to a continuous
product separations unit. Isolation of 1,4-butanediol and/or THF
would take place by standard continuous separations procedures
employed in the art to separate organic products from dilute
aqueous solutions, such as liquid-liquid extraction using a water
immiscible organic solvent (e.g., toluene) to provide an organic
solution of 1,4-butanediol and/or THF. The resulting solution is
then subjected to standard continuous distillation methods to
remove and recycle the organic solvent and to provide
1,4-butanediol and/or THF which are isolated as a purified
liquids.
[0352] Fermentation Protocol to Produce BDO Directly (Batch):
[0353] The production organism is grown in a 10 L bioreactor
sparged with an N.sub.2/CO.sub.2 mixture, using 5 L broth
containing 5 g/L potassium phosphate, 2.5 g/L ammonium chloride,
0.5 g/L magnesium sulfate, and 30 g/L corn steep liquor, and an
initial glucose concentration of 20 g/L. As the cells grow and
utilize the glucose, additional 70% glucose is fed into the
bioreactor at a rate approximately balancing glucose consumption.
The temperature of the bioreactor is maintained at 30 degrees C.
Growth continues for approximately 24 hours, until BDO reaches a
concentration of between 20-200 g/L, with the cell density
generally being between 5 and 10 g/L. Upon completion of the
cultivation period, the fermenter contents are passed through a
cell separation unit (e.g., centrifuge) to remove cells and cell
debris, and the fermentation broth is transferred to a product
separations unit. Isolation of BDO would take place by standard
separations procedures employed in the art to separate organic
products from dilute aqueous solutions, such as liquid-liquid
extraction using a water immiscible organic solvent (e.g., toluene)
to provide an organic solution of BDO. The resulting solution is
then subjected to standard distillation methods to remove and
recycle the organic solvent and to provide BDO (boiling point
228-229.degree. C.) which is isolated as a purified liquid.
[0354] Fermentation Protocol to Produce BDO Directly (Fully
Continuous):
[0355] The production organism is first grown up in batch mode
using the apparatus and medium composition described above, except
that the initial glucose concentration is 30-50 g/L. When glucose
is exhausted, feed medium of the same composition is supplied
continuously at a rate between 0.5 L/hr and 1 L/hr, and liquid is
withdrawn at the same rate. The BDO concentration in the bioreactor
remains constant at 30-40 g/L, and the cell density remains
constant between 3-5 g/L. Temperature is maintained at 30 degrees
C., and the pH is maintained at 4.5 using concentrated NaOH and
HCl, as required. The bioreactor is operated continuously for one
month, with samples taken every day to assure consistency of BDO
concentration. In continuous mode, fermenter contents are
constantly removed as new feed medium is supplied. The exit stream,
containing cells, medium, and the product BDO, is then subjected to
a continuous product separations procedure, with or without
removing cells and cell debris, and would take place by standard
continuous separations methods employed in the art to separate
organic products from dilute aqueous solutions, such as continuous
liquid-liquid extraction using a water immiscible organic solvent
(e.g., toluene) to provide an organic solution of BDO. The
resulting solution is subsequently subjected to standard continuous
distillation methods to remove and recycle the organic solvent and
to provide BDO (boiling point 228-229.degree. C.) which is isolated
as a purified liquid (mpt 20.degree. C.).
Example IV
Exemplary BDO Pathways
[0356] This example describes exemplary enzymes and corresponding
genes for 1,4-butandiol (BDO) synthetic pathways.
[0357] Exemplary BDO synthetic pathways are shown in FIGS. 8-13.
The pathways depicted in FIGS. 8-13 are from common central
metabolic intermediates to 1,4-butanediol. All transformations
depicted in FIGS. 8-13 fall into the 18 general categories of
transformations shown in Table 14. Below is described a number of
biochemically characterized candidate genes in each category.
Specifically listed are genes that can be applied to catalyze the
appropriate transformations in FIGS. 9-13 when cloned and expressed
in a host organism. The top three exemplary genes for each of the
key steps in FIGS. 9-13 are provided in Tables 15-23 (see below).
Exemplary genes were provided for the pathways depicted in FIG. 8
are described herein.
TABLE-US-00015 TABLE 14 Enzyme types required to convert common
central metabolic intermediates into 1,4-butanediol. The first
three digits of each label correspond to the first three Enzyme
Commission number digits which denote the general type of
transformation independent of substrate specificity. Label Function
1.1.1.a Oxidoreductase (ketone to hydroxyl or aldehyde to alcohol)
1.1.1.c Oxidoreductase (2 step, acyl-CoA to alcohol) 1.2.1.b
Oxidoreductase (acyl-CoA to aldehyde) 1.2.1.c Oxidoreductase (2-oxo
acid to acyl-CoA, decarboxylation) 1.2.1.d Oxidoreductase
(phosphorylating/dephosphorylating) 1.3.1.a Oxidoreductase
operating on CH--CH donors 1.4.1.a Oxidoreductase operating on
amino acids 2.3.1.a Acyltransferase (transferring phosphate group)
2.6.1.a Aminotransferase 2.7.2.a Phosphotransferase, carboxyl group
acceptor 2.8.3.a Coenzyme-A transferase 3.1.2.a Thiolester
hydrolase (CoA specific) 4.1.1.a Carboxy-lyase 4.2.1.a Hydro-lyase
4.3.1.a Ammonia-lyase 5.3.3.a Isomerase 5.4.3.a Aminomutase 6.2.1.a
Acid-thiol ligase
1.1.1.a--Oxidoreductase (Aldehyde to Alcohol or Ketone to
Hydroxyl)
[0358] Aldehyde to alcohol. Exemplary genes encoding enzymes that
catalyze the conversion of an aldehyde to alcohol, that is, alcohol
dehydrogenase or equivalently aldehyde reductase, include alrA
encoding a medium-chain alcohol dehydrogenase for C2-C14 (Tani et
al. Appl. Environ. Microbiol. 66:5231-5235 (2000)), ADH2 from
Saccharomyces cerevisiae (Atsumi et al. Nature 451:86-89 (2008)),
yqhD from E. coli which has preference for molecules longer than
C(3) (Sulzenbacher et al. Journal of Molecular Biology 342:489-502
(2004)), and bdh I and bdh II from C. acetobutylicum which converts
butyryaldehyde into butanol (Walter et al. Journal of Bacteriology
174:7149-7158 (1992)). The protein sequences for each of these
exemplary gene products, if available, can be found using the
following GenBank accession numbers:
TABLE-US-00016 Gene Accession No. GI No. Organism alrA BAB12273.1
9967138 Acinetobacter sp. Strain M-1 ADH2 NP_014032.1 6323961
Saccharymyces cerevisiae yqhD NP_417484.1 16130909 Escherichia coli
bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II
NP_349891.1 15896542 Clostridium acetobutylicum
[0359] Enzymes exhibiting 4-hydroxybutyrate dehydrogenase activity
(EC 1.1.1.61) also fall into this category. Such enzymes have been
characterized in Ralstonia eutropha (Bravo et al. J. Forensic Sci.
49:379-387 (2004), Clostridium kluyveri (Wolff et al. Protein Expr.
Purif. 6:206-212 (1995)) and Arabidopsis thaliana (Breitkreuz et
al. J. Biol. Chem. 278:41552-41556 (2003)).
TABLE-US-00017 Gene Accession No. GI No. Organism 4hbd YP_726053.1
113867564 Ralstonia eutropha H16 4hbd L21902.1 146348486
Clostridium kluyveri DSM 555 4hbd Q94B07 75249805 Arabidopsis
thaliana
[0360] Another exemplary enzyme is 3-hydroxyisobutyrate
dehydrogenase which catalyzes the reversible oxidation of
3-hydroxyisobutyrate to methylmalonate semialdehyde. This enzyme
participates in valine, leucine and isoleucine degradation and has
been identified in bacteria, eukaryotes, and mammals. The enzyme
encoded by P84067 from Thermus thermophilus HB8 has been
structurally characterized (Lokanath et al. J Mol Biol 352:905-17
(2005)). The reversibility of the human 3-hydroxyisobutyrate
dehydrogenase was demonstrated using isotopically-labeled substrate
(Manning et al. Biochem J 231:481-484 (1985)). Additional genes
encoding this enzyme include 3hidh in Homo sapiens (Hawes et al.
Methods Enzymol. 324:218-228 (2000)) and Oryctolagus cuniculus
(Chowdhury et al. Biosci. Biotechnol Biochem. 60:2043-2047 (1996);
Hawes et al. Methods Enzymol. 324:218-228 (2000)), mmsb in
Pseudomonas aeruginosa, and dhat in Pseudomonas putida (Aberhart et
al. J Chem. Soc. [Perkin 1] 6:1404-1406 (1979); Chowdhury et al.
Biosci. Biotechnol Biochem. 67:438-441 (2003); Chowdhury et al.
Biosci. Biotechnol Biochem. 60:2043-2047 (1996)).
TABLE-US-00018 Gene Accession No. GI No. Organism P84067 P84067
75345323 Thermus thermophilus mmsb P28811.1 127211 Pseudomonas
aeruginosa dhat Q59477.1 2842618 Pseudomonas putida 3hidh P31937.2
12643395 Homo sapiens 3hidh P32185.1 416872 Oryctolagus
cuniculus
[0361] Several 3-hydroxyisobutyrate dehydrogenase enzymes have also
been shown to convert malonic semialdehyde to 3-hydroxyproprionic
acid (3-HP). Three gene candidates exhibiting this activity are
mmsB from Pseudomonas aeruginosa PAO1(62), mmsB from Pseudomonas
putida KT2440 (Liao et al., US Publication 2005/0221466) and mmsB
from Pseudomonas putida E23 (Chowdhury et al., Biosci. Biotechnol.
Biochem. 60:2043-2047 (1996)). An enzyme with 3-hydroxybutyrate
dehydrogenase activity in Alcaligenes faecalis M3A has also been
identified (Gokam et al., U.S. Pat. No. 7,393,676; Liao et al., US
Publication No. 2005/0221466). Additional gene candidates from
other organisms including Rhodobacter spaeroides can be inferred by
sequence similarity.
TABLE-US-00019 Gene Accession No. GI No. Organism mmsB AAA25892.1
151363 Pseudomonas aeruginosa mmsB NP_252259.1 15598765 Pseudomonas
aeruginosa PAO1 mmsB NP_746775.1 26991350 Pseudomonas putida KT2440
mmsB JC7926 60729613 Pseudomonas putida E23 orfB1 AAL26884 16588720
Rhodobacter spaeroides
[0362] The conversion of malonic semialdehyde to 3-HP can also be
accomplished by two other enzymes: NADH-dependent
3-hydroxypropionate dehydrogenase and NADPH-dependent malonate
semialdehyde reductase. An NADH-dependent 3-hydroxypropionate
dehydrogenase is thought to participate in beta-alanine
biosynthesis pathways from propionate in bacteria and plants
(Rathinasabapathi, B. Journal of Plant Pathology 159:671-674
(2002); Stadtman, E. R. J. Am. Chem. Soc. 77:5765-5766 (1955)).
This enzyme has not been associated with a gene in any organism to
date. NADPH-dependent malonate semialdehyde reductase catalyzes the
reverse reaction in autotrophic CO.sub.2-fixing bacteria. Although
the enzyme activity has been detected in Metallosphaera sedula, the
identity of the gene is not known (Alber et al. J. Bacteriol.
188:8551-8559 (2006)).
[0363] Ketone to Hydroxyl.
[0364] There exist several exemplary alcohol dehydrogenases that
convert a ketone to a hydroxyl functional group. Two such enzymes
from E. coli are encoded by malate dehydrogenase (mdh) and lactate
dehydrogenase (ldhA). In addition, lactate dehydrogenase from
Ralstonia eutropha has been shown to demonstrate high activities on
substrates of various chain lengths such as lactate, 2-oxobutyrate,
2-oxopentanoate and 2-oxoglutarate (Steinbuchel and. Schlegel, Eur.
J. Biochem. 130:329-334 (1983)). Conversion of alpha-ketoadipate
into alpha-hydroxyadipate can be catalyzed by 2-ketoadipate
reductase, an enzyme reported to be found in rat and in human
placenta (Suda et al. Arch. Biochem. Biophys. 176:610-620 (1976);
Suda et al. Biochem. Biophys. Res. Commun. 77:586-591 (1977)). An
additional candidate for this step is the mitochondrial
3-hydroxybutyrate dehydrogenase (bdh) from the human heart which
has been cloned and characterized (Marks et al. J. Biol. Chem.
267:15459-15463 (1992)). This enzyme is a dehydrogenase that
operates on a 3-hydroxyacid. Another exemplary alcohol
dehydrogenase converts acetone to isopropanol as was shown in C.
beijerinckii (Ismaiel et al. J. Bacteriol. 175:5097-5105 (1993))
and T. brockii (Lamed et al. Biochem. J. 195:183-190 (1981); Peretz
and Burstein Biochemistry 28:6549-6555 (1989)).
TABLE-US-00020 Gene Accession No. GI No. Organism mdh AAC76268.1
1789632 Escherichia coli ldhA NP_415898.1 16129341 Escherichia coli
ldh YP_725182.1 113866693 Ralstonia eutropha bdh AAA58352.1 177198
Homo sapiens adh AAA23199.2 60592974 Clostridium beijerinckii NRRL
B593 adh P14941.1 113443 Thermoanaerobacter brockii HTD4
[0365] Exemplary 3-hydroxyacyl dehydrogenases which convert
acetoacetyl-CoA to 3-hydroxybutyryl-CoA include hbd from C.
acetobutylicum (Boynton et al. Journal of Bacteriology
178:3015-3024 (1996)), hbd from C. beijerinckii (Colby et al. Appl
Environ. Microbiol 58:3297-3302 (1992)), and a number of similar
enzymes from Metallosphaera sedula (Berg et al. Archaea. Science
318:1782-1786 (2007)).
TABLE-US-00021 Gene Accession No. GI No. Organism hbd NP_349314.1
15895965 Clostridium acetobutylicum hbd AAM14586.1 20162442
Clostridium beijerinckii Msed_1423 YP_001191505 146304189
Metallosphaera sedula Msed_0399 YP_001190500 146303184
Metallosphaera sedula Msed_0389 YP_001190490 146303174
Metallosphaera sedula Msed_1993 YP_001192057 146304741
Metallosphaera sedula
1.1.1.c--Oxidoredutase (2 Step, Acyl-CoA to Alcohol)
[0366] Exemplary 2-step oxidoreductases that convert an acyl-CoA to
alcohol include those that transform substrates such as acetyl-CoA
to ethanol (for example, adhE from E. coli (Kessler et al. FEBS.
Lett. 281:59-63 (1991)) and butyryl-CoA to butanol (for example,
adhE2 from C. acetobutylicum (Fontaine et al. J. Bacteriol.
184:821-830 (2002)). In addition to reducing acetyl-CoA to ethanol,
the enzyme encoded by adhE in Leuconostoc mesenteroides has been
shown to oxide the branched chain compound isobutyraldehyde to
isobutyryl-CoA (Kazahaya et al. J. Gen. Appl. Microbiol. 18:43-55
(1972); Koo et al. Biotechnol Lett. 27:505-510 (2005)).
TABLE-US-00022 Gene Accession No. GI No. Organism adhE NP_415757.1
16129202 Escherichia coli adhE2 AAK09379.1 12958626 Clostridium
acetobutylicum adhE AAV66076.1 55818563 Leuconostoc
mesenteroides
[0367] Another exemplary enzyme can convert malonyl-CoA to 3-HP. An
NADPH-dependent enzyme with this activity has characterized in
Chloroflexus aurantiacus where it participates in the
3-hydroxypropionate cycle (Hugler et al., J. Bacteriol.
184:2404-2410 (2002); Strauss and Fuchs, Eur. J. Biochem.
215:633-643 (1993)). This enzyme, with a mass of 300 kDa, is highly
substrate-specific and shows little sequence similarity to other
known oxidoreductases (Hugler et al., J. Bacteriol. 184:2404-2410
(2002)). No enzymes in other organisms have been shown to catalyze
this specific reaction; however there is bioinformatic evidence
that other organisms may have similar pathways (Klatt et al.,
Environ. Microbiol. 9:2067-2078 (2007)). Enzyme candidates in other
organisms including Roseiflexus castenholzii, Erythrobacter sp.
NAP1 and marine gamma proteobacterium HTCC2080 can be inferred by
sequence similarity.
TABLE-US-00023 Gene Accession No. GI No. Organism mcr AAS20429.1
42561982 Chloroflexus aurantiacus Rcas_2929 YP_001433009.1
156742880 Roseiflexus castenholzii NAP1_02720 ZP_01039179.1
85708113 Erythrobacter sp. NAP1 MGP2080_00535 ZP_01626393.1
119504313 Marine gamma proteobacterium HTCC2080
[0368] Longer chain acyl-CoA molecules can be reduced by enzymes
such as the jojoba (Simmondsia chinensis) FAR which encodes an
alcohol-forming fatty acyl-CoA reductase. Its overexpression in E.
coli resulted in FAR activity and the accumulation of fatty alcohol
(Metz et al. Plant Physiology 122:635-644) 2000)).
TABLE-US-00024 Gene Accession No. GI No. Organism FAR AAD38039.1
5020215 Simmondsia chinensis
1.2.1.b--Oxidoreductase (Acyl-CoA to Aldehyde)
[0369] Several acyl-CoA dehydrogenases are capable of reducing an
acyl-CoA to its corresponding aldehyde. Exemplary genes that encode
such enzymes include the Acinetobacter calcoaceticus acr1 encoding
a fatty acyl-CoA reductase (Reiser and Somerville, J. Bacteriology
179:2969-2975 (1997)), the Acinetobacter sp. M-1 fatty acyl-CoA
reductase (Ishige et al. Appl. Environ. Microbiol. 68:1192-1195
(2002)), and a CoA- and NADP-dependent succinate semialdehyde
dehydrogenase encoded by the sucD gene in Clostridium kluyveri
(Sohling and Gottschalk J Bacteriol 178:871-80 (1996); Sohling and
Gottschalk J Bacteriol. 178:871-880 (1996)). SucD of P. gingivalis
is another succinate semialdehyde dehydrogenase (Takahashi et al.
J. Bacteriol. 182:4704-4710 (2000)). The enzyme acylating
acetaldehyde dehydrogenase in Pseudomonas sp, encoded by bphG, is
yet another as it has been demonstrated to oxidize and acylate
acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde and
formaldehyde (Powlowski et al. J Bacteriol. 175:377-385
(1993)).
TABLE-US-00025 Gene Accession No. GI No. Organism acr1 YP_047869.1
50086359 Acinetobacter calcoaceticus acr1 AAC45217 1684886
Acinetobacter baylyi acr1 BAB85476.1 18857901 Acinetobacter sp.
Strain M-1 sucD P38947.1 730847 Clostridium kluyveri sucD
NP_904963.1 34540484 Porphyromonas gingivalis bphG BAA03892.1
425213 Pseudomonas sp
[0370] An additional enzyme type that converts an acyl-CoA to its
corresponding aldehyde is malonyl-CoA reductase which transforms
malonyl-CoA to malonic semialdehyde. Malonyl-CoA reductase is a key
enzyme in autotrophic carbon fixation via the 3-hydroxypropionate
cycle in thermoacidophilic archael bacteria (Berg et al. Science
318:1782-1786 (2007); Thauer, R. K. Science 318:1732-1733 (2007)).
The enzyme utilizes NADPH as a cofactor and has been characterized
in Metallosphaera and Sulfolobus spp (Alber et al. J. Bacteriol.
188:8551-8559 (2006); Hugler et al. J. Bacteriol. 184:2404-2410
(2002)). The enzyme is encoded by Msed_0709 in Metallosphaera
sedula (Alber et al. J. Bacteriol. 188:8551-8559 (2006); Berg et
al. Science 318:1782-1786 (2007)). A gene encoding a malonyl-CoA
reductase from Sulfolobus tokodaii was cloned and heterologously
expressed in E. coli (Alber et al. J. Bacteriol. 188:8551-8559
(2006)). Although the aldehyde dehydrogenase functionality of these
enzymes is similar to the bifunctional dehydrogenase from
Chloroflexus aurantiacus, there is little sequence similarity. Both
malonyl-CoA reductase enzyme candidates have high sequence
similarity to aspartate-semialdehyde dehydrogenase, an enzyme
catalyzing the reduction and concurrent dephosphorylation of
aspartyl-4-phosphate to aspartate semialdehyde. Additional gene
candidates can be found by sequence homology to proteins in other
organisms including Sulfolobus solfataricus and Sulfolobus
acidocaldarius.
TABLE-US-00026 Gene Accession No. GI No. Organism Msed_0709
YP_001190808.1 146303492 Metallosphaera sedula mcr NP_378167.1
15922498 Sulfolobus tokodaii asd-2 NP_343563.1 15898958 Sulfolobus
solfataricus Saci_2370 YP_256941.1 70608071 Sulfolobus
acidocaldarius
1.2.1.c--Oxidoreductase (2-Oxo Acid to Acyl-CoA,
Decarboxylation)
[0371] Enzymes in this family include 1) branched-chain 2-keto-acid
dehydrogenase, 2) alpha-ketoglutarate dehydrogenase, and 3) the
pyruvate dehydrogenase multienzyme complex (PDHC). These enzymes
are multi-enzyme complexes that catalyze a series of partial
reactions which result in acylating oxidative decarboxylation of
2-keto-acids. Each of the 2-keto-acid dehydrogenase complexes
occupies key positions in intermediary metabolism, and enzyme
activity is typically tightly regulated (Fries et al. Biochemistry
42:6996-7002 (2003)). The enzymes share a complex but common
structure composed of multiple copies of three catalytic
components: alpha-ketoacid decarboxylase (E1), dihydrolipoamide
acyltransferase (E2) and dihydrolipoamide dehydrogenase (E3). The
E3 component is shared among all 2-keto-acid dehydrogenase
complexes in an organism, while the E1 and E2 components are
encoded by different genes. The enzyme components are present in
numerous copies in the complex and utilize multiple cofactors to
catalyze a directed sequence of reactions via substrate channeling.
The overall size of these dehydrogenase complexes is very large,
with molecular masses between 4 and 10 million Da (that is, larger
than a ribosome).
[0372] Activity of enzymes in the 2-keto-acid dehydrogenase family
is normally low or limited under anaerobic conditions in E. coli.
Increased production of NADH (or NADPH) could lead to a
redox-imbalance, and NADH itself serves as an inhibitor to enzyme
function. Engineering efforts have increased the anaerobic activity
of the E. coli pyruvate dehydrogenase complex (Kim et al. Appl.
Environ. Microbiol. 73:1766-1771 (2007); Kim et al. J. Bacteriol.
190:3851-3858) 2008); Zhou et al. Biotechnol. Lett. 30:335-342
(2008)). For example, the inhibitory effect of NADH can be overcome
by engineering an H322Y mutation in the E3 component (Kim et al. J.
Bacteriol. 190:3851-3858 (2008)). Structural studies of individual
components and how they work together in complex provide insight
into the catalytic mechanisms and architecture of enzymes in this
family (Aevarsson et al. Nat. Struct. Biol. 6:785-792 (1999); Zhou
et al. Proc. Natl. Acad. Sci. U.S.A. 98:14802-14807 (2001)). The
substrate specificity of the dehydrogenase complexes varies in
different organisms, but generally branched-chain keto-acid
dehydrogenases have the broadest substrate range.
[0373] Alpha-ketoglutarate dehydrogenase (AKGD) converts
alpha-ketoglutarate to succinyl-CoA and is the primary site of
control of metabolic flux through the TCA cycle (Hansford, R. G.
Curr. Top. Bioenerg. 10:217-278 (1980)). Encoded by genes sucA,
sucB and lpd in E. coli, AKGD gene expression is downregulated
under anaerobic conditions and during growth on glucose (Park et
al. Mol. Microbiol. 15:473-482 (1995)). Although the substrate
range of AKGD is narrow, structural studies of the catalytic core
of the E2 component pinpoint specific residues responsible for
substrate specificity (Knapp et al. J. Mol. Biol. 280:655-668
(1998)). The Bacillus subtilis AKGD, encoded by odhAB (E1 and E2)
and pdhD (E3, shared domain), is regulated at the transcriptional
level and is dependent on the carbon source and growth phase of the
organism (Resnekov et al. Mol. Gen. Genet. 234:285-296 (1992)). In
yeast, the LPD1 gene encoding the E3 component is regulated at the
transcriptional level by glucose (Roy and Dawes J. Gen. Microbiol.
133:925-933 (1987)). The E1 component, encoded by KGD1, is also
regulated by glucose and activated by the products of HAP2 and HAP3
(Repetto and Tzagoloff Mol. Cell Biol. 9:2695-2705 (1989)). The
AKGD enzyme complex, inhibited by products NADH and succinyl-CoA,
is well-studied in mammalian systems, as impaired function of has
been linked to several neurological diseases (Tretter and dam-Vizi
Philos. Trans. R. Soc. Lond B Biol. Sci. 360:2335-2345 (2005)).
TABLE-US-00027 Gene Accession No. GI No. Organism sucA NP_415254.1
16128701 Escherichia coli str. K12 substr. MG1655 sucB NP_415255.1
16128702 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1
16128109 Escherichia coli str. K12 substr. MG1655 odhA P23129.2
51704265 Bacillus subtilis odhB P16263.1 129041 Bacillus subtilis
pdhD P21880.1 118672 Bacillus subtilis KGD1 NP_012141.1 6322066
Saccharomyces cerevisiae KGD2 NP_010432.1 6320352 Saccharomyces
cerevisiae LPD1 NP_116635.1 14318501 Saccharomyces cerevisiae
[0374] Branched-chain 2-keto-acid dehydrogenase complex (BCKAD),
also known as 2-oxoisovalerate dehydrogenase, participates in
branched-chain amino acid degradation pathways, converting 2-keto
acids derivatives of valine, leucine and isoleucine to their
acyl-CoA derivatives and CO.sub.2. The complex has been studied in
many organisms including Bacillus subtilis (Wang et al. Eur. J.
Biochem. 213:1091-1099 (1993)), Rattus norvegicus (Namba et al. J.
Biol. Chem. 244:4437-4447 (1969)) and Pseudomonas putida (Sokatch
J. Bacteriol. 148:647-652 (1981)). In Bacillus subtilis the enzyme
is encoded by genes pdhD (E3 component), bfmBB (E2 component),
bfmBAA and bfmBAB (E1 component) (Wang et al. Eur. J. Biochem.
213:1091-1099 (1993)). In mammals, the complex is regulated by
phosphorylation by specific phosphatases and protein kinases. The
complex has been studied in rat hepatocites (Chicco et al. J. Biol.
Chem. 269:19427-19434 (1994)) and is encoded by genes Bckdha (E1
alpha), Bckdhb (E1 beta), Dbt (E2), and Dld (E3). The E1 and E3
components of the Pseudomonas putida BCKAD complex have been
crystallized (Aevarsson et al. Nat. Struct. Biol. 6:785-792 (1999);
Mattevi Science 255:1544-1550 (1992)) and the enzyme complex has
been studied (Sokatch et al. J. Bacteriol. 148:647-652 (1981)).
Transcription of the P. putida BCKAD genes is activated by the gene
product of bkdR (Hester et al. Eur. J. Biochem. 233:828-836
(1995)). In some organisms including Rattus norvegicus (Paxton et
al. Biochem. J. 234:295-303 (1986)) and Saccharomyces cerevisiae
(Sinclair et al. Biochem. Mol. Biol. Int. 31:911-922 (1993)), this
complex has been shown to have a broad substrate range that
includes linear oxo-acids such as 2-oxobutanoate and
alpha-ketoglutarate, in addition to the branched-chain amino acid
precursors. The active site of the bovine BCKAD was engineered to
favor alternate substrate acetyl-CoA (Meng and Chuang, Biochemistry
33:12879-12885 (1994)).
TABLE-US-00028 Gene Accession No. GI No. Organism bfmBB NP_390283.1
16079459 Bacillus subtilis bfmBAA NP_390285.1 16079461 Bacillus
subtilis bfmBAB NP_390284.1 16079460 Bacillus subtilis pdhD
P21880.1 118672 Bacillus subtilis lpdV P09063.1 118677 Pseudomonas
putida bkdB P09062.1 129044 Pseudomonas putida bkdA1 NP_746515.1
26991090 Pseudomonas putida bkdA2 NP_746516.1 26991091 Pseudomonas
putida Bckdha NP_036914.1 77736548 Rattus norvegicus Bckdhb
NP_062140.1 158749538 Rattus norvegicus Dbt NP_445764.1 158749632
Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus
[0375] The pyruvate dehydrogenase complex, catalyzing the
conversion of pyruvate to acetyl-CoA, has also been extensively
studied. In the E. coli enzyme, specific residues in the E1
component are responsible for substrate specificity (Bisswanger, H.
J Biol Chem. 256:815-822 (1981); Bremer, J. Eur. J Biochem.
8:535-540 (1969); Gong et al. J Biol Chem. 275:13645-13653 (2000)).
As mentioned previously, enzyme engineering efforts have improved
the E. coli PDH enzyme activity under anaerobic conditions (Kim et
al. Appl. Environ. Microbiol. 73:1766-1771 (2007); Kim J.
Bacteriol. 190:3851-3858 (2008); Zhou et al. Biotechnol. Lett.
30:335-342 (2008)). In contrast to the E. coli PDH, the B. subtilis
complex is active and required for growth under anaerobic
conditions (Nakano J. Bacteriol. 179:6749-6755 (1997)). The
Klebsiella pneumoniae PDH, characterized during growth on glycerol,
is also active under anaerobic conditions (Menzel et al. J.
Biotechnol. 56:135-142 (1997)). Crystal structures of the enzyme
complex from bovine kidney (Zhou et al. Proc. Natl. Acad. Sci.
U.S.A. 98:14802-14807 (2001)) and the E2 catalytic domain from
Azotobacter vinelandii are available (Mattevi et al. Science
255:1544-1550 (1992)). Some mammalian PDH enzymes complexes can
react on alternate substrates such as 2-oxobutanoate, although
comparative kinetics of Rattus norvegicus PDH and BCKAD indicate
that BCKAD has higher activity on 2-oxobutanoate as a substrate
(Paxton et al. Biochem. J. 234:295-303 (1986)).
TABLE-US-00029 Gene Accession No. GI No. Organism aceE NP_414656.1
16128107 Escherichia coli str. K12 substr. MG1655 aceF NP_414657.1
16128108 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1
16128109 Escherichia coli str. K12 substr. MG1655 pdhA P21881.1
3123238 Bacillus subtilis pdhB P21882.1 129068 Bacillus subtilis
pdhC P21883.2 129054 Bacillus subtilis pdhD P21880.1 118672
Bacillus subtilis aceE YP_001333808.1 152968699 Klebsiella
pneumonia MGH78578 aceF YP_001333809.1 152968700 Klebsiella
pneumonia MGH78578 lpdA YP_001333810.1 152968701 Klebsiella
pneumonia MGH78578 Pdha1 NP_001004072.2 124430510 Rattus norvegicus
Pdha2 NP_446446.1 16758900 Rattus norvegicus Dlat NP_112287.1
78365255 Rattus norvegicus Dld NP_955417.1 40786469 Rattus
norvegicus
[0376] As an alternative to the large multienzyme 2-keto-acid
dehydrogenase complexes described above, some anaerobic organisms
utilize enzymes in the 2-ketoacid oxidoreductase family (OFOR) to
catalyze acylating oxidative decarboxylation of 2-keto-acids.
Unlike the dehydrogenase complexes, these enzymes contain
iron-sulfur clusters, utilize different cofactors, and use
ferredoxin or flavodixin as electron acceptors in lieu of NAD(P)H.
While most enzymes in this family are specific to pyruvate as a
substrate (POR) some 2-keto-acid:ferredoxin oxidoreductases have
been shown to accept a broad range of 2-ketoacids as substrates
including alpha-ketoglutarate and 2-oxobutanoate (Fukuda and Wakagi
Biochim. Biophys. Acta 1597:74-80 (2002); Zhang et al. J. Biochem.
120:587-599 (1996)). One such enzyme is the OFOR from the
thermoacidophilic archaeon Sulfolobus tokodaii 7, which contains an
alpha and beta subunit encoded by gene ST2300 (Fukuda and Wakagi
Biochim. Biophys. Acta 1597:74-80 (2002); Zhang et al. J. Biochem.
120:587-599 (1996)). A plasmid-based expression system has been
developed for efficiently expressing this protein in E. coli
(Fukuda et al. Eur. J. Biochem. 268:5639-5646 (2001)) and residues
involved in substrate specificity were determined (Fukuda and
Wakagi Biochim. Biophys. Acta 1597:74-80 (2002)). Two OFORs from
Aeropyrum pernix str. K1 have also been recently cloned into E.
coli, characterized, and found to react with a broad range of
2-oxoacids (Nishizawa et al. FEBS Lett. 579:2319-2322 (2005)). The
gene sequences of these OFOR candidates are available, although
they do not have GenBank identifiers assigned to date. There is
bioinformatic evidence that similar enzymes are present in all
archaea, some anaerobic bacteria and amitochondrial eukarya (Fukuda
and Wakagi Biochim. Biophys. Acta 1597:74-80 (2005)). This class of
enzyme is also interesting from an energetic standpoint, as reduced
ferredoxin could be used to generate NADH by ferredoxin-NAD
reductase (Petitdemange et al. Biochim. Biophys. Acta 421:334-337
(1976)). Also, since most of the enzymes are designed to operate
under anaerobic conditions, less enzyme engineering may be required
relative to enzymes in the 2-keto-acid dehydrogenase complex family
for activity in an anaerobic environment.
TABLE-US-00030 Gene Accession No. GI No. Organism ST2300
NP_378302.1 15922633 Sulfolobus tokodaii 7
1.2.1.d--Oxidoreductase (Phosphorylating/Dephosphorylating)
[0377] Exemplary enzymes in this class include glyceraldehyde
3-phosphate dehydrogenase which converts glyceraldehyde-3-phosphate
into D-glycerate 1,3-bisphosphate (for example, E. coli gapA
(Branlant and Branlant Eur. J. Biochem. 150:61-66(1985)),
aspartate-semialdehyde dehydrogenase which converts
L-aspartate-4-semialdehyde into L-4-aspartyl-phosphate (for
example, E. coli asd (Biellmann et al. Eur. J. Biochem. 104:53-58
(1980)), N-acetyl-gamma-glutamyl-phosphate reductase which converts
N-acetyl-L-glutamate-5-semialdehyde into
N-acetyl-L-glutamyl-5-phosphate (for example, E. coli argC (Parsot
et al. Gene 68:275-283 (1988)), and glutamate-5-semialdehyde
dehydrogenase which converts L-glutamate-5-semialdehyde into
L-glutamyl-5-phosphate (for example, E. coli proA (Smith et al. J.
Bacteriol. 157:545-551 (1984)).
TABLE-US-00031 Gene Accession No. GI No. Organism gapA P0A9B2.2
71159358 Escherichia coli asd NP_417891.1 16131307 Escherichia coli
argC NP_418393.1 16131796 Escherichia coli proA NP_414778.1
16128229 Escherichia coli
1.3.1.a--Oxidoreductase Operating on CH--CH Donors
[0378] An exemplary enoyl-CoA reductase is the gene product of bcd
from C. acetobutylicum (Atsumi et al. Metab Eng (2007); Boynton et
al. Journal of Bacteriology 178:3015-3024 (1996), which naturally
catalyzes the reduction of crotonyl-CoA to butyryl-CoA. Activity of
this enzyme can be enhanced by expressing bcd in conjunction with
expression of the C. acetobutylicum etfAB genes, which encode an
electron transfer flavoprotein. An additional candidate for the
enoyl-CoA reductase step is the mitochondrial enoyl-CoA reductase
from E. gracilis (Hoffmeister et al. Journal of Biological
Chemistry 280:4329-4338 (2005)). A construct derived from this
sequence following the removal of its mitochondrial targeting
leader sequence was cloned in E. coli resulting in an active enzyme
(Hoffmeister et al., supra, (2005)). This approach is well known to
those skilled in the art of expressing eukaryotic genes,
particularly those with leader sequences that may target the gene
product to a specific intracellular compartment, in prokaryotic
organisms. A close homolog of this gene, TDE0597, from the
prokaryote Treponema denticola represents a third enoyl-CoA
reductase which has been cloned and expressed in E. coli (Tucci and
Martin FEBS Letters 581:1561-1566 (2007)).
TABLE-US-00032 Gene Accession No. GI No. Organism bcd NP_349317.1
15895968 Clostridium acetobutylicum etfA NP_349315.1 15895966
Clostridium acetobutylicum etfB NP_349316.1 15895967 Clostridium
acetobutylicum TER Q5EU90.1 62287512 Euglena gracilis TDE0597
NP_971211.1 42526113 Treponema denticola
[0379] Exemplary 2-enoate reductase (EC 1.3.1.31) enzymes are known
to catalyze the NADH-dependent reduction of a wide variety of
.alpha., .beta.-unsaturated carboxylic acids and aldehydes (Rohdich
et al. J. Biol. Chem. 276:5779-5787 (2001)). 2-Enoate reductase is
encoded by enr in several species of Clostridia (Giesel and Simon
Arch Microbiol. 135(1): p. 51-57 (2001) including C. tyrobutyricum,
and C. thermoaceticum (now called Moorella thermoaceticum) (Rohdich
et al., supra, (2001)). In the recently published genome sequence
of C. kluyveri, 9 coding sequences for enoate reductases have been
reported, out of which one has been characterized (Seedorf et al.
Proc Natl Acad Sci U.S.A 105(6):2128-33 (2008)). The enr genes from
both C. tyrobutyricum and C. thermoaceticum have been cloned and
sequenced and show 59% identity to each other. The former gene is
also found to have approximately 75% similarity to the
characterized gene in C. kluyveri (Giesel and Simon Arch Microbiol
135(1):51-57 (1983)). It has been reported based on these sequence
results that enr is very similar to the dienoyl CoA reductase in E.
coli (fadH) (163 Rohdich et al., supra (2001)). The C.
thermoaceticum enr gene has also been expressed in an enzymatically
active form in E. coli (163 Rohdich et al., supra (2001)).
TABLE-US-00033 Gene Accession No. GI No. Organism fadH NP_417552.1
16130976 Escherichia coli enr ACA54153.1 169405742 Clostridium
botulinum A3 str enr CAA71086.1 2765041 Clostridium tyrobutyricum
enr CAA76083.1 3402834 Clostridium kluyveri enr YP_430895.1
83590886 Moorella thermoacetica
1.4.1.a--Oxidoreductase Operating on Amino Acids
[0380] Most oxidoreductases operating on amino acids catalyze the
oxidative deamination of alpha-amino acids with NAD+ or NADP+ as
acceptor. Exemplary oxidoreductases operating on amino acids
include glutamate dehydrogenase (deaminating), encoded by gdhA,
leucine dehydrogenase (deaminating), encoded by ldh, and aspartate
dehydrogenase (deaminating), encoded by nadX. The gdhA gene product
from Escherichia coli (Korber et al. J. Mol. Biol. 234:1270-1273
(1993); McPherson and Wootton Nucleic. Acids Res. 11:5257-5266
(1983)), gdh from Thermotoga maritima (Kort et al. Extremophiles
1:52-60 (1997); Lebbink, et al. J. Mol. Biol. 280:287-296 (1998));
Lebbink et al. J. Mol. Biol. 289:357-369 (1999)), and gdhA1 from
Halobacterium salinarum (Ingoldsby et al. Gene 349:237-244 (2005))
catalyze the reversible interconversion of glutamate to
2-oxoglutarate and ammonia, while favoring NADP(H), NAD(H), or
both, respectively. The ldh gene of Bacillus cereus encodes the
LeuDH protein that has a wide of range of substrates including
leucine, isoleucine, valine, and 2-aminobutanoate (Ansorge and Kula
Biotechnol Bioeng. 68:557-562 (2000); Stoyan et al. J. Biotechnol
54:77-80 (1997)). The nadX gene from Thermotoga maritime encoding
for the aspartate dehydrogenase is involved in the biosynthesis of
NAD (Yang et al. J. Biol. Chem. 278:8804-8808 (2003)).
TABLE-US-00034 Gene Accession No. GI No. Organism gdhA P00370
118547 Escherichia coli gdh P96110.4 6226595 Thermotoga maritima
gdhA1 NP_279651.1 15789827 Halobacterium salinarum ldh P0A393
61222614 Bacillus cereus nadX NP_229443.1 15644391 Thermotoga
maritima
[0381] The lysine 6-dehydrogenase (deaminating), encoded by lysDH
gene, catalyze the oxidative deamination of the .epsilon.-amino
group of L-lysine to form 2-aminoadipate-6-semialdehyde, which in
turn nonenzymatically cyclizes to form
.DELTA.1-piperideine-6-carboxylate (Misono and Nagasaki J.
Bacteriol. 150:398-401 (1982)). The lysDH gene from Geobacillus
stearothermophilus encodes a thermophilic NAD-dependent lysine
6-dehydrogenase (Heydari et al. Appl Environ. Microbiol 70:937-942
(2004)). In addition, the lysDH gene from Aeropyrum pernix K1 is
identified through homology from genome projects.
TABLE-US-00035 Gene Accession No. GI No. Organism lysDH AB052732
13429872 Geobacillus stearothermophilus lysDH NP_147035.1 14602185
Aeropyrum pernix K1 ldh P0A393 61222614 Bacillus cereus
2.3.1.a--Acyltransferase (Transferring Phosphate Group)
[0382] Exemplary phosphate transferring acyltransferases include
phosphotransacetylase, encoded by pta, and phosphotransbutyrylase,
encoded by ptb. The pta gene from E. coli encodes an enzyme that
can convert acetyl-CoA into acetyl-phosphate, and vice versa
(Suzuki, T. Biochim. Biophys. Acta 191:559-569 (1969)). This enzyme
can also utilize propionyl-CoA instead of acetyl-CoA forming
propionate in the process (Hesslinger et al. Mol. Microbiol
27:477-492 (1998)). Similarly, the ptb gene from C. acetobutylicum
encodes an enzyme that can convert butyryl-CoA into
butyryl-phosphate (Walter et al. Gene 134(1): p. 107-11 (1993));
Huang et al. J Mol Microbiol Biotechnol 2(1): p. 33-38 (2000).
Additional ptb genes can be found in butyrate-producing bacterium
L2-50 (Louis et al. J. Bacteriol. 186:2099-2106 (2004)) and
Bacillus megaterium (Vazquez et al. Curr. Microbiol 42:345-349
(2001)).
TABLE-US-00036 Gene Accession No. GI No. Organism pta NP_416800.1
16130232 Escherichia coli ptb NP_349676 15896327 Clostridium
acetobutylicum ptb AAR19757.1 38425288 butyrate-producing bacterium
L2-50 ptb CAC07932.1 10046659 Bacillus megaterium
2.6.1.a--Aminotransferase
[0383] Aspartate aminotransferase transfers an amino group from
aspartate to alpha-ketoglutarate, forming glutamate and
oxaloacetate. This conversion is catalyzed by, for example, the
gene products of aspC from Escherichia coli (Yagi et al. FEBS Lett.
100:81-84 (1979); Yagi et al. Methods Enzymol. 113:83-89 (1985)),
AAT2 from Saccharomyces cerevisiae (Yagi et al. J Biochem. 92:35-43
(1982)) and ASPS from Arabidopsis thaliana (48, 108, 225 48. de la
et al. Plant J 46:414-425 (2006); Kwok and Hanson J Exp. Bot.
55:595-604 (2004); Wilkie and Warren Protein Expr. Purif.
12:381-389 (1998)). Valine aminotransferase catalyzes the
conversion of valine and pyruvate to 2-ketoisovalerate and alanine.
The E. coli gene, avtA, encodes one such enzyme (Whalen and Berg J.
Bacteriol. 150:739-746 (1982)). This gene product also catalyzes
the amination of .alpha.-ketobutyrate to generate
.alpha.-aminobutyrate, although the amine donor in this reaction
has not been identified (Whalen and Berg J. Bacteriol. 158:571-574
(1984)). The gene product of the E. coli serC catalyzes two
reactions, phosphoserine aminotransferase and
phosphohydroxythreonine aminotransferase (Lam and Winkler J.
Bacteriol. 172:6518-6528 (1990)), and activity on
non-phosphorylated substrates could not be detected (Drewke et al.
FEBS. Lett. 390:179-182 (1996)).
TABLE-US-00037 Gene Accession No. GI No. Organism aspC NP_415448.1
16128895 Escherichia coli AAT2 P23542.3 1703040 Saccharomyces
cerevisiae ASP5 P46248.2 20532373 Arabidopsis thaliana avtA
YP_026231.1 49176374 Escherichia coli serC NP_415427.1 16128874
Escherichia coli
[0384] Cargill has developed a beta-alanine/alpha-ketoglutarate
aminotransferase for producing 3-HP from beta-alanine via
malonyl-semialdehyde (PCT/US2007/076252 (Jessen et al)). The gene
product of SkPYD4 in Saccharomyces kluyveri was also shown to
preferentially use beta-alanine as the amino group donor (Andersen
et al. FEBS. J. 274:1804-1817 (2007)). SkUGA1 encodes a homologue
of Saccharomyces cerevisiae GABA aminotransferase, UGA1 (Ramos et
al. Eur. J. Biochem. 149:401-404 (1985)), whereas SkPYD4 encodes an
enzyme involved in both .beta.-alanine and GABA transamination
(Andersen et al. FEBS. J. 274:1804-1817 (2007)).
3-Amino-2-methylpropionate transaminase catalyzes the
transformation from methylmalonate semialdehyde to
3-amino-2-methylpropionate. The enzyme has been characterized in
Rattus norvegicus and Sus scrofa and is encoded by Abat (Kakimoto
et al. Biochim. Biophys. Acta 156:374-380 (1968); Tamaki et al.
Methods Enzymol. 324:376-389 (2000)). Enzyme candidates in other
organisms with high sequence homology to 3-amino-2-methylpropionate
transaminase include Gta-1 in C. elegans and gabT in Bacillus
subtilus. Additionally, one of the native GABA aminotransferases in
E. coli, encoded by gene gabT, has been shown to have broad
substrate specificity (Liu et al. Biochemistry 43:10896-10905
(2004); Schulz et al. Appl Environ Microbiol 56:1-6 (1990)). The
gene product of puuE catalyzes the other 4-aminobutyrate
transaminase in E. coli (Kurihara et al. J. Biol. Chem.
280:4602-4608 (2005)).
TABLE-US-00038 Gene Accession No. GI No. Organism SkyPYD4
ABF58893.1 98626772 Saccharomyces kluyveri SkUGA1 ABF58894.1
98626792 Saccharomyces kluyveri UGA1 NP_011533.1 6321456
Saccharomyces cerevisiae Abat P50554.3 122065191 Rattus norvegicus
Abat P80147.2 120968 Sus scrofa Gta-1 Q21217.1 6016091
Caenorhabditis elegans gabT P94427.1 6016090 Bacillus subtilus gabT
P22256.1 120779 Escherichia coli K12 puuE NP_415818.1 16129263
Escherichia coli K12
[0385] The X-ray crystal structures of E. coli 4-aminobutyrate
transaminase unbound and bound to the inhibitor were reported (Liu
et al. Biochemistry 43:10896-10905 (2004)). The substrates binding
and substrate specificities were studied and suggested. The roles
of active site residues were studied by site-directed mutagenesis
and X-ray crystallography (Liu et al. Biochemistry 44:2982-2992
(2005)). Based on the structural information, attempt was made to
engineer E. coli 4-aminobutyrate transaminase with novel enzymatic
activity. These studies provide a base for evolving transaminase
activity for BDO pathways.
2.7.2.a--Phosphotransferase, Carboxyl Group Acceptor
[0386] Exemplary kinases include the E. coli acetate kinase,
encoded by ackA (Skarstedt and Silverstein J. Biol. Chem.
251:6775-6783 (1976)), the C. acetobutylicum butyrate kinases,
encoded by buk1 and buk2 (Walter et al. Gene 134(1):107-111 (1993)
(Huang et al. J Mol Microbiol Biotechnol 2(1):33-38 (2000)], and
the E. coli gamma-glutamyl kinase, encoded by proB (Smith et al. J.
Bacteriol. 157:545-551 (1984)). These enzymes phosphorylate
acetate, butyrate, and glutamate, respectively. The ackA gene
product from E. coli also phosphorylates propionate (Hesslinger et
al. Mol. Microbiol 27:477-492 (1998)).
TABLE-US-00039 Gene Accession No. GI No. Organism ackA NP_416799.1
16130231 Escherichia coli buk1 NP_349675 15896326 Clostridium
acetobutylicum buk2 Q97II1 20137415 Clostridium acetobutylicum proB
NP_414777.1 16128228 Escherichia coli
2.8.3.a--Coenzyme-A Transferase
[0387] In the CoA-transferase family, E. coli enzyme
acyl-CoA:acetate-CoA transferase, also known as acetate-CoA
transferase (EC 2.8.3.8), has been shown to transfer the CoA moiety
to acetate from a variety of branched and linear acyl-CoA
substrates, including isobutyrate (Matthies and Schink Appl Environ
Microbiol 58:1435-1439 (1992)), valerate (Vanderwinkel et al.
Biochem. Biophys. Res Commun. 33:902-908 (1968)) and butanoate
(Vanderwinkel, supra (1968)). This enzyme is encoded by atoA (alpha
subunit) and atoD (beta subunit) in E. coli sp. K12 (Korolev et al.
Acta Crystallogr. D Biol Crystallogr. 58:2116-2121 (2002);
Vanderwinkel, supra (1968)) and actA and cg0592 in Corynebacterium
glutamicum ATCC 13032 (Duncan et al. Appl Environ Microbiol
68:5186-5190 (2002)). Additional genes found by sequence homology
include atoD and atoA in Escherichia coli UT 189.
TABLE-US-00040 Gene Accession No. GI No. Organism atoA P76459.1
2492994 Escherichia coli K12 atoD P76458.1 2492990 Escherichia coli
K12 actA YP_226809.1 62391407 Corynebacterium glutamicum ATCC 13032
cg0592 YP_224801.1 62389399 Corynebacterium glutamicum ATCC 13032
atoA ABE07971.1 91073090 Escherichia coli UT189 atoD ABE07970.1
91073089 Escherichia coli UT189
[0388] Similar transformations are catalyzed by the gene products
of cat1, cat2, and cat3 of Clostridium kluyveri which have been
shown to exhibit succinyl-CoA, 4-hydroxybutyryl-CoA, and
butyryl-CoA acetyltransferase activity, respectively (Seedorf et
al. Proc Natl Acad Sci U.S.A. 105(6):2128-2133 (2008); Sohling and
Gottschalk J Bacteriol 178(3):871-880 (1996)].
TABLE-US-00041 Gene Accession No. GI No. Organism cat1 P38946.1
729048 Clostridium kluyveri cat2 P38942.2 1705614 Clostridium
kluyveri cat3 EDK35586.1 146349050 Clostridium kluyveri
[0389] The glutaconate-CoA-transferase (EC 2.8.3.12) enzyme from
anaerobic bacterium Acidaminococcus fermentans reacts with diacid
glutaconyl-CoA and 3-butenoyl-CoA (Mack and Buckel FEBS Lett.
405:209-212 (1997)). The genes encoding this enzyme are gctA and
gctB. This enzyme has reduced but detectable activity with other
CoA derivatives including glutaryl-CoA, 2-hydroxyglutaryl-CoA,
adipyl-CoA and acrylyl-CoA (Buckel et al. Eur. J. Biochem.
118:315-321 (1981)). The enzyme has been cloned and expressed in E.
coli (Mac et al. Eur. J. Biochem. 226:41-51 (1994)).
TABLE-US-00042 Gene Accession No. GI No. Organism gctA CAA57199.1
559392 Acidaminococcus fermentans gctB CAA57200.1 559393
Acidaminococcus fermentans
3.1.2.a--Thiolester Hydrolase (CoA Specific)
[0390] In the CoA hydrolase family, the enzyme
3-hydroxyisobutyryl-CoA hydrolase is specific for 3-HIBCoA and has
been described to efficiently catalyze the desired transformation
during valine degradation (Shimomura et al. J Biol Chem
269:14248-14253 (1994)). Genes encoding this enzyme include hibch
of Rattus norvegicus (Shimomura et al., supra (1994); Shimomura et
al. Methods Enzymol. 324:229-240 (2000) and Homo sapiens (Shimomura
et al., supra, 2000). Candidate genes by sequence homology include
hibch of Saccharomyces cerevisiae and BC_2292 of Bacillus
cereus.
TABLE-US-00043 Gene Accession No. GI No. Organism hibch Q5XIE6.2
146324906 Rattus norvegicus hibch Q6NVY1.2 146324905 Homo sapiens
hibch P28817.2 2506374 Saccharomyces cerevisiae BC_2292 Q81DR3
81434808 Bacillus cereus
[0391] The conversion of adipyl-CoA to adipate can be carried out
by an acyl-CoA hydrolase or equivalently a thioesterase. The top E.
coli gene candidate is tesB (Naggert et al. J Biol Chem.
266(17):11044-11050 (1991)] which shows high similarity to the
human acot8 which is a dicarboxylic acid acetyltransferase with
activity on adipyl-CoA (Westin et al. J Biol Chem 280(46):
38125-38132 (2005). This activity has also been characterized in
the rat liver (Deana, Biochem Int. 26(4): p. 767-773 (1992)).
TABLE-US-00044 Gene Accession No. GI No. Organism tesB NP_414986
16128437 Escherichia coli acot8 CAA15502 3191970 Homo sapiens acot8
NP_570112 51036669 Rattus norvegicus
[0392] Other potential E. coli thiolester hydrolases include the
gene products of tesA (Bonner and Bloch, J Biol Chem.
247(10):3123-3133 (1972)), ybgC (Kuznetsova et al., FEMS Microbiol
Rev. 29(2):263-279 (2005); Zhuang et al., FEBS Lett.
516(1-3):161-163 (2002)) paaI (Song et al., J Biol Chem.
281(16):11028-11038 (2006)), and ybdB (Leduc et al., J Bacteriol.
189(19):7112-7126 (2007)).
TABLE-US-00045 Gene Accession No. GI No. Organism tesA NP_415027
16128478 Escherichia coli ybgC NP_415264 16128711 Escherichia coli
paaI NP_415914 16129357 Escherichia coli ybdB NP_415129 16128580
Escherichia coli
[0393] Several eukaryotic acetyl-CoA hydrolases (EC 3.1.2.1) have
broad substrate specificity. The enzyme from Rattus norvegicus
brain (Robinson et al. Biochem. Biophys. Res. Commun. 71:959-965
(1976)) can react with butyryl-CoA, hexanoyl-CoA and
malonyl-CoA.
TABLE-US-00046 Gene Accession No. GI No. Organism acot12
NP_570103.1 18543355 Rattus norvegicus
4.1.1.a--Carboxy-Lyase
[0394] An exemplary carboxy-lyase is acetolactate decarboxylase
which participates in citrate catabolism and branched-chain amino
acid biosynthesis, converting 2-acetolactate to acetoin. In
Lactococcus lactis the enzyme is composed of six subunits, encoded
by gene aldB, and is activated by valine, leucine and isoleucine
(Goupil et al. Appl. Environ. Microbiol. 62:2636-2640 (1996);
Goupil-Feuillerat et al. J. Bacteriol. 182:5399-5408 (2000)). This
enzyme has been overexpressed and characterized in E. coli (Phalip
et al. FEBS Lett. 351:95-99 (1994)). In other organisms the enzyme
is a dimer, encoded by aldC in Streptococcus thermophilus (Monnet
et al. Lett. Appl. Microbiol. 36:399-405 (2003)), aldB in Bacillus
brevis (Diderichsen et al. J. Bacteriol. 172:4315-4321 (1990);
Najmudin et al. Acta Crystallogr. D. Biol. Crystallogr.
59:1073-1075 (2003)) and budA from Enterobacter aerogenes
(Diderichsen et al. J. Bacteriol. 172:4315-4321 (1990)). The enzyme
from Bacillus brevis was cloned and overexpressed in Bacillus
subtilis and characterized crystallographically (Najmudin et al.
Acta Crystallogr. D. Biol. Crystallogr. 59:1073-1075 (2003)).
Additionally, the enzyme from Leuconostoc lactis has been purified
and characterized but the gene has not been isolated (O'Sullivan et
al. FEMS Microbiol. Lett. 194:245-249 (2001)).
TABLE-US-00047 Gene Accession No. GI No. Organism aldB NP_267384.1
15673210 Lactococcus lactis aldC Q8L208 75401480 Streptococcus
thermophilus aldB P23616.1 113592 Bacillus brevis budA P05361.1
113593 Enterobacter aerogenes
[0395] Aconitate decarboxylase catalyzes the final step in
itaconate biosynthesis in a strain of Candida and also in the
filamentous fungus Aspergillus terreus (Bonnarme et al. J
Bacteriol. 177:3573-3578 (1995); Willke and Vorlop Appl Microbiol
Biotechnol 56:289-295 (2001)). Although itaconate is a compound of
biotechnological interest, the aconitate decarboxylase gene or
protein sequence has not been reported to date.
[0396] 4-oxalocronate decarboxylase has been isolated from numerous
organisms and characterized. Genes encoding this enzyme include
dmpH and dmpE in Pseudomonas sp. (strain 600) (Shingler et al. J
Bacteriol. 174:711-724 (1992)), xylII and xylIII from Pseudomonas
putida (Kato and Asano Arch. Microbiol 168:457-463 (1997); Lian and
Whitman J. Am. Chem. Soc. 116:10403-10411 (1994); Stanley et al.
Biochemistry 39:3514 (2000)) and Reut_B5691 and Reut_B5692 from
Ralstonia eutropha JMP134 (Hughes et al. J Bacteriol. 158:79-83
(1984)). The genes encoding the enzyme from Pseudomonas sp. (strain
600) have been cloned and expressed in E. coli (Shingler et al. J
Bacteriol. 174:711-724 (1992)).
TABLE-US-00048 Gene Accession No. GI No. Organism dmpH CAA43228.1
45685 Pseudomonas sp. CF600 dmpE CAA43225.1 45682 Pseudomonas sp.
CF600 xylII YP_709328.1 111116444 Pseudomonas putida xylIII
YP_709353.1 111116469 Pseudomonas putida Reut_B5691 YP_299880.1
73539513 Ralstonia eutropha JMP134 Reut_B5692 YP_299881.1 73539514
Ralstonia eutropha JMP134
[0397] An additional class of decarboxylases has been characterized
that catalyze the conversion of cinnamate (phenylacrylate) and
substituted cinnamate derivatives to the corresponding styrene
derivatives. These enzymes are common in a variety of organisms and
specific genes encoding these enzymes that have been cloned and
expressed in E. coli are: pad 1 from Saccharomyces cerevisae
(Clausen et al. Gene 142:107-112 (1994)), pdc from Lactobacillus
plantarum (Barthelmebs et al. Appl Environ Microbiol 67:1063-1069
(2001); Qi et al. Metab Eng 9:268-276 (2007); Rodriguez et al. J.
Agric. Food Chem. 56:3068-3072 (2008)), pofK (pad) from Klebsiella
oxytoca (Hashidoko et al. Biosci. Biotech. Biochem. 58:217-218
(1994); Uchiyama et al. Biosci. Biotechnol. Biochem. 72:116-123
(2008)), Pedicoccus pentosaceus (Barthelmebs et al. Appl Environ
Microbiol 67:1063-1069 (2001)), and padC from Bacillus subtilis and
Bacillus pumilus (Lingen et al. Protein Eng 15:585-593 (2002)). A
ferulic acid decarboxylase from Pseudomonas fluorescens also has
been purified and characterized (Huang et al. J. Bacteriol.
176:5912-5918 (1994)). Importantly, this class of enzymes have been
shown to be stable and do not require either exogenous or
internally bound co-factors, thus making these enzymes ideally
suitable for biotransformations (Sariaslani, Annu. Rev. Microbiol.
61:51-69 (2007)).
TABLE-US-00049 Accession Gene No. GI No. Organism pad1 AB368798
188496948 Saccharomyces cerevisae BAG32372.1 188496949 pdc U63827
1762615, 1762616 Lactobacillus plantarum AAC45282.1 pofK AB330293,
149941607, 149941608 Klebsiella oxytoca (pad) BAF65031.1 padC
AF017117 2394281, 2394282 Bacillus subtilis AAC46254.1 pad AJ276891
11322456, 11322458 Pedicoccus pentosaceus CAC16794.1 pad AJ278683
11691809, 11691810 Bacillus pumilus CAC18719.1
[0398] Additional decarboxylase enzymes can form succinic
semialdehyde from alpha-ketoglutarate. These include the
alpha-ketoglutarate decarboxylase enzymes from Euglena gracilis
(Shigeoka et al. Biochem. J. 282(Pt 2):319-323 (1992); Shigeoka and
Nakano Arch. Biochem. Biophys. 288:22-28 (1991); Shigeoka and
Nakano Biochem. J. 292 (Pt 2):463-467 (1993)), whose corresponding
gene sequence has yet to be determined, and from Mycobacterium
tuberculosis (Tian et al. Proc Natl Acad Sci U.S.A. 102:10670-10675
(2005)). In addition, glutamate decarboxylase enzymes can convert
glutamate into 4-aminobutyrate such as the products of the E. coli
gadA and gadB genes (De Biase et al. Protein. Expr. Purif.
8:430-438 (1993)).
TABLE-US-00050 Gene Accession No. GI No. Organism kgd O50463.4
160395583 Mycobacterium tuberculosis gadA NP_417974 16131389
Escherichia coli gadB NP_416010 16129452 Escherichia coli
Keto-Acid Decarboxylases
[0399] Pyruvate decarboxylase (PDC, EC 4.1.1.1), also termed
keto-acid decarboxylase, is a key enzyme in alcoholic fermentation,
catalyzing the decarboxylation of pyruvate to acetaldehyde. This
enzyme has a broad substrate range for aliphatic 2-keto acids
including 2-ketobutyrate, 2-ketovalerate, 3-hydroxypyruvate and
2-phenylpyruvate (Berg et al. Science 318:1782-1786 (2007)). The
PDC from Zymomonas mobilus, encoded by pdc, has been a subject of
directed engineering studies that altered the affinity for
different substrates (Siegert et al. Protein Eng Des Sel 18:345-357
(2005)). The PDC from Saccharomyces cerevisiae has also been
extensively studied, engineered for altered activity, and
functionally expressed in E. coli (Killenberg-Jabs et al. Eur. J.
Biochem. 268:1698-1704 (2001); Li and Jordan Biochemistry
38:10004-10012 (1999); ter Schure et al. Appl. Environ. Microbiol.
64:1303-1307 (1998)). The crystal structure of this enzyme is
available (Killenberg-Jabs Eur. J. Biochem. 268:1698-1704 (2001)).
Other well-characterized PDC candidates include the enzymes from
Acetobacter pasteurians (Chandra et al. Arch. Microbiol.
176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al. Eur.
J. Biochem. 269:3256-3263 (2002)).
TABLE-US-00051 Gene Accession No. GI No. Organism pdc P06672.1
118391 Zymomonas mobilus pdc1 P06169 30923172 Saccharomyces
cerevisiae pdc Q8L388 75401616 Acetobacter pasteurians pdc1 Q12629
52788279 Kluyveromyces lactis
[0400] Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a
broad substrate range and has been the target of enzyme engineering
studies. The enzyme from Pseudomonas putida has been extensively
studied and crystal structures of this enzyme are available (Hasson
et al. Biochemistry 37:9918-9930 (1998); Polovnikova et al.
Biochemistry 42:1820-1830 (2003)). Site-directed mutagenesis of two
residues in the active site of the Pseudomonas putida enzyme
altered the affinity (Km) of naturally and non-naturally occurring
substrates (Siegert Protein Eng Des Sel 18:345-357 (2005)). The
properties of this enzyme have been further modified by directed
engineering (Lingen et al. Protein Eng 15:585-593 (2002)); Lingen
Chembiochem 4:721-726 (2003)). The enzyme from Pseudomonas
aeruginosa, encoded by mdlC, has also been characterized
experimentally (Barrowman et al. FEMS Microbiology Letters 34:57-60
(1986)). Additional gene candidates from Pseudomonas stutzeri,
Pseudomonas fluorescens and other organisms can be inferred by
sequence homology or identified using a growth selection system
developed in Pseudomonas putida (Henning et al. Appl. Environ.
Microbiol. 72:7510-7517 (2006)).
TABLE-US-00052 Gene Accession No. GI No. Organism mdlC P20906.2
3915757 Pseudomonas putida mdlC Q9HUR2.1 81539678 Pseudomonas
aeruginosa dpgB ABN80423.1 126202187 Pseudomonas stutzeri ilvB-1
YP_260581.1 70730840 Pseudomonas fluorescens
4.2.1.a--Hydro-Lyase
[0401] The 2-(hydroxymethyl)glutarate dehydratase of Eubacterium
barkeri is an exemplary hydro-lyase. This enzyme has been studied
in the context of nicotinate catabolism and is encoded by hmd
(Alhapel et al. Proc Natl Acad Sci USA 103:12341-12346 (2006)).
Similar enzymes with high sequence homology are found in
Bacteroides capillosus, Anaerotruncus colihominis, and
Natranaerobius thermophilius.
TABLE-US-00053 Gene Accession No. GI No. Organism hmd ABC88407.1
86278275 Eubacterium barkeri BACCAP_02294 ZP_02036683.1 154498305
Bacteroides capillosus ATCC 29799 ANACOL_02527 ZP_02443222.1
167771169 Anaerotruncus colihominis DSM 17241 NtherDRAFT_2368
ZP_02852366.1 169192667 Natranaerobius thermophilus JW/NM-WN-
LF
[0402] A second exemplary hydro-lyase is fumarate hydratase, an
enzyme catalyzing the dehydration of malate to fumarate. A wealth
of structural information is available for this enzyme and
researchers have successfully engineered the enzyme to alter
activity, inhibition and localization (Weaver, T. Acta Crystallogr.
