U.S. patent application number 10/368770 was filed with the patent office on 2003-12-04 for novel spinosyn-producing polyketide synthases.
Invention is credited to Burns, Lesley S., Graupner, Paul R., Lewer, Paul, Martin, Christine J., Vousden, William A., Waldron, Clive, Wilkinson, Barrie.
Application Number | 20030225006 10/368770 |
Document ID | / |
Family ID | 27757699 |
Filed Date | 2003-12-04 |
United States Patent
Application |
20030225006 |
Kind Code |
A1 |
Burns, Lesley S. ; et
al. |
December 4, 2003 |
Novel spinosyn-producing polyketide synthases
Abstract
The invention provides, biologically active spinosyns, hybrid
spinosyn polyketide synthases capable of functioning in
Saccharopolyspora spinosa to produce the spinosyns, and methods of
controlling insects using the spinosyns.
Inventors: |
Burns, Lesley S.;
(Cambridge, GB) ; Graupner, Paul R.; (Carmel,
IN) ; Lewer, Paul; (Indianapolis, IN) ;
Martin, Christine J.; (Cambridge, GB) ; Vousden,
William A.; (Dry Drayton, GB) ; Waldron, Clive;
(Indianapolis, IN) ; Wilkinson, Barrie;
(Sharnbrook, GB) |
Correspondence
Address: |
DOW AGROSCIENCES LLC
9330 ZIONSVILLE RD
INDIANAPOLIS
IN
46268
US
|
Family ID: |
27757699 |
Appl. No.: |
10/368770 |
Filed: |
February 19, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60358075 |
Feb 19, 2002 |
|
|
|
Current U.S.
Class: |
514/28 ;
536/7.1 |
Current CPC
Class: |
A01N 43/22 20130101;
C07H 17/08 20130101; C07H 15/26 20130101; C12P 19/62 20130101; C12N
15/52 20130101 |
Class at
Publication: |
514/28 ;
536/7.1 |
International
Class: |
A61K 031/7048; C07H
017/08 |
Claims
1. A compound of the formula (I) 12wherein R1 is hydrogen, methyl,
or ethyl; R2 is hydrogen, methyl, or ethyl; R3 is hydrogen, 13R4 is
methyl or ethyl, either of which may be substituted with one or
more groups selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl,
C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; R4 is
an alpha-branched C.sub.3-C.sub.5 alkyl group, C.sub.3-C.sub.8
cycloalkyl group, or C.sub.3-C.sub.8 cycloalkenyl group, any of
which may be substituted with one or more groups selected from
halo, hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy,
C.sub.1-C.sub.4 alkylthio, or cyano; or R4 is a 3-6 membered
heterocyclic group that contains O or S, that is saturated or fully
or partially unsaturated, and that may be substituted with one or
more groups selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl,
C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; R5 is
hydrogen or methyl; R6 is hydrogen or methyl; R7 is hydrogen or
methyl; R8 is hydrogen, methyl, or ethyl; R9 is hydrogen, methyl,
or ethyl; or a 5,6-dihydro derivative of a compound of formula I,
provided that the compound has at least one of the following
features: a) R4 is methyl or ethyl substituted with one or more
groups selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl,
C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or b)
R4 is an alpha-branched C.sub.3-C.sub.5 alkyl group,
C.sub.3-C.sub.8 cycloalkyl group, or C.sub.3-C.sub.8 cycloalkenyl
group, any of which may be substituted with one or more groups
selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4
alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or c) R4 is a 3-6
membered heterocyclic group that contains O or S, that is saturated
or fully or partially unsaturated, and that may be substituted with
one or more groups selected from halo, hydroxy, C.sub.1-C.sub.4
alkyl, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano;
or d) R1 or R2 is ethyl; or e) R8 is methyl or ethyl; or f) R9 is
methyl or ethyl.
2. A compound of claim 1 wherein R1 is ethyl.
3. A compound of claim 1 wherein R2 is ethyl.
4. A compound of claim 1 wherein R4 is methyl or ethyl substituted
with one or more groups selected from halo, hydroxy,
C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4
alkylthio, or cyano; or an alpha-branched C.sub.3-C.sub.5 alkyl
group, C.sub.3-C.sub.8 cycloalkyl group, or C.sub.3-C.sub.8
cycloalkenyl group, any of which may be substituted with one or
more groups selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl,
C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or a
3-6 membered heterocyclic group that contains O or S, that is
saturated or fully or partially unsaturated, and that may be
substituted with one or more groups selected from halo, hydroxy,
C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4
alkylthio, or cyano.
5. A compound of claim 4 wherein R4 is the residue of a carboxylic
acid useable as a substrate by the ery or ave loading modules.
6. A compound of claim 4 wherein R4 is n-propyl, iso-propyl,
cyclopropyl, methylcyclopropyl, sec-butyl, cyclobutyl, methylthio,
or furyl.
7. A compound selected from the group consisting of:
21-desethyl-21-cyclopropyl spinosyn A; 21-desethyl-21-cyclopropyl
spinosyn D; 21-desethyl-21-cyclobutyl spinosyn A;
21-desethyl-21-cyclobut- yl spinosyn D;
21-desethyl-21-methylthiomethyl spinosyn A;
21-desethyl-21-methylthiomethyl spinosyn D;
21-desethyl-21-cyanomethyl spinosyn A;
5,6-dihydro-21-desethyl-21-cyclobutyl spinosyn A;
21-desethyl-21-isopropyl spinosyn A; 21-desethyl-21-isopropyl
spinosyn D; 21-desethyl-21-sec-butyl spinosyn A;
21-desethyl-21-sec-butyl spinosyn D;
21-desethyl-21-methylcyclopropyl spinosyn A;
21-desethyl-21-methylcyclopr- opyl spinosyn D;
21-desethyl-21-(3-furyl) spinosyn A; 21-desethyl-21-(3-furyl)
spinosyn D; 21-desethyl-21-cyclopropyl spinosyn A
17-pseudoaglycone; 21-desethyl-21-cyclopropyl spinosyn D
17-pseudoaglycone; 21-desethyl-21-cyclobutyl spinosyn A
17-pseudoaglycone; 21-desethyl-21-cyclobutyl spinosyn D
17-pseudoaglycone; 16-desmethyl spinosyn D; 16-desmethyl spinosyn D
17-pseudoaglycone; 21-desethyl-21-n-propyl spinosyn A; 6-ethyl
spinosyn A; 6-ethyl-21-desethyl-21-n-propyl spinosyn A;
16-desmethyl-16-ethyl spinosyn A; 16-desmethyl-16-ethyl spinosyn D;
and 21-desethyl-21-n-propyl spinosyn D.
8. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active spinosyn, said hybrid polyketide synthase comprising a
heterologous loading module operatively associated with a plurality
of Saccharopolyspora spinosa extender modules.
9. A hybrid spinosyn polyketide synthase of claim 8 comprising a
loading module of SEQ ID NO:8.
10. A hybrid spinosyn polyketide synthase of claim 8 comprising a
loading module of SEQ ID NO:11.
11. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 16-ethyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA modified so
that the DNA for the AT domain of module 3 in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates ethyl
malonyl-CoA.
12. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 18-ethyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA modified so
that the DNA for the AT domain of module 2 in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates ethyl
malonyl-CoA.
13. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 20-ethyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA modified so
that the DNA for the AT domain of module 1 in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates ethyl
malonyl-CoA.
14. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 16-ethyl spinosyn compound, 20-ethyl spinosyn compound, or
18-ethyl spinosyn compound, said hybrid polyketide synthase being
the product produced by spinosyn biosynthetic DNA modified so that
the DNA for the AT domain of module 3, module 2, or module 1 in the
spinosyn PKS is replaced with DNA for the AT domain of module 5 in
the tylosin PKS.
15. A hybrid spinosyn polyketide synthase of claim 14 wherein said
AT domain is encoded by the DNA of SEQ ID NO:26.
16. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 18-methyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA modified so
that the DNA for the AT domain of module 2 in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates
methyl malonyl-CoA.
17. A hybrid spinosyn polyketide synthase that is capable of
functioning in Saccharopolyspora spinosa to produce a biologically
active 20-methyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA modified so
that the DNA for the AT domain of module 1 in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates
methyl malonyl-CoA.
18. A process for producing a 6-ethyl spinosyn compound, a
21-desethyl-21-n-propyl spinosyn compound, or a
6-ethyl-21-desethyl-21-n-- propyl spinosyn compound which comprises
culturing a host organism that coexpresses crotonyl-CoA reductase
with the spinosyn biosynthetic pathway.
19. The process of claim 18 wherein the host organism is an S.
spinosa strain that has been transformed with DNA encoding the S.
cinnamonensis crotonyl-CoA reductase.
20. An S. spinosa strain that has been transformed with DNA
encoding the S. cinnamonensis crotonyl-CoA reductase.
21. A biologically pure culture of Saccharopolyspora spinosa
selected from NRRL 30539, NRRL 30540, NRRL 30541, and NRRL
30542.
22. A method of controlling pests which comprises delivering to a
pest an effective amount of a compound of claim 1.
23. A pesticide composition comprising an effective amount of a
compound of claim 1 as active ingredient in combination with an
appropriate diluent or carrier
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/358,075, filed Feb. 19, 2002.
SUMMARY OF THE INVENTION
[0002] The present invention provides novel hybrid polyketide
synthases (PKSs), DNA encoding such PKSs, vectors incorporating the
hybrid polyketide synthase DNA, host organisms including but not
limited to Saccharopolyspora spinosa strains transformed with the
hybrid polyketide synthase DNA, methods of using the hybrid
polyketide synthase DNA to change the products made by
spinosyn-producing strains, and the novel biologically-active
compounds generated by these manipulations.
BACKGROUND OF THE INVENTION
[0003] As disclosed in U.S. Pat. No. 5,362,634, fermentation
product A83543 is a family of related compounds produced by
Saccharopolyspora spinosa. The family of natural spinosyn compounds
that have previously been isolated are described in U.S. Pat. No.
6,274,350 B1 and WO 01/19840, along with their activities in a
variety of insect control assays. A number of semi-synthetic
spinosyn analogues are also described in U.S. Pat. No. 6,001,981,
in which the chemically accessible areas of the spinosyn molecule
were successfully substituted in a variety of ways.
[0004] The known members of this family have been referred to as
factors or components, and each has been given an identifying
letter designation. These compounds are hereinafter referred to as
spinosyn A, B, etc. The spinosyn compounds are useful for the
control of arachnids, nematodes and insects, in particular
Lepidoptera and Diptera species, and they are quite environmentally
friendly and have an appealing toxicological profile. The
commercial product Spinosad is a mixture of spinosyns A and D
(Pesticide Manual, 11th ed., p. 1272).
[0005] Tables 1 and 2 identify the structures of some known
spinosyn compounds:
1TABLE 1 1 Factor R1 R2 R3 R4 R5 R6 R7 spinosyn A H CH.sub.3 2
C.sub.2H.sub.5 CH.sub.3 CH.sub.3 CH.sub.3 (a) spinosyn B H CH.sub.3
3 C.sub.2H.sub.5 CH.sub.3 CH.sub.3 CH.sub.3 (b) spinosyn C H
CH.sub.3 4 C.sub.2H.sub.5 CH.sub.3 CH.sub.3 CH.sub.3 (c) spinosyn D
CH.sub.3 CH.sub.3 (a) C.sub.2H.sub.5 CH.sub.3 CH.sub.3 CH.sub.3
spinosyn E H CH.sub.3 (a) CH.sub.3 CH.sub.3 CH.sub.3 CH.sub.3
spinosyn F H H (a) C.sub.2H.sub.5 CH.sub.3 CH.sub.3 CH.sub.3
spinosyn A 17-Psa H CH.sub.3 H C.sub.2H.sub.5 CH.sub.3 CH.sub.3
CH.sub.3 spinosyn D 17-Psa CH.sub.3 CH.sub.3 H C.sub.2H.sub.5
CH.sub.3 CH.sub.3 CH.sub.3 spinosyn E 17-Psa H CH.sub.3 H CH.sub.3
CH.sub.3 CH.sub.3 CH.sub.3
[0006]
2TABLE 2 5 Factor R1 R2 R3 R4 R5 spinosyn A 9-Psa H CH.sub.3 6
C.sub.2H.sub.5 H (a) spinosyn D 9-Psa CH.sub.3 CH.sub.3 (a)
C.sub.2H.sub.5 H spinosyn A H CH.sub.3 H C.sub.2H.sub.5 H aglycone
spinosyn D CH.sub.3 CH.sub.3 H C.sub.2H.sub.5 H aglycone
[0007] The naturally produced spinosyn compounds consist of a
5,6,5-tricylic ring system, fused to a 12-membered macrocyclic
lactone, a neutral sugar (rhamnose) and an amino sugar (forosamine)
(see Kirst et al. (1991). If the amino sugar is not present the
compounds have been referred to as the pseudoaglycone of A, D,
etc., and if the neutral sugar is not present then the compounds
have been referred to as the reverse pseudoaglycone of A, D, etc. A
more preferred nomenclature is to refer to the pseudoaglycones as
spinosyn A 17-Psa, spinosyn D 17-Psa, etc., and to the reverse
pseudoaglycones as spinosyn A 9-Psa, spinosyn D 9-Psa, etc.
[0008] The naturally produced spinosyn compounds may be produced
via fermentation from cultures NRRL 18395, 18537, 18538, 18539,
18719, 18720, 18743 and 18823. These cultures have been deposited
and made part of the stock culture collection of the Midwest Area
Northern Regional Research Center, Agricultural Research Service,
United States Department of Agriculture, 1815 North University
Street, Peoria, Ill. 61604.
[0009] U.S. Pat. No. 5,362,634 and corresponding European Patent
Application No. 375316 A1 disclose spinosyns A, B, C, D, E, F, G,
H, and J. These compounds are disclosed as being produced by
culturing a strain of the novel microorganism Saccharopolyspora
spinosa selected from NRRL 18395, NRL 18537, NRRL 18538, and NRRL
18539.
[0010] WO 93/09126 disclosed spinosyns L, M, N, Q, R, S, and T.
Also disclosed therein are two spinosyn J producing strains: NRRL
18719 and NRRL 18720, and a strain that produces spinosyns Q, R, S,
and T: NRRL 18823.
[0011] WO 94/20518 and U.S. Pat. No. 5,670,486 disclose spinosyns
K, O, P, U, V, W, and Y, and derivatives thereof. Also disclosed is
spinosyn K-producing strain NRRL 18743.
[0012] WO 01/19840 discloses spinosyn analogs produced by culturing
Saccharopolyspora species LW107129 (NRRL 30141).
[0013] WO 99/46387 and U.S. Pat. No. 6,143,526 disclose the
spinosyn biosynthetic genes from Saccharopolyspora spinosa.
[0014] The nature of the genes involved in spinosyn biosynthesis,
together with previous studies of precursor incorporation
(Broughton et al., 1991), indicate that spinosyns are produced by
the stepwise condensation of 2-carbon and 3-carbon carboxylic acids
to generate a polyketide that is cyclized and bridged. The
tetracyclic, aglycone product of these reactions is converted to
the pseudoaglycone by addition of a rhamnosyl residue, and
synthesis is completed by the addition of the di-N-methylated
sugar, forosamine. In some aspects, this process is similar to the
biosynthetic pathway by which other macrolides (such as the
antibiotic erythromycin, the antihelmintic avermectin, and the
immunosuppressant rapamycin) are produced. In particular, the
polyketide nucleus is assembled by a very large, multifunctional
protein that is a Type I polyketide synthase (spn PKS). This
polypeptide complex comprises a loading module and ten extension
modules, each module being responsible for both the addition of a
specific acyl-CoA precursor to the growing polyketide chain, and
for the degree of reduction of the .beta.-keto carbonyl group. Each
module performs several biochemical reactions which are carried out
by specific domains of the polypeptide. All the extension modules
contain an acyl transferase (AT) domain that donates the acyl group
from a precursor to an acyl carrier protein (ACP) domain, and a
.beta.-ketosynthase (KS) domain that adds the pre-existing
polyketide chain to the new acyl-ACP by decarboxylative
condensation. Additional domains are present in some extension
modules: .beta.-ketoreductase (KR) domains reduce .beta.-keto
groups to hydroxyls, dehydratase (DH) domains remove hydroxyls to
leave double bonds, and the enoyl reductase (ER) domain reduces a
double bond to leave a saturated carbon. The loading module of the
spn PKS is different from the extension modules in that it contains
a variant KS domain (KSq), as well as AT and ACP domains. The KSq
domain, which is also found in some other Type I PKS loading
modules (but not all), is believed to provide the requisite starter
unit by decarboxylation of an ACP-bound acyl chain (Bisang et al.,
1999). The terminal extension module contains a
thioesterase/cyclase (TE) domain that liberates the polyketide
chain from the PKS.
[0015] The spinosyn PKS DNA region consists of 5 ORFs with in-frame
stop codons at the end of some ACP domains, similar to the PKS ORFs
in the other macrolide-producing bacteria. The five spinosyn PKS
genes are arranged head-to-tail, without any intervening non-PKS
functions such as the insertion element found between the
erythromycin PKS genes AI and AII (Donadio et al., 1993). They are
designated spna, spnB, spnC, spnD, and spnE. The nucleotide
sequence for each of the five spinosyn PKS genes, and the
corresponding polypeptides, are identified in U.S. Pat. No.
6,143,526 and in Waldron et al., 2001. Also identified in these
sources are the predicted translation products of the PKS genes,
and the boundaries of the domains and modules.
[0016] After it is synthesized, the spinosyn polyketide precursor
condenses to form a macrocyclic lactone, referred to hereinafter as
the polyketide nucleus. Production of insecticidally-active
spinosyns requires additional processing of the polyketide nucleus.
First, carbon-carbon bridges must be formed between C3 and C14, C4
and C12, and C7 and C11, to generate the aglycone intermediate.
Possible mechanisms for these unusual reactions have been suggested
(Waldron et al., 2001), but the structural features of the
polyketide substrate that are required for them to occur are not
known. Second, a tri-O-methyl rhamnose must be incorporated at C9
to generate the pseudoaglycone. It is not known if the rhamnose is
normally methylated before or after its addition to the aglycone,
but S. spinosa is capable of adding the methyl groups after the
rhamnose moiety has been conjugated to the aglycone (Broughton et
al., 1991). The methylations must occur in a particular sequence
(2' then 3' then 4') or not all of them will take place, indicating
that the methyltransferases have very specific substrate
requirements. The third processing step, addition of forosamine at
C17, is needed to produce the most active spinosyns. The enzymes
involved in this step also have stringent substrate requirements:
the forosaminyl transferase will not use the aglycone as a
substrate, and the N-methyltransferase will not act on the
forosamine after it has been attached to the pseudoaglycone. This
substrate-specificity of later biosynthetic enzymes may be a
barrier to producing novel, biologically-active spinosyns from
precursors with different chemical structures.
[0017] In certain cases polyketide synthase (PKS) genes have
previously been manipulated with the objective of providing novel
polyketides. In-frame deletion of the DNA encoding part of the KR
domain in module 5 of the erythromycin-producing (ery) PKS has been
shown to lead to the formation of erythromycin analogues, namely
5,6-dideoxy-3alpha-mycarosyl-- 5-oxoerythronolide B and
5,6-dideoxy-5-oxoerythronolide B (Donadio et al., 1991). Likewise,
alteration of active site residues in the ER domain of module 4 of
the ery PKS, by genetic engineering of the corresponding
PKS-encoding DNA and its introduction into Saccharopolyspora
erythraea, led to the production of 6,7-anhydroerythromycin C
(Donadio et al., 1993). WO 93/13663 describes additional types of
genetic manipulation of the ery PKS genes that are capable of
producing altered polyketides.
[0018] WO 98/01546 discloses replacement of the loading module of
the ery PKS with the loading module from the avermectin (ave) PKS,
to produce a hybrid Type I PKS gene that incorporates different
starter units to make novel erythromycin analogues.
[0019] However, it has also been found that not all manipulations
of PKS genes produce the targeted new analogues. When Donadio et
al. (1993) inactivated an ER domain of the ery PKS, the resulting
anhydro-derivative could not be completely processed because it was
no longer a substrate for the mycarose-O-methyltransferase.
Changing the polyketide starter unit prevented complete elongation
and elaboration of a rifamycin analogue in Amycolatopsis
mediterranei (Hunziker et al., 1998). Given the extensive
substrate-specific processing that is required to generate
insecticidally-active spinosyns, it is not obvious that genetic
modifications which change the structure of a spinosyn polyketide
will permit synthesis of a fully-processed molecule with useful
biological activity. However, if such analogues could be made, and
they had a different spectrum of insecticidal activity, they would
be highly desirable because known spinosyns do not control all
pests.
BRIEF DESCRIPTION OF THE INVENTION
[0020] In one of its aspects, the invention provides a hybrid
spinosyn polyketide synthase that is capable of functioning in
Saccharopolyspora spinosa to produce a biologically active
spinosyn, said hybrid polyketide synthase comprising a heterologous
loading module operatively associated with a plurality of
Saccharopolyspora spinosa extender modules. In preferred
embodiments, the spinosyn loading domain is replaced with the
loading domain for the erythromycin PKS or avermectin PKS. The ave
and ery loading domains are of particular interest because they
accept a variety of starter units. Also useful are hybrid PKS genes
in which the heterologous loading module incorporates an unusual
starter unit, such as the loading module for rapamycin (cyclohexene
carboxylic acid) or for myxathiazole (3-methyl butyric acid). The
required precursors, e.g. cyclohexene carboxylic acid or 3-methyl
butyric acid, may be provided in the culture medium, or the genes
encoding their biosynthetic enzymes may be engineered into the
organism so they are synthesized endogenously.
[0021] In another of its aspects, the invention provides a hybrid
spinosyn polyketide synthase that is capable of functioning in
Saccharopolyspora spinosa to produce a biologically active 6-ethyl
spinosyn compound, 16-ethyl spinosyn compound, 18-ethyl spinosyn
compound, or 20-ethyl spinosyn compound, said hybrid polyketide
synthase being the product produced by spinosyn biosynthetic DNA
that has been modified so that the DNA for the AT domain of module
8, 3, 2, or 1, respectively, in the spinosyn PKS is replaced with
DNA for an AT domain that normally incorporates ethyl malonyl-CoA.
In preferred embodiments, the DNA that encodes the relevant
spinosyn AT domain is replaced with the DNA that encodes the AT
domain of module 5 of the tylosin PKS or module 5 of the monensin
PKS. In preferred embodiments, the Streptomyces cinnamonensis
crotonyl-CoA reductase is co-expressed.
[0022] In another of its aspects, the invention provides a hybrid
spinosyn polyketide synthase that is capable of functioning in
Saccharopolyspora spinosa to produce a biologically active
18-methyl spinosyn compound, or 20-methyl spinosyn compound, said
hybrid polyketide synthase being the product produced by spinosyn
biosynthetic DNA that has been modified so that the DNA for the AT
domain of module 2 or 1, respectively, in the spinosyn PKS is
replaced with DNA for an AT domain that normally incorporates
methyl malonyl-CoA.
[0023] In another of its aspects, the invention provides a hybrid
spinosyn polyketide synthase that is capable of functioning in
Saccharopolyspora spinosa to produce a biologically active
16-desmethyl spinosyn compound, said hybrid polyketide synthase
being the product produced by spinosyn biosynthetic DNA that has
been modified so that the DNA for the AT domain of module 3 in the
spinosyn PKS is replaced with DNA for an AT domain that normally
incorporates malonyl-CoA. In a preferred embodiment the AT domain
of module 3 is replaced with the DNA that encodes the AT domain of
module 2 of the rapamycin PKS
[0024] In another of its aspects, the invention provides a process
for producing a 6-ethyl spinosyn compound, a
21-desethyl-21-n-propyl spinosyn compound, or a
6-ethyl-21-desethyl-21-propyl spinosyn compound which comprises
culturing a transgenic host organism that coexpresses crotonyl-CoA
reductase with the spinosyn biosynthetic pathway. In a preferred
embodiment the host organism is transformed with DNA encoding the
S. cinnamonensis crotonyl-CoA reductase.
[0025] In another of its aspects, the invention provides a
Saccharopolyspora spinosa strain that has been transformed with DNA
encoding the S. cinnamonensis crotonyl-CoA reductase.
[0026] In another of its aspects, the invention provides DNA
encoding a hybrid spinosyn polyketide synthase of the invention, as
described above.
[0027] In another of its aspects, the invention provides a vector
comprising DNA as described above.
[0028] In another of its aspects, the invention provides a host
organism comprising DNA as described above.
[0029] In yet another of its aspects, the invention provides a
compound of the formula (I) 7
[0030] R1 is hydrogen, methyl, or ethyl;
[0031] R2 is hydrogen, methyl, or ethyl;
[0032] R3 is hydrogen, 8
[0033] R4 is methyl or ethyl, either of which may be substituted
with one or more groups selected from halo, hydroxy,
C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4
alkylthio, or cyano;
[0034] R4 is an alpha-branched C.sub.3-C.sub.5 alkyl group,
C.sub.3-C.sub.8 cycloalkyl group, or C.sub.3-C.sub.8 cycloalkenyl
group, any of which may be substituted with one or more groups
selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4
alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or
[0035] R4 is a 3-6 membered heterocyclic group that contains O or
S. that is saturated or fully or partially unsaturated, and that
may be substituted with one or more groups selected from halo,
hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy,
C.sub.1-C.sub.4 alkylthio, or cyano;
[0036] R5 is hydrogen or methyl;
[0037] R6 is hydrogen or methyl;
[0038] R7 is hydrogen or methyl;
[0039] R8 is hydrogen, methyl, or ethyl;
[0040] R9 is hydrogen, methyl, or ethyl;
[0041] or a 5,6-dihydro derivative of a compound of formula I,
provided that:
[0042] a) R4 is methyl or ethyl substituted with one or more groups
selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4
alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or
[0043] b) R4 is an alpha-branched C.sub.3-C.sub.5alkyl group,
C.sub.3-C.sub.8 cycloalkyl group, or C.sub.3-C.sub.8 cycloalkenyl
group, any of which may be substituted with one or more groups
selected from halo, hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4
alkoxy, C.sub.1-C.sub.4 alkylthio, or cyano; or
[0044] c) R4 is a 3-6 membered heterocyclic group that contains O
or S, that is saturated or fully or partially unsaturated, and that
may be substituted with one or more groups selected from halo,
hydroxy, C.sub.1-C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy,
C.sub.1-C.sub.4 alkylthio, or cyano; or
[0045] d) R1 or R2 is ethyl; or
[0046] e) R8 is methyl or ethyl; or
[0047] f) R9 is methyl or ethyl.
[0048] Illustrative compounds provided by the invention are
identified in the following Table 3. Compound numbers cited
hereinafter refer to the compounds identified in Table 3.
3TABLE 3 (I) 9 cmpd no. name R1 R2 R3 R4 R5 R6 R7 R8 R9 1
21-desethyl-21-cyclopropyl spinosyn A H CH.sub.3 10 cyclopropyl
CH.sub.3 CH.sub.3 CH.sub.3 H H (a) 2 21-desethyl-21-cyclopropyl
spmosyn D CH.sub.3 CH.sub.3 (a) cyclopropyl CH.sub.3 CH.sub.3
CH.sub.3 H H 3 21-desethyl-21-cyclobutyl spinosyn A H CH.sub.3 (a)
cyclobutyl CH.sub.3 CH.sub.3 CH.sub.3 H H 4
21-desethyl-21-cyclobutyl spmosyn DGil3 CH.sub.3 (a) cyclobutyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 5 21-desethyl-21-methylthiomethyl
spmosyn A H CH.sub.3 (a) methylthio- CH.sub.3 CH.sub.3 CH.sub.3 H H
methyl 6 21-desethyl-21-methylthiomethyl spinosyn D CH.sub.3
CH.sub.3 (a) methylthio- CH.sub.3 CH.sub.3 CH.sub.3 H H methyl 7
21-desethyl-21-cyanomethyl spinosyn A H CH.sub.3 (a) cyanomethyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 8
5,6-dihydro-21-desethyl-21-cyclobutyl spinosyn A H CH.sub.3 (a)
cyclobutyl CH.sub.3 CH.sub.3 CH.sub.3 H H 9
21-desethyl-21-isopropyl spinosyn A H CH.sub.3 (a) isopropyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 10 21-desethyl-21-isopropyl spinosyn
D CH.sub.3 CH.sub.3 (a) isopropyl CH.sub.3 CH.sub.3 CH.sub.3 H H 11
21-desethyl-21-sec-butyl spinosyn A H CH.sub.3 (a) sec-butyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 12 21-desethyl-21-sec-butyl spinosyn
D CH.sub.3 CH.sub.3 (a) sec-butyl CH.sub.3 CH.sub.3 CH.sub.3 H H 13
21-desethyl-21-methylcyclopropyl spinosyn A H CH.sub.3 (a)
methylcyclo- CH.sub.3 CH.sub.3 CH.sub.3 H H propyl 14
21-desethyl-21-methylcyclopropyl spinosyn D CH.sub.3 CH.sub.3 (a)
methylcyclo- CH.sub.3 CH.sub.3 CH.sub.3 H H propyl 15
21-desethyl-21-(3-furyl) spinosyn A H CH.sub.3 (a) 3-furyl CH.sub.3
CH.sub.3 CH.sub.3 H H 16 21-desethyl-21-(3-furyl) spinosyn D
CH.sub.3 CH.sub.3 (a) 3-furyl CH.sub.3 CH.sub.3 CH.sub.3 H H 17
21-desethyl-21-cyclopropyl spinosyn A 17- H CH.sub.3 H cyclopropyl
CH.sub.3 CH.sub.3 CH.sub.3 H H pseudo- aglycone 18
21-desethyl-21-cyclopropyl spinosyn D 17- CH.sub.3 CH.sub.3 H
cyclopropyl CH.sub.3 CH.sub.3 CH.sub.3 H H pseudo- aglycone 19
21-desethyl-21-cyclobutyl spmosyn A 17- H CH.sub.3 H cyclobutyl
CH.sub.3 CH.sub.3 CH.sub.3 H H pseudo- aglycone 20
21-desethyl-21-cyclobutyl spmosyn D 17- CH.sub.3 CH.sub.3 H
cyclobutyl CH.sub.3 CH.sub.3 CH.sub.3 H H pseudo- aglycone 21
16-desmethyl spinosyn D CH.sub.3 H (a) ethyl CH.sub.3 CH.sub.3
CH.sub.3 H H 22 16-desmethyl spmosyn D 17- CH.sub.3 H H ethyl
CH.sub.3 CH.sub.3 CH.sub.3 H H pseudo- aglycone 23
21-desethyl-21-n-propyl spinosyn A H CH.sub.3 (a) n-propyl CH.sub.3
CH.sub.3 CH.sub.3 H H 24 6-ethyl spinosyn A C.sub.2H.sub.3 CH.sub.3
(a) ethyl CH.sub.3 CH.sub.3 CH.sub.3 H H 25
6-ethyl-21-desethyl-21-n-propyl spinosyn A C.sub.2H.sub.3 CH.sub.3
(a) n-propyl CH.sub.3 CH.sub.3 CH.sub.3 H H 26
16-desmethyl-16-ethyl spinosyn A H C.sub.2H.sub.5 (a) ethyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 27 16-desmethyl-16-ethyl spinosyn D
CH.sub.3 C.sub.2H.sub.3 (a) ethyl CH.sub.3 CH.sub.3 CH.sub.3 H H 28
21-desethyl-21-n-propyl spinosyn D CH.sub.3 CH.sub.3 (a) n-propyl
CH.sub.3 CH.sub.3 CH.sub.3 H H 29
5,6-dihydro-21-desethyl-21-n-propyl spinosyn A H CH.sub.3 (a)
n-propyl CH.sub.3 CH.sub.3 CH.sub.3 H H
[0049] The 5,6-dihydro derivatives of the compounds of Formula
I(e.g. compound 8 in Table 3) are compounds of the Formula II:
11
[0050] wherein R1, R2, R3, R4, R5, R6, R7, R8, and R9 are as
defined for Formula I.
[0051] In another of its aspects, the invention provides a
biologically pure culture of Saccharopolyspora spinosa selected
from
[0052] NRRL 30539,
[0053] NRRL 30540,
[0054] NRRL 30541, and
[0055] NRRL 30542.
[0056] In another of its aspects, the invention provides a method
of controlling pests which comprises delivering to a pest an
effective amount of a compound of claim 1.
[0057] In another of its aspects, the invention provides a
pesticide composition comprising an effective amount of a compound
of claim 1 as active ingredient in combination with an appropriate
diluent or carrier.
BRIEF DESCRIPTION OF THE FIGURES
[0058] FIG. 1 shows the construction of pCJR81.
[0059] FIG. 2 shows the construction of vectors pLSB2 and pLSB3
used for expression of genes in S. spinosa.
[0060] FIG. 3 shows the construction of pLSB62, a vector to
introduce the ery load into the spinosyn pathway.
[0061] FIG. 4 shows the hybrid ery/spn PKS pathway of S. spinosa
13E.
[0062] FIG. 5 shows the construction of pLSB29, a vector to
introduce the ave load into the spinosyn pathway.
[0063] FIG. 6 shows the hybrid ave/spn PKS pathway of S. spinosa
21K2
[0064] FIGS. 7a and 7b show the construction of pALK26,
intermediate plasmid used to generate module 3 AT swap
plasmids.
[0065] FIG. 8 shows the construction of pALK39, a vector used to
introduce the rapAT2 into spinosyn module 3.
[0066] FIG. 9 shows the construction of pALK21, a vector designed
to express the S. cinnamonensis crotonyl-CoA reductase gene in S.
spinosa.
[0067] FIG. 10 shows the construction of pALK36, a vector used to
introduce the tylAT5 into spinosyn module 3.
[0068] FIG. 11 shows the hybrid PKS pathway of strain S. spinosa
7D23.
[0069] FIG. 12 shows the hybrid PKS pathway of strain S. spinosa
36P4.
BRIEF DESCRIPTION OF THE SEQUENCES
[0070] SEQ ID NO:1 is oligo PRIS1.
[0071] SEQ ID NO:2 is oligo PRIS2.
[0072] SEQ ID NO:3 is the DNA sequence of the promoter for
resistance to pristinamycin.
[0073] SEQ ID NO:4 is oligo CR311.
[0074] SEQ ID NO:5 is oligo CR312.
[0075] SEQ ID NO:6 is oligo SP28.
[0076] SEQ ID NO:7 is oligo SP29.
[0077] SEQ ID NO 8: is the fragment of DNA encoding the ery PKS
loading module which was used for cloning, with introduced
restriction enzyme sites at bp 1-6 and bp 1680-1685.
[0078] SEQ ID NO:9 is oligo SP14.
[0079] SEQ ID NO:10 is oligo SP15.
[0080] SEQ ID NO: 11is the fragment of DNA encoding the ave PKS
loading module which was used for cloning, with introduced
restriction enzyme sites at bp 1-6 and bp 1689-1694.
[0081] SEQ ID NO:12 is oligo CR322.
[0082] SEQ ID NO:13 is oligo CR323.
[0083] SEQ ID NO:14 is oligo CR324.
[0084] SEQ ID NO:15 is oligo CR325.
[0085] SEQ ID NO:16 is oligo CR328.
[0086] SEQ ID NO:17 is oligo CR329.
[0087] SEQ ID NO:18 is oligo CR330.
[0088] SEQ ID NO:19 is oligo CR321.
[0089] SEQ ID NO:20 is the fragment of DNA encoding the rap AT2
which was used for cloning, with introduced restriction enzyme
sites at bp 1-6 and bp 832-837.
[0090] SEQ ID NO:21 is oligo CCRMONF.
[0091] SEQ ID NO:22 is oligo CCRMONR.
[0092] SEQ ID NO:23 is the DNA sequence used for expression of the
Streptomyces cinnamonensis crotonyl-CoA reductase, with introduced
restriction sites at bp 1-6 and 1389-1394.
[0093] SEQ ID NO 24 is oligo AK1.
[0094] SEQ ID NO 25 is oligo AK2.
[0095] SEQ ID NO 26 is the fragment of DNA encoding the tyl AT5
which was used for cloning, with introduced restriction enzyme
sites at bp 1-6 and bp 967-972.
DETAILED DESCRIPTION OF THE INVENTION
[0096] Culture Description
[0097] The novel strains derived from Saccharopolyspora spinosa
NRRL 18537 or Saccharopolyspora spinosa NRRL 18538 and producing
the compounds of the invention are identified in the table below.
The cultures have been deposited in accordance with the terms of
the Budapest treaty at the Midwest Area Regional Center,
Agricultural Research Service, United States Department of
Agriculture, 815 North University Street, Peoria, Ill. 61604. The
strains were deposited on Jan. 15, 2001, and assigned the deposit
numbers as detailed in Table 4 below.
4TABLE 4 Deposit Number Strain Parent Strain NRRL 30539
Saccharopolyspora spinosa 7D23 NRRL 18538 NRRL 30540
Saccharopolyspora spinosa 13E NRRL 18537 NRRL 30541
Saccharopolyspora spinosa 21K2 NRRL 18538 NRRL 30542
Saccharopolyspora spinosa 36P4 NRRL 18538
[0098] Culture Characteristics
[0099] The novel strains derived from Saccharopolyspora spinosa
NRRL 18537 or Saccharopolyspora spinosa NRRL 18538 and producing
the compounds of the invention had the following culture
characteristics:
[0100] All cultures grew well on ISP2 and Bennett's agar and aerial
hyphae were produced on all media used. The aerial spore mass was
predominately white(developing a pale pink hue with age). Substrate
mycelium was cream to light tan in color, no distinctive pigment
was apparent. A soluble brown pigment was released into the medium.
No significant differences were observed on any of the media
used.
[0101] Manipulation of Spinosyn Pathway and Accessory Genes
[0102] In order to facilitate the manipulation of the spinosyn
biosynthetic pathway, cosmids pRHB9A6 and pRHB3E11 were obtained
and are described in U.S. Pat. No. 6,274,350 B1 and Waldron et al.
(2001).
[0103] It is not directly apparent from the sequence of the
spinosyn biosynthetic genes how production of spinosyns is
regulated. In order to avoid potential complications associated
with regulation of the gene cluster, a number of heterologous
promoters were used to drive all or part of the polyketide synthase
portion (genes spnA, spnB, spnC, spnD and spnE). The following
promoters were found to be at least as efficient in the production
of spinosyn PKS as the natural promoter (judged by production of
the final products spinosyn A, spinosyn D, spinosyn A
C17-pseudoaglycone, and spinosyn D C17-pseudoaglycone): The actI
promoter from the actinorhodin biosynthetic cluster of S.
coelicolor, used along with its cognate activator, actII-ORF4, (as
described in WO 98/01546, WO 98/01571, Rowe et al. 1998) and; The
promoter for the resistance to pristinamycin. The latter has
previously been reported to drive overexpression of polyketide
genes from S. erythraea (Blanc et al. 1995; Sala-Bey et al. 1995).