D Biol Crystallogr. 61:1395-1401 (2005)). Additional fumarate
hydratases include those encoded by fumC from Escherichia coli
(Estevez et al. Protein Sci. 11:1552-1557 (2002); Hong and Lee
Biotechnol. Bioprocess Eng. 9:252-255 (2004); Rose and Weaver Proc
Natl Acad Sci USA 101:3393-3397 (2004)), Campylobacter jejuni
(Smith et al. Int. J Biochem. Cell Biol 31:961-975 (1999)) and
Thermus thermophilus (Mizobata et al. Arch. Biochem. Biophys.
355:49-55 (1998)), and fumH from Rattus norvegicus (Kobayashi et
al. J Biochem. 89:1923-1931(1981)). Similar enzymes with high
sequence homology include fum1 from Arabidopsis thaliana and fumC
from Corynebacterium glutamicum.
TABLE-US-00054 Gene Accession No. GI No. Organism fumC P05042.1
120601 Escherichia coli K12 fumC O69294.1 9789756 Campylobacter
jejuni fumC P84127 75427690 Thermus thermophilus fumH P14408.1
120605 Rattus norvegicus fum1 P93033.2 39931311 Arabidopsis
thaliana fumC Q8NRN8.1 39931596 Corynebacterium glutamicum
[0403] Citramalate hydrolyase, also called 2-methylmalate
dehydratase, converts 2-methylmalate to mesaconate. 2-Methylmalate
dehydratase activity was detected in Clostridium tetanomorphum,
Morganella morganii, Citrobacter amalonaticus in the context of the
glutamate degradation VI pathway (Kato and Asano Arch. Microbiol
168:457-463 (1997)); however the genes encoding this enzyme have
not been sequenced to date.
[0404] The gene product of crt from C. acetobutylicum catalyzes the
dehydration of 3-hydroxybutyryl-CoA to crotonyl-CoA (Atsumi et al.
Metab Eng.; 29 (2007)); Boynton et al. Journal of Bacteriology
178:3015-3024 (1996)). The enoyl-CoA hydratases, phaA and phaB, of
P. putida are believed to carry out the hydroxylation of double
bonds during phenylacetate catabolism; (Olivera et al. Proc Natl
Acad Sci USA 95(11):6419-6424 (1998)). The paaA and paaB from P.
fluorescens catalyze analogous transformations (14 Olivera et al.,
supra, 1998). Lastly, a number of Escherichia coli genes have been
shown to demonstrate enoyl-CoA hydratase functionality including
maoC (Park and Lee J Bacteriol 185(18):5391-5397 (2003)), paaF
(Park and Lee Biotechnol Bioeng. 86(6):681-686 (2004a)); Park and
Lee Appl Biochem Biotechnol. 113-116: 335-346 (2004b)); Ismail et
al. Eur J Biochem 270(14):p. 3047-3054 (2003), and paaG (Park and
Lee, supra, 2004; Park and Lee supra, 2004b; Ismail et al., supra,
2003).
TABLE-US-00055 Gene Accession No. GI No. Organism maoC NP_415905.1
16129348 Escherichia coli paaF NP_415911.1 16129354 Escherichia
coli paaG NP_415912.1 16129355 Escherichia coli crt NP_349318.1
15895969 Clostridium acetobutylicum paaA NP_745427.1 26990002
Pseudomonas putida paaB NP_745426.1 26990001 Pseudomonas putida
phaA ABF82233.1 106636093 Pseudomonas fluorescens phaB ABF82234.1
106636094 Pseudomonas fluorescens
[0405] The E. coli genes fadA and fadB encode a multienzyme complex
that exhibits ketoacyl-CoA thiolase, 3-hydroxyacyl-CoA
dehydrogenase, and enoyl-CoA hydratase activities (Yang et al.
Biochemistry 30(27): p. 6788-6795 (1991); Yang et al. J Biol Chem
265(18): p. 10424-10429 (1990); Yang et al. J Biol Chem 266(24): p.
16255 (1991); Nakahigashi and Inokuchi Nucleic Acids Res 18(16): p.
4937 (1990)). The fadI and fadJ genes encode similar functions and
are naturally expressed only anaerobically (Campbell et al. Mol
Microbiol 47(3): p. 793-805 (2003). A method for producing
poly[(R)-3-hydroxybutyrate] in E. coli that involves activating
fadB (by knocking out a negative regulator, fadR) and co-expressing
a non-native ketothiolase (phaA from Ralstonia eutropha) has been
described previously (Sato et al. J Biosci Bioeng 103(1): 38-44
(2007)). This work clearly demonstrates that a .beta.-oxidation
enzyme, in particular the gene product of fadB which encodes both
3-hydroxyacyl-CoA dehydrogenase and enoyl-CoA hydratase activities,
can function as part of a pathway to produce longer chain molecules
from acetyl-CoA precursors.
TABLE-US-00056 Gene Accession No. GI No. Organism fadA YP_026272.1
49176430 Escherichia coli fadB NP_418288.1 16131692 Escherichia
coli fadI NP_416844.1 16130275 Escherichia coli fadJ NP_416843.1
16130274 Escherichia coli fadR NP_415705.1 16129150 Escherichia
coli
4.3.1.a--Ammonia-Lyase
[0406] Aspartase (EC 4.3.1.1), catalyzing the deamination of
aspartate to fumarate, is a widespread enzyme in microorganisms,
and has been characterized extensively (Viola, R. E. Adv. Enzymol.
Relat Areas Mol. Biol 74:295-341 (2000)). The crystal structure of
the E. coli aspartase, encoded by aspA, has been solved (Shi et al.
Biochemistry 36:9136-9144 (1997)). The E. coli enzyme has also been
shown to react with alternate substrates
aspartatephenylmethylester, asparagine, benzyl-aspartate and malate
(Ma et al. Ann N.Y. Acad Sci 672:60-65 (1992)). In a separate
study, directed evolution was been employed on this enzyme to alter
substrate specificity (Asano et al. Biomol. Eng 22:95-101 (2005)).
Enzymes with aspartase functionality have also been characterized
in Haemophilus influenzae (Sjostrom et al. Biochim. Biophys. Acta
1324:182-190 (1997)), Pseudomonas fluorescens (Takagi et al. J.
Biochem. 96:545-552 (1984)), Bacillus subtilus (Sjostrom et al.
Biochim. Biophys. Acta 1324:182-190 (1997)) and Serratia marcescens
(Takagi and Kisumi J Bacteriol. 161:1-6 (1985)).
TABLE-US-00057 Gene Accession No. GI No. Organism aspA NP_418562
90111690 Escherichia coli K12 subsp. MG1655 aspA P44324.1 1168534
Haemophilus influenzae aspA P07346.1 114273 Pseudomonas fluorescens
ansB P26899.1 114271 Bacillus subtilus aspA P33109.1 416661
Serratia marcescens
[0407] 3-methylaspartase (EC 4.3.1.2), also known as
beta-methylaspartase or 3-methylaspartate ammonia-lyase, catalyzes
the deamination of threo-3-methylasparatate to mesaconate. The
3-methylaspartase from Clostridium tetanomorphum has been cloned,
functionally expressed in E. coli, and crystallized (Asuncion et
al. Acta Crystallogr. D Biol Crystallogr. 57:731-733 (2001);
Asuncion et al. J Biol Chem. 277:8306-8311 (2002); Botting et al.
Biochemistry 27:2953-2955 (1988); Goda et al. Biochemistry
31:10747-10756 (1992). In Citrobacter amalonaticus, this enzyme is
encoded by BAA28709 (Kato and Asano Arch. Microbiol 168:457-463
(1997)). 3-Methylaspartase has also been crystallized from E. coli
YG1002 (Asano and Kato FEMS Microbiol Lett. 118:255-258 (1994))
although the protein sequence is not listed in public databases
such as GenBank. Sequence homology can be used to identify
additional candidate genes, including CTC_02563 in C. tetani and
ECs0761 in Escherichia coli O157:H7.
TABLE-US-00058 Gene Accession No. GI No. Organism MAL AAB24070.1
259429 Clostridium tetanomorphum BAA28709 BAA28709.1 3184397
Citrobacter amalonaticus CTC_02563 NP_783085.1 28212141 Clostridium
tetani ECs0761 BAB34184.1 13360220 Escherichia coli O157:H7 str.
Sakai
[0408] Ammonia-lyase enzyme candidates that form enoyl-CoA products
include beta-alanyl-CoA ammonia-lyase (EC 4.3.1.6), which
deaminates beta-alanyl-CoA, and 3-aminobutyryl-CoA ammonia-lyase
(EC 4.3.1.14). Two beta-alanyl-CoA ammonia lyases have been
identified and characterized in Clostridium propionicum (Herrmann
et al. FEBS J. 272:813-821 (2005)). No other beta-alanyl-CoA
ammonia lyases have been studied to date, but gene candidates can
be identified by sequence similarity. One such candidate is
MXAN_4385 in Myxococcus xanthus.
TABLE-US-00059 Gene Accession No. GI No. Organism ac12 CAG29275.1
47496504 Clostridium propionicum acl1 CAG29274.1 47496502
Clostridium propionicum MXAN_4385 YP_632558.1 108756898 Myxococcus
xanthus
5.3.3.a--Isomerase
[0409] The 4-hydroxybutyryl-CoA dehydratases from both Clostridium
aminobutyrium and C. kluyveri catalyze the reversible conversion of
4-hydroxybutyryl-CoA to crotonyl-CoA and posses an intrinsic
vinylacetyl-CoA .DELTA.-isomerase activity (Scherf and Buckel Eur.
J Biochem. 215:421-429 (1993); Scherf et al. Arch. Microbiol
161:239-245 (1994)). Both native enzymes were purified and
characterized, including the N-terminal amino acid sequences
(Scherf and Buckel, supra, 1993; Scherf et al., supra, 1994). The
abfD genes from C. aminobutyrium and C. kluyveri match exactly with
these N-terminal amino acid sequences, thus are encoding the
4-hydroxybutyryl-CoA dehydratases/vinylacetyl-CoA
.DELTA.-isomerase. In addition, the abfD gene from Porphyromonas
gingivalis ATCC 33277 is identified through homology from genome
projects.
TABLE-US-00060 Gene Accession No. GI No. Organism abfD
YP_001396399.1 153955634 Clostridium kluyveri DSM 555 abfD P55792
84028213 Clostridium aminobutyricum abfD YP_001928843 188994591
Porphyromonas gingivalis ATCC 33277
5.4.3.a--Aminomutase
[0410] Lysine 2,3-aminomutase (EC 5.4.3.2) is an exemplary
aminomutase that converts lysine to (3S)-3,6-diaminohexanoate,
shifting an amine group from the 2- to the 3-position. The enzyme
is found in bacteria that ferment lysine to acetate and butyrate,
including as Fusobacterium nuleatum (kamA) (Barker et al. J.
Bacteriol. 152:201-207 (1982)) and Clostridium subterminale (kamA)
(Chirpich et al. J. Biol. Chem. 245:1778-1789 (1970)). The enzyme
from Clostridium subterminale has been crystallized (Lepore et al.
Proc. Natl. Acad. Sci. U.S.A 102:13819-13824 (2005)). An enzyme
encoding this function is also encoded by yodO in Bacillus subtilus
(Chen et al. Biochem. J. 348 Pt 3:539-549 (2000)). The enzyme
utilizes pyridoxal 5'-phosphate as a cofactor, requires activation
by S-Adenosylmethoionine, and is stereoselective, reacting with the
only with L-lysine. The enzyme has not been shown to react with
alternate substrates.
TABLE-US-00061 Gene Accession No. GI No. Organism yodO O34676.1
4033499 Bacillus subtilus kamA Q9XBQ8.1 75423266 Clostridium
subterminale kamA Q8RHX4 81485301 Fusobacterium nuleatum subsp.
nuleatum
[0411] A second aminomutase, beta-lysine 5,6-aminomutase (EC
5.4.3.3), catalyzes the next step of lysine fermentation to acetate
and butyrate, which transforms (3S)-3,6-diaminohexanoate to
(3S,5S)-3,5-diaminohexanoate, shifting a terminal amine group from
the 6- to the 5-position. This enzyme also catalyzes the conversion
of lysine to 2,5-diaminohexanoate and is also called
lysine-5,6-aminomutase (EC 5.4.3.4). The enzyme has been
crystallized in Clostridium sticklandii (kamD, kamE) (Berkovitch et
al. Proc. Natl. Acad. Sci. U.S.A 101:15870-15875 (2004)). The
enzyme from Porphyromonas gingivalis has also been characterized
(Tang et al. Biochemistry 41:8767-8776 (2002)).
TABLE-US-00062 Gene Accession No. GI No. Organism kamD AAC79717.1
3928904 Clostridium sticklandii kamE AAC79718.1 3928905 Clostridium
sticklandii kamD NC_002950.2 34539880, 34540809 Porphyromonas
gingivalis W83 kamE NC_002950.2 34539880, 34540810 Porphyromonas
gingivalis W83
[0412] Ornithine 4,5-aminomutase (EC 5.4.3.5) converts D-ornithine
to 2,4-diaminopentanoate, also shifting a terminal amine to the
adjacent carbon. The enzyme from Clostridium sticklandii is encoded
by two genes, oraE and oraS, and has been cloned, sequenced and
expressed in E. coli (Chen et al. J. Biol. Chem. 276:44744-44750
(2001)). This enzyme has not been characterized in other organisms
to date.
TABLE-US-00063 Gene Accession No. GI No. Organism oraE AAK72502
17223685 Clostridium sticklandii oraS AAK72501 17223684 Clostridium
sticklandii
[0413] Tyrosine 2,3-aminomutase (EC 5.4.3.6) participates in
tyrosine biosynthesis, reversibly converting tyrosine to
3-amino-3-(4-hydroxyphenyl)propanoate by shifting an amine from the
2- to the 3-position. In Streptomyces globisporus the enzyme has
also been shown to react with tyrosine derivatives (Christenson et
al. Biochemistry 42:12708-12718 (2003)). Sequence information is
not available.
[0414] Leucine 2,3-aminomutase (EC 5.4.3.7) converts L-leucine to
beta-leucine during leucine degradation and biosynthesis. An assay
for leucine 2,3-aminomutase detected activity in many organisms
(Poston, J. M. Methods Enzymol. 166:130-135 (1988)) but genes
encoding the enzyme have not been identified to date.
[0415] Cargill has developed a novel 2,3-aminomutase enzyme to
convert L-alanine to .beta.-alanine, thus creating a pathway from
pyruvate to 3-HP in four biochemical steps (Liao et al., U.S.
Publication No. 2005-0221466).
6.2.1.a--Acid-Thiol Ligase
[0416] An exemplary acid-thiol ligase is the gene products of sucCD
of E. coli which together catalyze the formation of succinyl-CoA
from succinate with the concaminant consumption of one ATP, a
reaction which is reversible in vivo (Buck et al. Biochemistry
24(22): p. 6245-6252 (1985)). Additional exemplary CoA-ligases
include the rat dicarboxylate-CoA ligase for which the sequence is
yet uncharacterized (Vamecq et al. Biochem J. 230(3): p. 683-693
(1985)), either of the two characterized phenylacetate-CoA ligases
from P. chrysogenum (Lamas-Maceiras et al. Biochem J 395(1):147-155
(2006); Wang et al. Biochem Biophys Res Commun, 360(2):453-458
(2007)), the phenylacetate-CoA ligase from Pseudomonas putida
(Martinez-Blanco et al. J Biol Chem. 265(12):7084-7090 (1990)), and
the 6-carboxyhexanoate-CoA ligase from Bacillus subtilis (Bower et
al. J Bacteriol 178(14):4122-4130 (1996)).
TABLE-US-00064 Gene Accession No. GI No. Organism sucC NP_415256.1
16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli
phl CAJ15517.1 77019264 Penicillium chrysogenum phlB ABS19624.1
152002983 Penicillium chrysogenum paaF AAC24333.2 22711873
Pseudomonas putida bioW NP_390902.2 50812281 Bacillus subtilis
Example V
Exemplary BDO Pathway from Succinyl-CoA
[0417] This example describes exemplary BDO pathways from
succinyl-CoA.
[0418] BDO pathways from succinyl-CoA are described herein and have
been described previously (see U.S. application Ser. No.
12/049,256, filed Mar. 14, 2008, and PCT application serial No.
US08/57168, filed Mar. 14, 2008, each of which is incorporated
herein by reference). Additional pathways are shown in FIG. 8A.
Enzymes of such exemplary BDO pathways are listed in Table 15,
along with exemplary genes encoding these enzymes.
[0419] Briefly, succinyl-CoA can be converted to succinic
semialdehyde by succinyl-CoA reductase (or succinate semialdehyde
dehydrogenase) (EC 1.2.1.b). Succinate semialdehyde can be
converted to 4-hydroxybutyrate by 4-hydroxybutyrate dehydrogenase
(EC 1.1.1.a), as previously described. Alternatively, succinyl-CoA
can be converted to 4-hydroxybutyrate by succinyl-CoA reductase
(alcohol forming) (EC 1.1.1.c). 4-Hydroxybutyrate can be converted
to 4-hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA transferase (EC
2.8.3.a), as previously described, or by 4-hydroxybutyryl-CoA
hydrolase (EC 3.1.2.a) or 4-hydroxybutyryl-CoA ligase (or
4-hydroxybutyryl-CoA synthetase) (EC 6.2.1.a). Alternatively,
4-hydroxybutyrate can be converted to 4-hydroxybutyryl-phosphate by
4-hydroxybutyrate kinase (EC 2.7.2.a), as previously described.
4-Hydroxybutyryl-phosphate can be converted to 4-hydroxybutyryl-CoA
by phosphotrans-4-hydroxybutyrylase (EC 2.3.1.a), as previously
described. Alternatively, 4-hydroxybutyryl-phosphate can be
converted to 4-hydroxybutanal by 4-hydroxybutanal dehydrogenase
(phosphorylating) (EC 1.2.1.d). 4-Hydroxybutyryl-CoA can be
converted to 4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or
4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). Alternatively,
4-hydroxybutyryl-CoA can be converted to 1,4-butanediol by
4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c).
4-Hydroxybutanal can be converted to 1,4-butanediol by
1,4-butanediol dehydrogenase (EC 1.1.1.a), as previously
described.
TABLE-US-00065 TABLE 15 BDO pathway from succinyl-CoA. EC Desired
GenBank ID FIG. class substrate Desired product Enzyme name Gene
name (if available) Organism Known Substrates 8A 1.2.1.b
succinyl-CoA succinic succinyl-CoA sucD P38947.1 Clostridium
kluyveri succinyl-CoA semialdehyde reductase (or succinate
semialdehyde dehydrogenase) sucD NP_904963.1 Porphyromonas
succinyl-CoA gingivalis Msed_0709 YP_001190808.1 Metallosphaera
sedula malonyl-CoA 8A 1.1.1.a succinate 4- 4-hydroxy- 4hbd
YP_726053.1 Ralstonia eutropha 4-hydroxybutyrate semialdehyde
hydroxybutyrate butyrate H16 dehydrogenase 4hbd L21902.1
Clostridium kluyveri 4-hydroxybutyrate DSM 555 4hbd Q94B07
Arabidopsis thaliana 4-hydroxybutyrate 8A 1.1.1.c succinyl-CoA 4-
succinyl-CoA adhE2 AAK09379.1 Clostridium butanoyl-CoA
hydroxybutyrate reductase acetobutylicum (alcohol forming) mcr
AAS20429.1 Chloroflexus malonyl-CoA aurantiacus FAR AAD38039.1
Simmondsia chinensis long chain acyl- CoA 8A 2.8.3.a 4-
4-hydroxybutyryl- 4-hydroxy- cat1, cat2, P38946.1, Clostridium
kluyveri succinate, 4- hydroxybutyrate CoA butyryl-CoA cat3
P38942.2, hydroxybutyrate, transferase EDK35586.1 butyrate gctA,
gctB CAA57199.1, Acidaminococcus glutarate CAA57200.1 fermentans
atoA, atoD P76459.1, Escherichia coli butanoate P76458.1 8A 3.1.2.a
4- 4- 4-hydroxy- tesB NP_414986 Escherichia coli adipyl-CoA
hydroxybutyrate hydroxybutyryl- butyryl-CoA CoA hydrolase acot12
NP_570103.1 Rattus norvegicus butyryl-CoA hibch Q6NVY1.2 Homo
sapiens 3- hydroxypropanoyl- CoA 8A 6.2.1.a 4- 4- 4-hydroxy- sucCD
NP_415256.1, Escherichia coli succinate hydroxybutyrate
hydroxybutyryl- butyryl-CoA AAC73823.1 CoA ligase (or 4- hydroxy-
butyryl-CoA synthetase) phl CAJ15517.1 Penicillium phenylacetate
chrysogenum bioW NP_390902.2 Bacillus subtilis 6-carboxyhexanoate
8A 2.7.2.a 4- 4- 4-hydroxy- ackA NP_416799.1 Escherichia coli
acetate, propionate hydroxybutyrate hydroxybutyryl- butyrate
phosphate kinase buk1 NP_349675 Clostridium butyrate acetobutylicum
buk2 Q97II1 Clostridium butyrate acetobutylicum 8A 2.3.1.a 4- 4-
phospho- ptb NP_349676 Clostridium butyryl-phosphate
hydroxybutyryl- hydroxybutyryl- trans-4- acetobutylicum phosphate
CoA hydroxy- butyrylase ptb AAR19757.1 butyrate-producing
butyryl-phosphate bacterium L2-50 ptb CAC07932.1 Bacillus
megaterium butyryl-phosphate 8A 1.2.1.d 4- 4-hydroxybutanal
4-hydroxy- asd NP_417891.1 Escherichia coli L-4-aspartyl-
hydroxybutyryl- butanal phosphate phosphate dehydrogenase
(phosphoryl- ating) proA NP_414778.1 Escherichia coli L-glutamyl-5-
phospate gapA P0A9B2.2 Escherichia coli Glyceraldehyde-3- phosphate
8A 1.2.1.b 4- 4-hydroxybutanal 4-hydroxy- sucD P38947.1 Clostridium
kluyveri succinyl-CoA hydroxybutyryl- butyryl-CoA CoA reductase (or
4- hydroxybutanal dehydrogenase) sucD NP_904963.1 Porphyromonas
succinyl-CoA gingivalis Msed_0709 YP_001190808.1 Metallosphaera
sedula malonyl-CoA 8A 1.1.1.c 4- 1,4-butanediol 4-hydroxy- adhE2
AAK09379.1 Clostridium butanoyl-CoA hydroxybutyryl- butyryl-CoA
acetobutylicum CoA reductase (alcohol forming) mcr AAS20429.1
Chloroflexus malonyl-CoA aurantiacus FAR AAD38039.1 Simmondsia
chinensis long chain acyl- CoA 8A 1.1.1.a 4- 1,4-butanediol
1,4-butanediol ADH2 NP_014032.1 Saccharymyces general
hydroxybutanal dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium kluyveri
Succinate DSM 555 semialdehyde
Example VI
Additional Exemplary BDO Pathways from Alpha-Ketoglutarate
[0420] This example describes exemplary BDO pathways from
alpha-ketoglutarate.
[0421] BDO pathways from succinyl-CoA are described herein and have
been described previously (see U.S. application Ser. No.
12/049,256, filed Mar. 14, 2008, and PCT application serial No.
US08/57168, filed Mar. 14, 2008, each of which is incorporated
herein by reference). Additional pathways are shown in FIG. 8B.
Enzymes of such exemplary BDO pathways are listed in Table 16,
along with exemplary genes encoding these enzymes.
[0422] Briefly, alpha-ketoglutarate can be converted to succinic
semialdehyde by alpha-ketoglutarate decarboxylase (EC 4.1.1.a), as
previously described. Alternatively, alpha-ketoglutarate can be
converted to glutamate by glutamate dehydrogenase (EC 1.4.1.a).
4-Aminobutyrate can be converted to succinic semialdehyde by
4-aminobutyrate oxidoreductase (deaminating) (EC 1.4.1.a) or
4-aminobutyrate transaminase (EC 2.6.1.a). Glutamate can be
converted to 4-aminobutyrate by glutamate decarboxylase (EC
4.1.1.a). Succinate semialdehyde can be converted to
4-hydroxybutyrate by 4-hydroxybutyrate dehydrogenase (EC 1.1.1.a),
as previously described. 4-Hydroxybutyrate can be converted to
4-hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA transferase (EC
2.8.3.a), as previously described, or by 4-hydroxybutyryl-CoA
hydrolase (EC 3.1.2.a), or 4-hydroxybutyryl-CoA ligase (or
4-hydroxybutyryl-CoA synthetase) (EC 6.2.1.a). 4-Hydroxybutyrate
can be converted to 4-hydroxybutyryl-phosphate by 4-hydroxybutyrate
kinase (EC 2.7.2.a). 4-Hydroxybutyryl-phosphate can be converted to
4-hydroxybutyryl-CoA by phosphotrans-4-hydroxybutyrylase (EC
2.3.1.a), as previously described. Alternatively,
4-hydroxybutyryl-phosphate can be converted to 4-hydroxybutanal by
4-hydroxybutanal dehydrogenase (phosphorylating) (EC 1.2.1.d).
4-Hydroxybutyryl-CoA can be converted to 4-hydroxybutanal by
4-hydroxybutyryl-CoA reductase (or 4-hydroxybutanal dehydrogenase)
(EC 1.2.1.b), as previously described. 4-Hydroxybutyryl-CoA can be
converted to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase
(alcohol forming) (EC 1.1.1.c). 4-Hydroxybutanal can be converted
to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a), as
previously described.
TABLE-US-00066 TABLE 16 BDO pathway from alpha-ketoglutarate.
Desired Desired GenBank ID Known FIG. EC class substrate product
Enzyme name Gene name (if available) Organism Substrates 8B 4.1.1.a
alpha- succinic alpha-ketoglutarate kgd O50463.4 Mycobacterium
alpha- ketoglutarate semialdehyde decarboxylase tuberculosis
ketoglutarate gadA NP_417974 Escherichia coli glutamate gadB
NP_416010 Escherichia coli glutamate 8B 1.4.1.a alpha- glutamate
glutamate gdhA P00370 Escherichia coli glutamate ketoglutarate
dehydrogenase gdh P96110.4 Thermotoga glutamate maritima gdhA1
NP_279651.1 Halobacterium glutamate salinarum 8B 1.4.1.a
4-aminobutyrate succinic 4-aminobutyrate lysDH AB052732 Geobacillus
lysine semialdehyde oxidoreductase stearothermo- (deaminating)
philus lysDH NP_147035.1 Aeropyrum lysine pernix K1 ldh P0A393
Bacillus cereus leucine, isoleucine, valine, 2- aminobutanoate 8B
2.6.1.a 4-aminobutyrate succinic 4-aminobutyrate gabT P22256.1
Escherichia coli 4- semialdehyde transaminase aminobutyryate puuE
NP_415818.1 Escherichia coli 4- aminobutyryate UGA1 NP_011533.1
Saccharomyces 4- cerevisiae aminobutyryate 8B 4.1.1.a glutamate
4-aminobutyrate glutamate gadA NP_417974 Escherichia coli glutamate
decarboxylase gadB NP_416010 Escherichia coli glutamate kgd
O50463.4 Mycobacterium alpha- tuberculosis ketoglutarate 8B 1.1.1.a
succinate 4- 4-hydroxybutyrate 4hbd YP_726053.1 Ralstonia 4-
semialdehyde hydroxybutyrate dehydrogenase eutropha H16
hydroxybutyrate 4hbd L21902.1 Clostridium 4- kluyveri
hydroxybutyrate DSM 555 4hbd Q94B07 Arabidopsis 4- thaliana
hydroxybutyrate 8B 2.8.3.a 4- 4- 4-hydroxybutyryl- cat1, cat2,
P38946.1, Clostridium succinate, 4- hydroxybutyrate hydroxybutyryl-
CoA transferase cat3 P38942.2, kluyveri hydroxybutyrate, CoA
EDK35586.1 butyrate gctA, gctB CAA57199.1, Acidaminococcus
glutarate CAA57200.1 fermentans atoA, atoD P76459.1, Escherichia
coli butanoate P76458.1 8B 3.1.2.a 4- 4- 4-hydroxybutyryl- tesB
NP_414986 Escherichia coli adipyl-CoA hydroxybutyrate
hydroxybutyryl- CoA hydrolase CoA acot12 NP_570103.1 Rattus
norvegicus butyryl-CoA hibch Q6NVY1.2 Homo sapiens 3- hydroxypro-
panoyl-CoA 8B 6.2.1.a 4- 4- 4-hydroxybutyryl- sucCD NP_415256.1,
Escherichia coli succinate hydroxybutyrate hydroxybutyryl- CoA
ligase (or 4- AAC73823.1 CoA hydroxybutyryl- CoA synthetase) phl
CAJ15517.1 Penicillium phenylacetate chrysogenum bioW NP_390902.2
Bacillus subtilis 6- carboxyhexanoate 8B 2.7.2.a 4- 4-
4-hydroxybutyrate ackA NP_416799.1 Escherichia coli acetate,
hydroxybutyrate hydroxybutyryl- kinase propionate phosphate buk1
NP_349675 Clostridium butyrate acetobutylicum buk2 Q97II1
Clostridium butyrate acetobutylicum 8B 2.3.1.a 4- 4-
phosphotrans-4- ptb NP_349676 Clostridium butyryl- hydroxybutyryl-
hydroxybutyryl- hydroxybutyrylase acetobutylicum phosphate
phosphate CoA ptb AAR19757.1 butyrate- butyryl- producing phosphate
bacterium L2-50 ptb CAC07932.1 Bacillus butyryl- megaterium
phosphate 8B 1.2.1.d 4- 4- 4-hydroxybutanal asd NP_417891.1
Escherichia coli L-4-aspartyl- hydroxybutyryl- hydroxybutanal
dehydrogenase phosphate phosphate (phosphorylating) proA
NP_414778.1 Escherichia coli L-glutamyl-5- phospate gapA P0A9B2.2
Escherichia coli Glyceraldehyde- 3-phosphate 8B 1.2.1.b 4- 4-
4-hydroxybutyryl- sucD P38947.1 Clostridium succinyl-CoA
hydroxybutyryl- hydroxybutanal CoA reductase (or kluyveri CoA
4-hydroxybutanal dehydrogenase) sucD NP_904963.1 Porphyromonas
succinyl-CoA gingivalis Msed_0709 YP_001190808.1 Metallosphaera
malonyl-CoA sedula 8B 1.1.1.c 4- 1,4-butanediol 4-hydroxybutyryl-
adhE2 AAK09379.1 Clostridium butanoyl-CoA hydroxybutyryl- CoA
reductase acetobutylicum CoA (alcohol forming) mcr AAS20429.1
Chloroflexus malonyl-CoA aurantiacus FAR AAD38039.1 Simmondsia long
chain acyl- chinensis CoA 8B 1.1.1.a 4- 1,4-butanediol
1,4-butanediol ADH2 NP_014032.1 Saccharymyces general
hydroxybutanal dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555
Example VII
BDO Pathways from 4-Aminobutyrate
[0423] This example describes exemplary BDO pathways from
4-aminobutyrate.
[0424] FIG. 9A depicts exemplary BDO pathways in which
4-aminobutyrate is converted to BDO. Enzymes of such an exemplary
BDO pathway are listed in Table 17, along with exemplary genes
encoding these enzymes.
[0425] Briefly, 4-aminobutyrate can be converted to
4-aminobutyryl-CoA by 4-aminobutyrate CoA transferase (EC 2.8.3.a),
4-aminobutyryl-CoA hydrolase (EC 3.1.2.a), or 4-aminobutyrate-CoA
ligase (or 4-aminobutyryl-CoA synthetase) (EC 6.2.1.a).
4-aminobutyryl-CoA can be converted to 4-oxobutyryl-CoA by
4-aminobutyryl-CoA oxidoreductase (deaminating) (EC 1.4.1.a) or
4-aminobutyryl-CoA transaminase (EC 2.6.1.a). 4-oxobutyryl-CoA can
be converted to 4-hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA
dehydrogenase (EC 1.1.1.a). 4-hydroxybutyryl-CoA can be converted
to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase (alcohol
forming) (EC 1.1.1.c). Alternatively, 4-hydroxybutyryl-CoA can be
converted to 4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or
4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4-hydroxybutanal can
be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC
1.1.1.a).
TABLE-US-00067 TABLE 17 BDO pathway from 4-aminobutyrate. Desired
Desired GenBank ID Known FIG. EC class substrate product Enzyme
name Gene name (if available) Organism Substrates 9A 2.8.3.a 4- 4-
4-aminobutyrate cat1, cat2, P38946.1, Clostridium succinate, 4-
aminobutyrate aminobutyryl- CoA transferase cat3 P38942.2, kluyveri
hydroxybutyrate, CoA EDK35586.1 butyrate gctA, gctB CAA57199.1,
Acidaminococcus glutarate CAA57200.1 fermentans atoA, atoD
P76459.1, Escherichia coli butanoate P76458.1 9A 3.1.2.a 4- 4-
4-aminobutyryl- tesB NP_414986 Escherichia coli adipyl-CoA
aminobutyrate aminobutyryl- CoA hydrolase CoA acot12 NP_570103.1
Rattus norvegicus butyryl-CoA hibch Q6NVY1.2 Homo sapiens 3-
hydroxypropanoyl- CoA 9A 6.2.1.a 4- 4- 4-aminobutyrate- sucCD
NP_415256.1, Escherichia coli succinate aminobutyrate aminobutyryl-
CoA ligase (or 4- AAC73823.1 CoA aminobutyryl- CoA synthetase) phl
CAJ15517.1 Penicillium phenylacetate chrysogenum bioW NP_390902.2
Bacillus subtilis 6- carboxyhexanoate 9A 1.4.1.a 4- 4-oxobutyryl-
4-aminobutyryl- lysDH AB052732 Geobacillus lysine aminobutyryl- CoA
CoA stearothermophilus CoA oxidoreductase (deaminating) lysDH
NP_147035.1 Aeropyrum lysine pernix K1 ldh P0A393 Bacillus cereus
leucine, isoleucine, valine, 2- aminobutanoate 9A 2.6.1.a 4-
4-oxobutyryl- 4-aminobutyryl- gabT P22256.1 Escherichia coli
4-aminobutyryate aminobutyryl- CoA CoA transaminase CoA abat
P50554.3 Rattus norvegicus 3-amino-2- methylpropionate SkyPYD4
ABF58893.1 Saccharomyces beta-alanine 9A 1.1.1.a 4-oxobutyryl- 4-
4-hydroxybutyryl- ADH2 NP_014032.1 kluyveri general CoA hydroxy-
CoA Saccharymyces butyryl- dehydrogenase cerevisiae CoA yqhD
NP_417484.1 Escherichia coli >C3 4hbd L21902.1 Clostridium
Succinate kluyveri semialdehyde DSM 555 8 1.1.1.c 4- 1,4-butanediol
4-hydroxybutyryl- adhE2 AAK09379.1 Clostridium butanoyl-CoA
hydroxybutyryl- CoA reductase acetobutylicum CoA (alcohol forming)
mcr AAS20429.1 Chloroflexus malonyl-CoA aurantiacus FAR AAD38039.1
Simmondsia long chain acyl- chinensis CoA 8 1.2.1.b 4- 4-
4-hydroxybutyryl- sucD P38947.1 Clostridium Succinyl-CoA
hydroxybutyryl- hydroxybutanal CoA reductase (or kluyveri CoA
4-hydroxybutanal dehydrogenase) sucD NP_904963.1 Porphyromonas
Succinyl-CoA gingivalis Msed_0709 YP_001190808.1 Metallosphaera
Malonyl-CoA sedula 8 1.1.1.a 4- 1,4-butanediol 1,4-butanediol ADH2
NP_014032.1 Saccharymyces general hydroxybutanal dehydrogenase
cerevisiae yqhD NP_417484.1 Escherichia coli >C3 4hbd L21902.1
Clostridium Succinate kluyveri semialdehyde DSM 555
[0426] Enzymes for another exemplary BDO pathway converting
4-aminobutyrate to BDO is shown in FIG. 9A. Enzymes of such an
exemplary BDO pathway are listed in Table 18, along with exemplary
genes encoding these enzymes.
[0427] Briefly, 4-aminobutyrate can be converted to
4-aminobutyryl-CoA by 4-aminobutyrate CoA transferase (EC 2.8.3.a),
4-aminobutyryl-CoA hydrolase (EC 3.1.2.a) or 4-aminobutyrate-CoA
ligase (or 4-aminobutyryl-CoA synthetase) (EC 6.2.1.a).
4-aminobutyryl-CoA can be converted to 4-aminobutan-1-ol by
4-aminobutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c).
Alternatively, 4-aminobutyryl-CoA can be converted to
4-aminobutanal by 4-aminobutyryl-CoA reductase (or 4-aminobutanal
dehydrogenase) (EC 1.2.1.b), and 4-aminobutanal converted to
4-aminobutan-1-ol by 4-aminobutan-1-ol dehydrogenase (EC 1.1.1.a).
4-aminobutan-1-ol can be converted to 4-hydroxybutanal by
4-aminobutan-1-ol oxidoreductase (deaminating) (EC 1.4.1.a) or
4-aminobutan-1-ol transaminase (EC 2.6.1.a). 4-hydroxybutanal can
be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC
1.1.1.a).
TABLE-US-00068 TABLE 18 BDO pathway from 4-aminobutyrate. Desired
Desired GenBank ID (if Known FIG. EC class substrate product Enzyme
name Gene name available) Organism Substrate 9A 2.8.3.a 4- 4-
4-aminobutyrate CoA cat1, cat2, P38946.1, Clostridium kluyveri
succinate, 4- aminobutyrate aminobutyryl- transferase cat3
P38942.2, hydroxybutyrate, CoA EDK35586.1 butyrate gctA, gctB
CAA57199.1, Acidaminococcus glutarate CAA57200.1 fermentans atoA,
atoD P76459.1, Escherichia coli butanoate P76458.1 9A 3.1.2.a 4- 4-
4-aminobutyryl-CoA tesB NP_414986 Escherichia coli adipyl-CoA
aminobutyrate aminobutyryl- hydrolase CoA acot12 NP_570103.1 Rattus
norvegicus butyryl-CoA hibch Q6NVY1.2 Homo sapiens 3-hydroxy-
propanoyl- CoA 9A 6.2.1.a 4- 4- 4-aminobutyrate-CoA sucCD
NP_415256.1, Escherichia coli succinate aminobutyrate aminobutyryl-
ligase (or 4- AAC73823.1 CoA aminobutyryl-CoA synthetase) phl
CAJ15517.1 Penicillium phenylacetate chrysogenum bioW NP_390902.2
Bacillus subtilis 6- carboxyhexanoate 9A 1.1.1.c 4- 4-aminobutan-
4-aminobutyryl-CoA adhE2 AAK09379.1 Clostridium butanoyl-CoA
aminobutyryl- 1-ol reductase (alcohol acetobutylicum CoA forming)
mcr AAS20429.1 Chloroflexus malonyl-CoA aurantiacus FAR AAD38039.1
Simmondsia long chain chinensis acyl-CoA 9A 1.2.1.b 4-
4-aminobutanal 4-aminobutyryl-CoA sucD P38947.1 Clostridium
kluyveri Succinyl-CoA aminobutyryl- reductase (or 4- CoA
aminobutanal dehydrogenase) sucD NP_904963.1 Porphyromonas
Succinyl-CoA gingivalis Msed_0709 YP_001190808.1 Metallosphaera
Malonyl-CoA sedula 9A 1.1.1.a 4-aminobutanal 4-aminobutan-
4-aminobutan-1-ol ADH2 NP_014032.1 Saccharymyces general 1-ol
dehydrogenase cerevisiae yqhD NP_417484.1 Escherichia coli >C3
4hbd L21902.1 Clostridium kluyveri Succinate DSM 555 semialdehyde
9A 1.4.1.a 4-aminobutan- 4- 4-aminobutan-1-ol lysDH AB052732
Geobacillus lysine 1-ol hydroxybutanal oxidoreductase
stearothermophilus (deaminating) lysDH NP_147035.1 Aeropyrum pernix
lysine K1 ldh P0A393 Bacillus cereus leucine, isoleucine, valine,
2- aminobutanoate 9A 2.6.1.a 4-aminobutan- 4- 4-aminobutan-1-ol
gabT P22256.1 Escherichia coli 4- 1-ol hydroxybutanal transaminase
aminobutyryate abat P50554.3 Rattus norvegicus 3-amino-2-
methylpropionate SkyPYD4 ABF58893.1 Saccharomyces beta-alanine
kluyveri 9A 1.1.1.a 4- 1,4-butanediol 1,4-butanediol ADH2
NP_014032.1 Saccharymyces general hydroxybutanal dehydrogenase
cerevisiae yqhD NP_417484.1 Escherichia coli >C3 4hbd L21902.1
Clostridium kluyveri Succinate DSM 555 semialdehyde
[0428] FIG. 9B depicts exemplary BDO pathway in which
4-aminobutyrate is converted to BDO. Enzymes of such an exemplary
BDO pathway are listed in Table 19, along with exemplary genes
encoding these enzymes.
[0429] Briefly, 4-aminobutyrate can be converted to
[(4-aminobutanolyl)oxy] phosphonic acid by 4-aminobutyrate kinase
(EC 2.7.2.a). [(4-aminobutanolyl)oxy] phosphonic acid can be
converted to 4-aminobutanal by 4-aminobutyraldehyde dehydrogenase
(phosphorylating) (EC 1.2.1.d). 4-aminobutanal can be converted to
4-aminobutan-1-ol by 4-aminobutan-1-ol dehydrogenase (EC 1.1.1.a).
4-aminobutan-1-ol can be converted to 4-hydroxybutanal by
4-aminobutan-1-ol oxidoreductase (deaminating) (EC 1.4.1.a) or
4-aminobutan-1-ol transaminase (EC 2.6.1.a). Alternatively,
[(4-aminobutanolyl)oxy] phosphonic acid can be converted to
[(4-oxobutanoyl)oxy] phosphonic acid by
[(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating)
(EC 1.4.1.a) or [(4-aminobutanolyl)oxy]phosphonic acid transaminase
(EC 2.6.1.a). [(4-oxobutanoyl)oxy] phosphonic acid can be converted
to 4-hydroxybutyryl-phosphate by 4-hydroxybutyryl-phosphate
dehydrogenase (EC 1.1.1.a). 4-hydroxybutyryl-phosphate can be
converted to 4-hydroxybutanal by 4-hydroxybutyraldehyde
dehydrogenase (phosphorylating) (EC 1.2.1.d). 4-hydroxybutanal can
be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC
1.1.1.a).
TABLE-US-00069 TABLE 19 BDO pathway from 4-aminobutyrate. Desired
Desired Gene GenBank ID Known FIG. EC class substrate product
Enzyme name name (if available) Organism Substrate 9B 2.7.2.a 4-
[(4- 4- ackA NP_416799.1 Escherichia coli acetate, aminobutyrate
aminobutanolyl) aminobutyrate propionate oxy] kinase phosphonic
acid buk1 NP_349675 Clostridium butyrate acetobutylicum proB
NP_414777.1 Escherichia coli glutamate 9B 1.2.1.d [(4- 4- 4- asd
NP_417891.1 Escherichia coli L-4-aspartyl- aminobutanolyl)
aminobutanal aminobutyraldehyde phosphate oxy] dehydrogenase
phosphonic (phosphorylating) acid proA NP_414778.1 Escherichia coli
L-glutamyl-5- phospate gapA P0A9B2.2 Escherichia coli
Glyceraldehyde-3- phosphate 9B 1.1.1.a 4-aminobutanal 4-aminobutan-
4-aminobutan- ADH2 NP_014032.1 Saccharymyces general 1-ol 1-ol
cerevisiae dehydrogenase yqhD NP_417484.1 Escherichia coli >C3
4hbd L21902.1 Clostridium kluyveri Succinate DSM 555 semialdehyde
9B 1.4.1.a 4-aminobutan- 4- 4-aminobutan- lysDH AB052732
Geobacillus lysine 1-ol hydroxybutanal 1-ol stearothermophilus
oxidoreductase (deaminating) lysDH NP_147035.1 Aeropyrum pernix
lysine K1 ldh P0A393 Bacillus cereus leucine, isoleucine, valine,
2-aminobutanoate 9B 2.6.1.a 4-aminobutan- 4- 4-aminobutan- gabT
P22256.1 Escherichia coli 4-aminobutyryate 1-ol hydroxybutanal 1-ol
transaminase abat P50554.3 Rattus norvegicus 3-amino-2-
methylpropionate SkyPYD4 ABF58893.1 Saccharomyces beta-alanine
kluyveri 9B 1.4.1.a [(4- [(4- [(4- lysDH AB052732 Geobacillus
lysine aminobutanolyl) oxobutanolyl) aminobutanolyl)
stearothermophilus oxy] oxy] oxy]phosphonic phosphonic phosphonic
acid acid acid oxidoreductase (deaminating) lysDH NP_147035.1
Aeropyrum pernix lysine K1 ldh P0A393 Bacillus cereus leucine,
isoleucine, valine, 2-aminobutanoate 9B 2.6.1.a [(4- [(4- [(4- gabT
P22256.1 Escherichia coli 4-aminobutyryate aminobutanolyl)
oxobutanolyl) aminobutanolyl) oxy] oxy] oxy]phosphonic phosphonic
phosphonic acid acid acid transaminase SkyPYD4 ABF58893.1
Saccharomyces beta-alanine kluyveri serC NP_415427.1 Escherichia
coli phosphoserine, phospho- hydroxythreonine 9B 1.1.1.a [(4- 4- 4-
ADH2 NP_014032.1 Saccharymyces general oxobutanolyl)
hydroxybutyryl- hydroxybutyryl- cerevisiae oxy] phosphate phosphate
phosphonic dehydrogenase acid yqhD NP_417484.1 Escherichia coli
>C3 4hbd L21902.1 Clostridium kluyveri Succinate DSM 555
semialdehyde 9B 1.2.1.d 4- 4- 4- asd NP_417891.1 Escherichia coli
L-4-aspartyl- hydroxybutyryl- hydroxybutanal hydroxy- phosphate
phosphate butyraldehyde dehydrogenase (phosphorylating) proA
NP_414778.1 Escherichia coli L-glutamyl-5- phospate gapA P0A9B2.2
Escherichia coli Glyceraldehyde- 3-phosphate 9B 1.1.1.a 4-
1,4-butanediol 1,4-butanediol ADH2 NP_014032.1 Saccharymyces
general hydroxybutanal dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium kluyveri
Succinate DSM 555 semialdehyde
[0430] FIG. 9C shows an exemplary pathway through acetoacetate.
Example VIII
Exemplary BDO Pathways from Alpha-Ketoglutarate
[0431] This example describes exemplary BDO pathways from
alpha-ketoglutarate.
[0432] FIG. 10 depicts exemplary BDO pathways in which
alpha-ketoglutarate is converted to BDO. Enzymes of such an
exemplary BDO pathway are listed in Table 20, along with exemplary
genes encoding these enzymes.
[0433] Briefly, alpha-ketoglutarate can be converted to
alpha-ketoglutaryl-phosphate by alpha-ketoglutarate 5-kinase (EC
2.7.2.a). Alpha-ketoglutaryl-phosphate can be converted to
2,5-dioxopentanoic acid by 2,5-dioxopentanoic semialdehyde
dehydrogenase (phosphorylating) (EC 1.2.1.d). 2,5-dioxopentanoic
acid can be converted to 5-hydroxy-2-oxopentanoic acid by
2,5-dioxopentanoic acid reductase (EC 1.1.1.a). Alternatively,
alpha-ketoglutarate can be converted to alpha-ketoglutaryl-CoA by
alpha-ketoglutarate CoA transferase (EC 2.8.3.a),
alpha-ketoglutaryl-CoA hydrolase (EC 3.1.2.a) or
alpha-ketoglutaryl-CoA ligase (or alpha-ketoglutaryl-CoA
synthetase) (EC 6.2.1.a). Alpha-ketoglutaryl-CoA can be converted
to 2,5-dioxopentanoic acid by alpha-ketoglutaryl-CoA reductase (or
2,5-dioxopentanoic acid dehydrogenase) (EC 1.2.1.b).
2,5-Dioxopentanoic acid can be converted to
5-hydroxy-2-oxopentanoic acid by 5-hydroxy-2-oxopentanoic acid
dehydrogenase. Alternatively, alpha-ketoglutaryl-CoA can be
converted to 5-hydroxy-2-oxopentanoic acid by
alpha-ketoglutaryl-CoA reductase (alcohol forming) (EC 1.1.1.c).
5-hydroxy-2-oxopentanoic acid can be converted to 4-hydroxybutanal
by 5-hydroxy-2-oxopentanoic acid decarboxylase (EC 4.1.1.a).
4-hydroxybutanal can be converted to 1,4-butanediol by
1,4-butanediol dehydrogenase (EC 1.1.1.a). 5-hydroxy-2-oxopentanoic
acid can be converted to 4-hydroxybutyryl-CoA by
5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation) (EC
1.2.1.c).
TABLE-US-00070 TABLE 20 BDO pathway from alpha-ketoglutarate.
Desired Desired Gene GenBank ID FIG. EC class substrate product
Enzyme name name (if available) Organism Known Substrate 10 2.7.2.a
alpha- alpha- alpha- ackA NP_416799.1 Escherichia coli acetate,
propionate ketoglutarate ketoglutaryl- ketoglutarate 5- phosphate
kinase buk1 NP_349675 Clostridium butyrate acetobutylicum proB
NP_414777.1 Escherichia coli glutamate 10 1.2.1.d alpha- 2,5- 2,5-
proA NP_414778.1 Escherichia coli L-glutamyl- ketoglutaryl-
dioxopentanoic dioxopentanoic 5-phospate phosphate acid
semialdehyde dehydrogenase (phosphorylating) asd NP_417891.1
Escherichia coli L-4-aspartyl- phosphate gapA P0A9B2.2 Escherichia
coli Glyceraldehyde- 3-phosphate 10 1.1.1.a 2,5- 5-hydroxy-2- 2,5-
ADH2 NP_014032.1 Saccharymyces general dioxopentanoic oxopentanoic
dioxopentanoic cerevisiae acid acid acid reductase yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555 10 2.8.3.a alpha- alpha- alpha- cat1,
cat2, P38946.1, Clostridium succinate, ketoglutarate ketoglutaryl-
ketoglutarate cat3 P38942.2, kluyveri 4-hydroxybutyrate, CoA CoA
EDK35586.1 butyrate transferase gctA, gctB CAA57199.1,
Acidaminococcus glutarate CAA57200.1 fermentans atoA, atoD
P76459.1, Escherichia coli butanoate P76458.1 10 3.1.2.a alpha-
alpha- alpha- tesB NP_414986 Escherichia coli adipyl-CoA
ketoglutarate ketoglutaryl- ketoglutaryl- CoA CoA hydrolase acot12
NP_570103.1 Rattus norvegicus butyryl-CoA hibch Q6NVY1.2 Homo
sapiens 3-hydroxy- propanoyl-CoA 10 6.2.1.a alpha- alpha- alpha-
sucCD NP_415256.1, Escherichia coli succinate ketoglutarate
ketoglutaryl- ketoglutaryl- AAC73823.1 CoA CoA ligase (or alpha-
ketoglutaryl- CoA synthetase) phl CAJ15517.1 Penicillium
phenylacetate chrysogenum bioW NP_390902.2 Bacillus 6-carboxy-
subtilis hexanoate 10 1.2.1.b alpha- 2,5- alpha- sucD P38947.1
Clostridium Succinyl-CoA ketoglutaryl- dioxopentanoic ketoglutaryl-
kluyveri CoA acid CoA reductase (or 2,5- dioxopentanoic acid
dehydrogenase) Msed_0709 YP_001190808.1 Metallosphaera Malonyl-CoA
sedula bphG BAA03892.1 Pseudomonas sp Acetaldehyde,
Propionaldehyde, Butyraldehyde, Isobutyraldehyde and Formaldehyde
10 1.1.1.a 2,5- 5-hydroxy-2- 5-hydroxy-2- ADH2 NP_014032.1
Saccharymyces general dioxopentanoic oxopentanoic oxopentanoic yqhD
NP_417484.1 cerevisiae >C3 acid acid acid 4hbd L21902.1
Escherichia coli Succinate dehydrogenase Clostridium semialdehyde
kluyveri DSM 555 10 1.1.1.c alpha- 5-hydroxy-2- alpha- adhE2
AAK09379.1 Clostridium butanoyl- ketoglutaryl- oxopentanoic
ketoglutaryl- acetobutylicum CoA CoA acid CoA reductase (alcohol
forming) mcr AAS20429.1 Chloroflexus malonyl-CoA aurantiacus FAR
AAD38039.1 Simmondsia long chain chinensis acyl-CoA 10 4.1.1.a
5-hydroxy-2- 4- 5-hydroxy-2- pdc P06672.1 Zymomonas mobilus
2-oxopentanoic oxopentanoic hydroxybutanal oxopentanoic acid acid
acid decarboxylase mdlC P20906.2 Pseudomonas 2-oxopentanoic putida
acid pdc1 P06169 Saccharomyces pyruvate cerevisiae 10 1.1.1.a 4-
1,4-butanediol 1,4-butanediol ADH2 NP_014032.1 Saccharomyces
general hydroxybutanal dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555 10 1.2.1.c 5-hydroxy-2- 4-
5-hydroxy-2- sucA, sucB, NP_415254.1, Escherichia coli Alpha-
oxopentanoic hydroxybutyryl- oxopentanoic lpd NP_415255.1,
ketoglutarate acid CoA acid NP_414658.1 dehydrogenase
(decarboxylation) bfmBB, NP_390283.1, Bacillus subtilis 2-keto
acids bfmBAA, NP_390285.1, derivatives of bfmBAB, NP_390284.1,
valine, leucine bfmBAB, P21880.1 and isoleucine pdhD Bckdha,
NP_036914.1, Rattus norvegicus 2-keto acids Bckdhb, NP_062140.1,
derivatives of Dbt, Dld NP_445764.1, valine, leucine NP_955417.1
and isoleucine
Example IX
Exemplary BDO Pathways from Glutamate
[0434] This example describes exemplary BDO pathways from
glutamate.
[0435] FIG. 11 depicts exemplary BDO pathways in which glutamate is
converted to BDO. Enzymes of such an exemplary BDO pathway are
listed in Table 21, along with exemplary genes encoding these
enzymes.
[0436] Briefly, glutamate can be converted to glutamyl-CoA by
glutamate CoA transferase (EC 2.8.3.a), glutamyl-CoA hydrolase (EC
3.1.2.a) or glutamyl-CoA ligase (or glutamyl-CoA synthetase) (EC
6.2.1.a). Alternatively, glutamate can be converted to
glutamate-5-phosphate by glutamate 5-kinase (EC 2.7.2.a).
Glutamate-5-phosphate can be converted to glutamate-5-semialdehyde
by glutamate-5-semialdehyde dehydrogenase (phosphorylating) (EC
1.2.1.d). Glutamyl-CoA can be converted to glutamate-5-semialdehyde
by glutamyl-CoA reductase (or glutamate-5-semialdehyde
dehydrogenase) (EC 1.2.1.b). Glutamate-5-semialdehyde can be
converted to 2-amino-5-hydroxypentanoic acid by
glutamate-5-semialdehyde reductase (EC 1.1.1.a). Alternatively,
glutamyl-CoA can be converted to 2-amino-5-hydroxypentanoic acid by
glutamyl-CoA reductase (alcohol forming) (EC 1.1.1.c).
2-Amino-5-hydroxypentanoic acid can be converted to
5-hydroxy-2-oxopentanoic acid by 2-amino-5-hydroxypentanoic acid
oxidoreductase (deaminating) (EC 1.4.1.a) or
2-amino-5-hydroxypentanoic acid transaminase (EC 2.6.1.a).
5-Hydroxy-2-oxopentanoic acid can be converted to 4-hydroxybutanal
by 5-hydroxy-2-oxopentanoic acid decarboxylase (EC 4.1.1.a).
4-Hydroxybutanal can be converted to 1,4-butanediol by
1,4-butanediol dehydrogenase (EC 1.1.1.a). Alternatively,
5-hydroxy-2-oxopentanoic acid can be converted to
4-hydroxybutyryl-CoA by 5-hydroxy-2-oxopentanoic acid dehydrogenase
(decarboxylation) (EC 1.2.1.c).
TABLE-US-00071 TABLE 21 BDO pathway from glutamate. Desired Desired
GenBank ID (if FIG. EC class substrate product Enzyme name Gene
name available) Organism Known Substrate 11 2.8.3.a glutamate
glutamyl-CoA glutamate CoA cat1, cat2, P38946.1, Clostridium
succinate, 4- transferase cat3 P38942.2, kluyveri hydroxybutyrate,
EDK35586.1 butyrate gctA, gctB CAA57199.1, Acidaminococcus
glutarate CAA57200.1 fermentans atoA, atoD P76459.1, Escherichia
coli butanoate P76458.1 11 3.1.2.a glutamate glutamyl-CoA
glutamyl-CoA tesB NP_414986 Escherichia coli adipyl-CoA hydrolase
acot12 NP_570103.1 Rattus norvegicus butyryl-CoA hibch Q6NVY1.2
Homo sapiens 3-hydrox- ypropanoyl- CoA 11 6.2.1.a glutamate
glutamyl-CoA glutamyl-CoA sucCD NP_415256.1, Escherichia coli
succinate ligase (or AAC73823.1 glutamyl- CoA synthetase) phl
CAJ15517.1 Penicillium phenylacetate chrysogenum bioW NP_390902.2
Bacillus subtilis 6-carboxy- hexanoate 11 2.7.2.a glutamate
glutamate-5- glutamate ackA NP_416799.1 Escherichia coli acetate,
phosphate 5-kinase propionate buk1 NP_349675 Clostridium butyrate
acetobutylicum proB NP_414777.1 Escherichia coli glutamate 11
1.2.1.d glutamate-5- glutamate-5- glutamate-5- proA NP_414778.1
Escherichia coli L-glutamyl-5- phosphate semialdehyde semialdehyde
phospate dehydrogenase (phosphorylating) asd NP_417891.1
Escherichia coli L-4-aspartyl- phosphate gapA P0A9B2.2 Escherichia
coli Glyceraldehyde- 3-phosphate 11 1.2.1.b glutamyl-CoA
glutamate-5- glutamyl-CoA sucD P38947.1 Clostridium Succinyl-CoA
semialdehyde reductase (or kluyveri glutamate-5- semialdehyde
dehydrogenase) Msed_0709 YP_001190808.1 Metallosphaera Malonyl-CoA
sedula bphG BAA03892.1 Pseudomonas sp Acetaldehyde,
Propionaldehyde, Butyraldehyde, Isobutyraldehyde and Formaldehyde
11 1.1.1.a glutamate-5- 2-amino-5- glutamate-5- ADH2 NP_014032.1
Saccharymyces general semialdehyde hydroxypentanoic semialdehyde
cerevisiae acid reductase yqhD NP_417484.1 Escherichia coli >C3
4hbd L21902.1 Clostridium Succinate kluyveri semialdehyde DSM 555
11 1.1.1.c glutamyl-CoA 2-amino-5- glutamyl-CoA adhE2 AAK09379.1
Clostridium butanoyl-CoA hydroxypentanoic reductase (alcohol
acetobutylicum acid forming) mcr AAS20429.1 Chloroflexus
malonyl-CoA aurantiacus FAR AAD38039.1 Simmondsia long chain
chinensis acyl-CoA 11 1.4.1.a 2-amino-5- 5-hydroxy-2- 2-amino-5-
gdhA P00370 Escherichia coli glutamate hydroxypentanoic
oxopentanoic hydroxypentanoic acid acid acid oxidoreductase
(deaminating) ldh P0A393 Bacillus cereus leucine, isoleucine,
valine, 2- aminobutanoate nadX NP_229443.1 Thermotoga aspartate
maritima 11 2.6.1.a 2-amino-5- 5-hydroxy-2- 2-amino-5- aspC
NP_415448.1 Escherichia coli aspartate hydroxypentanoic
oxopentanoic hydroxypentanoic acid acid acid transaminase AAT2
P23542.3 Saccharomyces aspartate cerevisiae avtA YP_026231.1
Escherichia coli valine, alpha- aminobutyrate 11 4.1.1.a
5-hydroxy-2- 4- 5-hydroxy-2- pdc P06672.1 Zymomonas 2-oxopentanoic
oxopentanoic hydroxybutanal oxopentanoic acid mobilus acid acid
decarboxylase mdlC P20906.2 Pseudomonas 2-oxopentanoic putida acid
pdc1 P06169 Saccharomyces pyruvate cerevisiae 11 1.1.1.a 4-
1,4-butanediol 1,4-butanediol ADH2 NP_014032.1 Saccharymyces
general hydroxybutanal dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555 11 1.2.1.c 5-hydroxy-2- 4-
5-hydroxy-2- sucA, sucB, NP_415254.1, Escherichia coli Alpha-
oxopentanoic hydroxybutyryl- oxopentanoic acid lpd NP_415255.1,
ketoglutarate acid CoA dehydrogenase NP_414658.1 (decarboxylation)
bfmBB, NP_390283.1, Bacillus subtilis 2-keto acids bfmBAA,
NP_390285.1, derivatives bfmBAB, NP_390284.1, of valine, bfmBAB,
P21880.1 leucine and pdhD isoleucine Bckdha, NP_036914.1, Rattus
norvegicus 2-keto acids Bckdhb, NP_062140.1, derivatives Dbt, Dld
NP_445764.1, of valine, NP_955417.1 leucine and isoleucine
Example X
Exemplary BDO from Acetoacetyl-CoA
[0437] This example describes an exemplary BDO pathway from
acetoacetyl-CoA.
[0438] FIG. 12 depicts exemplary BDO pathways in which
acetoacetyl-CoA is converted to BDO. Enzymes of such an exemplary
BDO pathway are listed in Table 22, along with exemplary genes
encoding these enzymes.
[0439] Briefly, acetoacetyl-CoA can be converted to
3-hydroxybutyryl-CoA by 3-hydroxybutyryl-CoA dehydrogenase (EC
1.1.1.a). 3-Hydroxybutyryl-CoA can be converted to crotonoyl-CoA by
3-hydroxybutyryl-CoA dehydratase (EC 4.2.1.a). Crotonoyl-CoA can be
converted to vinylacetyl-CoA by vinylacetyl-CoA .DELTA.-isomerase
(EC 5.3.3.3). Vinylacetyl-CoA can be converted to
4-hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA dehydratase (EC
4.2.1.a). 4-Hydroxybutyryl-CoA can be converted to 1,4-butanediol
by 4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c).
Alternatively, 4-hydroxybutyryl-CoA can be converted to
4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or
4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4-Hydroxybutanal can
be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC
1.1.1.a).
TABLE-US-00072 TABLE 22 BDO pathway from acetoacetyl-CoA. Desired
Desired GenBank ID FIG. EC class substrate product Enzyme name Gene
name (if available) Organism Known Substrate 12 1.1.1.a
acetoacetyl- 3- 3-hydroxybutyryl- hbd NP_349314.1 Clostridium
3-hydroxybutyryl- CoA hydroxybutyryl- CoA dehydrogenase
acetobutylicum CoA CoA hbd AAM14586.1 Clostridium 3-hydroxybutyryl-
beijerinckii CoA Msed_1423 YP_001191505 Metallosphaera presumed 3-
sedula hydroxybutyryl- CoA 12 4.2.1.a 3- crotonoyl-
3-hydroxybutyryl- crt NP_349318.1 Clostridium 3-hydroxybutyryl-
hydroxybutyryl- CoA CoA dehydratase acetobutylicum CoA CoA maoC
NP_415905.1 Escherichia coli 3-hydroxybutyryl- CoA paaF NP_415911.1
Escherichia coli 3-hydroxyadipyl- CoA 12 5.3.3.3 crotonoyl-CoA
vinylacetyl- vinylacetyl-CoA .DELTA.- abfD YP_001396399.1
Clostridium 4-hydroxybutyryl- CoA isomerase kluyveri CoA DSM 555
abfD P55792 Clostridium 4-hydroxybutyryl- aminobutyricum CoA abfD
YP_001928843 Porphyromonas 4-hydroxybutyryl- gingivalis CoA ATCC
33277 12 4.2.1.a vinylacetyl- 4- 4-hydroxybutyryl- abfD
YP_001396399.1 Clostridium 4-hydroxybutyryl- CoA hydroxybutyryl-
CoA dehydratase kluyveri CoA CoA DSM 555 abfD P55792 Clostridium
4-hydroxybutyryl- aminobutyricum CoA abfD YP_001928843
Porphyromonas 4-hydroxybutyryl- gingivalis ATCC 33277 CoA 12
1.1.1.c 4- 1,4- 4-hydroxybutyryl- adhE2 AAK09379.1 Clostridium
butanoyl-CoA hydroxybutyryl- butanediol CoA reductase
acetobutylicum CoA (alcohol forming) mcr AAS20429.1 Chloroflexus
malonyl-CoA aurantiacus FAR AAD38039.1 Simmondsia long chain
chinensis acyl-CoA 12 1.2.1.b 4- 4- 4-hydroxybutyryl- sucD P38947.1
Clostridium Succinyl-CoA hydroxybutyryl- hydroxybutanal CoA
reductase (or kluyveri CoA 4-hydroxybutanal dehydrogenase) sucD
NP_904963.1 Porphyromonas Succinyl-CoA gingivalis Msed_0709
YP_001190808.1 Metallosphaera Malonyl-CoA sedula 12 1.1.1.a 4- 1,4-
1,4-butanediol ADH2 NP_014032.1 Saccharymyces general
hydroxybutanal butanediol dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555
Example XI
Exemplary BDO Pathway from Homoserine
[0440] This example describes an exemplary BDO pathway from
homoserine.
[0441] FIG. 13 depicts exemplary BDO pathways in which homoserine
is converted to BDO. Enzymes of such an exemplary BDO pathway are
listed in Table 23, along with exemplary genes encoding these
enzymes.
[0442] Briefly, homoserine can be converted to
4-hydroxybut-2-enoate by homoserine deaminase (EC 4.3.1.a).
Alternatively, homoserine can be converted to homoserine-CoA by
homoserine CoA transferase (EC 2.8.3.a), homoserine-CoA hydrolase
(EC 3.1.2.a) or homoserine-CoA ligase (or homoserine-CoA
synthetase) (EC 6.2.1.a). Homoserine-CoA can be converted to
4-hydroxybut-2-enoyl-CoA by homoserine-CoA deaminase (EC 4.3.1.a).