It is a promoter that can be induced by physiological stresses in
Streptomyces spp. The use of heterologous promoters in S. spinosa
is not limited to those described above, and could include others
which might be expected to function in S. spinosa.
[0104] Hybrid Spinosyn PKS using Heterologous Loading Module
[0105] In one of its aspects the invention provides hybrid PKSs
that are functional in Saccharopolyspora spinosa to generate
polyketides that are processed to biologically-active spinosyns.
The resulting polyketides were extended to the same length as the
natural spinosyns, and processed by cross-bridging and
glycosylation to generate novel insecticidal spinosyns. Preferably
the hybrid PKS comprises the extension modules from the spn PKS
with a heterologous loading module that leads to a spinosyn
polyketide having a different starter unit. Hybrid spinosyn PKS
genes that contain the spn extender modules behind a heterologous
loading module can provide novel spinosyns with different side
chains at C21. The nature of this side chain is determined by the
starter unit which the loading module selects to initiate
polyketide synthesis. Changes in the side chain may alter the
physical properties or biological activity of the resulting
spinosyn. It is particularly useful to provide a hybrid PKS gene in
which the loading module accepts many different carboxylic acids,
including unnatural acids. Such a gene can be used to generate many
different spinosyns by incorporation of different starter units.
For example, the loading module of the spn PKS can be replaced by
the loading module of the ave PKS, which is known to accept a wide
variety of starter units (Dutton et al., 1991). The loading module
of the ery PKS is also known to accept alternate starter units
(Pacey et al., 1998). Thus, an organism expressing such hybrid
spinosyn PKS genes can produce novel spinosyns in which the nature
of the side chain at C21 is determined by the carboxylic acid that
is fed to the organism. The side chains can be of different
lengths, with branches or cycles, and/or contain heteroatoms.
[0106] More preferably, the hybrid PKS includes a loading module
that accepts many different carboxylic acids so the hybrid gene
assembly can be used to produce many different spinosyns.
Particularly useful examples contain the spn extension modules with
the loading module from the erythromycin (ery) PKS, or the loading
module from the avermectin (ave) PKS.
[0107] a. Hybrid Spinosyn PKS Using ery Loading Module
[0108] The loading module of the erythromycin biosynthetic cluster
(eryAT0ACP0) governs the introduction of propionyl-CoA into the
starter of the erythromycin molecule. It has been shown previously
that alternative starters can be incorporated into the erythromycin
molecule by feeding free acids to the production medium (Pacey et
al. 1998).
[0109] As shown in the following Examples, generation of a hybrid
spnA gene in which the erythromycin loading module replaces the
spinosyn loading module leads to a spinosyn PKS which can accept
free acids into the starter unit. In the following illustrative
Example, the erythromycin loading module was spliced to the
beginning of the spinosyn KS1 just within the KS domain in the
conserved region. New domain or module connections are preferably
made at conserved DNA sequences within domains, or close to the
edges thereof; however, an active polyketide synthase can
alternatively be generated by engineering splice sites in the
interdomain regions (WO 98/01546).
[0110] The ery load fragment was cloned in-frame with, and upstream
of, a region of spnA to allow homologous recombination with the
native spn PKS. Upstream of the ery load was either the actI
promoter (P.sub.actI) or the promoter for resistance to
pristinamycin (P.sub.ptr), giving rise to the plasmids pLSB61 and
pLSB62 respectively. These plasmids are based on pKC1132 and are
therefore apramycin-resistant. They also carry oriT for conjugal
transfer of DNA into actinomycetes (Bierman et al. 1992, Matsushima
et al. 1994). These constructs were transformed into S. spinosa
NRRL 18537 by conjugation. Exconjugants were confirmed to contain
the hybrid ery/spn PKS under the appropriate promoter by PCR
amplification.
[0111] S. spinosa NRRL 18537:pLSB62 was designated S. spinosa 13E,
and was used for analysis of spinosyn production.
[0112] As demonstrated in the following Examples, when cultured in
production media, S. spinosa 13E produced mainly spinosyn A and
spinosyn E, in approximately equal amounts. The total yield of
spinosyns was estimated to be approximately 10-25% of the wild-type
spinosyn A levels, which represented an increase in yield of
spinosyn E of approximately 10-fold. This altered ratio of products
may be a reflection of looser specificity of the ery loading module
relative to the spn loading module, or a reflection of the
different substrate supply in S. spinosa compared with S.
erythraea, or a combination of both. Incorporation of acetate by
the ery load has been observed in S. erythraea when the
erythromycin pathway is up-regulated (Rowe et al. 1998). The
increase in yield of spinosyn E in strain 13E over wild-type levels
means that this would be a preferred strain for the production of
spinosyn E.
[0113] A number of carboxylic acids were fed to S. spinosa 13E,
leading to the production of novel spinosyn analogues with altered
starter units. Among the novel spinosyns identified were
21-desethyl-21-cyclopropyl spinosyns A and D (by incorporation of
cyclopropane carboxylic acid), 21-desethyl-21-cyclobutyl spinosyns
A and D (by incorporation of cyclobutane carboxylic acid) and
21-desethyl-21-methylthiomethyl spinosyns A and D (from
methylthioacetic acid). The novel analogues showed reasonable
chromatographic retention times, characteristic UV chromophores and
MS fragmentation patterns, and the predicted structures were
supported by accurate mass measurements. Structural assignments of
the isolated 21-cyclopropyl and 21-cyclobutyl compounds were
confirmed by full NMR characterization. Compounds isolated were
active in insect control assays.
[0114] The use of strain S. spinosa 13E is not limited to the
production of these compounds. It is expected that a number of
other spinosyn analogues can be identified by feeding other acids,
such as those used to produce novel erythromycins (Pacey et al.
1998).
EXAMPLE 1
Construction of pCJR81
[0115] See FIG. 1. Plasmid pCJR81 is a vector for expression of
polyketide genes under the promoter for resistance to
pristinamycin. It was constructed as follows:
[0116] Two overlapping oligos were designed to perform a PCR
reaction in which they act both as primers and template. They were
designed to introduce an NdeI restriction site incorporating the
ATG start codon, such that genes can be cloned with optimal spacing
from the ribosome binding site. A SpeI restriction site was
incorporated to facilitate further cloning. The oligos are PRIS1
(SEQ ID NO:1) and PRIS2(SEQ ID NO:2).
[0117] Amplification to obtain the promoter fragment was performed
with Pwo thermostable DNA polymerase using the manufacturer's
conditions. The 112 bp fragment was phosphorylated with T4
polynucleotide kinase, and cloned into commercially-available pUC18
digested with SmaI and dephosphorylated. Plasmids containing
inserts were sequenced. One plasmid containing the correct sequence
was designated pRIS4.
[0118] The 94 bp insert from pRIS4 was excised as a SpeI/NdeI
fragment (SEQ ID NO:3) and cloned into pCJR24 (WO 98/01546, WO
98/01571, Rowe et al. 1998) which had been previously digested with
SpeI and NdeI. One correct plasmid was designated pCJR81.
EXAMPLE 2
Construction of Plasmids for Expression from S. spinosa
[0119] See FIG. 2. Plasmids pLSB2 and pLSB3 were constructed for
expression of polyketide genes or accessory genes in S. spinosa.
Plasmid pLSB2 contains the actI promoter (P.sub.actI) and its
cognate activator, actII-ORF4. Plasmid pLSB3 contains the promoter
for resistance to pristinamycin (P.sub.ptr). These plasmids were
constructed as follows:
[0120] Plasmid pKC1132 (Bierman et al. 1992) contains an origin of
transfer (oriT), and an apramycin resistance marker for selection
in both E. coli and actinomycetes. It can therefore be used for DNA
manipulations in E. coli, and permit the final plasmids to be
introduced into S. spinosa by conjugation. The polylinker of
pKC1132 was replaced by a linker of two oligos CR311 (SEQ ID NO:4)
and CR312 (SEQ ID NO:5) in order to provide appropriate
EcoRV/SpeI/NdeI/XbaI restriction sites.
[0121] Plasmid pKC1132 was digested with PvuII and the ends
dephosphorylated with shrimp alkaline phosphatase. The oligos CR311
and CR312 were phosphorylated with T4 polynucleotide kinase,
annealed and cloned into pKC1132_PvuII to generate pLSB1. A
SpeI/Ndel fragment containing the actinorhodin pathway specific
activator, actII-ORF4 and the actI promoter was isolated from
pCJR24 (WO 98/01546, WO 98/01571, Rowe et al. 1998) and a SpeI/NdeI
fragment containing the promoter for resistance to pristinamycin
was isolated from pCJR81 (described above, Example 1). Each of
these fragments was cloned independently into pLSB1 digested with
SpeI and NdeI to generate pLSB2 (containing actII-ORF4 and
P.sub.actI) and pLSB3 (containing P.sub.ptr).
EXAMPLE 3
Construction of a Vector to Incorporate the Loading Module of the
Erythromycin Polyketide Synthase into the Spinosyn Polyketide
Synthase
[0122] See FIG. 3. The vector to incorporate the loading module of
the erythromycin polyketide synthase into the spinosyn polyketide
synthase contains the erythromycin loading module (AT0ACP0),
followed by a region of the first module of the spinosyn PKS to
provide homology for integration. The vector is designated pLSB62
and was constructed as follows.
[0123] The erythromycin loading module was amplified by PCR using
pCJR26 (Rowe et al. 1998) as the template, and oligos SP28 (SEQ ID
NO:6) and SP29 (SEQ ID NO:7). SP28 incorporates an NdeI site at the
start codon of the ery sequence, and SP29 incorporates an NheI site
at the beginning of the KS1 domain.
[0124] The PCR fragment was phosphorylated, gel-purified and cloned
into pUC18 which had been previously digested with SmaI and
dephosphorylated. Clones were screened for the presence of inserts
and sequenced. One clone containing the correct sequence was
designated pLSB44. It contained the insert in the orientation with
the NheI site close to the EcoRI site of the polylinker. The
sequence of the erythromycin loading module fragment used, from the
NdeI site to the NheI site is shown in SEQ ID NO 8.
[0125] Plasmid pLSB8 (described in Example 11) contains a fragment
of spnA starting with the NheI site at spnKS1. The fragment
containing the erythromycin loading module was excised from pLSB44
as an NdeI/NheI fragment and cloned into pLSB8 previously digested
with NdeI and NheI, to give pLSB56. The fragment contained in
pLSB56 contains the erythromycin loading module spliced in-frame to
the spinosyn KS1, with a region of homology to spnA which is
sufficient for integration to occur.
[0126] This region was removed as an NdeI/XbaI fragment and cloned
into pLSB3 to give pLSB62. This places the new ery/spn hybrid
fragment under P.sub.ptr, in a vector which can be transferred into
S. spinosa by conjugation and selected using the apramycin
resistance marker.
EXAMPLE 4
Generation of a S. spinosa Strain Harbouring a Hybrid Polyketide
Synthase Comprising the Erythromycin Loading module fused to the
KS1 of the Spinosvn PKS.
[0127] See FIG. 4. Saccharopolyspora spinosa NRRL 18537 was
transformed by conjugation (Matsushima et al. 1994) from E. coli
S17-1 (Simon et al., 1983) with pLSB62. Transformants were selected
for apramycin resistance and screened by PCR. A single transformant
was designated strain S. spinosa 13E.
EXAMPLE 5
Chemical Analysis of S. spinosa Fermentations
[0128] The following HPLC method is useful for analyzing
fermentations for the production of natural spinosyns and novel
non-natural engineered spinosyns.
[0129] In a 2 mL Eppendorf tube, an aliquot of fermentation broth
(1 mL) was adjusted to pH.about.10 by the addition of 20% ammonia
solution (ca. 20 .mu.l). Ethyl acetate (1 mL) was added to the
sample and mixed vigorously for 60 seconds using a vortex. The
mixture was separated by centrifugation in a microfuge and the
upper phase removed to a clean 2 mL Eppendorf tube. The ethyl
acetate was removed by evaporation using a Speed-vac. Residues were
dissolved into methanol (250 .mu.l) and clarified using a
microfuge. Analysis was by the following HPLC system:
[0130] Injection volume: 50 .mu.l
[0131] Column stationary phase: 150.times.4.6 mm column,
base-deactivated silica gel 3.mu.m (Hypersil C.sub.18-BDS).
[0132] Mobile phase A: 10% acetonitrile:90% water, containing 10 mM
ammonium acetate and 0.15% formic acid.
[0133] Mobile phase B: 90% acetonitrile:10% water, containing 10 mM
ammonium acetate and 0.15% formic acid.
[0134] Mobile phase gradient: T=0 min, 10% B; T=1, 10% B; T=25, 95%
B; T=29, 95% B; T=29.5, 10% B.
[0135] Flow rate: 1 mL/min.
[0136] Detection: UV at 254 nm; MS over m/z range 100-1000.
EXAMPLE 6
Production of Metabolites by S. spinosa 13E Fermentation
[0137] S. spinosa 13E was cultured from a frozen vegetative stock
(1:1 CSM culture:cryopreservative, where the cryopreservative is
10% lactose, 20% glycerol w/v in water). A primary pre-culture was
grown in CSM medium (tryptic soy broth 30 g/l, yeast extract 3 g/l,
magnesium sulfate 2 g/l, glucose 5 g/l, maltose 4 g/l; Hosted and
Baltz 1996; U.S. Pat. No. 5,362,634), in a 50 mL culture in a 250
mL Erlenmeyer flask with a steel spring, shaken at 250 rpm with a
two-inch throw at 30.degree. C., 75% relative humidity for 3 days.
This was used to inoculate a secondary pre-culture in vegetative
medium (glucose 10 g/l, N-Z-amine A 30 g/l, yeast extract 3 g/l,
magnesium sulfate 2 g/l; Strobel and Nakatsukasa 1993; U.S. Pat.
No. 5,362,634) at 5% v/v, which was cultured under the same
conditions for a further 2 days. The secondary vegetative
pre-culture was used to inoculate production medium (glucose 67
g/l, Proflo cottonseed flour 25 g/l, peptonized milk nutrient 22
g/l, corn steep liquor 12 g/l, methyl oleate 40 g/l, calcium
carbonate 5 g/l, pH to 7.0 with sodium hydroxide; Strobel and
Nakatsukasa 1993) at 5% v/v. Small scale production cultures were
fermented under the same conditions as the pre-cultures, but for
7-10 days. For initial S. spinosa 13E production, small-scale
cultures were grown in 30 mL of production medium in 250 mL
Erlenmeyer flasks with springs for 7 days.
[0138] For the identification of metabolites produced, a 1 mL
aliquot of fermentation broth was analyzed by LC-MS as described in
Example 5. By comparison to authentic standards, and to a
fermentation extract from non-transformed strain S. spinosa NRRL
18537, the major compounds produced by S. spinosa 13E were
identified as spinosyns A and E (which are produced in
approximately equal amounts) and spinosyn D (which was observed as
a minor product). The titer of strain S. spinosa 13E was
.about.10-15 mg/l of total spinosyns. The ratio of products for S.
spinosa 13E was different to NRRL 18537, with the relative
production of spinosyn E being significantly increased.
EXAMPLE 7
Precursor-directed Production of Novel Spinosyns from S. spinosa
13E (Production of Compounds 1-6).
[0139] The ery/spn hybrid PKS was used to generate novel spinosyn
metabolites by feeding carboxylic acids to production cultures. The
ery loading module incorporated the carboxylic acid within the
starter of the molecule.
[0140] Parallel production flasks (30 mL in 250 mL Erlenmeyer flask
with spring) were inoculated as described in Example 6 above. After
24 h each of these was fed with a carboxylic acid (stock solutions
made in water and pH adjusted to 6.5 with sodium hydroxide) at a
final concentration of 2-6 mM. After 7 days a 1 mL aliquot of
fermentation broth was analyzed by LC-MS as described in Example 5.
The incorporation of cyclobutyl carboxylic acid, cyclopropyl
carboxylic acid and methylthioacetic acid to generate novel C21
modified spinosyns was indicated by the appearance of novel peaks
in the UV and MS chromatograms (Table 5). The MS spectra of the
novel compounds gave ions for the [M+H].sup.+ species and for the
forosamine fragment (142.3).
5TABLE 5 Compound Retention No. time Key Mass Spectral Carboxylic
acid fed (see Table 3) (min) data (m/z) cyclopropyl carboxylic 1
23.5 744.4 [M + H].sup.+; 142.4 acid cyclopropyl carboxylic 2 25.0
758.5 [M + H].sup.+; 142.3 acid cyclobutyl carboxylic 3 25.7 758.5
[M + H].sup.+; 142.3 acid cyclobutyl carboxylic 4 27.3 772.5 [M +
H].sup.+; 142.2 acid methylthio acetic acid 5 22.9 764.4 [M +
H].sup.+; 142.3 methylthio acetic acid 6 24.3 778.5 [M + H].sup.+;
142.3
EXAMPLE 8
Production and Isolation of 21-desethyl-21-cyclobutyl Spinosyns A
and D
(Compounds 3 and 4)
[0141] Frozen vegetative stocks of S. spinosa 13E were inoculated
into primary vegetative pre-cultures in CSM (50 mL incubated in a
250 mL Erlemneyer flask with spring). Secondary pre-cultures in
vegetative medium (250 mL incubated in a 2 L Erlenmeyer flask with
spring) were prepared and incubated as described in Example 6, but
at 300 rpm with a one-inch throw.
[0142] Twelve to 14 L of production medium was prepared, as in
Example 6, with the addition of 0.01% v/v Pluronic L-0101 (BASF)
antifoam. Production medium was inoculated with the secondary
vegetative pre-culture at 5% v/v, and allowed to ferment in a 20 L
stirred bioreactor for 7-10 days at 30.degree. C. Airflow was set
at 0.75 vvm, over pressure was set at 0.5 barg or below, and
impeller tip speed was controlled between 0.39 and 1.57 ms.sup.-1
in order to maintain dissolved oxygen tension at or above 30% of
air saturation. Additional Pluronic L0101 (BASF) was added to
control foaming, if needed. Cyclobutyl carboxylic acid was fed to
the bioreactor at 25 hours, to a final concentration of 5 mM. The
fermentation broth was harvested after 7 days and clarified by
centrifugation to provide supernatant and cells. The cells (1 L)
were extracted by mixing thoroughly with an equal volume of
methanol then allowed to stand for 30 min. The cell-methanol slurry
was centrifuged, and the supernatant decanted off. The procedure
was repeated. The fermentation supernatant (12 L) was adjusted to
pH.about.10 by addition of 5 N NaOH and stirred gently with 0.75
volumes of ethyl acetate for 8 hours. The upper phase was removed
by aspiration and the extraction repeated. The ethyl acetate and
methanol fractions were combined and the solvents removed in vacuo
to yield a yellow-brown oil/aqueous mixture (1 L). This was mixed
with ethyl acetate (2 L) and extracted with a solution of 50 mM
tartaric acid (3.times.1.5 L). The tartaric acid extracts were
combined, adjusted to pH.about.10 with 5 N NaOH, and extracted with
ethyl acetate (3.times.1.5 L). The ethyl acetate extracts were
combined and the solvent removed in vacuo to leave a brown oily
residue (7.5 g). The residue was dissolved into ethyl acetate (500
mL) and extracted three times with 50 mM tartaric acid (350 mL).
The tartaric acid fractions were combined, adjusted to pH.about.10
and re-extracted with ethyl acetate (3.times.500 mL). The ethyl
acetate fractions were combined and the solvent removed in vacuo to
yield a brown oily residue (0.5 g).
[0143] The oily residue was dissolved into methanol (1.5 mL) and
chromatographed, in two equal portions, over base-deactivated
reversed-phase silica gel (Hypersil C.sub.18-BDS, 5 .mu.m;
21.times.250 mm) eluting with a mobile phase gradient as described
below, at a flow rate of 21 mL/min.
[0144] Mobile phase gradient: T=0 min, 15% B; T=5, 35% B; T=35, 90%
B; T=45, 95% B.
[0145] Mobile-phase A: 10% acetonitrile/90% water, containing 10 mM
ammonium acetate and 0.15% formic acid.
[0146] Mobile-phase B: 90% acetonitrile/10% water, containing 10 mM
ammonium acetate and 0.15% formic acid.
[0147] Fractions were collected every 30 seconds. Fractions from
the initial fractionation that contained 21-desethyl-21-cyclobutyl
spinosyn A were combined, and the solvent removed in vacuo. The
residues were chromatographed over reversed-phase silica gel
(Prodigy C,.sub.18, 5 .mu.m; 10.times.250 mm) eluting with a
gradient as described below, at a flow rate of 5 mL/min.
[0148] T=0, 55% B; T=5, 70% B; T=35, 95% B; T=45, 95% B.
[0149] Fractions were collected every 30 seconds. Fractions
containing the 21-desethyl-21-cyclobutyl spinosyn A were combined,
the acetonitrile removed in vacuo, and the sample concentrated
using C.sub.18-BondElute cartridges (200 mg). The sample was
applied under gravity, washed with water (10 mL) and eluted with
methanol (2.times.10 mL), then the solvent removed in vacuo.
Fractions from the initial crude fractionation that contained
21-desethyl-21-cyclobutyl spinosyn D were combined and the solvent
removed in vacuo. The residues were chromatographed over
reversed-phase silica gel (Prodigy C.sub.18, 5 .mu.m; 10.times.250
mm) eluting with a gradient as described below, at a flow rate of 5
mL/min.
[0150] T=0 min, 25% B; T=5, 55% B; T=35, 95% B; T=45, 95% B.
[0151] Fractions were collected every 30 seconds. Fractions
containing the 21-desethyl-21-cyclobutyl spinosyn D were combined,
the acetonitrile removed in vacuo, and the sample centrated using
C.sub.18-BondElute cartridges (200 mg capacity). The sample was
applied under gravity, washed with water (10 mL) and eluted with
methanol (2.times.10 mL), and the vent removed in vacuo.
[0152] The chemical structures of the new spinosyns were determined
by spectroscopic methods, including nuclear magnetic resonance
spectroscopy (NMR), mass spectrometry (MS), ultraviolet
spectrometry (UV), coupled high performance liquid
chromatography-mass spectrometry (HPLC-MS), and by comparison to
the spectral data for the known compounds spinosyns A, D, E and
F.
[0153] 21-desethyl-21-cyclobutyl spinosyn A (Compound 3) has the
following characteristics:
[0154] Isolated yield: 3.1 mg
[0155] Molecular weight: 757
[0156] Molecular formula: C.sub.43H.sub.67NO.sub.10
[0157] UV (by diode array detection during HPLC-MS analysis): 245
nm
[0158] Electrospray MS: m/z for [M+H].sup.+=758.5; forosamine sugar
fragment ion at m/z=142.2.
[0159] Accurate FT-ICR-MS: m/z for [M+H].sup.=758.4830 (requires:
758.4838).
[0160] Table 6 shows the .sup.1H and .sup.13C NMR chemical shift
data for 21-desethyl-21-cyclobutyl spinosyn A in CDCl.sub.3.
6 TABLE 6 Position .sup.1H .sup.13C 1 -- 172.8 2a 2.43 33.8 2b 3.12
33.8 3 3.01 47.5 4 3.54 41.7 5 5.80 128.8 6 5.88 129.3 7 2.17 41.1
8a 1.37 36.2 8b 1.92 -- 9 4.31 76.0 10a 1.33 37.3 10b 2.26 -- 11
0.91 46.0 12 2.88 49.4 13 6.76 147.5 14 -- 144.2 15 -- 202.9 16
3.26 47.8 16-Me 1.17 16.1 17 3.61 80.6 18a 1.49 34.4 18b 1.49 --
19a -- 21.7 19b -- -- 20a 1.34 28.2 20b 1.44 -- 21 4.80 22 2.34 23a
1.65 23b 1.65 24a 1.76 17.8 24b 1.76 -- 25a 1.86 24.6 25b 1.86 --
1' 4.85 95.4 2' 3.49 77.7 3' 3.46 81.0 4' 3.12 82.2 5' 3.54 67.9 6'
1.28 17.8 2'-OMe 3.49 59.0 3'-OMe 3.50 57.7 4'-OMe 3.56 60.9 1"
4.42 103.4 2"a 1.47 30.8 2"b 1.98 -- 3"a 1.47 18.5 3"b 1.98 -- 4"
2.26 64.8 5" 3.84 73.5 6" 1.26 19.0 4"-NMe.sub.2 2.26 40.6 Chemical
shifts referenced to the proton of CHCl.sub.3 at 7.26 ppm
[0161] 21-desethyl-21-cyclobutyl spinosyn D (Compound 4) had the
following characteristics:
[0162] Isolated yield: .about.1 mg
[0163] Molecular weight: 771
[0164] Molecular formula: C.sub.44H.sub.69NO.sub.10
[0165] UV (by diode array detection during HPLC-MS analysis): 245
nm
[0166] Electrospray MS: m/z for [M+H].sup.+=772.5; forosamine sugar
fragment ion at m/z=142.2.
[0167] The small quantity of material precluded detailed NMR study
of this molecule, but the data accumulated was consistent with the
expected structure. This analysis was aided by comparison to the
data for 21-desethyl-21-cyclobutyl spinosyn A.
EXAMPLE 9
Preparation of 5,6-dihydro-21-desethyl-21-cyclobutyl spinosyn A
(Compound 8) and 5,6-dihydro-21-desethyl-21-n-propyl Spinosyn A
(Compound 29)
[0168] A solution of 21-desethyl-21-cyclobutyl spinosyn A (3.1 mg,
0.004 mmol) in 2 mL of toluene and 0.5 mL of ethanol was purged
with a slow stream of nitrogen for 20 minutes, then 2 mg of
chlorotris(triphenylphosp- hine) rhodium was added and the solution
hydrogenated at 60.degree. C. and 1 atm. for 16 hours. After
cooling and removal of solvent, the residue was chromatographed
using a 10 cm.times.2 cm silica gel column, eluting with 5.times.25
mL fractions of dichloromethane containing 0%, 2%, 3%, 4%, and 5%
MeOH respectively. The product-containing fractions were combined
and concentrated to give 2.1 mg of 5,6-dihydro-21-desethyl-21-cy-
clobutyl spinosyn A. MS M+760.
[0169] 5,6-dihydro-21-desethyl-21-n-propyl spinosyn A (Compound 29)
was prepared from 21-desethyl-21-n-propyl spinosyn A (Compound 23)
using the same procedure.
EXAMPLE 10
Production and Isolation of 21-desethyl-21-cyclopropyl Spinosyns A
and D
(Compounds 1 and 2)
[0170] Frozen vegetative stocks of S. spinosa 13E were inoculated
into primary vegetative pre-cultures in CSM (50 mL incubated in a
250 mL Erlenmeyer flask with spring). Secondary pre-cultures in
vegetative medium (250 mL incubated in a 2 L Erlenmeyer flask with
spring) were prepared and incubated as described in Example 8.
[0171] Fourteen litres of production medium were prepared, as in
Example 6, with the addition of 0.01% v/v Pluronic L-0101 (BASF)
antifoam. Production medium was inoculated with the secondary
pre-culture at 5% v/v and allowed to ferment in a 20 L stirred
bioreactor for 7-10 days under the conditions described in Example
8. Cyclopropyl carboxylic acid was fed to the bioreactor at 45
hours to a final concentration of 5 mM. The fermentation broth was
harvested after 7 days and extracted as described in Example 8.
[0172] The oily residue was dissolved in methanol (1.5 mL) and
initially crudely chromatographed as described in Example 8.
Fractions from the initial separation that contained
21-desethyl-21-cyclopropyl spinosyn A were combined and the solvent
removed in vacuo. The residues were chromatographed over
reversed-phase silica gel (Prodigy C.sub.18, 5 .mu.M; 10.times.250
mm) eluting with a gradient as described below, at a flow rate of 5
mL/min.
[0173] T=0 min, 55% B; T=70% B; T=30, 95% B; T=35, 95% B.
[0174] Fractions were collected every 30 seconds. Fractions
containing the 21-desethyl-21-cyclopropyl spinosyn A were combined,
the acetonitrile removed in vacuo, and the sample concentrated
using a C.sub.18-BondElute cartridge (200 mg). The sample was
applied under gravity, washed with water (10 mL) and eluted with
methanol (2.times.10 mL), and then the solvent was removed in
vacuo.
[0175] 21-desethyl-21-cyclopropyl spinosyn A (Compound 1) has the
following racteristics:
[0176] Isolated yield: .about.1 mg
[0177] Molecular weight: 743
[0178] Molecular formula: C.sub.42H.sub.65NO.sub.10
[0179] UV (by diode array detection during HPLC-MS analysis): 245
nm
[0180] Electrospray MS: m/z for [M+H].sup.+=744.5; forosamine sugar
fragment ion at m/z=142.2.
[0181] Table 7 summarizes the .sup.1H and .sup.13C NMR spectral
data for 21-desethyl-21-cyclopropyl spinosyn A in CDCl.sub.3.
7 TABLE 7 Position .sup.1H .sup.13C 1 -- -- 2a 2.43 34.0 2b 3.13 --
3 3.00 47.3 4 3.49 41.4 5 5.87 129.1 6 5.79 128.6 7 2.15 -- 8a 1.34
36.0 8b 1.91 -- 9 4.30 75.9 10a 1.32 37.0 10b 2.24 -- 11 0.89 45.9
12 2.85 34.0 13 6.74 147.4 14 -- -- 15 -- -- 16 3.26 47.5 17 3.62
80.6 18a 1.51 34.2 18b 1.51 -- 19a 1.18 22.0 19b 1.74 -- 20a 1.62
30.9 20b 1.62 -- 21 4.18 79.3 22 0.89 16.5 23a* 0.44 2.3 23b* 0.14
-- 24a* 0.44 3.7 24b* 0.14 -- 25 1.17 16.0 1' 4.84 95.2 2' 3.49
77.5 3' 3.45 80.9 4' 3.10 82.1 5' 3.54 67.7 6' 1.27 17.6 2'-OMe
3.49 58.8 3'-OMe 3.48 57.5 4'-OMe 3.55 60.7 1" 4.41 103.4 2"a 1.47
30.8 2"b 1.98 -- 3"a 1.45 18.2 3"b 2.24 -- 4" 2.24 64.7 5" 3.48
73.4 6" 1.27 18.7 4"-NMe.sub.2 2.24 40.6 Chemical shifts referenced
to the proton of CHCl.sub.3 at 7.26 ppm. *These assignments are
interchangeable.
[0182] 21-desethyl-21-cyclopropyl spinosyn D (Compound 2) has the
following characteristics:
[0183] Isolated yield: .about.0.5 mg
[0184] Molecular weight: 757
[0185] Molecular formula: C.sub.43H.sub.67NO.sub.10
[0186] UV (by diode array detection during HPLC-MS analysis): 245
nm
[0187] Electrospray MS: m/z for [M+H].sup.+=758.5; forosamine sugar
fragment ion at m/z=142.2.
[0188] The small quantity of material precluded the detailed NMR
study of this molecule, but the data accumulated was consistent
with the expected structure. This analysis was aided by comparison
to the data for 21-desethyl-21-cyclopropyl spinosyn A.
b. Hybrid Spinosyn PKS Using ave Loading Domain
[0189] The loading module of the avermectin biosynthetic cluster
(aveAT0ACP0) governs the introduction of C-2 branched starter units
into the avermectin molecule, derived from iso-butyryl-CoA and
2-methylbutyryl-CoA. There is precedent for the swapping of this
loading domain into the erythromycin PKS pathway to give novel
polyketides with the starter unit specificity of the avermectin
system (WO 98/01546, WO 98/01571, Marsden et al. 1998). The
avermectin loading module has also been shown to incorporate
CoA-esters of a broad range of free acids from the production
medium, either in its native environment, or as part of the ave/ery
hybrid pathway (Pacey et al. 1998). The avermectin loading module
swap described in the literature is actually a replacement of the
erythromycin AT0ACP0 by the avermectin AT0ACP0. This leads to a
piece of erythromycin DNA sequence upstream of the avermectin AT0
between the start codon and a SpeI site. This was included in the
ave/ery experiment because the N-terminal region (upstream of the
homologous AT domain) is much larger in the erythromycin loading
module than in that of avermectin, and may be important for
stability of the protein. Because the resulting hybrid had been
productive, the same region was used for the ave/spn hybrid. In
effect, the resulting hybrid gene is an ery/ave/spn hybrid, but
since it transfers the specificity of the avermectin loading module
to the spinosyn PKS, it has been designated an ave/spn hybrid
through-out.
[0190] The avermectin loading module (AT0ACP0) was cloned from pIG1
(WO 98/01546, WO 98/01571, Marsden et al. 1998) in-frame and
upstream of the spnKS1, under the control of either P.sub.actI, or
P.sub.ptr. The same splice site, at the beginning edge of the KS1
homologous region, was used as for the ery load experiment
described above. A region of homology for integration was
incorporated from pRHB3E11. The resulting plasmids, pLSB29 (with
the hybrid PKS region under the control of P.sub.actI) and pLSB30
(with the hybrid PKS region under the control of P.sub.ptr) are
based on pKC1132 and therefore contain the apramycin resistance
marker for selection both in E. coli and S. spinosa, and the oriT
for conjugal transfer of DNA from E. coli to S. spinosa (Bierman et
al. 1992, Matsushima et al. 1994). These constructs were
transformed into S. spinosa NRRL 18538 by conjugation. Exconjugants
were confirmed to contain the hybrid ave/spn PKS gene under the
appropriate promoter by PCR analysis.
[0191] S. spinosa NRRL 18538:pLSB29 was designated S. spinosa 21K2.
It produced mainly spinosyns E, A and D by incorporation of acetate
and propionate into the loading module. Additional small peaks were
observed in LC-MS, with masses that were consistent with the novel
natural products 21-desethyl-21-iso-propyl spinosyn A and
21-desethyl-21-sec-buty- l spinosyn A and the equivalent D
analogues. These minor products resulted from incorporation of
iso-butyrate and 2-methyl butyrate respectively into the starter.
In avermectin biosynthesis itself, the ave loading module recruits
only these branched starters. However, a broader spectrum of
products was observed when the ave loading module was spliced
upstream of the KS1 in the erythromycin PKS, indicating that such a
hybrid can incorporate acetate and propionate as well. We therefore
observed the expected range of products from this engineered S.
spinosa strain.
[0192] The structure of isolated 21-desethyl-21-iso-propyl spinosyn
A was confirmed by NMR characterization. 21-desethyl-21-n-propyl
spinosyn A was isolated as a minor component from the production
culture of 21-desethyl-21-iso-propyl spinosyn A. The 21-n-propyl
analogue, presumably made by the loading module taking butyrate
from the medium, was also fully characterized. Both were active in
insect control assays.
[0193] Some of the natural versatility of the loading module of the
avermectin PKS had previously been transferred to the erythromycin
system, so a broad range of free acids was fed to S. spinosa 21K2
to generate spinosyns with altered starter units. Novel spinosyn
compounds were identified on the basis of UV chromophore, mass and
mass spectral fragmentation, along with the knowledge of which acid
was fed and therefore which compounds were expected from each
experiment. To confirm the structure predictions made, a number of
spinosyn analogues with novel C21 starter groups were isolated and
fully characterized.
[0194] Free acids which can be used in this way include, but are
not limited to, the following: Cyclic organic acids including
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl and
2-methylcyclopropyl; heteroatom containing cyclic organic acids
including 2-furoic acid, 3-furoic acid, thiophene carboxylic acid
and methyl thiophene carboxylic acid; branched chain carboxylic
acids; and some other acids which included methylthioacetic acid,
chloroacetic acid, cyanoacetic acid and methoxyacetic acid.
[0195] Such feeding experiments lead to analogues of spinosyns (a
spinosyn being a macrolide with a 22-membered tetracyclic nucleus
of the type illustrated in Tables 1 and 2 and in Formula I) in
which C21 bears a side chain other than ethyl, generally an
alpha-branched C2-C5 alkyl group, a C3-C8 cycloalkyl or
cycloalkenyl group (optionally substituted e.g. with one or more
hydroxy, C1-4 alkyl or alkoxy groups or halogen atoms), or a 3-6
membered heterocycle containing O or S, saturated or fully or
partially unsaturated, optionally substituted (as for cycloalkyl).
Preferred candidates for the C21 substituent arc the groups of
carboxylate units useable as substrates by the ery or ave loading
modules. Preferred substrates include cyclobutane carboxylic acid
and cyclopropane carboxylic acid. Other possibilities include
n-butyric acid, iso-propyl carboxylic acid, 2-(S)-methylbutyric
acid, 2-methylcyclopropane carboxylic acid, 3-furoic acid and
methylthioacetic acid.
[0196] Feeding the branched chain acids iso-propyl and 2-methyl
butyl carboxylic acid did not alter the yield of novel natural
products made due to the normal specificity of the ave load. These
products were observed in all healthy cultures of S. spinosa 21K2
in low yield.
[0197] Cyclobutyl carboxylic acid was accepted by the ave loading
module to give the A and D analogues, and a substantial proportion
of the C17-pseudoaglycone of the A analogue. The cyclobutyl
products were observed at higher levels than in the fed hybrid
ery/spn system, with 21-desethyl-21-cyclobutyl spinosyn A at
.about.5-10 mg/litre, 21-desethyl-21-cyclobutyl spinosyn D at lower
but significant levels and 21-desethyl-21-cyclobutyl spinosyn A
17-pseudoaglycone at .about.10-15 mg/litre. The cyclopropyl
carboxylic acid feed was also successful, yielding
21-desethyl-21-cyclopropyl spinosyns A and D. The two cyclobutyl
analogues and the cyclopropyl A analogue were shown to be identical
to the purified compounds isolated from the ery load
experiment.
[0198] Methylthioacetic acid was incorporated to give the
21-desethyl-21-methylthiomethyl spinosyn A, at yields comparable to
those of the cyclobutyl experiment above. This was a significant
improvement in yield over production of the same compound from the
ery load experiment. 2-furoic acid and methylcyclopropyl carboxylic
acid were also incorporated to give the expected novel
products.
EXAMPLE 11
Construction of a Vector to Incorporate the Loading Module of the
Avermectin Polyketide Synthase into the Spinosyn Polyketide
Synthase
[0199] See FIG. 5. The vector to incorporate the loading module of
the avermectin polyketide synthase into the spinosyn polyketide
synthase contains the avermectin loading module (AT0ACP0) followed
by a region of the first module of the spinosyn PKS to provide
homology for integration. The vector is designated pLSB29 and was
constructed as follows:
[0200] The avermectin loading module has been previously spliced
upstream of the erythromycin module 1 (WO 98/01546, WO 98/01571,
Marsden et al. 1998). In this ave/ery hybrid the loading module had
the DNA coding for the ery amino acid sequence at the start,
followed by the AT0ACP0 of the ave PKS. This hybrid fragment
conferred the specificity of the avermectin loading domain,
although it included a small amount of ery sequence. The same
fragment was used in this experiment, and leads to an ery/ave/spn
hybrid protein. We describe it simply as an ave/spn hybrid since it
is the specificity of the avermectin loading domain that is
conferred on the spinosyn pathway. The fragment begins with an NdeI
site incorporating the start codon, and ends with a NheI site
engineered at the beginning of the KS1. This introduces a
conservative amino acid change (Ile-Leu) in the spinosyn KS1
sequence.