4-Hydroxybut-2-enoate can be converted to 4-hydroxybut-2-enoyl-CoA
by 4-hydroxybut-2-enoyl-CoA transferase (EC 2.8.3.a),
4-hydroxybut-2-enoyl-CoA hydrolase (EC 3.1.2.a), or
4-hydroxybut-2-enoyl-CoA ligase (or 4-hydroxybut-2-enoyl-CoA
synthetase) (EC 6.2.1.a). Alternatively, 4-hydroxybut-2-enoate can
be converted to 4-hydroxybutyrate by 4-hydroxybut-2-enoate
reductase (EC 1.3.1.a). 4-Hydroxybutyrate can be converted to
4-hydroxybutyryl-coA by 4-hydroxybutyryl-CoA transferase (EC
2.8.3.a), 4-hydroxybutyryl-CoA hydrolase (EC 3.1.2.a), or
4-hydroxybutyryl-CoA ligase (or 4-hydroxybutyryl-CoA synthetase)
(EC 6.2.1.a). 4-Hydroxybut-2-enoyl-CoA can be converted to
4-hydroxybutyryl-CoA by 4-hydroxybut-2-enoyl-CoA reductase (EC
1.3.1.a). 4-Hydroxybutyryl-CoA can be converted to 1,4-butanediol
by 4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c).
Alternatively, 4-hydroxybutyryl-CoA can be converted to
4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or
4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4-Hydroxybutanal can
be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC
1.1.1.a).
TABLE-US-00073 TABLE 23 BDO pathway from homoserine. Desired
Desired GenBank ID Known FIG. EC class substrate product Enzyme
name Gene name (if available) Organism Substrate 13 4.3.1.a
homoserine 4-hydroxybut-2- homoserine aspA NP_418562 Escherichia
coli aspartate enoate deaminase aspA P44324.1 Haemophilus aspartate
influenzae aspA P07346 Pseudomonas aspartate fluorescens 13 2.8.3.a
homoserine homoserine- homoserine CoA cat1, cat2, P38946.1,
Clostridium succinate, 4- CoA transferase cat3 P38942.2, kluyveri
hydroxybutyrate, EDK35586.1 butyrate gctA, gctB CAA57199.1,
Acidaminococcus glutarate CAA57200.1 fermentans atoA, atoD
P76459.1, Escherichia coli butanoate P76458.1 13 3.1.2.a homoserine
homoserine- homoserine-CoA tesB NP_414986 Escherichia coli
adipyl-CoA CoA hydrolase acot12 NP_570103.1 Rattus norvegicus
butyryl-CoA hibch Q6NVY1.2 Homo sapiens 3- hydroxy- propanoyl- CoA
13 6.2.1.a homoserine homoserine- homoserine-CoA sucCD NP_415256.1,
Escherichia coli succinate CoA ligase (or AAC73823.1 homoserine-CoA
synthetase) phl CAJ15517.1 Penicillium phenylacetate chrysogenum
bioW NP_390902.2 Bacillus subtilis 6- carboxyhexanoate 13 4.3.1.a
homoserine- 4-hydroxybut-2- homoserine-CoA acl1 CAG29274.1
Clostridium beta-alanyl-CoA CoA enoyl-CoA deaminase propionicum
acl2 CAG29275.1 Clostridium beta-alanyl-CoA propionicum MXAN_4385
YP_632558.1 Myxococcus beta-alanyl-CoA xanthus 13 2.8.3.a
4-hydroxybut- 4-hydroxybut-2- 4-hydroxybut-2- cat1, cat2, P38946.1,
Clostridium succinate, 4- 2-enoate enoyl-CoA enoyl-CoA cat3
P38942.2, kluyveri hydroxybutyrate, transferase EDK35586.1 butyrate
gctA, gctB CAA57199.1, Acidaminococcus glutarate CAA57200.1
fermentans atoA, atoD P76459.1, Escherichia coli butanoate P76458.1
13 3.1.2.a 4-hydroxybut- 4-hydroxybut-2- 4-hydroxybut-2- tesB
NP_414986 Escherichia coli adipyl-CoA 2-enoate enoyl-CoA enoyl-CoA
hydrolase acot12 NP_570103.1 Rattus norvegicus butyryl-CoA hibch
Q6NVY1.2 Homo sapiens 3- hydroxy- propanoyl- CoA 13 6.2.1.a
4-hydroxybut- 4-hydroxybut-2- 4-hydroxybut-2- sucCD NP_415256.1,
Escherichia coli succinate 2-enoate enoyl-CoA enoyl-CoA AAC73823.1
ligase (or 4-hydroxybut-2- enoyl-CoA synthetase) phl CAJ15517.1
Penicillium phenylacetate chrysogenum bioW NP_390902.2 Bacillus
subtilis 6- carboxyhexanoate 13 1.3.1.a 4-hydroxybut- 4-
4-hydroxybut-2- enr CAA71086.1 Clostridium 2-enoate hydroxybutyrate
enoate reductase tyrobutyricum enr CAA76083.1 Clostridium kluyveri
enr YP_430895.1 Moorella thermoacetica 13 2.8.3.a 4- 4-
4-hydroxybutyryl- cat1, cat2, P38946.1, Clostridium succinate, 4-
hydroxybutyrate hydroxybutyryl- CoA transferase cat3 P38942.2,
kluyveri hydroxybutyrate, coA EDK35586.1 butyrate gctA, gctB
CAA57199.1, Acidaminococcus glutarate CAA57200.1 fermentans atoA,
atoD P76459.1, Escherichia coli butanoate P76458.1 13 3.1.2.a 4- 4-
4-hydroxybutyryl- tesB NP_414986 Escherichia coli adipyl-CoA
hydroxybutyrate hydroxybutyryl- CoA hydrolase coA acot12
NP_570103.1 Rattus norvegicus butyryl-CoA hibch Q6NVY1.2 Homo
sapiens 3- hydroxy- propanoyl- CoA 13 6.2.1.a 4- 4-
4-hydroxybutyryl- sucCD NP_415256.1, Escherichia coli succinate
hydroxybutyrate hydroxybutyryl- CoA ligase (or 4- AAC73823.1 coA
hydroxybutyryl- CoA synthetase) phl CAJ15517.1 Penicillium
phenylacetate chrysogenum bioW NP_390902.2 Bacillus subtilis 6-
carboxyhexanoate 13 1.3.1.a 4-hydroxybut-2- 4- 4-hydroxybut-2- bcd,
etfA, NP_349317.1, Clostridium enoyl-CoA hydroxybutyryl- enoyl-CoA
etfB NP_349315.1, acetobutylicum CoA reductase NP_349316.1 TER
Q5EU90.1 Euglena gracilis TDE0597 NP_971211.1 Treponema denticola 8
1.1.1.c 4- 1,4-butanediol 4-hydroxybutyryl- adhE2 AAK09379.1
Clostridium butanoyl-CoA hydroxybutyryl- CoA reductase
acetobutylicum CoA (alcohol forming) mcr AAS20429.1 Chloroflexus
malonyl-CoA aurantiacus FAR AAD38039.1 Simmondsia long chain acyl-
chinensis CoA 8 1.2.1.b 4- 4- 4-hydroxybutyryl- sucD P38947.1
Clostridium Succinyl-CoA hydroxybutyryl- hydroxybutanal CoA
reductase kluyveri CoA (or 4- hydroxybutanal dehydrogenase) sucD
NP_904963.1 Porphyromonas Succinyl-CoA gingivalis Msed_0709
YP_001190808.1 Metallosphaera Malonyl-CoA sedula 8 1.1.1.a
4-hydroxybutanal 1,4-butanediol 1,4-butanediol ADH2 NP_014032.1
Saccharymyces general dehydrogenase cerevisiae yqhD NP_417484.1
Escherichia coli >C3 4hbd L21902.1 Clostridium Succinate
kluyveri semialdehyde DSM 555
Example XII
BDO Producing Strains Expressing Succinyl-CoA Synthetase
[0443] This example describes increased production of BDO in BDO
producing strains expressing succinyl-CoA synthetase.
[0444] As discussed above, succinate can be a precursor for
production of BDO by conversion to succinyl-CoA (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). Therefore, the host strain was
genetically modified to overexpress the E. coli sucCD genes, which
encode succinyl-CoA synthetase. The nucleotide sequence of the E.
coli sucCD operon is shown in FIG. 14A, and the amino acid
sequences for the encoded succinyl-CoA synthetase subunits are
shown in FIGS. 14B and 14C. Briefly, the E. coli sucCD genes were
cloned by PCR from E. coli chromosomal DNA and introduced into
multicopy plasmids pZS*13, pZA13, and pZE33 behind the PA1lacO-1
promoter (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997))
using standard molecular biology procedures.
[0445] The E. coli sucCD genes, which encode the succinyl-CoA
synthetase, were overexpressed. The results showed that introducing
into the strains sucCD to express succinyl-CoA synthetase improved
BDO production in various strains compared to either native levels
of expression or expression of cat1, which is a
succinyl-CoA/acetyl-CoA transferase. Thus, BDO production was
improved by overexpressing the native E. coli sucCD genes encoding
succinyl-CoA synthetase.
Example XIII
Expression of Heterologous Genes Encoding BDO Pathway Enzymes
[0446] This example describes the expression of various non-native
pathway enzymes to provide improved production of BDO.
[0447] Alpha-Ketoglutarate Decarboxylase.
[0448] The Mycobacterium bovis sucA gene encoding
alpha-ketoglutarate decarboxylase was expressed in host strains.
Overexpression of M. bovis sucA improved BDO production (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). The nucleotide and amino acid sequences
of M. bovis sucA and the encoded alpha-ketoglutarate decarboxylase
are shown in FIG. 15.
[0449] To construct the M. bovis sucA expressing strains, fragments
of the sucA gene encoding the alpha-ketoglutarate decarboxylase
were amplified from the genomic DNA of Mycobacterium bovis BCG
(ATCC 19015; American Type Culture Collection, Manassas Va.) using
primers shown below. The full-length gene was assembled by ligation
reaction of the four amplified DNA fragments, and cloned into
expression vectors pZS*13 and pZE23 behind the P.sub.A1lacO-1
promoter (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)).
The nucleotide sequence of the assembled gene was verified by DNA
sequencing.
TABLE-US-00074 Primers for fragment 1: (SEQ ID NO: 3)
5'-ATGTACCGCAAGTTCCGC-3' (SEQ ID NO: 4) 5'-CAATTTGCCGATGCCCAG-3'
Primers for fragment 2: (SEQ ID NO: 5) 5'-GCTGACCACTGAAGACTTTG-3'
(SEQ ID NO: 6) 5'-GATCAGGGCTTCGGTGTAG-3' Primers for fragment 3:
(SEQ ID NO: 7) 5'-TTGGTGCGGGCCAAGCAGGATCTGCTC-3' (SEQ ID NO: 8)
5'-TCAGCCGAACGCCTCGTCGAGGATCTCCTG-3' Primers for fragment 4: (SEQ
ID NO: 9) 5'-TGGCCAACATAAGTTCACCATTCGGGCAAAAC-3' (SEQ ID NO: 10)
5'-TCTCTTCAACCAGCCATTCGTTTTGCCCG-3'
[0450] Functional expression of the alpha-ketoglutarate
decarboxylase was demonstrated using both in vitro and in vivo
assays. The SucA enzyme activity was measured by following a
previously reported method (Tian et al., Proc. Natl. Acad. Sci. USA
102:10670-10675 (2005)). The reaction mixture contained 50 mM
potassium phosphate buffer, pH 7.0, 0.2 mM thiamine pyrophosphate,
1 mM MgCl.sub.2, 0.8 mM ferricyanide, 1 mM alpha-ketoglutarate and
cell crude lysate. The enzyme activity was monitored by the
reduction of ferricyanide at 430 nm. The in vivo function of the
SucA enzyme was verified using E. coli whole-cell culture. Single
colonies of E. coli MG1655 lacI.sup.q transformed with plasmids
encoding the SucA enzyme and the 4-hydroxybutyrate dehydrogenase
(4Hbd) was inoculated into 5 mL of LB medium containing appropriate
antibiotics. The cells were cultured at 37.degree. C. overnight
aerobically. A 200 uL of this overnight culture was introduced into
8 mL of M9 minimal medium (6.78 g/L Na.sub.2HPO.sub.4, 3.0 g/L
KH.sub.2PO.sub.4, 0.5 g/L NaCl, 1.0 g/L NH.sub.4Cl, 1 mM
MgSO.sub.4, 0.1 mM CaCl.sub.2) supplemented with 20 g/L glucose,
100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the
buffering capacity, 10 .mu.g/mL thiamine, and the appropriate
antibiotics. Microaerobic conditions were established by initially
flushing capped anaerobic bottles with nitrogen for 5 minutes, then
piercing the septum with a 23G needle following inoculation. The
needle was kept in the bottle during growth to allow a small amount
of air to enter the bottles. The protein expression was induced
with 0.2 mM isopropyl .beta.-D-1-thiogalactopyranoside (IPTG) when
the culture reached mid-log growth phase. As controls, E. coli
MG1655 lacI.sup.q strains transformed with only the plasmid
encoding the 4-hydroxybutyrate dehydrogenase and only the empty
vectors were cultured under the same condition (see Table 23). The
accumulation of 4-hydroxybutyrate (4HB) in the culture medium was
monitored using LCMS method. Only the E. coli strain expressing the
Mycobacterium alpha-ketoglutarate decarboxylase produced
significant amount of 4HB (see FIG. 16).
TABLE-US-00075 TABLE 24 Three strains containing various plasmid
controls and encoding sucA and 4-hydroxybutyrate dehydrogenase.
Host pZE13 pZA33 1 MG1655 lacIq vector vector 2 MG1655 lacIq vector
4hbd 3 MG1655 lacIq sucA 4hbd
[0451] A separate experiment demonstrated that the
alpha-ketoglutarate decarboxylase pathway functions independently
of the reductive TCA cycle. E. coli strain ECKh-401 (.DELTA.adhE
.DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh
.DELTA.arcA) was used as the host strain (see Table 25). All the
three constructs contained the gene encoding 4HB dehydrogenase
(4Hbd). Construct 1 also contained the gene encoding the
alpha-ketoglutarate decarboxylase (sucA). Construct 2 contained the
genes encoding the succinyl-CoA synthetase (sucCD) and the
CoA-dependent succinate semialdehyde dehydrogenase (sucD), which
are required for the synthesis of 4HB via the reductive TCA cycle.
Construct 3 contains all the genes from 1 and 2. The three E. coli
strains were cultured under the same conditions as described above
except the second culture was under the micro-aerobic condition. By
expressing the SucA enzyme, construct 3 produced more 4HB than
construct 2, which relies on the reductive TCA cycle for 4HB
synthesis (see FIG. 17).
[0452] Further support for the contribution of alpha-ketoglutarate
decarboxylase to production of 4HB and BDO was provided by flux
analysis experiments. Cultures of ECKh-432, which contains both
sucCD-sucD and sucA on the chromosome, were grown in M9 minimal
medium containing a mixture of 1-13C-glucose (60%) and
U-13C-glucose (40%). The biomass was harvested, the protein
isolated and hydrolyzed to amino acids, and the label distribution
of the amino acids analyzed by gas chromatography-mass spectrometry
(GCMS) as described previously (Fischer and Sauer, Eur. J. Biochem.
270:880-891 (2003)). In addition, the label distribution of the
secreted 4HB and BDO was analyzed by GCMS as described in
WO2008115840 A2. This data was used to calculate the intracellular
flux distribution using established methods (Suthers et al., Metab.
Eng. 9:387-405 (2007)). The results indicated that between 56% and
84% of the alpha-ketoglutarate was channeled through
alpha-ketoglutarate decarboxylase into the BDO pathway. The
remainder was oxidized by alpha-ketoglutarate dehydrogenase, which
then entered BDO via the succinyl-CoA route.
[0453] These results demonstrate 4-hydroxybutyrate producing
strains that contain the sucA gene from Mycobacterium bovis BCG
expressed on a plasmid. When the plasmid encoding this gene is not
present, 4-hydroxybutyrate production is negligible when sucD
(CoA-dependant succinate semialdehyde dehydrogenase) is not
expressed. The M. bovis gene is a close homolog of the
Mycobacterium tuberculosis gene whose enzyme product has been
previously characterized (Tian et al., supra, 2005).
[0454] Succinate Semialdehyde Dehydrogenase (CoA-Dependent),
4-Hydroxybutyrate Dehydrogenase, and
4-Hydroxybutyryl-CoA/Acetyl-CoA Transferase.
[0455] The genes from Porphyromonas gingivalis W83 can be effective
components of the pathway for 1,4-butanediol production (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). The nucleotide sequence of CoA-dependent
succinate semialdehyde dehydrogenase (sucD) from Porphyromonas
gingivalis is shown in FIG. 18A, and the encoded amino acid
sequence is shown in FIG. 18B. The nucleotide sequence of
4-hydroxybutyrate dehydrogenase (4hbd) from Porphymonas gingivalis
is shown in FIG. 19A, and the encoded amino acid sequence is shown
in FIG. 19B. The nucleotide sequence of 4-hydroxybutyrate CoA
transferase (cat2) from Porphyromonas gingivalis is shown in FIG.
20A, and the encoded amino acid sequence is shown in FIG. 20B.
[0456] Briefly, the genes from Porphyromonas gingivalis W83
encoding succinate semialdehyde dehydrogenase (CoA-dependent) and
4-hydroxybutyrate dehydrogenase, and in some cases additionally
4-hydroxybutyryl-CoA/acetyl-CoA, were cloned by PCR from P.
gingivalis chromosomal DNA and introduced into multicopy plasmids
pZS*13, pZA13, and pZE33 behind the PA1lacO-1 promoter (Lutz and
Bujard, Nucleic Acids Res. 25:1203-1210 (1997)) using standard
molecular biology procedures. These plasmids were then introduced
into host strains.
[0457] The Porphyromonas gingivalis W83 genes were introduced into
production strains as described above. Some strains included only
succinate semialdehyde dehydrogenase (CoA-dependant) and
4-hydroxybutyrate dehydrogenase without
4-hydroxybutyryl-CoA/acetyl-CoA transferase.
[0458] Butyrate Kinase and Phosphotransbutyrylase.
[0459] Butyrate kinase (BK) and phosphotransbutyrylase (PTB)
enzymes can be utilized to produce 4-hydroxybutyryl-CoA (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). In particular, the Clostridium
acetobutylicum genes, buk1 and ptb, can be utilized as part of a
functional BDO pathway.
[0460] Initial experiments involved the cloning and expression of
the native C. acetobutylicum PTB (020) and BK (021) genes in E.
coli. Where required, the start codon and stop codon for each gene
were modified to "ATG" and "TAA," respectively, for more optimal
expression in E. coli. The C. acetobutylicum gene sequences (020N
and 021N) and their corresponding translated peptide sequences are
shown in FIGS. 21 and 22.
[0461] The PTB and BK genes exist in C. acetobutylicum as an
operon, with the PTB (020) gene expressed first. The two genes are
connected by the sequence "atta aagttaagtg gaggaatgtt aac" (SEQ ID
NO:11) that includes a re-initiation ribosomal binding site for the
downstream BK (021) gene. The two genes in this context were fused
to lac-controlled promoters in expression vectors for expression in
E. coli (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210
(1997)).
[0462] Expression of the two proteins from these vector constructs
was found to be low in comparison with other exogenously expressed
genes due to the high incidence of codons in the C. acetobutylicum
genes that occur only rarely in E. coli. Therefore new 020 and 021
genes were predicted that changed rare codons for alternates that
are more highly represented in E. coli gene sequences. This method
of codon optimization followed algorithms described previously
(Sivaraman et al., Nucleic Acids Res. 36:e16(2008)). This method
predicts codon replacements in context with their frequency of
occurrence when flanked by certain codons on either side.
Alternative gene sequences for 020 (FIG. 23) and 021 (FIG. 24) were
determined in which increasing numbers of rare codons were replaced
by more prevalent codons (A<B<C<D) based on their
incidence in the neighboring codon context. No changes in actual
peptide sequence compared to the native 020 and 021 peptide
sequences were introduced in these predicted sequences.
[0463] The improvement in expression of the BK and PTB proteins
resulting from codon optimization is shown in FIG. 25A. Expression
of the native gene sequences is shown in lane 2, while expression
of the 020B-021B and 020C-021C is shown in lanes 3 and 4,
respectively. Higher levels of protein expression in the
codon-optimized operons 020B-021B (2021B) and 020C-021C (2021C)
also resulted in increased activity compared to the native operon
(2021n) in equivalently-expressed E. coli crude extracts (FIG.
25B).
[0464] The codon optimized operons were expressed on a plasmid in
strain ECKh-432 (.DELTA.adhE .DELTA.ldhA .DELTA.pflB
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA gltAR163L fimD:: E.
coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis
sucA, C. kluyveri 4hbd) along with the C. acetobutylicum aldehyde
dehydrogenase to provide a complete BDO pathway. Cells were
cultured in M9 minimal medium containing 20 g/L glucose, using a
23G needle to maintain microaerobic conditions as described above.
The resulting conversion of glucose to the final product BDO was
measured. Also measured was the accumulation of gamma-butyrylactone
(GBL), which is a spontaneously rearranged molecule derived from
4Hb-CoA, the immediate product of the PTB-BK enzyme pair. FIG. 26
shows that expression of the native 2021n operon resulted in
comparable BDO levels to an alternative enzyme function, Cat2
(034), that is capable of converting 4HB and free CoA to 4HB-CoA.
GBL levels of 034 were significantly higher than 2021n, suggesting
that the former enzyme has more activity than PTB-BK expressed from
the native genes. However levels of both BDO and GBL were higher
than either 034 or 2021n when the codon-optimized variants 2021B
and 2021C were expressed, indicating that codon optimization of the
genes for PTB and BK significantly increases their contributions to
BDO synthesis in E. coli.
[0465] These results demonstrate that butyrate kinase (BK) and
phosphotransbutyrylase (PTB) enzymes can be employed to convert
4-hydroxybutyrate to 4-hydroxybutyryl-CoA. This eliminates the need
for a transferase enzyme such as 4-hydroxybutyryl-CoA/Acetyl-CoA
transferase, which would generate one mole of acetate per mol of
4-hydroxybutyryl-CoA produced. The enzymes from Clostridium
acetobutylicum are present in a number of engineered strains for
BDO production.
[0466] 4-Hydroxybutyryl-CoA Reductase.
[0467] The Clostridium beijerinckii ald gene can be utilized as
part of a functional BDO pathway (see also WO2008/115840, WO
2009/023493, U.S. publication 2009/0047719, U.S. publication
2009/0075351). The Clostridium beijerinckii ald can also be
utilized to lower ethanol production in BDO producing strains.
Additionally, a specific codon-optimized ald variant (GNM0025B) was
found to improve BDO production.
[0468] The native C. beijerinckii ald gene (025n) and the predicted
protein sequence of the enzyme are shown in FIG. 27. As was seen
for the Clostridium acetobutylicum PTB and BK genes, expression of
the native C. beijerinckii ald gene was very low in E. coli.
Therefore, four codon-optimized variants for this gene were
predicted. FIGS. 28A-28D show alternative gene sequences for 025,
in which increasing numbers of rare codons are replaced by more
prevalent codons (A<B<C<D) based on their incidence in the
neighboring codon context (25A, P=0.05; 25B, P=0.1; 25C, P=0.15;
25D, P=1). No changes in actual peptide sequence compared to the
native 025 peptide sequence were introduced in these predictions.
Codon optimization significantly increased expression of the C.
beijerinckii ald (see FIG. 29), which resulted in significantly
higher conversion of glucose to BDO in cells expressing the entire
BDO pathway (FIG. 30A).
[0469] The native and codon-optimized genes were expressed on a
plasmid along with P. gingivalis Cat2, in the host strain ECKh-432
(.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA gltAR163L .DELTA.ackA fimD:: E. coli sucCD,
P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C.
kluyveri 4hbd), thus containing a complete BDO pathway. Cells were
cultured microaerobically in M9 minimal medium containing 20 g/L
glucose as described above. The relative production of BDO and
ethanol by the C. beijerinckii Ald enzyme (expressed from
codon-optimized variant gene 025B) was compared with the C.
acetobutylicum AdhE2 enzyme (see FIG. 30B). The C. acetobutylicum
AdhE2 enzyme (002C) produced nearly 4 times more ethanol than BDO.
In comparison, the C. beijerinckii Ald (025B) (in conjunction with
an endogenous ADH activity) produced equivalent amounts of BDO, yet
the ratio of BDO to ethanol production was reversed for this enzyme
compared to 002C. This suggests that the C. beijerinckii Ald is
more specific for 4HB-CoA over acetyl-coA than the C.
acetobutylicum AdhE2, and therefore the former is the preferred
enzyme for inclusion in the BDO pathway.
[0470] The Clostridium beijerinckii ald gene (Toth et al., Appl.
Environ. Microbiol. 65:4973-4980 (1999)) was tested as a candidate
for catalyzing the conversion of 4-hydroxybutyryl-CoA to
4-hydroxybutanal. Over fifty aldehyde dehydrogenases were screened
for their ability to catalyze the conversion of
4-hydroxybutyryl-CoA to 4-hydroxybutyraldehyde. The C. beijerinckii
ald gene was chosen for implementation into BDO-producing strains
due to the preference of this enzyme for 4-hydroxybutyryl-CoA as a
substrate as opposed to acetyl-CoA. This is important because most
other enzymes with aldehyde dehydrogenase functionality (for
example, adhE2 from C. acetobutylicum (Fontaine et al., J
Bacteriol. 184:821-830 (2002)) preferentially convert acetyl-CoA to
acetaldehyde, which in turn is converted to ethanol. Utilization of
the C. beijerinckii gene lowers the amount of ethanol produced as a
byproduct in BDO-producing organisms. Also, a codon-optimized
version of this gene expresses very well in E. coli (Sivaraman et
al., Nucleic Acids Res. 36:e16 (2008)).
[0471] 4-Hydroxybutanal Reductase.
[0472] 4-hydroxybutanal reductase activity of adh1 from Geobacillus
thermoglucosidasius (M10EXG) was utilized. This led to improved BDO
production by increasing 4-hydroxybutanal reductase activity over
endogenous levels.
[0473] Multiple alcohol dehydrogenases were screened for their
ability to catalyze the reduction of 4-hydroxybutanal to BDO. Most
alcohol dehydrogenases with high activity on butyraldehyde
exhibited far lower activity on 4-hydroxybutyraldehyde. One notable
exception is the adh1 gene from Geobacillus thermoglucosidasius
M10EXG (Jeon et al., J Biotechnol. 135:127-133 (2008)) (GNM0084),
which exhibits high activity on both 4-hydroxybutanal and
butanal.
[0474] The native gene sequence and encoded protein sequence if the
adh1 gene from Geobacillus thermoglucosidasius are shown in FIG.
31. The G. thermoglucosidasius ald1 gene was expressed in E.
coli.
[0475] The Adh1 enzyme (084) expressed very well from its native
gene in E. coli (see FIG. 32A). In ADH enzyme assays, the E. coli
expressed enzyme showed very high reductive activity when
butyraldehyde or 4HB-aldehyde were used as the substrates (see FIG.
32B). The Km values determined for these substrates were 1.2 mM and
4.0 mM, respectively. These activity values showed that the Adh1
enzyme was the most active on reduction of 4HB-aldehyde of all the
candidates tested.
[0476] The 084 enzyme was tested for its ability to boost BDO
production when coupled with the C. beijerinckii ald. The 084 gene
was inserted behind the C. beijerinckii ald variant 025B gene to
create a synthetic operon that results in coupled expression of
both genes. Similar constructs linked 025B with other ADH candidate
genes, and the effect of including each ADH with 025B on BDO
production was tested. The host strain used was ECKh-459
(.DELTA.adhE ldhA .DELTA.pflB .DELTA.lpdA::fnr-pflB6-K.p.lpdA322
.DELTA.mdh .DELTA.arcA gltAR163L fimD:: E. coli sucCD, P.
gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C.
kluyveri 4hbd fimD:: C. acetobutylicum buk1, C. acetobutylicum
ptb), which contains the remainder of the BDO pathway on the
chromosome. The 084 ADH expressed in conjunction with 025B showed
the highest amount of BDO (right arrow in FIG. 33) when compared
with 025B only (left arrow in FIG. 33) and in conjunction with
endogenous ADH functions. It also produced more BDO than did other
ADH enzymes when paired with 025B, indicated as follows: 026A-C,
codon-optimized variants of Clostridium acetobutylicum butanol
dehydrogenase; 050, Zymomonas mobilis alcohol dehydrogenase I; 052,
Citrobacter freundii 1,3-propanediol dehydrogenase; 053,
Lactobacillus brevis 1,3-propanediol dehydrogenase; 057,
Bacteroides fragilis lactaldehyde reductase; 058, E. coli
1,3-propanediol dehydrogenase; 071, Bacillus subtilis 168
alpha-ketoglutarate semialdehyde dehydrogenase. The constructs
labeled "PT5lacO" are those in which the genes are driven by the
PT5lacO promoter. In all other cases, the PA1lacO-1 promoter was
used. This shows that inclusion of the 084 ADH in the BDO pathway
increased BDO production.
Example XIV
BDO Producing Strains Expressing Pyruvate Dehydrogenase
[0477] This example describes the utilization of pyruvate
dehydrogenase (PDH) to enhance BDO production. Heterologous
expression of the Klebsiella pneumonia lpdA gene was used to
enhance BDO production.
[0478] Computationally, the NADH-generating conversion of pyruvate
to acetyl-CoA is required to reach the maximum theoretical yield of
1,4-butanediol (see also WO2008/115840, WO 2009/023493, U.S.
publication 2009/0047719, U.S. publication 2009/0075351; WO
2008/018930; Kim et al., Appl. Environ. Microbiol. 73:1766-1771
(2007); Kim et al., J. Bacteriol. 190:3851-3858 (2008); Menzel et
al., J. Biotechnol. 56:135-142 (1997)). Lack of PDH activity was
shown to reduce the maximum anaerobic theoretical yield of BDO by
11% if phosphoenolpyruvate carboxykinase (PEPCK) activity cannot be
attained and by 3% if PEPCK activity can be attained. More
importantly, however, absence of PDH activity in the OptKnock
strain #439, described in WO 2009/023493 and U.S. publication
2009/0047719, which has the knockout of ADHEr, ASPT, LDH_D, MDH and
PFLi, would reduce the maximum anaerobic yield of BDO by 54% or by
43% if PEPCK activity is absent or present, respectively. In the
presence of an external electron acceptor, lack of PDH activity
would reduce the maximum yield of the knockout strain by 10% or by
3% assuming that PEPCK activity is absent or present,
respectively.
[0479] PDH is one of the most complicated enzymes of central
metabolism and is comprised of 24 copies of pyruvate decarboxylase
(E1) and 12 molecules of dihydrolipoyl dehydrogenase (E3), which
bind to the outside of the dihydrolipoyl transacetylase (E2) core.
PDH is inhibited by high NADH/NAD, ATP/ADP, and Acetyl-CoA/CoA
ratios. The enzyme naturally exhibits very low activity under
oxygen-limited or anaerobic conditions in organisms such as E. coli
due in large part to the NADH sensitivity of E3, encoded by lpdA.
To this end, an NADH-insensitive version of the lpdA gene from
Klebsiella pneumonia was cloned and expressed to increase the
activity of PDH under conditions where the NADH/NAD ratio is
expected to be high.
[0480] Replacement of the Native lpdA.
[0481] The pyruvate dehydrogenase operon of Klebsiella pneumoniae
is between 78 and 95% identical at the nucleotide level to the
equivalent operon of E. coli. It was shown previously that K.
pneumoniae has the ability to grow anaerobically in presence of
glycerol (Menzel et al., J. Biotechnol. 56:135-142 (1997); Menzel
et al., Biotechnol. Bioeng. 60:617-626 (1998)). It has also been
shown that two mutations in the lpdA gene of the operon of E. coli
would increase its ability to grow anaerobically (Kim et al. Appl.
Environ. Microbiol. 73:1766-1771 (2007); Kim et al., J. Bacteriol.
190:3851-3858 (2008)). The lpdA gene of K. pneumonia was amplified
by PCR using genomic DNA (ATCC700721D) as template and the primers
KP-lpdA-Bam (5'-acacgcggatccaacgtcccgg-3')(SEQ ID NO:12) and
KP-lpdA-Nhe (5'-agcggctccgctagccgcttatg-3')(SEQ ID NO:13). The
resulting fragment was cloned into the vector pCR-BluntII-TOPO
(Invitrogen; Carlsbad Calif.), leading to plasmid pCR-KP-lpdA.
[0482] The chromosomal gene replacement was performed using a
non-replicative plasmid and the sacB gene from Bacillus subtilis as
a means of counterselection (Gay et al., J. Bacteriol.
153:1424-1431 (1983)). The vector used is pRE118 (ATCC87693)
deleted of the oriT and IS sequences, which is 3.6 kb in size and
carrying the kanamycin resistance gene. The sequence was confirmed,
and the vector was called pRE118-V2 (see FIG. 34).
[0483] The E. coli fragments flanking the lpdA gene were amplified
by PCR using the combination of primers: EC-aceF-Pst
(5'-aagccgttgctgcagctcttgagc-3')(SEQ ID NO:14)+EC-aceF-Bam2
(5'-atctccggcggtcggatccgtcg-3')(SEQ ID NO:15) and EC-yacH-Nhe
(5'-aaagcggctagccacgccgc-3')(SEQ ID NO:16)+EC-yacH-Kpn
(5'-attacacgaggtacccaacg-3')(SEQ ID NO:17). A BamHI-XbaI fragment
containing the lpdA gene of K. pneumonia was isolated from plasmid
pCR-KP-lpdA and was then ligated to the above E. coli fragments
digested with PstI+BamHI and NheI-KpnI respectively, and the
pRE118-V2 plasmid digested with KpnI and PstI. The resulting
plasmid (called pRE118-M2.1 lpdA yac) was subjected to Site
Directed Mutagenesis (SDM) using the combination of primers
KP-lpdA-HisTyr-F (5'-atgctggcgtacaaaggtgtcc-3')(SEQ ID NO:18) and
(5'-ggacacctttgtacgccagcat-3')(SEQ ID NO:19) for the mutation of
the His 322 residue to a Tyr residue or primers KP-lpdA-GluLys-F
(5'-atcgcctacactaaaccagaagtgg-3')(SEQ ID NO:20) and
KP-lpdA-GluLys-R (5'-ccacttctggtttagtgtaggcgat-3')(SEQ ID NO:21)
for the mutation of the residue Glu 354 to Lys residue. PCR was
performed with the Polymerase Pfu Turbo (Stratagene; San Diego
Calif.). The sequence of the entire fragment as well as the
presence of only the desired mutations was verified. The resulting
plasmid was introduced into electro competent cells of E. coli
.DELTA.adhE::Frt-.DELTA.ldhA::Frt by transformation. The first
integration event in the chromosome was selected on LB agar plates
containing Kanamycin (25 or 50 mg/L). Correct insertions were
verified by PCR using 2 primers, one located outside the region of
insertion and one in the kanamycin gene
(5'-aggcagttccataggatggc-3')(SEQ ID NO:22). Clones with the correct
insertion were selected for resolution. They were sub-cultured
twice in plain liquid LB at the desired temperature and serial
dilutions were plated on LB-no salt-sucrose 10% plates. Clones that
grew on sucrose containing plates were screened for the loss of the
kanamycin resistance gene on LB-low salt agar medium and the lpdA
gene replacement was verified by PCR and sequencing of the
encompassing region. Sequence of the insertion region was verified,
and is as described below. One clone (named 4-4-P1) with mutation
Glu354Lys was selected. This clone was then transduced with P1
lysate of E. coli .DELTA.PflB::Frt leading to strain ECKh-138
(.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322).
[0484] The sequence of the ECKh-138 region encompassing the aceF
and lpdA genes is shown in FIG. 35. The K. pneumonia lpdA gene is
underlined, and the codon changed in the Glu354Lys mutant shaded.
The protein sequence comparison of the native E. coli lpdA and the
mutant K. pneumonia lpdA is shown in FIG. 36.
[0485] To evaluate the benefit of using K. pneumoniae lpdA in a BDO
production strain, the host strains AB3 and ECKh-138 were
transformed with plasmids expressing the entire BDO pathway from
strong, inducible promoters. Specifically, E. coli sucCD, P.
gingivalis sucD, P. gingivalis 4hbd were expressed on the medium
copy plasmid pZA33, and P. gingivalis Cat2 and C. acetobutylicum
AdhE2 were expressed on the high copy plasmid pZE13. These plasmids
have been described in the literature (Lutz and H. Bujard, Nucleic
Acids Res 25:1203-1210 (1997)), and their use for BDO pathway
expression is described in Example XIII and WO2008/115840.
[0486] Cells were grown anaerobically at 37.degree. C. in M9
minimal medium (6.78 g/L Na.sub.2HPO.sub.4, 3.0 g/L
KH.sub.2PO.sub.4, 0.5 g/L NaCl, 1.0 g/L NH.sub.4Cl, 1 mM
MgSO.sub.4, 0.1 mM CaCl.sub.2) supplemented with 20 g/L glucose,
100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the
buffering capacity, 10 .mu.g/mL thiamine, and the appropriate
antibiotics. Microaerobic conditions were established by initially
flushing capped anaerobic bottles with nitrogen for 5 minutes, then
piercing the septum with a 23G needle following inoculation. The
needle was kept in the bottle during growth to allow a small amount
of air to enter the bottles. 0.25 mM IPTG was added when OD600
reached approximately 0.2 to induce the pathway genes, and samples
taken for analysis every 24 hours following induction. The culture
supernatants were analyzed for BDO, 4HB, and other by-products as
described in Example II and in WO2008/115840. BDO and 4HB
production in ECKh-138 was significantly higher after 48 hours than
in AB3 or the host used in previous work, MG1655 .DELTA.ldhA (FIG.
37).
[0487] PDH Promoter Replacement.
[0488] It was previously shown that the replacement of the pdhR
repressor by a transcriptional fusion containing the Fnr binding
site, one of the pflB promoters, and its ribosome binding site
(RBS), thus leading to expression of the aceEF-lpd operon by an
anaerobic promoter, should increase pdh activity anaerobically
(Zhou et al., Biotechnol. Lett. 30:335-342 (2008)). A fusion
containing the Fnr binding site, the pflB-p6 promoter and an RBS
binding site were constructed by overlapping PCR. Two fragments
were amplified, one using the primers aceE-upstream-RC
(5'-tgacatgtaacacctaccttctgtgcctgtgccagtggttgctgtgatatagaag-3')(SEQ
ID NO:23) and pflBp6-Up-Nde
(5'-ataataatacatatgaaccatgcgagttacgggcctataagccaggcg-3')(SEQ ID
NO:24) and the other using primers aceE-EcoRV-EC
(5'-agtttttcgatatctgcatcagacaccggcacattgaaacgg-3')(SEQ ID NO:25)
and aceE-upstream
(5'-ctggcacaggcacagaaggtaggtgttacatgtcagaacgtttacacaatgacgtggatc-3')(SEQ
ID NO:26). The tw fragments were assembled by overlapping PCR, and
the final DNA fragment was digested with the restriction enzymes
NdeI and BamHI. This fragment was subsequently introduced upstream
of the aceE gene of the E. coli operon using pRE118-V2 as described
above. The replacement was done in strains ECKh-138 and ECKh-422.
The nucleotide sequence encompassing the 5' region of the aceE gene
was verified and is shown in FIG. 37. FIG. 37 shows the nucleotide
sequence of 5' end of the aceE gene fused to the pflB-p6 promoter
and ribosome binding site (RBS). The 5' italicized sequence shows
the start of the aroP gene, which is transcribed in the opposite
direction from the pdh operon. The 3' italicized sequence shows the
start of the aceE gene. In upper case: pflB RBS. Underlined: FNR
binding site. In bold: pflB-p6 promoter sequence.
[0489] lpdA Promoter Replacement.
[0490] The promoter region containing the fnr binding site, the
pflB-p6 promoter and the RBS of the pflB gene was amplified by PCR
using chromosomal DNA template and primers aceF-pflBp6-fwd
(5'-agacaaatcggttgccgtttgttaagccaggcgagatatgatctatatc-3')(SEQ ID
NO:27) and lpdA-RB S-B-rev
(5'-gagttttgatttcagtactcatcatgtaacacctaccttcttgctgtgatatag-3')(SEQ
ID NO:28). Plasmid 2-4a was amplified by PCR using primers
B-RBS-lpdA fwd
(5'-ctatatcacagcaagaaggtaggtgttacatgatgagtactgaaatcaaaactc-3')(SEQ
ID NO:29) and pflBp6-aceF-rev
(5'-gatatagatcatatctcgcctggcttaacaaacggcaaccgatttgtct-3')(SEQ ID
NO:30). The two resulting fragments were assembled using the BPS
cloning kit (BPS Bioscience; San Diego Calif.). The resulting
construct was sequenced verified and introduced into strain
ECKh-439 using the pRE118-V2 method described above. The nucleotide
sequence encompassing the aceF-lpdA region in the resulting strain
ECKh-456 is shown in FIG. 39.
[0491] The host strain ECKh-439 (.DELTA.adhE .DELTA.ldhA
.DELTA.pflB .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA
gltAR163L ackA fimD:: E. coli sucCD, P. gingivalis sucD, P.
gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd), the
construction of which is described below, and the pdhR and lpdA
promoter replacement derivatives ECKh-455 and ECKh-456, were tested
for BDO production. The strains were transformed with pZS*13
containing P. gingivalis Cat2 and C. beijerinckii Ald to provide a
complete BDO pathway. Cells were cultured in M9 minimal medium
supplemented with 20 g/L glucose as described above. 48 hours after
induction with 0.2 mM IPTG, the concentrations of BDO, 4HB, and
pyruvate were as shown in FIG. 40. The promoter replacement strains
produce slightly more BDO than the isogenic parent.
[0492] These results demonstrated that expression of pyruvate
dehydrogenase increased production of BDO in BDO producing
strains.
Example XV
BDO Producing Strains Expressing Citrate Synthase and Aconitase
[0493] This example describes increasing activity of citrate
synthase and aconitase to increase production of BDO. An R163L
mutation into gltA was found to improve BDO production.
Additionally, an arcA knockout was used to improve BDO
production.
[0494] Computationally, it was determined that flux through citrate
synthase (CS) and aconitase (ACONT) is required to reach the
maximum theoretical yield of 1,4-butanediol (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). Lack of CS or ACONT activity would
reduce the maximum theoretical yield by 14% under anaerobic
conditions. In the presence of an external electron acceptor, the
maximum yield is reduced by 9% or by 6% without flux through CS or
ACONT assuming the absence or presence of PEPCK activity,
respectively. As with pyruvate dehydrogenase (PDH), the importance
of CS and ACONT is greatly amplified in the knockout strain
background in which ADHEr, ASPT, LDH_D, MDH and PFLi are knocked
out (design #439)(see WO 2009/023493 and U.S. publication
2009/0047719, which is incorporated herein by reference).
[0495] The minimal OptKnock strain design described in WO
2009/023493 and U.S. publication 2009/0047719 had one additional
deletion beyond ECKh-138, the mdh gene, encoding malate
dehydrogenase. Deletion of this gene is intended to prevent flux to
succinate via the reductive TCA cycle. The mdh deletion was
performed using the .lamda. red homologeous recombination method
(Datsenko and Wanner, Proc. Natl. Acad. Sci. USA 97:6640-6645
(2000)). The following oligonucleotides were used to PCR amplify
the chloramphenicol resistance gene (CAT) flanked by FRT sites from
pKD3:
TABLE-US-00076 S-mdh-Kan (SEQ ID NO: 31) 5'-TAT TGT GCA TAC AGA TGA
ATT TTT ATG CAA ACA GTC AGC CCT GAA GAA GGG TGT AGG CTG GAG CTG CTT
C-3' AS-mdh-Kan (SEQ ID NO: 32) 5'-CAA AAA ACC GGA GTC TGT GCT CCG
GTT TTT TAT TAT CCG CTA ATC AAT TAC ATA TGA ATA TCC TCC TTA
G-3'.
Underlined regions indicate homology to pKD3 plasmid and bold
sequence refers to sequence homology upstream and downstream of the
mdh ORF. After purification, the PCR product was electroporated
into ECKh-138 electrocompetent cells that had been transformed with
pRedET (tet) and prepared according to the manufacturer's
instructions
(genebridges.com/gb/pdf/K001%20Q%20E%20BAC%20Modification%20Kit-version2.-
6-2007-screen.pdf). The PCR product was designed so that it
integrated into the ECKh-138 genome at a region upstream of the mdh
gene, as shown in FIG. 41.
[0496] Recombinants were selected for chloramphenicol resistance
and streak purified. Loss of the mdh gene and insertion of CAT was
verified by diagnostic PCR. To remove the CAT gene, a temperature
sensitive plasmid pCP20 containing a FLP recombinase (Datsenko and
Wanner, Proc. Natl. Acad. Sci. USA 97:6640-6645 (2000)) was
transformed into the cell at 30.degree. C. and selected for
ampicillin resistance (AMP). Transformants were grown
nonselectively at 42.degree. C. overnight to thermally induce FLP
synthesis and to cause lose of the plasmid. The culture was then
streak purified, and individual colonies were tested for loss of
all antibiotic resistances. The majority lost the FRT-flanked
resistance gene and the FLP helper plasmid simultaneously. There
was also a "FRT" scar leftover. The resulting strain was named
ECKh-172.
[0497] CS and ACONT are not highly active or highly expressed under
anaerobic conditions. To this end, the arcA gene, which encodes for
a global regulator of the TCA cycle, was deleted. ArcA works during
microaerobic conditions to induce the expression of gene products
that allow the activity of central metabolism enzymes that are
sensitive to low oxygen levels, aceE, pflB and adhE. It was shown
that microaerobically, a deletion in arcA/arcB increases the
specific activities of ldh, icd, gltA, mdh, and gdh genes (Salmon
et al., J. Biol. Chem. 280:15084-15096 (2005); Shalel-Levanon et
al., Biotechnol. Bioeng. 92(2):147-159 (2005). The upstream and
downstream regions of the arcA gene of E. coli MG1655 were
amplified by PCR using primers ArcA-up-EcoRI
(5'-ataataatagaattcgtttgctacctaaattgccaactaaatcgaaacagg-3')(SEQ ID
NO:33) with ArcA-up-KpnI
(5'-tattattatggtaccaatatcatgcagcaaacggtgcaacattgccg-3')(SEQ ID
NO:34) and ArcA-down-EcoRI
(5'-tgatctggaagaattcatcggattaccaccgtcaaaaaaaacggcg-3')(SEQ ID
NO:35) with ArcA-down-PstI
(5'-ataaaaccctgcagcggaaacgaagttttatccatttttggttacctg-3')(SEQ ID
NO:36), respectively. These fragments were subsequently digested
with the restriction enzymes EcoRI and KpnI (upstream fragment) and
EcoRI and PstI (downstream). They were then ligated into the
pRE118-V2 plasmid digested with PstI and KpnI, leading to plasmid
pRE118-.DELTA.arcA. The sequence of plasmid pRE118-.DELTA.arcA was
verified. pRE118-.DELTA.arcA was introduced into electro-competent
cells of E. coli strain ECKh-172 (.DELTA.adhE .DELTA.ldhA
.DELTA.pflB .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh). After integration
and resolution on LB-no salt-sucrose plates as described above, the
deletion of the arcA gene in the chromosome of the resulting strain
ECKh-401 was verified by sequencing and is shown in FIG. 42.
[0498] The gltA gene of E. coli encodes for a citrate synthase. It
was previously shown that this gene is inhibited allosterically by
NADH, and the amino acids involved in this inhibition have been
identified (Pereira et al., J. Biol. Chem. 269(1):412-417 (1994);
Stokell et al., J. Biol. Chem. 278(37):35435-35443 (2003)). The
gltA gene of E. coli MG1655 was amplified by PCR using primers
gltA-up (5'-ggaagagaggctggtacccagaagccacagcagga-3')(SEQ ID NO:37)
and gltA-PstI (5'-gtaatcactgcgtaagcgccatgccccggcgttaattc-3')(SEQ ID
NO:38). The amplified fragment was cloned into pRE118-V2 after
digestion with KpnI and PstI. The resulting plasmid was called
pRE118-gltA. This plasmid was then subjected to site directed
mutagensis (SDM) using primers R163L-f
(5'-attgccgcgttcctcctgctgtcga-3')(SEQ ID NO:39) and R163L-r
(5'-cgacagcaggaggaacgcggcaat-3')(SEQ ID NO:40) to change the
residue Arg 163 to a Lys residue. The sequence of the entire
fragment was verified by sequencing. A variation of the .lamda. red
homologeous recombination method (Datsenko and Wanner, Proc. Natl.
Acad. Sci. USA 97:6640-6645 (2000)) was used to replace the native
gltA gene with the R163L mutant allele without leaving a Frt scar.
The general recombination procedure is the same as used to make the
mdh deletion described above. First, the strain ECKh-172 was made
streptomycin resistant by introducing an rpsL null mutation using
the X red homologeous recombination method. Next, a recombination
was done to replace the entire wild-type gltA coding region in this
strain with a cassette comprised of a kanamycin resistance gene
(kanR) and a wild-type copy of the E. coli rpsL gene. When
introduced into an E. coli strain harboring an rpsL null mutation,
the cassette causes the cells to change from resistance to the drug
streptomycin to streptomycin sensitivity. DNA fragments were then
introduced that included each of the mutant versions of the gltA
gene along with appropriate homologous ends, and resulting colony
growth was tested in the presence of streptomycin. This selected
for strains in which the kanR/rpsL cassette had been replaced by
the mutant gltA gene. Insertion of the mutant gene in the correct
locus was confirmed by PCR and DNA sequencing analyses. The
resulting strain was called ECKh-422, and has the genotype
.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA gltAR163L. The region encompassing the
mutated gltA gene of strain ECKh-422 was verified by sequencing, as
shown in FIG. 43.
[0499] Crude extracts of the strains ECKh-401 and the gltAR163L
mutant ECKh-422 were then evaluated for citrate synthase activity.
Cells were harvested by centrifugation at 4,500 rpm
(Beckman-Coulter, Allegera X-15R; Fullerton Calif.) for 10 min. The
pellets were resuspended in 0.3 mL BugBuster (Novagen/EMD; San
Diego Calif.) reagent with benzonase and lysozyme, and lysis
proceeded for 15 minutes at room temperature with gentle shaking.
Cell-free lysate was obtained by centrifugation at 14,000 rpm
(Eppendorf centrifuge 5402; Hamburg Germany) for 30 min at
4.degree. C. Cell protein in the sample was determined using the
method of Bradford (Bradford, Anal. Biochem. 72:248-254
(1976)).
[0500] Citrate synthase activity was determined by following the
formation of free coenzyme A (HS-CoA), which is released from the
reaction of acetyl-CoA with oxaloacetate. The free thiol group of
HS-CoA reacts with 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) to
form 5-thio-2-nitrobenzoic acid (TNB). The concentration of TNB is
then monitored spectrophotometrically by measuring the absorbance
at 410 nm (maximum at 412 nm). The assay mixture contained 100 mM
Tris/HCl buffer (pH 7.5), 20 mM acetyl-CoA, 10 mM DTNB, and 20 mM
oxaloacetate. For the evaluation of NADH inhibition, 0.4 mM NADH
was also added to the reaction. The assay was started by adding 5
microliters of the cell extract, and the rate of reaction was
measured by following the absorbance change over time. A unit of
specific activity is defined as the .mu.mol of product converted
per minute per mg protein.
[0501] FIG. 44 shows the citrate synthase activity of wild type
gltA gene product and the R163L mutant. The assay was performed in
the absence or presence of 0.4 mM NADH.
[0502] Strains ECKh-401 and ECKh-422 were transformed with plasmids
expressing the entire BDO pathway. E. coli sucCD, P. gingivalis
sucD, P. gingivalis 4hbd, and M. bovis sucA were expressed on the
low copy plasmid pZS*13, and P. gingivalis Cat2 and C.
acetobutylicum AdhE2 were expressed on the medium copy plasmid
pZE23. Cultures of these strains were grown microaerobically in M9
minimal medium supplemented with 20 g/L glucose and the appropriate
antibiotics as described above. The 4HB and BDO concentrations at
48 hours post-induction averaged from duplicate cultures are shown
in FIG. 45. Both are higher in ECKh-422 than in ECKh-401,
demonstrating that the enhanced citrate synthase activity due to
the gltA mutation results in increased flux to the BDO pathway.
[0503] The host strain modifications described in this section were
intended to redirect carbon flux through the oxidative TCA cycle,
which is consistent with the OptKnock strain design described in WO
2009/023493 and U.S. publication 2009/0047719. To demonstrate that
flux was indeed routed through this pathway, .sup.13C flux analysis
was performed using the strain ECKh-432, which is a version of
ECKh-422 in which the upstream pathway is integrated into the
chromosome (as described in Example XVII). To complete the BDO
pathway, P. gingivalis Cat2 and C. beijerinckii Ald were expressed
from pZS*13. Four parallel cultures were grown in M9 minimal medium
(6.78 g/L Na.sub.2HPO.sub.4, 3.0 g/L KH.sub.2PO.sub.4, 0.5 g/L
NaCl, 1.0 g/L NH.sub.4Cl, 1 mM MgSO.sub.4, 0.1 mM CaCl.sub.2)
containing 4 g/L total glucose of four different labeling ratios
(.sup.1-13C, only the first carbon atom in the glucose molecule is
labeled with .sup.13C; uniform-.sup.13C, all carbon atoms are
.sup.13C): [0504] 1. 80 mol % unlabeled, 20 mol % uniform-.sup.13C
[0505] 2. 10 mol % unlabeled, 90 mol % uniform-.sup.13C [0506] 3.
90 mol % .sup.1-13C, 10 mol % uniform-.sup.13C [0507] 4. 40 mol %
.sup.1-13C, 60 mol % uniform-.sup.13C
[0508] Parallel unlabeled cultures were grown in duplicate, from
which frequent samples were taken to evaluate growth rate, glucose
uptake rate, and product formation rates. In late exponential
phase, the labeled cultures were harvested, the protein isolated
and hydrolyzed to amino acids, and the label distribution of the
amino acids analyzed by gas chromatography-mass spectrometry (GCMS)
as described previously (Fischer and Sauer, Eur. J. Biochem.
270:880-891 (2003)). In addition, the label distribution of the
secreted 4HB and BDO in the broth from the labeled cultures was
analyzed by GCMS as described in WO2008115840. This data was
collectively used to calculate the intracellular flux distribution
using established methods (Suthers et al., Metab. Eng. 9:387-405
(2007)). The resulting central metabolic fluxes and associated 95%
confidence intervals are shown in FIG. 46. Values are molar fluxes
normalized to a glucose uptake rate of 1 mmol/hr. The result
indicates that carbon flux is routed through citrate synthase in
the oxidative direction, and that most of the carbon enters the BDO
pathway rather than completing the TCA cycle. Furthermore, it
confirms there is essentially no flux between malate and
oxaloacetate due to the mdh deletion in this strain.
[0509] The advantage of using a knockout strain such as strains
designed using OptKnock for BDO production (see WO 2009/023493 and
U.S. publication 2009/0047719) can be observed by comparing typical
fermentation profiles of ECKh-422 with that of the original strain
ECKh-138, in which BDO is produced from succinate via the reductive
TCA cycle (see FIG. 47). Fermentations were performed with 1 L
initial culture volume in 2 L Biostat B+ bioreactors (Sartorius;
Cedex France) using M9 minimal medium supplemented with 20 g/L
glucose. The temperature was controlled at 37.degree. C., and the
pH was controlled at 7.0 using 2 M NH.sub.4OH or Na.sub.2CO.sub.3.
Cells were grown aerobically to an OD600 of approximately 10, at
which time the cultures were induced with 0.2 mM IPTG. One hour
following induction, the air flow rate was reduced to 0.02 standard
liters per minute for microaerobic conditions. The agitation rate
was set at 700 rpm. Concentrated glucose was fed to maintain
glucose concentration in the vessel between 0.5 and 10 g/L. Both
strains were transformed with plasmids bearing the entire BDO
pathway, as in the examples above. In ECKh-138, acetate, pyruvate,
and 4HB dominate the fermentation, while with ECKh-422 BDO is the
major product.
Example XVI
BDO Strains Expression Phosphoenolpyruvate Carboxykinase
[0510] This example describes the utilization of
phosphoenolpyruvate carboxykinase (PEPCK) to enhance BDO
production. The Haemophilus influenza PEPCK gene was used for
heterologous expression.
[0511] Computationally, it was demonstrated that the ATP-generating
conversion of oxaloacetate to phosphoenolpyruvate is required to
reach the maximum theoretical yield of 1,4-butanediol (see also
WO2008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S.
publication 2009/0075351). Lack of PEPCK activity was shown to
reduce the maximum theoretical yield of BDO by 12% assuming
anaerobic conditions and by 3% assuming an external electron
acceptor such as nitrate or oxygen is present.
[0512] In organisms such as E. coli, PEPCK operates in the
gluconeogenic and ATP-consuming direction from oxaloacetate towards
phosphoenolpyruvate. It has been hypothesized that kinetic
limitations of PEPCK of E. coli prevent it from effectively
catalyzing the formation of oxaloacetate from PEP. PEP carboxylase
(PPC), which does not generate ATP but is required for efficient
growth, is naturally utilized by E. coli to form oxaloacetate from
phosphoenolpyruvate. Therefore, three non native PEPCK enzymes
(Table 26) were tested for their ability to complement growth of a
PPC mutant strain of E. coli in glucose minimal media.
TABLE-US-00077 TABLE 26 Sources of phosphoenolpyruvate
carboxykinase sequences. Accession Number, PEPCK Source Strain
GenBank Reference Sequence Haemophilus influenza NC_000907.1
Actinobacillus succinogenes YP_001343536.1 Mannheimia
succiniciproducens YP_089485.1
[0513] Growth complementation studies involved plasmid based
expression of the candidate genes in .DELTA.ppc mutant E. coli
JW3978 obtained from the Keio collection (Baba et al., Molecular
Systems Biology 2:2006.0008 (2006)). The genes were cloned behind
the PA1lacO-1 promoter in the expression vectors pZA23 (medium
copy) and pZE13 (high copy). These plasmids have been described
previously (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210
(1997)), and their use in expression BDO pathway genes has been
described previously in WO2008115840.
[0514] Pre-cultures were grown aerobically in M9 minimal media with
4 g/L glucose. All pre-cultures were supplemented with aspartate (2
mM) to provide the .DELTA.ppc mutants with a source for generating
TCA cycle intermediates independent of PEPCK expression. M9 minimal
media was also used in the test conditions with 4 g/L glucose, but
no aspartate was added and IPTG was added to 0.5 mM. Table 27 shows
the results of the growth complementation studies.
TABLE-US-00078 TABLE 27 Complementation of .DELTA.ppc mutants with
PEPCK from H. influenzae, A. succinogenes and M. succinoproducens
when expressed from vectors pZA23 or pZE13. PEPCK Source Strain
Vector Time (h) OD.sub.600 H. influenzae pZA23BB 40 0.950
.DELTA.ppc Control pZA23BB 40 0.038 A. succinogenes pZA23BB 40
0.055 M. succinoproducens pZA23BB 40 0.214 A. succinogenes pZE13BB
40 0.041 M. succinoproducens pZE13BB 40 0.024 .DELTA.ppc Control
pZE13BB 40 0.042
[0515] Haemophilus influenza PEPCK was found to complement growth
in .DELTA.ppc mutant E. coli best among the genes that were tested
in the plasmid based screening. This gene was then integrated into
the PPC locus of wild-type E. coli (MG1655) using the SacB counter
selection method with pRE118-V2 discussed above (Gay et al., J.
Bacteriol. 153:1424-1431 (1983)). PEPCK was integrated retaining
the E. coli native PPC promoter, but utilizing the non-native PEPCK
terminator. The sequence of this region following replacement of
ppc by H. influenzae pepck is shown in FIG. 48. The pepck coding
region is underlined.
[0516] Techniques for adaptive evolution were applied to improve
the growth rate of the E. coli mutant (.DELTA.ppc::H. inf pepCK).
M9 minimal media with 4 g/L glucose and 50 mM sodium bicarbonate
was used to culture and evolve this strain in an anaerobic
environment. The high sodium bicarbonate concentration was used to
drive the equilibrium of the PEPCK reaction toward oxaloacetate
formation. To maintain exponential growth, the culture was diluted
2-fold whenever an OD600 of 0.5 was achieved. After about 100
generations over 3 weeks of adaptive evolution, anaerobic growth
rates improved from about 8 h to that of wild type, about 2 h.
Following evolution, individual colonies were isolated, and growth
in anaerobic bottles was compared to that of the initial mutant and
wild-type strain (see FIG. 49). M9 medium with 4 g/L glucose and 50
mM sodium bicarbonate was used.
[0517] The ppc/pepck gene replacement procedure described above was
then repeated, this time using the BDO-producing strains ECKh-432
(.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA gltAR163L .DELTA.ackA fimD:: E. coli sucCD,
P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C.
kluyveri 4hbd) and ECKh-439 as the hosts. These strains contain the
TCA cycle enhancements discussed above as well as the upstream
pathway integrated in the chromosome. ECKh-439 is a derivative of
ECKh-432 that has the ackA gene deleted, which encodes acetate
kinase. This deletion was performed using the sacB counterselection
method described above.
[0518] The .DELTA.ppc::H. inf pepCK derivative of ECKh-439, called
ECKh-453, was run in a fermentation. The downstream BDO pathway was
supplied by pZS*13 containing P. gingivalis Cat2 and C.
beijerinckii Ald. This was performed with 1L initial culture volume
in 2L Biostat B+ bioreactors (Sartorius) using M9 minimal medium
supplemented with 20 g/L glucose and 50 mM NaHCO.sub.3. The
temperature was controlled at 37.degree. C., and the pH was
controlled at 7.0 using 2 M NH.sub.4OH or Na.sub.2CO.sub.3. Cells
were grown aerobically to an OD600 of approximately 2, at which
time the cultures were induced with 0.2 mM IPTG. One hour following
induction, the air flow rate was reduced to 0.01 standard liters
per minute for microaerobic conditions. The agitation rate was
initially set at 700 rpm. The aeration rate was gradually increased
throughout the fermentation as the culture density increased.
Concentrated glucose solution was fed to maintain glucose
concentration in the vessel between 0.5 and 10 g/L. The product
profile is shown in FIG. 50. The observed phenotype, in which BDO
and acetate are produced in approximately a one-to-one molar ratio,
is highly similar to that predicted in WO 2009/023493 for design
#439 (ADHEr, ASPT, LDH_D, MDH, PFLi). The deletion targeting the
ASPT reaction was deemed unnecessary as the natural flux through
aspartate ammonia-lyase is low.
[0519] A key feature of OptKnock strains is that production of the
metabolite of interest is generally coupled to growth, and further,
that, production should occur during exponential growth as well as
in stationary phase. The growth coupling potential of ECKh-432 and
ECKh-453 was evaluated by growth in microaerobic bottles with
frequent sampling during the exponential phase. M9 medium
containing 4 g/L glucose and either 10 mM NaHCO.sub.3 (for
ECKh-432) or 50 mM NaHCO.sub.3 (for ECKh-453) was used, and 0.2 mM
IPTG was included from inoculation. 18G needles were used for
microaerobic growth of ECKh-432, while both 18G and 27G needles
were tested for ECKh-453. The higher gauge needles result in less
aeration. As shown in FIG. 51, ECKh-432 does not begin producing
BDO until 5 g/L glucose has been consumed, corresponding to the
onset of stationary phase. ECKh-453 produces BDO more evenly
throughout the experiment. In addition, growth coupling improves as
the aeration of the culture is reduced.
Example XVII
Integration of BDO Pathway Encoding Genes at Specific Integration
Sites
[0520] This example describes integration of various BDO pathway
genes into the fimD locus to provide more efficient expression and
stability.
[0521] The entire upstream BDO pathway, leading to 4HB, has been
integrated into the E. coli chromosome at the fimD locus. The
succinate branch of the upstream pathway was integrated into the E.
coli chromosome using the .lamda. red homologeous recombination
method (Datsenko and Wanner, Proc. Natl. Acad. Sci. USA
97:6640-6645 (2000)). The recipient E. coli strain was ECKh-422
(.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA gltAR163L). A polycistronic DNA fragment
containing a promoter, the sucCD gene, the sucD gene and the 4hbd
gene and a terminator sequence was inserted into the AflIII site of
the pKD3 plasmid. The following primers were used to amplify the
operon together with the chloramphenicol marker from the plasmid.
The underlined sequences are homologeous to the target insertion
site.
TABLE-US-00079 (SEQ ID NO: 41)
5'-GTTTGCACGCTATAGCTGAGGTTGTTGTCTTCCAGCAACGTACCGTA
TACAATAGGCGTATCACGAGGCCCTTTC-3' (SEQ ID NO: 42)
5'-GCTACAGCATGTCACACGATCTCAACGGTCGGATGACCAATCTGGCT
GGTATGGGAATTAGCCATGGTCC-3'
[0522] Following DpnI treatment and DNA electrophoresis, the
purified PCR product was used to transform E. coli strain harboring
plasmid pKD46. The candidate strain was selected on plates
containing chloramphenicol. Genomic DNA of the candidate strain was
purified. The insertion sequence was amplified and confirmed by DNA
sequencing. The chloramphenicol-resistant marker was removed from
chromosome by flipase. The nucleotide sequence of the region after
insertion and marker removal is shown in FIG. 52.
[0523] The alpha-ketoglutarate branch of the upstream pathway was
integrated into the chromosome by homologeous recombination. The
plasmid used in this modification was derived from vector
pRE118-V2, as referenced in Example XIV, which contains a
kanamycin-resistant gene, a gene encoding the levansucrase (sacB)
and a R6K conditional replication ori. The integration plasmid also
contained a polycistronic sequence with a promoter, the sucA gene,
the C. kluyveri 4hbd gene, and a terminator being inserted between
two 1.5-kb DNA fragments that are homologeous to the flanking
regions of the target insertion site. The resulting plasmid was
used to transform E. coli strain. The integration candidate was
selected on plates containing kanamycin. The correct integration
site was verified by PCR. To resolve the antibiotic marker from the
chromosome, the cells were selected for growth on medium containing
sucrose. The final strain was verified by PCR and DNA sequencing.