[0201] To introduce the NheI site, the region of spna from the
beginning of the KS1 was amplified by PCR using pRHB3E11 (U.S. Pat.
No. 6,274,350 B1, Waldron et al. 2001) as the template, and oligos
SP14 (SEQ ID NO:9) and SP15 (SEQ ID NO:10). SP14 introduces an NheI
site at bases 24107-24112 (numbers refer to SEQ ID NO:1 of U.S.
Pat. No. 6,274,350). SP15 binds approximately 1500 bp downstream,
at a BstEII site (25646-25652). A NotI site was also incorporated
into SP15 for the subsequent cloning step. The PCR was carried out
using Pwo thermostable polymerase under standard conditions.
[0202] The PCR product was phosphorylated, gel-purified and cloned
into pUC19 which had been previously digested with SmaI and
dephosphorylated. A number of insert-containing clones were
sequenced. One clone containing the insert in the orientation which
places the NheI site next to the EcoRI site in the vector was
designated pLSB5.
[0203] To provide a large enough region of homology for
integration, a fragment of approximately 2.6 kbp (from BstEII to
NotI) was cloned out of pRHB3E11 into pLSB5, to yield pLSB8.
[0204] The avermectin loading module was then cloned from pIG1 (WO
98/01546, WO 98/01571, Marsden et al. 1998) as an NdeI/NheI
fragment and ligated into pLSB8 previously digested with NdeI and
NheI. The DNA sequence of the avermectin loading module fragment
used, from the NdeI site to the NheI site is shown in SEQ ID NO 11.
The resulting plasmid was designated pLSB14.
[0205] The fragment contained in pLSB14 contains the avermectin
loading module spliced in-frame to the spinosyn KS1, with a region
of homology to spnA which is sufficient for integration to
occur.
[0206] This fragment was then removed as an NdeI/XbaI fragment and
cloned into pLSB2 to give pLSB29. This places the new ave/spn
hybrid fragment under PactI, in a vector which can be transferred
into S. spinosa by conjugation and then selected using the
apramycin resistance marker.
EXAMPLE 12
Generation of a S. spinosa Strain Harbouring a Hybrid Polyketide
Synthase Comprising the Avermectin Loading Module Fused to the KS1
of the Spinosyn PKS
[0207] See FIG. 6. Saccharopolyspora spinosa NRRL 18538 was
transformed by conjugation (Matsushima et al. 1994) from E. coli
S17-1 (Simon et al., 1983) with pLSB29. Transformants were selected
by resistance to apramycin and screened by Southern blot analysis.
A single transformant displaying the correct hybridization pattern
to show that the plasmid had integrated into the chromosome by
homologous recombination was designated strain S. spinosa 21K2.
EXAMPLE 13
Production of Metabolites by S. spinosa 21K2 Fermentation
(Production of Compounds 9-12)
[0208] S. spinosa 21 K2 was cultured from a frozen vegetative stock
used to inoculate CSM medium (Hosted and Baltz 1996; U.S. Pat. No.
5,362,634). This pre-culture was grown in flasks shaken at 300 rpm
with a one-inch throw at a temperature of 30.degree. C. for 3 days.
This was used to inoculate vegetative medium (Strobel and
Nakatsukasa 1993; U.S. Pat. No. 5,362,634) at 5% v/v and was
cultured under the same conditions for a further 2 days. The
vegetative culture was used to inoculate production medium (Strobel
and Nakatsukasa 1993) at 5% v/v. Small-scale production cultures
were fermented under the same conditions as the pre-cultures, but
for 7-10 days at 250 rpm with a two-inch throw and at 75% relative
humidity. Initial small-scale production cultures were grown in 6
mL of production medium in 25 mL Erlenmeyer flasks with springs for
7 days.
[0209] To identify the metabolites produced, a 1 mL aliquot of
fermentation broth was analyzed by LC-MS as described in Example 5.
By comparison to authentic standards, and to a fermentation extract
from strain S. spinosa NRRL 18538, the major compounds produced by
S. spinosa 21 K2 were spinosyns A, D and E. Spinosyn A was the
major component produced, and the total yield of spinosyns was
.about.50 mg/l.
[0210] In addition to the known spinosyns A, D and E, four new
compounds were clearly present.The chromatographic retention time
and mass spectral data for these new compounds (Table 8) were
consistent with their synthesis through the incorporation of
branched chain starter units (iso-propyl carboxylic acid and
2-methylbutyric acid). The MS spectra of the new compounds gave
ions for the [M+H]+ species and for the forosamine fragment
(142.3). The compounds derived from an iso-propyl carboxylic acid
feed were present 2-3.times. higher levels than those derived from
2-methylbutyric acid. The new compounds comprised no more than 5%
of the total spinosyns present.
8TABLE 8 Compound Retention Carboxylic acid No. time Key mass
spectral starter unit (see Table 3) (min) data (m/z) iso-propyl
carboxylic 9 25.1 746.5 [M + H].sup.+; 142.3 acid iso-propyl
carboxylic 10 26.3 760.5 [M + H].sup.+; 142.3 acid 2-methylbutyric
acid 11 26.7 760.4 [M + H].sup.+; 142.3 2-methylbutyric acid 12
27.5 774.5 [M + H].sup.+; 142.3
EXAMPLE 14
Precursor-directed Production of Novel Spinosyns from S. spinosa
21K2 (Production of Compounds 1-6 and 13-20)
[0211] The ave/spn hybrid PKS was used to generate novel spinosyn
metabolites by feeding carboxylic acids to production cultures. The
avermectin loading module incorporated the carboxylic acid within
the starter of the molecule.
[0212] Parallel 6 mL production flasks were inoculated as described
in Example 13 above. After 24 h each of these was fed with a
carboxylic acid (stock solutions made in water and pH adjusted to
6.5 with sodium hydroxide) at a final concentration of 3 mM. After
7 days a 1 mL aliquot of fermentation broth was analyzed by LC-MS
as described in Examples 6 and 12. The incorporation of cyclobutyl
carboxylic acid, cyclopropyl carboxylic acid, 2-methylcyclopropyl
carboxylic acid, methylthio acetic acid and 3-furoic acid provided
novel C21-modified spinosyns, as indicated by the appearance of new
peaks in the UV and MS chromatograms (Table 9). The mass spectra of
the novel compounds gave ions for the [M+H].sup.+ species and for
the forosamine fragment (142.3). In addition the feeding of
cyclobutyl- and cyclopropyl carboxylic acids also caused
significant accumulation of the corresponding
17-pseudoagylcones.
9TABLE 9 Compound Retention No. time Key mass Carboxylic acid fed
(see Table 3) (min) spectral data (m/z) cyclobutyl CA 2 25.7 758.4
[M + H].sup.+; 142.4 cyclobutyl CA 3 27.2 772.5 [M + H].sup.+;
142.4 cyclopropyl CA 1 23.5 744.5 [M + H].sup.+; 142.4 cyclopropyl
CA 2 25.1 758.5 [M + H].sup.+; 142.4 2-methyl cyclopropyl 13 25.7
758.5 [M + H].sup.+; 142.4 CA 2-methyl cyclopropyl 14 26.9 772.5 [M
+ H].sup.+; 142.4 CA methylthio acetic acid 5 22.9 764.5 [M +
H].sup.+; 142.4 methylthio acetic acid 6 24.4 778.4 [M + H].sup.+;
142.4 3-furoic acid 15 22.9 770.5 [M + H].sup.+; 142.4 3-furoic
acid 16 24.3 784.5 [M + H].sup.+; 142.4 cyclobutyl CA 19 27.1 639.4
[M + Na].sup.+ cyclobutyl CA 20 28.6 653.4 [M + Na].sup.+
[0213] The 21-cyclobutyl and cyclopropyl compounds were confirmed
as the correct structures in comparison to the compounds isolated
from feeding the ery load strain, S. spinosa 13E.
EXAMPLE 15
Isolation of Novel Metabolites from a Large-scale Fermentation of
S. spinosa 21K2
[0214] Frozen vegetative stocks of S. spinosa 21K2 were inoculated
into primary vegetative pre-cultures of S. spinosa 21K2 in CSM (50
mL incubated in a 250 mL Erlenmeyer flask with spring). Secondary
pre-cultures in vegetative medium (250 mL incubated in a 2 L
Erlenmeyer flask with spring) were prepared and incubated as
described in Example 6.
[0215] Fourteen litres of production medium were prepared, as in
Example 6, with the addition of 0.01% v/v Pluronic L-0101 (BASF)
antifoam. Production medium was inoculated with the secondary
pre-culture at 5% v/v and allowed to ferment in a 20 L stirred
bioreactor for 7-10 days under the conditions described in Example
8. 2-Methyl butyric acid, to a final concentration of 2 mM, was fed
to the bioreactor at 26 and 37.5 hours, leading to an overall final
concentration of 4 mM. The fermentation broth was harvested after 7
days and extracted as described in Example 8.
[0216] The oily residue was dissolved in methanol (1.5 mL) and
initially chromatographed as described in Example 8. Fractions from
the initial separation that contained 21-desethyl-21-iso-propyl
spinosyn A were combined and the solvent removed in vacuo. The
residues were chromatographed over reversed-phase silica gel
(Prodigy C.sub.18, 5 .mu.m; 10.times.250 mm) eluting with a
gradient as described below, at a flow rate of 5 mL/min.
[0217] T=0, 55% B; T=5, 70% B; T=35, 95% B; T=45, 95% B.
[0218] Fractions were collected every 30 seconds. Fractions
containing the 21-desethyl-21-iso-propyl spinosyn A were combined,
the acetonitrile removed in vacuo, and the sample concentrated
using C.sub.18-BondElute cartridges (200 mg). The sample was
applied under gravity, washed with water (10 mL) and eluted with
methanol (2.times.10 mL), then the solvent was removed in
vacuo.
[0219] The dried sample was dissolved in methanol (0.5 mL) and
chromatographed over reversed-phase base-deactivated silica gel
(hypersil-C18-BDS; 4.6.times.250 mm; 5 .mu.m). The column was
eluted isocratically at a flow rate of 1 mL/min with ammonium
acetate (10 mM)--methanol--tetrahydrofuran (40:45:15), and the
three major components were collected after UV detection (244 nm).
Under these conditions, retention times were as follows:
spinosyn-D: 64.4 min., 21-desethyl-21-iso-propyl spinosyn A: 67.8
mins and 21-desethyl-21-n-propyl spinosyn A: 75.3 min. Each sample
was dried in vacuo to give a white solid, which was identified by
its NMR and mass spectra.
[0220] 21-desethyl-21-n-propyl spinosyn A (Compound 23) has the
following characteristics.
[0221] Molecular Weight: 745
[0222] Molecular formula: C.sub.42H.sub.67NO.sub.10
[0223] UV (by diode array detection during HPLC analysis): 244
nm
[0224] Electrospray MS: m/z for [M+H]+=746.5; forosamine sugar
fragment ion at m/z=142.2.
[0225] Table 10 summarizes the .sup.1H and .sup.13C NMR chemical
shift data for 21-desethyl-21-n-propyl spinosyn A in
CDCl.sub.3.
10 TABLE 10 Position .sup.1H .sup.13C 1 -- 172.5 2a 3.13 34.1 2b
2.42 -- 3 3.03 47.5 4 3.50 41.5 5 5.81 128.8 6 5.89 129.3 7 2.19
41.1 8a 1.94 36.2 8b 1.35 -- 9 4.32 76.0 10a 2.29 37.3 10b 1.35 --
11 0.92 45.9 12 2.88 49.4 13 6.78 144.1 14 -- 147.5 15 -- 202.9 16
3.30 47.6 16-Me 1.20 16.2 17 3.65 80.6 18 1.55 34.3 18b 1.55 -- 19a
1.78 21.6 19b 1.21 -- 20a 1.56 30.7 20b 1.50 -- 21 4.77 75.3 22a
1.50 37.8 22b 1.39 -- 23 1.28 18.3 24 0.99 14.0 1' 4.88 95.4 2'
3.51 77.7 3' 3.49 81.0 4' 3.13 82.2 5' 3.56 67.9 6' 1.30 19.0
2'-OMe 3.51 59.0 3'-OMe 3.51 57.7 4'-OMe 3.57 60.9 1" 4.43 103.5
2"a 1.99 30.9 2"b 1.49 -- 3"a 1.38 18.5 3"b 1.50 -- 4" 2.25 64.8 5"
3.49 73.5 6" 1.28 17.8 4"-NMe.sub.2 2.26 40.6 Chemical shifts
referenced to the proton of CHCl.sub.3 at 7.26 ppm
[0226] 21-desethyl-21-iso-propyl spinosyn A (Compound 9) has the
following characteristics.
[0227] Molecular Weight: 745
[0228] Molecular formula: C.sub.42H.sub.67NO.sub.10
[0229] UV (by diode array detection during HPLC analysis): 244
nm
[0230] Electrospray MS: m/z for [M+H]+=746.5; forosamine sugar
fragment ion at m/z=142.2.
[0231] Table 11 summarizes the .sup.1H and .sup.13C NMR chemical
shift data for 21-desethyl-21-iso-propyl spinosyn A in
CDCl.sub.3.
11 TABLE 11 Position .sup.1H .sup.13C 1 -- 173 2a 3.15 34 2b 2.43
-- 3 3.03 48 4 3.55 42 5 5.82 129 6 5.90 129 7 2.19 42 8a 1.94 36
8b 1.35 -- 9 4.32 76 10a 2.28 37 10b 1.38 11 0.93 46 12 2.90 50 13
6.78 144 14 -- 147 15 -- 204 16 3.28 48 16-Me 1.19 16 17 3.63 81 18
1.52 35 18b 1.52 -- 19a 1.80 22 19b 1.19 -- 20a 1.52 27 20b 1.52 --
21 4.66 80 22 1.80 33 23 0.85 18 22-Me 0.83 18 1' 4.87 96 2' 3.51
78 3' 3.47 81 4' 3.13 82 5' 3.56 68 6' 1.30 19 2'-OMe 3.51 59
3'-OMe 3.51 58 4'-OMe 3.58 61 1" 4.43 104 2"a 1.99 31 2"b 1.49 --
3"a 1.38 19 3"b 1.50 -- 4" 2.25 65 5" 3.49 74 6" 1.28 18
4"-NMe.sub.2 2.26 41 Chemical shifts referenced to the proton of
CHCl.sub.3 at 7.26 ppm; 13C data from 2D experiments.
[0232] Fractions from the initial fractionation that contained the
putative 21-desmethyl-21-sec-butyl spinosyn A were combined, the
acetonitrile removed in vacuo, and concentrated using
C.sub.18-BondElute cartridges (200 mg). The sample was applied
under gravity, washed with water (10 mL) and eluted with methanol
(2.times.10 mL), then the solvent removed in vacuo.
[0233] The putative 21-desmethyl-21-sec-butyl spinosyn A (Compound
11) has the following characteristics.
[0234] Molecular Weight: 759
[0235] Molecular formula: C.sub.43H.sub.69NO.sub.10
[0236] UV (by diode array detection during HPLC analysis): 244
nm
[0237] Electrospray MS: m/z for [M+H]+=760.5; forosamine sugar
fragment ion at m/z=142.2.
Coexpression of S. cinnamonensis Crotonyl-CoA Reductase
[0238] In another aspect, the invention provides engineered S.
spinosa hosts which present an altered substrate supply such that
the native polyketide synthase produces novel products. For
Example, co-expression of the S. cinnamonensis crotonyl-CoA
reductase with the spinosyn biosynthetic pathway leads to novel
products where the loading module additionally incorporates ethyl
malonyl-CoA to yield 21-desethyl-21-n-propyl spinosyns A and D, and
the AT of module 8 additionally incorporates ethyl malonyl-CoA to
yield 6-ethyl spinosyn A. In addition, both of these AT domains can
accept ethyl malonyl-CoA to yield 6-ethyl-21-desethyl-21-n-propyl
spinosyn.
[0239] The spinosyn loading module comprises a KSqAT0ACP0 which
predominantly decarboxylates methyl malonyl-CoA to incorporate
propionate. Loading modules containing a KSq are generally more
specific than those that lack them. It is therefore interesting and
unusual that the spinosyn loading module occasionally accepts
malonyl-CoA (naturally producing trace amounts of spinosyn E) and,
as disclosed here, unexpectedly accepts ethyl malonyl-CoA when it
is present.
[0240] For evidence supporting this concept see Example 18 and the
discussion immediately preceding Example 22.
Hybrid spinosyn PKS with Heterologous Extension Modules
[0241] In another of its aspects the invention provides hybrid
spinosyn PKSs comprising a heterologous extension module or a
spinosyn extension module with a heterologous AT domain.
[0242] The AT domains select the extender units that are
incorporated into the growing polyketide chain. In spinosyn
biosynthesis, the extender is predominantly malonyl-CoA. However,
the AT in module 3 is essentially specific for methyl malonyl-CoA.
It occasionally incorporates malonyl-CoA, leading to the
accumulation of spinosyn F as a natural minor component. The AT in
module 8 shows a relaxed specificity, incorporating predominantly
malonyl-CoA (to give spinosyn A) but also incorporating a
significant amount methyl malonyl-CoA (to give about 15% spinosyn
D). The amino acid sequence of the module 8 AT is similar to other
AT domains in regions that are associated with the selection of
methyl malonyl-CoA. We suggest therefore that the incorporation of
predominantly malonyl-CoA at this position is a reflection of
substrate supply, in combination with an AT domain that has an
unusually loose specificity. The AT of the loading module is
largely selective for methyl malonyl-CoA, but incorporates
malonyl-CoA 5-10% of the time (leading to production of the natural
minor component spinosyn E).
[0243] Replacement of an existing AT domain with a heterologous AT
domain selective for a different malonyl-CoA leads to a PKS that
will add, remove or replace a side chain on the spinosyn
polyketide. Where the heterologous AT domain can incorporate an
extender molecule which is not readily available within the cell,
accessory genes are included to provide the co-substrate (Stassi et
al. 1998). For Example, there is no obvious gene encoding a
crotonyl-CoA reductase in the genome of S. spinosa (C. Waldron,
unpublished observation) and therefore it is anticipated that the
supply of ethyl malonyl-CoA is severely limited in this
organism.
[0244] A system was constructed to allow AT swaps to be carried out
in module 3 of the spinosyn polyketide synthase. The AT of module 3
naturally incorporates methyl malonyl-CoA and introduces the
16-methyl branch in spinosyn. One way to effect an AT swap is by
replacement, which will result in a strain with the same
transcripts as in the native PKS. An alternative method is via
single integration, which places the complete plasmid sequence into
the spinosyn PKS genes and requires that a promoter be introduced
to drive the genes downstream of the integration site.
[0245] The following Examples (Examples 16-19) describe AT
domain-swap experiments which involve subcloning fragments using
the enzyme MscI. MscI is affected by dcm methylation due to the
sequences surrounding the site. Plasmids which are required to be
digested with MscI are therefore passaged through E. coli ET12567,
a dcm.sup.- strain, to generate DNA which is not methylated by
dcm.
[0246] A. Hybrid Spinosyn PKS Using Module 2AT of the rapamycin PKS
in Plance of Spinosyn Module 3 AT
[0247] Using the single integration approach, a spinosyn PKS was
generated in which the module 3 AT (specific for methyl
malonyl-CoA) was replaced by the rapamycin module 2 AT (malonyl-CoA
specific). The resulting strain was designated S. spinosa 7D23. The
PKS genes of 7D23 contain spnA, spnB and a truncated spnC under the
native spnA promoter, followed by the plasmid sequence (including
the apramycin resistance marker) and the hybrid spnC and spnD and
spnE under control of an introduced promoter. In 7D23 the
heterologous promoter used was the promoter for resistance to
pristinamycin. Alternative promoters could also be used, for
example the actI promoter with its cognate activator
actII-ORF4.