The nucleotide sequence of the chromosomal region after insertion
and marker removal is shown in FIG. 53.
[0524] The resulting upstream pathway integration strain ECKh-432
was transformed with a plasmid harboring the downstream pathway
genes. The construct was able to produce BDO from glucose in
minimal medium (see FIG. 54).
Example XVIII
Use of a Non-Phosphotransferase Sucrose Uptake System to Reduce
Pyruvate Byproduct Formation
[0525] This example describes the utilization of a
non-phosphotransferase (PTS) sucrose uptake system to reduce
pyruvate as a byproduct in the conversion of sucrose to BDO.
[0526] Strains engineered for the utilization of sucrose via a
phosphotransferase (PTS) system produce significant amounts of
pyruvate as a byproduct. Therefore, the use of a non-PTS sucrose
system can be used to decrease pyruvate formation because the
import of sucrose would not be accompanied by the conversion of
phosphoenolpyruvate (PEP) to pyruvate. This will increase the PEP
pool and the flux to oxaloacetate through PPC or PEPCK.
[0527] Insertion of a non-PTS sucrose operon into the rrnC region
was performed. To generate a PCR product containing the non-PTS
sucrose genes flanked by regions of homology to the rrnC region,
two oligos were used to PCR amplify the csc genes from Mach1.TM.
(Invitrogen, Carlsbad, Calif.). This strain is a descendent of W
strain which is an E. coli strain known to be able to catabolize
sucrose (Orencio-Trejo et al., Biotechnology Biofuels 1:8 (2008)).
The sequence was derived from E. coli W strain KO11 (accession
AY314757) (Shukla et al., Biotechnol. Lett. 26:689-693 (2004)) and
includes genes encoding a sucrose permease (cscB), D-fructokinase
(cscK), sucrose hydrolase (cscA), and a LacI-related
sucrose-specific repressor (cscR). The first 53 amino acids of cscR
was effectively removed by the placement of the AS primer. The
sequences of the oligos were: rrnC 23S del S-CSC 5'-TGT GAG TGA AAG
TCA CCT GCC TTA ATA TCT CAA AAC TCA TCT TCG GGT GAC GAA ATA TGG CGT
GAC TCG ATA C-3' (SEQ ID NO:43) and rrnC 23S del AS-CSC 5'-TCT GTA
TCA GGC TGA AAA TCT TCT CTC ATC CGC CAA AAC AGC TTC GGC GTT AAG ATG
CGC GCT CAA GGA C-3' (SEQ ID NO:44). Underlined regions indicate
homology to the csc operon, and bold sequence refers to sequence
homology upstream and downstream of the rrnC region. The sequence
of the entire PCR product is shown in FIG. 55.
[0528] After purification, the PCR product was electroporated into
MG1655 electrocompetent cells which had been transformed with
pRedET (tet) and prepared according to manufacturer's instructions
(genebridges.com/gb/pdf/K001%20Q%20E%20BAC%20Modification%20Kit-version2.-
6-2007-screen.pdf). The PCR product was designed so that it
integrated into genome into the rrnC region of the chromosome. It
effectively deleted 191 nucleotides upstream of rrlC (23S rRNA),
all of the rrlC rRNA gene and 3 nucleotides downstream of rrlC and
replaced it with the sucrose operon, as shown in FIG. 56.
[0529] Transformants were grown on M9 minimal salts medium with
0.4% sucrose and individual colonies tested for presence of the
sucrose operon by diagnostic PCR. The entire rrnC::crcAKB region
was transferred into the BDO host strain ECKh-432 by P1
transduction (Sambrook et al., Molecular Cloning: A Laboratory
Manual, Third Ed., Cold Spring Harbor Laboratory, New York (2001),
resulting in ECKh-463 (.DELTA.adhE .DELTA.ldhA .DELTA.pflB
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA gltAR163L fimD:: E.
coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis
sucA, C. kluyveri 4hbd rrnC::cscAKB). Recombinants were selected by
growth on sucrose and verified by diagnostic PCR.
[0530] ECKh-463 was transformed with pZS*13 containing P.
gingivalis Cat2 and C. beijerinckii Ald to provide a complete BDO
pathway. Cells were cultured in M9 minimal medium (6.78 g/L
Na.sub.2HPO.sub.4, 3.0 g/L KH.sub.2PO.sub.4, 0.5 g/L NaCl, 1.0 g/L
NH.sub.4Cl, 1 mM MgSO.sub.4, 0.1 mM CaCl.sub.2) supplemented with
10 g/L sucrose. 0.2 mM IPTG was present in the culture from the
start. Anaerobic conditions were maintained using a bottle with 23G
needle. As a control, ECKh-432 containing the same plasmid was
cultured on the same medium, except with 10 g/L glucose instead of
sucrose. FIG. 57 shows average product concentration, normalized to
culture OD600, after 48 hours of growth. The data is for 6
replicate cultures of each strain. This demonstrates that BDO
production from ECKh-463 on sucrose is similar to that of the
parent strain on sucrose.
Example XIX
Summary of BDO Producing Strains
[0531] This example describes various BDO producing strains.
[0532] Table 28 summarizes various BDO producing strains disclosed
above in Examples XII-XVIII.
TABLE-US-00080 TABLE 28 Summary of various BDO production strains.
Host Host Host Strain # Strain # chromosome Description
Plasmid-based 1 .DELTA.ldhA Single deletion E. coli sucCD, P.
gingivalis derivative of E. coli sucD, P. gingivalis 4hbd, MG1655
P. gingivalis Cat2, C. acetobutylicum AdhE2 2 AB3 .DELTA.adhE
.DELTA.ldhA .DELTA.pflB Succinate producing E. coli sucCD, P.
gingivalis strain; derivative of sucD, P. gingivalis 4hbd, E. coli
MG1655 P. gingivalis Cat2, C. acetobutylicum AdhE2 3 ECKh-138
.DELTA.adhE .DELTA.ldhA .DELTA.pflB Improvement of E. coli sucCD,
P. gingivalis .DELTA.lpdA::K.p.lpdA322 lpdA to increase sucD, P.
gingivalis 4hbd, pyruvate P. gingivalis Cat2, dehydrogenase flux C.
acetobutylicum AdhE2 4 ECKh-138 .DELTA.adhE .DELTA.ldhA .DELTA.pflB
E. coli sucCD, P. gingivalis .DELTA.lpdA::K.p.lpdA322 sucD, P.
gingivalis 4hbd, C. acetobutylicum buk1, C. acetobutylicum ptb, C.
acetobutylicum AdhE2 5 ECKh-401 .DELTA.adhE .DELTA.ldhA .DELTA.pflB
Deletions in mdh and E. coli sucCD, P. gingivalis
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA arcA to direct flux
sucD, P. gingivalis 4hbd, through oxidative P. gingivalis Cat2, TCA
cycle C. acetobutylicum AdhE2 6 ECKh-401 .DELTA.adhE .DELTA.ldhA
.DELTA.pflB M. bovis sucA, E. coli sucCD, .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA P. gingivalis sucD, P. gingivalis 4hbd, P.
gingivalis Cat2, C. acetobutylicum AdhE2 7 ECKh-422 .DELTA.adhE
.DELTA.ldhA .DELTA.pflB Mutation in citrate E. coli sucCD, P.
gingivalis .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA synthase
to improve sucD, P. gingivalis 4hbd, gltAR163L anaerobic activity
P. gingivalis Cat2, C. acetobutylicum AdhE2 8 ECKh-422 .DELTA.adhE
.DELTA.ldhA .DELTA.pflB M. bovis sucA, E. coli sucCD,
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA P. gingivalis sucD,
gltAR163L P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum
AdhE2 9 ECKh-422 .DELTA.adhE .DELTA.ldhA .DELTA.pflB M. bovis sucA,
E. coli sucCD, .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA P.
gingivalis sucD, gltAR163L P. gingivalis 4hbd, P. gingivalis Cat2,
C. beijerinckii Ald 10 ECKh-426 .DELTA.adhE .DELTA.ldhA .DELTA.pflB
Succinate branch of P. gingivalis Cat2, .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA upstream pathway C. beijerinckii Ald
gltAR163L fimD:: E. coli sucCD, integrated into P. gingivalis sucD,
P. gingivalis 4hbd ECKh-422 11 ECKh-432 .DELTA.adhE .DELTA.ldhA
.DELTA.pflB Succinate and alpha- P. gingivalis Cat2,
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA ketoglutarate C.
beijerinckii Ald gltAR163L fimD:: E. coli sucCD, upstream pathway
P. gingivalis sucD, P. gingivalis 4hbd branches integrated fimD::
M. bovis sucA, C. kluyveri into ECKh-422 4hbd 12 ECKh-432
.DELTA.adhE .DELTA.ldhA .DELTA.pflB C. acetobutylicum buk1,
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA C. acetobutylicum
ptb, gltAR163L fimD:: E. coli sucCD, C. beijerinckii Ald P.
gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C.
kluyveri 4hbd 13 ECKh-439 .DELTA.adhE .DELTA.ldhA .DELTA.pflB
Acetate kinase P. gingivalis Cat2, .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh .DELTA.arcA deletion of ECKh- C. beijerinckii Ald
gltAR163L .DELTA.ackA fimD:: E. coli 432 sucCD, P. gingivalis sucD,
P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd 14
ECKh-453 .DELTA.adhE .DELTA.ldhA .DELTA.pflB Acetate kinase P.
gingivalis Cat2, .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh .DELTA.arcA
deletion and C. beijerinckii Ald gltAR163L .DELTA.ackA
.DELTA.ppc::H.i.ppck PPC/PEPCK fimD:: E. coli sucCD, P. gingivalis
replacement of sucD, P. gingivalis 4hbd fimD:: ECKh-432 M. bovis
sucA, C. kluyveri 4hbd 15 ECKh-456 .DELTA.adhE .DELTA.ldhA
.DELTA.pflB .DELTA.lpdA::fnr-pflB6- Replacement of lpdA P.
gingivalis Cat2, K.p.lpdA322 .DELTA.mdh .DELTA.arcA gltAR163L
promoter with C. beijerinckii Ald fimD:: E. coli sucCD, P.
gingivalis anaerobic promoter sucD, P. gingivalis 4hbd fimD:: in
ECKh-432 M. bovis sucA, C. kluyveri 4hbd 16 ECKh-455 .DELTA.adhE
.DELTA.ldhA .DELTA.pflB .DELTA.lpdA:: Replacement of P. gingivalis
Cat2, K.p.lpdA322 .DELTA.pdhR:: fnr-pflB6 .DELTA.mdh pdhR and aceEF
C. beijerinckii Ald .DELTA.arcA gltAR163L fimD:: E. coli promoter
with sucCD, P. gingivalis sucD, anaerobic promoter P. gingivalis
4hbd fimD:: M. bovis sucA, in ECKh-432 C. kluyveri 4hbd 17 ECKh-459
.DELTA.adhE .DELTA.ldhA .DELTA.pflB .DELTA.lpdA:: Integration of C.
beijerinckii Ald K.p.lpdA322 .DELTA.mdh .DELTA.arcA gltAR163L
BK/PTB into ECKh- fimD:: E. coli sucCD, P. gingivalis 432 sucD, P.
gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd fimD:: C.
acetobutylicum buk1, C. acetobutylicum ptb 18 ECKh-459 .DELTA.adhE
.DELTA.ldhA .DELTA.pflB .DELTA.lpdA:: C. beijerinckii Ald,
K.p.lpdA322 .DELTA.mdh .DELTA.arcA gltAR163L G. thermoglucosidasius
adh1 fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd
fimD:: M. bovis sucA, C. kluyveri 4hbd fimD:: C. acetobutylicum
buk1, C. acetobutylicum ptb 19 ECKh-463 .DELTA.adhE .DELTA.ldhA
.DELTA.pflB Non-PTS sucrose P. gingivalis Cat2,
.DELTA.lpdA::K.p.lpdA322 .DELTA.mdh genes inserted into C.
beijerinckii Ald .DELTA.arcA gltAR163L fimD:: E. coli ECKh-432
sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA,
C. kluyveri 4hbd rrnC::cscAKB 20 ECKh-463 .DELTA.adhE .DELTA.ldhA
.DELTA.pflB C. acetobutylicum buk1, .DELTA.lpdA::K.p.lpdA322
.DELTA.mdh C. acetobutylicum ptb, .DELTA.arcA gltAR163L fimD:: E.
coli C. beijerinckii Ald sucCD, P. gingivalis sucD, P. gingivalis
4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd rrnC::cscAKB
[0533] The strains summarized in Table 28 are as follows. Strain 1:
Single deletion derivative of E. coli MG1655, with deletion of
endogenous ldhA; plasmid expression of E. coli sucCD, P. gingivalis
sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum
AdhE2. Strain 2: Host strain AB3, a succinate producing strain,
derivative of E. coli MG1655, with deletions of endogenous adhE
ldhA pflB; plasmid expression of E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum
AdhE2.
[0534] Strain 3: Host strain ECKh-138, deletion of endogenous adhE,
ldhA, pflB, deletion of endogenous lpdA and chromosomal insertion
of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA
locus; plasmid expression of E. coli sucCD, P. gingivalis sucD, P.
gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2;
strain provides improvement of lpdA to increase pyruvate
dehydrogenase flux. Strain 4: Host strain ECKh-138, deletion of
endogenous adhE, ldhA, pflB, and lpdA, chromosomal insertion of
Klebsiella pneumoniae lpdA with a Glu354Lys mutation; plasmid
expression E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd,
C. acetobutylicum buk1, C. acetobutylicum ptb, C. acetobutylicum
AdhE2.
[0535] Strain 5: Host strain ECKh-401, deletion of endogenous adhE,
ldhA, pflB, deletion of endogenous lpdA and chromosomal insertion
of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA
locus, deletion of endogenous mdh and arcA; plasmid expression of
E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P.
gingivalis Cat2, C. acetobutylicum AdhE2; strain has deletions in
mdh and arcA to direct flux through oxidative TCA cycle. Strain 6:
host strain ECKh-401, deletion of endogenous adhE, ldhA, pflB,
deletion of endogenous lpdA and chromosomal insertion of Klebsiella
pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus,
deletion of endogenous mdh and arcA; plasmid expression of M. bovis
sucA, E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P.
gingivalis Cat2, C. acetobutylicum AdhE2.
[0536] Strain 7: Host strain ECKh-422, deletion of endogenous adhE,
ldhA, pflB, deletion of endogenous lpdA and chromosomal insertion
of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA
locus, deletion of endogenous mdh and arcA, chromosomal replacement
of gltA with gltA Arg163Leu mutant; plasmid expression of E. coli
sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2,
C. acetobutylicum AdhE2; strain has mutation in citrate synthase to
improve anaerobic activity. Strain 8: strain ECKh-422, deletion of
endogenous adhE, ldhA, pflB, deletion of endogenous lpdA and
chromosomal insertion of Klebsiella pneumoniae lpdA with a
Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh
and arcA, chromosomal replacement of gltA with gltA Arg163Leu
mutant; plasmid expression of M. bovis sucA, E. coli sucCD, P.
gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C.
acetobutylicum AdhE2. Strain 9: host strain ECKh-422, deletion of
endogenous adhE, ldhA, pflB, deletion of endogenous lpdA and
chromosomal insertion of Klebsiella pneumoniae lpdA with a
Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh
and arcA, chromosomal replacement of gltA with gltA Arg163Leu
mutant; plasmid expression of M. bovis sucA, E. coli sucCD, P.
gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C.
beijerinckii Ald.
[0537] Strain 10: host strain ECKh-426, deletion of endogenous
adhE, ldhA, pflB, deletion of endogenous lpdA and chromosomal
insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation
at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal
replacement of gltA with gltA Arg163Leu mutant, chromosomal
insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd; plasmid expression of P. gingivalis Cat2, C.
beijerinckii Ald; strain has succinate branch of upstream pathway
integrated into strain ECKh-422 at the fimD locus. Strain 11: host
strain ECKh-432, deletion of endogenous adhE, ldhA, pflB, deletion
of endogenous lpdA and chromosomal insertion of Klebsiella
pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus,
deletion of endogenous mdh and arcA, chromosomal replacement of
gltA with gltA Arg163Leu mutant, chromosomal insertion at the fimD
locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd,
chromosomal insertion at the fimD locus of M. bovis sucA, C.
kluyveri 4hbd; plasmid expression of P. gingivalis Cat2, C.
beijerinckii Ald; strain has succinate and alpha-ketoglutarate
upstream pathway branches integrated into ECKh-422. Strain 12: host
strain ECKh-432, deletion of endogenous adhE, ldhA, pflB, deletion
of endogenous lpdA and chromosomal insertion of Klebsiella
pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus,
deletion of endogenous mdh and arcA, chromosomal replacement of
gltA with gltA Arg163Leu mutant, chromosomal insertion at the fimD
locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd,
chromosomal insertion at the fimD locus of M. bovis sucA, C.
kluyveri 4hbd; plasmid expression of C. acetobutylicum buk1, C.
acetobutylicum ptb, C. beijerinckii Ald.
[0538] Strain 13: host strain ECKh-439, deletion of endogenous
adhE, ldhA, pflB, deletion of endogenous lpdA and chromosomal
insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation
at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal
replacement of gltA with gltA Arg163Leu mutant, deletion of
endogenous ackA, chromosomal insertion at the fimD locus of E. coli
sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal
insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd;
plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald;
strain has acetate kinase deletion in strain ECKh-432. Strain 14:
host strain ECKh-453, deletion of endogenous adhE, ldhA, pflB,
deletion of endogenous lpdA and chromosomal insertion of Klebsiella
pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus,
deletion of endogenous mdh and arcA, chromosomal replacement of
gltA with gltA Arg163Leu mutant, deletion of endogenous ackA,
deletion of endogenous ppc and insertion of Haemophilus influenza
ppck at the ppc locus, chromosomal insertion at the fimD locus of
E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal
insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd;
plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald;
strain has acetate kinase deletion and PPC/PEPCK replacement in
strain ECKh-432.
[0539] Strain 15: host strain ECKh-456, deletion of endogenous
adhE, ldhA, pflB, deletion of endogenous lpdA and chromosomal
insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation
at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal
replacement of gltA with gltA Arg163Leu mutant, chromosomal
insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M.
bovis sucA, C. kluyveri 4hbd, replacement of lpdA promoter with fnr
binding site, pflB-p6 promoter and RBS of pflB; plasmid expression
of P. gingivalis Cat2, C. beijerinckii Ald; strain has replacement
of lpdA promoter with anaerobic promoter in strain ECKh-432. Strain
16: host strain ECKh-455, deletion of endogenous adhE, ldhA, pflB,
deletion of endogenous lpdA and chromosomal insertion of Klebsiella
pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus,
deletion of endogenous mdh and arcA, chromosomal replacement of
gltA with gltA Arg163Leu mutant, chromosomal insertion at the fimD
locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd,
chromosomal insertion at the fimD locus of M. bovis sucA, C.
kluyveri 4hbdI, replacement of pdhR and aceEF promoter with fnr
binding site, pflB-p6 promoter and RBS of pflB; plasmid expression
of P. gingivalis Cat2, C. beijerinckii Ald; strain has replacement
of pdhR and aceEF promoter with anaerobic promoter in ECKh-432.
[0540] Strain 17: host strain ECKh-459, deletion of endogenous
adhE, ldhA, pflB, deletion of endogenous lpdA and chromosomal
insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation
at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal
replacement of gltA with gltA Arg163Leu mutant, chromosomal
insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M.
bovis sucA, C. kluyveri 4hbd, chromosomal insertion at the fimD
locus of C. acetobutylicum buk1, C. acetobutylicum ptb; plasmid
expression of C. beijerinckii Ald; strain has integration of BK/PTB
into strain ECKh-432. Strain 18: host strain ECKh-459, deletion of
endogenous adhE, ldhA, pflB, deletion of endogenous lpdA and
chromosomal insertion of Klebsiella pneumoniae lpdA with a
Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh
and arcA, chromosomal replacement of gltA with gltA Arg163Leu
mutant, chromosomal insertion at the fimD locus of E. coli sucCD,
P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at
the fimD locus of M. bovis sucA, C. kluyveri 4hbd, chromosomal
insertion at the fimD locus of C. acetobutylicum buk1, C.
acetobutylicum ptb; plasmid expression of C. beijerinckii Ald, G.
thermoglucosidasius adh1.
[0541] Strain 19: host strain ECKh-463, deletion of endogenous
adhE, ldhA, pflB, deletion of endogenous lpdA and chromosomal
insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation
at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal
replacement of gltA with gltA Arg163Leu mutant, chromosomal
insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD,
P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M.
bovis sucA, C. kluyveri 4hbd, insertion at the rrnC locus of
non-PTS sucrose operon genes sucrose permease (cscB),
D-fructokinase (cscK), sucrose hydrolase (cscA), and a LacI-related
sucrose-specific repressor (cscR); plasmid expression of P.
gingivalis Cat2, C. beijerinckii Ald; strain has non-PTS sucrose
genes inserted into strain ECKh-432. Strain 20: host strain
ECKh-463 deletion of endogenous adhE, ldhA, pflB, deletion of
endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae
lpdA with a Glu354Lys mutation at the lpdA locus, deletion of
endogenous mdh and arcA, chromosomal replacement of gltA with gltA
Arg163Leu mutant, chromosomal insertion at the fimD locus of E.
coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal
insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd,
insertion at the rrnC locus of non-PTS sucrose operon; plasmid
expression of C. acetobutylicum buk1, C. acetobutylicum ptb, C.
beijerinckii Ald.
[0542] In addition to the BDO producing strains disclosed herein,
including those disclosed in Table 28, it is understood that
additional modifications can be incorporated that further increase
production of BDO and/or decrease undesirable byproducts. For
example, a BDO producing strain, or a strain of Table 28, can
incorporate additional knockouts to further increase the production
of BDO or decrease an undesirable byproduct. Exemplary knockouts
have been described previously (see U.S. publication 2009/0047719).
Such knockout strains include, but are not limited to, ADHEr,
NADH6; ADHEr, PPCK; ADHEr, SUCD4; ADHEr, ATPS4r; ADHEr, FUM; ADHEr,
MDH; ADHEr, PFLi, PPCK; ADHEr, PFLi, SUCD4; ADHEr, ACKr, NADH6;
ADHEr, NADH6, PFLi; ADHEr, ASPT, MDH; ADHEr, NADH6, PPCK; ADHEr,
PPCK, THD2; ADHEr, ATPS4r, PPCK; ADHEr, MDH, THD2; ADHEr, FUM,
PFLi; ADHEr, PPCK, SUCD4; ADHEr, GLCpts, PPCK; ADHEr, GLUDy, MDH;
ADHEr, GLUDy, PPCK; ADHEr, FUM, PPCK; ADHEr, MDH, PPCK; ADHEr, FUM,
GLUDy; ADHEr, FUM, HEX1; ADHEr, HEX1, PFLi; ADHEr, HEX1, THD2;
ADHEr, FRD2, LDH_D, MDH; ADHEr, FRD2, LDH_D, ME2; ADHEr, MDH, PGL,
THD2; ADHEr, G6PDHy, MDH, THD2; ADHEr, PFLi, PPCK, THD2; ADHEr,
ACKr, AKGD, ATPS4r; ADHEr, GLCpts, PFLi, PPCK; ADHEr, ACKr, ATPS4r,
SUCOAS; ADHEr, GLUDy, PFLi, PPCK; ADHEr, ME2, PFLi, SUCD4; ADHEr,
GLUDy, PFLi, SUCD4; ADHEr, ATPS4r, LDH_D, SUCD4; ADHEr, FUM, HEX1,
PFLi; ADHEr, MDH, NADH6, THD2; ADHEr, ATPS4r, MDH, NADH6; ADHEr,
ATPS4r, FUM, NADH6; ADHEr, ASPT, MDH, NADH6; ADHEr, ASPT, MDH,
THD2; ADHEr, ATPS4r, GLCpts, SUCD4; ADHEr, ATPS4r, GLUDy, MDH;
ADHEr, ATPS4r, MDH, PPCK; ADHEr, ATPS4r, FUM, PPCK; ADHEr, ASPT,
GLCpts, MDH; ADHEr, ASPT, GLUDy, MDH; ADHEr, ME2, SUCD4, THD2;
ADHEr, FUM, PPCK, THD2; ADHEr, MDH, PPCK, THD2; ADHEr, GLUDy, MDH,
THD2; ADHEr, HEX1, PFLi, THD2; ADHEr, ATPS4r, G6PDHy, MDH; ADHEr,
ATPS4r, MDH, PGL; ADHEr, ACKr, FRD2, LDH_D; ADHEr, ACKr, LDH_D,
SUCD4; ADHEr, ATPS4r, FUM, GLUDy; ADHEr, ATPS4r, FUM, HEX1; ADHEr,
ATPS4r, MDH, THD2; ADHEr, ATPS4r, FRD2, LDH_D; ADHEr, ATPS4r, MDH,
PGDH; ADHEr, GLCpts, PPCK, THD2; ADHEr, GLUDy, PPCK, THD2; ADHEr,
FUM, HEX1, THD2; ADHEr, ATPS4r, ME2, THD2; ADHEr, FUM, ME2, THD2;
ADHEr, GLCpts, GLUDy, PPCK; ADHEr, ME2, PGL, THD2; ADHEr, G6PDHy,
ME2, THD2; ADHEr, ATPS4r, FRD2, LDH_D, ME2; ADHEr, ATPS4r, FRD2,
LDH_D, MDH; ADHEr, ASPT, LDH_D, MDH, PFLi; ADHEr, ATPS4r, GLCpts,
NADH6, PFLi; ADHEr, ATPS4r, MDH, NADH6, PGL; ADHEr, ATPS4r, G6PDHy,
MDH, NADH6; ADHEr, ACKr, FUM, GLUDy, LDH_D; ADHEr, ACKr, GLUDy,
LDH_D, SUCD4; ADHEr, ATPS4r, G6PDHy, MDH, THD2; ADHEr, ATPS4r, MDH,
PGL, THD2; ADHEr, ASPT, G6PDHy, MDH, PYK; ADHEr, ASPT, MDH, PGL,
PYK; ADHEr, ASPT, LDH_D, MDH, SUCOAS; ADHEr, ASPT, FUM, LDH_D, MDH;
ADHEr, ASPT, LDH_D, MALS, MDH; ADHEr, ASPT, ICL, LDH_D, MDH; ADHEr,
FRD2, GLUDy, LDH_D, PPCK; ADHEr, FRD2, LDH_D, PPCK, THD2; ADHEr,
ACKr, ATPS4r, LDH_D, SUCD4; ADHEr, ACKr, ACS, PPC, PPCK; ADHEr,
GLUDy, LDH_D, PPC, PPCK; ADHEr, LDH_D, PPC, PPCK, THD2; ADHEr,
ASPT, ATPS4r, GLCpts, MDH; ADHEr, G6PDHy, MDH, NADH6, THD2; ADHEr,
MDH, NADH6, PGL, THD2; ADHEr, ATPS4r, G6PDHy, GLCpts, MDH; ADHEr,
ATPS4r, GLCpts, MDH, PGL; ADHEr, ACKr, LDH_D, MDH, SUCD4.
[0543] Table 29 shows the reactions of corresponding genes to be
knocked out of a host organism such as E. coli. The corresponding
metabolite corresponding to abbreviations in Table 29 are shown in
Table 30.
TABLE-US-00081 TABLE 29 Corresponding genes to be knocked out to
prevent a particular reaction from occurring in E. coli. Reaction
Reaction Genes Encoding the Enzyme(s) Abbreviation Stoichiometry*
Catalyzing Each Reaction& ACKr [c]: ac + atp <==> actp +
adp (b3115 or b2296 or b1849) ACS [c]: ac + atp + coa --> accoa
+ amp + ppi b4069 ACt6 ac[p] + h[p] <==> ac[c] + h[c]
Non-gene associated ADHEr [c]: etoh + nad <==> acald + h +
nadh (b0356 or b1478 or b1241) [c]: acald + coa + nad <==>
accoa + h + nadh (b1241 or b0351) AKGD [c]: akg + coa + nad -->
co2 + nadh + succoa (b0116 and b0726 and b0727) ASNS2 [c]: asp-L +
atp + nh4 --> amp + asn-L + h + ppi b3744 ASPT [c]: asp-L -->
fum + nh4 b4139 ATPS4r adp[c] + (4) h[p] + pi[c] <==> atp[c]
+ (3) h[c] + h2o[c] (((b3736 and b3737 and b3738) and (b3731 and
b3732 and b3733 and b3734 and b3735)) or ((b3736 and b3737 and
b3738) and (b3731 and b3732 and b3733 and b3734 and b3735) and
b3739)) CBMK2 [c]: atp + co2 + nh4 <==> adp + cbp + (2) h
(b0521 or b0323 or b2874) EDA [c]: 2ddg6p --> g3p + pyr b1850
ENO [c]: 2pg <==> h2o + pep b2779 FBA [c]: fdp <==>
dhap + g3p (b2097 or b2925 or b1773) FBP [c]: fdp + h2o --> f6p
+ pi (b4232 or b3925) FDH2 for[p] + (2) h[c] + q8[c] --> co2[c]
+ h[p] + q8h2[c] ((b3892 and b3893 and b3894) for[p] + (2) h[c] +
mqn8[c] --> co2[c] + h[p] + mql8[c] or (b1474 and b1475 and
b1476)) FRD2 [c]: fum + mql8 --> mqn8 + succ (b4151 and b4152
and b4153 [c]: 2dmmql8 + fum --> 2dmmq8 + succ and b4154) FTHFD
[c]: 10fthf + h2o --> for + h + thf b1232 FUM [c]: fum + h2o
<==> mal-L (b1612 or b4122 or b1611) G5SD [c]: glu5p + h +
nadph --> glu5sa + nadp + pi b0243 G6PDHy [c]: g6p + nadp
<==> 6pgl + h + nadph b1852 GLCpts glc-D[p] + pep[c] -->
g6p[c] + pyr[c] ((b2417 and b1101 and b2415 and b2416) or (b1817
and b1818 and b1819 and b2415 and b2416) or (b2417 and b1621 and
b2415 and b2416)) GLU5K [c]: atp + glu-L --> adp + glu5p b0242
GLUDy [c]: glu-L + h2o + nadp <==> akg + h + nadph + nh4
b1761 GLYCL [c]: gly + nad + thf --> co2 + mlthf + nadh + nh4
(b2904 and b2903 and b2905 and b0116) HEX1 [c]: atp + glc-D -->
adp + g6p + h b2388 ICL [c]: icit --> glx + succ b4015 LDH_D
[c]: lac-D + nad <==> h + nadh + pyr (b2133 or b1380) MALS
[c]: accoa + glx + h2o --> coa + h + mal-L (b4014 or b2976) MDH
[c]: mal-L + nad <==> h + nadh + oaa b3236 ME2 [c]: mal-L +
nadp --> co2 + nadph + pyr b2463 MTHFC [c]: h2o + methf
<==> 10fthf + h b0529 NADH12 [c]: h + mqn8 + nadh --> mql8
+ nad b1109 [c]: h + nadh + q8 --> nad + q8h2 [c]: 2dmmq8 + h +
nadh --> 2dmmql8 + nad NADH6 (4) h[c] + nadh[c] + q8[c] -->
(3) h[p] + nad[c] + q8h2[c] (b2276 and b2277 and b2278 (4) h[c] +
mqn8[c] + nadh[c] --> (3) h[p] + mql8[c] + and b2279 and b2280
and nad[c] b2281 and b2282 and b2283 2dmmq8[c] + (4) h[c] + nadh[c]
--> 2dmmql8[c] + (3) and b2284 and b2285 and h[p] + nad[c] b2286
and b2287 and b2288) PFK [c]: atp + f6p --> adp + fdp + h (b3916
or b1723) PFLi [c]: coa + pyr --> accoa + for (((b0902 and
b0903) and b2579) or (b0902 and b0903) or (b0902 and b3114) or
(b3951 and b3952)) PGDH [c]: 6pgc + nadp --> co2 + nadph +
ru5p-D b2029 PGI [c]: g6p <==> f6p b4025 PGL [c]: 6pgl + h2o
--> 6pgc + h b0767 PGM [c]: 2pg <==> 3pg (b3612 or b4395
or b0755) PPC [c]: co2 + h2o + pep --> h + oaa + pi b3956 PPCK
[c]: atp + oaa --> adp + co2 + pep b3403 PRO1z [c]: fad + pro-L
--> 1pyr5c + fadh2 + h b1014 PYK [c]: adp + h + pep --> atp +
pyr b1854 or b1676) PYRt2 h[p] + pyr[p] <==> h[c] + pyr[c]
Non-gene associated RPE [c]: ru5p-D <==> xu5p-D (b4301 or
b3386) SO4t2 so4[e] <==> so4[p] (b0241 or b0929 or b1377 or
b2215) SUCD4 [c]: q8 + succ --> fum + q8h2 (b0721 and b0722 and
b0723 and b0724) SUCOAS [c]: atp + coa + succ <==> adp + pi +
succoa (b0728 and b0729) SULabc atp[c] + h2o[c] + so4[p] -->
adp[c] + h[c] + pi[c] + ((b2422 and b2425 and so4[c] b2424 and
b2423) or (b0763 and b0764 and b0765) or (b2422 and b2424 and b2423
and b3917)) TAL [c]: g3p + s7p <==> e4p + f6p (b2464 or
b0008) THD2 (2) h[p] + nadh[c] + nadp[c] --> (2) h[c] + nad[c] +
(b1602 and b1603) nadph[c] THD5 [c]: nad + nadph --> nadh + nadp
(b3962 or (b1602 and b1603)) TPI [c]: dhap <==> g3p b3919
TABLE-US-00082 TABLE 30 Metabolite names corresponding to
abbreviations used in Table 29. Metabolite Metabolite Abbreviation
Name 10fthf 10-Formyltetrahydrofolate 1pyr5c
1-Pyrroline-5-carboxylate 2ddg6p 2-Dehydro-3-deoxy-D-gluconate
6-phosphate 2dmmq8 2-Demethylmenaquinone 8 2dmmql8
2-Demethylmenaquinol 8 2pg D-Glycerate 2-phosphate 3pg
3-Phospho-D-glycerate 6pgc 6-Phospho-D-gluconate 6pgl
6-phospho-D-glucono-1,5-lactone ac Acetate acald Acetaldehyde accoa
Acetyl-CoA actp Acetyl phosphate adp ADP akg 2-Oxoglutarate amp AMP
asn-L L-Asparagine asp-L L-Aspartate atp ATP cbp Carbamoyl
phosphate co2 CO2 coa Coenzyme A dhap Dihydroxyacetone phosphate
e4p D-Erythrose 4-phosphate etoh Ethanol f6p D-Fructose 6-phosphate
fad Flavin adenine dinucleotide oxidized fadh2 Flavin adenine
dinucleotide reduced fdp D-Fructose 1,6-bisphosphate for Formate
fum Fumarate g3p Glyceraldehyde 3-phosphate g6p D-Glucose
6-phosphate glc-D D-Glucose glu5p L-Glutamate 5-phosphate glu5sa
L-Glutamate 5-semialdehyde glu-L L-Glutamate glx Glyoxylate gly
Glycine h H+ h2o H2O icit Isocitrate lac-D D-Lactate mal-L L-Malate
methf 5,10-Methenyltetrahydrofolate mlthf
5,10-Methylenetetrahydrofolate mql8 Menaquinol 8 mqn8 Menaquinone 8
nad Nicotinamide adenine dinucleotide nadh Nicotinamide adenine
dinucleotide - reduced nadp Nicotinamide adenine dinucleotide
phosphate nadph Nicotinamide adenine dinucleotide phosphate -
reduced nh4 Ammonium oaa Oxaloacetate pep Phosphoenolpyruvate pi
Phosphate ppi Diphosphate pro-L L-Proline pyr Pyruvate q8
Ubiquinone-8 q8h2 Ubiquinol-8 ru5p-D D-Ribulose 5-phosphate s7p
Sedoheptulose 7-phosphate so4 Sulfate succ Succinate succoa
Succinyl-CoA thf 5,6,7,8-Tetrahydrofolate xu5p-D D-Xylulose
5-phosphate
Example XX
Exemplary Pathways for Producing BDO
[0544] This example describes exemplary pathways to produce
4-hydroxybutanal (4-HBal) and/or BDO using a carboxylic acid
reductase as a BDO pathway enzyme.
[0545] An exemplary pathway for production of BDO includes use of
an NAD+ or NADP+ aryl-aldehyde dehydrogenase (E.C.: 1.2.1.29 and
1.2.1.30) to convert 4-hydroxybutyrate to 4-hydroxybutanal and an
alcohol dehydrogenase to convert 4-hydroxybutanal to
1,4-butanediol. 4-Hydroxybutyrate can be derived from the
tricarboxylic acid cycle intermediates succinyl-CoA and/or
alpha-ketoglutarate as shown in FIG. 58.
[0546] Aryl-Aldehyde Dehydrogenase (or Carboxylic Acid
Reductase).
[0547] An aryl-aldehyde dehydrogenase, or equivalently a carboxylic
acid reductase, can be found in Nocardia iowensis. Carboxylic acid
reductase catalyzes the magnesium, ATP and NADPH-dependent
reduction of carboxylic acids to their corresponding aldehydes
(Venkitasubramanian et al., J. Biol. Chem. 282:478-485 (2007)) and
is capable of catalyzing the conversion of 4-hydroxybutyrate to
4-hydroxybutanal. This enzyme, encoded by car, was cloned and
functionally expressed in E. coli (Venkitasubramanian et al., J.
Biol. Chem. 282:478-485 (2007)). Expression of the npt gene product
improved activity of the enzyme via post-transcriptional
modification. The npt gene encodes a specific phosphopantetheine
transferase (PPTase) that converts the inactive apo-enzyme to the
active holo-enzyme. The natural substrate of this enzyme is
vanillic acid, and the enzyme exhibits broad acceptance of aromatic
and aliphatic substrates (Venkitasubramanian et al., in
Biocatalysis in the Pharmaceutical and Biotechnology Industires,
ed. R. N. Patel, Chapter 15, pp. 425-440, CRC Press LLC, Boca
Raton, Fla. (2006)).
TABLE-US-00083 Gene GenBank name GI No. Accession No. Organism car
40796035 AAR91681.1 Nocardia iowensis (sp. NRRL 5646) npt 114848891
ABI83656.1 Nocardia iowensis (sp. NRRL 5646)
[0548] Additional car and npt genes can be identified based on
sequence homology.
TABLE-US-00084 Gene GenBank name GI No. Accession No. Organism
fadD9 121638475 YP_978699.1 Mycobacterium bovis BCG BCG_2812c
121638674 YP_978898.1 Mycobacterium bovis BCG nfa20150 54023983
YP_118225.1 Nocardia farcinica IFM 10152 nfa40540 54026024
YP_120266.1 Nocardia farcinica IFM 10152 SGR_6790 182440583
YP_001828302.1 Streptomyces griseus subsp. griseus NBRC 13350
SGR_665 182434458 YP_001822177.1 Streptomyces griseus subsp.
griseus NBRC 13350 MSMEG_2956 YP_887275.1 YP_887275.1 Mycobacterium
smegmatis MC2 155 MSMEG_5739 YP_889972.1 118469671 Mycobacterium
smegmatis MC2 155 MSMEG_2648 YP_886985.1 118471293 Mycobacterium
smegmatis MC2 155 MAP1040c NP_959974.1 41407138 Mycobacterium avium
subsp. paratuberculosis K-10 MAP2899c NP_961833.1 41408997
Mycobacterium avium subsp. paratuberculosis K-10 MMAR_2117
YP_001850422.1 183982131 Mycobacterium marinum M MMAR_2936
YP_001851230.1 183982939 Mycobacterium marinum M MMAR_1916
YP_001850220.1 183981929 Mycobacterium marinum M TpauDRAFT_33060
ZP_04027864.1 227980601 Tsukamurella paurometabola DSM 20162
TpauDRAFT_20920 ZP_04026660.1 ZP_04026660.1 Tsukamurella
paurometabola DSM 20162 CPCC7001_1320 ZP_05045132.1 254431429
Cyanobium PCC7001 DDBDRAFT_0187729 XP_636931.1 66806417
Dictyostelium discoideum AX4
[0549] An additional enzyme candidate found in Streptomyces griseus
is encoded by the griC and griD genes. This enzyme is believed to
convert 3-amino-4-hydroxybenzoic acid to
3-amino-4-hydroxybenzaldehyde as deletion of either griC or griD
led to accumulation of extracellular 3-acetylamino-4-hydroxybenzoic
acid, a shunt product of 3-amino-4-hydroxybenzoic acid metabolism
(Suzuki, et al., J. Antibiot. 60(6):380-387 (2007)). Co-expression
of griC and griD with SGR_665, an enzyme similar in sequence to the
Nocardia iowensis npt, can be beneficial.
TABLE-US-00085 Gene GenBank name GI No. Accession No. Organism griC
182438036 YP_001825755.1 Streptomyces griseus subsp. griseus NBRC
13350 griD 182438037 YP_001825756.1 Streptomyces griseus subsp.
griseus NBRC 13350
[0550] An enzyme with similar characteristics, alpha-aminoadipate
reductase (AAR, EC 1.2.1.31), participates in lysine biosynthesis
pathways in some fungal species. This enzyme naturally reduces
alpha-aminoadipate to alpha-aminoadipate semialdehyde. The carboxyl
group is first activated through the ATP-dependent formation of an
adenylate that is then reduced by NAD(P)H to yield the aldehyde and
AMP. Like CAR, this enzyme utilizes magnesium and requires
activation by a PPTase. Enzyme candidates for AAR and its
corresponding PPTase are found in Saccharomyces cerevisiae (Morris
et al., Gene 98:141-145 (1991)), Candida albicans (Guo et al., Mol.
Genet. Genomics 269:271-279 (2003)), and Schizosaccharomyces pombe
(Ford et al., Curr. Genet. 28:131-137 (1995)). The AAR from S.
pombe exhibited significant activity when expressed in E. coli (Guo
et al., Yeast 21:1279-1288 (2004)). The AAR from Penicillium
chrysogenum accepts S-carboxymethyl-L-cysteine as an alternate
substrate, but did not react with adipate, L-glutamate or
diaminopimelate (Hijarrubia et al., J. Biol. Chem. 278:8250-8256
(2003)). The gene encoding the P. chrysogenum PPTase has not been
identified to date.
TABLE-US-00086 Gene GenBank name GI No. Accession No. Organism LYS2
171867 AAA34747.1 Saccharomyces cerevisiae LYS5 1708896 P50113.1
Saccharomyces cerevisiae LYS2 2853226 AAC02241.1 Candida albicans
LYS5 28136195 AAO26020.1 Candida albicans Lys1p 13124791 P40976.3
Schizosaccharomyces pombe Lys7p 1723561 Q10474.1
Schizosaccharomyces pombe Lys2 3282044 CAA74300.1 Penicillium
chrysogenum
[0551] There are several advantages of using carboxylic acid
reductase for BDO production. There are at least two advantages of
forming 4-hydroxybutanal from 4-hydroxybutyrate via a carboxylic
acid reductase compared to forming 4-hydroxybutanal from an
activated version of 4-hydroxybutyrate (for example,
4-hydroxybutyryl-CoA, 4-hydroxybutyryl-Pi) via an acyl-CoA or
acyl-phosphate reductase. First, the formation of
gamma-butyrolactone (GBL) as a byproduct is greatly reduced. It is
believed that the activated versions of 4-hydroxybutyrate cyclize
to GBL more readily than unactivated 4-hydroxybutyrate. The use of
carboxylic acid reductase eliminates the need to pass through a
free activated 4-hydroxybutyrate intermediate, thus reducing the
formation of GBL as a byproduct accompanying BDO production.
Second, the formation of ethanol as a byproduct is greatly reduced.
Ethanol is often formed in varying amounts when an aldehyde- or an
alcohol-forming 4-hydroxybutyryl-CoA reductase is used to convert
4-hydroxybutyryl-CoA to 4-hydroxybutanal or 1,4-butanediol,
respectively. This is because most, if not all, aldehyde- or
alcohol-forming 4-hydroxybutyryl-CoA reductases can accept
acetyl-CoA as a substrate in addition to 4-hydroxybutyryl-CoA.
Aldehyde-forming enzymes, for example, often catalyze the
conversion of acetyl-CoA to acetaldehyde, which is subsequently
reduced to ethanol by native or non-native alcohol dehydrogenases.
Alcohol-forming 4-hydroxybutyryl-CoA reductases that accept
acetyl-CoA as a substrate will convert acetyl-CoA directly to
ethanol. It appears that carboxylic acid reductase enzymes have far
less activity on acetyl-CoA than aldehyde- or alcohol-forming
acyl-CoA reductase enzymes, and thus their application for BDO
production results in minimal ethanol byproduct formation (see
below).
Example XXI
Biosynthesis of 1,4-Butanediol Using a Carboxylic Acid Reductase
Enzyme
[0552] This example describes the generation of a microbial
organism that produces 1,4-butanediol using a carboxylic acid
reductase enzyme.
[0553] Escherichia coli is used as a target organism to engineer
the pathway for 1,4-butanediol synthesis described in FIG. 58. E.
coli provides a good host for generating a non-naturally occurring
microorganism capable of producing 1,4-butanediol. E. coli is
amenable to genetic manipulation and is known to be capable of
producing various products, like ethanol, acetic acid, formic acid,
lactic acid, and succinic acid, effectively under various
oxygenation conditions.
[0554] Integration of 4-Hydroxybutyrate Pathway Genes into
Chromosome: Construction of ECKh-432.
[0555] The carboxylic acid reductase enzyme was expressed in a
strain of E. coli designated ECKh-432 whose construction is
described in Example XVII. This strain contained the components of
the BDO pathway, leading to 4HB, integrated into the chromosome of
E. coli at the fimD locus.
[0556] As described in Example XVII, the succinate branch of the
upstream pathway was integrated into the E. coli chromosome using
the .lamda. red homologeous recombination method (Datsenko and
Wanner, Proc. Natl. Acad. Sci. USA 97:6640-6645 (2000)). A
polycistronic DNA fragment containing a promoter, the sucCD gene of
Escherichia coli encoding succinyl-CoA ligase, the sucD gene of
Porphyromonas gingivalis encoding succinyl-CoA reductase (aldehyde
forming) (step A of FIG. 58), the 4hbd gene of Porphyromonas
gingivalis encoding 4-hydroxybutyrate dehydrogenase (step C of FIG.
58), and a terminator sequence was inserted into the AflIII site of
the pKD3 plasmid.
[0557] As described in Example XVII, the alpha-ketoglutarate branch
of the upstream pathway was integrated into the chromosome by
homologeous recombination. The plasmid used in this modification
was pRE118-V2 (pRE118 (ATCC87693) deleted of the oriT and IS
sequences), which contains a kanamycin-resistant gene, a gene
encoding the levansucrase (sacB) and a R6K conditional replication
ori. The integration plasmid also contained a polycistronic
sequence with a promoter, the sucA gene from Mycobacterium bovis
encoding alpha-ketoglutarate decarboxylase (step B of FIG. 58), the
Clostridium kluyveri 4hbd gene encoding 4-hydroxybutyrate
dehydrogenase (step C of FIG. 58), and a terminator being inserted
between two 1.5-kb DNA fragments that are homologous to the
flanking regions of the target insertion site. The resulting
plasmid was used to transform E. coli strain. The integration
candidate was selected on plates containing kanamycin. The correct
integration site was verified by PCR. To resolve the antibiotic
marker from the chromosome, the cells were selected for growth on
medium containing sucrose. The final strain was verified by PCR and
DNA sequencing.
[0558] The recipient E. coli strain was ECKh-422 (.DELTA.adhE
.DELTA.ldhA .DELTA.pflB .DELTA.lpdA::K.p.lpdA322 .DELTA.mdh
.DELTA.arcA gltAR163L) whose construction is described in Example
XV. ECKh-422 contains a mutation gltAR163L leading to
NADH-insensitivity of citrate synthase encoded by gltA. It further
contains an NADH-insensitive version of the lpdA gene from
Klebsiella pneumonia integrated into the chromosome as described
below.
[0559] Replacement of the native lpdA was replaced with a
NADH-insensitive lpdA from Klebsiella pneumonia, as described in
Example XIV. The resulting vector was designated pRE118-V2 (see
FIG. 34).]
[0560] Cloning and Expression of Carboxylic Acid Reductase and
PPTase.
[0561] To generate an E. coli strain engineered to produce
1,4-butanediol, nucleic acids encoding a carboxylic acid reductase
and phosphopantetheine transferase are expressed in E. coli using
well known molecular biology techniques (see, for example,
Sambrook, supra, 2001; Ausubel supra, 1999). In particular, the car
(AAR91681.1) and npt (ABI83656.1) genes were cloned into the pZS*13
vector (Expressys, Ruelzheim, Germany) under the PA1/lacO promoter.
The car gene (GNM_720) was cloned by PCR from Nocardia genomic DNA.
Its nucleic acid and protein sequences are shown in FIGS. 59A and
59B, respectively.
[0562] A codon-optimized version of the npt gene (GNM_721) was
synthesized by GeneArt (Regensburg, Germany). Its nucleic acid and
protein sequences are shown in FIGS. 60A and 60B, respectively. The
resulting vector from cloning GNM_720 and GNM_721 into pZS*13 is
shown in FIG. 61.
[0563] The plasmid was transformed into ECKh-432 to express the
proteins and enzymes required for 1,4-butanediol production.
Alternate versions of the plasmid containing only GNM_720 and only
GNM_721 were also constructed.
[0564] Demonstration of 1,4-BDO Production Using Carboxylic Acid
Reductase.
[0565] Functional expression of the 1,4-butanediol pathway was
demonstrated using E. coli whole-cell culture. A single colony of
E. coli ECKh-432 transformed with the pZS*13 plasmid containing
both GNM_720 and GNM_721 was inoculated into 5 mL of LB medium
containing appropriate antibiotics. Similarly, single colonies of
E. coli ECKh-432 transformed with the pZS*13 plasmids containing
either GNM_720 or GNM_721 were inoculated into additional 5 mL
aliquots of LB medium containing appropriate antibiotics. Ten mL
micro-aerobic cultures were started by inoculating fresh minimal in
vivo conversion medium (see below) containing the appropriate
antibiotics with 1% of the first cultures.
[0566] Recipe of the minimal in vivo conversion medium (for 1000
mL) is as follows:
TABLE-US-00087 final concentration 1M MOPS/KOH buffer 40 mM Glucose
(40%) 1% 10XM9 salts solution 1X MgSO4 (1M) 1 mM trace minerals
(x1000) 1X 1M NaHCO3 10 mM
Microaerobic conditions were established by initially flushing
capped anaerobic bottles with nitrogen for 5 minutes, then piercing
the septum with an 18G needle following inoculation. The needle was
kept in the bottle during growth to allow a small amount of air to
enter the bottles. Protein expression was induced with 0.2 mM IPTG
when the culture reached mid-log growth phase. This is considered:
time=0 hr. The culture supernatants were analyzed for BDO, 4HB, and
other by-products as described above and in WO2008115840 (see Table
31).
TABLE-US-00088 TABLE 31 Production of BDO, 4-HB and other products
in various strains. mM Strain pZS*13S OD600 OD600 PA SA LA 4HB BDO
GBL ETOH.sub.Enz ECKh-432 720 0.420 2.221 6.36 0.00 0.10 7.71 3.03
0.07 >LLOQ ECKh-432 721 0.323 2.574 1.69 0.00 0.00 12.60 0.00
0.00 >LLOQ ECKh-432 720/721 0.378 2.469 1.70 0.00 0.01 4.23 9.16
0.24 1.52 PA = pyruvate, SA = succinate, LA = lactate, 4HB =
4-hydroxybutyrate, BDO = 1,4-butanediol, GBL = gamma-butyrolactone,
Etoh = ethanol, LLOQ = lower limit of quantification
[0567] These results demonstrate that the carboxylic acid reductase
gene, GNM_720, is required for BDO formation in ECKh-432 and its
effectiveness is increased when co-expressed with the PPTase,
GNM_721. GBL and ethanol were produced in far smaller quantities
than BDO in the strains expressing GNM_720 by itself or in
combination with GNM_721.
[0568] Additional Pathways to BDO Employing Carboxylic Acid
Reductase.
[0569] It is expected that carboxylic acid reductase can function
as a component of many pathways to 1,4-butanediol from the TCA
cycle metabolites: succinate, succinyl-CoA, and
alpha-ketoglutarate. Several of these pathways are disclosed in
FIG. 62. All routes can lead to theoretical BDO yields greater than
or equal to 1 mol/mol assuming glucose as the carbon source.
Similar high theoretical yields can be obtained from additional
substrates including sucrose, xylose, arabinose, synthesis gas,
among many others. It is expected that the expression of carboxylic
acid reductase alone or in combination with PPTase (that is, to
catalyze steps F and D of FIG. 62) is sufficient for 1,4-butanediol
production from succinate provided that sufficient endogenous
alcohol dehydrogenase activity is present to catalyze steps C and E
of FIG. 62. Candidate enzymes for steps A through Z of FIG. 62 are
described in section XXIII
Example XXII
Pathways to Putrescine that Employ Carboxylic Acid Reductase
[0570] This example describes exemplary putrescine pathways
utilizing carboxylic acid reductase.
[0571] Putrescine, also known as 1,4-diaminobutane or
butanediamine, is an organic chemical compound of the formula
NH.sub.2(CH.sub.2).sub.4NH.sub.2. It can be reacted with adipic
acid to yield the polyamide Nylon-4,6, which is marketed by DSM
(Heerlen, Netherlands) under the trade name Stanyl.TM.. Putrescine
is naturally produced, for example, by the natural breakdown of
amino acids in living and dead organisms. E. coli has been
engineered to produce putrescine by overexpressing the native
ornithine biosynthetic machinery as well as an ornithine
decarboxylase (Qian, et al., Biotechnol. Bioeng. 104(4):651-662
(2009)).
[0572] FIG. 63 describes a number of additional biosynthetic
pathways leading to the production of putrescine from succinate,
succinyl-CoA, or alpha-ketoglutarate and employing a carboxylic
acid reductase. Note that none of these pathways require formation
of an activated version of 4-aminobutyrate such as
4-aminobutyryl-CoA, which can be reduced by an acyl-CoA reductase
to 4-aminobutanal but also can readily cyclize to its lactam,
2-pyrrolidinone (Ohsugi, et al., J. Biol. Chem. 256:7642-7651
(1981)). All routes can lead to theoretical putrescine yields
greater than or equal to 1 mol/mol assuming glucose as the carbon
source. Similar high theoretical yields can be obtained from
additional substrates including sucrose, xylose, arabinose,
synthesis gas, among many others. Candidate enzymes for steps A
through U of FIG. 63 are described in Example XXIII
Example XXIII
Exemplary Enzymes for Production of C4 Compounds
[0573] This example describes exemplary enzymes for production of
C4 compounds such as 1,4-butanediol, 4-hydroxybutanal and
putrescine.
[0574] Enzyme Classes.
[0575] All transformations depicted in FIGS. 58, 62 and 63 fall
into the general categories of transformations shown in Table 32.
This example describes a number of biochemically characterized
genes in each category. Specifically listed are genes that can be
applied to catalyze the appropriate transformations in FIGS. 58, 62
and 63 when cloned and expressed. The first three digits of each
label correspond to the first three Enzyme Commission number digits
which denote the general type of transformation independent of
substrate specificity.
TABLE-US-00089 TABLE 32 Classes of Enzyme Transformations Depicted
in FIGS. 58, 62 and 63. LABEL FUNCTION 1.1.1.a Oxidoreductase (oxo
to alcohol) 1.1.1.c Oxidoreductase (2 step, acyl-CoA to alcohol)
1.2.1.b Oxidoreductase (acyl-CoA to aldehyde) 1.2.1.c
Oxidoreductase (2-oxo acid to acyl-CoA, decarboxylation) 1.2.1.d
Oxidoreductase (phosphonate reductase) 1.2.1.e Acid reductase
1.4.1.a Oxidoreductase (aminating) 2.3.1.a Acyltransferase
(transferring phosphate group to CoA) 2.6.1.a Aminotransferase
2.7.2.a Phosphotransferase (carboxy acceptor) 2.8.3.a CoA
transferase 3.1.2.a CoA hydrolase 4.1.1.a Carboxy-lyase 6.2.1.a CoA
synthetase
[0576] 1. 1. 1a Oxidoreductase (oxo to alcohol)
[0577] Aldehyde to Alcohol.
[0578] Three transformations described in FIGS. 58, 62 and 63
involve the conversion of an aldehyde to alcohol. These are
4-hydroxybutyrate dehydrogenase (step C, FIGS. 58 and 62),
1,4-butanediol dehydrogenase (step E, FIGS. 58 and 62), and
5-hydroxy-2-pentanoic acid (step Y, FIG. 62). Exemplary genes
encoding enzymes that catalyze the conversion of an aldehyde to
alcohol, that is, alcohol dehydrogenase or equivalently aldehyde
reductase, include alrA encoding a medium-chain alcohol
dehydrogenase for C2-C14 (Tani et al. Appl. Environ. Microbiol.
66:5231-5235 (2000)), ADH2 from Saccharomyces cerevisiae (Atsumi et
al. Nature 451:86-89 (2008)), yqhD from E. coli, which has
preference for molecules longer than C(3) (Sulzenbacher et al. J.
Mol. Biol. 342:489-502 (2004)), and bdh I and bdh II from C.
acetobutylicum, which converts butyryaldehyde into butanol (Walter
et al. J. Bacteriol. 174:7149-7158 (1992)). The protein sequences
for each of exemplary gene products can be found using the
following GenBank accession numbers:
TABLE-US-00090 Gene Accession No. GI No. Organism alrA BAB12273.1
9967138 Acinetobacter sp. Strain M-1 ADH2 NP_014032.1 6323961
Saccharymyces cerevisiae yqhD NP_417484.1 16130909 Escherichia coli
bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II
NP_349891.1 15896542 Clostridium acetobutylicum
[0579] Enzymes exhibiting 4-hydroxybutyrate dehydrogenase activity
(EC 1.1.1.61) also fall into this category. Such enzymes have been
characterized in Ralstonia eutropha (Bravo et al. J. Forensic Sci.
49:379-387 (2004)), Clostridium kluyveri (Wolff et al., Protein
Expr. Purif. 6:206-212 (1995)) and Arabidopsis thaliana (Breitkreuz
et al. J. Biol. Chem. 278:41552-41556 (2003)).
TABLE-US-00091 Gene Accession No. GI No. Organism 4hbd YP_726053.1
113867564 Ralstonia eutropha H16 4hbd EDK35022.1 146348486
Clostridium kluyveri DSM 555 4hbd Q94B07 75249805 Arabidopsis
thaliana
[0580] The adh1 gene from Geobacillus thermoglucosidasius M10EXG
(Jeon et al., J. Biotechnol. 135:127-133 (2008)) was shown to
exhibit high activity on both 4-hydroxybutanal and butanal (see
above). Thus this enzyme exhibits 1,4-butanediol dehydrogenase
activity.
TABLE-US-00092 Gene Accession No. GI No. Organism adh1 AAR91477.1
40795502 Geobacillus thermoglucosidasius M10EXG
[0581] Another exemplary enzyme is 3-hydroxyisobutyrate
dehydrogenase, which catalyzes the reversible oxidation of
3-hydroxyisobutyrate to methylmalonate semialdehyde. This enzyme
participates in valine, leucine and isoleucine degradation and has
been identified in bacteria, eukaryotes, and mammals. The enzyme
encoded by P84067 from Thermus thermophilus HB8 has been
structurally characterized (Lokanath et al. J. Mol. Biol.
352:905-17 (2005)). The reversibility of the human
3-hydroxyisobutyrate dehydrogenase was demonstrated using
isotopically-labeled substrate (Manning et al., Biochem. J.
231:481-484 (1985)). Additional genes encoding this enzyme include
3hidh in Homo sapiens (Hawes et al., Methods Enzymol. 324:218-228
(2000)) and Oryctolagus cuniculus (Chowdhury et al., Biosci.
Biotechnol. Biochem. 60:2043-2047 (1996); Hawes et al. Methods
Enzymol. 324:218-228 (2000)), mmsb in Pseudomonas aeruginosa, and
dhat in Pseudomonas putida (Aberhart et al., J. Chem. Soc. [Perkin
1] 6:1404-1406 (1979); Chowdhury et al., Biosci. Biotechnol
Biochem. 67:438-441 (2003); Chowdhury et al., Biosci. Biotechnol.
Biochem. 60:2043-2047 (1996)).
TABLE-US-00093 Gene Accession No. GI No. Organism P84067 P84067
75345323 Thermus thermophilus mmsb P28811.1 127211 Pseudomonas
aeruginosa dhat Q59477.1 2842618 Pseudomonas putida 3hidh P31937.2
12643395 Homo sapiens 3hidh P32185.1 416872 Oryctolagus
cuniculus
[0582] Several 3-hydroxyisobutyrate dehydrogenase enzymes have also
been shown to convert malonic semialdehyde to 3-hydroxyproprionic
acid (3-HP). Three gene candidates exhibiting this activity are
mmsB from Pseudomonas aeruginosa PAO1(62), mmsB from Pseudomonas
putida KT2440 (Liao et al., US Publication 2005/0221466) and mmsB
from Pseudomonas putida E23 (Chowdhury et al., Biosci. Biotechnol.
Biochem. 60:2043-2047 (1996)). An enzyme with 3-hydroxybutyrate
dehydrogenase activity in Alcaligenes faecalis M3A has also been
identified (Gokam et al., U.S. Pat. No. 7,393,676; Liao et al., US
Publication No. 2005/0221466). Additional gene candidates from
other organisms including Rhodobacter spaeroides can be inferred by
sequence similarity.
TABLE-US-00094 Gene Accession No. GI No. Organism mmsB AAA25892.1
151363 Pseudomonas aeruginosa mmsB NP_252259.1 15598765 Pseudomonas
aeruginosa PAO1 mmsB NP_746775.1 26991350 Pseudomonas putida KT2440
mmsB JC7926 60729613 Pseudomonas putida E23 orfB1 AAL26884 16588720
Rhodobacter spaeroides
[0583] The conversion of malonic semialdehyde to 3-HP can also be
accomplished by two other enzymes, NADH-dependent
3-hydroxypropionate dehydrogenase and NADPH-dependent malonate
semialdehyde reductase. An NADH-dependent 3-hydroxypropionate
dehydrogenase is thought to participate in beta-alanine
biosynthesis pathways from propionate in bacteria and plants
(Rathinasabapathi, J. Plant Pathol. 159:671-674 (2002); Stadtman,
J. Am. Chem. Soc. 77:5765-5766 (1955)). This enzyme has not been
associated with a gene in any organism to date. NADPH-dependent
malonate semialdehyde reductase catalyzes the reverse reaction in
autotrophic CO.sub.2-fixing bacteria. Although the enzyme activity
has been detected in Metallosphaera sedula, the identity of the
gene is not known (Alber et al. J. Bacteriol. 188:8551-8559
(2006)).
1.1.1.c Oxidoreductase (2 Step, Acyl-CoA to Alcohol).
[0584] Steps S and W of FIG. 62 depict bifunctional reductase
enzymes that can form 4-hydroxybutyrate and 1,4-butanediol,
respectively. Exemplary 2-step oxidoreductases that convert an
acyl-CoA to alcohol include those that transform substrates such as
acetyl-CoA to ethanol (for example, adhE from E. coli (Kessler et
al., FEBS. Lett. 281:59-63 (1991)) and butyryl-CoA to butanol (for
example, adhE2 from C. acetobutylicum (Fontaine et al., J.
Bacteriol. 184:821-830 (2002)). The C. acetobutylicum adhE2 gene
was shown to convert 4-hydroxybutyryl-CoA to 1,4-butanediol (see
above). In addition to reducing acetyl-CoA to ethanol, the enzyme
encoded by adhE in Leuconostoc mesenteroides has been shown to
oxidize the branched chain compound isobutyraldehyde to
isobutyryl-CoA (Kazahaya et al. J., Gen. Appl. Microbiol. 18:43-55
(1972); Koo et al., Biotechnol. Lett. 27:505-510 (2005)).
TABLE-US-00095 Gene Accession No. GI No. Organism adhE NP_415757.1
16129202 Escherichia coli adhE2 AAK09379.1 12958626 Clostridium
acetobutylicum adhE AAV66076.1 55818563 Leuconostoc
mesenteroides
[0585] Another exemplary enzyme can convert malonyl-CoA to 3-HP. An
NADPH-dependent enzyme with this activity has characterized in
Chloroflexus aurantiacus, where it participates in the
3-hydroxypropionate cycle (Hugler et al., J. Bacteriol.
184:2404-2410 (2002); Strauss and Fuchs, Eur. J. Biochem.
215:633-643 (1993)). This enzyme, with a mass of 300 kDa, is highly
substrate-specific and shows little sequence similarity to other
known oxidoreductases (Hugler et al., J. Bacteriol. 184:2404-2410
(2002)). No enzymes in other organisms have been shown to catalyze
this specific reaction; however there is bioinformatic evidence
that other organisms may have similar pathways (Klatt et al.,
Environ. Microbiol. 9:2067-2078 (2007)). Enzyme candidates in other
organisms including Roseiflexus castenholzii, Erythrobacter sp.
NAP1 and marine gamma proteobacterium HTCC2080 can be inferred by
sequence similarity.
TABLE-US-00096 Gene Accession No. GI No. Organism mcr AAS20429.1
42561982 Chloroflexus aurantiacus Rcas_2929 YP_001433009.1
156742880 Roseiflexus castenholzii NAP1_02720 ZP_01039179.1
85708113 Erythrobacter sp. NAP1 MGP2080_00535 ZP_01626393.1
119504313 marine gamma proteobacterium HTCC2080
[0586] Longer chain acyl-CoA molecules can be reduced by enzymes
such as the jojoba (Simmondsia chinensis) FAR, which encodes an
alcohol-forming fatty acyl-CoA reductase. Its overexpression in E.
coli resulted in FAR activity and the accumulation of fatty alcohol
(Metz et al., Plant Physiol. 122:635-644 2000)).
TABLE-US-00097 Gene Accession No. GI No. Organism FAR AAD38039.1
5020215 Simmondsia chinensis
1.2.1.b Oxidoreductase (Acyl-CoA to Aldehyde).
[0587] Step A of FIGS. 58, 62 and 63 involves the conversion of
succinyl-CoA to succinate semialdehyde by an aldehyde forming
succinyl-CoA reductase. Step Q of FIG. 62 depicts the conversion of
4-hydroxybutyryl-CoA to 4-hydroxybutanal by an aldehyde-forming
4-hydroxybutyryl-CoA reductase. Several acyl-CoA dehydrogenases are
capable of reducing an acyl-CoA to its corresponding aldehyde.
Exemplary genes that encode such enzymes include the Acinetobacter
calcoaceticus acr1 encoding a fatty acyl-CoA reductase (Reiser and
Somerville, J. Bacteriol. 179:2969-2975 (1997)), the Acinetobacter
sp. M-1 fatty acyl-CoA reductase (Ishige et al., Appl. Environ.
Microbiol. 68:1192-1195 (2002)), and a CoA- and NADP-dependent
succinate semialdehyde dehydrogenase encoded by the sucD gene in
Clostridium kluyveri (Sohling and Gottschalk, J. Bacteriol.
178:871-80 (1996); Sohling and Gottschalk, J. Bacteriol.
178:871-880 (1996)). SucD of P. gingivalis is another
aldehyde-forming succinyl-CoA reductase (Takahashi et al., J.
Bacteriol. 182:4704-4710 (2000)). The enzyme acylating acetaldehyde
dehydrogenase in Pseudomonas sp, encoded by bphG, is yet another as
it has been demonstrated to oxidize and acylate acetaldehyde,
propionaldehyde, butyraldehyde, isobutyraldehyde and formaldehyde
(Powlowski et al., J. Bacteriol. 175:377-385 (1993)). In addition
to reducing acetyl-CoA to ethanol, the enzyme encoded by adhE in
Leuconostoc mesenteroides has been shown to oxidize the branched
chain compound isobutyraldehyde to isobutyryl-CoA (Koo et al.,
Biotechnol. Lett. 27:505-510 (2005)). Butyraldehyde dehydrogenase
catalyzes a similar reaction, conversion of butyryl-CoA to
butyraldehyde, in solventogenic organisms such as Clostridium
saccharoperbutylacetonicum (Kosaka et al., Biosci. Biotechnol.
Biochem. 71:58-68 (2007)).
TABLE-US-00098 Gene Accession No. GI No. Organism acr1 YP_047869.1
50086359 Acinetobacter calcoaceticus acr1 AAC45217 1684886
Acinetobacter baylyi acr1 BAB85476.1 18857901 Acinetobacter sp.
Strain M-1 sucD P38947.1 730847 Clostridium kluyveri sucD
NP_904963.1 34540484 Porphyromonas gingivalis bphG BAA03892.1
425213 Pseudomonas sp adhE AAV66076.1 55818563 Leuconostoc
mesenteroides bld AAP42563.1 31075383 Clostridium
saccharoperbutylacetonicum
[0588] An additional enzyme type that converts an acyl-CoA to its
corresponding aldehyde is malonyl-CoA reductase, which transforms
malonyl-CoA to malonic semialdehyde. Malonyl-CoA reductase is a key
enzyme in autotrophic carbon fixation via the 3-hydroxypropionate
cycle in thermoacidophilic archael bacteria (Berg et al., Science
318:1782-1786 (2007); Thauer, Science 318:1732-1733 (2007)). The
enzyme utilizes NADPH as a cofactor and has been characterized in
Metallosphaera and Sulfolobus spp (Alber et al., J. Bacteriol.
188:8551-8559 (2006); Hugler et al., J. Bacteriol. 184:2404-2410
(2002)). The enzyme is encoded by Msed_0709 in Metallosphaera
sedula (Alber et al., J. Bacteriol. 188:8551-8559 (2006); Berg et
al., Science 318:1782-1786 (2007)). A gene encoding a malonyl-CoA
reductase from Sulfolobus tokodaii was cloned and heterologously
expressed in E. coli (Alber et al., J. Bacteriol. 188:8551-8559
(2006)). Although the aldehyde dehydrogenase functionality of these
enzymes is similar to the bifunctional dehydrogenase from
Chloroflexus aurantiacus, there is little sequence similarity. Both
malonyl-CoA reductase enzyme candidates have high sequence
similarity to aspartate-semialdehyde dehydrogenase, an enzyme
catalyzing the reduction and concurrent dephosphorylation of
aspartyl-4-phosphate to aspartate semialdehyde. Additional gene
candidates can be found by sequence homology to proteins in other
organisms including Sulfolobus solfataricus and Sulfolobus
acidocaldarius. Yet another candidate for CoA-acylating aldehyde
dehydrogenase is the ald gene from Clostridium beijerinckii (Toth
et al., Appl. Environ. Microbiol. 65:4973-4980 (1999)). This enzyme
has been reported to reduce acetyl-CoA and butyryl-CoA to their
corresponding aldehydes. This gene is very similar to eutE that
encodes acetaldehyde dehydrogenase of Salmonella typhimurium and E.
coli (Toth et al., Appl. Environ. Microbiol. 65:4973-4980
(1999)).
TABLE-US-00099 Gene Accession No. GI No. Organism Msed_0709
YP_001190808.1 146303492 Metallosphaera sedula mcr NP_378167.1
15922498 Sulfolobus tokodaii asd-2 NP_343563.1 15898958 Sulfolobus
solfataricus Saci_2370 YP_256941.1 70608071 Sulfolobus
acidocaldarius Ald AAT66436 49473535 Clostridium beijerinckii eutE
AAA80209 687645 Salmonella typhimurium eutE P77445 2498347
Escherichia coli
1.2.1.c Oxidoreductase (2-Oxo Acid to Acyl-CoA,
Decarboxylation).
[0589] Step AA in FIG. 62 depicts the conversion of
5-hydroxy-2-oxopentanoic acid to 4-hydroxybutyryl-CoA. Candidate
enzymes for this transformation include 1) branched-chain
2-keto-acid dehydrogenase, 2) alpha-ketoglutarate dehydrogenase,
and 3) the pyruvate dehydrogenase multienzyme complex (PDHC). These
enzymes are multi-enzyme complexes that catalyze a series of
partial reactions which result in acylating oxidative
decarboxylation of 2-keto-acids. Each of the 2-keto-acid
dehydrogenase complexes occupies key positions in intermediary
metabolism, and enzyme activity is typically tightly regulated
(Fries et al. Biochemistry 42:6996-7002 (2003)). The enzymes share
a complex but common structure composed of multiple copies of three
catalytic components: alpha-ketoacid decarboxylase (E1),
dihydrolipoamide acyltransferase (E2) and dihydrolipoamide
dehydrogenase (E3). The E3 component is shared among all
2-keto-acid dehydrogenase complexes in an organism, while the E1
and E2 components are encoded by different genes. The enzyme
components are present in numerous copies in the complex and
utilize multiple cofactors to catalyze a directed sequence of
reactions via substrate channeling. The overall size of these
dehydrogenase complexes is very large, with molecular masses
between 4 and 10 million Da (that is, larger than a ribosome).
[0590] Activity of enzymes in the 2-keto-acid dehydrogenase family
is normally low or limited under anaerobic conditions in E. coli.
Increased production of NADH (or NADPH) could lead to a
redox-imbalance, and NADH itself serves as an inhibitor to enzyme
function. Engineering efforts have increased the anaerobic activity
of the E. coli pyruvate dehydrogenase complex (Kim et al. Appl.
Environ. Microbiol. 73:1766-1771 (2007); Kim et al. J. Bacteriol.
190:3851-3858) 2008); Zhou et al. Biotechnol. Lett. 30:335-342
(2008)). For example, the inhibitory effect of NADH can be overcome
by engineering an H322Y mutation in the E3 component (Kim et al. J.
Bacteriol. 190:3851-3858 (2008)). Structural studies of individual
components and how they work together in complex provide insight
into the catalytic mechanisms and architecture of enzymes in this
family (Aevarsson et al. Nat. Struct. Biol. 6:785-792 (1999); Zhou
et al. Proc. Natl. Acad. Sci. U.S.A. 98:14802-14807 (2001)). The
substrate specificity of the dehydrogenase complexes varies in
different organisms, but generally branched-chain keto-acid
dehydrogenases have the broadest substrate range.
[0591] Alpha-ketoglutarate dehydrogenase (AKGD) converts
alpha-ketoglutarate to succinyl-CoA and is the primary site of
control of metabolic flux through the TCA cycle (Hansford, R. G.
Curr. Top. Bioenerg. 10:217-278 (1980)). Encoded by genes sucA,
sucB and lpd in E. coli, AKGD gene expression is downregulated
under anaerobic conditions and during growth on glucose (Park et
al. Mol. Microbiol. 15:473-482 (1995)). Although the substrate
range of AKGD is narrow, structural studies of the catalytic core
of the E2 component pinpoint specific residues responsible for
substrate specificity (Knapp et al. J. Mol. Biol. 280:655-668
(1998)). The Bacillus subtilis AKGD, encoded by odhAB (E1 and E2)
and pdhD (E3, shared domain), is regulated at the transcriptional
level and is dependent on the carbon source and growth phase of the
organism (Resnekov et al. Mol. Gen. Genet. 234:285-296 (1992)). In
yeast, the LPD1 gene encoding the E3 component is regulated at the
transcriptional level by glucose (Roy and Dawes J. Gen. Microbiol.
133:925-933 (1987)). The E1 component, encoded by KGD1, is also
regulated by glucose and activated by the products of HAP2 and HAP3
(Repetto and Tzagoloff Mol. Cell Biol. 9:2695-2705 (1989)). The
AKGD enzyme complex, inhibited by products NADH and succinyl-CoA,
is well-studied in mammalian systems, as impaired function of has
been linked to several neurological diseases (Tretter and dam-Vizi
Philos. Trans. R. Soc. Lond B Biol. Sci. 360:2335-2345 (2005)).
TABLE-US-00100 Gene Accession No. GI No. Organism sucA NP_415254.1
16128701 Escherichia coli str. K12 substr. MG1655 sucB NP_415255.1
16128702 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1
16128109 Escherichia coli str. K12 substr. MG1655 odhA P23129.2
51704265 Bacillus subtilis odhB P16263.1 129041 Bacillus subtilis
pdhD P21880.1 118672 Bacillus subtilis KGD1 NP_012141.1 6322066
Saccharomyces cerevisiae KGD2 NP_010432.1 6320352 Saccharomyces
cerevisiae LPD1 NP_116635.1 14318501 Saccharomyces cerevisiae
[0592] Branched-chain 2-keto-acid dehydrogenase complex (BCKAD),
also known as 2-oxoisovalerate dehydrogenase, participates in
branched-chain amino acid degradation pathways, converting 2-keto
acids derivatives of valine, leucine and isoleucine to their
acyl-CoA derivatives and CO.sub.2. The complex has been studied in
many organisms including Bacillus subtilis (Wang et al. Eur. J.
Biochem. 213:1091-1099 (1993)), Rattus norvegicus (Namba et al. J.
Biol. Chem. 244:4437-4447 (1969)) and Pseudomonas putida (Sokatch
J. Bacteriol. 148:647-652 (1981)). In Bacillus subtilis the enzyme
is encoded by genes pdhD (E3 component), bfmBB (E2 component),
bfmBAA and bfmBAB (E1 component) (Wang et al. Eur. J. Biochem.
213:1091-1099 (1993)). In mammals, the complex is regulated by
phosphorylation by specific phosphatases and protein kinases. The
complex has been studied in rat hepatocites (Chicco et al. J. Biol.
Chem. 269:19427-19434 (1994)) and is encoded by genes Bckdha (E1
alpha), Bckdhb (E1 beta), Dbt (E2), and Dld (E3). The E1 and E3
components of the Pseudomonas putida BCKAD complex have been
crystallized (Aevarsson et al. Nat. Struct. Biol. 6:785-792 (1999);
Mattevi Science 255:1544-1550 (1992)) and the enzyme complex has
been studied (Sokatch et al. J. Bacteriol. 148:647-652 (1981)).
Transcription of the P. putida BCKAD genes is activated by the gene
product of bkdR (Hester et al. Eur. J. Biochem. 233:828-836
(1995)). In some organisms including Rattus norvegicus (Paxton et
al. Biochem. J. 234:295-303 (1986)) and Saccharomyces cerevisiae
(Sinclair et al. Biochem. Mol. Biol. Int. 31:911-922 (1993)), this
complex has been shown to have a broad substrate range that
includes linear oxo-acids such as 2-oxobutanoate and
alpha-ketoglutarate, in addition to the branched-chain amino acid
precursors. The active site of the bovine BCKAD was engineered to
favor alternate substrate acetyl-CoA (Meng and Chuang, Biochemistry
33:12879-12885 (1994)).
TABLE-US-00101 Gene Accession No. GI No. Organism bfmBB NP_390283.1
16079459 Bacillus subtilis bfmBAA NP_390285.1 16079461 Bacillus
subtilis bfmBAB NP_390284.1 16079460 Bacillus subtilis pdhD
P21880.1 118672 Bacillus subtilis lpdV P09063.1 118677 Pseudomonas
putida bkdB P09062.1 129044 Pseudomonas putida bkdA1 NP_746515.1
26991090 Pseudomonas putida bkdA2 NP_746516.1 26991091 Pseudomonas
putida Bckdha NP_036914.1 77736548 Rattus norvegicus Bckdhb
NP_062140.1 158749538 Rattus norvegicus Dbt NP_445764.1 158749632
Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus
[0593] The pyruvate dehydrogenase complex, catalyzing the
conversion of pyruvate to acetyl-CoA, has also been extensively
studied. In the E. coli enzyme, specific residues in the E1
component are responsible for substrate specificity (Bisswanger, H.
J Biol Chem. 256:815-822 (1981); Bremer, J. Eur. J Biochem.
8:535-540 (1969); Gong et al. J Biol Chem. 275:13645-13653 (2000)).
As mentioned previously, enzyme engineering efforts have improved
the E. coli PDH enzyme activity under anaerobic conditions (Kim et
al. Appl. Environ. Microbiol. 73:1766-1771 (2007); Kim J.
Bacteriol. 190:3851-3858 (2008); Zhou et al. Biotechnol. Lett.
30:335-342 (2008)). In contrast to the E. coli PDH, the B. subtilis
complex is active and required for growth under anaerobic
conditions (Nakano J. Bacteriol. 179:6749-6755 (1997)). The
Klebsiella pneumoniae PDH, characterized during growth on glycerol,
is also active under anaerobic conditions (Menzel et al. J.
Biotechnol. 56:135-142 (1997)). Crystal structures of the enzyme
complex from bovine kidney (Zhou et al. Proc. Natl. Acad. Sci.
U.S.A. 98:14802-14807 (2001)) and the E2 catalytic domain from
Azotobacter vinelandii are available (Mattevi et al. Science
255:1544-1550 (1992)). Some mammalian PDH enzymes complexes can
react on alternate substrates such as 2-oxobutanoate, although
comparative kinetics of Rattus norvegicus PDH and BCKAD indicate
that BCKAD has higher activity on 2-oxobutanoate as a substrate
(Paxton et al. Biochem. J. 234:295-303 (1986)).
TABLE-US-00102 Gene Accession No. GI No. Organism aceE NP_414656.1
16128107 Escherichia coli str. K12 substr. MG1655 aceF NP_414657.1
16128108 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1
16128109 Escherichia coli str. K12 substr. MG1655 pdhA P21881.1
3123238 Bacillus subtilis pdhB P21882.1 129068 Bacillus subtilis
pdhC P21883.2 129054 Bacillus subtilis pdhD P21880.1 118672
Bacillus subtilis aceE YP_001333808.1 152968699 Klebsiella
pneumonia MGH78578 aceF YP_001333809.1 152968700 Klebsiella
pneumonia MGH78578 lpdA YP_001333810.1 152968701 Klebsiella
pneumonia MGH78578 Pdha1 NP_001004072.2 124430510 Rattus norvegicus
Pdha2 NP_446446.1 16758900 Rattus norvegicus Dlat NP_112287.1
78365255 Rattus norvegicus Dld NP_955417.1 40786469 Rattus
norvegicus
[0594] As an alternative to the large multienzyme 2-keto-acid
dehydrogenase complexes described above, some anaerobic organisms
utilize enzymes in the 2-ketoacid oxidoreductase family (OFOR) to
catalyze acylating oxidative decarboxylation of 2-keto-acids.
Unlike the dehydrogenase complexes, these enzymes contain
iron-sulfur clusters, utilize different cofactors, and use
ferredoxin or flavodixin as electron acceptors in lieu of NAD(P)H.
While most enzymes in this family are specific to pyruvate as a
substrate (POR) some 2-keto-acid:ferredoxin oxidoreductases have
been shown to accept a broad range of 2-ketoacids as substrates
including alpha-ketoglutarate and 2-oxobutanoate (Fukuda and Wakagi
Biochim. Biophys. Acta 1597:74-80 (2002); Zhang et al. J. Biochem.
120:587-599 (1996)). One such enzyme is the OFOR from the
thermoacidophilic archaeon Sulfolobus tokodaii 7, which contains an
alpha and beta subunit encoded by gene ST2300 (Fukuda and Wakagi
Biochim. Biophys. Acta 1597:74-80 (2002); Zhang et al. J. Biochem.
120:587-599 (1996)). A plasmid-based expression system has been
developed for efficiently expressing this protein in E. coli
(Fukuda et al. Eur. J. Biochem. 268:5639-5646 (2001)) and residues
involved in substrate specificity were determined (Fukuda and
Wakagi Biochim. Biophys. Acta 1597:74-80 (2002)). Two OFORs from
Aeropyrum pernix str. K1 have also been recently cloned into E.
coli, characterized, and found to react with a broad range of
2-oxoacids (Nishizawa et al. FEBS Lett. 579:2319-2322 (2005)). The
gene sequences of these OFOR candidates are available, although
they do not have GenBank identifiers assigned to date. There is
bioinformatic evidence that similar enzymes are present in all
archaea, some anaerobic bacteria and amitochondrial eukarya (Fukuda
and Wakagi Biochim. Biophys. Acta 1597:74-80 (2005)). This class of
enzyme is also interesting from an energetic standpoint, as reduced
ferredoxin could be used to generate NADH by ferredoxin-NAD
reductase (Petitdemange et al. Biochim. Biophys. Acta 421:334-337
(1976)). Also, since most of the enzymes are designed to operate
under anaerobic conditions, less enzyme engineering may be required
relative to enzymes in the 2-keto-acid dehydrogenase complex family
for activity in an anaerobic environment.
TABLE-US-00103 Gene Accession No. GI No. Organism ST2300
NP_378302.1 15922633 Sulfolobus tokodaii 7
1.2.1.d Oxidoreductase (Phosphonate Reductase).
[0595] The conversion of 4-hydroxybutyryl-phosphate to
4-hydroxybutanal can be catalyzed by an oxidoreductase in the EC
class 1.2.1. Aspartate semialdehyde dehydrogenase (ASD, EC
1.2.1.11) catalyzes the NADPH-dependent reduction of 4-aspartyl
phosphate to aspartate-4-semialdehyde. ASD participates in amino
acid biosynthesis and recently has been studied as an antimicrobial
target (Hadfield et al., Biochemistry 40:14475-14483 (2001). The E.
coli ASD structure has been solved (Hadfield et al., J. Mol. Biol.
289:991-1002 (1999)) and the enzyme has been shown to accept the
alternate substrate beta-3-methylaspartyl phosphate (Shames et al.,
J. Biol. Chem. 259:15331-15339 (1984)). The Haemophilus influenzae
enzyme has been the subject of enzyme engineering studies to alter
substrate binding affinities at the active site (Blanco et al.,
Acta Crystallogr. D. Biol. Crystallogr. 60:1388-1395 (2004); Blanco
et al., Acta Crystallogr. D. Biol. Crystallogr. 60:1808-1815
(2004)). Other ASD candidates are found in Mycobacterium
tuberculosis (Shafiani et al., J. Appl. Microbiol. 98:832-838
(2005), Methanococcus jannaschii (Faehnle et al., J. Mol. Biol.
353:1055-1068 (2005)), and the infectious microorganisms Vibrio
cholera and Heliobacter pylori (Moore et al., Protein Expr. Purif.
25:189-194 (2002)). A related enzyme candidate is
acetylglutamylphosphate reductase (EC 1.2.1.38), an enzyme that
naturally reduces acetylglutamylphosphate to
acetylglutamate-5-semialdehyde, found in S. cerevisiae (Pauwels et
al., Eur. J. Biochem. 270:1014-1024 (2003), B. subtilis (O'Reilly
and Devine, Microbiology 140 (Pt 5):1023-1025 (1994)). and other
organisms.
TABLE-US-00104 Gene Accession No. GI No. Organism asd NP_417891.1
16131307 Escherichia coli asd YP_248335.1 68249223 Haemophilus
influenzae asd AAB49996 1899206 Mycobacterium tuberculosis VC2036
NP_231670 15642038 Vibrio cholera asd YP_002301787.1 210135348
Heliobacter pylori ARG5,6 NP_010992.1 6320913 Saccharomyces
cerevisiae argC NP_389001.1 16078184 Bacillus subtilis
[0596] Other exemplary enzymes in this class include glyceraldehyde
3-phosphate dehydrogenase which converts glyceraldehyde-3-phosphate
into D-glycerate 1,3-bisphosphate (for example, E. coli gapA
(Branlant and Branlant, Eur. J. Biochem. 150:61-66 (1985)),
N-acetyl-gamma-glutamyl-phosphate reductase which converts
N-acetyl-L-glutamate-5-semialdehyde into
N-acetyl-L-glutamyl-5-phosphate (for example, E. coli argC (Parsot
et al., Gene 68:275-283 (1988)), and glutamate-5-semialdehyde
dehydrogenase, which converts L-glutamate-5-semialdehyde into
L-glutamyl-5-phosphate (for example, E. coli proA (Smith et al., J.
Bacteriol. 157:545-551 (1984)). Genes encoding
glutamate-5-semialdehyde dehydrogenase enzymes from Salmonella
typhimurium (Mahan and Csonka, J. Bacteriol. 156:1249-1262 (1983))
and Campylobacter jejuni (Louie and Chan, Mol. Gen. Genet.
240:29-35 (1993)) were cloned and expressed in E. coli.
TABLE-US-00105 Gene Accession No. GI No. Organism gapA P0A9B2.2
71159358 Escherichia coli argC NP_418393.1 16131796 Escherichia
coli proA NP_414778.1 16128229 Escherichia coli proA NP_459319.1
16763704 Salmonella typhimurium proA P53000.2 9087222 Campylobacter
jejuni
1.2.1.e Acid Reductase.
[0597] Several steps in FIGS. 58, 62 and 63 depict the conversion
of unactivated acids to aldehydes by an acid reductase. These
include the conversion of 4-hydroxybutyrate, succinate,
alpha-ketoglutarate, and 4-aminobutyrate to 4-hydroxybutanal,
succinate semialdehyde, 2,5-dioxopentanoate, and 4-aminobutanal,
respectively. One notable carboxylic acid reductase can be found in
Nocardia iowensis which catalyzes the magnesium, ATP and
NADPH-dependent reduction of carboxylic acids to their
corresponding aldehydes (Venkitasubramanian et al., J. Biol. Chem.
282:478-485 (2007)). This enzyme is encoded by the car gene and was
cloned and functionally expressed in E. coli (Venkitasubramanian et
al., J. Biol. Chem. 282:478-485 (2007)). Expression of the npt gene
product improved activity of the enzyme via post-transcriptional
modification. The npt gene encodes a specific phosphopantetheine
transferase (PPTase) that converts the inactive apo-enzyme to the
active holo-enzyme. The natural substrate of this enzyme is
vanillic acid, and the enzyme exhibits broad acceptance of aromatic
and aliphatic substrates (Venkitasubramanian et al., in
Biocatalysis in the Pharmaceutical and Biotechnology Industires,
ed. R. N. Patel, Chapter 15, pp. 425-440, CRC Press LLC, Boca
Raton, Fla. (2006)).
TABLE-US-00106 Accession Gene No. GI No. Organism car AAR91681.1
40796035 Nocardia iowensis (sp. NRRL 5646) npt ABI83656.1 114848891
Nocardia iowensis (sp. NRRL 5646)
[0598] Additional car and npt genes can be identified based on
sequence homology.
TABLE-US-00107 Gene Accession No. GI No. Organism fadD9 YP_978699.1
121638475 Mycobacterium bovis BCG BCG_2812c YP_978898.1 121638674
Mycobacterium bovis BCG nfa20150 YP_118225.1 54023983 Nocardia
farcinica IFM 10152 nfa40540 YP_120266.1 54026024 Nocardia
farcinica IFM 10152 SGR_6790 YP_001828302.1 182440583 Streptomyces
griseus subsp. griseus NBRC 13350 SGR_665 YP_001822177.1 182434458
Streptomyces griseus subsp. griseus NBRC 13350
[0599] An additional enzyme candidate found in Streptomyces griseus
is encoded by the griC and griD genes. This enzyme is believed to
convert 3-amino-4-hydroxybenzoic acid to
3-amino-4-hydroxybenzaldehyde as deletion of either griC or griD
led to accumulation of extracellular 3-acetylamino-4-hydroxybenzoic
acid, a shunt product of 3-amino-4-hydroxybenzoic acid metabolism
(Suzuki, et al., J. Antibiot. 60(6):380-387 (2007)). Co-expression
of griC and griD with SGR_665, an enzyme similar in sequence to the
Nocardia iowensis npt, can be beneficial.
TABLE-US-00108 Gene Accession No. GI No. Organism griC 182438036
YP_001825755.1 Streptomyces griseus subsp. griseus NBRC 13350 griD
182438037 YP_001825756.1 Streptomyces griseus subsp. griseus NBRC
13350 MSMEG_2956 YP_887275.1 YP_887275.1 Mycobacterium smegmatis
MC2 155 MSMEG_5739 YP_889972.1 118469671 Mycobacterium smegmatis
MC2 155 MSMEG_2648 YP_886985.1 118471293 Mycobacterium smegmatis
MC2 155 MAP1040c NP_959974.1 41407138 Mycobacterium avium subsp.
paratuberculosis K-10 MAP2899c NP_961833.1 41408997 Mycobacterium
avium subsp. paratuberculosis K-10 MMAR_2117 YP_001850422.1
183982131 Mycobacterium marinum M MMAR_2936 YP_001851230.1
183982939 Mycobacterium marinum M MMAR_1916 YP_001850220.1
183981929 Mycobacterium marinum M TpauDRAFT_33060 ZP_04027864.1
227980601 Tsukamurella paurometabola DSM 20162 TpauDRAFT_20920
ZP_04026660.1 227979396 Tsukamurella paurometabola DSM 20162
CPCC7001_1320 ZP_05045132.1 254431429 Cyanobium PCC7001
DDBDRAFT_0187729 XP_636931.1 66806417 Dictyostelium discoideum
AX4
[0600] An enzyme with similar characteristics, alpha-aminoadipate
reductase (AAR, EC 1.2.1.31), participates in lysine biosynthesis
pathways in some fungal species. This enzyme naturally reduces
alpha-aminoadipate to alpha-aminoadipate semialdehyde. The carboxyl
group is first activated through the ATP-dependent formation of an
adenylate that is then reduced by NAD(P)H to yield the aldehyde and
AMP. Like CAR, this enzyme utilizes magnesium and requires
activation by a PPTase. Enzyme candidates for AAR and its
corresponding PPTase are found in Saccharomyces cerevisiae (Morris
et al., Gene 98:141-145 (1991)), Candida albicans (Guo et al., Mol.
Genet. Genomics 269:271-279 (2003)), and Schizosaccharomyces pombe
(Ford et al., Curr. Genet. 28:131-137 (1995)). The AAR from S.
pombe exhibited significant activity when expressed in E. coli (Guo
et al., Yeast 21:1279-1288 (2004)). The AAR from Penicillium
chrysogenum accepts S-carboxymethyl-L-cysteine as an alternate
substrate, but did not react with adipate, L-glutamate or
diaminopimelate (Hijarrubia et al., J. Biol. Chem. 278:8250-8256
(2003)). The gene encoding the P. chrysogenum PPTase has not been
identified to date.
TABLE-US-00109 Gene Accession No. GI No. Organism LYS2 AAA34747.1
171867 Saccharomyces cerevisiae LYS5 P50113.1 1708896 Saccharomyces
cerevisiae LYS2 AAC02241.1 2853226 Candida albicans LYS5 AAO26020.1
28136195 Candida albicans Lys1p P40976.3 13124791
Schizosaccharomyces pombe Lys7p Q10474.1 1723561
Schizosaccharomyces pombe Lys2 CAA74300.1 3282044 Penicillium
chrysogenum
1.4.1.a Oxidoreductase (Aminating).
[0601] Glutamate dehydrogenase (Step J, FIGS. 62 and 63),
4-aminobutyrate dehydrogenase (Step M, FIGS. 62 and 63), putrescine
dehydrogenase (Step D, FIG. 63), 5-amino-2-oxopentanoate
dehydrogenase (Step P, FIG. 63), and ornithine dehydrogenase (Step
S, FIG. 63) can be catalyzed by aminating oxidoreductases. Enzymes
in this EC class catalyze the oxidative deamination of alpha-amino
acids with NAD+ or NADP+ as acceptor, and the reactions are
typically reversible. Exemplary oxidoreductases operating on amino
acids include glutamate dehydrogenase (deaminating), encoded by
gdhA, leucine dehydrogenase (deaminating), encoded by ldh, and
aspartate dehydrogenase (deaminating), encoded by nadX. The gdhA
gene product from Escherichia coli (Korber et al., J. Mol. Biol.
234:1270-1273 (1993); McPherson and Wootton, Nucleic Acids Res.
11:5257-5266 (1983)), gdh from Thermotoga maritima (Kort et al.,
Extremophiles 1:52-60 (1997); Lebbink, et al. J. Mol. Biol.
280:287-296 (1998); Lebbink et al. J. Mol. Biol. 289:357-369
(1999)), and gdhA1 from Halobacterium salinarum (Ingoldsby et al.,
Gene 349:237-244 (2005)) catalyze the reversible interconversion of
glutamate to 2-oxoglutarate and ammonia, while favoring NADP(H),
NAD(H), or both, respectively. The ldh gene of Bacillus cereus
encodes the LeuDH protein that has a wide of range of substrates
including leucine, isoleucine, valine, and 2-aminobutanoate
(Ansorge and Kula, Biotechnol. Bioeng. 68:557-562 (2000); Stoyan et
al. J. Biotechnol. 54:77-80 (1997)). The nadX gene from Thermotoga
maritime encoding for the aspartate dehydrogenase is involved in
the biosynthesis of NAD (Yang et al., J. Biol. Chem. 278:8804-8808
(2003)).
TABLE-US-00110 Gene Accession No. GI No. Organism gdhA P00370
118547 Escherichia coli gdh P96110.4 6226595 Thermotoga maritima
gdhA1 NP_279651.1 15789827 Halobacterium salinarum ldh P0A393
61222614 Bacillus cereus nadX NP_229443.1 15644391 Thermotoga
maritima
[0602] Additional glutamate dehydrogenase gene candidates are found
in Bacillus subtilis (Khan et al., Biosci. Biotechnol. Biochem.
69:1861-1870 (2005)), Nicotiana tabacum (Purnell et al., Planta
222:167-180 (2005)), Oryza sativa (Abiko et al., Plant Cell
Physiol. 46:1724-1734 (2005)), Haloferax mediterranei (Diaz et al.,
Extremophiles 10:105-115 (2006)) and Halobactreium salinarum
(Hayden et al., FEMS Microbiol. Lett. 211:37-41 (2002)). The
Nicotiana tabacum enzyme is composed of alpha and beta subunits
encoded by gdh1 and gdh2 (Purnell et al., Planta 222:167-180
(2005)). Overexpression of the NADH-dependent glutamate
dehydrogenase was found to improve ethanol production in engineered
strains of S. cerevisiae (Roca et al., Appl. Environ. Microbiol.
69:4732-4736 (2003)).
TABLE-US-00111 Gene Accession No. GI No. Organism rocG NP_391659.1
16080831 Bacillus subtilis gdh1 AAR11534.1 38146335 Nicotiana
tabacum gdh2 AAR11535.1 38146337 Nicotiana tabacum GDH Q852M0
75243660 Oryza sativa GDH Q977U6 74499858 Haloferax mediterranei
GDH P29051 118549 Halobactreium salinarum GDH2 NP_010066.1 6319986
Saccharomyces cerevisiae
[0603] An exemplary enzyme for catalyzing the conversion of
aldehydes to their corresponding primary amines is lysine
6-dehydrogenase (EC 1.4.1.18), encoded by the lysDH genes. The
lysine 6-dehydrogenase (deaminating), encoded by lysDH gene,
catalyze the oxidative deamination of the .epsilon.-amino group of
L-lysine to form 2-aminoadipate-6-semialdehyde, which in turn
nonenzymatically cyclizes to form
.DELTA.1-piperideine-6-carboxylate (Misono and Nagasaki, J.
Bacteriol. 150:398-401 (1982)). The lysDH gene from Geobacillus
stearothermophilus encodes a thermophilic NAD-dependent lysine
6-dehydrogenase (Heydari et al., Appl. Environ. Microbiol
70:937-942 (2004)). The lysDH gene from Aeropyrum pernix K1 is
identified through homology from genome projects. Additional
enzymes can be found in Agrobacterium tumefaciens (Hashimoto et
al., J. Biochem. 106:76-80 (1989); Misono and Nagasaki, J.
Bacteriol. 150:398-401 (1982)) and Achromobacter denitrificans
(Ruldeekulthamrong et al., BMB. Rep. 41:790-795 (2008)).
TABLE-US-00112 Gene Accession No. GI No. Organism lysDH BAB39707
13429872 Geobacillus stearothermophilus lysDH NP_147035.1 14602185
Aeropyrum pernix K1 lysDH NP_353966 15888285 Agrobacterium
tumefaciens lysDH AAZ94428 74026644 Achromobacter denitrificans
[0604] An enzyme that converts 3-oxoacids to 3-amino acids is
3,5-diaminohexanoate dehydrogenase (EC 1.4.1.11), an enzyme found
in organisms that ferment lysine. The gene encoding this enzyme,
kdd, was recently identified in Fusobacterium nucleatum (Kreimeyer
et al., J. Biol. Chem. 282:7191-7197 (2007)). The enzyme has been
purified and characterized in other organisms (Baker et al., J.
Biol. Chem. 247:7724-7734 (1972); Baker and van der Drift,
Biochemistry 13:292-299 (1974)), but the genes associated with
these enzymes are not known. Candidates in Myxococcus xanthus,
Porphyromonas gingivalis W83 and other sequenced organisms can be
inferred by sequence homology.
TABLE-US-00113 Gene Accession No. GI No. Organism kdd AAL93966.1
19713113 Fusobacterium nucleatum mxan_4391 ABF87267.1 108462082
Myxococcus xanthus pg_1069 AAQ66183.1 34397119 Porphyromonas
gingivalis
2.3.1.a Acyltransferase (Transferring Phosphate Group to CoA).
[0605] Step P of FIG. 62 depicts the transformation of
4-hydroxybutyryl-CoA to 4-hydroxybutyryl-Pi. Exemplary phosphate
transferring acyltransferases include phosphotransacetylase,
encoded by pta, and phosphotransbutyrylase, encoded by ptb. The pta
gene from E. coli encodes an enzyme that can convert acetyl-CoA
into acetyl-phosphate, and vice versa (Suzuki, Biochim. Biophys.
Acta 191:559-569 (1969)). This enzyme can also utilize
propionyl-CoA instead of acetyl-CoA forming propionate in the
process (Hesslinger et al., Mol. Microbiol. 27:477-492 (1998)).
Similarly, the ptb gene from C. acetobutylicum encodes an enzyme
that can convert butyryl-CoA into butyryl-phosphate (Walter et al.,
Gene 134:107-111 (1993)); Huang et al., J Mol. Microbiol.
Biotechnol. 2:33-38 (2000). Additional ptb genes can be found in
butyrate-producing bacterium L2-50 (Louis et al., J. Bacteriol.
186:2099-2106 (2004)) and Bacillus megaterium (Vazquez et al.,
Curr. Microbiol. 42:345-349 (2001)).
TABLE-US-00114 Gene Accession No. GI No. Organism pta NP_416800.1
16130232 Escherichia coli ptb NP_349676 15896327 Clostridium
acetobutylicum ptb AAR19757.1 38425288 butyrate-producing bacterium
L2-50 ptb CAC07932.1 10046659 Bacillus megaterium
2.6.1. Aminotransferase.
[0606] Aminotransferases reversibly convert an aldehyde or ketone
to an amino group. Common amino donor/acceptor combinations include
glutamate/alpha-ketoglutarate, alanine/pyruvate, and
aspartate/oxaloacetate. Several enzymes have been shown to convert
aldehydes to primary amines, and vice versa, such as
4-aminobutyrate, putrescine, and 5-amino-2-oxopentanoate. These
enzymes are particularly well suited to carry out the following
transformations: Step N in FIGS. 62 and 63, Steps E and Q in FIG.
63. Lysine-6-aminotransferase (EC 2.6.1.36) is one exemplary enzyme
capable of forming a primary amine. This enzyme function,
converting lysine to alpha-aminoadipate semialdehyde, has been
demonstrated in yeast and bacteria. Candidates from Candida utilis
(Hammer and Bode, J. Basic Microbiol. 32:21-27 (1992)),
Flavobacterium lutescens (Fujii et al., J. Biochem. 128:391-397
(2000)) and Streptomyces clavuligenus (Romero et al., J. Ind.
Microbiol. Biotechnol. 18:241-246 (1997)) have been characterized.
A recombinant lysine-6-aminotransferase from S. clavuligenus was
functionally expressed in E. coli (Tobin et al., J. Bacteriol.
173:6223-6229 (1991)). The F. lutescens enzyme is specific to
alpha-ketoglutarate as the amino acceptor (Soda and Misono,
Biochemistry 7:4110-4119 (1968)). Other enzymes which convert
aldehydes to terminal amines include the dat gene product in
Acinetobacter baumanii encoding
2,4-diaminobutanoate:2-ketoglutarate 4-transaminase (Ikai and
Yamamoto, J. Bacteriol. 179:5118-5125 (1997)). In addition to its
natural substrate, 2,4-diaminobutyrate, DAT transaminates the
terminal amines of lysine, 4-aminobutyrate and ornithine.
TABLE-US-00115 Gene Accession No. GI No. Organism lat BAB13756.1
10336502 Flavobacterium lutescens lat AAA26777.1 153343
Streptomyces clavuligenus dat P56744.1 6685373 Acinetobacter
baumanii
[0607] The conversion of an aldehyde to a terminal amine can also
be catalyzed by gamma-aminobutyrate transaminase (GABA transaminase
or 4-aminobutyrate transaminase). This enzyme naturally
interconverts succinic semialdehyde and glutamate to
4-aminobutyrate and alpha-ketoglutarate and is known to have a
broad substrate range (Liu et al., Biochemistry 43:10896-10905
2004); Schulz et al., Appl. Environ. Microbiol. 56:1-6 (1990)). The
two GABA transaminases in E. coli are encoded by gabT (Bartsch et
al., J. Bacteriol. 172:7035-7042 (1990)) and puuE (Kurihara et al.,
J. Biol. Chem. 280:4602-4608. (2005)). GABA transaminases in Mus
musculus, Pseudomonas fluorescens, and Sus scrofa have been shown
to react with a range of alternate substrates including
6-aminocaproic acid (Cooper, Methods Enzymol. 113:80-82 (1985);
Scott and Jakoby, J. Biol. Chem. 234:932-936 (1959)).
TABLE-US-00116 Gene Accession No. GI No. Organism gabT NP_417148.1
16130576 Escherichia coli puuE NP_415818.1 16129263 Escherichia
coli abat NP_766549.2 37202121 Mus musculus gabT YP_257332.1
70733692 Pseudomonas fluorescens abat NP_999428.1 47523600 Sus
scrofa
[0608] Additional enzyme candidates for interconverting aldehydes
and primary amines are putrescine transminases or other diamine
aminotransferases. The E. coli putrescine aminotransferase is
encoded by the ygjG gene, and the purified enzyme also was able to
transaminate cadaverine and spermidine (Samsonova et al., BMC
Microbiol. 3:2 (2003)). In addition, activity of this enzyme on
1,7-diaminoheptane and with amino acceptors other than
2-oxoglutarate (for example, pyruvate, 2-oxobutanoate) has been
reported (Kim, J. Biol. Chem. 239:783-786 (1964); Samsonova et al.,
BMC Microbiol. 3:2 (2003)). A putrescine aminotransferase with
higher activity with pyruvate as the amino acceptor than
alpha-ketoglutarate is the spuC gene of Pseudomonas aeruginosa (Lu
et al., J. Bacteriol. 184:3765-3773 (2002)).
TABLE-US-00117 Gene Accession No. GI No. Organism ygjG NP_417544
145698310 Escherichia coli spuC AAG03688 9946143 Pseudomonas
aeruginosa
[0609] Enzymes that transaminate 3-oxoacids include GABA
aminotransferase (described above),
beta-alanine/alpha-ketoglutarate aminotransferase and
3-amino-2-methylpropionate aminotransferase.
Beta-alanine/alpha-ketoglutarate aminotransferase (WO08027742)
reacts with beta-alanine to form malonic semialdehyde, a 3-oxoacid.
The gene product of SkPYD4 in Saccharomyces kluyveri was shown to
preferentially use beta-alanine as the amino group donor (Andersen
and Hansen, Gene 124:105-109 (1993)). SkUGA1 encodes a homologue of
Saccharomyces cerevisiae GABA aminotransferase, UGA1 (Ramos et al.,
Eur. J. Biochem. 149:401-404 (1985)), whereas SkPYD4 encodes an
enzyme involved in both beta-alanine and GABA transamination
(Andersen and Hansen, Gene 124:105-109 (1993)).
3-Amino-2-methylpropionate transaminase catalyzes the
transformation from methylmalonate semialdehyde to
3-amino-2-methylpropionate. The enzyme has been characterized in
Rattus norvegicus and Sus scrofa and is encoded by Abat (Kakimoto
et al., Biochim. Biophys. Acta 156:374-380 (1968); Tamaki et al.,
Methods Enzymol. 324:376-389 (2000)).
TABLE-US-00118 Gene Accession No. GI No. Organism SkyPYD4
ABF58893.1 98626772 Lachancea kluyveri SkUGA1 ABF58894.1 98626792
Lachancea kluyveri UGA1 NP_011533.1 6321456 Saccharomyces
cerevisiae Abat P50554.3 122065191 Rattus norvegicus Abat P80147.2
120968 Sus scrofa
[0610] Several aminotransferases transaminate the amino groups of
amino acids to form 2-oxoacids. Aspartate aminotransferase is an
enzyme that naturally transfers an oxo group from oxaloacetate to
glutamate, forming alpha-ketoglutarate and aspartate. Aspartate is
similar in structure to OHED and 2-AHD. Aspartate aminotransferase
activity is catalyzed by, for example, the gene products of aspC
from Escherichia coli (Yagi et al., FEBS Lett. 100:81-84 (1979);
Yagi et al., Methods Enzymol. 113:83-89 (1985)), AAT2 from
Saccharomyces cerevisiae (Yagi et al., J. Biochem. 92:35-43 (1982))
and ASPS from Arabidopsis thaliana (de la Torre et al., Plant J.
46:414-425 (2006); Kwok and Hanson. J. Exp. Bot. 55:595-604 (2004);
Wilkie and Warren, Protein Expr. Purif. 12:381-389 (1998)). The
enzyme from Rattus norvegicus has been shown to transaminate
alternate substrates such as 2-aminohexanedioic acid and
2,4-diaminobutyric acid (Recasens et al., Biochemistry 19:4583-4589
(1980)). Aminotransferases that work on other amino-acid substrates
can also be able to catalyze this transformation. Valine
aminotransferase catalyzes the conversion of valine and pyruvate to
2-ketoisovalerate and alanine. The E. coli gene, avtA, encodes one
such enzyme (Whalen and Berg, J. Bacteriol. 150:739-746 (1982)).
This gene product also catalyzes the transamination of
.alpha.-ketobutyrate to generate .alpha.-aminobutyrate, although
the amine donor in this reaction has not been identified (Whalen
and Berg, J. Bacteriol. 158:571-574 1984)). The gene product of the
E. coli serC catalyzes two reactions, phosphoserine
aminotransferase and phosphohydroxythreonine aminotransferase (Lam
and Winkler, J. Bacteriol. 172:6518-6528 (1990)), and activity on
non-phosphorylated substrates could not be detected (Drewke et al.,
FEBS Lett. 390:179-182 (1996)).
TABLE-US-00119 Gene Accession No. GI No. Organism aspC NP_415448.1
16128895 Escherichia coli AAT2 P23542.3 1703040 Saccharomyces
cerevisiae ASP5 P46248.2 20532373 Arabidopsis thaliana Got2 P00507
112987 Rattus norvegicus avtA YP_026231.1 49176374 Escherichia coli
serC NP_415427.1 16128874 Escherichia coli
[0611] Another enzyme candidate is alpha-aminoadipate
aminotransferase (EC 2.6.1.39), an enzyme that participates in
lysine biosynthesis and degradation in some organisms. This enzyme
interconverts 2-aminoadipate and 2-oxoadipate, using
alpha-ketoglutarate as the amino acceptor. Gene candidates are
found in Homo sapiens (Okuno et al., Enzyme Protein 47:136-148
(1993)) and Thermus thermophilus (Miyazaki et al., Microbiology
150:2327-2334 (2004)). The Thermus thermophilus enzyme, encoded by
lysN, is active with several alternate substrates including
oxaloacetate, 2-oxoisocaproate, 2-oxoisovalerate, and
2-oxo-3-methylvalerate.
TABLE-US-00120 Gene Accession No. GI No. Organism lysN BAC76939.1
31096548 Thermus thermophilus AadAT-II Q8N5Z0.2 46395904 Homo
sapiens
2.7.2.a Phosphotransferase (Carboxy Acceptor).
[0612] Phosphotransferase enzymes in the EC class 2.7.2 transform
carboxylic acids to phosphonic acids with concurrent hydrolysis of
one ATP. Step 0 of FIG. 62 involves the conversion of
4-hydroxybutyrate to 4-hydroxybutyryl-phosphate by such an enzyme.
Butyrate kinase (EC 2.7.2.7) carries out the reversible conversion
of butyryl-phosphate to butyrate during acidogenesis in C.
acetobutylicum (Cary et al., Appl. Environ. Microbiol. 56:1576-1583
(1990)). This enzyme is encoded by either of the two buk gene
products (Huang et al., J. Mol. Microbiol. Biotechnol. 2:33-38
(2000)). Other butyrate kinase enzymes are found in C. butyricum
and C. tetanomorphum (Twarog and Wolfe, J. Bacteriol. 86:112-117
(1963)). Related enzyme isobutyrate kinase from Thermotoga maritima
has also been expressed in E. coli and crystallized (Diao et al.,
Acta Crystallogr. D. Biol. Crystallogr. 59:1100-1102 (2003); Diao
and Hasson, J. Bacteriol. 191:2521-2529 (2009)). Aspartokinase
catalyzes the ATP-dependent phosphorylation of aspartate and
participates in the synthesis of several amino acids. The
aspartokinase III enzyme in E. coli, encoded by lysC, has a broad
substrate range, and the catalytic residues involved in substrate
specificity have been elucidated (Keng and Viola, Arch. Biochem.
Biophys. 335:73-81 (1996)). Two additional kinases in E. coli are
also good candidates: acetate kinase and gamma-glutamyl kinase. The
E. coli acetate kinase, encoded by ackA (Skarstedt and Silverstein,
J. Biol. Chem. 251:6775-6783 (1976)), phosphorylates propionate in
addition to acetate (Hesslinger et al., Mol. Microbiol. 27:477-492
(1998)). The E. coli gamma-glutamyl kinase, encoded by proB (Smith
et al., J. Bacteriol. 157:545-551 (1984)), phosphorylates the gamma
carbonic acid group of glutamate.
TABLE-US-00121 Gene Accession No. GI No. Organism buk1 NP_349675
15896326 Clostridium acetobutylicum buk2 Q97II1 20137415
Clostridium acetobutylicum buk2 Q9X278.1 6685256 Thermotoga
maritima lysC NP_418448.1 16131850 Escherichia coli ackA
NP_416799.1 16130231 Escherichia coli proB NP_414777.1 16128228
Escherichia coli
[0613] Acetylglutamate kinase phosphorylates acetylated glutamate
during arginine biosynthesis. This enzyme is not known to accept
alternate substrates; however, several residues of the E. coli
enzyme involved in substrate binding and phosphorylation have been
elucidated by site-directed mutagenesis (Marco-Marin et al., J.
Mol. Biol. 334:459-476 (2003); Ramon-Maiques et al., Structure
10:329-342 (2002)). The enzyme is encoded by argB in Bacillus
subtilis and E. coli (Parsot et al., Gene 68:275-283 (1988)), and
ARG5,6 in S. cerevisiae (Pauwels et al., Eur. Biochem.
270:1014-1024 (2003)). The ARG5,6 gene of S. cerevisiae encodes a
polyprotein precursor that is matured in the mitochondrial matrix
to become acetylglutamate kinase and acetylglutamylphosphate
reductase.
TABLE-US-00122 Gene Accession No. GI No. Organism argB NP_418394.3
145698337 Escherichia coli argB NP_389003.1 16078186 Bacillus
subtilis ARG5,6 NP_010992.1 6320913 Saccharomyces cerevisiae
2.8.3.a CoA Transferase.
[0614] The gene products of cat1, cat2, and cat3 of Clostridium
kluyveri have been shown to exhibit succinyl-CoA (Step G, FIGS. 62
and 63), 4-hydroxybutyryl-CoA (Step T, FIG. 62), and butyryl-CoA
acetyltransferase activity, respectively (Seedorf et al., Proc.
Natl. Acad. Sci. USA 105:2128-2133 (2008); Sohling and Gottschalk,
J. Bacteriol 178:871-880 (1996)). Similar CoA transferase
activities are also present in Trichomonas vaginalis (van Grinsven
et al., J. Biol. Chem. 283:1411-1418 (2008)) and Trypanosoma brucei
(Riviere et al., J Biol. Chem. 279:45337-45346 (2004)).
TABLE-US-00123 Gene Accession No. GI No. Organism cat1 P38946.1
729048 Clostridium kluyveri cat2 P38942.2 1705614 Clostridium
kluyveri cat3 EDK35586.1 146349050 Clostridium kluyveri TVAG_395550
XP_001330176 123975034 Trichomonas vaginalis G3 Tb11.02.0290
XP_828352 71754875 Trypanosoma brucei
[0615] An additionally useful enzyme for this type of
transformation is acyl-CoA:acetate-CoA transferase, also known as
acetate-CoA transferase (EC 2.8.3.8), which has been shown to
transfer the CoA moiety to acetate from a variety of branched and
linear acyl-CoA substrates, including isobutyrate (Matthies and
Schink, Appl. Environ. Microbiol. 58:1435-1439 (1992)), valerate
(Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908
(1968)) and butanoate (Vanderwinkel, supra (1968)). This enzyme is
encoded by atoA (alpha subunit) and atoD (beta subunit) in E. coli
sp. K12 (Korolev et al., Acta Crystallogr. D Biol. Crystallo.
58:2116-2121 (2002); Vanderwinkel, supra (1968)). Similar enzymes
exist in Corynebacterium glutamicum ATCC 13032 (Duncan et al.,
Appl. Environ. Microbiol. 68:5186-5190 (2002)), Clostridium
acetobutylicum (Cary et al., Appl. Environ. Microbiol. 56:1576-1583
(1990); Wiesenborn et al., Appl. Environ. Microbiol. 55:323-329
(1989)), and Clostridium saccharoperbutylacetonicum (Kosaka et al.,
Biosci. Biotechnol. Biochem. 71:58-68 (2007)).
TABLE-US-00124 Gene Accession No. GI No. Organism atoA P76459.1
2492994 Escherichia coli K12 atoD P76458.1 2492990 Escherichia coli
K12 actA YP_226809.1 62391407 Corynebacterium glutamicum cg0592
YP_224801.1 62389399 Corynebacterium glutamicum ctfA NP_149326.1
15004866 Clostridium acetobutylicum ctfB NP_149327.1 15004867
Clostridium acetobutylicum ctfA AAP42564.1 31075384 Clostridium
saccharoperbutyl- acetonicum ctfB AAP42565.1 31075385 Clostridium
saccharoperbutyl- acetonicum
[0616] The glutaconate-CoA-transferase (EC 2.8.3.12) enzyme from
anaerobic bacterium Acidaminococcus fermentans reacts with diacid
glutaconyl-CoA and 3-butenoyl-CoA (Mack and Buckel, FEBS Lett.
405:209-212 (1997)). The genes encoding this enzyme are gctA and
gctB. This enzyme has reduced but detectable activity with other
CoA derivatives including glutaryl-CoA, 2-hydroxyglutaryl-CoA,
adipyl-CoA and acrylyl-CoA (Buckel et al., Eur. J. Biochem.
118:315-321 (1981)). The enzyme has been cloned and expressed in E.
coli (Mac et al., Eur. J. Biochem. 226:41-51 (1994)).
TABLE-US-00125 Gene Accession No. GI No. Organism gctA CAA57199.1
559392 Acidaminococcus fermentans gctB CAA57200.1 559393
Acidaminococcus fermentans
3.1.2.a CoA Hydrolase.
[0617] Enzymes in the 3.1.2 family hydrolyze acyl-CoA molecules to
their corresponding acids. However, such enzymes can be modified to
empart CoA-ligase or synthetase functionality if coupled to an
energy source such as a proton pump or direct ATP hydrolysis.
Several eukaryotic acetyl-CoA hydrolases (EC 3.1.2.1) have broad
substrate specificity. For example, the enzyme from Rattus
norvegicus brain (Robinson et al., Biochem. Biophys. Res. Commun.
71:959-965 (1976)) can react with butyryl-CoA, hexanoyl-CoA and
malonyl-CoA. Though its sequence has not been reported, the enzyme
from the mitochondrion of the pea leaf also has a broad substrate
specificity, with demonstrated activity on acetyl-CoA,
propionyl-CoA, butyryl-CoA, palmitoyl-CoA, oleoyl-CoA,
succinyl-CoA, and crotonyl-CoA (Zeiher and Randall, Plant. Physiol.
94:20-27 (1990)). The acetyl-CoA hydrolase, ACH1, from S.
cerevisiae represents another candidate hydrolase (Buu et al., J.
Biol. Chem. 278:17203-17209 (2003)).
TABLE-US-00126 Gene Accession No. GI No. Organism acot12
NP_570103.1 18543355 Rattus norvegicus ACH1 NP_009538 6319456
Saccharomyces cerevisiae
[0618] Another candidate hydrolase is the human dicarboxylic acid
thioesterase, acot8, which exhibits activity on glutaryl-CoA,
adipyl-CoA, suberyl-CoA, sebacyl-CoA, and dodecanedioyl-CoA (Westin
et al., J. Biol. Chem. 280:38125-38132 (2005)) and the closest E.
coli homolog, tesB, which can also hydrolyze a broad range of CoA
thioesters (Naggert et al., J. Biol. Chem. 266:11044-11050 (1991)).
A similar enzyme has also been characterized in the rat liver
(Deana, Biochem. Int. 26:767-773 (1992)). Other potential E. coli
thioester hydrolases include the gene products of tesA (Bonner and
Bloch, J. Biol. Chem. 247:3123-3133 (1972)), ybgC (Kuznetsova et
al., FEMS Microbiol. Rev. 29:263-279 (2005); Zhuang et al., FEBS
Lett. 516:161-163 (2002)), paaI (Song et al., J. Biol. Chem.
281:11028-11038 (2006)), and ybdB (Leduc et al., J. Bacteriol.
189:7112-7126 (2007)).
TABLE-US-00127 Gene Accession No. GI No. Organism acot8 CAA15502
3191970 Homo sapiens tesB NP_414986 16128437 Escherichia coli acot8
NP_570112 51036669 Rattus norvegicus tesA NP_415027 16128478
Escherichia coli ybgC NP_415264 16128711 Escherichia coli paaI
NP_415914 16129357 Escherichia coli ybdB NP_415129 16128580
Escherichia coli
[0619] Yet another candidate hydrolase is the glutaconate
CoA-transferase from Acidaminococcus fermentans. This enzyme was
transformed by site-directed mutagenesis into an acyl-CoA hydrolase
with activity on glutaryl-CoA, acetyl-CoA and 3-butenoyl-CoA (Mack
and Buckel, FEBS Lett. 405:209-212 (1997)). This indicates that the
enzymes encoding succinyl-CoA:3-ketoacid-CoA transferases and
acetoacetyl-CoA:acetyl-CoA transferases can also serve as
candidates for this reaction step but would likely require certain
mutations to change their function.
TABLE-US-00128 Gene Accession No. GI No. Organism gctA CAA57199.1
559392 Acidaminococcus fermentans gctB CAA57200.1 559393
Acidaminococcus fermentans
[0620] Additional hydrolase enzymes include 3-hydroxyisobutyryl-CoA
hydrolase which has been described to efficiently catalyze the
conversion of 3-hydroxyisobutyryl-CoA to 3-hydroxyisobutyrate
during valine degradation (Shimomura et al., J. Biol. Chem.
269:14248-14253 (1994)). Genes encoding this enzyme include hibch
of Rattus norvegicus (Shimomura et al., supra (1994); Shimomura et
al., Methods Enzymol. 324:229-240 (2000)) and Homo sapiens
(Shimomura et al., supra (1994). Candidate genes by sequence
homology include hibch of Saccharomyces cerevisiae and BC_2292 of
Bacillus cereus.
TABLE-US-00129 Gene Accession No. GI No. Organism hibch Q5XIE6.2
146324906 Rattus norvegicus hibch Q6NVY1.2 146324905 Homo sapiens
hibch P28817.2 2506374 Saccharomyces cerevisiae BC_2292 AP09256
29895975 Bacillus cereus
4.1.1.a Carboxy-Lyase.
[0621] Decarboxylation of Alpha-Keto Acids.
[0622] Alpha-ketoglutarate decarboxylase (Step B, FIGS. 58, 62 and
63), 5-hydroxy-2-oxopentanoic acid decarboxylase (Step Z, FIG. 62),
and 5-amino-2-oxopentanoate decarboxylase (Step R, FIG. 63) all
involve the decarboxylation of an alpha-ketoacid. The
decarboxylation of keto-acids is catalyzed by a variety of enzymes
with varied substrate specificities, including pyruvate
decarboxylase (EC 4.1.1.1), benzoylformate decarboxylase (EC
4.1.1.7), alpha-ketoglutarate decarboxylase and branched-chain
alpha-ketoacid decarboxylase.
[0623] Pyruvate decarboxylase (PDC), also termed keto-acid
decarboxylase, is a key enzyme in alcoholic fermentation,
catalyzing the decarboxylation of pyruvate to acetaldehyde. The
enzyme from Saccharomyces cerevisiae has a broad substrate range
for aliphatic 2-keto acids including 2-ketobutyrate,
2-ketovalerate, 3-hydroxypyruvate and 2-phenylpyruvate (Davie et
al., J. Biol. Chem. 267:16601-16606 (1992)). This enzyme has been
extensively studied, engineered for altered activity, and
functionally expressed in E. coli (Killenberg-Jabs et al., Eur. J.
Biochem. 268:1698-1704 (2001); Li and Jordan, Biochemistry
38:10004-10012 (1999); ter Schure et al., Appl. Environ. Microbiol.
64:1303-1307 (1998)). The PDC from Zymomonas mobilus, encoded by
pdc, also has a broad substrate range and has been a subject of
directed engineering studies to alter the affinity for different
substrates (Siegert et al., Protein Eng. Des. Sel. 18:345-357
(2005)). The crystal structure of this enzyme is available
(Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001)).
Other well-characterized PDC candidates include the enzymes from
Acetobacter pasteurians (Chandra et al., Arch. Microbiol.
176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al., Eur.
J. Biochem. 269:3256-3263 (2002)).
TABLE-US-00130 Gene Accession No. GI No. Organism pdc P06672.1
118391 Zymomonas mobilus pdc1 P06169 30923172 Saccharomyces
cerevisiae pdc AM21208 20385191 Acetobacter pasteurians pdc1 Q12629
52788279 Kluyveromyces lactis
[0624] Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a
broad substrate range and has been the target of enzyme engineering
studies. The enzyme from Pseudomonas putida has been extensively
studied and crystal structures of this enzyme are available (Hasson
et al., Biochemistry 37:9918-9930 (1998); Polovnikova et al.,
Biochemistry 42:1820-1830 (2003). Site-directed mutagenesis of two
residues in the active site of the Pseudomonas putida enzyme
altered the affinity (Km) of naturally and non-naturally occurring
substrates (Siegert et al., Protein Eng. Des. Sel. 18:345-357
(2005)). The properties of this enzyme have been further modified
by directed engineering (Lingen et al., Protein Eng. 15:585-593
(2002); Lingen et al., Chembiochem. 4:721-726 (2003)). The enzyme
from Pseudomonas aeruginosa, encoded by mdlC, has also been
characterized experimentally (Barrowman et al., FEMS Microbiol.
Lett. 34:57-60 (1986)). Additional gene candidates from Pseudomonas
stutzeri, Pseudomonas fluorescens and other organisms can be
inferred by sequence homology or identified using a growth
selection system developed in Pseudomonas putida (Henning et al.,
Appl. Environ. Microbiol. 72:7510-7517 (2006)).
TABLE-US-00131 Gene Accession No. GI No. Organism mdlC P20906.2
3915757 Pseudomonas putida mdlC Q9HUR2.1 81539678 Pseudomonas
aeruginosa dpgB ABN80423.1 126202187 Pseudomonas stutzeri ilvB-1
YP_260581.1 70730840 Pseudomonas fluorescens
[0625] A third enzyme capable of decarboxylating 2-oxoacids is
alpha-ketoglutarate decarboxylase (KGD). The substrate range of
this class of enzymes has not been studied to date. The KDC from
Mycobacterium tuberculosis (Tian et al., Proc. Natl. Acad. Sci. USA
102:10670-10675 (2005)) has been cloned and functionally expressed.
However, it is not an ideal candidate for strain engineering
because it is large (.about.130 kD) and GC-rich. KDC enzyme
activity has been detected in several species of rhizobia including
Bradyrhizobium japonicum and Mesorhizobium loti (Green et al., J.
Bacteriol. 182:2838-2844 (2000). Although the KDC-encoding gene(s)
have not been isolated in these organisms, the genome sequences are
available, and several genes in each genome are annotated as
putative KDCs. A KDC from Euglena gracilis has also been
characterized, but the gene associated with this activity has not
been identified to date (Shigeoka and Nakano, Arch. Biochem.
Biophys. 288:22-28 (1991)). The first twenty amino acids starting
from the N-terminus were sequenced (MTYKAPVKDVKFLLDKVFKV; SEQ ID
NO:45) (Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22-28
(1991)). The gene can be identified by testing candidate genes
containing this N-terminal sequence for KDC activity.
TABLE-US-00132 Gene Accession No. GI No. Organism kgd O50463.4
160395583 Mycobacterium tuberculosis kgd NP_767092.1 27375563
Bradyrhizobium japonicum kgd NP_105204.1 13473636 Mesorhizobium
loti
[0626] A fourth candidate enzyme for catalyzing this reaction is
branched chain alpha-ketoacid decarboxylase (BCKA). This class of
enzyme has been shown to act on a variety of compounds varying in
chain length from 3 to 6 carbons (Oku and Kaneda, J. Biol. Chem.
263:18386-18396 (1988); Smit et al., B. A., J. E. Hylckama Vlieg,
W. J. Engels, L. Meijer, J. T. Wouters, and G. Smit.
Identification, cloning, and characterization of a Lactococcus
lactis branched-chain alpha-keto acid decarboxylase involved in
flavor formation. Appl. Environ. Microbiol. 71:303-311 (2005)). The
enzyme in Lactococcus lactis has been characterized on a variety of
branched and linear substrates including 2-oxobutanoate,
2-oxohexanoate, 2-oxopentanoate, 3-methyl-2-oxobutanoate,
4-methyl-2-oxobutanoate and isocaproate (Smit et al., Appl.
Environ. Microbiol. 71:303-311 (2005)). The enzyme has been
structurally characterized (Berg et al., Science 318:1782-1786
(2007)). Sequence alignments between the Lactococcus lactis enzyme
and the pyruvate decarboxylase of Zymomonas mobilus indicate that
the catalytic and substrate recognition residues are nearly
identical (Siegert et al., Protein Eng. Des. Sel. 18:345-357
(2005)), so this enzyme would be a promising candidate for directed
engineering. Decarboxylation of alpha-ketoglutarate by a BCKA was
detected in Bacillus subtilis; however, this activity was low (5%)
relative to activity on other branched-chain substrates (Oku and
Kaneda. Biosynthesis of branched-chain fatty acids in Bacillus
subtilis. A decarboxylase is essential for branched-chain fatty
acid synthetase. J. Biol. Chem. 263:18386-18396 (1988)), and the
gene encoding this enzyme has not been identified to date.
Additional BCKA gene candidates can be identified by homology to
the Lactococcus lactis protein sequence. Many of the high-scoring
BLASTp hits to this enzyme are annotated as indolepyruvate
decarboxylases (EC 4.1.1.74). Indolepyruvate decarboxylase (IPDA)
is an enzyme that catalyzes the decarboxylation of indolepyruvate
to indoleacetaldehyde in plants and plant bacteria.
TABLE-US-00133 Gene Accession No. GI No. Organism kdcA AAS49166.1
44921617 Lactococcus lactis
[0627] Recombinant branched chain alpha-keto acid decarboxylase
enzymes derived from the E1 subunits of the mitochondrial
branched-chain keto acid dehydrogenase complex from Homo sapiens
and Bos taurus have been cloned and functionally expressed in E.
coli (Davie et al., J. Biol. Chem. 267:16601-16606 1992); Wynn et
al., J. Biol. Chem. 267:1881-1887 (1992); Wynn et al., J. Biol.