[0248] S. spinosa 7D23 produced the four predicted spinosyn
analogues, spinosyn F, spinosyn F 17-pseudoaglycone, 16-desmethyl
spinosyn D and 16-desmethyl spinosyn D 17-pseudoaglycone. The
yields were unexpectedly high, being only 3-fold lower than from a
non-engineered strain (see Table 12 within Example 20). The
spinosyn F compounds have been identified previously, as minor
components in non-engineered strains, but this manipulation of the
PKS genes resulted in a dramatic increase in their yield.
[0249] The abundance of the pseudoaglycone F may be a reflection of
a reduced activity of the forosamine glycosyl transferase for this
novel substrate. The final glycosylation occurs at C-17, so the
neighboring C-16 methyl group may be important for substrate
recognition.
EXAMPLE 16
Construction of a Vector Containing Spinosvn Module 3 AT with
Flanking Restriction Sites
[0250] See FIGS. 7a and 7b. The spinosyn module 3 AT domain was
amplified by PCR using pRHB3E11 as the template and the primers
CR322 (SEQ ID NO:12) and CR323(SEQ ID NO:13). These primers
introduce MscI and AvrII sites (bp 3-8 of SEQ ID NOS:12 and 13)
flanking the AT domain. The 973 bp PCR product was phosphorylated
and cloned into commercially-available pUC 18 which had previously
been digested with SmaI and dephosphorylated. Insert-containing
transformants were screened for orientation and sequenced. One
transformant, carrying an insert of the correct sequence in the
orientation which places the AvrII site next to the HindIII site of
the polylinker, was designated pALK6.
[0251] The flanking region downstream of the spinosyn module 3 AT
was amplified by PCR using pRHB3E11 as the template and the primers
CR324 (SEQ ID NO: 14) and CR332 (SEQ ID NO: 15). Primer CR324
introduces an AvrII site (bp 3-8 of SEQ ID NO: 14) at exactly the
same position as CR323, and CR332 binds downstream of a PstI site
which is naturally occurring in the sequence. The 1557 bp PCR
product was phosphorylated and cloned into commercially-available
pUC18 which had previously been digested with SmaI and
dephosphorylated. Insert-containing transformants were screened for
orientation and sequenced. One transformant, carrying an insert of
the correct sequence in the orientation which places the AvrII site
adjacent to the HindIII site of the polylinker, was designated
pALK9. pALK9 was digested with AvrII and PstI. The 1525 bp fragment
was gel-purified and cloned into pALK6 digested with AvrII and
PstI, to give plasmid pALK11.
[0252] pALK12 was constructed to provide a suitable polylinker for
this experiment. pALK6 was digested with NdeI and PstI and ligated
with an annealed linker of oligos CR328 (SEQ ID NO: 16) and CR329
(SEQ ID NO: 17). The linker was designed to destroy the NdeI site
and leave XbaI, EcoRV and PstI sites. Insert-containing clones were
analysed by restriction enzyme digestion and a single clone
displaying the correct pattern was designated pALK12.
[0253] The flanking region upstream of the spinosyn module 3 AT was
amplified by PCR using pRHB3E11 as the template and the primers
CR330 (SEQ ID NO: 18)and CR321 (SEQ ID NO: 19). Primer CR330
introduces an NdeI site (bp 18-23 of SEQ ID NO: 18) at the ATG
start codon of the spnC gene, and CR321 incorporates an MscI site
(bp 3-8 of SEQ ID NO: 19) at exactly the same position as CR322.
The 1729 bp PCR product was phosphorylated and cloned into
commercially-available pUC18 which had previously been digested
with SmaI and dephosphorylated. Insert-containing transformants
were screened for orientation and sequenced. One transformant,
carrying an insert of the correct sequence in the orientation which
places the MscI site adjacent to the HindIII site of the
polylinker, was designated pALK23. pALK12 was digested with PstI
and XmnI and the 601 bp cloned into PstI/XmnI digested pALK23 to
give pALK24. pALK11 was digested with PstI and MscI and the 2488 bp
fragment was ligated into the 3777 bp backbone produced by
digesting pALK24 with PstI and MscI, to give pALK25. To ensure
sufficient homology for integration, the fragment of DNA from the
PstI site (bp 39607-39612 of SEQ ID NO: 1 in U.S. Pat. No.
6,274,350 B1) to the MscI site (bp 41189-41194) was excised from
pRHB3E11 and cloned into pALK25 previously digested with PstI and
EcoRV to give pALK26.
[0254] pALK26 is the intermediate plasmid in the experiments to
generate spinosyn PKS genes with AT swaps in module 3. It contained
the spinosyn AT3 with flanking restriction sites, the upstream
region of spnC to the start codon, and a region downstream for
homologous recombination. It was missing a 407 bp MscI-MscI
fragment just upstream of the MscI site at the edge of the AT,
which has to be inserted after the AT swap has been achieved.
EXAMPLE 17
Construction of a Vector Which can be Used to Engineer the Spinosvn
Biosynthetic Pathway to Produce C-16 Desmethyl Spinosyns
[0255] See FIG. 8. Plasmid pALK39 was used to integrate into the
chromosome of S. spinosa by homologous recombination. It was
designed to incorporate the rapamycin AT2 into spinosyn module 3.
Such an engineered S. spinosa strain produced C-16 desmethyl
spinosyns and intermediates in this pathway. Plasmid pALK39 was
constructed as described below.
[0256] The rapamycin module 2 was excised from pCJR26 as an
MscI/AvrII fragment (see SEQ ID NO 20) and ligated into pALK26
which had previously been digested with MscI and AvrII, to give
pALK28. The 407 bp MscI fragment missing from this construct was
then excised from pALK24 (Example 16) and ligated into
dephosphorylated, MscI-digested pALK28. Clones were screened for
the orientation of the insert, and a single clone containing the
insert in the correct orientation was designated pALK32. pALK32
contains the required fragment to introduce the rap AT2 swap into
module 3 of S. spinosa, with an NdeI site at the start codon and a
downstream XbaI site just outside of the polyketide synthase
sequence. This region was excised as an NdeI/XbaI fragment and
cloned into pLSB3 to give pALK39. The new module 3 hybrid fragment
was thereby placed under P.sub.ptr, in a vector which can be
transferred into S. spinosa by conjugation and selected by
apramycin resistance.
EXAMPLE 18
Construction of a Vector Capable of Over-expressing a Crotonyl-CoA
Reductase
[0257] See FIG. 9. In order to address substrate supply issues,
pALK21 was constructed to over-express the crotonyl-CoA reductase
(ccr) gene from Streptomyces cinnamonensis. pALK21 was constructed
as described below.
[0258] The S. cinnamonensis ccr gene was amplified by PCR from
genomic DNA isolated from S. cinnamonensis ATCC 15413 using primers
CCRMONF (SEQ ID NO:21) and CCRMONR (SEQ ID NO:22). CCRMONF
introduces an NdeI site (bp 7-12 of SEQ ID NO:21) which
incorporates the ATG of the start codon of the gene, and CCRMONR
introduces a BamHI site (bp 6-11 of SEQ ID NO:22) downstream of the
stop codon. Amplification to obtain the ccr gene was carried out
under standard conditions using Pwo thermostable DNA polymerase.
The fragment was phosphorylated with T4 polynucleotide kinase then
cloned into commercially-available pUC18 digested with Smal and
dephosphorylated. Insert-containing plasmids were sequenced, and
one plasmid containing the correct sequence was designated pLSB46.
Plasmid pLSB46 contains the S. cinnamonensis ccr gene in the
orientation which places the introduced BamHI site adjacent to the
XbaI site of the polylinker. SEQ ID NO 23 shows the ccr gene from
the NdeI site at the start codon to the BamHI site after the stop
codon.
[0259] The ccr gene was excised as an NdeI/XbaI fragment and cloned
into the expression vector pLSB2 (Example 2) digested with NdeI and
XbaI, to give pLSB59. Plasmid pLSB59 contains the ccr gene under
control of the actI promoter, and the activator actII-ORF4. In
order to co-express the ccr gene with an engineered hybrid PKS, the
ccr-containing fragment, along with the actII-ORF4 activator and
actI promoter, was transferred into a vector containing a second
promoter (Pptr) which has restriction sites available for a hybrid
PKS gene. This was achieved as described below.
[0260] Plasmid pLSB59 was digested with NdeI, and the ends were
filled-in using the Klenow fragment of DNA polymerase I. This
blunt-end fragment was re-circularized to give pALK19. The gene and
promoter were excised from pALK19 as a Spel/Xbal fragment and
cloned into pLSB3 (Example 2) digested with SpeI. This step
destroys the XbaI site at the end of the ccr gene. The resulting
plasmid is designated pALK21. Plasmid pALK21 therefore contains the
ccr gene under P.sub.actI with unique NdeI and XbaI sites situated
for the introduction of hybrid PKS genes downstream of the ptr
promoter. pALK21 is apramycin resistant and contains an oriT for
conjugal transfer of DNA.
EXAMPLE 19
Generation of a S. spinosa Strain Harbouring a Hybrid Polyketide
Synthase Comprising the Rapamycin Module 2 AT in Place of the
Spinosyn Module 3 AT
[0261] See FIG. 11. Saccharopolyspora spinosa NRRL 18538 was
transformed by conjugation (Matsushima et al. 1994) from E. coli
S17-1 (Simon et al., 1983) with pALK39. Transformants were selected
for resistance to apramycin. A number of transformants were
screened by Southern blot analysis. A single transformant,
displaying the correct hybridization pattern to show that the
plasmid had integrated into the chromosome by homologous
recombination, was designated strain S. spinosa 7D23.
[0262] Example 20-21 hereinafter illustrate the use of S. spinosa
7D23 to produce novel spinosyns.
EXAMPLE 20
Production and Isolation of 16-desmethyl Spinosyns (Production of
Spinosyn F, Spinosyn F Pseudoaglycone, and Compounds 21 and 22)
[0263] 16-Desmethyl spinosyn A has previously been identified as
one of the family of spinosyns produced by a number of S. spinosa
strains, and designated spinosyn F (U.S. Pat. No. 6,274,350 B1).
Here we demonstrated production of spinosyn F and 16-desmethyl
spinosyn D (Compound 21) from the engineered hybrid pathway of S.
spinosa 7D23.
[0264] S. spinosa 7D23 was used to inoculate CSM medium (Hosted and
Baltz 1996; U.S. Pat. No. 5,362,634). This pre-culture was grown in
a 250 mL flask with a 30 cm spring to aid aeration, shaken at 250
rpm with a two-inch throw, at 30.degree. C. with 75% relative
humidity for 3 days. It was then used to inoculate vegetative
medium, 3.times.30 mL cultures in 250 mL flasks (Strobel and
Nakatsukasa 1993; U.S. Pat. No. 5,362,634) at 5% v/v, which was
cultured under the same conditions for a further 2 days. The
vegetative culture was used to inoculate production medium (Strobel
and Nakatsukasa 1993) at 5% v/v, 30.times.30 mL cultures in 250 mL
flasks grown under the conditions described above. The production
culture of S. spinosa 7D23 was grown for 10 days.
[0265] For the identification of metabolites, a 1 mL aliquot of
fermentation broth was analyzed by LC-MS as described in Example 5.
By comparison to authentic standards, it was clear that spinosyn F,
16-desmethyl spinosyn D, and their corresponding pseudoaglycones
were present (Table 12).
12TABLE 12 Retention time Key mass Yield Compound (min) spectral
data (m/z) (mg/l) spinosyn F 21.1 718.5 [M + H].sup.+; 142.4 102
16-desmethyl spinosyn 23.4 732.5 [M + H].sup.+; 142.3 38 D
(Compound 21) spinosyn F 17- 23.1 599.3 [M + Na].sup.+ 125
pseudoaglycone 16-desmethyl spinosyn 24.6 613.3 [M + Na].sup.+ 42 D
17-pseudoaglycone (Compound 22)
[0266] The remaining fermentation broth was clarified by
centrifugation. The cells were extracted twice with an equal volume
of methanol. The supernatant (780 mL) was adjusted to pH.about.10
with 5 N NaOH and twice extracted with ethyl acetate (3.times.500
mL). The methanol and ethyl acetate extracts were combined and the
solvents removed in vacuo to give an oily residue. The residue was
dissolved into ethyl acetate (250 mL) and extracted with 50 mM
tartaric acid (3.times.200 mL). The combined tartaric acid extracts
were adjusted to pH.about.10 with 5 N NaOH and extracted with ethyl
acetate (3.times.300 mL). The extracts were combined and the
solvent removed in vacuo to yield a brown oil (200 mg). The oil was
dissolved into methanol (1 mL) and half of this was initially
chromatographed as described in Example 8.
[0267] The major fractions from the initial separation that
contained 16-desmethyl spinosyn D and spinosyn F were combined and
the solvent removed in vacuo. The residues were chromatographed
over the same column, eluting with a gradient as described below at
a flow rate of 21 mL/min.
[0268] T=0 min, 35% B; T=35, 55% B; T=45, 55% B.
[0269] Fractions were collected every 30 seconds. Fractions
containing either 16-desmethyl spinosyn D or spinosyn F were
combined separately. Each of the combined set of fractions was then
worked up as follows: the acetonitrile removed in vacuo, and the
sample concentrated using a C.sub.18-BondElute cartridge (200 mg).
The sample was applied under gravity, washed with water (10 mL)
eluted with methanol (2.times.10 mL), and the solvent was removed
in vacuo.
[0270] 16-Desmethyl spinosyn D (Compound 21) has the following
characteristics.
[0271] Isolated yield: 4.8 mg
[0272] Molecular weight: 731
[0273] Molecular formula: C.sub.41H.sub.65NO.sub.10
[0274] UV (by diode array detection during HPLC analysis): 244
nm
[0275] Electrospray MS: m/z for MH.sup.+=732.5; forosamine sugar
fragment ion at m/z=142.4.
[0276] Accurate FT-ICR-MS: m/z for [MH].sup.+=732.4689 (requires
732.4681).
[0277] Table 13 summarizes the .sup.1H and .sup.13C NMR chemical
shift data for 16-desmethyl spinosyn D in CDCl.sub.3.
13 TABLE 13 Position .sup.1H .sup.13C 1 -- 172.3 2a 2.39 33.9 2b
3.09 -- 3 2.97 47.7 4 3.37 42.1 5 5.49 122.0 6 -- 136.3 6-Me 1.73
20.7 7 2.19 44.5 8a 1.41 34.8 8b 1.93 -- 9 4.29 75.7 10a 1.35 37.7
10b 2.26 -- 11 1.01 45.6 12 2.76 49.0 13 6.75 148.7 14 -- 145.1 15
-- 198.0 16a 2.47 45.1 16b 3.17 -- 17 4.05 74.4 18a 1.56 33.7 18b
1.56 -- 19a 1.17 21.5 19b 1.67 21.5 20a 1.51 29.7 20b 1.51 -- 21
4.65 76.9 22a 1.49 28.2 22b 1.49 -- 23 0.82 9.3 1' 4.85 95.5 2'
3.52 77.6 3' 3.46 81.1 4' 3.12 82.3 5' 3.54 67.9 6' 1.28 17.8
2'-OMe 3.51 59.1 3'-OMe 3.50 57.7 4'-OMe 3.56 61.0 1" 4.60 98.9 2"a
1.67 30.0 2"b 1.99 -- 3"a 1.70 20.5 3"b 2.16 -- 4" 3.10 64.6 5"
3.73 70.7 6" 1.47 18.6 4"-NMe.sub.2 Not seen* Not seen* Chemical
shifts referenced to the proton of 7.26 ppm. *Not seen due to trace
acid causing protonation of amine group.
[0278] Spinosyn F has the following characteristics.
[0279] Isolated yield: 5.5 mg
[0280] Molecular weight: 717
[0281] Molecular formula: C.sub.40H.sub.63NO.sub.10
[0282] UV (by diode array detection during HPLC analysis): 244
nm
[0283] Electrospray MS: m/z for MH.sup.+=718.5; forosamine sugar
fragment ion at m/z=142.4.
[0284] Accurate FT-ICR-MS: m/z for [MH].sup.+=718.4534 (requires
718.4525).
[0285] The NMR data accumulated for this compound were in agreement
with its proposed identity and with published data (U.S. Pat. No.
5,362,634).
EXAMPLE 21
Production and Isolation of 16-desmethyl Spinosyn D
17-pseudoaglycone
(Compound 22)
[0286] 16-Desmethyl spinosyn A 17-pseudoaglycone was previously
identified and is known as spinosyn F 17-pseudoaglycone. It is
found as one of the minor members of the family of spinosyns
produced by S. spinosa strains (U.S. Pat. No. 6,274,350 B1).
Described below is the process for the production of spinosyn F
17-pseudoaglycone and 16-desmethyl spinosyn D 17-pseudoaglycone
from the engineered hybrid pathway of S. spinosa 7D23.
[0287] Frozen vegetative stocks of S. spinosa 7D23 were used to
inoculate primary vegetative pre-cultures of S. spinosa 7D23 in CSM
(50 mL incubated in a 250 mL Erlenmeyer flask with spring).
Secondary pre-cultures in vegetative medium (250 mL incubated in a
2 L Erlenmeyer flask with spring) were prepared and incubated as
described in Example 8.
[0288] Four litres of production medium were prepared, as in
Example 6, with the addition of 0.01% v/v Pluronic L-0101 (BASF)
antifoam. Production medium was inoculated with the secondary
pre-culture at 5% v/v and was allowed to ferment in a 7 L stirred
bioreactor for 7-10 days at a temperature of 30.degree. C. Airflow
was set at 0.75 vvm, and impeller tip speed was controlled between
0.68 and 1.1 ms.sup.-1 in order to maintain dissolved oxygen
tension at or above 30% of air saturation.
[0289] For the identification of metabolites, a 1 mL aliquot of
fermentation broth was analyzed by LC-MS as described in Example 5.
By comparison to authentic standards, it was clear that spinosyn F,
16-desmethyl spinosyn D and their corresponding pseudoagylcones
were present (Table 14).
14TABLE 14 Retention time Key mass Compound (min) spectral data
(m/z) Spinosyn F 21.4 718.4 [M + H].sup.+; 142.4 16-desmethyl
spinosyn D 23.6 732.5 [M + H].sup.+; 142.3 (Compound 21) Spinosyn F
17-pseudoagylcone 23.2 599.3 [M + Na].sup.+ 16-desmethyl spinosyn D
17- 24.3 613.3 [M + Na].sup.+ pseudoagylcone (Compound 22)
[0290] The remaining fermentation broth was clarified by
centrifugation. The cells were twice extracted with an equal volume
of methanol. The supernatant (3.2 L) was extracted with ethyl
acetate (2.times.1.5 L). The methanol and ethyl acetate extracts
were combined and the solvent removed in vacuo. The residual oil
was dissolved into ethyl acetate (1 L) and washed with 50 mM
tartaric acid (3.times.500 mL). The remaining ethyl acetate
solution was evaporated in vacuo. The resulting oil was
chromatographed over flash silica gel (6.times.13 cm) eluting with
5% methanol in chloroform. Fractions of 10 mL volume were
collected. The fractions containing pseudoagylcones were combined
and the solvent removed in vacuo to yield a brown oil. The brown
oil was dissolved into methanol (1.5 mL) and chromatographed over
base-deactivated reversed-phase silica gel as described in Example
8. Fractions were collected every 30 seconds and those containing
the relevant products were combined, the acetonitrile was removed
in vacuo and the sample concentrated using C.sub.18-BondElute
cartridges (200 mg). The sample was applied under gravity, washed
with water (10 mL), eluted with methanol (2.times.10 mL), and the
solvent removed in vacuo.
[0291] 16-desmethyl spinosyn D 17-pseudoagylcone (Compound 22) had
the following characteristics:
[0292] Isolated yield: 3.3 mg
[0293] Molecular weight: 590
[0294] Molecular formula: C.sub.33H.sub.50O.sub.9
[0295] UV (by diode array detection during HPLC-MS analysis): 240
nm
[0296] Electrospray MS: m/z for [M+Na].sup.+=613.3
[0297] Accurate FT-ICR-MS: m/z for [M+H].sup.+=591.3517 (requires:
591.3528).
[0298] Table 15 summarizes the .sup.1H and .sup.13C NMR spectral
data for 16-desmethyl spinosyn D 17-pseudoagylcone in
CDCl.sub.3.
15 TABLE 15 Position .sup.1H .sup.13C 1 -- 172.5 2a 2.40 34.0 2b
3.13 -- 3 2.97 47.7 4 3.37 42.4 5 5.49 122.1 6 -- 136.3 6-Me 1.73
20.7 7 2.19 44.5 8a 1.42 34.5 8b 1.93 -- 9 4.30 75.6 10a 1.36 37.7
10b 2.28 -- 11 1.03 45.6 12 2.76 48.9 13 6.77 148.0 14 -- 145.1 15
-- 197.8 16a 2.56 47.5 16b 3.21 -- 17 4.18 68.2 18a 1.58 35.7 18b
1.58 -- 19a 1.20 21.1 19b 1.60 -- 20a 1.45 30.5 20b 1.56 -- 21 4.68
76.3 22a 1.50 28.0 22b 1.50 -- 23 0.83 9.4 1' 4.86 95.5 2' 3.51
77.7 3' 3.46 81.1 4' 3.12 82.3 5' 3.54 67.9 6' 1.28 17.8 2'-OMe
3.51 59.0 3'-OMe 3.51 57.7 4'-OMe 3.56 60.9
[0299] b. Hybrid Spinosyn PKS Using 5 AT Module of the Tylosin PKS
in Place of Spinosyn Module 3 AT
[0300] In an analogous way, a hybrid spinosyn PKS was generated in
which the methyl malonyl-CoA specific AT domain of module 3 was
replaced by the ethyl malonyl-CoA specific AT domain of tylosin
module 5 (SEQ ID NO:26). The producing strain was designated S.
spinosa 36P4. Ethyl malonyl-CoA was not expected to be abundant in
S. spinosa, so the S. cinnamonensis gene encoding crotonyl-CoA
reductase was expressed in the same cell, under control of the actI
promoter. This should significantly increase the intracellular pool
of butyryl-CoA, which is a substrate for short chain fatty acid
carboxylases that can provide ethyl malonyl-CoA. The PKS of S.
spinosa 36P4 contained spna, spnB and a truncated spnC under the
native spnA promoter, followed by the plasmid DNA including the
apramycin resistance marker. The S. cinnamonensis crotonyl-CoA
reductase under the actI promoter, and the actII-ORF4 activator,
were also within the plasmid sequence. This was followed by the
hybrid spnC (spnC*) gene under control of the promoter for
resistance to pristinamycin. One skilled in the art will appreciate
that the heterologous promoters could be swapped around, or indeed
that a number of other promoters could be chosen.
[0301] Strain S. spinosa 36P4 produced minor components which had
the UV absorbance, chromatographic properties, masses and
fragmentation patterns consistent with the expected
16-desmethyl-16-ethyl spinosyns A and D. The major products from S.
spinosa 36P4 were spinosyns A and D. Surprisingly, the predominant
novel fermentation products of strain 36P4 were
21-desethyl-21-n-propyl spinosyn A and 6-ethyl spinosyn A.
21-desethyl-21-n-propyl spinosyn A was produced at levels within
10% of that of spinosyn D. These compounds were isolated and fully
characterized by MS and NMR. We suggest that they were made due to
an increase in the intracellular concentration of ethyl
malonyl-CoA, which resulted from the introduction of the
crotonyl-CoA reductase gene. The low specificity of both the
loading AT and the module 8 AT allowed this novel substrate to be
incorporated. 6-Ethyl-21-desethyl-21-n-propyl spinosyn A was also
made by S. spinosa 36P4, as a minor factor. These three products
each have a methyl group at C16, which implies that the tylosin
module 5 AT, in this system, predominantly incorporated
methylmalonyl-CoA. It is therefore expected that a non-engineered
spinosyn PKS (with the native AT3) would produce the 21-n-propyl
and 6-ethyl spinosyn comounds in the presence of the ccr gene.
EXAMPLE 22
Construction of a Vector Which can be Used to Engineer the Spinosyn
Biosynthetic Pathway to Produce 16-desmethyl-16-ethyl Spinosyns
[0302] See FIG. 10. Plasmid pTB4 is a pUC18-based plasmid
containing a BamHI fragment of the tylosin PKS that includes most
of the tylosin module 4. The insert is from the BamHI site between
bp 24125 and 24130 of the deposited sequence tylG.embo, accession
number U78289 (at the beginning of KS4) and the BamHI site between
bp 31597 and 31612 (at the beginning of KS5).
[0303] The tylosin module 5 AT was amplified by PCR using the
template pTB4 and the primers AK1 (SEQ ID NO:24) and AK2 (SEQ ID
NO:25). The primer AK1 introduces an MscI site (bp 3-8 of SEQ ID
NO:24) at the beginning of the AT domain and primer AK2 introduces
an AvrII site (bp 3-8 of SEQ ID NO:25) at the end of the AT domain.
The PCR reaction was carried out under standard conditions using
Pwo thermostable DNA polymerase. The fragment was phosphorylated
with T4 polynucleotide kinase and cloned into
commercially-available PUC18 digested with SmaI and
dephosphorylated. Insert-containing plasmids were analysed for the
orientation of the insert and sequenced. One plasmid containing the
correct sequence was identified and designated pALK17. It contains
the PCR fragment in the orientation which places the MscI site
adjacent to the HindIII site of the polylinker. The tyl AT5 was
excised from pALKI 7 as an MscI/AvrII fragment and cloned into
pALK26 digested with MscI and AvrII to give pALK27. The 407 bp MscI
fragment which is missing from this construct was excised from
pALK24 (Example 16) and ligated into dephosphorylated,
MscI-digested pALK27. A single clone containing the insert in the
correct orientation was designated pALK31. pALK31 contains the
required fragment to introduce the tyl AT5 swap into module 3 of S.
spinosa, with an NdeI site at the start codon and a XbaI site just
downstream of the polyketide synthase sequence. This fragment was
excised as an NdeI/XbaI fragment and cloned into pALK21 to give
pALK36. This places the new module 3 hybrid fragment under
P.sub.ptr, in a vector which co-expresses the ccr from the actI
promoter, and can be transferred into S. spinosa by conjugation and
selected for apramycin resistance.
EXAMPLE 23
Generation of a S. spinosa Strain Harbouring a Hybrid Polyketide
Synthase Comprising the Tylosin Module 5 AT in Place of the
Spinosyn Module 3 AT, and Providing the Appropriate Ethyl
Malonyl-CoA Co-substrate
[0304] See FIG. 12. Saccharopolyspora spinosa NRRL 18538 was
transformed with pALK36. Transformants were selected for resistance
to apramycin and screened by Southern blot analysis. A single
transformant was designated strain S. spinosa 36P4.
EXAMPLE 24
Production and Isolation of Compounds from S. spinosa 36P4
[0305] Frozen vegetative stocks of S. spinosa 36P4 were inoculated
into primary vegetative pre-cultures of S. spinosa 36P4 in CSM (50
mL incubated in a 250 mL Erlenmeyer flask with spring). Secondary
pre-cultures in vegetative medium (250 mL incubated in a 2 L
Erlenmeyer flask with spring) were prepared and incubated as
described in Example 8.
[0306] Fourteen litres of production medium were prepared, as in
Example 6, with the addition of 0.01% v/v Pluronic L-0101 (BASF)
antifoam. Production medium was inoculated with the secondary
pre-culture at 5% v/v and was allowed to ferment in a 20 L stirred
bioreactor for 7-10 days under conditions described in Example
8.
[0307] For the identification of metabolites, a 1 mL aliquot of
fermentation broth was analyzed by LC-MS as described in Example 5.
By comparison to authentic standards, and to a fermentation extract
from strain S. spinosa NRRL 18538, the presence of new spinosyn
metabolites was verified (Table 16). The major new component eluted
with a similar--but different--retention time to spinosyn D and had
an identical mass; this compound is identified below as
21-desethyl-21-n-propyl spinosyn A. The second significant new
component eluted later and had a mass 14 units higher than spinosyn
D; this compound is identified below as 6-ethyl spinosyn A. The
third significant peak eluted later still and had a mass 28 units
higher than spinosyn D; this compound is believed to be
6-ethyl-21-desethyl-21-n-propyl spinosyn A. The mass spectra of all
of these compounds displayed a [M+H].sup.+ ion plus the forosamine
fragment. In addition, several other new components were clearly
present but were present in minor quantities. One of these new
components eluted after the first major new component and had an
identical mass to spinosyn D; this compound was probably
16-desmethyl-16-ethyl spinosyn A. Other minor new components
displayed a [M+H].sup.+ ion 14 mass units higher than spinosyn D
and a mass consistent with the forosamine fragment. One of these
new minor components may be 16-desmethyl-16-ethyl spinosyn D.
16TABLE 16 Compound Retention No. time Key mass Compound (See Table
3) (min) spectral data (m/z) 21-desethyl-21-n- 23 25.4 746.5 [M +
H].sup.+; 142.3 propyl spinosyn A 6-ethyl spinosyn A 24 27.1 760.5
[M + H].sup.+; 142.4 6-ethyl-21-desethyl- 25 29.1 774.5 [M +
H].sup.+; 142.3 21-n-propyl spinosyn A 16-desmethyl-16- 26 26.4
746.5 [M + H].sup.+; 142.3 ethyl spinosyn A putative 16- 27 26.7
760.4 [M + H].sup.+; 142.4 desmethyl-16-ethyl spinosyn D putative
16- 27 27.3 760.4 [M + H].sup.+; 142.4 desmethyl-16-ethyl spinosyn
D putative 16- 27 27.5 760.5 [M + H].sup.+; 142.3
desmethyl-16-ethyl spinosyn D
[0308] The remaining fermentation broth (12 L) was clarified by
centrifugation and extracted as described in Example 8. The residue
was dissolved into methanol (10 mL), water (2 mL) and formic acid
(100 .mu.l). The whole sample was filtered and applied under
gravity to a C.sub.18-BondElute SPE cartridge (70 g, 150 mL). The
cartridge was then developed with an increasing 10%-stepwise
gradient of acetonitrile in water (100 mL each step) containing
formic acid at 0.1% using a FlashMaster Personal system (Jones
Chromatography, Wales UK). The column was finally washed with
methanol (2.times.100 mL). Fractions containing spinosyn-like
molecules with a mass of 746 amu or greater were combined and the
solvents removed in vacuo. The residual oil (3 mL) was dissolved in
methanol (1.5 mL). This sample was initially chromatographed in two
equal portions as described in Example 8.
[0309] The fractions from the initial pair of separations that
contained 6-ethyl spinosyn A and 21-desethyl-21-n-propyl spinosyn D
(m/z=760) were combined and the solvent removed in vacuo. The
residue was dissolved in methanol (1 mL) and chromatographed over
reversed-phase silica gel (Hypersil C.sub.18-BDS, 5 .mu.m;
21.times.250 mm) eluting with a gradient as described below, at a
flow rate of 21 mL/min.
[0310] T=0 min, 40% B; T=80, 50% B.
[0311] Fractions were collected every 30 seconds. Fractions
containing predominantly 6-ethyl spinosyn A were combined, the
acetonitrile removed in vacuo, and the sample concentrated using a
C.sub.18-BondElute cartridge (200 mg), washed with water (10 mL)
and eluted with methanol (2.times.10 mL), and the solvent removed
in vacuo. Fractions from the initial pair of separations that
contained mainly 21-desethyl-21-n-propyl spinosyn A (m/z=746) were
combined and the solvent removed in vacuo. The residues were
dissolved in methanol:water (7:3, 1 mL) and chromatographed over
the same column eluting with the following gradient at 21
mL/min.
[0312] T=0 min, 40% B; T=45, 80% B.
[0313] Fractions were collected ever 30 seconds. Fractions
containing only 21-desethyl-21-n-propyl spinosyn A were combined.
Samples containing a mixture of this compound with spinosyn D were
combined separately, the solvent removed in vacuo, and the residue
chromatographed once again as described above. The fractions
containing only 21-desethyl-21-n-propyl spinosyn A were then
combined with those from the first run. The fractions containing a
mixture of the two compounds were combined and another round of
chromatography performed.
[0314] The fractions from the three runs that contained only
21-desethyl-21-n-propyl spinosyn A were combined, the acetonitrile
removed in vacuo and the sample concentrated using a
C.sub.18-BondElute cartridge (200 mg). The sample was applied under
gravity, washed with water (10 mL), eluted with methanol
(2.times.10 mL), and the solvent removed in vacuo.
[0315] 6-Ethyl spinosyn A (Compound 24) has the following
characteristics.
[0316] Isolated yield: 4.8 mg
[0317] Molecular weight: 759
[0318] Molecular formula: C.sub.43H.sub.69NO.sub.10
[0319] UV (by diode array detection during HPLC analysis): 244
nm
[0320] Electrospray MS: m/z for MH.sup.+=760.5; forosamine sugar
fragment ion at m/z=142.4.
[0321] Accurate FT-ICR-MS: m/z for [MNa].sup.+=782.4818 (requires
782.4814).
[0322] Table 17 summarizes the .sup.1H and .sup.13C NMR chemical
shift data for 6-ethyl spinosyn A in CDCl.sub.3.
17 TABLE 17 Position .sup.1H .sup.13C 1 -- 172.6 2a 2.42 34.0 2b
3.13 -- 3 2.97 47.9 4 3.44 41.9 5 5.46 120.3 6 -- 141.8 7 2.23 44.4
8a 1.42 34.5 8b 1.95 -- 9 4.30 75.8 10a 1.35 37.7 10b 2.26 -- 11
1.00 45.9 12 2.77 49.1 13 6.76 147.7 14 -- 144.4 15 -- 202.9 16
3.28 47.7 17 3.63 80.6 18a 1.52 34.3 18b 1.52 -- 19a 1.20 21.7 19b
1.77 -- 20a 1.52 30.0 20b 1.52 -- 21 4.67 76.6 22a 1.49 28.4 22b
1.49 -- 23 0.82 9.3 24a 2.05 27.4 24b 2.05 -- 25 1.03 12.6 26 1.17
16.1 1' 4.85 95.5 2' 3.50 77.7 3' 3.47 81.0 4' 3.12 82.3 5' 3.55
67.9 6' 1.28 17.8 2'-OMe 3.50 59.0 3'-OMe 3.50 57.7 4'-OMe 3.56
60.9 1" 4.43 103.4 2"a 1.50 30.8 2"b 1.99 -- 3"a 1.47 18.6 3"b 1.88
-- 4" 2.28 64.9 5" 3.49 73.4 6" 1.28 19.0 4"-NMe.sub.2 2.28 40.6
Chemical shifts referenced to the proton of CHCl.sub.3 at 7.26
ppm.
[0323] 21-desethyl-21-n-propyl spinosyn D (Compound 28) has the
following characteristics.
[0324] Isolated yield: .about.1 mg
[0325] Molecular weight: 759
[0326] Molecular formula: C.sub.43H.sub.69NO.sub.10
[0327] This compound was present as the minor component in a 4:1
mixture with 6-ethyl spinosyn A. The accumulated UV and MS data for
these two compounds are indistinguishable. Using NMR methods, the
21-n-propyl spin system could be assigned from correlations
observed in the COSY spectrum of the mixture. Methyl H24
(.delta..sub.H 0.87, dd, 7.3 Hz, 7.3 Hz) was correlated to the
methylene H23 (.delta..sub.h 1.23, m). H23 was correlated to the
methylene H22 (.delta..sub.h 1.43, m) that in turn was correlated
to H21 (.delta..sub.h 4.73, m). The H21 resonance was visible as an
isolated multiplet in the .sup.1H NMR spectrum of the mixture.
[0328] 21-desethyl-21-n-propyl spinosyn A (Compound 23) has the
following characteristics.
[0329] Isolated yield: 5.1 mg
[0330] Molecular weight: 745
[0331] Molecular formula: C.sub.42H.sub.67NO.sub.10
[0332] UV (by diode array detection during HPLC analysis): 244
nm
[0333] Electrospray MS: m/z for MH.sup.+=746.5; forosamine sugar
fragment ion at m/z=142.4.
[0334] The accumulated NMR data for this compound were identical to
those described for this compound in Example 15.
[0335] Hybrid PKS genes constructed by the replacement of other AT
(acyltransferase) domains within spn extender modules can be used
to produce novel spinosyns with altered side chains at other
positions on the polyketide. For example, in analogous methods to
those described above, hybrid polyketide synthases can be
constructed to yield spinosyns in which C18 or C20 bears a side
chain other than a hydrogen (generally a methyl or ethyl). The
native AT domains that incorporate predominantly methylmalonyl-CoA
(such as spn AT3) can be replaced by heterologous domains that
preferentially incorporate malonyl-CoA (such as rapamycin AT2) or
ethylmalonyl-CoA (such as tylosin AT5). However, one skilled in the
art will recognize that donor domains or modules for these hybrid
polyketide synthases could be acquired from a variety of Type I
polyketide synthase clusters and that this is not restricted in any
way to domains or modules from erythromycin, avermectin, rapamycin
and tylosin biosynthesis.
[0336] It is also anticipated that a combination of manipulations
should lead to productive biosynthetic pathways, and spinosyns with
two or more regions of novelty.
[0337] Additional biosynthetic genes may be required to provide an
adequate supply of a precursor that is not normally incorporated
into spinosyns, such as a ccr gene to increase ethylmalonyl-CoA
supply. This genetic modification can also lead to the production
of novel spinosyns by providing an unnatural precursor that is
incorporated at other spn AT domains. The replacement of other spn
AT domains could generate hybrid PKS genes which lead to the
synthesis of spinosyns with an ethyl group at C6, or methyl or
ethyl side chains at C18 or C20. The spn PKS domains responsible
for the degree of modification of each beta-keto group (KR, DH or
ER) might also be replaced by heterologous domains to generate
hybrid PKS genes that result in spinosyns with different saturated
bonds, hydroxyl groups or double bonds.
[0338] In summary, we have demonstrated that the hybrid spinosyn
PKS genes claimed herein are useful for the production of novel,
insecticidally-active spinosyns. The hybrid genes are derived from
the spn PKS genes combined with a portion or portions of other Type
I PKS genes. The strategies described in WO 98/01546 "Polyketides
and their synthesis" were used to select the sites where the DNAs
are spliced together. The hybrid genes can be operably linked to a
heterologous promoter such as that from the actinorhodin
biosynthetic gene actI (along with the actII-ORF4 gene encoding its
cognate activator, see WO 98/01546), or from the pristinamycin
resistance gene ptr (Blanc et al., 1995). The hybrid PKS genes are
expressed in an organism which also contains the non-PKS functions
required to produce a biologically-active spinosyn. The modified
strains provided by the invention may be cultivated to provide
spinosyns using conventional protocols such as those disclosed in
U.S. Pat. No. 5,362,634.