Chem. 267:12400-12403 (1992)). In these studies, the authors found
that co-expression of chaperonins GroEL and GroES enhanced the
specific activity of the decarboxylase by 500-fold (Wynn et al., J.
Biol. Chem. 267:12400-12403 (1992)). These enzymes are composed of
two alpha and two beta subunits.
TABLE-US-00134 Gene Accession No. GI No. Organism BCKDHB
NP_898871.1 34101272 Homo sapiens BCKDHA NP_000700.1 11386135 Homo
sapiens BCKDHB P21839 115502434 Bos taurus BCKDHA P11178 129030 Bos
taurus
[0628] Decarboxylation of Alpha-Keto Acids.
[0629] Several ornithine decarboxylase (Step U, FIG. 63) enzymes
also exhibit activity on lysine and other similar compounds. Such
enzymes are found in Nicotiana glutinosa (Lee and Cho, Biochem. J.
360:657-665 (2001)), Lactobacillus sp. 30a (Guirard and Snell, J.
Biol. Chem. 255:5960-5964 (1980)) and Vibrio vulnificus (Lee et
al., J. Biol. Chem. 282:27115-27125 (2007)). The enzymes from
Lactobacillus sp. 30a (Momany et al., J. Mol. Biol. 252:643-655
(1995)) and V. vulnificus have been crystallized. The V. vulnificus
enzyme efficiently catalyzes lysine decarboxylation, and the
residues involved in substrate specificity have been elucidated
(Lee et al., J. Biol. Chem. 282:27115-27125 (2007)). A similar
enzyme has been characterized in Trichomonas vaginalis, but the
gene encoding this enzyme is not known (Yarlett et al., Biochem. J.
293 (Pt 2):487-493 (1993)).
TABLE-US-00135 Gene Accession No. GI No. Organism AF323910.1:1 . .
. 1299 AAG45222.1 12007488 Nicotiana glutinosa odc1 P43099.2
1169251 Lactobacillus sp. 30a VV2_1235 NP_763142.1 27367615 Vibrio
vulnificus
[0630] Glutamate decarboxylase enzymes (Step L, FIGS. 62 and 63)
are also well-characterized. Exemplary glutamate decarboxylases can
be found in E. coli (De Biase et al., Protein Expr. Purif.
8:430-438 (1996)), S. cerevisiae (Coleman et al., J. Biol. Chem.
276:244-250 (2001)), and Homo sapiens (Bu et al., Proc. Natl. Acad.
Sci. USA 89:2115-2119 (1992); Bu and Tobin, Genomics 21:222-228
(1994)).
TABLE-US-00136 Gene Accession No. GI No. Organism GAD1 NP_000808
58331246 Homo sapiens GAD2 NP_001127838 197276620 Homo sapiens gadA
NP_417974 16131389 Escherichia coli gadB NP_416010 16129452
Escherichia coli GAD1 NP_013976 6323905 Saccharomyces
cerevisiae
[0631] Lysine decarboxylase (EC 4.1.1.18) catalyzes the
decarboxylation of lysine to cadaverine. Two isozymes of this
enzyme are encoded in the E. coli genome by genes cadA and ldcC.
CadA is involved in acid resistance and is subject to positive
regulation by the cadC gene product (Lemonnier and Lane,
Microbiology 144 (Pt 3):751-760 (1998)). CadC accepts hydroxylysine
and S-aminoethylcysteine as alternate substrates, and
2-Aminopimelate and 6-ACA act as competitive inhibitors to this
enzyme (Sabo et al., Biochemistry 13:662-670 (1974)). Directed
evolution or other enzyme engineering methods can be utilized to
increase the activity for this enzyme to decarboxylate
2-aminopimelate. The constitutively expressed ldc gene product is
less active than CadA (Lemonnier and Lane, Microbiology 144 (Pt
3):751-760 (1998)). A lysine decarboxylase analogous to CadA was
recently identified in Vibrio parahaemolyticus (Tanaka et al., J.
Appl. Microbiol. 104:1283-1293 (2008)). The lysine decarboxylase
from Selenomonas ruminantium, encoded by ldc, bears sequence
similarity to eukaryotic ornithine decarboxylases, and accepts both
L-lysine and L-ornithine as substrates (Takatsuka et al., Biosci.
Biotechnol. Biochem. 63:1843-1846 (1999)). Active site residues
were identified and engineered to alter the substrate specificity
of the enzyme (Takatsuka et al., J. Bacteriol. 182:6732-6741
(2000)).
TABLE-US-00137 Gene Accession No. GI No. Organism cadA AAA23536.1
145458 Escherichia coli ldcC AAC73297.1 1786384 Escherichia coli
ldc O50657.1 13124043 Selenomonas ruminantium cadA AB124819.1
44886078 Vibrio parahaemolyticus
6.2.1.a CoA Synthetase.
[0632] CoA synthetase or ligase reactions are required by Step I of
FIGS. 62 and 63, and Step V of FIG. 62. Succinate or
4-hydroxybutyrate are the required substrates. Exemplary genes
encoding enzymes likely to carry out these transformations include
the sucCD genes of E. coli, which naturally form a succinyl-CoA
synthetase complex. This enzyme complex naturally catalyzes the
formation of succinyl-CoA from succinate with the concomitant
consumption of one ATP, a reaction which is reversible in vivo
(Buck et al., Biochem. 24:6245-6252 (1985)).
TABLE-US-00138 Gene Accession No. GI No. Organism sucC NP_415256.1
16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia
coli
[0633] Additional exemplary CoA-ligases include the rat
dicarboxylate-CoA ligase for which the sequence is yet
uncharacterized (Vamecq et al., Biochemical J. 230:683-693 (1985)),
either of the two characterized phenylacetate-CoA ligases from P.
chrysogenum (Lamas-Maceiras et al., Biochem. J. 395:147-155 (2005);
Wang et al., Biochem Biophy Res Commun 360(2):453-458 (2007)), the
phenylacetate-CoA ligase from Pseudomonas putida (Martinez-Blanco
et al., J. Biol. Chem. 265:7084-7090 (1990)), and the
6-carboxyhexanoate-CoA ligase from Bacillus subtilis (Bower et al.,
J. Bacteriol. 178(14):4122-4130 (1996)). Additional candidate
enzymes are acetoacetyl-CoA synthetases from Mus musculus (Hasegawa
et al., Biochim. Biophys. Acta 1779:414-419 (2008)) and Homo
sapiens (Ohgami et al., Biochem. Pharmacol. 65:989-994 (2003)),
which naturally catalyze the ATP-dependant conversion of
acetoacetate into acetoacetyl-CoA. 4-Hydroxybutyryl-CoA synthetase
activity has been demonstrated in Metallosphaera sedula (Berg et
al., Science 318:1782-1786 (2007)). This function has been
tentatively assigned to the Msed_1422 gene.
TABLE-US-00139 Gene Accession No. GI No. Organism phl CAJ15517.1
77019264 Penicillium chrysogenum phlB ABS19624.1 152002983
Penicillium chrysogenum paaF AAC24333.2 22711873 Pseudomonas putida
bioW NP_390902.2 50812281 Bacillus subtilis AACS NP_084486.1
21313520 Mus musculus AACS NP_076417.2 31982927 Homo sapiens
Msed_1422 YP_001191504 146304188 Metallosphaera sedula
[0634] ADP-forming acetyl-CoA synthetase (ACD, EC 6.2.1.13) is
another candidate enzyme that couples the conversion of acyl-CoA
esters to their corresponding acids with the concurrent synthesis
of ATP. Several enzymes with broad substrate specificities have
been described in the literature. ACD I from Archaeoglobus
fulgidus, encoded by AF1211, was shown to operate on a variety of
linear and branched-chain substrates including acetyl-CoA,
propionyl-CoA, butyryl-CoA, acetate, propionate, butyrate,
isobutyryate, isovalerate, succinate, fumarate, phenylacetate,
indoleacetate (Musfeldt et al., J. Bacteriol. 184:636-644 (2002)).
The enzyme from Haloarcula marismortui (annotated as a succinyl-CoA
synthetase) accepts propionate, butyrate, and branched-chain acids
(isovalerate and isobutyrate) as substrates, and was shown to
operate in the forward and reverse directions (Brasen et al., Arch.
Microbiol. 182:277-287 (2004)). The ACD encoded by PAE3250 from
hyperthermophilic crenarchaeon Pyrobaculum aerophilum showed the
broadest substrate range of all characterized ACDs, reacting with
acetyl-CoA, isobutyryl-CoA (preferred substrate) and
phenylacetyl-CoA (Brasen et al., supra (2004)). The enzymes from A.
fulgidus, H. marismortui and P. aerophilum have all been cloned,
functionally expressed, and characterized in E. coli (Musfeldt et
al., supra; Brasen et al., supra (2004)).
TABLE-US-00140 Gene Accession No. GI No. Organism AF1211
NP_070039.1 11498810 Archaeoglobus fulgidus DSM 4304 scs
YP_135572.1 55377722 Haloarcula marismortui ATCC 43049 PAE3250
NP_560604.1 18313937 Pyrobaculum aerophilum str. IM2
[0635] Throughout this application various publications have been
referenced. The disclosures of these publications in their
entireties, including GenBank and GI number publications, are
hereby incorporated by reference in this application in order to
more fully describe the state of the art to which this invention
pertains. Although the invention has been described with reference
to the examples provided above, it should be understood that
various modifications can be made without departing from the spirit
of the invention.
Sequence CWU 1
1
93159DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 1gacgaattcg ctagcaagag gagaagtcga catgtccaat
tcactggccg tcgttttac 59247DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 2gaccctagga agctttctag
agtcgaccta tgcggcatca gagcaga 47318DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
3atgtaccgca agttccgc 18418DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 4caatttgccg atgcccag
18520DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 5gctgaccact gaagactttg 20619DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
6gatcagggct tcggtgtag 19727DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 7ttggtgcggg ccaagcagga tctgctc
27830DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 8tcagccgaac gcctcgtcga ggatctcctg
30932DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 9tggccaacat aagttcacca ttcgggcaaa ac
321029DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 10tctcttcaac cagccattcg ttttgcccg
291127DNAClostridium acetobutylicum 11attaaagtta agtggaggaa tgttaac
271222DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 12acacgcggat ccaacgtccc gg 221323DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
13agcggctccg ctagccgctt atg 231424DNAArtificial SequenceDescription
of Artificial Sequence Synthetic primer 14aagccgttgc tgcagctctt
gagc 241523DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 15atctccggcg gtcggatccg tcg 231620DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
16aaagcggcta gccacgccgc 201720DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 17attacacgag gtacccaacg
201822DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 18atgctggcgt acaaaggtgt cc 221922DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
19ggacaccttt gtacgccagc at 222025DNAArtificial SequenceDescription
of Artificial Sequence Synthetic primer 20atcgcctaca ctaaaccaga
agtgg 252125DNAArtificial SequenceDescription of Artificial
Sequence Synthetic primer 21ccacttctgg tttagtgtag gcgat
252220DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 22aggcagttcc ataggatggc 202355DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
23tgacatgtaa cacctacctt ctgtgcctgt gccagtggtt gctgtgatat agaag
552448DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 24ataataatac atatgaacca tgcgagttac gggcctataa
gccaggcg 482542DNAArtificial SequenceDescription of Artificial
Sequence Synthetic primer 25agtttttcga tatctgcatc agacaccggc
acattgaaac gg 422660DNAArtificial SequenceDescription of Artificial
Sequence Synthetic primer 26ctggcacagg cacagaaggt aggtgttaca
tgtcagaacg tttacacaat gacgtggatc 602749DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
27agacaaatcg gttgccgttt gttaagccag gcgagatatg atctatatc
492854DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 28gagttttgat ttcagtactc atcatgtaac acctaccttc
ttgctgtgat atag 542954DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 29ctatatcaca gcaagaaggt
aggtgttaca tgatgagtac tgaaatcaaa actc 543049DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
30gatatagatc atatctcgcc tggcttaaca aacggcaacc gatttgtct
493170DNAArtificial SequenceDescription of Artificial Sequence
Synthetic oligonucleotide 31tattgtgcat acagatgaat ttttatgcaa
acagtcagcc ctgaagaagg gtgtaggctg 60gagctgcttc 703270DNAArtificial
SequenceDescription of Artificial Sequence Synthetic
oligonucleotide 32caaaaaaccg gagtctgtgc tccggttttt tattatccgc
taatcaatta catatgaata 60tcctccttag 703351DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
33ataataatag aattcgtttg ctacctaaat tgccaactaa atcgaaacag g
513447DNAArtificial SequenceDescription of Artificial Sequence
Synthetic primer 34tattattatg gtaccaatat catgcagcaa acggtgcaac
attgccg 473547DNAArtificial SequenceDescription of Artificial
Sequence Synthetic primer 35tgatctggaa gaattcatcg gctttaccac
cgtcaaaaaa aacggcg 473648DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 36ataaaaccct gcagcggaaa
cgaagtttta tccatttttg gttacctg 483735DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
37ggaagagagg ctggtaccca gaagccacag cagga 353838DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
38gtaatcactg cgtaagcgcc atgccccggc gttaattc 383925DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
39attgccgcgt tcctcctgct gtcga 254024DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
40cgacagcagg aggaacgcgg caat 244175DNAArtificial
SequenceDescription of Artificial Sequence Synthetic primer
41gtttgcacgc tatagctgag gttgttgtct tccagcaacg taccgtatac aataggcgta
60tcacgaggcc ctttc 754270DNAArtificial SequenceDescription of
Artificial Sequence Synthetic primer 42gctacagcat gtcacacgat
ctcaacggtc ggatgaccaa tctggctggt atgggaatta 60gccatggtcc
704373DNAArtificial SequenceDescription of Artificial Sequence
Synthetic oligonucleotide 43tgtgagtgaa agtcacctgc cttaatatct
caaaactcat cttcgggtga cgaaatatgg 60cgtgactcga tac
734470DNAArtificial SequenceDescription of Artificial Sequence
Synthetic oligonucleotide 44tctgtatcag gctgaaaatc ttctctcatc
cgccaaaaca gcttcggcgt taagatgcgc 60gctcaaggac 704520PRTEuglena
gracilis 45Met Thr Tyr Lys Ala Pro Val Lys Asp Val Lys Phe Leu Leu
Asp Lys 1 5 10 15 Val Phe Lys Val 20 462036DNAEscherichia coli
46atgaacttac atgaatatca ggcaaaacaa ctttttgccc gctatggctt accagcaccg
60gtgggttatg cctgtactac tccgcgcgaa gcagaagaag ccgcttcaaa aatcggtgcc
120ggtccgtggg tagtgaaatg tcaggttcac gctggtggcc gcggtaaagc
gggcggtgtg 180aaagttgtaa acagcaaaga agacatccgt gcttttgcag
aaaactggct gggcaagcgt 240ctggtaacgt atcaaacaga tgccaatggc
caaccggtta accagattct ggttgaagca 300gcgaccgata tcgctaaaga
gctgtatctc ggtgccgttg ttgaccgtag ttcccgtcgt 360gtggtcttta
tggcctccac cgaaggcggc gtggaaatcg aaaaagtggc ggaagaaact
420ccgcacctga tccataaagt tgcgcttgat ccgctgactg gcccgatgcc
gtatcaggga 480cgcgagctgg cgttcaaact gggtctggaa ggtaaactgg
ttcagcagtt caccaaaatc 540ttcatgggcc tggcgaccat tttcctggag
cgcgacctgg cgttgatcga aatcaacccg 600ctggtcatca ccaaacaggg
cgatctgatt tgcctcgacg gcaaactggg cgctgacggc 660aacgcactgt
tccgccagcc tgatctgcgc gaaatgcgtg accagtcgca ggaagatccg
720cgtgaagcac aggctgcaca gtgggaactg aactacgttg cgctggacgg
taacatcggt 780tgtatggtta acggcgcagg tctggcgatg ggtacgatgg
acatcgttaa actgcacggc 840ggcgaaccgg ctaacttcct tgacgttggc
ggcggcgcaa ccaaagaacg tgtaaccgaa 900gcgttcaaaa tcatcctctc
tgacgacaaa gtgaaagccg ttctggttaa catcttcggc 960ggtatcgttc
gttgcgacct gatcgctgac ggtatcatcg gcgcggtagc agaagtgggt
1020gttaacgtac cggtcgtggt acgtctggaa ggtaacaacg ccgaactcgg
cgcgaagaaa 1080ctggctgaca gcggcctgaa tattattgca gcaaaaggtc
tgacggatgc agctcagcag 1140gttgttgccg cagtggaggg gaaataatgt
ccattttaat cgataaaaac accaaggtta 1200tctgccaggg ctttaccggt
agccagggga ctttccactc agaacaggcc attgcatacg 1260gcactaaaat
ggttggcggc gtaaccccag gtaaaggcgg caccacccac ctcggcctgc
1320cggtgttcaa caccgtgcgt gaagccgttg ctgccactgg cgctaccgct
tctgttatct 1380acgtaccagc accgttctgc aaagactcca ttctggaagc
catcgacgca ggcatcaaac 1440tgattatcac catcactgaa ggcatcccga
cgctggatat gctgaccgtg aaagtgaagc 1500tggatgaagc aggcgttcgt
atgatcggcc cgaactgccc aggcgttatc actccgggtg 1560aatgcaaaat
cggtatccag cctggtcaca ttcacaaacc gggtaaagtg ggtatcgttt
1620cccgttccgg tacactgacc tatgaagcgg ttaaacagac cacggattac
ggtttcggtc 1680agtcgacctg tgtcggtatc ggcggtgacc cgatcccggg
ctctaacttt atcgacattc 1740tcgaaatgtt cgaaaaagat ccgcagaccg
aagcgatcgt gatgatcggt gagatcggcg 1800gtagcgctga agaagaagca
gctgcgtaca tcaaagagca cgttaccaag ccagttgtgg 1860gttacatcgc
tggtgtgact gcgccgaaag gcaaacgtat gggccacgcg ggtgccatca
1920ttgccggtgg gaaagggact gcggatgaga aattcgctgc tctggaagcc
gcaggcgtga 1980aaaccgttcg cagcctggcg gatatcggtg aagcactgaa
aactgttctg aaataa 203647388PRTEscherichia coli 47Met Asn Leu His
Glu Tyr Gln Ala Lys Gln Leu Phe Ala Arg Tyr Gly 1 5 10 15 Leu Pro
Ala Pro Val Gly Tyr Ala Cys Thr Thr Pro Arg Glu Ala Glu 20 25 30
Glu Ala Ala Ser Lys Ile Gly Ala Gly Pro Trp Val Val Lys Cys Gln 35
40 45 Val His Ala Gly Gly Arg Gly Lys Ala Gly Gly Val Lys Val Val
Asn 50 55 60 Ser Lys Glu Asp Ile Arg Ala Phe Ala Glu Asn Trp Leu
Gly Lys Arg 65 70 75 80 Leu Val Thr Tyr Gln Thr Asp Ala Asn Gly Gln
Pro Val Asn Gln Ile 85 90 95 Leu Val Glu Ala Ala Thr Asp Ile Ala
Lys Glu Leu Tyr Leu Gly Ala 100 105 110 Val Val Asp Arg Ser Ser Arg
Arg Val Val Phe Met Ala Ser Thr Glu 115 120 125 Gly Gly Val Glu Ile
Glu Lys Val Ala Glu Glu Thr Pro His Leu Ile 130 135 140 His Lys Val
Ala Leu Asp Pro Leu Thr Gly Pro Met Pro Tyr Gln Gly 145 150 155 160
Arg Glu Leu Ala Phe Lys Leu Gly Leu Glu Gly Lys Leu Val Gln Gln 165
170 175 Phe Thr Lys Ile Phe Met Gly Leu Ala Thr Ile Phe Leu Glu Arg
Asp 180 185 190 Leu Ala Leu Ile Glu Ile Asn Pro Leu Val Ile Thr Lys
Gln Gly Asp 195 200 205 Leu Ile Cys Leu Asp Gly Lys Leu Gly Ala Asp
Gly Asn Ala Leu Phe 210 215 220 Arg Gln Pro Asp Leu Arg Glu Met Arg
Asp Gln Ser Gln Glu Asp Pro 225 230 235 240 Arg Glu Ala Gln Ala Ala
Gln Trp Glu Leu Asn Tyr Val Ala Leu Asp 245 250 255 Gly Asn Ile Gly
Cys Met Val Asn Gly Ala Gly Leu Ala Met Gly Thr 260 265 270 Met Asp
Ile Val Lys Leu His Gly Gly Glu Pro Ala Asn Phe Leu Asp 275 280 285
Val Gly Gly Gly Ala Thr Lys Glu Arg Val Thr Glu Ala Phe Lys Ile 290
295 300 Ile Leu Ser Asp Asp Lys Val Lys Ala Val Leu Val Asn Ile Phe
Gly 305 310 315 320 Gly Ile Val Arg Cys Asp Leu Ile Ala Asp Gly Ile
Ile Gly Ala Val 325 330 335 Ala Glu Val Gly Val Asn Val Pro Val Val
Val Arg Leu Glu Gly Asn 340 345 350 Asn Ala Glu Leu Gly Ala Lys Lys
Leu Ala Asp Ser Gly Leu Asn Ile 355 360 365 Ile Ala Ala Lys Gly Leu
Thr Asp Ala Ala Gln Gln Val Val Ala Ala 370 375 380 Val Glu Gly Lys
385 48289PRTEscherichia coli 48Met Ser Ile Leu Ile Asp Lys Asn Thr
Lys Val Ile Cys Gln Gly Phe 1 5 10 15 Thr Gly Ser Gln Gly Thr Phe
His Ser Glu Gln Ala Ile Ala Tyr Gly 20 25 30 Thr Lys Met Val Gly
Gly Val Thr Pro Gly Lys Gly Gly Thr Thr His 35 40 45 Leu Gly Leu
Pro Val Phe Asn Thr Val Arg Glu Ala Val Ala Ala Thr 50 55 60 Gly
Ala Thr Ala Ser Val Ile Tyr Val Pro Ala Pro Phe Cys Lys Asp 65 70
75 80 Ser Ile Leu Glu Ala Ile Asp Ala Gly Ile Lys Leu Ile Ile Thr
Ile 85 90 95 Thr Glu Gly Ile Pro Thr Leu Asp Met Leu Thr Val Lys
Val Lys Leu 100 105 110 Asp Glu Ala Gly Val Arg Met Ile Gly Pro Asn
Cys Pro Gly Val Ile 115 120 125 Thr Pro Gly Glu Cys Lys Ile Gly Ile
Gln Pro Gly His Ile His Lys 130 135 140 Pro Gly Lys Val Gly Ile Val
Ser Arg Ser Gly Thr Leu Thr Tyr Glu 145 150 155 160 Ala Val Lys Gln
Thr Thr Asp Tyr Gly Phe Gly Gln Ser Thr Cys Val 165 170 175 Gly Ile
Gly Gly Asp Pro Ile Pro Gly Ser Asn Phe Ile Asp Ile Leu 180 185 190
Glu Met Phe Glu Lys Asp Pro Gln Thr Glu Ala Ile Val Met Ile Gly 195
200 205 Glu Ile Gly Gly Ser Ala Glu Glu Glu Ala Ala Ala Tyr Ile Lys
Glu 210 215 220 His Val Thr Lys Pro Val Val Gly Tyr Ile Ala Gly Val
Thr Ala Pro 225 230 235 240 Lys Gly Lys Arg Met Gly His Ala Gly Ala
Ile Ile Ala Gly Gly Lys 245 250 255 Gly Thr Ala Asp Glu Lys Phe Ala
Ala Leu Glu Ala Ala Gly Val Lys 260 265 270 Thr Val Arg Ser Leu Ala
Asp Ile Gly Glu Ala Leu Lys Thr Val Leu 275 280 285 Lys
493696DNAMycobacterium bovis 49atggccaaca taagttcacc attcgggcaa
aacgaatggc tggttgaaga gatgtaccgc 60aagttccgcg acgacccctc ctcggtcgat
cccagctggc acgagttcct ggttgactac 120agccccgaac ccacctccca
accagctgcc gaaccaaccc gggttacctc gccactcgtt 180gccgagcggg
ccgctgcggc cgccccgcag gcacccccca agccggccga caccgcggcc
240gcgggcaacg gcgtggtcgc cgcactggcc gccaaaactg ccgttccccc
gccagccgaa 300ggtgacgagg tagcggtgct gcgcggcgcc gccgcggccg
tcgtcaagaa catgtccgcg 360tcgttggagg tgccgacggc gaccagcgtc
cgggcggtcc cggccaagct actgatcgac 420aaccggatcg tcatcaacaa
ccagttgaag cggacccgcg gcggcaagat ctcgttcacg 480catttgctgg
gctacgccct ggtgcaggcg gtgaagaaat tcccgaacat gaaccggcac
540tacaccgaag tcgacggcaa gcccaccgcg gtcacgccgg cgcacaccaa
tctcggcctg 600gcgatcgacc tgcaaggcaa ggacgggaag cgttccctgg
tggtggccgg catcaagcgg 660tgcgagacca tgcgattcgc gcagttcgtc
acggcctacg aagacatcgt acgccgggcc 720cgcgacggca agctgaccac
tgaagacttt gccggcgtga cgatttcgct gaccaatccc 780ggaaccatcg
gcaccgtgca ttcggtgccg cggctgatgc ccggccaggg cgccatcatc
840ggcgtgggcg ccatggaata ccccgccgag tttcaaggcg ccagcgagga
acgcatcgcc 900gagctgggca tcggcaaatt gatcactttg acctccacct
acgaccaccg catcatccag 960ggcgcggaat cgggcgactt cctgcgcacc
atccacgagt tgctgctctc ggatggcttc 1020tgggacgagg tcttccgcga
actgagcatc ccatatctgc cggtgcgctg gagcaccgac 1080aaccccgact
cgatcgtcga caagaacgct cgcgtcatga acttgatcgc ggcctaccgc
1140aaccgcggcc atctgatggc cgataccgac ccgctgcggt tggacaaagc
tcggttccgc 1200agtcaccccg acctcgaagt gctgacccac ggcctgacgc
tgtgggatct cgatcgggtg 1260ttcaaggtcg acggctttgc cggtgcgcag
tacaagaaac tgcgcgacgt gctgggcttg 1320ctgcgcgatg cctactgccg
ccacatcggc gtggagtacg cccatatcct cgaccccgaa 1380caaaaggagt
ggctcgaaca acgggtcgag accaagcacg tcaaacccac tgtggcccaa
1440cagaaataca tcctcagcaa gctcaacgcc gccgaggcct ttgaaacgtt
cctacagacc 1500aagtacgtcg gccagaagcg gttctcgctg gaaggcgccg
aaagcgtgat cccgatgatg 1560gacgcggcga tcgaccagtg cgctgagcac
ggcctcgacg aggtggtcat cgggatgccg 1620caccggggcc ggctcaacgt
gctggccaac atcgtcggca agccgtactc gcagatcttc 1680accgagttcg
agggcaacct gaatccgtcg caggcgcacg gctccggtga cgtcaagtac
1740cacctgggcg ccaccgggct gtacctgcag atgttcggcg acaacgacat
tcaggtgtcg 1800ctgaccgcca acccgtcgca tctggaggcc gtcgacccgg
tgctggaggg attggtgcgg 1860gccaagcagg atctgctcga ccacggaagc
atcgacagcg acggccaacg ggcgttctcg 1920gtggtgccgc tgatgttgca
tggcgatgcc gcgttcgccg gtcagggtgt ggtcgccgag 1980acgctgaacc
tggcgaatct gccgggctac cgcgtcggcg gcaccatcca catcatcgtc
2040aacaaccaga
tcggcttcac caccgcgccc gagtattcca ggtccagcga gtactgcacc
2100gacgtcgcaa agatgatcgg ggcaccgatc tttcacgtca acggcgacga
cccggaggcg 2160tgtgtctggg tggcgcggtt ggcggtggac ttccgacaac
ggttcaagaa ggacgtcgtc 2220atcgacatgc tgtgctaccg ccgccgcggg
cacaacgagg gtgacgaccc gtcgatgacc 2280aacccctaca tgtacgacgt
cgtcgacacc aagcgcgggg cccgcaaaag ctacaccgaa 2340gccctgatcg
gacgtggcga catctcgatg aaggaggccg aggacgcgct gcgcgactac
2400cagggccagc tggaacgggt gttcaacgaa gtgcgcgagc tggagaagca
cggtgtgcag 2460ccgagcgagt cggtcgagtc cgaccagatg attcccgcgg
ggctggccac tgcggtggac 2520aagtcgctgc tggcccggat cggcgatgcg
ttcctcgcct tgccgaacgg cttcaccgcg 2580cacccgcgag tccaaccggt
gctggagaag cgccgggaga tggcctatga aggcaagatc 2640gactgggcct
ttggcgagct gctggcgctg ggctcgctgg tggccgaagg caagctggtg
2700cgcttgtcgg ggcaggacag ccgccgcggc accttctccc agcggcattc
ggttctcatc 2760gaccgccaca ctggcgagga gttcacacca ctgcagctgc
tggcgaccaa ctccgacggc 2820agcccgaccg gcggaaagtt cctggtctac
gactcgccac tgtcggagta cgccgccgtc 2880ggcttcgagt acggctacac
tgtgggcaat ccggacgccg tggtgctctg ggaggcgcag 2940ttcggcgact
tcgtcaacgg cgcacagtcg atcatcgacg agttcatcag ctccggtgag
3000gccaagtggg gccaattgtc caacgtcgtg ctgctgttac cgcacgggca
cgaggggcag 3060ggacccgacc acacttctgc ccggatcgaa cgcttcttgc
agttgtgggc ggaaggttcg 3120atgaccatcg cgatgccgtc gactccgtcg
aactacttcc acctgctacg ccggcatgcc 3180ctggacggca tccaacgccc
gctgatcgtg ttcacgccca agtcgatgtt gcgtcacaag 3240gccgccgtca
gcgaaatcaa ggacttcacc gagatcaagt tccgctcagt gctggaggaa
3300cccacctatg aggacggcat cggagaccgc aacaaggtca gccggatcct
gctgaccagt 3360ggcaagctgt attacgagct ggccgcccgc aaggccaagg
acaaccgcaa tgacctcgcg 3420atcgtgcggc ttgaacagct cgccccgctg
cccaggcgtc gactgcgtga aacgctggac 3480cgctacgaga acgtcaagga
gttcttctgg gtccaagagg aaccggccaa ccagggtgcg 3540tggccgcgat
tcgggctcga actacccgag ctgctgcctg acaagttggc cgggatcaag
3600cgaatctcgc gccgggcgat gtcagccccg tcgtcaggct cgtcgaaggt
gcacgccgtc 3660gaacagcagg agatcctcga cgaggcgttc ggctaa
3696501231PRTMycobacterium bovis 50Met Ala Asn Ile Ser Ser Pro Phe
Gly Gln Asn Glu Trp Leu Val Glu 1 5 10 15 Glu Met Tyr Arg Lys Phe
Arg Asp Asp Pro Ser Ser Val Asp Pro Ser 20 25 30 Trp His Glu Phe
Leu Val Asp Tyr Ser Pro Glu Pro Thr Ser Gln Pro 35 40 45 Ala Ala
Glu Pro Thr Arg Val Thr Ser Pro Leu Val Ala Glu Arg Ala 50 55 60
Ala Ala Ala Ala Pro Gln Ala Pro Pro Lys Pro Ala Asp Thr Ala Ala 65
70 75 80 Ala Gly Asn Gly Val Val Ala Ala Leu Ala Ala Lys Thr Ala
Val Pro 85 90 95 Pro Pro Ala Glu Gly Asp Glu Val Ala Val Leu Arg
Gly Ala Ala Ala 100 105 110 Ala Val Val Lys Asn Met Ser Ala Ser Leu
Glu Val Pro Thr Ala Thr 115 120 125 Ser Val Arg Ala Val Pro Ala Lys
Leu Leu Ile Asp Asn Arg Ile Val 130 135 140 Ile Asn Asn Gln Leu Lys
Arg Thr Arg Gly Gly Lys Ile Ser Phe Thr 145 150 155 160 His Leu Leu
Gly Tyr Ala Leu Val Gln Ala Val Lys Lys Phe Pro Asn 165 170 175 Met
Asn Arg His Tyr Thr Glu Val Asp Gly Lys Pro Thr Ala Val Thr 180 185
190 Pro Ala His Thr Asn Leu Gly Leu Ala Ile Asp Leu Gln Gly Lys Asp
195 200 205 Gly Lys Arg Ser Leu Val Val Ala Gly Ile Lys Arg Cys Glu
Thr Met 210 215 220 Arg Phe Ala Gln Phe Val Thr Ala Tyr Glu Asp Ile
Val Arg Arg Ala 225 230 235 240 Arg Asp Gly Lys Leu Thr Thr Glu Asp
Phe Ala Gly Val Thr Ile Ser 245 250 255 Leu Thr Asn Pro Gly Thr Ile
Gly Thr Val His Ser Val Pro Arg Leu 260 265 270 Met Pro Gly Gln Gly
Ala Ile Ile Gly Val Gly Ala Met Glu Tyr Pro 275 280 285 Ala Glu Phe
Gln Gly Ala Ser Glu Glu Arg Ile Ala Glu Leu Gly Ile 290 295 300 Gly
Lys Leu Ile Thr Leu Thr Ser Thr Tyr Asp His Arg Ile Ile Gln 305 310
315 320 Gly Ala Glu Ser Gly Asp Phe Leu Arg Thr Ile His Glu Leu Leu
Leu 325 330 335 Ser Asp Gly Phe Trp Asp Glu Val Phe Arg Glu Leu Ser
Ile Pro Tyr 340 345 350 Leu Pro Val Arg Trp Ser Thr Asp Asn Pro Asp
Ser Ile Val Asp Lys 355 360 365 Asn Ala Arg Val Met Asn Leu Ile Ala
Ala Tyr Arg Asn Arg Gly His 370 375 380 Leu Met Ala Asp Thr Asp Pro
Leu Arg Leu Asp Lys Ala Arg Phe Arg 385 390 395 400 Ser His Pro Asp
Leu Glu Val Leu Thr His Gly Leu Thr Leu Trp Asp 405 410 415 Leu Asp
Arg Val Phe Lys Val Asp Gly Phe Ala Gly Ala Gln Tyr Lys 420 425 430
Lys Leu Arg Asp Val Leu Gly Leu Leu Arg Asp Ala Tyr Cys Arg His 435
440 445 Ile Gly Val Glu Tyr Ala His Ile Leu Asp Pro Glu Gln Lys Glu
Trp 450 455 460 Leu Glu Gln Arg Val Glu Thr Lys His Val Lys Pro Thr
Val Ala Gln 465 470 475 480 Gln Lys Tyr Ile Leu Ser Lys Leu Asn Ala
Ala Glu Ala Phe Glu Thr 485 490 495 Phe Leu Gln Thr Lys Tyr Val Gly
Gln Lys Arg Phe Ser Leu Glu Gly 500 505 510 Ala Glu Ser Val Ile Pro
Met Met Asp Ala Ala Ile Asp Gln Cys Ala 515 520 525 Glu His Gly Leu
Asp Glu Val Val Ile Gly Met Pro His Arg Gly Arg 530 535 540 Leu Asn
Val Leu Ala Asn Ile Val Gly Lys Pro Tyr Ser Gln Ile Phe 545 550 555
560 Thr Glu Phe Glu Gly Asn Leu Asn Pro Ser Gln Ala His Gly Ser Gly
565 570 575 Asp Val Lys Tyr His Leu Gly Ala Thr Gly Leu Tyr Leu Gln
Met Phe 580 585 590 Gly Asp Asn Asp Ile Gln Val Ser Leu Thr Ala Asn
Pro Ser His Leu 595 600 605 Glu Ala Val Asp Pro Val Leu Glu Gly Leu
Val Arg Ala Lys Gln Asp 610 615 620 Leu Leu Asp His Gly Ser Ile Asp
Ser Asp Gly Gln Arg Ala Phe Ser 625 630 635 640 Val Val Pro Leu Met
Leu His Gly Asp Ala Ala Phe Ala Gly Gln Gly 645 650 655 Val Val Ala
Glu Thr Leu Asn Leu Ala Asn Leu Pro Gly Tyr Arg Val 660 665 670 Gly
Gly Thr Ile His Ile Ile Val Asn Asn Gln Ile Gly Phe Thr Thr 675 680
685 Ala Pro Glu Tyr Ser Arg Ser Ser Glu Tyr Cys Thr Asp Val Ala Lys
690 695 700 Met Ile Gly Ala Pro Ile Phe His Val Asn Gly Asp Asp Pro
Glu Ala 705 710 715 720 Cys Val Trp Val Ala Arg Leu Ala Val Asp Phe
Arg Gln Arg Phe Lys 725 730 735 Lys Asp Val Val Ile Asp Met Leu Cys
Tyr Arg Arg Arg Gly His Asn 740 745 750 Glu Gly Asp Asp Pro Ser Met
Thr Asn Pro Tyr Met Tyr Asp Val Val 755 760 765 Asp Thr Lys Arg Gly
Ala Arg Lys Ser Tyr Thr Glu Ala Leu Ile Gly 770 775 780 Arg Gly Asp
Ile Ser Met Lys Glu Ala Glu Asp Ala Leu Arg Asp Tyr 785 790 795 800
Gln Gly Gln Leu Glu Arg Val Phe Asn Glu Val Arg Glu Leu Glu Lys 805
810 815 His Gly Val Gln Pro Ser Glu Ser Val Glu Ser Asp Gln Met Ile
Pro 820 825 830 Ala Gly Leu Ala Thr Ala Val Asp Lys Ser Leu Leu Ala
Arg Ile Gly 835 840 845 Asp Ala Phe Leu Ala Leu Pro Asn Gly Phe Thr
Ala His Pro Arg Val 850 855 860 Gln Pro Val Leu Glu Lys Arg Arg Glu
Met Ala Tyr Glu Gly Lys Ile 865 870 875 880 Asp Trp Ala Phe Gly Glu
Leu Leu Ala Leu Gly Ser Leu Val Ala Glu 885 890 895 Gly Lys Leu Val
Arg Leu Ser Gly Gln Asp Ser Arg Arg Gly Thr Phe 900 905 910 Ser Gln
Arg His Ser Val Leu Ile Asp Arg His Thr Gly Glu Glu Phe 915 920 925
Thr Pro Leu Gln Leu Leu Ala Thr Asn Ser Asp Gly Ser Pro Thr Gly 930
935 940 Gly Lys Phe Leu Val Tyr Asp Ser Pro Leu Ser Glu Tyr Ala Ala
Val 945 950 955 960 Gly Phe Glu Tyr Gly Tyr Thr Val Gly Asn Pro Asp
Ala Val Val Leu 965 970 975 Trp Glu Ala Gln Phe Gly Asp Phe Val Asn
Gly Ala Gln Ser Ile Ile 980 985 990 Asp Glu Phe Ile Ser Ser Gly Glu
Ala Lys Trp Gly Gln Leu Ser Asn 995 1000 1005 Val Val Leu Leu Leu
Pro His Gly His Glu Gly Gln Gly Pro Asp 1010 1015 1020 His Thr Ser
Ala Arg Ile Glu Arg Phe Leu Gln Leu Trp Ala Glu 1025 1030 1035 Gly
Ser Met Thr Ile Ala Met Pro Ser Thr Pro Ser Asn Tyr Phe 1040 1045
1050 His Leu Leu Arg Arg His Ala Leu Asp Gly Ile Gln Arg Pro Leu
1055 1060 1065 Ile Val Phe Thr Pro Lys Ser Met Leu Arg His Lys Ala
Ala Val 1070 1075 1080 Ser Glu Ile Lys Asp Phe Thr Glu Ile Lys Phe
Arg Ser Val Leu 1085 1090 1095 Glu Glu Pro Thr Tyr Glu Asp Gly Ile
Gly Asp Arg Asn Lys Val 1100 1105 1110 Ser Arg Ile Leu Leu Thr Ser
Gly Lys Leu Tyr Tyr Glu Leu Ala 1115 1120 1125 Ala Arg Lys Ala Lys
Asp Asn Arg Asn Asp Leu Ala Ile Val Arg 1130 1135 1140 Leu Glu Gln
Leu Ala Pro Leu Pro Arg Arg Arg Leu Arg Glu Thr 1145 1150 1155 Leu
Asp Arg Tyr Glu Asn Val Lys Glu Phe Phe Trp Val Gln Glu 1160 1165
1170 Glu Pro Ala Asn Gln Gly Ala Trp Pro Arg Phe Gly Leu Glu Leu
1175 1180 1185 Pro Glu Leu Leu Pro Asp Lys Leu Ala Gly Ile Lys Arg
Ile Ser 1190 1195 1200 Arg Arg Ala Met Ser Ala Pro Ser Ser Gly Ser
Ser Lys Val His 1205 1210 1215 Ala Val Glu Gln Gln Glu Ile Leu Asp
Glu Ala Phe Gly 1220 1225 1230 511356DNAPorphyromonas gingivalis
51atggaaatca aagaaatggt gagccttgca cgcaaggctc agaaggagta tcaagctacc
60cataaccaag aagcagttga caacatttgc cgagctgcag caaaagttat ttatgaaaat
120gcagctattc tggctcgcga agcagtagac gaaaccggca tgggcgttta
cgaacacaaa 180gtggccaaga atcaaggcaa atccaaaggt gtttggtaca
acctccacaa taaaaaatcg 240attggtatcc tcaatataga cgagcgtacc
ggtatgatcg agattgcaaa gcctatcgga 300gttgtaggag ccgtaacgcc
gacgaccaac ccgatcgtta ctccgatgag caatatcatc 360tttgctctta
agacctgcaa tgccatcatt attgcccccc accccagatc caaaaaatgc
420tctgcacacg cagttcgtct gatcaaagaa gctatcgctc cgttcaacgt
accggaaggt 480atggttcaga tcatcgaaga acccagcatc gagaagacgc
aggaactcat gggcgccgta 540gacgtagtag ttgctacggg tggtatgggc
atggtgaagt ctgcatattc ttcaggaaag 600ccttctttcg gtgttggagc
cggtaacgtt caggtgatcg tggatagcaa catcgatttc 660gaagctgctg
cagaaaaaat catcaccggt cgtgctttcg acaacggtat catctgctca
720ggcgaacaga gcatcatcta caacgaggct gacaaggaag cagttttcac
agcattccgc 780aaccacggtg catatttctg tgacgaagcc gaaggagatc
gggctcgtgc agctatcttc 840gaaaatggag ccatcgcgaa agatgtagta
ggtcagagcg ttgccttcat tgccaagaaa 900gcaaacatca atatccccga
gggtacccgt attctcgttg ttgaagctcg cggcgtagga 960gcagaagacg
ttatctgtaa ggaaaagatg tgtcccgtaa tgtgcgccct cagctacaag
1020cacttcgaag aaggtgtaga aatcgcacgt acgaacctcg ccaacgaagg
taacggccac 1080acctgtgcta tccactccaa caatcaggca cacatcatcc
tcgcaggatc agagctgacg 1140gtatctcgta tcgtagtgaa tgctccgagt
gccactacag caggcggtca catccaaaac 1200ggtcttgccg taaccaatac
gctcggatgc ggatcatggg gtaataactc tatctccgag 1260aacttcactt
acaagcacct cctcaacatt tcacgcatcg caccgttgaa ttcaagcatt
1320cacatccccg atgacaaaga aatctgggaa ctctaa
135652451PRTPorphyromonas gingivalis 52Met Glu Ile Lys Glu Met Val
Ser Leu Ala Arg Lys Ala Gln Lys Glu 1 5 10 15 Tyr Gln Ala Thr His
Asn Gln Glu Ala Val Asp Asn Ile Cys Arg Ala 20 25 30 Ala Ala Lys
Val Ile Tyr Glu Asn Ala Ala Ile Leu Ala Arg Glu Ala 35 40 45 Val
Asp Glu Thr Gly Met Gly Val Tyr Glu His Lys Val Ala Lys Asn 50 55
60 Gln Gly Lys Ser Lys Gly Val Trp Tyr Asn Leu His Asn Lys Lys Ser
65 70 75 80 Ile Gly Ile Leu Asn Ile Asp Glu Arg Thr Gly Met Ile Glu
Ile Ala 85 90 95 Lys Pro Ile Gly Val Val Gly Ala Val Thr Pro Thr
Thr Asn Pro Ile 100 105 110 Val Thr Pro Met Ser Asn Ile Ile Phe Ala
Leu Lys Thr Cys Asn Ala 115 120 125 Ile Ile Ile Ala Pro His Pro Arg
Ser Lys Lys Cys Ser Ala His Ala 130 135 140 Val Arg Leu Ile Lys Glu
Ala Ile Ala Pro Phe Asn Val Pro Glu Gly 145 150 155 160 Met Val Gln
Ile Ile Glu Glu Pro Ser Ile Glu Lys Thr Gln Glu Leu 165 170 175 Met
Gly Ala Val Asp Val Val Val Ala Thr Gly Gly Met Gly Met Val 180 185
190 Lys Ser Ala Tyr Ser Ser Gly Lys Pro Ser Phe Gly Val Gly Ala Gly
195 200 205 Asn Val Gln Val Ile Val Asp Ser Asn Ile Asp Phe Glu Ala
Ala Ala 210 215 220 Glu Lys Ile Ile Thr Gly Arg Ala Phe Asp Asn Gly
Ile Ile Cys Ser 225 230 235 240 Gly Glu Gln Ser Ile Ile Tyr Asn Glu
Ala Asp Lys Glu Ala Val Phe 245 250 255 Thr Ala Phe Arg Asn His Gly
Ala Tyr Phe Cys Asp Glu Ala Glu Gly 260 265 270 Asp Arg Ala Arg Ala
Ala Ile Phe Glu Asn Gly Ala Ile Ala Lys Asp 275 280 285 Val Val Gly
Gln Ser Val Ala Phe Ile Ala Lys Lys Ala Asn Ile Asn 290 295 300 Ile
Pro Glu Gly Thr Arg Ile Leu Val Val Glu Ala Arg Gly Val Gly 305 310
315 320 Ala Glu Asp Val Ile Cys Lys Glu Lys Met Cys Pro Val Met Cys
Ala 325 330 335 Leu Ser Tyr Lys His Phe Glu Glu Gly Val Glu Ile Ala
Arg Thr Asn 340 345 350 Leu Ala Asn Glu Gly Asn Gly His Thr Cys Ala
Ile His Ser Asn Asn 355 360 365 Gln Ala His Ile Ile Leu Ala Gly Ser
Glu Leu Thr Val Ser Arg Ile 370 375 380 Val Val Asn Ala Pro Ser Ala
Thr Thr Ala Gly Gly His Ile Gln Asn 385 390 395 400 Gly Leu Ala Val
Thr Asn Thr Leu Gly Cys Gly Ser Trp Gly Asn Asn 405 410 415 Ser Ile
Ser Glu Asn Phe Thr Tyr Lys His Leu Leu Asn Ile Ser Arg 420 425 430
Ile Ala Pro Leu Asn Ser Ser Ile His Ile Pro Asp Asp Lys Glu Ile 435
440 445 Trp Glu Leu 450 531116DNAPorphyromonas gingivalis
53atgcaacttt tcaaactcaa gagtgtaaca catcactttg acacttttgc agaatttgcc
60aaggaattct gtcttggaga acgcgacttg gtaattacca acgagttcat ctatgaaccg
120tatatgaagg catgccagct cccctgccat tttgttatgc aggagaaata
tgggcaaggc 180gagccttctg acgaaatgat gaataacatc ttggcagaca
tccgtaatat ccagttcgac 240cgcgtaatcg gtatcggagg aggtacggtt
attgacatct ctaaactttt cgttctgaaa 300ggattaaatg atgtactcga
tgcattcgac cgcaaaatac ctcttatcaa agagaaagaa 360ctgatcattg
tgcccacaac atgcggaacg ggtagcgagg tgacgaacat ttctatcgca
420gaaatcaaaa gccgtcacac caaaatggga ttggctgacg atgccattgt
tgcagaccat 480gccatcatca tacctgaact tctgaagagc ttgcctttcc
acttctacgc atgcagtgca 540atcgatgctc ttatccatgc catcgagtca
tacgtatctc ctaaagccag tccatattct 600cgtctgttca gtgaggcggc
ttgggacatt atcctggaag tattcaagaa aatcgccgaa 660cacggccctg
aataccgctt cgaaaagctg ggagaaatga tcatggccag caactatgcc
720ggtatagcct tcggaaatgc aggagtagga gccgtccacg cactatccta
cccgttggga 780ggcaactatc acgtgccgca tggagaagca
aactatcagt tcttcacaga ggtattcaaa 840gtataccaaa agaagaatcc
tttcggctat atagtcgaac tcaactggaa gctctccaag 900atactgaact
gccagcccga atacgtatat ccgaagctgg atgaacttct cggatgcctt
960cttaccaaga aacctttgca cgaatacggc atgaaggacg aagaggtaag
aggctttgcg 1020gaatcagtgc ttaagacaca gcaaagattg ctcgccaaca
actacgtaga gcttactgta 1080gatgagatcg aaggtatcta cagaagactc tactaa
111654371PRTPorphyromonas gingivalis 54Met Gln Leu Phe Lys Leu Lys
Ser Val Thr His His Phe Asp Thr Phe 1 5 10 15 Ala Glu Phe Ala Lys
Glu Phe Cys Leu Gly Glu Arg Asp Leu Val Ile 20 25 30 Thr Asn Glu
Phe Ile Tyr Glu Pro Tyr Met Lys Ala Cys Gln Leu Pro 35 40 45 Cys
His Phe Val Met Gln Glu Lys Tyr Gly Gln Gly Glu Pro Ser Asp 50 55
60 Glu Met Met Asn Asn Ile Leu Ala Asp Ile Arg Asn Ile Gln Phe Asp
65 70 75 80 Arg Val Ile Gly Ile Gly Gly Gly Thr Val Ile Asp Ile Ser
Lys Leu 85 90 95 Phe Val Leu Lys Gly Leu Asn Asp Val Leu Asp Ala
Phe Asp Arg Lys 100 105 110 Ile Pro Leu Ile Lys Glu Lys Glu Leu Ile
Ile Val Pro Thr Thr Cys 115 120 125 Gly Thr Gly Ser Glu Val Thr Asn
Ile Ser Ile Ala Glu Ile Lys Ser 130 135 140 Arg His Thr Lys Met Gly
Leu Ala Asp Asp Ala Ile Val Ala Asp His 145 150 155 160 Ala Ile Ile
Ile Pro Glu Leu Leu Lys Ser Leu Pro Phe His Phe Tyr 165 170 175 Ala
Cys Ser Ala Ile Asp Ala Leu Ile His Ala Ile Glu Ser Tyr Val 180 185
190 Ser Pro Lys Ala Ser Pro Tyr Ser Arg Leu Phe Ser Glu Ala Ala Trp
195 200 205 Asp Ile Ile Leu Glu Val Phe Lys Lys Ile Ala Glu His Gly
Pro Glu 210 215 220 Tyr Arg Phe Glu Lys Leu Gly Glu Met Ile Met Ala
Ser Asn Tyr Ala 225 230 235 240 Gly Ile Ala Phe Gly Asn Ala Gly Val
Gly Ala Val His Ala Leu Ser 245 250 255 Tyr Pro Leu Gly Gly Asn Tyr
His Val Pro His Gly Glu Ala Asn Tyr 260 265 270 Gln Phe Phe Thr Glu
Val Phe Lys Val Tyr Gln Lys Lys Asn Pro Phe 275 280 285 Gly Tyr Ile
Val Glu Leu Asn Trp Lys Leu Ser Lys Ile Leu Asn Cys 290 295 300 Gln
Pro Glu Tyr Val Tyr Pro Lys Leu Asp Glu Leu Leu Gly Cys Leu 305 310
315 320 Leu Thr Lys Lys Pro Leu His Glu Tyr Gly Met Lys Asp Glu Glu
Val 325 330 335 Arg Gly Phe Ala Glu Ser Val Leu Lys Thr Gln Gln Arg
Leu Leu Ala 340 345 350 Asn Asn Tyr Val Glu Leu Thr Val Asp Glu Ile
Glu Gly Ile Tyr Arg 355 360 365 Arg Leu Tyr 370
551296DNAPorphyromonas gingivalis 55atgaaagacg tattagcgga
atatgcctcc cgaattgttt cggccgaaga agccgtaaaa 60catatcaaaa atggagaacg
ggtagctttg tcacatgctg ccggagttcc tcagagttgt 120gttgatgcac
tggtacaaca ggccgacctt ttccagaatg tcgaaattta tcacatgctt
180tgtctcggcg aaggaaaata tatggcacct gaaatggccc ctcacttccg
acacataacc 240aattttgtag gtggtaattc tcgtaaagca gttgaggaaa
atagagccga cttcattccg 300gtattctttt atgaagtgcc atcaatgatt
cgcaaagaca tccttcacat agatgtcgcc 360atcgttcagc tttcaatgcc
tgatgagaat ggttactgta gttttggagt atcttgcgat 420tatagcaaac
cggcagcaga aagcgctcat ttagttatag gggaaatcaa ccgtcaaatg
480ccatatgtac atggcgacaa cttgattcac atatcgaagt tggattacat
cgtgatggca 540gactacccta tctattctct tgcaaagccc aaaatcggag
aagtagaaga agctatcggg 600cgtaattgtg ccgagcttat tgaagatggt
gccacactcc aactcggtat cggcgcgatt 660cctgatgcag ccctgttatt
cctcaaggac aaaaaagatc tggggatcca taccgagatg 720ttctccgatg
gtgttgtcga attagttcgc agtggagtaa ttacaggaaa gaaaaagaca
780cttcaccccg gaaagatggt cgcaaccttc ttaatgggaa gcgaagacgt
atatcatttc 840atcgacaaaa atcccgatgt agaactttat ccggtagatt
acgtcaatga tccgcgagta 900atcgctcaaa atgataatat ggtcagcatc
aatagctgta tcgaaatcga tcttatggga 960caagtcgtgt ccgaatgtat
aggaagcaag caattcagcg gaaccggcgg tcaagtagat 1020tatgttcgtg
gagcagcatg gtctaaaaac ggcaaaagca tcatggcaat tccctcaaca
1080gccaaaaacg gtactgcatc tcgaattgta cctataattg cagagggagc
tgctgtaaca 1140accctccgca acgaagtcga ttacgttgta accgaatacg
gtatagcaca actcaaagga 1200aagagtttgc gccagcgagc agaagctctt
attgccatag cccacccgga tttcagagag 1260gaactaacga aacatctccg
caaacgtttc ggataa 129656431PRTPorphyromonas gingivalis 56Met Lys
Asp Val Leu Ala Glu Tyr Ala Ser Arg Ile Val Ser Ala Glu 1 5 10 15
Glu Ala Val Lys His Ile Lys Asn Gly Glu Arg Val Ala Leu Ser His 20
25 30 Ala Ala Gly Val Pro Gln Ser Cys Val Asp Ala Leu Val Gln Gln
Ala 35 40 45 Asp Leu Phe Gln Asn Val Glu Ile Tyr His Met Leu Cys
Leu Gly Glu 50 55 60 Gly Lys Tyr Met Ala Pro Glu Met Ala Pro His
Phe Arg His Ile Thr 65 70 75 80 Asn Phe Val Gly Gly Asn Ser Arg Lys
Ala Val Glu Glu Asn Arg Ala 85 90 95 Asp Phe Ile Pro Val Phe Phe
Tyr Glu Val Pro Ser Met Ile Arg Lys 100 105 110 Asp Ile Leu His Ile
Asp Val Ala Ile Val Gln Leu Ser Met Pro Asp 115 120 125 Glu Asn Gly
Tyr Cys Ser Phe Gly Val Ser Cys Asp Tyr Ser Lys Pro 130 135 140 Ala
Ala Glu Ser Ala His Leu Val Ile Gly Glu Ile Asn Arg Gln Met 145 150
155 160 Pro Tyr Val His Gly Asp Asn Leu Ile His Ile Ser Lys Leu Asp
Tyr 165 170 175 Ile Val Met Ala Asp Tyr Pro Ile Tyr Ser Leu Ala Lys
Pro Lys Ile 180 185 190 Gly Glu Val Glu Glu Ala Ile Gly Arg Asn Cys
Ala Glu Leu Ile Glu 195 200 205 Asp Gly Ala Thr Leu Gln Leu Gly Ile
Gly Ala Ile Pro Asp Ala Ala 210 215 220 Leu Leu Phe Leu Lys Asp Lys
Lys Asp Leu Gly Ile His Thr Glu Met 225 230 235 240 Phe Ser Asp Gly
Val Val Glu Leu Val Arg Ser Gly Val Ile Thr Gly 245 250 255 Lys Lys
Lys Thr Leu His Pro Gly Lys Met Val Ala Thr Phe Leu Met 260 265 270
Gly Ser Glu Asp Val Tyr His Phe Ile Asp Lys Asn Pro Asp Val Glu 275
280 285 Leu Tyr Pro Val Asp Tyr Val Asn Asp Pro Arg Val Ile Ala Gln
Asn 290 295 300 Asp Asn Met Val Ser Ile Asn Ser Cys Ile Glu Ile Asp
Leu Met Gly 305 310 315 320 Gln Val Val Ser Glu Cys Ile Gly Ser Lys
Gln Phe Ser Gly Thr Gly 325 330 335 Gly Gln Val Asp Tyr Val Arg Gly
Ala Ala Trp Ser Lys Asn Gly Lys 340 345 350 Ser Ile Met Ala Ile Pro
Ser Thr Ala Lys Asn Gly Thr Ala Ser Arg 355 360 365 Ile Val Pro Ile
Ile Ala Glu Gly Ala Ala Val Thr Thr Leu Arg Asn 370 375 380 Glu Val
Asp Tyr Val Val Thr Glu Tyr Gly Ile Ala Gln Leu Lys Gly 385 390 395
400 Lys Ser Leu Arg Gln Arg Ala Glu Ala Leu Ile Ala Ile Ala His Pro
405 410 415 Asp Phe Arg Glu Glu Leu Thr Lys His Leu Arg Lys Arg Phe
Gly 420 425 430 57906DNAClostridium acetobutylicum 57atgattaaga
gttttaatga aattatcatg aaggtaaaga gcaaagaaat gaaaaaagtt 60gctgttgctg
tagcacaaga cgagccagta cttgaagcag taagagatgc taagaaaaat
120ggtattgcag atgctattct tgttggagac catgacgaaa tcgtgtcaat
cgcgcttaaa 180ataggaatgg atgtaaatga ttttgaaata gtaaacgagc
ctaacgttaa gaaagctgct 240ttaaaggcag tagagcttgt atcaactgga
aaagctgata tggtaatgaa gggacttgta 300aatacagcaa ctttcttaag
atctgtatta aacaaagaag ttggacttag aacaggaaaa 360actatgtctc
acgttgcagt atttgaaact gagaaatttg atagactatt atttttaaca
420gatgttgctt tcaatactta tcctgaatta aaggaaaaaa ttgatatagt
aaacaattca 480gttaaggttg cacatgcaat aggaattgaa aatccaaagg
ttgctccaat ttgtgcagtt 540gaggttataa accctaaaat gccatcaaca
cttgatgcag caatgctttc aaaaatgagt 600gacagaggac aaattaaagg
ttgtgtagtt gacggacctt tagcacttga tatagcttta 660tcagaagaag
cagcacatca taagggagta acaggagaag ttgctggaaa agctgatatc
720ttcttaatgc caaacataga aacaggaaat gtaatgtata agactttaac
atatacaact 780gattcaaaaa atggaggaat cttagttgga acttctgcac
cagttgtttt aacttcaaga 840gctgacagcc atgaaacaaa aatgaactct
atagcacttg cagctttagt tgcaggcaat 900aaataa 90658301PRTClostridium
acetobutylicum 58Met Ile Lys Ser Phe Asn Glu Ile Ile Met Lys Val
Lys Ser Lys Glu 1 5 10 15 Met Lys Lys Val Ala Val Ala Val Ala Gln
Asp Glu Pro Val Leu Glu 20 25 30 Ala Val Arg Asp Ala Lys Lys Asn
Gly Ile Ala Asp Ala Ile Leu Val 35 40 45 Gly Asp His Asp Glu Ile
Val Ser Ile Ala Leu Lys Ile Gly Met Asp 50 55 60 Val Asn Asp Phe
Glu Ile Val Asn Glu Pro Asn Val Lys Lys Ala Ala 65 70 75 80 Leu Lys
Ala Val Glu Leu Val Ser Thr Gly Lys Ala Asp Met Val Met 85 90 95
Lys Gly Leu Val Asn Thr Ala Thr Phe Leu Arg Ser Val Leu Asn Lys 100
105 110 Glu Val Gly Leu Arg Thr Gly Lys Thr Met Ser His Val Ala Val
Phe 115 120 125 Glu Thr Glu Lys Phe Asp Arg Leu Leu Phe Leu Thr Asp
Val Ala Phe 130 135 140 Asn Thr Tyr Pro Glu Leu Lys Glu Lys Ile Asp
Ile Val Asn Asn Ser 145 150 155 160 Val Lys Val Ala His Ala Ile Gly
Ile Glu Asn Pro Lys Val Ala Pro 165 170 175 Ile Cys Ala Val Glu Val
Ile Asn Pro Lys Met Pro Ser Thr Leu Asp 180 185 190 Ala Ala Met Leu
Ser Lys Met Ser Asp Arg Gly Gln Ile Lys Gly Cys 195 200 205 Val Val
Asp Gly Pro Leu Ala Leu Asp Ile Ala Leu Ser Glu Glu Ala 210 215 220
Ala His His Lys Gly Val Thr Gly Glu Val Ala Gly Lys Ala Asp Ile 225
230 235 240 Phe Leu Met Pro Asn Ile Glu Thr Gly Asn Val Met Tyr Lys
Thr Leu 245 250 255 Thr Tyr Thr Thr Asp Ser Lys Asn Gly Gly Ile Leu
Val Gly Thr Ser 260 265 270 Ala Pro Val Val Leu Thr Ser Arg Ala Asp
Ser His Glu Thr Lys Met 275 280 285 Asn Ser Ile Ala Leu Ala Ala Leu
Val Ala Gly Asn Lys 290 295 300 591068DNAClostridium acetobutylicum
59atgtatagat tactaataat caatcctggc tcgacctcaa ctaaaattgg tatttatgac
60gatgaaaaag agatatttga gaagacttta agacattcag ctgaagagat agaaaaatat
120aacactatat ttgatcaatt tcaattcaga aagaatgtaa ttttagatgc
gttaaaagaa 180gcaaacatag aagtaagttc tttaaatgct gtagttggaa
gaggcggact cttaaagcca 240atagtaagtg gaacttatgc agtaaatcaa
aaaatgcttg aagaccttaa agtaggagtt 300caaggtcagc atgcgtcaaa
tcttggtgga attattgcaa atgaaatagc aaaagaaata 360aatgttccag
catacatagt tgatccagtt gttgtggatg agcttgatga agtttcaaga
420atatcaggaa tggctgacat tccaagaaaa agtatattcc atgcattaaa
tcaaaaagca 480gttgctagaa gatatgcaaa agaagttgga aaaaaatacg
aagatcttaa tttaatcgta 540gtccacatgg gtggaggtac ttcagtaggt
actcataaag atggtagagt aatagaagtt 600aataatacac ttgatggaga
aggtccattc tcaccagaaa gaagtggtgg agttccaata 660ggagatcttg
taagattgtg cttcagcaac aaatatactt atgaagaagt aatgaaaaag
720ataaacggca aaggcggagt tgttagttac ttaaatacta tcgattttaa
ggctgtagtt 780gataaagctc ttgaaggaga taagaaatgt gcacttatat
atgaagcttt cacattccag 840gtagcaaaag agataggaaa atgttcaacc
gttttaaaag gaaatgtaga tgcaataatc 900ttaacaggcg gaattgcgta
caacgagcat gtatgtaatg ccatagagga tagagtaaaa 960ttcatagcac
ctgtagttag atatggtgga gaagatgaac ttcttgcact tgcagaaggt
1020ggacttagag ttttaagagg agaagaaaaa gctaaggaat acaaataa
106860355PRTClostridium acetobutylicum 60Met Tyr Arg Leu Leu Ile
Ile Asn Pro Gly Ser Thr Ser Thr Lys Ile 1 5 10 15 Gly Ile Tyr Asp
Asp Glu Lys Glu Ile Phe Glu Lys Thr Leu Arg His 20 25 30 Ser Ala
Glu Glu Ile Glu Lys Tyr Asn Thr Ile Phe Asp Gln Phe Gln 35 40 45
Phe Arg Lys Asn Val Ile Leu Asp Ala Leu Lys Glu Ala Asn Ile Glu 50
55 60 Val Ser Ser Leu Asn Ala Val Val Gly Arg Gly Gly Leu Leu Lys
Pro 65 70 75 80 Ile Val Ser Gly Thr Tyr Ala Val Asn Gln Lys Met Leu
Glu Asp Leu 85 90 95 Lys Val Gly Val Gln Gly Gln His Ala Ser Asn
Leu Gly Gly Ile Ile 100 105 110 Ala Asn Glu Ile Ala Lys Glu Ile Asn
Val Pro Ala Tyr Ile Val Asp 115 120 125 Pro Val Val Val Asp Glu Leu
Asp Glu Val Ser Arg Ile Ser Gly Met 130 135 140 Ala Asp Ile Pro Arg
Lys Ser Ile Phe His Ala Leu Asn Gln Lys Ala 145 150 155 160 Val Ala
Arg Arg Tyr Ala Lys Glu Val Gly Lys Lys Tyr Glu Asp Leu 165 170 175
Asn Leu Ile Val Val His Met Gly Gly Gly Thr Ser Val Gly Thr His 180
185 190 Lys Asp Gly Arg Val Ile Glu Val Asn Asn Thr Leu Asp Gly Glu
Gly 195 200 205 Pro Phe Ser Pro Glu Arg Ser Gly Gly Val Pro Ile Gly
Asp Leu Val 210 215 220 Arg Leu Cys Phe Ser Asn Lys Tyr Thr Tyr Glu
Glu Val Met Lys Lys 225 230 235 240 Ile Asn Gly Lys Gly Gly Val Val
Ser Tyr Leu Asn Thr Ile Asp Phe 245 250 255 Lys Ala Val Val Asp Lys
Ala Leu Glu Gly Asp Lys Lys Cys Ala Leu 260 265 270 Ile Tyr Glu Ala
Phe Thr Phe Gln Val Ala Lys Glu Ile Gly Lys Cys 275 280 285 Ser Thr
Val Leu Lys Gly Asn Val Asp Ala Ile Ile Leu Thr Gly Gly 290 295 300
Ile Ala Tyr Asn Glu His Val Cys Asn Ala Ile Glu Asp Arg Val Lys 305
310 315 320 Phe Ile Ala Pro Val Val Arg Tyr Gly Gly Glu Asp Glu Leu
Leu Ala 325 330 335 Leu Ala Glu Gly Gly Leu Arg Val Leu Arg Gly Glu
Glu Lys Ala Lys 340 345 350 Glu Tyr Lys 355 61906DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
61atgattaaga gttttaatga aattatcatg aaggtaaaga gcaaagaaat gaaaaaagtt
60gctgttgctg tagcacaaga cgagccagta cttgaagcag tacgcgatgc taagaaaaat
120ggtattgcag atgctattct tgttggcgac catgacgaaa tcgtgtcaat
cgcgcttaaa 180ataggcatgg atgtaaatga ttttgaaata gtaaacgagc
ctaacgttaa gaaagctgct 240ttaaaggcag tagagctggt atcaactgga
aaagctgata tggtaatgaa gggacttgta 300aatacagcaa ctttcttacg
ctctgtatta aacaaagaag ttggactgag aacaggaaaa 360actatgtctc
acgttgcagt atttgaaact gagaaatttg atcgtctgtt atttttaaca
420gatgttgctt tcaatactta tcctgaatta aaggaaaaaa ttgatatcgt
aaacaattca 480gttaaggttg cacatgcaat aggtattgaa aatccaaagg
ttgctccaat ttgtgcagtt 540gaggttataa accctaaaat gccatcaaca
cttgatgcag caatgctttc aaaaatgagt 600gacagaggac aaattaaagg
ttgtgtagtt gacggaccgt tagcacttga tatcgcttta 660tcagaagaag
cagcacatca taagggcgta acaggagaag ttgctggaaa agctgatatc
720ttcttaatgc caaacattga aacaggaaat gtaatgtata agactttaac
atatacaact 780gatagcaaaa atggcggaat cttagttgga acttctgcac
cagttgtttt aacttcacgc 840gctgacagcc atgaaacaaa aatgaactct
attgcacttg cagctttagt tgcaggcaat 900aaataa 90662906DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
62atgattaaga gttttaatga aattatcatg aaggtaaaga gcaaagaaat gaaaaaagtt
60gctgttgctg tagcacaaga cgagccagta cttgaagcag tacgcgatgc taagaaaaat
120ggtattgccg atgctattct ggttggcgac catgacgaaa tcgtgtctat
cgcgctgaaa 180ataggcatgg atgtaaatga ttttgaaatt gttaacgagc
ctaacgttaa gaaagctgcg 240ttaaaggcag tagagctggt atcaactgga
aaagctgata tggtaatgaa gggactggta 300aataccgcaa ctttcttacg
ctctgtatta aacaaagaag ttggtctgcg tacaggaaaa 360accatgtctc
acgttgcagt atttgaaact gagaaatttg atcgtctgtt atttttaaca
420gatgttgctt tcaatactta tcctgaatta aaggaaaaaa ttgatatcgt
taacaatagc
480gttaaggttg cacatgccat tggtattgaa aatccaaagg ttgctccaat
ttgtgcagtt 540gaggttatta acccgaaaat gccatcaaca cttgatgcag
caatgctttc aaaaatgagt 600gaccgcggac aaattaaagg ttgtgtagtt
gacggaccgc tggcacttga tatcgcttta 660tcagaagaag cagcacatca
taaaggcgta acaggagaag ttgctggaaa agctgatatc 720ttcttaatgc
caaacattga aacaggaaat gtaatgtata agacgttaac ctataccact
780gatagcaaaa atggcggcat cctggttgga acttctgcac cagttgtttt
aacttcacgc 840gctgacagcc atgaaacaaa aatgaactct attgcactgg
cagcgctggt tgcaggcaat 900aaataa 90663906DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
63atgattaaga gttttaatga aattatcatg aaggtaaaga gcaaagaaat gaaaaaagtt
60gctgttgctg ttgcacaaga cgagccggta ctggaagcgg tacgcgatgc taagaaaaat
120ggtattgccg atgctattct ggttggcgac catgacgaaa tcgtctctat
cgcgctgaaa 180attggcatgg atgttaatga ttttgaaatt gttaacgagc
ctaacgttaa gaaagctgcg 240ctgaaggcgg tagagctggt ttccaccgga
aaagctgata tggtaatgaa agggctggtg 300aataccgcaa ctttcttacg
cagcgtactg aacaaagaag ttggtctgcg taccggaaaa 360accatgagtc
acgttgcggt atttgaaact gagaaatttg atcgtctgct gtttctgacc
420gatgttgctt tcaatactta tcctgaatta aaagaaaaaa ttgatatcgt
taacaatagc 480gttaaggttg cgcatgccat tggtattgaa aatccaaagg
ttgctccaat ttgtgcagtt 540gaggttatta acccgaaaat gccatcaaca
cttgatgccg caatgcttag caaaatgagt 600gaccgcggac aaattaaagg
ttgtgtggtt gacggcccgc tggcactgga tatcgcgtta 660agcgaagaag
cggcacatca taaaggcgta accggcgaag ttgctggaaa agctgatatc
720ttcctgatgc caaacattga aacaggcaat gtaatgtata aaacgttaac
ctataccact 780gatagcaaaa atggcggcat cctggttgga acttctgcac
cagttgtttt aacctcacgc 840gctgacagcc atgaaaccaa aatgaacagc
attgcactgg cagcgctggt tgcaggcaat 900aaataa 90664906DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
64atgattaaaa gttttaacga aattatcatg aaagtgaaaa gcaaagagat gaaaaaagtg
60gcggttgcgg ttgcgcagga tgaaccggtg ctggaagcgg tgcgcgatgc caaaaaaaac
120ggtattgccg atgccattct ggtgggcgat cacgatgaaa ttgtctctat
tgcgctgaaa 180attggcatgg atgttaacga ttttgaaatt gttaatgaac
cgaacgtgaa aaaagcggcg 240ctgaaagcgg ttgaactggt ttccaccggt
aaagccgata tggtgatgaa agggctggtg 300aataccgcaa ccttcctgcg
cagcgtgctg aataaagaag tgggtctgcg taccggtaaa 360accatgagtc
atgttgcggt gtttgaaacc gaaaaatttg accgtctgct gtttctgacc
420gatgttgcgt ttaataccta tccggaactg aaagagaaaa ttgatatcgt
taataacagc 480gtgaaagtgg cgcatgccat tggtattgaa aacccgaaag
tggcgccgat ttgcgcggtt 540gaagtgatta acccgaaaat gccgtcaacg
ctggatgccg cgatgctcag caaaatgagc 600gatcgcggtc aaatcaaagg
ctgtgtggtt gatggcccgc tggcgctgga tatcgcgctt 660agcgaagaag
cggcgcatca taaaggcgtg accggcgaag tggccggtaa agccgatatt
720ttcctgatgc cgaatattga aaccggcaac gtgatgtata aaacgctgac
ctataccacc 780gacagcaaaa acggcggcat tctggtgggt accagcgcgc
cggtggtgct gacctcgcgc 840gccgacagcc atgaaaccaa aatgaacagc
attgcgctgg cggcgctggt ggccggtaat 900aaataa 906651068DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
65atgtatcgtt tactgattat caatcctggc tcgacctcaa ctaaaattgg tatttatgac
60gatgaaaaag agatatttga gaagacttta cgtcattcag ctgaagagat agaaaaatat
120aacactatat ttgatcaatt tcagttcaga aagaatgtaa ttctcgatgc
gttaaaagaa 180gcaaacattg aagtaagttc tttaaatgct gtagttggac
gcggcggact gttaaagcca 240atagtaagtg gaacttatgc agtaaatcaa
aaaatgcttg aagaccttaa agtaggcgtt 300caaggtcagc atgcgtcaaa
tcttggtgga attattgcaa atgaaatagc aaaagaaata 360aatgttccag
catacatcgt tgatccagtt gttgtggatg agcttgatga agtttcacgt
420atatcaggaa tggctgacat tccacgtaaa agtatattcc atgcattaaa
tcaaaaagca 480gttgctagac gctatgcaaa agaagttgga aaaaaatacg
aagatcttaa tttaatcgtg 540gtccacatgg gtggcggtac ttcagtaggt
actcataaag atggtagagt aattgaagtt 600aataatacac ttgatggaga
aggtccattc tcaccagaaa gaagtggtgg cgttccaata 660ggcgatcttg
tacgtttgtg cttcagcaac aaatatactt atgaagaagt aatgaaaaag
720ataaacggca aaggcggcgt tgttagttac ttaaatacta tcgattttaa
ggctgtagtt 780gataaagctc ttgaaggcga taagaaatgt gcacttatat
atgaagcttt cacattccag 840gtagcaaaag agataggaaa atgttcaacc
gttttaaaag gaaatgtaga tgcaataatc 900ttaacaggcg gaattgcgta
caacgagcat gtatgtaatg ccatagagga tagagtaaaa 960ttcattgcac
ctgtagttcg ttatggtgga gaagatgaac ttcttgcact tgcagaaggt
1020ggactgcgcg ttttacgcgg agaagaaaaa gctaaggaat acaaataa
1068661068DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 66atgtatcgtt tactgattat caatcctggc
tcgacctcaa ctaaaattgg tatttatgac 60gatgaaaaag agatatttga gaagacgtta
cgtcattcag ctgaagagat tgaaaaatat 120aacactatat ttgatcaatt
tcagttccgc aagaatgtga ttctcgatgc gttaaaagaa 180gcaaacattg
aagtcagttc tttaaatgct gtagttggac gcggcggact gttaaagcca
240attgtcagtg gaacttatgc agtaaatcaa aaaatgcttg aagaccttaa
agtgggcgtt 300caaggtcagc atgccagcaa tcttggtggc attattgcca
atgaaatcgc aaaagaaatc 360aatgttccag catacatcgt tgatccggtt
gttgtggatg agcttgatga agttagccgt 420ataagcggaa tggctgacat
tccacgtaaa agtatattcc atgcattaaa tcaaaaagca 480gttgctcgtc
gctatgcaaa agaagttggt aaaaaatacg aagatcttaa tttaatcgtg
540gtccacatgg gtggcggtac ttcagtaggt actcataaag atggtcgcgt
gattgaagtt 600aataatacac ttgatggcga aggtccattc tcaccagaac
gtagtggtgg cgttccaatt 660ggcgatctgg tacgtttgtg cttcagcaac
aaatatactt atgaagaagt gatgaaaaag 720ataaacggca aaggcggcgt
tgttagttac ctgaatacta tcgattttaa ggctgtagtt 780gataaagcgc
ttgaaggcga taagaaatgt gcactgattt atgaagcttt caccttccag
840gtagcaaaag agattggtaa atgttcaacc gttttaaaag gaaatgttga
tgccattatc 900ttaacaggcg gcattgctta caacgagcat gtatgtaatg
ccattgagga tcgcgtaaaa 960ttcattgcac ctgtagttcg ttatggtggc
gaagatgaac tgctggcact ggcagaaggt 1020ggactgcgcg ttttacgcgg
cgaagaaaaa gcgaaggaat acaaataa 1068671068DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
67atgtatcgtc tgctgattat caatcctggc tcgacctcaa ctaaaattgg tatttatgac
60gatgaaaaag agatatttga gaaaacgtta cgtcatagcg ctgaagagat tgaaaaatat
120aacactattt ttgatcaatt tcagttccgc aagaatgtga ttctcgatgc
gctgaaagaa 180gcaaacattg aagtcagttc gctgaatgcg gtagttggtc
gcggcggtct gctgaagcca 240attgtcagcg gcacttatgc ggtaaatcaa
aaaatgctgg aagacctgaa agtgggcgtt 300caggggcagc atgccagcaa
tcttggtggc attattgcca atgaaatcgc caaagaaatc 360aatgttccgg
catacatcgt tgatccggtt gttgtggatg agctggatga agttagccgt
420atcagcggaa tggctgacat tccacgtaaa agtattttcc atgcactgaa
tcaaaaagcg 480gttgcgcgtc gctatgcaaa agaagttggt aaaaaatacg
aagatcttaa tctgatcgtg 540gtgcatatgg gtggcggtac tagcgtcggt
actcataaag atggtcgcgt gattgaagtt 600aataatacac ttgatggcga
aggtccattc tcaccagaac gtagcggtgg cgttccaatt 660ggcgatctgg
tacgtttgtg cttcagcaac aaatatacct atgaagaagt gatgaaaaag
720ataaacggca aaggcggcgt tgttagttac ctgaatacta tcgattttaa
ggcggtagtt 780gataaagcgc tggaaggcga taagaaatgt gcactgattt
atgaagcgtt caccttccag 840gtggcaaaag agattggtaa atgttcaacc
gttctgaaag gcaatgttga tgccattatc 900ctgaccggcg gcattgctta
caacgagcat gtttgtaatg ccattgagga tcgcgtaaaa 960ttcattgcac
ctgtggttcg ttatggtggc gaagatgaac tgctggcact ggcagaaggt
1020ggtctgcgcg ttttacgcgg cgaagaaaaa gcgaaagaat acaaataa
1068681068DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 68atgtatcgtc tgctgattat caacccgggc
agcacctcaa ccaaaattgg tatttacgac 60gatgaaaaag agatttttga aaaaacgctg
cgtcacagcg cagaagagat tgaaaaatac 120aacaccattt tcgatcagtt
ccagttccgc aaaaacgtga ttctcgatgc gctgaaagaa 180gccaatattg
aagtctcctc gctgaatgcg gtggtcggtc gcggcggtct gctgaaaccg
240attgtcagcg gcacttatgc ggttaatcag aaaatgctgg aagatctgaa
agtgggcgtg 300caggggcagc atgccagcaa tctcggcggc attatcgcca
atgaaatcgc caaagagatc 360aacgtgccgg cttatatcgt cgatccggtg
gtggttgatg aactggatga agtcagccgt 420atcagcggca tggcggatat
tccgcgtaaa agcattttcc atgcgctgaa tcagaaagcg 480gttgcgcgtc
gctatgccaa agaagtgggt aaaaaatatg aagatctcaa tctgattgtg
540gtgcatatgg gcggcggcac cagcgtcggt acgcataaag atggtcgcgt
gattgaagtg 600aataacacgc tggatggcga agggccgttc tcgccggaac
gtagcggcgg cgtgccgatt 660ggcgatctgg tgcgtctgtg tttcagcaat
aaatacacct acgaagaagt gatgaaaaaa 720atcaacggca aaggcggcgt
ggttagctat ctgaatacca tcgattttaa agcggtggtt 780gataaagcgc
tggaaggcga taaaaaatgc gcgctgattt atgaagcgtt taccttccag
840gtggcgaaag agattggtaa atgttcaacc gtgctgaaag gcaacgttga
tgccattatt 900ctgaccggcg gcattgctta taacgaacat gtttgtaatg
ccattgaaga tcgcgtgaaa 960tttattgcgc cggtggtgcg ttacggcggc
gaagatgaac tgctggcgct ggcggaaggc 1020ggtctgcgcg tgctgcgcgg
cgaagaaaaa gcgaaagagt acaaataa 1068691407DNAClostridium
biejerinckii 69atgaataaag acacactaat acctacaact aaagatttaa
aagtaaaaac aaatggtgaa 60aacattaatt taaagaacta caaggataat tcttcatgtt
tcggagtatt cgaaaatgtt 120gaaaatgcta taagcagcgc tgtacacgca
caaaagatat tatcccttca ttatacaaaa 180gagcaaagag aaaaaatcat
aactgagata agaaaggccg cattacaaaa taaagaggtc 240ttggctacaa
tgattctaga agaaacacat atgggaagat atgaggataa aatattaaaa
300catgaattgg tagctaaata tactcctggt acagaagatt taactactac
tgcttggtca 360ggtgataatg gtcttacagt tgtagaaatg tctccatatg
gtgttatagg tgcaataact 420ccttctacga atccaactga aactgtaata
tgtaatagca taggcatgat agctgctgga 480aatgctgtag tatttaacgg
acacccatgc gctaaaaaat gtgttgcctt tgctgttgaa 540atgataaata
aggcaattat ttcatgtggc ggtcctgaaa atctagtaac aactataaaa
600aatccaacta tggagtctct agatgcaatt attaagcatc cttcaataaa
acttctttgc 660ggaactgggg gtccaggaat ggtaaaaacc ctcttaaatt
ctggtaagaa agctataggt 720gctggtgctg gaaatccacc agttattgta
gatgatactg ctgatataga aaaggctggt 780aggagcatca ttgaaggctg
ttcttttgat aataatttac cttgtattgc agaaaaagaa 840gtatttgttt
ttgagaatgt tgcagatgat ttaatatcta acatgctaaa aaataatgct
900gtaattataa atgaagatca agtatcaaaa ttaatagatt tagtattaca
aaaaaataat 960gaaactcaag aatactttat aaacaaaaaa tgggtaggaa
aagatgcaaa attattctta 1020gatgaaatag atgttgagtc tccttcaaat
gttaaatgca taatctgcga agtaaatgca 1080aatcatccat ttgttatgac
agaactcatg atgccaatat tgccaattgt aagagttaaa 1140gatatagatg
aagctattaa atatgcaaag atagcagaac aaaatagaaa acatagtgcc
1200tatatttatt ctaaaaatat agacaaccta aatagatttg aaagagaaat
agatactact 1260atttttgtaa agaatgctaa atcttttgct ggtgttggtt
atgaagcaga aggatttaca 1320actttcacta ttgctggatc tactggtgag
ggaataacct ctgcaaggaa ttttacaaga 1380caaagaagat gtgtacttgc cggctaa
140770468PRTClostridium biejerinckii 70Met Asn Lys Asp Thr Leu Ile
Pro Thr Thr Lys Asp Leu Lys Val Lys 1 5 10 15 Thr Asn Gly Glu Asn
Ile Asn Leu Lys Asn Tyr Lys Asp Asn Ser Ser 20 25 30 Cys Phe Gly
Val Phe Glu Asn Val Glu Asn Ala Ile Ser Ser Ala Val 35 40 45 His
Ala Gln Lys Ile Leu Ser Leu His Tyr Thr Lys Glu Gln Arg Glu 50 55
60 Lys Ile Ile Thr Glu Ile Arg Lys Ala Ala Leu Gln Asn Lys Glu Val
65 70 75 80 Leu Ala Thr Met Ile Leu Glu Glu Thr His Met Gly Arg Tyr
Glu Asp 85 90 95 Lys Ile Leu Lys His Glu Leu Val Ala Lys Tyr Thr
Pro Gly Thr Glu 100 105 110 Asp Leu Thr Thr Thr Ala Trp Ser Gly Asp
Asn Gly Leu Thr Val Val 115 120 125 Glu Met Ser Pro Tyr Gly Val Ile
Gly Ala Ile Thr Pro Ser Thr Asn 130 135 140 Pro Thr Glu Thr Val Ile
Cys Asn Ser Ile Gly Met Ile Ala Ala Gly 145 150 155 160 Asn Ala Val
Val Phe Asn Gly His Pro Cys Ala Lys Lys Cys Val Ala 165 170 175 Phe
Ala Val Glu Met Ile Asn Lys Ala Ile Ile Ser Cys Gly Gly Pro 180 185
190 Glu Asn Leu Val Thr Thr Ile Lys Asn Pro Thr Met Glu Ser Leu Asp
195 200 205 Ala Ile Ile Lys His Pro Ser Ile Lys Leu Leu Cys Gly Thr
Gly Gly 210 215 220 Pro Gly Met Val Lys Thr Leu Leu Asn Ser Gly Lys
Lys Ala Ile Gly 225 230 235 240 Ala Gly Ala Gly Asn Pro Pro Val Ile
Val Asp Asp Thr Ala Asp Ile 245 250 255 Glu Lys Ala Gly Arg Ser Ile
Ile Glu Gly Cys Ser Phe Asp Asn Asn 260 265 270 Leu Pro Cys Ile Ala
Glu Lys Glu Val Phe Val Phe Glu Asn Val Ala 275 280 285 Asp Asp Leu
Ile Ser Asn Met Leu Lys Asn Asn Ala Val Ile Ile Asn 290 295 300 Glu
Asp Gln Val Ser Lys Leu Ile Asp Leu Val Leu Gln Lys Asn Asn 305 310
315 320 Glu Thr Gln Glu Tyr Phe Ile Asn Lys Lys Trp Val Gly Lys Asp
Ala 325 330 335 Lys Leu Phe Leu Asp Glu Ile Asp Val Glu Ser Pro Ser
Asn Val Lys 340 345 350 Cys Ile Ile Cys Glu Val Asn Ala Asn His Pro
Phe Val Met Thr Glu 355 360 365 Leu Met Met Pro Ile Leu Pro Ile Val
Arg Val Lys Asp Ile Asp Glu 370 375 380 Ala Ile Lys Tyr Ala Lys Ile
Ala Glu Gln Asn Arg Lys His Ser Ala 385 390 395 400 Tyr Ile Tyr Ser
Lys Asn Ile Asp Asn Leu Asn Arg Phe Glu Arg Glu 405 410 415 Ile Asp
Thr Thr Ile Phe Val Lys Asn Ala Lys Ser Phe Ala Gly Val 420 425 430
Gly Tyr Glu Ala Glu Gly Phe Thr Thr Phe Thr Ile Ala Gly Ser Thr 435
440 445 Gly Glu Gly Ile Thr Ser Ala Arg Asn Phe Thr Arg Gln Arg Arg
Cys 450 455 460 Val Leu Ala Gly 465 711407DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
71atgaataaag acacactaat acctacaact aaagatttaa aagtaaaaac aaatggtgaa
60aacattaatt taaagaacta caaggataat tcttcatgtt tcggcgtatt cgaaaatgtt
120gaaaatgcta taagcagcgc tgtacacgca caaaagatat tatcccttca
ttatacaaaa 180gagcaacgtg aaaaaatcat aactgagata agaaaggccg
cattacaaaa taaagaggtc 240ttggctacaa tgattctgga agaaacacat
atgggacgtt atgaggataa aatattaaaa 300catgaattgg tagctaaata
tactcctggt acagaagatt taactactac tgcctggtca 360ggtgataatg
gtctgacagt tgtagaaatg tctccatatg gtgttattgg tgcaataact
420ccttctacga atccaactga aactgtaata tgtaatagca taggcatgat
tgctgctgga 480aatgctgtag tatttaacgg acacccatgc gctaaaaaat
gtgttgcctt tgctgttgaa 540atgataaata aggcaattat ttcatgtggc
ggtcctgaaa atctggtaac aactataaaa 600aatccaacca tggagtctct
ggatgcaatt attaagcatc cttcaataaa acttctttgc 660ggaactgggg
gtccaggaat ggtaaaaacc ctgttaaatt ctggtaagaa agctataggt
720gctggtgctg gaaatccacc agttattgtc gatgatactg ctgatataga
aaaggctggt 780cgtagcatca ttgaaggctg ttcttttgat aataatttac
cttgtattgc agaaaaagaa 840gtatttgttt ttgagaatgt tgcagatgat
ttaatatcta acatgctaaa aaataatgct 900gtaattataa atgaagatca
agtatcaaaa ttaatcgatt tagtattaca aaaaaataat 960gaaactcaag
aatactttat aaacaaaaaa tgggtaggaa aagatgcaaa attattcctc
1020gatgaaatag atgttgagtc tccttcaaat gttaaatgca taatctgcga
agtaaatgca 1080aatcatccat ttgttatgac agaactgatg atgccaatat
tgccaattgt acgcgttaaa 1140gatatcgatg aagctattaa atatgcaaag
atagcagaac aaaatagaaa acatagtgcc 1200tatatttatt ctaaaaatat
cgacaacctg aatcgctttg aacgtgaaat agatactact 1260atttttgtaa
agaatgctaa atcttttgct ggtgttggtt atgaagcaga aggatttaca
1320actttcacta ttgctggatc tactggtgag ggaataacct ctgcacgtaa
ttttacacgc 1380caacgtcgct gtgtacttgc cggctaa
1407721407DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 72atgaataaag acacactgat ccctacaact
aaagatttaa aagtaaaaac aaatggtgaa 60aacattaatt taaagaacta caaagataat
agcagttgtt tcggcgtatt cgaaaatgtt 120gaaaatgcta tcagcagcgc
tgtacacgca caaaagatat tatcgctgca ttatacaaaa 180gagcaacgtg
aaaaaatcat cactgagata cgtaaggccg cattacaaaa taaagaggtg
240ctggctacaa tgattctgga agaaacacat atgggacgtt atgaggataa
aatattaaaa 300catgaactgg tagctaaata tactcctggt acagaagatt
taactactac tgcctggagc 360ggtgataatg gtctgacagt tgtagaaatg
tctccatatg gtgttattgg tgcaataact 420ccttctacca atccaactga
aactgtaatt tgtaatagca ttggcatgat tgctgctgga 480aatgctgtag
tatttaacgg acacccatgc gctaaaaaat gtgttgcctt tgctgttgaa
540atgatcaata aggcaattat tagctgtggc ggtccggaaa atctggtaac
aactataaaa 600aatccaacca tggagtctct ggatgccatt attaagcatc
cttcaataaa actgctttgc 660ggaactggcg gtccaggaat ggtaaaaacc
ctgttaaatt ctggtaagaa agctattggt 720gctggtgctg gaaatccacc
agttattgtc gatgatactg ctgatattga aaaggctggt 780cgtagcatca
ttgaaggctg ttcttttgat aataatttac cttgtattgc agaaaaagaa
840gtatttgttt ttgagaatgt tgcagatgat ttaatatcta acatgctgaa
aaataatgct 900gtaattatca atgaagatca ggtatcaaaa ttaatcgatt
tagtattaca aaaaaataat 960gaaactcaag aatactttat caacaaaaaa
tgggtaggta aagatgcaaa attattcctc 1020gatgaaatcg atgttgagtc
tccttcaaat gttaaatgca ttatctgcga agtgaatgcc 1080aatcatccat
ttgttatgac agaactgatg atgccaatat tgccaattgt gcgcgttaaa
1140gatatcgatg aagctattaa atatgcaaag attgcagaac aaaatagaaa
acatagtgcc 1200tatatttata gcaaaaatat cgacaacctg aatcgctttg
aacgtgaaat cgatactact 1260atttttgtaa agaatgctaa atcttttgct
ggtgttggtt atgaagcaga aggatttacc 1320actttcacta ttgctggatc
tactggtgag ggcataacct ctgcacgtaa ttttacccgc 1380caacgtcgct
gtgtactggc cggctaa 1407731407DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 73atgaataaag
acacgctgat cccgacaact aaagatctga aagtaaaaac caatggtgaa 60aacattaatc
tgaagaacta caaagataat agcagttgtt tcggcgtatt cgaaaatgtt
120gaaaatgcta tcagcagcgc ggtacacgca caaaagatac tctcgctgca
ttataccaaa 180gagcaacgtg aaaaaatcat cactgagatc cgtaaggccg
cattacaaaa taaagaggtg 240ctggcaacaa tgattctgga agaaacacat
atgggacgtt atgaggataa aatactgaaa 300catgaactgg tggcgaaata
tacgcctggt actgaagatt taaccaccac tgcctggagc 360ggtgataatg
gtctgaccgt tgtggaaatg tcgccttatg gtgttattgg tgcaattacg
420ccttcaacca atccaactga aacggtaatt tgtaatagca ttggcatgat
tgctgctgga 480aatgcggtag tatttaacgg tcacccctgc gctaaaaaat
gtgttgcctt tgctgttgaa 540atgatcaata aagcgattat tagctgtggc
ggtccggaaa atctggtaac cactataaaa 600aatccaacca tggagtcgct
ggatgccatt attaagcatc cttcaatcaa actgctgtgc 660ggcactggcg
gtccaggaat ggtgaaaacc ctgctgaata gcggtaagaa agcgattggt
720gctggtgctg gaaatccacc agttattgtc gatgatactg ctgatattga
aaaagcgggt 780cgtagcatca ttgaaggctg ttcttttgat aataatttac
cttgtattgc agaaaaagaa 840gtatttgttt ttgagaatgt tgccgatgat
ctgatctcta acatgctgaa aaataatgcg 900gtgattatca atgaagatca
ggttagcaaa ctgatcgatc tggtattaca aaaaaataat 960gaaactcaag
aatactttat caacaaaaaa tgggtaggta aagatgcaaa actgttcctc
1020gatgaaatcg atgttgagtc gccttcaaat gttaaatgca ttatctgcga
agtgaatgcc 1080aatcatccat ttgtgatgac cgaactgatg atgccaattt
tgccgattgt gcgcgttaaa 1140gatatcgatg aagcgattaa atatgcaaag
attgcagaac aaaatcgtaa acatagtgcc 1200tatatttata gcaaaaatat
cgacaacctg aatcgctttg aacgtgaaat cgataccact 1260atttttgtga
agaatgctaa atcttttgct ggtgttggtt atgaagcaga aggttttacc
1320actttcacta ttgctggaag caccggtgaa ggcattacct ctgcacgtaa
ttttacccgc 1380caacgtcgct gtgtactggc cggctaa
1407741407DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 74atgaataaag atacgctgat cccgaccacc
aaagatctga aagtgaaaac caacggcgaa 60aatatcaacc tgaaaaacta taaagataac
agcagttgct ttggcgtgtt tgaaaacgtt 120gaaaacgcca tctccagcgc
ggtgcatgcg caaaaaattc tctcgctgca ttacaccaaa 180gagcagcgtg
aaaaaattat caccgaaatc cgtaaagcgg cgctgcaaaa caaagaagtg
240ctggcaacca tgatcctgga agaaacgcat atggggcgtt atgaagataa
aattctgaaa 300catgaactgg tggcgaaata cacgccgggc actgaagatc
tgaccaccac cgcctggagc 360ggcgataacg gcctgaccgt ggtggagatg
tcgccttatg gcgtgattgg cgcgattacg 420ccgtcaacca acccgaccga
aacggtgatt tgtaacagca ttggcatgat tgccgcgggt 480aatgcggtgg
tgtttaacgg tcatccctgc gcgaaaaaat gtgtggcgtt tgccgttgag
540atgatcaaca aagcgattat cagctgcggc ggcccggaaa atctggtgac
caccatcaaa 600aatccgacca tggaatcgct ggatgccatt atcaaacatc
cttccatcaa actgctgtgc 660ggcaccggcg gcccgggcat ggtgaaaacg
ctgctgaaca gcggtaaaaa agcgattggc 720gcgggcgcgg gtaacccgcc
ggtgattgtc gatgacaccg ccgatattga aaaagcgggg 780cgtagcatta
ttgaaggctg ttcttttgat aacaacctgc cctgcattgc cgaaaaagaa
840gtgtttgtct ttgaaaacgt cgccgatgat ctgatcagca atatgctgaa
aaacaacgcg 900gtgattatca atgaagatca ggttagcaaa ctgatcgatc
tggtgctgca aaaaaacaac 960gaaacgcagg aatattttat caacaaaaaa
tgggttggta aagatgccaa actgtttctc 1020gatgaaatcg atgttgaatc
gccgtctaac gtgaaatgta ttatctgcga agtgaacgcc 1080aaccatccgt
ttgtgatgac cgaactgatg atgccgattc tgccgattgt gcgcgtgaaa
1140gatatcgatg aagcgattaa atatgccaaa attgccgaac aaaaccgtaa
acacagcgcc 1200tatatttaca gcaaaaatat cgataacctg aaccgctttg
aacgtgaaat cgataccacc 1260atttttgtga aaaatgccaa aagttttgcc
ggcgttggtt atgaagcgga aggttttacc 1320acctttacca ttgccggtag
caccggcgaa ggcattacca gcgcccgtaa ttttacccgc 1380cagcgtcgct
gcgtgctggc gggctaa 1407751023DNAGeobacillus thermoglucosidasius
75atgaaagctg cagtagtaga gcaatttaag gaaccattaa aaattaaaga agtggaaaag
60ccatctattt catatggcga agtattagtc cgcattaaag catgcggtgt atgccatacg
120gacttgcacg ccgctcatgg cgattggcca gtaaaaccaa aacttccttt
aatccctggc 180catgaaggag tcggaattgt tgaagaagtc ggtccggggg
taacccattt aaaagtggga 240gaccgcgttg gaattccttg gttatattct
gcgtgcggcc attgcgaata ttgtttaagc 300ggacaagaag cattatgtga
acatcaacaa aacgccggct actcagtcga cgggggttat 360gcagaatatt
gcagagctgc gccagattat gtggtgaaaa ttcctgacaa cttatcgttt
420gaagaagctg ctcctatttt ctgcgccgga gttactactt ataaagcgtt
aaaagtcaca 480ggtacaaaac cgggagaatg ggtagcgatc tatggcatcg
gcggccttgg acatgttgcc 540gtccagtatg cgaaagcgat ggggcttcat
gttgttgcag tggatatcgg cgatgagaaa 600ctggaacttg caaaagagct
tggcgccgat cttgttgtaa atcctgcaaa agaaaatgcg 660gcccaattta
tgaaagagaa agtcggcgga gtacacgcgg ctgttgtgac agctgtatct
720aaacctgctt ttcaatctgc gtacaattct atccgcagag gcggcacgtg
cgtgcttgtc 780ggattaccgc cggaagaaat gcctattcca atctttgata
cggtattaaa cggaattaaa 840attatcggtt ccattgtcgg cacgcggaaa
gacttgcaag aagcgcttca gttcgctgca 900gaaggtaaag taaaaaccat
tattgaagtg caacctcttg aaaaaattaa cgaagtattt 960gacagaatgc
taaaaggaga aattaacgga cgggttgttt taacgttaga aaataataat 1020taa
102376340PRTGeobacillus thermoglucosidasius 76Met Lys Ala Ala Val
Val Glu Gln Phe Lys Glu Pro Leu Lys Ile Lys 1 5 10 15 Glu Val Glu
Lys Pro Ser Ile Ser Tyr Gly Glu Val Leu Val Arg Ile 20 25 30 Lys
Ala Cys Gly Val Cys His Thr Asp Leu His Ala Ala His Gly Asp 35 40
45 Trp Pro Val Lys Pro Lys Leu Pro Leu Ile Pro Gly His Glu Gly Val
50 55 60 Gly Ile Val Glu Glu Val Gly Pro Gly Val Thr His Leu Lys
Val Gly 65 70 75 80 Asp Arg Val Gly Ile Pro Trp Leu Tyr Ser Ala Cys
Gly His Cys Glu 85 90 95 Tyr Cys Leu Ser Gly Gln Glu Ala Leu Cys
Glu His Gln Gln Asn Ala 100 105 110 Gly Tyr Ser Val Asp Gly Gly Tyr
Ala Glu Tyr Cys Arg Ala Ala Pro 115 120 125 Asp Tyr Val Val Lys Ile
Pro Asp Asn Leu Ser Phe Glu Glu Ala Ala 130 135 140 Pro Ile Phe Cys
Ala Gly Val Thr Thr Tyr Lys Ala Leu Lys Val Thr 145 150 155 160 Gly
Thr Lys Pro Gly Glu Trp Val Ala Ile Tyr Gly Ile Gly Gly Leu 165 170
175 Gly His Val Ala Val Gln Tyr Ala Lys Ala Met Gly Leu His Val Val
180 185 190 Ala Val Asp Ile Gly Asp Glu Lys Leu Glu Leu Ala Lys Glu
Leu Gly 195 200 205 Ala Asp Leu Val Val Asn Pro Ala Lys Glu Asn Ala
Ala Gln Phe Met 210 215 220 Lys Glu Lys Val Gly Gly Val His Ala Ala
Val Val Thr Ala Val Ser 225 230 235 240 Lys Pro Ala Phe Gln Ser Ala
Tyr Asn Ser Ile Arg Arg Gly Gly Thr 245 250 255 Cys Val Leu Val Gly
Leu Pro Pro Glu Glu Met Pro Ile Pro Ile Phe 260 265 270 Asp Thr Val
Leu Asn Gly Ile Lys Ile Ile Gly Ser Ile Val Gly Thr 275 280 285 Arg
Lys Asp Leu Gln Glu Ala Leu Gln Phe Ala Ala Glu Gly Lys Val 290 295
300 Lys Thr Ile Ile Glu Val Gln Pro Leu Glu Lys Ile Asn Glu Val Phe
305 310 315 320 Asp Arg Met Leu Lys Gly Glu Ile Asn Gly Arg Val Val
Leu Thr Leu 325 330 335 Glu Asn Asn Asn 340 774090DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
77atggctatcg aaatcaaagt accggacatc ggggctgatg aagttgaaat caccgagatc
60ctggtcaaag tgggcgacaa agttgaagcc gaacagtcgc tgatcaccgt agaaggcgac
120aaagcctcta tggaagttcc gtctccgcag gcgggtatcg ttaaagagat
caaagtctct 180gttggcgata aaacccagac cggcgcactg attatgattt
tcgattccgc cgacggtgca 240gcagacgctg cacctgctca ggcagaagag
aagaaagaag cagctccggc agcagcacca 300gcggctgcgg cggcaaaaga
cgttaacgtt ccggatatcg gcagcgacga agttgaagtg 360accgaaatcc
tggtgaaagt tggcgataaa gttgaagctg aacagtcgct gatcaccgta
420gaaggcgaca aggcttctat ggaagttccg gctccgtttg ctggcaccgt
gaaagagatc 480aaagtgaacg tgggtgacaa agtgtctacc ggctcgctga
ttatggtctt cgaagtcgcg 540ggtgaagcag gcgcggcagc tccggccgct
aaacaggaag cagctccggc agcggcccct 600gcaccagcgg ctggcgtgaa
agaagttaac gttccggata tcggcggtga cgaagttgaa 660gtgactgaag
tgatggtgaa agtgggcgac aaagttgccg ctgaacagtc actgatcacc
720gtagaaggcg acaaagcttc tatggaagtt ccggcgccgt ttgcaggcgt
cgtgaaggaa 780ctgaaagtca acgttggcga taaagtgaaa actggctcgc
tgattatgat cttcgaagtt 840gaaggcgcag cgcctgcggc agctcctgcg
aaacaggaag cggcagcgcc ggcaccggca 900gcaaaagctg aagccccggc
agcagcacca gctgcgaaag cggaaggcaa atctgaattt 960gctgaaaacg
acgcttatgt tcacgcgact ccgctgatcc gccgtctggc acgcgagttt
1020ggtgttaacc ttgcgaaagt gaagggcact ggccgtaaag gtcgtatcct
gcgcgaagac 1080gttcaggctt acgtgaaaga agctatcaaa cgtgcagaag
cagctccggc agcgactggc 1140ggtggtatcc ctggcatgct gccgtggccg
aaggtggact tcagcaagtt tggtgaaatc 1200gaagaagtgg aactgggccg
catccagaaa atctctggtg cgaacctgag ccgtaactgg 1260gtaatgatcc
cgcatgttac tcacttcgac aaaaccgata tcaccgagtt ggaagcgttc
1320cgtaaacagc agaacgaaga agcggcgaaa cgtaagctgg atgtgaagat
caccccggtt 1380gtcttcatca tgaaagccgt tgctgcagct cttgagcaga
tgcctcgctt caatagttcg 1440ctgtcggaag acggtcagcg tctgaccctg
aagaaataca tcaacatcgg tgtggcggtg 1500gataccccga acggtctggt
tgttccggta ttcaaagacg tcaacaagaa aggcatcatc 1560gagctgtctc
gcgagctgat gactatttct aagaaagcgc gtgacggtaa gctgactgcg
1620ggcgaaatgc agggcggttg cttcaccatc tccagcatcg gcggcctggg
tactacccac 1680ttcgcgccga ttgtgaacgc gccggaagtg gctatcctcg
gcgtttccaa gtccgcgatg 1740gagccggtgt ggaatggtaa agagttcgtg
ccgcgtctga tgctgccgat ttctctctcc 1800ttcgaccacc gcgtgatcga
cggtgctgat ggtgcccgtt tcattaccat cattaacaac 1860acgctgtctg
acattcgccg tctggtgatg taagtaaaag agccggccca acggccggct
1920tttttctggt aatctcatga atgtattgag gttattagcg aatagacaaa
tcggttgccg 1980tttgttgttt aaaaattgtt aacaattttg taaaataccg
acggatagaa cgacccggtg 2040gtggttaggg tattacttca cataccctat
ggatttctgg gtgcagcaag gtagcaagcg 2100ccagaatccc caggagctta
cataagtaag tgactggggt gagggcgtga agctaacgcc 2160gctgcggcct
gaaagacgac gggtatgacc gccggagata aatatataga ggtcatgatg
2220agtactgaaa tcaaaactca ggtcgtggta cttggggcag gccccgcagg
ttactccgct 2280gccttccgtt gcgctgattt aggtctggaa accgtaatcg
tagaacgtta caacaccctt 2340ggcggtgttt gtctgaacgt gggttgtatc
ccttctaaag cgctgctgca cgtggcaaaa 2400gttatcgaag aagcgaaagc
gctggccgaa cacggcatcg ttttcggcga accgaaaact 2460gacattgaca
agatccgcac ctggaaagaa aaagtcatca ctcagctgac cggtggtctg
2520gctggcatgg ccaaaggtcg taaagtgaag gtggttaacg gtctgggtaa
atttaccggc 2580gctaacaccc tggaagtgga aggcgaaaac ggcaaaaccg
tgatcaactt cgacaacgcc 2640atcatcgcgg cgggttcccg tccgattcag
ctgccgttta tcccgcatga agatccgcgc 2700gtatgggact ccaccgacgc
gctggaactg aaatctgtac cgaaacgcat gctggtgatg 2760ggcggcggta
tcatcggtct ggaaatgggt accgtatacc atgcgctggg ttcagagatt
2820gacgtggtgg aaatgttcga ccaggttatc ccggctgccg acaaagacgt
ggtgaaagtc 2880ttcaccaaac gcatcagcaa gaaatttaac ctgatgctgg
aagccaaagt gactgccgtt 2940gaagcgaaag aagacggtat ttacgtttcc
atggaaggta aaaaagcacc ggcggaagcg 3000cagcgttacg acgcagtgct
ggtcgctatc ggccgcgtac cgaatggtaa aaacctcgat 3060gcaggtaaag
ctggcgtgga agttgacgat cgcggcttca tccgcgttga caaacaaatg
3120cgcaccaacg tgccgcacat ctttgctatc ggcgatatcg tcggtcagcc
gatgctggcg 3180cacaaaggtg tccatgaagg ccacgttgcc gcagaagtta
tctccggtct gaaacactac 3240ttcgatccga aagtgatccc atccatcgcc
tacactaaac cagaagtggc atgggtcggt 3300ctgaccgaga aagaagcgaa
agagaaaggc atcagctacg aaaccgccac cttcccgtgg 3360gctgcttccg
gccgtgctat cgcttctgac tgcgcagatg gtatgaccaa actgatcttc
3420gacaaagaga cccaccgtgt tatcggcggc gcgattgtcg gcaccaacgg
cggcgagctg 3480ctgggtgaga tcggcctggc tatcgagatg ggctgtgacg
ctgaagacat cgccctgacc 3540atccacgctc acccgactct gcacgagtcc
gttggcctgg cggcggaagt gttcgaaggc 3600agcatcaccg acctgccaaa
cgccaaagcg aagaaaaagt aactttttct ttcaggaaaa 3660aagcataagc
ggctccggga gccgcttttt ttatgcctga tgtttagaac tatgtcactg
3720ttcataaacc gctacacctc atacatactt taagggcgaa ttctgcagat
atccatcaca 3780ctggcggccg ctcgagcatg catctagcac atccggcaat
taaaaaagcg gctaaccacg 3840ccgctttttt tacgtctgca atttaccttt
ccagtcttct tgctccacgt tcagagagac 3900gttcgcatac tgctgaccgt
tgctcgttat tcagcctgac agtatggtta ctgtcgttta 3960gacgttgtgg
gcggctctcc tgaactttct cccgaaaaac ctgacgttgt tcaggtgatg
4020ccgattgaac acgctggcgg gcgttatcac gttgctgttg attcagtggg
cgctgctgta 4080ctttttcctt 409078475PRTEscherichia coli 78Met Met
Ser Thr Glu Ile Lys Thr Gln Val Val Val Leu Gly Ala Gly 1 5 10 15
Pro Ala Gly Tyr Ser Ala Ala Phe Arg Cys Ala Asp Leu Gly Leu Glu 20
25 30 Thr Val Ile Val Glu Arg Tyr Asn Thr Leu Gly Gly Val Cys Leu
Asn 35 40 45 Val Gly Cys Ile Pro Ser Lys Ala Leu Leu His Val Ala
Lys Val Ile 50 55 60 Glu Glu Ala Lys Ala Leu Ala Glu His Gly Ile
Val Phe Gly Glu Pro 65 70 75 80 Lys Thr Asp Ile Asp Lys Ile Arg Thr
Trp Lys Glu Lys Val Ile Asn 85 90 95 Gln Leu Thr Gly Gly Leu Ala
Gly Met Ala Lys Gly Arg Lys Val Lys 100 105 110 Val Val Asn Gly Leu
Gly Lys Phe Thr Gly Ala Asn Thr Leu Glu Val 115 120 125 Glu Gly Glu
Asn Gly Lys Thr Val Ile Asn Phe Asp Asn Ala Ile Ile 130 135 140 Ala
Ala Gly Ser Arg Pro Ile Gln Leu Pro Phe Ile Pro His Glu Asp 145 150
155 160 Pro Arg Ile Trp Asp Ser Thr Asp Ala Leu Glu Leu Lys Glu Val
Pro 165 170 175 Glu Arg Leu Leu Val Met Gly Gly Gly Ile Ile Gly Leu
Glu Met Gly 180 185 190 Thr Val Tyr His Ala Leu Gly Ser Gln Ile Asp
Val Val Glu Met Phe 195 200 205 Asp Gln Val Ile Pro Ala Ala Asp Lys
Asp Ile Val Lys Val Phe Thr 210 215 220 Lys Arg Ile Ser Lys Lys Phe
Asn Leu Met Leu Glu Thr Lys Val Thr 225 230 235 240 Ala Val Glu Ala
Lys Glu Asp Gly Ile Tyr Val Thr Met Glu Gly Lys 245 250 255 Lys Ala
Pro Ala Glu Pro Gln Arg Tyr Asp Ala Val Leu Val Ala Ile 260 265 270
Gly Arg Val Pro Asn Gly Lys Asn Leu Asp Ala Gly Lys Ala Gly Val 275
280 285 Glu Val Asp Asp Arg Gly Phe Ile Arg Val Asp Lys Gln Leu Arg
Thr 290 295 300 Asn Val Pro His Ile Phe Ala Ile Gly Asp Ile Val Gly
Gln Pro Met 305 310 315 320 Leu Ala His Lys Gly Val His Glu Gly His
Val Ala Ala Glu Val Ile 325 330 335 Ala Gly Lys Lys His Tyr Phe Asp
Pro Lys Val Ile Pro Ser Ile Ala 340 345 350 Tyr Thr Glu Pro Glu Val
Ala Trp Val Gly Leu Thr Glu Lys Glu Ala 355 360 365 Lys Glu Lys Gly
Ile Ser Tyr Glu Thr Ala Thr Phe Pro Trp Ala Ala 370 375 380 Ser Gly
Arg Ala Ile Ala Ser Asp Cys Ala Asp Gly Met Thr Lys Leu 385 390 395
400 Ile Phe Asp Lys Glu Ser His Arg Val Ile Gly Gly Ala Ile Val Gly
405 410 415 Thr Asn Gly Gly Glu Leu Leu Gly Glu Ile Gly Leu Ala Ile
Glu Met 420 425 430 Gly Cys Asp Ala Glu Asp Ile Ala Leu Thr Ile His
Ala His Pro Thr 435 440 445 Leu His Glu Ser Val Gly Leu Ala Ala Glu
Val Phe Glu Gly Ser Ile 450 455 460 Thr Asp Leu Pro Asn Pro Lys Ala
Lys Lys Lys 465 470 475 79475PRTKlebsiella pneumoniae 79Met Met Ser
Thr Glu Ile Lys Thr Gln Val Val Val Leu Gly Ala Gly 1 5 10 15 Pro
Ala Gly Tyr Ser Ala Ala Phe Arg Cys Ala Asp Leu Gly Leu Glu 20 25
30 Thr Val Ile Val Glu Arg Tyr Ser Thr Leu Gly Gly Val Cys Leu Asn
35 40 45 Val Gly Cys Ile Pro Ser Lys Ala Leu Leu His Val Ala Lys
Val Ile 50 55 60 Glu Glu Ala Lys Ala Leu Ala Glu His Gly Ile Val
Phe Gly Glu Pro 65 70 75 80 Lys Thr Asp Ile Asp Lys Ile Arg Thr Trp
Lys Glu Lys Val Ile Thr 85 90 95 Gln Leu Thr Gly Gly Leu Ala Gly
Met Ala Lys Gly Arg Lys Val Lys 100 105 110 Val Val Asn Gly Leu Gly
Lys Phe Thr Gly Ala Asn Thr Leu Glu Val 115 120 125 Glu Gly Glu Asn
Gly Lys Thr Val Ile Asn Phe Asp Asn Ala Ile Ile 130 135 140 Ala Ala
Gly Ser Arg Pro Ile Gln Leu Pro Phe Ile Pro His Glu Asp 145 150 155
160 Pro Arg Val Trp Asp Ser Thr Asp Ala Leu Glu Leu Lys Ser Val Pro
165 170 175 Lys Arg Met Leu Val Met Gly Gly Gly Ile Ile Gly Leu Glu
Met Gly 180 185 190 Thr Val Tyr His Ala Leu Gly Ser Glu Ile Asp Val
Val Glu Met Phe 195 200 205 Asp Gln Val Ile Pro Ala Ala Asp Lys Asp
Val Val Lys Val Phe Thr 210 215 220
Lys Arg Ile Ser Lys Lys Phe Asn Leu Met Leu Glu Ala Lys Val Thr 225
230 235 240 Ala Val Glu Ala Lys Glu Asp Gly Ile Tyr Val Ser Met Glu
Gly Lys 245 250 255 Lys Ala Pro Ala Glu Ala Gln Arg Tyr Asp Ala Val
Leu Val Ala Ile 260 265 270 Gly Arg Val Pro Asn Gly Lys Asn Leu Asp
Ala Gly Lys Ala Gly Val 275 280 285 Glu Val Asp Asp Arg Gly Phe Ile
Arg Val Asp Lys Gln Met Arg Thr 290 295 300 Asn Val Pro His Ile Phe
Ala Ile Gly Asp Ile Val Gly Gln Pro Met 305 310 315 320 Leu Ala His
Lys Gly Val His Glu Gly His Val Ala Ala Glu Val Ile 325 330 335 Ser
Gly Leu Lys His Tyr Phe Asp Pro Lys Val Ile Pro Ser Ile Ala 340 345
350 Tyr Thr Lys Pro Glu Val Ala Trp Val Gly Leu Thr Glu Lys Glu Ala
355 360 365 Lys Glu Lys Gly Ile Ser Tyr Glu Thr Ala Thr Phe Pro Trp
Ala Ala 370 375 380 Ser Gly Arg Ala Ile Ala Ser Asp Cys Ala Asp Gly
Met Thr Lys Leu 385 390 395 400 Ile Phe Asp Lys Glu Thr His Arg Val
Ile Gly Gly Ala Ile Val Gly 405 410 415 Thr Asn Gly Gly Glu Leu Leu
Gly Glu Ile Gly Leu Ala Ile Glu Met 420 425 430 Gly Cys Asp Ala Glu
Asp Ile Ala Leu Thr Ile His Ala His Pro Thr 435 440 445 Leu His Glu
Ser Val Gly Leu Ala Ala Glu Val Phe Glu Gly Ser Ile 450 455 460 Thr
Asp Leu Pro Asn Ala Lys Ala Lys Lys Lys 465 470 475
80347DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 80ataataatac atatgaacca tgcgagttac
gggcctataa gccaggcgag atatgatcta 60tatcaatttc tcatctataa tgctttgtta
gtatctcgtc gccgacttaa taaagagaga 120gttagtgtga aagctgacaa
cccttttgat cttttacttc ctgctgcaat ggccaaagtg 180gccgaagagg
cgggtgtcta taaagcaacg aaacatccgc ttaagacttt ctatctggcg
240attaccgccg gtgttttcat ctcaatcgca ttcaccactg gcacaggcac
agaaggtagg 300tgttacatgt cagaacgttt acacaatgac gtggatccta ttattat
347814678DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 81aagaggtaaa agaataatgg ctatcgaaat
caaagtaccg gacatcgggg ctgatgaagt 60tgaaatcacc gagatcctgg tcaaagtggg
cgacaaagtt gaagccgaac agtcgctgat 120caccgtagaa ggcgacaaag
cctctatgga agttccgtct ccgcaggcgg gtatcgttaa 180agagatcaaa
gtctctgttg gcgataaaac ccagaccggc gcactgatta tgattttcga
240ttccgccgac ggtgcagcag acgctgcacc tgctcaggca gaagagaaga
aagaagcagc 300tccggcagca gcaccagcgg ctgcggcggc aaaagacgtt
aacgttccgg atatcggcag 360cgacgaagtt gaagtgaccg aaatcctggt
gaaagttggc gataaagttg aagctgaaca 420gtcgctgatc accgtagaag
gcgacaaggc ttctatggaa gttccggctc cgtttgctgg 480caccgtgaaa
gagatcaaag tgaacgtggg tgacaaagtg tctaccggct cgctgattat
540ggtcttcgaa gtcgcgggtg aagcaggcgc ggcagctccg gccgctaaac
aggaagcagc 600tccggcagcg gcccctgcac cagcggctgg cgtgaaagaa
gttaacgttc cggatatcgg 660cggtgacgaa gttgaagtga ctgaagtgat
ggtgaaagtg ggcgacaaag ttgccgctga 720acagtcactg atcaccgtag
aaggcgacaa agcttctatg gaagttccgg cgccgtttgc 780aggcgtcgtg
aaggaactga aagtcaacgt tggcgataaa gtgaaaactg gctcgctgat
840tatgatcttc gaagttgaag gcgcagcgcc tgcggcagct cctgcgaaac
aggaagcggc 900agcgccggca ccggcagcaa aagctgaagc cccggcagca
gcaccagctg cgaaagcgga 960aggcaaatct gaatttgctg aaaacgacgc
ttatgttcac gcgactccgc tgatccgccg 1020tctggcacgc gagtttggtg
ttaaccttgc gaaagtgaag ggcactggcc gtaaaggtcg 1080tatcctgcgc
gaagacgttc aggcttacgt gaaagaagct atcaaacgtg cagaagcagc
1140tccggcagcg actggcggtg gtatccctgg catgctgccg tggccgaagg
tggacttcag 1200caagtttggt gaaatcgaag aagtggaact gggccgcatc
cagaaaatct ctggtgcgaa 1260cctgagccgt aactgggtaa tgatcccgca
tgttactcac ttcgacaaaa ccgatatcac 1320cgagttggaa gcgttccgta
aacagcagaa cgaagaagcg gcgaaacgta agctggatgt 1380gaagatcacc
ccggttgtct tcatcatgaa agccgttgct gcagctcttg agcagatgcc
1440tcgcttcaat agttcgctgt cggaagacgg tcagcgtctg accctgaaga
aatacatcaa 1500catcggtgtg gcggtggata ccccgaacgg tctggttgtt
ccggtattca aagacgtcaa 1560caagaaaggc atcatcgagc tgtctcgcga
gctgatgact atttctaaga aagcgcgtga 1620cggtaagctg actgcgggcg
aaatgcaggg cggttgcttc accatctcca gcatcggcgg 1680cctgggtact
acccacttcg cgccgattgt gaacgcgccg gaagtggcta tcctcggcgt
1740ttccaagtcc gcgatggagc cggtgtggaa tggtaaagag ttcgtgccgc
gtctgatgct 1800gccgatttct ctctccttcg accaccgcgt gatcgacggt
gctgatggtg cccgtttcat 1860taccatcatt aacaacacgc tgtctgacat
tcgccgtctg gtgatgtaag taaaagagcc 1920ggcccaacgg ccggcttttt
tctggtaatc tcatgaatgt attgaggtta ttagcgaata 1980gacaaatcgg
ttgccgtttg ttaagccagg cgagatatga tctatatcaa tttctcatct
2040ataatgcttt gttagtatct cgtcgccgac ttaataaaga gagagttagt
cttctatatc 2100acagcaagaa ggtaggtgtt acatgatgag tactgaaatc
aaaactcagg tcgtggtact 2160tggggcaggc cccgcaggtt actctgcagc
cttccgttgc gctgatttag gtctggaaac 2220cgtcatcgta gaacgttaca
gcaccctcgg tggtgtttgt ctgaacgtgg gttgtatccc 2280ttctaaagcg
ctgctgcacg tggcaaaagt tatcgaagaa gcgaaagcgc tggccgaaca
2340cggcatcgtt ttcggcgaac cgaaaactga cattgacaag atccgcacct
ggaaagaaaa 2400agtcatcact cagctgaccg gtggtctggc tggcatggcc
aaaggtcgta aagtgaaggt 2460ggttaacggt ctgggtaaat ttaccggcgc
taacaccctg gaagtggaag gcgaaaacgg 2520caaaaccgtg atcaacttcg
acaacgccat catcgcggcg ggttcccgtc cgattcagct 2580gccgtttatc
ccgcatgaag atccgcgcgt atgggactcc accgacgcgc tggaactgaa
2640atctgtaccg aaacgcatgc tggtgatggg cggcggtatc atcggtctgg
aaatgggtac 2700cgtataccat gcgctgggtt cagagattga cgtggtggaa
atgttcgacc aggttatccc 2760ggctgccgac aaagacgtgg tgaaagtctt
caccaaacgc atcagcaaga aatttaacct 2820gatgctggaa gccaaagtga
ctgccgttga agcgaaagaa gacggtattt acgtttccat 2880ggaaggtaaa
aaagcaccgg cggaagcgca gcgttacgac gcagtgctgg tcgctatcgg
2940ccgcgtaccg aatggtaaaa acctcgatgc aggtaaagct ggcgtggaag
ttgacgatcg 3000cggcttcatc cgcgttgaca aacaaatgcg caccaacgtg
ccgcacatct ttgctatcgg 3060cgatatcgtc ggtcagccga tgctggcgca
caaaggtgtc catgaaggcc acgttgccgc 3120agaagttatc tccggtctga
aacactactt cgatccgaaa gtgatcccat ccatcgccta 3180cactaaacca
gaagtggcat gggtcggtct gaccgagaaa gaagcgaaag agaaaggcat
3240cagctacgaa accgccacct tcccgtgggc tgcttccggc cgtgctatcg
cttctgactg 3300cgcagatggt atgaccaaac tgatcttcga caaagagacc
caccgtgtta tcggcggcgc 3360gattgtcggc accaacggcg gcgagctgct
gggtgagatc ggcctggcta tcgagatggg 3420ctgtgacgct gaagacatcg
ccctgaccat ccacgctcac ccgactctgc acgagtccgt 3480tggcctggcg
gcggaagtgt tcgaaggcag catcaccgac ctgccaaacg ccaaagcgaa
3540gaaaaagtaa ctttttcttt caggaaaaaa gcataagcgg ctccgggagc
cgcttttttt 3600atgcctgatg tttagaacta tgtcactgtt cataaaccgc
tacacctcat acatacttta 3660agggcgaatt ctgcagatat ccatcacact
ggcggccgct cgagcatgca tctagcacat 3720ccggcaatta aaaaagcggc
taaccacgcc gcttttttta cgtctgcaat ttacctttcc 3780agtcttcttg
ctccacgttc agagagacgt tcgcatactg ctgaccgttg ctcgttattc
3840agcctgacag tatggttact gtcgtttaga cgttgtgggc ggctctcctg
aactttctcc 3900cgaaaaacct gacgttgttc aggtgatgcc gattgaacac
gctggcgggc gttatcacgt 3960tgctgttgat tcagtgggcg ctgctgtact
ttttccttaa acacctggcg ctgctctggt 4020gatgcggact gaatacgctc
acgcgctgcg tctcttcgct gctggttctg cgggttagtc 4080tgcattttct
cgcgaaccgc ctggcgctgc tcaggcgagg cggactgaat gcgctcacgc
4140gctgcctctc ttcgctgctg gatcttcggg ttagtctgca ttctctcgcg
aactgcctgg 4200cgctgctcag gcgaggcgga ctgataacgc tgacgagcgg
cgtccttttg ttgctgggtc 4260agtggttggc gacggctgaa gtcgtggaag
tcgtcatagc tcccatagtg ttcagcttca 4320ttaaaccgct gtgccgctgc
ctgacgttgg gtacctcgtg taatgactgg tgcggcgtgt 4380gttcgttgct
gaaactgatt tgctgccgcc tgacgctggc tgtcgcgcgt tggggcaggt
4440aattgcgtgg cgctcattcc gccgttgaca tcggtttgat gaaaccgctt
tgccatatcc 4500tgatcatgat agggcacacc attacggtag tttggattgt
gccgccatgc catattctta 4560tcagtaagat gctcaccggt gatacggttg
aaattgttga cgtcgatatt gatgttgtcg 4620ccgttgtgtt gccagccatt
accgtcacga tgaccgccat cgtggtgatg ataatcat 4678821114DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
82caaaaaaccg gagtctgtgc tccggttttt tattatccgc taatcaatta catatgaata
60tcctccttag ttcctattcc gaagttccta ttctctagaa agtataggaa cttcggcgcg
120cctacctgtg acggaagatc acttcgcaga ataaataaat cctggtgtcc
ctgttgatac 180cgggaagccc tgggccaact tttggcgaaa atgagacgtt
gatcggcacg taagaggttc 240caactttcac cataatgaaa taagatcact
accgggcgta ttttttgagt tgtcgagatt 300ttcaggagct aaggaagcta aa atg
gag aaa aaa atc act gga tat acc acc 352 Met Glu Lys Lys Ile Thr Gly
Tyr Thr Thr 1 5 10 gtt gat ata tcc caa tgg cat cgt aaa gaa cat ttt
gag gca ttt cag 400Val Asp Ile Ser Gln Trp His Arg Lys Glu His Phe
Glu Ala Phe Gln 15 20 25 tca gtt gct caa tgt acc tat aac cag acc
gtt cag ctg gat att acg 448Ser Val Ala Gln Cys Thr Tyr Asn Gln Thr
Val Gln Leu Asp Ile Thr 30 35 40 gcc ttt tta aag acc gta aag aaa
aat aag cac aag ttt tat ccg gcc 496Ala Phe Leu Lys Thr Val Lys Lys
Asn Lys His Lys Phe Tyr Pro Ala 45 50 55 ttt att cac att ctt gcc
cgc ctg atg aat gct cat ccg gaa tta cgt 544Phe Ile His Ile Leu Ala
Arg Leu Met Asn Ala His Pro Glu Leu Arg 60 65 70 atg gca atg aaa
gac ggt gag ctg gtg ata tgg gat agt gtt cac cct 592Met Ala Met Lys
Asp Gly Glu Leu Val Ile Trp Asp Ser Val His Pro 75 80 85 90 tgt tac
acc gtt ttc cat gag caa act gaa acg ttt tca tcg ctc tgg 640Cys Tyr
Thr Val Phe His Glu Gln Thr Glu Thr Phe Ser Ser Leu Trp 95 100 105
agt gaa tac cac gac gat ttc cgg cag ttt cta cac ata tat tcg caa
688Ser Glu Tyr His Asp Asp Phe Arg Gln Phe Leu His Ile Tyr Ser Gln
110 115 120 gat gtg gcg tgt tac ggt gaa aac ctg gcc tat ttc cct aaa
ggg ttt 736Asp Val Ala Cys Tyr Gly Glu Asn Leu Ala Tyr Phe Pro Lys
Gly Phe 125 130 135 att gag aat atg ttt ttc gtc tca gcc aat ccc tgg
gtg agt ttc acc 784Ile Glu Asn Met Phe Phe Val Ser Ala Asn Pro Trp
Val Ser Phe Thr 140 145 150 agt ttt gat tta aac gtg gcc aat atg gac
aac ttc ttc gcc ccc gtt 832Ser Phe Asp Leu Asn Val Ala Asn Met Asp
Asn Phe Phe Ala Pro Val 155 160 165 170 ttc acc atg ggc aaa tat tat
acg caa ggc gac aag gtg ctg atg ccg 880Phe Thr Met Gly Lys Tyr Tyr
Thr Gln Gly Asp Lys Val Leu Met Pro 175 180 185 ctg gcg att cag gtt
cat cat gcc gtt tgt gat ggc ttc cat gtc ggc 928Leu Ala Ile Gln Val
His His Ala Val Cys Asp Gly Phe His Val Gly 190 195 200 aga tgc tta
atg aat aca aca gta ctg cga tgagtggcag ggcggggcgt 978Arg Cys Leu
Met Asn Thr Thr Val Leu Arg 205 210 aaggcgcgcc atttaaatga
agttcctatt ccgaagttcc tattctctag aaagtatagg 1038aacttcgaag
cagctccagc ctacaccctt cttcagggct gactgtttgc ataaaaattc
1098atctgtatgc acaata 111483212PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 83Met Glu Lys Lys Ile Thr
Gly Tyr Thr Thr Val Asp Ile Ser Gln Trp 1 5 10 15 His Arg Lys Glu
His Phe Glu Ala Phe Gln Ser Val Ala Gln Cys Thr 20 25 30 Tyr Asn
Gln Thr Val Gln Leu Asp Ile Thr Ala Phe Leu Lys Thr Val 35 40 45
Lys Lys Asn Lys His Lys Phe Tyr Pro Ala Phe Ile His Ile Leu Ala 50
55 60 Arg Leu Met Asn Ala His Pro Glu Leu Arg Met Ala Met Lys Asp
Gly 65 70 75 80 Glu Leu Val Ile Trp Asp Ser Val His Pro Cys Tyr Thr
Val Phe His 85 90 95 Glu Gln Thr Glu Thr Phe Ser Ser Leu Trp Ser
Glu Tyr His Asp Asp 100 105 110 Phe Arg Gln Phe Leu His Ile Tyr Ser
Gln Asp Val Ala Cys Tyr Gly 115 120 125 Glu Asn Leu Ala Tyr Phe Pro
Lys Gly Phe Ile Glu Asn Met Phe Phe 130 135 140 Val Ser Ala Asn Pro
Trp Val Ser Phe Thr Ser Phe Asp Leu Asn Val 145 150 155 160 Ala Asn
Met Asp Asn Phe Phe Ala Pro Val Phe Thr Met Gly Lys Tyr 165 170 175
Tyr Thr Gln Gly Asp Lys Val Leu Met Pro Leu Ala Ile Gln Val His 180
185 190 His Ala Val Cys Asp Gly Phe His Val Gly Arg Cys Leu Met Asn
Thr 195 200 205 Thr Val Leu Arg 210 842521DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
84ttatttggtg atattggtac caatatcatg cagcaaacgg tgcaacattg ccgtgtctcg
60ttgctctaaa agccccaggc gttgttgtaa ccagtcgacc agttttatgt catctgccac
120tgccagagtc gtcagcaatg tcatggctcg ttcgcgtaaa gcttgcagtt
gatgttggtc 180tgccgttgca tcacttttcg ccggttgttg tattaatgtt
gctaattgat agcaatagac 240catcaccgcc tgccccagat tgagcgaagg
ataatccgcc accatcggca caccagtaag 300aacgtcagcc aacgctaact
cttcgttagt caacccggaa tcttcgcgac caaacaccag 360cgcggcatgg
ctcatccatg aagatttttc ctctaacagc ggcaccagtt caactggcgt
420ggcgtagtaa tgatatttcg cccgactgcg cgcagtggtg gcgacagtga
aatcgacatc 480gtgtaacgat tcagccaatg tcgggaaaac tttaatatta
tcaataatat caccagatcc 540atgtgcgacc cagcgggtgg ctggctccag
gtgtgcctga ctatcgacaa tccgcagatc 600gctaaacccc atcgttttca
ttgcccgcgc cgctgcccca atattttctg ctctggcggg 660tgcgaccaga
ataatcgtta tacgcatatt gccactcttc ttgatcaaat aaccgcgaac
720cgggtgatca ctgtcaactt attacgcggt gcgaatttac aaattcttaa
cgtaagtcgc 780agaaaaagcc ctttacttag cttaaaaaag gctaaactat
ttcctgactg tactaacggt 840tgagttgtta aaaaatgcta catatccttc
tgtttactta ggataatttt ataaaaaata 900aatctcgaca attggattca
ccacgtttat tagttgtatg atgcaactag ttggattatt 960aaaataatgt
gacgaaagct agcatttaga tacgatgatt tcatcaaact gttaacgtgc
1020tacaattgaa cttgatatat gtcaacgaag cgtagtttta ttgggtgtcc
ggcccctctt 1080agcctgttat gttgctgtta aaatggttag gatgacagcc
gtttttgaca ctgtcgggtc 1140ctgagggaaa gtacccacga ccaagctaat
gatgttgttg acgttgatgg aaagtgcatc 1200aagaacgcaa ttacgtactt
tagtcatgtt acgccgatca tgttaatttg cagcatgcat 1260caggcaggtc
agggactttt gtacttcctg tttcgattta gttggcaatt taggtagcaa
1320acgaattcat cggctttacc accgtcaaaa aaaacggcgc tttttagcgc
cgtttttatt 1380tttcaacctt atttccagat acgtaactca tcgtccgttg
taacttcttt actggctttc 1440attttcggca gtgaaaacgc ataccagtcg
atattacggg tcacaaacat catgccggcc 1500agcgccacca ccagcacact
ggttcccaac aacagcgcgc tatcggcaga gttgagcagt 1560ccccacatca
caccatccag caacaacagc gcgagggtaa acaacatgct gttgcaccaa
1620cctttcaata ccgcttgcaa ataaataccg ttcattatcg ccccaatcag
actggcgatt 1680atccatgcca cggtaaaacc ggtatgttca gaaagcgcca
gcaagagcaa ataaaacatc 1740accaatgaaa gccccaccag caaatattgc
attgggtgta aacgttgcgc ggtgagcgtt 1800tcaaaaacaa agaacgccat
aaaagtcagt gcaatcagca gaatggcgta cttagtcgcc 1860cggtcagtta
attggtattg atcggctggc gtcgttactg cgacgctaaa cgccgggaag
1920ttttcccagc cggtatcatt gcctgaagca aaacgctcac cgagattatt
agcaaaccag 1980ctgctttgcc agtgcgcctg aaaacctgac tcgctaactt
cccgtttggc tggtagaaaa 2040tcacctaaaa aactgggatg cggccagttg
ctggttaagg tcatttcgct attacgcccg 2100ccaggcacca cagaaagatc
gccggtaccg cttaaattca gggccatatt cagcttcagg 2160ttctgcttcc
gccagtcccc ttcaggtaaa gggatatgca cgccctgccc gccttgctct
2220aacccggtgc cgggttcaat ggtcagcgcc gttccgttaa cttcaggcgc
tttcaccaca 2280ccaataccac gcgcatcccc gacgctaatc acaataaatg
gcttgcctaa ggtgatattt 2340ggcgcgttga gttcgctaag acgcgaaaca
tcgaaatcgg cttttaacgt taaatcactg 2400tgccagacct gaccggtata
aatccctatc ttgcgttctt ccacgttctg attgccatca 2460accatcaatg
actcaggtaa ccaaaaatgg ataaaacttc gtttccgctg cagggtttta 2520t
2521853010DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 85aagccacagc aggatgccca ctgcaacaaa
ggtgatcaca ccggaaacgc gatggagaat 60ggacgctatc gccgtgatgg ggaaccggat
ggtctgtagg tccagattaa caggtctttg 120ttttttcaca tttcttatca
tgaataacgc ccacatgctg ttcttattat tccctgggga 180ctacgggcac
agaggttaac tttctgttac ctggagacgt cgggatttcc ttcctccggt
240ctgcttgcgg gtcagacagc gtcctttcta taactgcgcg tcatgcaaaa
cactgcttcc 300agatgcgaaa acgacacgtt acaacgctgg gtggctcggg
attgcagggt gttccggaga 360cctggcggca gtataggctg ttcacaaaat
cattacaatt aacctacata tagtttgtcg 420ggttttatcc tgaacagtga
tccaggtcac gataacaaca tttatttaat ttttaatcat 480ctaatttgac
aatcattcaa caaagttgtt acaaacatta ccaggaaaag catataatgc
540gtaaaagtta tgaagtcggt atttcaccta agattaactt atgtaacagt
gtggaagtat 600tgaccaattc attcgggaca gttattagtg gtagacaagt
ttaataattc ggattgctaa 660gtacttgatt cgccatttat tcgtcatcaa
tggatccttt acctgcaagc gcccagagct 720ctgtacccag gttttcccct
ctttcacaga gcggcgagcc aaataaaaaa cgggtaaagc 780caggttgatg
tgcgaaggca aatttaagtt ccggcagtct tacgcaataa ggcgctaagg
840agaccttaaa tggctgatac aaaagcaaaa ctcaccctca acggggatac
agctgttgaa
900ctggatgtgc tgaaaggcac gctgggtcaa gatgttattg atatccgtac
tctcggttca 960aaaggtgtgt tcacctttga cccaggcttc acttcaaccg
catcctgcga atctaaaatt 1020acttttattg atggtgatga aggtattttg
ctgcaccgcg gtttcccgat cgatcagctg 1080gcgaccgatt ctaactacct
ggaagtttgt tacatcctgc tgaatggtga aaaaccgact 1140caggaacagt
atgacgaatt taaaactacg gtgacccgtc ataccatgat ccacgagcag
1200attacccgtc tgttccatgc tttccgtcgc gactcgcatc caatggcagt
catgtgtggt 1260attaccggcg cgctggcggc gttctatcac gactcgctgg
atgttaacaa tcctcgtcac 1320cgtgaaattg ccgcgttcct cctgctgtcg
aaaatgccga ccatggccgc gatgtgttac 1380aagtattcca ttggtcagcc
atttgtttac ccgcgcaacg atctctccta cgccggtaac 1440ttcctgaata
tgatgttctc cacgccgtgc gaaccgtatg aagttaatcc gattctggaa
1500cgtgctatgg accgtattct gatcctgcac gctgaccatg aacagaacgc
ctctacctcc 1560accgtgcgta ccgctggctc ttcgggtgcg aacccgtttg
cctgtatcgc agcaggtatt 1620gcttcactgt ggggacctgc gcacggcggt
gctaacgaag cggcgctgaa aatgctggaa 1680gaaatcagct ccgttaaaca
cattccggaa tttgttcgtc gtgcgaaaga caaaaatgat 1740tctttccgcc
tgatgggctt cggtcaccgc gtgtacaaaa attacgaccc gcgcgccacc
1800gtaatgcgtg aaacctgcca tgaagtgctg aaagagctgg gcacgaagga
tgacctgctg 1860gaagtggcta tggagctgga aaacatcgcg ctgaacgacc
cgtactttat cgagaagaaa 1920ctgtacccga acgtcgattt ctactctggt
atcatcctga aagcgatggg tattccgtct 1980tccatgttca ccgtcatttt
cgcaatggca cgtaccgttg gctggatcgc ccactggagc 2040gaaatgcaca
gtgacggtat gaagattgcc cgtccgcgtc agctgtatac aggatatgaa
2100aaacgcgact ttaaaagcga tatcaagcgt taatggttga ttgctaagtt
gtaaatattt 2160taacccgccg ttcatatggc gggttgattt ttatatgcct
aaacacaaaa aattgtaaaa 2220ataaaatcca ttaacagacc tatatagata
tttaaaaaga atagaacagc tcaaattatc 2280agcaacccaa tactttcaat
taaaaacttc atggtagtcg catttataac cctatgaaaa 2340tgacgtctat
ctataccccc ctatatttta ttcatcatac aacaaattca tgataccaat
2400aatttagttt tgcatttaat aaaactaaca atatttttaa gcaaaactaa
aaactagcaa 2460taatcaaata cgatattctg gcgtagctat acccctattc
tatatcctta aaggactctg 2520ttatgtttaa aggacaaaaa acattggccg
cactggccgt atctctgctg ttcactgcac 2580ctgtttatgc tgctgatgaa
ggttctggcg aaattcactt taagggggag gttattgaag 2640caccttgtga
aattcatcca gaagatattg ataaaaacat agatcttgga caagtcacga
2700caacccatat aaaccgggag catcatagca ataaagtggc cgtcgacatt
cgcttgatca 2760actgtgatct gcctgcttct gacaacggta gcggaatgcc
ggtatccaaa gttggcgtaa 2820ccttcgatag cacggctaag acaactggtg
ctacgccttt gttgagcaac accagtgcag 2880gcgaagcaac tggggtcggt
gtacgactga tggacaaaaa tgacggtaac atcgtattag 2940gttcagccgc
gccagatctt gacctggatg caagctcatc agaacagacg ctgaactttt
3000tcgcctggat 3010864180DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 86cgcgatgtcg
acgtcacgaa actgaaaaaa ccgctctaca ttctggcgac tgctgatgaa 60gaaaccagta
tggccggagc gcgttatttt gccgaaacta ccgccctgcg cccggattgc
120gccatcattg gcgaaccgac gtcactacaa ccggtacgcg cacataaagg
tcatatctct 180aacgccatcc gtattcaggg ccagtcgggg cactccagcg
atccagcacg cggagttaac 240gctatcgaac taatgcacga cgccatcggg
catattttgc aattgcgcga taacctgaaa 300gaacgttatc actacgaagc
gtttaccgtg ccatacccta cgctcaacct cgggcatatt 360cacggtggcg
acgcttctaa ccgtatttgc gcttgctgtg agttgcatat ggatattcgt
420ccgctgcctg gcatgacact caatgaactt aatggtttgc tcaacgatgc
attggctccg 480gtgagcgaac gctggccggg tcgtctgacg gtcgacgagc
tgcatccgcc gatccctggc 540tatgaatgcc caccgaatca tcaactggtt
gaagtggttg agaaattgct cggagcaaaa 600accgaagtgg tgaactactg
taccgaagcg ccgtttattc aaacgttatg cccgacgctg 660gtgttggggc
ctggctcaat taatcaggct catcaacctg atgaatatct ggaaacacgg
720tttatcaagc ccacccgcga actgataacc caggtaattc accatttttg
ctggcattaa 780aacgtaggcc ggataaggcg ctcgcgccgc atccggcgct
gttgccaaac tccagtgccg 840caataatgtc ggatgcgatg cttgcgcatc
ttatccgacc tacagtgact caaacgatgc 900ccaaccgtag gccggataag
gcgctcgcgc cgcatccggc actgttgcca aactccagtg 960ccgcaataat
gtcggatgcg atacttgcgc atcttatccg accgacagtg actcaaacga
1020tgcccaactg taggccggat aaggcgctcg cgccgcatcc ggcactgttg
ccaaactcca 1080gtgccgcaat aatgtcggat gcgatacttg cgcatcttat
ccgacctaca cctttggtgt 1140tacttggggc gattttttaa catttccata
agttacgctt atttaaagcg tcgtgaattt 1200aatgacgtaa attcctgcta
tttattcgtt tgctgaagcg atttcgcagc atttgacgtc 1260accgctttta
cgtggcttta taaaagacga cgaaaagcaa agcccgagca tattcgcgcc
1320aatgctagca agaggagaag tcgacatgac agacttaaat aaagtggtaa
aagaacttga 1380agctcttggt atttatgacg taaaagaagt tgtttacaat
ccaagctacg agcaattgtt 1440cgaagaagaa actaaaccag gtttagaagg
ctttgaaaaa ggtactttaa ctacgactgg 1500tgcagtggca gtagatacag
gtatcttcac aggtcgttct ccaaaagata aatatatcgt 1560gttagatgaa
aaaaccaaag atactgtttg gtggacatct gaaacagcaa aaaacgacaa
1620caagccaatg aaccaagcta catggcaaag cttaaaagac ttggtaacca
accagctttc 1680tcgtaaacgc ttatttgtag ttgatggttt ctgtggtgcg
agcgaacacg accgtattgc 1740agtacgtatt gtcactgaag tagcgtggca
agcacatttt gtaaaaaata tgtttattcg 1800cccaactgaa gaacaactca
aaaattttga accagatttc gttgtaatga atggttctaa 1860agtaaccaat
ccaaactgga aagaacaagg tttaaattca gaaaactttg ttgctttcaa
1920cttgactgaa cgcattcaat taatcggtgg tacttggtac ggcggtgaaa
tgaaaaaagg 1980tatgttctca atcatgaact acttcctacc acttaaaggt
gttggtgcaa tgcactgctc 2040agctaacgtt ggtaaagatg gcgatgtagc
aatcttcttc ggcttatctg gcacaggtaa 2100aacaaccctt tcaacggatc
caaaacgtga attaatcggt gacgatgaac acggctggga 2160tgatgtgggt
atctttaact ttgaaggtgg ttgctatgcg aaaaccattc acctttcaga
2220agaaaatgaa ccagatattt accgcgctat ccgtcgcgac gcattattag
aaaacgtggt 2280tgttcgtgca gatggttctg ttgatttcga tgatggttca
aaaacagaaa atactcgcgt 2340gtcttaccca atttatcaca ttgataacat
tgtaaaacca gtttctcgtg caggtcacgc 2400aactaaagtg attttcttaa
ctgcagatgc atttggcgta ttaccaccag tatctaaatt 2460gacaccagaa
caaactaaat actacttctt atctggtttc acagcaaaat tagcaggtac
2520tgaacgtggt attactgaac caactccaac tttctcagca tgtttcggtg
ctgcgttctt 2580aacccttcac ccaactcaat atgcagaagt gttagtaaaa
cgtatgcaag cagtgggtgc 2640tgaagcttac ttagtaaata ctggttggaa
tggcacaggc aaacgtatct caatcaaaga 2700tactcgcgga atcattgatg
caatcttaga tggctcaatt gaaaaagctg aaatgggcga 2760attaccaatc
tttaacttag ccattcctaa agcattacca ggtgtagatt ctgcaatctt
2820agatcctcgc gatacttacg cagataaagc acaatggcaa tcaaaagctg
aagacttagc 2880aggtcgtttt gtgaaaaact ttgttaaata tgcaactaac
gaagaaggca aagctttaat 2940tgcagctggt cctaaagctt aatctagaaa
gcttcctaga ggcatcaaat aaaacgaaag 3000gctcagtcga aagactgggc
ctttcgtttt atctgttgtt tgtcggtgaa cgctctcctg 3060agtaggacga
attcacttct gttctaacac cctcgttttc aatatatttc tgtctgcatt
3120ttattcaaat tctgaatata ccttcagata tccttaagga attgtcgtta
cattcggcga 3180tattttttca agacaggttc ttactatgca ttccacagaa
gtccaggcta aacctctttt 3240tagctggaaa gccctgggtt gggcactgct
ctacttttgg tttttctcta ctctgctaca 3300ggccattatt tacatcagtg
gttatagtgg cactaacggc attcgcgact cgctgttatt 3360cagttcgctg
tggttgatcc cggtattcct ctttccgaag cggattaaaa ttattgccgc
3420agtaatcggc gtggtgctat gggcggcctc tctggcggcg ctgtgctact
acgtcatcta 3480cggtcaggag ttctcgcaga gcgttctgtt tgtgatgttc
gaaaccaaca ccaacgaagc 3540cagcgagtat ttaagccagt atttcagcct
gaaaattgtg cttatcgcgc tggcctatac 3600ggcggtggca gttctgctgt
ggacacgcct gcgcccggtc tatattccaa agccgtggcg 3660ttatgttgtc
tcttttgccc tgctttatgg cttgattctg catccgatcg ccatgaatac
3720gtttatcaaa aacaagccgt ttgagaaaac gttggataac ctggcctcgc
gtatggagcc 3780tgccgcaccg tggcaattcc tgaccggcta ttatcagtat
cgtcagcaac taaactcgct 3840aacaaagtta ctgaatgaaa ataatgcctt
gccgccactg gctaatttca aagatgaatc 3900gggtaacgaa ccgcgcactt
tagtgctggt gattggcgag tcgacccagc gcggacgcat 3960gagtctgtac
ggttatccgc gtgaaaccac gccggagctg gatgcgctgc ataaaaccga
4020tccgaatctg accgtgttta ataacgtagt tacgtctcgt ccgtacacca
ttgaaatcct 4080gcaacaggcg ctgacctttg ccaatgaaaa gaacccggat
ctgtatctga cgcagccgtc 4140gctgatgaac atgatgaaac aggcgggtta
taaaaccttc 4180874960DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 87aataggcgta
tcacgaggcc ctttcgtctt cacctcgaga attgtgagcg gataacaatt 60gacattgtga
gcggataaca agatactgag cacatcagca ggacgcactg accgaattca
120attaagctag caagaggaga agtcgagatg aacttacatg aatatcaggc
aaaacaactt 180tttgcccgct atggcttacc agcaccggtg ggttatgcct
gtactactcc gcgcgaagca 240gaagaagccg cttcaaaaat cggtgccggt
ccgtgggtag tgaaatgtca ggttcacgct 300ggtggccgcg gtaaagcggg
cggtgtgaaa gttgtaaaca gcaaagaaga catccgtgct 360tttgcagaaa
actggctggg caagcgtctg gtaacgtatc aaacagatgc caatggccaa
420ccggttaacc agattctggt tgaagcagcg accgatatcg ctaaagagct
gtatctcggt 480gccgttgttg accgtagttc ccgtcgtgtg gtctttatgg
cctccaccga aggcggcgtg 540gaaatcgaaa aagtggcgga agaaactccg
cacctgatcc ataaagttgc gcttgatccg 600ctgactggcc cgatgccgta
tcagggacgc gagctggcgt tcaaactggg tctggaaggt 660aaactggttc
agcagttcac caaaatcttc atgggcctgg cgaccatttt cctggagcgc
720gacctggcgt tgatcgaaat caacccgctg gtcatcacca aacagggcga
tctgatttgc 780ctcgacggca aactgggcgc tgacggcaac gcactgttcc
gccagcctga tctgcgcgaa 840atgcgtgacc agtcgcagga agatccgcgt
gaagcacagg ctgcacagtg ggaactgaac 900tacgttgcgc tggacggtaa
catcggttgt atggttaacg gcgcaggtct ggcgatgggt 960acgatggaca
tcgttaaact gcacggcggc gaaccggcta acttccttga cgttggcggc
1020ggcgcaacca aagaacgtgt aaccgaagcg ttcaaaatca tcctctctga
cgacaaagtg 1080aaagccgttc tggttaacat cttcggcggt atcgttcgtt
gcgacctgat cgctgacggt 1140atcatcggcg cggtagcaga agtgggtgtt
aacgtaccgg tcgtggtacg tctggaaggt 1200aacaacgccg aactcggcgc
gaagaaactg gctgacagcg gcctgaatat tattgcagca 1260aaaggtctga
cggatgcagc tcagcaggtt gttgccgcag tggaggggaa ataatgtcca
1320ttttaatcga taaaaacacc aaggttatct gccagggctt taccggtagc
caggggactt 1380tccactcaga acaggccatt gcatacggca ctaaaatggt
tggcggcgta accccaggta 1440aaggcggcac cacccacctc ggcctgccgg
tgttcaacac cgtgcgtgaa gccgttgctg 1500ccactggcgc taccgcttct
gttatctacg taccagcacc gttctgcaaa gactccattc 1560tggaagccat
cgacgcaggc atcaaactga ttatcaccat cactgaaggc atcccgacgc
1620tggatatgct gaccgtgaaa gtgaagctgg atgaagcagg cgttcgtatg
atcggcccga 1680actgcccagg cgttatcact ccgggtgaat gcaaaatcgg
tatccagcct ggtcacattc 1740acaaaccggg taaagtgggt atcgtttccc
gttccggtac actgacctat gaagcggtta 1800aacagaccac ggattacggt
ttcggtcagt cgacctgtgt cggtatcggc ggtgacccga 1860tcccgggctc
taactttatc gacattctcg aaatgttcga aaaagatccg cagaccgaag
1920cgatcgtgat gatcggtgag atcggcggta gcgctgaaga agaagcagct
gcgtacatca 1980aagagcacgt taccaagcca gttgtgggtt acatcgctgg
tgtgactgcg ccgaaaggca 2040aacgtatggg ccacgcgggt gccatcattg
ccggtgggaa agggactgcg gatgagaaat 2100tcgctgctct ggaagccgca
ggcgtgaaaa ccgttcgcag cctggcggat atcggtgaag 2160cactgaaaac
tgttctgaaa taatctagca agaggagaag tcgacatgga aatcaaagaa
2220atggtgagcc ttgcacgcaa ggctcagaag gagtatcaag ctacccataa
ccaagaagca 2280gttgacaaca tttgccgagc tgcagcaaaa gttatttatg
aaaatgcagc tattctggct 2340cgcgaagcag tagacgaaac cggcatgggc
gtttacgaac acaaagtggc caagaatcaa 2400ggcaaatcca aaggtgtttg
gtacaacctc cacaataaaa aatcgattgg tatcctcaat 2460atagacgagc
gtaccggtat gatcgagatt gcaaagccta tcggagttgt aggagccgta
2520acgccgacga ccaacccgat cgttactccg atgagcaata tcatctttgc
tcttaagacc 2580tgcaatgcca tcattattgc cccccacccc agatccaaaa
aatgctctgc acacgcagtt 2640cgtctgatca aagaagctat cgctccgttc
aacgtaccgg aaggtatggt tcagatcatc 2700gaagaaccca gcatcgagaa
gacgcaggaa ctcatgggcg ccgtagacgt agtagttgct 2760acgggtggta
tgggcatggt gaagtctgca tattcttcag gaaagccttc tttcggtgtt
2820ggagccggta acgttcaggt gatcgtggat agcaacatcg atttcgaagc
tgctgcagaa 2880aaaatcatca ccggtcgtgc tttcgacaac ggtatcatct
gctcaggcga acagagcatc 2940atctacaacg aggctgacaa ggaagcagtt
ttcacagcat tccgcaacca cggtgcatat 3000ttctgtgacg aagccgaagg
agatcgggct cgtgcagcta tcttcgaaaa tggagccatc 3060gcgaaagatg
tagtaggtca gagcgttgcc ttcattgcca agaaagcaaa catcaatatc
3120cccgagggta cccgtattct cgttgttgaa gctcgcggcg taggagcaga
agacgttatc 3180tgtaaggaaa agatgtgtcc cgtaatgtgc gccctcagct
acaagcactt cgaagaaggt 3240gtagaaatcg cacgtacgaa cctcgccaac
gaaggtaacg gccacacctg tgctatccac 3300tccaacaatc aggcacacat
catcctcgca ggatcagagc tgacggtatc tcgtatcgta 3360gtgaatgctc
cgagtgccac tacagcaggc ggtcacatcc aaaacggtct tgccgtaacc
3420aatacgctcg gatgcggatc atggggtaat aactctatct ccgagaactt
cacttacaag 3480cacctcctca acatttcacg catcgcaccg ttgaattcaa
gcattcacat ccccgatgac 3540aaagaaatct gggaactcta atctagcaag
aggagaagtc gacatgcaac ttttcaaact 3600caagagtgta acacatcact
ttgacacttt tgcagaattt gccaaggaat tctgtcttgg 3660agaacgcgac
ttggtaatta ccaacgagtt catctatgaa ccgtatatga aggcatgcca
3720gctcccctgc cattttgtta tgcaggagaa atatgggcaa ggcgagcctt
ctgacgaaat 3780gatgaataac atcttggcag acatccgtaa tatccagttc
gaccgcgtaa tcggtatcgg 3840aggaggtacg gttattgaca tctctaaact
tttcgttctg aaaggattaa atgatgtact 3900cgatgcattc gaccgcaaaa
tacctcttat caaagagaaa gaactgatca ttgtgcccac 3960aacatgcgga
acgggtagcg aggtgacgaa catttctatc gcagaaatca aaagccgtca
4020caccaaaatg ggattggctg acgatgccat tgttgcagac catgccatca
tcatacctga 4080acttctgaag agcttgcctt tccacttcta cgcatgcagt
gcaatcgatg ctcttatcca 4140tgccatcgag tcatacgtat ctcctaaagc
cagtccatat tctcgtctgt tcagtgaggc 4200ggcttgggac attatcctgg
aagtattcaa gaaaatcgcc gaacacggcc ctgaataccg 4260cttcgaaaag
ctgggagaaa tgatcatggc cagcaactat gccggtatag ccttcggaaa
4320tgcaggagta ggagccgtcc acgcactatc ctacccgttg ggaggcaact
atcacgtgcc 4380gcatggagaa gcaaactatc agttcttcac agaggtattc
aaagtatacc aaaagaagaa 4440tcctttcggc tatatagtcg aactcaactg
gaagctctcc aagatactga actgccagcc 4500cgaatacgta tatccgaagc
tggatgaact tctcggatgc cttcttacca agaaaccttt 4560gcacgaatac
ggcatgaagg acgaagaggt aagaggcttt gcggaatcag tgcttaagac
4620acagcaaaga ttgctcgcca acaactacgt agagcttact gtagatgaga
tcgaaggtat 4680ctacagaaga ctctactaat ctagaaagct tcctagaggc
atcaaataaa acgaaaggct 4740cagtcgaaag actgggcctt tcgttttatc
tgttgtttgt cggtgaacgc tctcctgagt 4800aggacaaatc cgccgcccta
gacctaggcg ttcggctgcg acacgtcttg agcgattgtg 4860taggctggag
ctgcttcgaa gttcctatac tttctagaga ataggaactt cggaatagga
4920actaaggagg atattcatat ggaccatggc taattcccat
4960885083DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 88tcgagaaatt tatcaaaaag agtgttgact
tgtgagcgga taacaatgat acttagattc 60aattgtgagc ggataacaat ttcacacaga
attcaattaa gctagcaaga ggagaagtcg 120acatggccaa cataagttca
ccattcgggc aaaacgaatg gctggttgaa gagatgtacc 180gcaagttccg
cgacgacccc tcctcggtcg atcccagctg gcacgagttc ctggttgact
240acagccccga acccacctcc caaccagctg ccgaaccaac ccgggttacc
tcgccactcg 300ttgccgagcg ggccgctgcg gccgccccgc aggcaccccc
caagccggcc gacaccgcgg 360ccgcgggcaa cggcgtggtc gccgcactgg
ccgccaaaac tgccgttccc ccgccagccg 420aaggtgacga ggtagcggtg
ctgcgcggcg ccgccgcggc cgtcgtcaag aacatgtccg 480cgtcgttgga
ggtgccgacg gcgaccagcg tccgggcggt cccggccaag ctactgatcg
540acaaccggat cgtcatcaac aaccagttga agcggacccg cggcggcaag
atctcgttca 600cgcatttgct gggctacgcc ctggtgcagg cggtgaagaa
attcccgaac atgaaccggc 660actacaccga agtcgacggc aagcccaccg
cggtcacgcc ggcgcacacc aatctcggcc 720tggcgatcga cctgcaaggc
aaggacggga agcgttccct ggtggtggcc ggcatcaagc 780ggtgcgagac
catgcgattc gcgcagttcg tcacggccta cgaagacatc gtacgccggg
840cccgcgacgg caagctgacc actgaagact ttgccggcgt gacgatttcg
ctgaccaatc 900ccggaaccat cggcaccgtg cattcggtgc cgcggctgat
gcccggccag ggcgccatca 960tcggcgtggg cgccatggaa taccccgccg
agtttcaagg cgccagcgag gaacgcatcg 1020ccgagctggg catcggcaaa
ttgatcactt tgacctccac ctacgaccac cgcatcatcc 1080agggcgcgga
atcgggcgac ttcctgcgca ccatccacga gttgctgctc tcggatggct
1140tctgggacga ggtcttccgc gaactgagca tcccatatct gccggtgcgc
tggagcaccg 1200acaaccccga ctcgatcgtc gacaagaacg ctcgcgtcat
gaacttgatc gcggcctacc 1260gcaaccgcgg ccatctgatg gccgataccg
acccgctgcg gttggacaaa gctcggttcc 1320gcagtcaccc cgacctcgaa
gtgctgaccc acggcctgac gctgtgggat ctcgatcggg 1380tgttcaaggt
cgacggcttt gccggtgcgc agtacaagaa actgcgcgac gtgctgggct
1440tgctgcgcga tgcctactgc cgccacatcg gcgtggagta cgcccatatc
ctcgaccccg 1500aacaaaagga gtggctcgaa caacgggtcg agaccaagca
cgtcaaaccc actgtggccc 1560aacagaaata catcctcagc aagctcaacg
ccgccgaggc ctttgaaacg ttcctacaga 1620ccaagtacgt cggccagaag
cggttctcgc tggaaggcgc cgaaagcgtg atcccgatga 1680tggacgcggc
gatcgaccag tgcgctgagc acggcctcga cgaggtggtc atcgggatgc
1740cgcaccgggg ccggctcaac gtgctggcca acatcgtcgg caagccgtac
tcgcagatct 1800tcaccgagtt cgagggcaac ctgaatccgt cgcaggcgca
cggctccggt gacgtcaagt 1860accacctggg cgccaccggg ctgtacctgc
agatgttcgg cgacaacgac attcaggtgt 1920cgctgaccgc caacccgtcg
catctggagg ccgtcgaccc ggtgctggag ggattggtgc 1980gggccaagca
ggatctgctc gaccacggaa gcatcgacag cgacggccaa cgggcgttct
2040cggtggtgcc gctgatgttg catggcgatg ccgcgttcgc cggtcagggt
gtggtcgccg 2100agacgctgaa cctggcgaat ctgccgggct accgcgtcgg
cggcaccatc cacatcatcg 2160tcaacaacca gatcggcttc accaccgcgc
ccgagtattc caggtccagc gagtactgca 2220ccgacgtcgc aaagatgatc
ggggcaccga tctttcacgt caacggcgac gacccggagg 2280cgtgtgtctg
ggtggcgcgg ttggcggtgg acttccgaca acggttcaag aaggacgtcg
2340tcatcgacat gctgtgctac cgccgccgcg ggcacaacga gggtgacgac
ccgtcgatga 2400ccaaccccta catgtacgac gtcgtcgaca ccaagcgcgg
ggcccgcaaa agctacaccg 2460aagccctgat cggacgtggc gacatctcga
tgaaggaggc cgaggacgcg ctgcgcgact 2520accagggcca gctggaacgg
gtgttcaacg aagtgcgcga gctggagaag cacggtgtgc 2580agccgagcga
gtcggtcgag tccgaccaga tgattcccgc ggggctggcc actgcggtgg
2640acaagtcgct gctggcccgg atcggcgatg cgttcctcgc cttgccgaac
ggcttcaccg 2700cgcacccgcg agtccaaccg gtgctggaga agcgccggga
gatggcctat gaaggcaaga 2760tcgactgggc ctttggcgag ctgctggcgc
tgggctcgct ggtggccgaa ggcaagctgg 2820tgcgcttgtc ggggcaggac
agccgccgcg gcaccttctc ccagcggcat tcggttctca 2880tcgaccgcca
cactggcgag gagttcacac cactgcagct gctggcgacc aactccgacg
2940gcagcccgac cggcggaaag ttcctggtct acgactcgcc actgtcggag
tacgccgccg 3000tcggcttcga gtacggctac actgtgggca atccggacgc
cgtggtgctc tgggaggcgc 3060agttcggcga cttcgtcaac ggcgcacagt
cgatcatcga cgagttcatc agctccggtg 3120aggccaagtg gggccaattg
tccaacgtcg tgctgctgtt accgcacggg cacgaggggc 3180agggacccga
ccacacttct gcccggatcg aacgcttctt gcagttgtgg gcggaaggtt
3240cgatgaccat cgcgatgccg tcgactccgt cgaactactt ccacctgcta
cgccggcatg 3300ccctggacgg catccaacgc ccgctgatcg tgttcacgcc
caagtcgatg ttgcgtcaca 3360aggccgccgt cagcgaaatc aaggacttca
ccgagatcaa gttccgctca gtgctggagg 3420aacccaccta tgaggacggc
atcggagacc
gcaacaaggt cagccggatc ctgctgacca 3480gtggcaagct gtattacgag
ctggccgccc gcaaggccaa ggacaaccgc aatgacctcg 3540cgatcgtgcg
gcttgaacag ctcgccccgc tgcccaggcg tcgactgcgt gaaacgctgg
3600accgctacga gaacgtcaag gagttcttct gggtccaaga ggaaccggcc
aaccagggtg 3660cgtggccgcg attcgggctc gaactacccg agctgctgcc
tgacaagttg gccgggatca 3720agcgaatctc gcgccgggcg atgtcagccc
cgtcgtcagg ctcgtcgaag gtgcacgccg 3780tcgaacagca ggagatcctc
gacgaggcgt tcggctaatc tagcaagagg agaagtcgac 3840atgaagttat
taaaattggc acctgatgtt tataaatttg atactgcaga ggagtttatg
3900aaatacttta aggttggaaa aggtgacttt atacttacta atgaattttt
atataaacct 3960ttccttgaga aattcaatga tggtgcagat gctgtatttc
aggagaaata tggactcggt 4020gaaccttctg atgaaatgat aaacaatata
attaaggata ttggagataa acaatataat 4080agaattattg ctgtaggggg
aggatctgta atagatatag ccaaaatcct cagtcttaag 4140tatactgatg
attcattgga tttgtttgag ggaaaagtac ctcttgtaaa aaacaaagaa
4200ttaattatag ttccaactac atgtggaaca ggttcagaag ttacaaatgt
atcagttgca 4260gaattaaaga gaagacatac taaaaaagga attgcttcag
acgaattata tgcaacttat 4320gcagtacttg taccagaatt tataaaagga
cttccatata agttttttgt aaccagctcc 4380gtagatgcct taatacatgc
aacagaagct tatgtatctc caaatgcaaa tccttatact 4440gatatgttta
gtgtaaaagc tatggagtta attttaaatg gatacatgca aatggtagag
4500aaaggaaatg attacagagt tgaaataatt gaggattttg ttataggcag
caattatgca 4560ggtatagctt ttggaaatgc aggagtggga gcggttcacg
cactctcata tccaataggc 4620ggaaattatc atgtgcctca tggagaagca
aattatctgt tttttacaga aatatttaaa 4680acttattatg agaaaaatcc
aaatggcaag attaaagatg taaataaact attagcaggc 4740atactaaaat
gtgatgaaag tgaagcttat gacagtttat cacaactttt agataaatta
4800ttgtcaagaa aaccattaag agaatatgga atgaaagagg aagaaattga
aacttttgct 4860gattcagtaa tagaaggaca gcagagactg ttggtaaaca
attatgaacc tttttcaaga 4920gaagacatag taaacacata taaaaagtta
tattaatcta gaaagcttcc tagaggcatc 4980aaataaaacg aaaggctcag
tcgaaagact gggcctttcg ttttatctgt tgtttgtcgg 5040tgaacgctct
cctgagtagg acaaatccgc cgccctagac cta 5083895097DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
89tctgtatcag gctgaaaatc ttctctcatc cgccaaaaca gcttcggcgt taagatgcgc
60gctcaaggac gtaagccgtc gactctcgcc gtgctggcgc aggacacggc taccactcct
120ttctctgttg atattctgct tgccattgag caaaccgcca gcgagttcgg
ctggaatagt 180tttttaatca atattttttc tgaagatgac gctgcccgcg
cggcacgtca gctgcttgcc 240caccgtccgg atggcattat ctatactaca
atggggctgc gacatatcac gctgcctgag 300tctctgtatg gtgaaaatat
tgtattggcg aactgtgtgg cggatgaccc agcgttaccc 360agttatatcc
ctgatgatta cactgcacaa tatgaatcaa cacagcattt gctcgcggcg
420ggctatcgtc aaccgttatg cttctggcta ccggaaagtg cgttggcaac
agggtatcgt 480cggcagggat ttgagcaggc ctggcgtgat gctggacgag
atctggctga ggtgaaacaa 540tttcacatgg caacaggtga tgatcactac
accgatctcg caagtttact caatgcccac 600ttcaaaccgg gcaaaccaga
ttttgatgtt ctgatatgtg gtaacgatcg cgcagccttt 660gtggcttatc
aggttcttct ggcgaagggg gtacgaatcc cgcaggatgt cgccgtaatg
720ggctttgata atctggttgg cgtcgggcat ctgtttttac cgccgctgac
cacaattcag 780cttccacatg acattatcgg gcgggaagct gcattgcata
ttattgaagg tcgtgaaggg 840ggaagagtga cgcggatccc ttgcccgctg
ttgatccgtt gttccacctg atattatgtt 900aacccagtag ccagagtgct
ccatgttgca gcacagccac tccgtgggag gcataaagcg 960acagttcccg
ttcttctggc tgcggataga ttcgactact catcaccgct tccccgtcgt
1020taataaatac ttccacggat gatgtatcga taaatatcct tagggcgagc
gtgtcacgct 1080gcgggagggg aatactacgg tagccgtcta aattctcgtg
tgggtaatac cgccacaaaa 1140caagtcgctc agattggtta tcaatataca
gccgcattcc agtgccgagc tgtaatccgt 1200aatgttcggc atcactgttc
ttcagcgccc actgcaactg aatctcaact gcttgcgcgt 1260tttcctgcaa
aacatattta ttgctgattg tgcggggaga gacagattga tgctgctggc
1320gtaacgactc agcttcgtgt accgggcgtt gtagaagttt gccattgctc
tctgatagct 1380cgcgcgccag cgtcatgcag cctgcccatc cttcacgttt
tgagggcatt ggcgattccc 1440acatatccat ccagccgata acaatacgcc
gaccatcctt cgctaaaaag ctttgtggtg 1500cataaaagtc atgcccgtta
tcaagttcag taaaatgccc ggattgtgca aaaagtcgtc 1560ctggcgacca
cattccgggt attacgccac tttgaaagcg atttcggtaa ctgtatccct
1620cggcattcat tccctgcggg gaaaacatca gataatgctg atcgccaagg
ctgaaaaagt 1680ccggacattc ccacatatag ctttcacccg catcagcgtg
ggccagtacg cgatcgaagg 1740tccattcacg caacgaactg ccgcgataaa
gcaggatctg ccccgtgttg cctggatctt 1800tcgccccgac taccatccac
catgtgtcgg cttcacgcca cactttagga tcgcggaagt 1860gcatgattcc
ttctggtgga gtgaggatca caccctgttt ctcgaaatga ataccatccc
1920gactggtagc cagacattgt acttcgcgaa ttgcatcgtc attacctgca
ccatcgagcc 1980agacgtgtcc ggtgtagata agtgagagga caccattgtc
atcgacagca ctacctgaaa 2040aacacccgtc tttgtcatta tcgtctcctg
gcgctagcgc aataggctca tgctgccagt 2100ggatcatatc gtcgctggtg
gcatgtcccc agtgcattgg cccccagtgt tcgctcatcg 2160gatgatgttg
ataaaacgcg tgataacgat cgttaaacca gatcaggccg tttggatcgt
2220tcatccaccc ggcaggaggc gcgaggtgaa aatggggata gaaagtgtta
ccccggtgct 2280catgaagttt tgctagggcg ttttgcgccg catgcaatcg
agattgcgtc attttaatca 2340tcctggttaa gcaaatttgg tgaattgtta
acgttaactt ttataaaaat aaagtccctt 2400actttcataa atgcgatgaa
tatcacaaat gttaacgtta actatgacgt tttgtgatcg 2460aatatgcatg
ttttagtaaa tccatgacga ttttgcgaaa aagaggttta tcactatgcg
2520taactcagat gaatttaagg gaaaaaaatg tcagccaaag tatgggtttt
aggggatgcg 2580gtcgtagatc tcttgccaga atcagacggg cgcctactgc
cttgtcctgg cggcgcgcca 2640gctaacgttg cggtgggaat cgccagatta
ggcggaacaa gtgggtttat aggtcgggtg 2700ggggatgatc cttttggtgc
gttaatgcaa agaacgctgc taactgaggg agtcgatatc 2760acgtatctga
agcaagatga atggcaccgg acatccacgg tgcttgtcga tctgaacgat
2820caaggggaac gttcatttac gtttatggtc cgccccagtg ccgatctttt
tttagagacg 2880acagacttgc cctgctggcg acatggcgaa tggttacatc
tctgttcaat tgcgttgtct 2940gccgagcctt cgcgtaccag cgcatttact
gcgatgacgg cgatccggca tgccggaggt 3000tttgtcagct tcgatcctaa
tattcgtgaa gatctatggc aagacgagca tttgctccgc 3060ttgtgtttgc
ggcaggcgct acaactggcg gatgtcgtca agctctcgga agaagaatgg
3120cgacttatca gtggaaaaac acagaacgat caggatatat gcgccctggc
aaaagagtat 3180gagatcgcca tgctgttggt gactaaaggt gcagaagggg
tggtggtctg ttatcgagga 3240caagttcacc attttgctgg aatgtctgtg
aattgtgtcg atagcacggg ggcgggagat 3300gcgttcgttg ccgggttact
cacaggtctg tcctctacgg gattatctac agatgagaga 3360gaaatgcgac
gaattatcga tctcgctcaa cgttgcggag cgcttgcagt aacggcgaaa
3420ggggcaatga cagcgctgcc atgtcgacaa gaactggaat agtgagaagt
aaacggcgaa 3480gtcgctctta tctctaaata ggacgtgaat tttttaacga
caggcaggta attatggcac 3540tgaatattcc attcagaaat gcgtactatc
gttttgcatc cagttactca tttctctttt 3600ttatttcctg gtcgctgtgg
tggtcgttat acgctatttg gctgaaagga catctagggt 3660tgacagggac
ggaattaggt acactttatt cggtcaacca gtttaccagc attctattta
3720tgatgttcta cggcatcgtt caggataaac tcggtctgaa gaaaccgctc
atctggtgta 3780tgagtttcat cctggtcttg accggaccgt ttatgattta
cgtttatgaa ccgttactgc 3840aaagcaattt ttctgtaggt ctaattctgg
gggcgctatt ttttggcttg gggtatctgg 3900cgggatgcgg tttgcttgat
agcttcaccg aaaaaatggc gcgaaatttt catttcgaat 3960atggaacagc
gcgcgcctgg ggatcttttg gctatgctat tggcgcgttc tttgccggca
4020tattttttag tatcagtccc catatcaact tctggttggt ctcgctattt
ggcgctgtat 4080ttatgatgat caacatgcgt tttaaagata aggatcacca
gtgcgtagcg gcagatgcgg 4140gaggggtaaa aaaagaggat tttatcgcag
ttttcaagga tcgaaacttc tgggttttcg 4200tcatatttat tgtggggacg
tggtctttct ataacatttt tgatcaacaa ctttttcctg 4260tcttttattc
aggtttattc gaatcacacg atgtaggaac gcgcctgtat ggttatctca
4320actcattcca ggtggtactc gaagcgctgt gcatggcgat tattcctttc
tttgtgaatc 4380gggtagggcc aaaaaatgca ttacttatcg gagttgtgat
tatggcgttg cgtatccttt 4440cctgcgcgct gttcgttaac ccctggatta
tttcattagt gaagttgtta catgccattg 4500aggttccact ttgtgtcata
tccgtcttca aatacagcgt ggcaaacttt gataagcgcc 4560tgtcgtcgac
gatctttctg attggttttc aaattgccag ttcgcttggg attgtgctgc
4620tttcaacgcc gactgggata ctctttgacc acgcaggcta ccagacagtt
ttcttcgcaa 4680tttcgggtat tgtctgcctg atgttgctat ttggcatttt
cttcttgagt aaaaaacgcg 4740agcaaatagt tatggaaacg cctgtacctt
cagcaatata gacgtaaact ttttccggtt 4800gttgtcgata gctctatatc
cctcaaccgg aaaataataa tagtaaaatg cttagccctg 4860ctaataatcg
cctaatccaa acgcctcatt catgttctgg tacagtcgct caaatgtact
4920tcagatgcgc ggttcgctga tttccaggac attgtcgtca ttcagtgacc
tgtcccgtgt 4980atcacggtcc tgcgaattca tcaaggaatg cattgcggag
tgaagtatcg agtcacgcca 5040tatttcgtca cccgaagatg agttttgaga
tattaaggca ggtgactttc actcaca 5097903525DNANocardia iowensis
90atggcagtgg attcaccgga tgagcggcta cagcgccgca ttgcacagtt gtttgcagaa
60gatgagcagg tcaaggccgc acgtccgctc gaagcggtga gcgcggcggt gagcgcgccc
120ggtatgcggc tggcgcagat cgccgccact gttatggcgg gttacgccga
ccgcccggcc 180gccgggcagc gtgcgttcga actgaacacc gacgacgcga
cgggccgcac ctcgctgcgg 240ttacttcccc gattcgagac catcacctat
cgcgaactgt ggcagcgagt cggcgaggtt 300gccgcggcct ggcatcatga
tcccgagaac cccttgcgcg caggtgattt cgtcgccctg 360ctcggcttca
ccagcatcga ctacgccacc ctcgacctgg ccgatatcca cctcggcgcg
420gttaccgtgc cgttgcaggc cagcgcggcg gtgtcccagc tgatcgctat
cctcaccgag 480acttcgccgc ggctgctcgc ctcgaccccg gagcacctcg
atgcggcggt cgagtgccta 540ctcgcgggca ccacaccgga acgactggtg
gtcttcgact accaccccga ggacgacgac 600cagcgtgcgg ccttcgaatc
cgcccgccgc cgccttgccg acgcgggcag cttggtgatc 660gtcgaaacgc
tcgatgccgt gcgtgcccgg ggccgcgact taccggccgc gccactgttc
720gttcccgaca ccgacgacga cccgctggcc ctgctgatct acacctccgg
cagcaccgga 780acgccgaagg gcgcgatgta caccaatcgg ttggccgcca
cgatgtggca ggggaactcg 840atgctgcagg ggaactcgca acgggtcggg
atcaatctca actacatgcc gatgagccac 900atcgccggtc gcatatcgct
gttcggcgtg ctcgctcgcg gtggcaccgc atacttcgcg 960gccaagagcg
acatgtcgac actgttcgaa gacatcggct tggtacgtcc caccgagatc
1020ttcttcgtcc cgcgcgtgtg cgacatggtc ttccagcgct atcagagcga
gctggaccgg 1080cgctcggtgg cgggcgccga cctggacacg ctcgatcggg
aagtgaaagc cgacctccgg 1140cagaactacc tcggtgggcg cttcctggtg
gcggtcgtcg gcagcgcgcc gctggccgcg 1200gagatgaaga cgttcatgga
gtccgtcctc gatctgccac tgcacgacgg gtacgggtcg 1260accgaggcgg
gcgcaagcgt gctgctcgac aaccagatcc agcggccgcc ggtgctcgat
1320tacaagctcg tcgacgtgcc cgaactgggt tacttccgca ccgaccggcc
gcatccgcgc 1380ggtgagctgt tgttgaaggc ggagaccacg attccgggct
actacaagcg gcccgaggtc 1440accgcggaga tcttcgacga ggacggcttc
tacaagaccg gcgatatcgt ggccgagctc 1500gagcacgatc ggctggtcta
tgtcgaccgt cgcaacaatg tgctcaaact gtcgcagggc 1560gagttcgtga
ccgtcgccca tctcgaggcc gtgttcgcca gcagcccgct gatccggcag
1620atcttcatct acggcagcag cgaacgttcc tatctgctcg cggtgatcgt
ccccaccgac 1680gacgcgctgc gcggccgcga caccgccacc ttgaaatcgg
cactggccga atcgattcag 1740cgcatcgcca aggacgcgaa cctgcagccc
tacgagattc cgcgcgattt cctgatcgag 1800accgagccgt tcaccatcgc
caacggactg ctctccggca tcgcgaagct gctgcgcccc 1860aatctgaagg
aacgctacgg cgctcagctg gagcagatgt acaccgatct cgcgacaggc
1920caggccgatg agctgctcgc cctgcgccgc gaagccgccg acctgccggt
gctcgaaacc 1980gtcagccggg cagcgaaagc gatgctcggc gtcgcctccg
ccgatatgcg tcccgacgcg 2040cacttcaccg acctgggcgg cgattccctt
tccgcgctgt cgttctcgaa cctgctgcac 2100gagatcttcg gggtcgaggt
gccggtgggt gtcgtcgtca gcccggcgaa cgagctgcgc 2160gatctggcga
attacattga ggcggaacgc aactcgggcg cgaagcgtcc caccttcacc
2220tcggtgcacg gcggcggttc cgagatccgc gccgccgatc tgaccctcga
caagttcatc 2280gatgcccgca ccctggccgc cgccgacagc attccgcacg
cgccggtgcc agcgcagacg 2340gtgctgctga ccggcgcgaa cggctacctc
ggccggttcc tgtgcctgga atggctggag 2400cggctggaca agacgggtgg
cacgctgatc tgcgtcgtgc gcggtagtga cgcggccgcg 2460gcccgtaaac
ggctggactc ggcgttcgac agcggcgatc ccggcctgct cgagcactac
2520cagcaactgg ccgcacggac cctggaagtc ctcgccggtg atatcggcga
cccgaatctc 2580ggtctggacg acgcgacttg gcagcggttg gccgaaaccg
tcgacctgat cgtccatccc 2640gccgcgttgg tcaaccacgt ccttccctac
acccagctgt tcggccccaa tgtcgtcggc 2700accgccgaaa tcgtccggtt
ggcgatcacg gcgcggcgca agccggtcac ctacctgtcg 2760accgtcggag
tggccgacca ggtcgacccg gcggagtatc aggaggacag cgacgtccgc
2820gagatgagcg cggtgcgcgt cgtgcgcgag agttacgcca acggctacgg
caacagcaag 2880tgggcggggg aggtcctgct gcgcgaagca cacgatctgt
gtggcttgcc ggtcgcggtg 2940ttccgttcgg acatgatcct ggcgcacagc
cggtacgcgg gtcagctcaa cgtccaggac 3000gtgttcaccc ggctgatcct
cagcctggtc gccaccggca tcgcgccgta ctcgttctac 3060cgaaccgacg
cggacggcaa ccggcagcgg gcccactatg acggcttgcc ggcggacttc
3120acggcggcgg cgatcaccgc gctcggcatc caagccaccg aaggcttccg
gacctacgac 3180gtgctcaatc cgtacgacga tggcatctcc ctcgatgaat
tcgtcgactg gctcgtcgaa 3240tccggccacc cgatccagcg catcaccgac
tacagcgact ggttccaccg tttcgagacg 3300gcgatccgcg cgctgccgga
aaagcaacgc caggcctcgg tgctgccgtt gctggacgcc 3360taccgcaacc
cctgcccggc ggtccgcggc gcgatactcc cggccaagga gttccaagcg
3420gcggtgcaaa cagccaaaat cggtccggaa caggacatcc cgcatttgtc
cgcgccactg 3480atcgataagt acgtcagcga tctggaactg cttcagctgc tctaa
3525911174PRTNocardia iowensis 91Met Ala Val Asp Ser Pro Asp Glu
Arg Leu Gln Arg Arg Ile Ala Gln 1 5 10 15 Leu Phe Ala Glu Asp Glu
Gln Val Lys Ala Ala Arg Pro Leu Glu Ala 20 25 30 Val Ser Ala Ala
Val Ser Ala Pro Gly Met Arg Leu Ala Gln Ile Ala 35 40 45 Ala Thr
Val Met Ala Gly Tyr Ala Asp Arg Pro Ala Ala Gly Gln Arg 50 55 60
Ala Phe Glu Leu Asn Thr Asp Asp Ala Thr Gly Arg Thr Ser Leu Arg 65
70 75 80 Leu Leu Pro Arg Phe Glu Thr Ile Thr Tyr Arg Glu Leu Trp
Gln Arg 85 90 95 Val Gly Glu Val Ala Ala Ala Trp His His Asp Pro
Glu Asn Pro Leu 100 105 110 Arg Ala Gly Asp Phe Val Ala Leu Leu Gly
Phe Thr Ser Ile Asp Tyr 115 120 125 Ala Thr Leu Asp Leu Ala Asp Ile
His Leu Gly Ala Val Thr Val Pro 130 135 140 Leu Gln Ala Ser Ala Ala
Val Ser Gln Leu Ile Ala Ile Leu Thr Glu 145 150 155 160 Thr Ser Pro
Arg Leu Leu Ala Ser Thr Pro Glu His Leu Asp Ala Ala 165 170 175 Val
Glu Cys Leu Leu Ala Gly Thr Thr Pro Glu Arg Leu Val Val Phe 180 185
190 Asp Tyr His Pro Glu Asp Asp Asp Gln Arg Ala Ala Phe Glu Ser Ala
195 200 205 Arg Arg Arg Leu Ala Asp Ala Gly Ser Leu Val Ile Val Glu
Thr Leu 210 215 220 Asp Ala Val Arg Ala Arg Gly Arg Asp Leu Pro Ala
Ala Pro Leu Phe 225 230 235 240 Val Pro Asp Thr Asp Asp Asp Pro Leu
Ala Leu Leu Ile Tyr Thr Ser 245 250 255 Gly Ser Thr Gly Thr Pro Lys
Gly Ala Met Tyr Thr Asn Arg Leu Ala 260 265 270 Ala Thr Met Trp Gln
Gly Asn Ser Met Leu Gln Gly Asn Ser Gln Arg 275 280 285 Val Gly Ile
Asn Leu Asn Tyr Met Pro Met Ser His Ile Ala Gly Arg 290 295 300 Ile
Ser Leu Phe Gly Val Leu Ala Arg Gly Gly Thr Ala Tyr Phe Ala 305 310
315 320 Ala Lys Ser Asp Met Ser Thr Leu Phe Glu Asp Ile Gly Leu Val
Arg 325 330 335 Pro Thr Glu Ile Phe Phe Val Pro Arg Val Cys Asp Met
Val Phe Gln 340 345 350 Arg Tyr Gln Ser Glu Leu Asp Arg Arg Ser Val
Ala Gly Ala Asp Leu 355 360 365 Asp Thr Leu Asp Arg Glu Val Lys Ala
Asp Leu Arg Gln Asn Tyr Leu 370 375 380 Gly Gly Arg Phe Leu Val Ala
Val Val Gly Ser Ala Pro Leu Ala Ala 385 390 395 400 Glu Met Lys Thr
Phe Met Glu Ser Val Leu Asp Leu Pro Leu His Asp 405 410 415 Gly Tyr
Gly Ser Thr Glu Ala Gly Ala Ser Val Leu Leu Asp Asn Gln 420 425 430
Ile Gln Arg Pro Pro Val Leu Asp Tyr Lys Leu Val Asp Val Pro Glu 435
440 445 Leu Gly Tyr Phe Arg Thr Asp Arg Pro His Pro Arg Gly Glu Leu
Leu 450 455 460 Leu Lys Ala Glu Thr Thr Ile Pro Gly Tyr Tyr Lys Arg
Pro Glu Val 465 470 475 480 Thr Ala Glu Ile Phe Asp Glu Asp Gly Phe
Tyr Lys Thr Gly Asp Ile 485 490 495 Val Ala Glu Leu Glu His Asp Arg
Leu Val Tyr Val Asp Arg Arg Asn 500 505 510 Asn Val Leu Lys Leu Ser
Gln Gly Glu Phe Val Thr Val Ala His Leu 515 520 525 Glu Ala Val Phe
Ala Ser Ser Pro Leu Ile Arg Gln Ile Phe Ile Tyr 530 535 540 Gly Ser
Ser Glu Arg Ser Tyr Leu Leu Ala Val Ile Val Pro Thr Asp 545 550 555
560 Asp Ala Leu Arg Gly Arg Asp Thr Ala Thr Leu Lys Ser Ala Leu Ala
565 570 575 Glu Ser Ile Gln Arg Ile Ala Lys Asp Ala Asn Leu Gln Pro
Tyr Glu 580 585 590 Ile Pro Arg Asp Phe Leu Ile Glu Thr Glu Pro Phe
Thr Ile Ala Asn 595 600 605 Gly Leu Leu Ser Gly Ile Ala Lys Leu Leu
Arg Pro Asn Leu Lys Glu 610 615 620 Arg Tyr Gly Ala Gln Leu Glu Gln
Met Tyr Thr Asp Leu Ala Thr Gly 625 630 635 640 Gln Ala Asp Glu Leu
Leu Ala Leu Arg Arg Glu Ala Ala Asp Leu Pro 645 650 655 Val Leu Glu
Thr Val Ser Arg Ala Ala Lys Ala Met Leu Gly Val Ala 660 665 670 Ser
Ala Asp Met Arg Pro Asp Ala His Phe Thr Asp Leu Gly Gly Asp 675 680
685 Ser Leu Ser Ala Leu Ser Phe Ser Asn Leu Leu His Glu Ile Phe Gly
690 695 700 Val Glu Val Pro Val Gly Val Val
Val Ser Pro Ala Asn Glu Leu Arg 705 710 715 720 Asp Leu Ala Asn Tyr
Ile Glu Ala Glu Arg Asn Ser Gly Ala Lys Arg 725 730 735 Pro Thr Phe
Thr Ser Val His Gly Gly Gly Ser Glu Ile Arg Ala Ala 740 745 750 Asp
Leu Thr Leu Asp Lys Phe Ile Asp Ala Arg Thr Leu Ala Ala Ala 755 760
765 Asp Ser Ile Pro His Ala Pro Val Pro Ala Gln Thr Val Leu Leu Thr
770 775 780 Gly Ala Asn Gly Tyr Leu Gly Arg Phe Leu Cys Leu Glu Trp
Leu Glu 785 790 795 800 Arg Leu Asp Lys Thr Gly Gly Thr Leu Ile Cys
Val Val Arg Gly Ser 805 810 815 Asp Ala Ala Ala Ala Arg Lys Arg Leu
Asp Ser Ala Phe Asp Ser Gly 820 825 830 Asp Pro Gly Leu Leu Glu His
Tyr Gln Gln Leu Ala Ala Arg Thr Leu 835 840 845 Glu Val Leu Ala Gly
Asp Ile Gly Asp Pro Asn Leu Gly Leu Asp Asp 850 855 860 Ala Thr Trp
Gln Arg Leu Ala Glu Thr Val Asp Leu Ile Val His Pro 865 870 875 880
Ala Ala Leu Val Asn His Val Leu Pro Tyr Thr Gln Leu Phe Gly Pro 885
890 895 Asn Val Val Gly Thr Ala Glu Ile Val Arg Leu Ala Ile Thr Ala
Arg 900 905 910 Arg Lys Pro Val Thr Tyr Leu Ser Thr Val Gly Val Ala
Asp Gln Val 915 920 925 Asp Pro Ala Glu Tyr Gln Glu Asp Ser Asp Val
Arg Glu Met Ser Ala 930 935 940 Val Arg Val Val Arg Glu Ser Tyr Ala
Asn Gly Tyr Gly Asn Ser Lys 945 950 955 960 Trp Ala Gly Glu Val Leu
Leu Arg Glu Ala His Asp Leu Cys Gly Leu 965 970 975 Pro Val Ala Val
Phe Arg Ser Asp Met Ile Leu Ala His Ser Arg Tyr 980 985 990 Ala Gly
Gln Leu Asn Val Gln Asp Val Phe Thr Arg Leu Ile Leu Ser 995 1000
1005 Leu Val Ala Thr Gly Ile Ala Pro Tyr Ser Phe Tyr Arg Thr Asp
1010 1015 1020 Ala Asp Gly Asn Arg Gln Arg Ala His Tyr Asp Gly Leu
Pro Ala 1025 1030 1035 Asp Phe Thr Ala Ala Ala Ile Thr Ala Leu Gly
Ile Gln Ala Thr 1040 1045 1050 Glu Gly Phe Arg Thr Tyr Asp Val Leu
Asn Pro Tyr Asp Asp Gly 1055 1060 1065 Ile Ser Leu Asp Glu Phe Val
Asp Trp Leu Val Glu Ser Gly His 1070 1075 1080 Pro Ile Gln Arg Ile
Thr Asp Tyr Ser Asp Trp Phe His Arg Phe 1085 1090 1095 Glu Thr Ala
Ile Arg Ala Leu Pro Glu Lys Gln Arg Gln Ala Ser 1100 1105 1110 Val
Leu Pro Leu Leu Asp Ala Tyr Arg Asn Pro Cys Pro Ala Val 1115 1120
1125 Arg Gly Ala Ile Leu Pro Ala Lys Glu Phe Gln Ala Ala Val Gln
1130 1135 1140 Thr Ala Lys Ile Gly Pro Glu Gln Asp Ile Pro His Leu
Ser Ala 1145 1150 1155 Pro Leu Ile Asp Lys Tyr Val Ser Asp Leu Glu
Leu Leu Gln Leu 1160 1165 1170 Leu 92669DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
92atgattgaaa ccattctgcc tgcaggcgtt gaaagcgcag aactgctgga atatccggaa
60gatctgaaag cacatccggc agaagaacat ctgattgcca aaagcgttga aaaacgtcgt
120cgtgatttta ttggtgcacg tcattgtgca cgtctggcac tggcagaact
gggtgaacct 180ccggttgcaa ttggtaaagg tgaacgtggt gcaccgattt
ggcctcgtgg tgttgttggt 240agcctgaccc attgtgatgg ttatcgtgca
gcagcagttg cacataaaat gcgctttcgc 300agcattggta ttgatgcaga
accgcatgca accctgccgg aaggtgttct ggatagcgtt 360agcctgccgc
cggaacgtga atggctgaaa accaccgata gcgcactgca tctggatcgt
420ctgctgtttt gtgcaaaaga agccacctat aaagcctggt ggccgctgac
agcacgttgg 480ctgggttttg aagaagccca tattaccttt gaaattgaag
atggtagcgc agatagcggt 540aatggcacct ttcatagcga actgctggtt
ccgggtcaga ccaatgatgg tggtacaccg 600ctgctgagct ttgatggtcg
ttggctgatt gcagatggtt ttattctgac cgcaattgcc 660tatgcctaa
66993222PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 93Met Ile Glu Thr Ile Leu Pro Ala Gly Val Glu
Ser Ala Glu Leu Leu 1 5 10 15 Glu Tyr Pro Glu Asp Leu Lys Ala His
Pro Ala Glu Glu His Leu Ile 20 25 30 Ala Lys Ser Val Glu Lys Arg
Arg Arg Asp Phe Ile Gly Ala Arg His 35 40 45 Cys Ala Arg Leu Ala
Leu Ala Glu Leu Gly Glu Pro Pro Val Ala Ile 50 55 60 Gly Lys Gly
Glu Arg Gly Ala Pro Ile Trp Pro Arg Gly Val Val Gly 65 70 75 80 Ser
Leu Thr His Cys Asp Gly Tyr Arg Ala Ala Ala Val Ala His Lys 85 90
95 Met Arg Phe Arg Ser Ile Gly Ile Asp Ala Glu Pro His Ala Thr Leu
100 105 110 Pro Glu Gly Val Leu Asp Ser Val Ser Leu Pro Pro Glu Arg
Glu Trp 115 120 125 Leu Lys Thr Thr Asp Ser Ala Leu His Leu Asp Arg
Leu Leu Phe Cys 130 135 140 Ala Lys Glu Ala Thr Tyr Lys Ala Trp Trp
Pro Leu Thr Ala Arg Trp 145 150 155 160 Leu Gly Phe Glu Glu Ala His
Ile Thr Phe Glu Ile Glu Asp Gly Ser 165 170 175 Ala Asp Ser Gly Asn
Gly Thr Phe His Ser Glu Leu Leu Val Pro Gly 180 185 190 Gln Thr Asn
Asp Gly Gly Thr Pro Leu Leu Ser Phe Asp Gly Arg Trp 195 200 205 Leu
Ile Ala Asp Gly Phe Ile Leu Thr Ala Ile Ala Tyr Ala 210 215 220
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