[0339] It is contemplated that the hybrid spinosyn PKSs of the
invention can be expressed not only in Saccharopolyspora spinosa,
but also in other host organisms, for example Saccharopolyspora
erythaea, to produce insecticidally-active spinosyns. Other
prokaryotic cells belonging to the group of actinomycetes,
preferably the group of streptomycetes, are also suitable host
organsims. Streptomyces albus is a specific example.
[0340] Pesticide Activity Of New Spinosyns
[0341] The compounds claimed herein are useful for the control of
insects and mites. Included are all isomers of the compounds, and
any acid addition salts of the compounds and their isomers. Also
included are semi-synthetic derivatives made by the methods
described in U.S. Pat. No. 6,001,981 to prepare other modified
spinosyns.
[0342] The compounds show activity against a number of insects and
mites. More specifically, the compounds show activity against
members of the insect order Lepidoptera such as the beet armyworm,
tobacco budworm, codling moth and cabbage looper. They also show
activity against members of the order Coleoptera (the beetles and
weevils) and Diptera (the true flies). The compounds also show
activity against members of the order Hempitera (true bugs),
Homoptera (aphids and hoppers), Thysanoptera (thrips), Orthoptera
(cockroaches), Siphonaptera (fleas), Isoptera (termites), and
members of the Hymenoptera order Formicidae (ants). The compounds
also show activity against the two-spotted spider mite, which is a
member of the Arachnid order Acarina.
[0343] A further aspect of the present invention is directed to
methods for inhibiting an insect or mite. In one preferred
embodiment, the present invention is directed to a method for
inhibiting a susceptible insect that comprises applying to a plant
an effective insect-inactivating amount of compound in accordance
with the present invention. The claimed compounds are applied in
the form of compositions, which are also a part of this invention.
These compositions comprise an insect- or mite-inactivating amount
of compound in an inert carrier. The active component may be
present as a single claimed compound, a mixture of two or more
compounds or a mixture of any of the compounds together with the
dried portion of the fermentation medium in which it is produced.
Compositions are prepared according to the procedures and formulas
which are conventional in the agricultural or pest control art, but
which are novel and important because of the presence of one or
more of the compounds of this invention. The compositions may be
concentrated formulations, which are dispersed in water or may be
in the form of a dust, bait or granular formulation used without
further treatment.
[0344] The action of the compositions according to the invention
can be broadened considerably by adding other, for example
insecticidally, acaricidally, and/or nematocidally active,
ingredients. For example, one or more of the following compounds
can suitably be combined with the compounds of the invention:
organophosphorus compounds, carbamates, pyrethroids, acylureas,
other types of insect growth regulators and insect hormone analogs,
neonicotinoids and other nicotinics, macrolides and other
insecticidal, acaricidal, mollscicial and nematocidal compounds or
actives. WO 00/56156 on "Synergistic Insecticide Mixtures"
discloses use of certain previously known spinosyn compounds in
combination with agonists or antagonists of nicotinic acetylcholine
receptors to control animal pests. WO 00/35282 on "Combination of
Active Ingredients" discloses use of spinosad in combination with a
fungicidally active compound. WO 00/35286 on "Combinations of
Active Ingredients" discloses use of a combination of spinosad with
other compounds to control animal pests and fungi. WO 99/60856 on
"Use of Spinosyns as Soil Insecticides" discloses use of certain
previously known spinosyns for treating seeds and for application
to plants via the soil or by irrigation to control insects. WO
99/33343 on "Use of Macrolides in Pest Control" discloses use of
spinosyns to control pests in transgenic crops, use of spinosyns to
protect plant propagation material and plant organs formed at a
later time from attack by pests, and use of spinosyns to control
wood pests and molluscs. The compounds of Formula I can also be
used for these purposes.
[0345] The compounds of the present invention are also useful for
the treatment of animals to control arthropods, i.e., insects and
arachnids including various flies and fly larvae, fleas, lice,
mites, and ticks, which are pests on animals. Techniques for
delivering ectoparasiticides are well known to those skilled in the
art. In general, a present compound is applied to the exterior
surface of an animal by sprays, dips or dusts. The compounds can
also be delivered to animals using ear tags, a delivery method
disclosed in U.S. Pat. No. 4,265,876.
[0346] In yet another embodiment, the compounds can be used to
control insects and arachnids which are pests in the feces of
cattle and other animals. In this embodiment, the compounds are
administered orally and the compounds travel through the intestinal
tract and emerge in the feces. Control of pests in the feces
indirectly protects the animals from the pests.
[0347] The compounds of the invention are also useful as human
pharmaceuticals to control parasites, for example, lice. The
compounds can be used, for example, in the formulations for
controlling lice that are disclosed in WO 00/01347.
EXAMPLE 25
Demonstration that Novel Purified Spinosyns are Insecticidal
[0348] Biological activity of the compounds of the invention was
shown by a topical assay in which the compound was applied to
laboratory-reared larvae (mean weight 22 mg) at the rate of 1
microg/larva. Each compound was applied, in an acetone solution (1
mg/mL), along the dorsum of six tobacco budworm (Heliothis
virescens) larvae and six beet armyworm (Spodoptera exigua) larvae.
Treated larvae were then held for two days at 21.degree. C., 60% RH
in six-well plastic culture plates. Larvae were each supplied with
a 1 cm.sup.3 of agar-based lepidoptera diet for sustenance during
the two-day post-expbsure interval. Percent mortality was
determined at the end of a two-day period (Table 18).
18 TABLE 18 Tobacco Budworm Beet Armyworm Compound Rate Rate No.
(See (micro/ Mortality (micro/ Mortality Compound Table 3) larva)
(%) larva) (%) solvent only 0 0 0 0 21-cyclopropyl 1 1 100 1 33
21-cyclobutyl 3 1 83 1 83 21-cyclobutyl, 4 1 100 1 83 6-methyl
21-cyclobutyl, 8 1 100 1 83 5,6-dihydro 21-isopropyl 9 1 100 1 100
21-n-propyl 23 1 100 1 100
[0349] The compounds of formula (I) can be used as intermediates in
the processes disclosed in U.S. Pat. No. 6,001,981 to produce
semi-synthetic spinosyn analogues, which are also expected to have
insecticidal activity.
[0350] The U.S. patents and patent applications cited hereinabove
are hereby incorporated by reference.
References
[0351] 1) Bierman, M., Logan, R., O'Brien, K., Seno, E T., Nagaraja
Rao, R. and Schoner, B E. (1992) "Plasmid cloning vectors for the
conjugal transfer of DNA from Escherichia coli to Streptomyces spp.
" Gene 116: 43-49.
[0352] 2) Bisang, C., Long, P F., Corts, J., Westcott, J., Crosby,
J., Matharu, A L., Cox, R J., Simpson, T J., Staunton, J. and
Leadlay, P F. (1999) "A chain initiation factor common to both
modular and aromatic polyketide synthases." Nature 401:
502-505.
[0353] 3) Blanc, V., Salah-Bey, K., Folcher, M. and Thompson, C J.
(1995) "Molecular characterization and transcriptional analysis of
a multidrug resistance gene cloned from the pristinamycin-producing
organism, Streptomyces pristinaespiralis." Mol. Microbiol. 17:
989-999.
[0354] 4) Broughton, M C., Huber, M L B., Creemer, L C., Kirst, H
A. and Turner J R. (1991) "Biosynthesis of the macrolide
insecticidal compound A83543 by Saccharopolyspora spinosa."
Proceedings of Amer. Soc. Microbiol., Washington D.C.
[0355] 5) Donadio, S., Staver, M J., McAlpine, J B., Swanson, S J.
and Katz, L. (1991) "Modular organization of genes required for
complex polyketide biosynthesis." Science 252: 675-679.
[0356] 6) Donadio, S A., Stassi, D., McAlpine, J B., Staver, M J.,
Sheldon, P J., Jackson, M., Swanson, S J., Wendt-Pienkowski, E.,
Wang, Y G., Jarvis, B., Hutchinson, C R. and Katz, L. (1993)
"Recent developments in the genetics of erythromycin formation." In
Industrial microorganisms: basic and applied molecular genetics.
(Baltz, R H., Hegeman, G D. and Skatrud, P L., eds), pp. 257-265.
Amer. Soc. Microbiol, Washington D.C.
[0357] 7) Dutton, C J., Gibson, S P., Goudie, A C., Holdom, K S.,
Pacey, M S., Ruddock, J C., Bu'Lock, J D. and Richards, M K. (1991)
"Novel avermectins produced by mutational biosynthesis." J.
Antibiot. 44: 357-365.
[0358] 8) Hosted, T J. and Baltz, R H. (1996) "Mutants of
Streptomyces roseosporus that express enhanced recombination within
partially homologous genes." Microbiology 142: 2803-2813.
[0359] 9) Hunziker, D., Yu, T W., Hutchinson, C R., Floss, H G. and
Khosla, C. (1998) "Primer unit specificity in rifamycin
biosynthesis principally resides in the later stages of the
biosynthetic pathway." J Am. Chem. Soc. 12: 1092-1093.
[0360] 10) Kirst, H A., Michel, K H., Martin, J W., Creemer, L C.,
Chio, E H., Yao, R C., Nakatsukasa, W M., Boeck, L D., Occolowitz,
J L., Paschal, J W., Deeter, J B., Jones, N D. and Thompson, G D.
(1991) "A83543A-D, unique fermentation-derived tetracyclic
macrolides." Tetrahedron Letts 32: 4839-4842.
[0361] 11) Marsden, A F A., Wilkinson, B., Corts, J., Dunster, N
J., Staunton, J. and Leadlay, P F. (1998) "Engineering broader
specificity into an antibiotic-producing polyketide synthase."
Science 279: 199-202.
[0362] 12) Matsushima, P., Broughton, M C., Turner, J R. and Baltz,
R H. (1994) "Conjugal transfer of cosmid DNA from Escherichia coli
to Saccharopolyspora spinosa: effects of chromosomal insertions on
macrolide A83543 production." Gene 146: 39-45.
[0363] 13) Pacey, M S., Dirlam, J P., Geldart, R W., Leadlay, P F.,
McArthur, H A I, McCormick, E L., Monday, R A., O'Connell, T N,
Staunton, J. and Winchester, T J. (1998) "Novel erythromycins from
a recombinant Saccharopolyspora erythraea strain NRRL 2338 pIGI.
Fermentation, isolation and biological activity," J Antibiot. 51:
1029-1034.
[0364] 14) Rowe, C J., Corts, J., Gaisser, S., Staunton, J. and
Leadlay, P F. (1998) "Construction of new vectors for high-level
expression in actinomycetes," Gene 216: 215-223.
[0365] 15) Salah-Bey, K., Blanc, V. and Thompson, C J. (1995)
"Stress-activated expression of a Streptomyces pristinaespiralis
multidrug resistance gene (ptr) in various Streptomyces spp. and
Escherichia coli." Mol. Microbiol. 17: 1001-1012.
[0366] 16) Simon, R., Preifer, U. and Puihler, A. (1983) "A broad
host range mobilization system for in vivo genetic engineering:
transposon mutagenesis in Gram negative bacteria." Bio/Technology
1: 784-791.
[0367] 17) Stassi, D L., Kakavas, S J, Reynolds, K A, Gunawardana,
G., Swanson, S., Zeidner, D., Jackson, M., Liu, H., Buko, A. and
Katz, L. (1998) "Ethyl-substituted erythromycin derivatives
produced by directed metabolic engineering." Proc. Natl. Acad. Sci.
USA 95: 7305-7309.
[0368] 18) Strobel, R J. and Nakatsukasa W M. (1993) "Response
surface methods for optimizing Saccharopolyspora spinosa, a novel
macrolide producer." J Indust. Microbiol. 11: 121-127.
[0369] 19) Waldron, C., Matsushima, P., Rosteck, P R., Jr.,
Broughton, M C., Turner, J., Madduri, K., Crawford, K P., Merlo, D
J. and Baltz, R H. (2001) "Cloning and analysis of the spinosad
biosynthetic gene cluster of Saccharopolyspora spinosa." Chem.
Biol. 8: 487-499
[0370]
Sequence CWU 1
1
26 1 61 DNA Artificial Sequence Description of Artificial Sequence
oligo PRIS1 1 ggggaattca ctagtccgcg gagaaatagc gctgtacagc
gtatgggaat ctcttgtacg 60 g 61 2 68 DNA Artificial Sequence
Description of Artificial Sequence oligo PRIS2 2 gggggatccc
atatgggctc cttgtacggt gtacgggaag atactcgtac accgtacaag 60 agattccc
68 3 94 DNA Streptomyces pristinaespiralis 3 actagtccgc ggagaaatag
cgctgtacag cgtatgggaa tctcttgtac ggtgtacgag 60 tatcttcccg
tacaccgtac aaggagccca tatg 94 4 44 DNA Artificial Sequence
Description of Artificial Sequenceoligo CR311 4 cagatatcac
tagttcggac gcatatgctg caagtatcta gaac 44 5 44 DNA Artificial
Sequence Description of Artificial Sequenceoligo CR312 5 gttctagata
cttgcagcat atgcgtccga actagtgata tctg 44 6 32 DNA Artificial
Sequence Description of Artificial Sequence oligo SP28 6 aggacacata
tggcggacct gtcaaagctc tc 32 7 34 DNA Artificial Sequence
Description of Artificial Sequence oligo SP29 7 cccgctagcg
gttcgccggg cgccgcttcg ttgg 34 8 1685 DNA Saccharopolyspora
erythraea 8 catatggcgg acctgtcaaa gctctccgac agtcggactg cacaacctgg
gaggatcgtt 60 cgtccgtggc ccctgtcggg gtgcaatgaa tccgccttgc
gggcccgtgc gcgccaattg 120 cgtgcacatc tcgatcgatt tcccgatgcc
ggtgtcgaag gtgtcggggc cgcgctcgcg 180 cacgacgagc aggcggacgc
cggtccgcat cgcgcggtcg tcgtcgcctc ctcgacctcc 240 gagctgctcg
acggcctggc cgccgtcgcc gacggccggc cgcacgcctc ggtggtccgc 300
ggcgtggccc ggccgtccgc gccggtggtg ttcgtcttcc cgggccaggg cgcgcaatgg
360 gccgggatgg cgggcgaact cctcggcgag tcaagggttt tcgccgccgc
gatggacgcg 420 tgcgcgcggg cgttcgagcc cgtgaccgac tggacgctgg
cgcaggtcct ggactctccc 480 gagcagtcgc gccgcgtcga ggtcgtccag
cccgccctgt tcgcggtgca gacgtcgctg 540 gccgcgctct ggcgctcctt
cggcgtgacc cccgacgccg tggtgggcca cagcatcggc 600 gagctggccg
ccgcgcacgt gtgcggtgcg gccggtgccg ccgacgccgc gcgcgccgcc 660
gcgctgtgga gccgcgagat gattccgttg gtgggcaacg gcgacatggc agccgtcgcg
720 ctctccgccg acgagatcga gccgcgcatc gcccggtggg acgacgacgt
ggtgctggcc 780 ggggtcaacg gtccgcgctc ggttctgctg accgggtcgc
cggaaccggt cgcgcgccgg 840 gtccaggagc tctcggccga gggggtccgc
gcacaggtca tcaatgtgtc gatggcggcg 900 cactcggcgc aggtcgacga
catcgccgag gggatgcgct cggccctggc gtggttcgcg 960 cccggtggct
cggaggtgcc cttctacgcc agcctcaccg gaggtgcggt cgacacgcgg 1020
gagctggtgg ccgactactg gcgccgcagc ttccggctgc cggtgcgctt cgacgaggcg
1080 atccggtccg ccctggaggt cggtcccggc acgttcgtcg aagcgagccc
gcacccggtg 1140 ctggccgccg cgctccagca gacgctcgac gccgagggct
cctcggccgc ggtggtcccg 1200 acgctgcaac gcgggcaggg cggcatgcgg
cggttcctgc tggccgcggc ccaggcgttc 1260 accggcggcg tggccgtcga
ctggaccgcc gcctacgacg acgtgggggc cgaacccggc 1320 tctctgccgg
agttcgcgcc ggccgaggag gaagacgagc cggccgagtc cggcgtcgac 1380
tggaacgcgc caccgcacgt gctgcgcgag cggctgctcg cggtcgtcaa cggcgagacc
1440 gccgcgttgg cgggccgcga agccgacgcc gaggccacgt tccgcgagct
ggggctggac 1500 tcggtgctgg ccgcgcagct gcgcgccaag gtgagcgccg
cgatcgggcg cgaggtcaac 1560 atcgccctgc tctacgacca cccgactccg
cgtgcgctcg cggaagcact cgcggcggga 1620 accgaggtcg cacaacggga
aacccgcgcg cggaccaacg aagcggcgcc cggcgaaccg 1680 ctagc 1685 9 32
DNA Artificial Sequence Description of Artificial Sequence oligo
SP14 9 aagctagccg tgatcgggat gggctgtcgg tt 32 10 39 DNA Artificial
Sequence Description of Artificial Sequence oligo SP15 10
atagcggccg cccccagccc ccacagatcc ggtcaccaa 39 11 1694 DNA
Streptomyces avermitilis 11 catatggcgg acctgtcaaa gctctccgac
agtcggactg cacaacctgg gaggatcgtt 60 cgtccgtggc ccctgtcggg
gtgcaatgaa tccgccttgc gggcccgtgc gcgccaattg 120 cgtgcacatc
tcgatcgatt tcccgatgcc ggtgtcgaag gtgtcggggc cgcgctcgcg 180
cacgacgagc aggcggacgc cggtccgcat cgcgcggtcg tcgtcgcctc ctcgacctcc
240 gagctgctcg acggcctggc cgccgtcgcc gacggccggc cgcacgcctc
ggtggtccgc 300 ggcgtggccc ggccgtccgc gccactagtc ttcgtttttc
ccgggcaggg cccgcaatgg 360 ccgggcatgg gaagggaact tctcgacgct
tccgacgtct tccgggagag cgtccgcgcc 420 tgcgaagccg cgttcgcgcc
ctacgtcgac tggtcggtgg agcaggtgtt gcgggactcg 480 ccggacgctc
ccgggctgga ccgggtggac gtcgtccagc cgaccctgtt cgccgtcatg 540
atctccctgg ccgccctctg gcgctcgcaa ggggtcgagc cgtgcgcggt gctgggacac
600 agcctgggcg agatcgcggc agcccacgtc tcgggaggcc tgtccctggc
cgacgccgca 660 cgcgtggtga cgctttggag ccaggcacag accacccttg
ccgggaccgg cgcgctcgtc 720 tccgtcgccg ccacgccgga tgagctcctg
ccccgaatcg ctccgtggac cgaggacaac 780 ccggcgcggc tcgccgtcgc
agccgtcaac ggaccccgga gcacagtcgt ttccggtgcc 840 cgcgaggccg
tcgcggacct ggtggccgac ctcaccgccg cgcaggtgcg cacgcgcatg 900
atcccggtgg acgttcccgc ccactccccc ctgatgtacg ccatcgagga acgggtcgtc
960 agcggcctgc tgcccatcac cccacgcccc tcccgcatcc ccttccactc
ctcggtgacc 1020 ggcggccgcc tcgacacccg cgagctagac gcggcgtact
ggtaccgcaa catgtcgagc 1080 acggtccggt tcgagcccgc cgcccggctg
cttctgcagc aggggcccaa gacgttcgtc 1140 gagatgagcc cgcacccggt
gctgaccatg ggcctccagg agctcgccgc ggacctgggc 1200 gacaccaccg
gcaccgccga caccgtgatc atgggcacgc tgcgccgcgg ccagggcacc 1260
ctggaccact tcctgacgtc tctcgcccaa ctacgggggc atggtgagac gtcggcgacc
1320 accgtcctct cggcacgcct gaccgcgctg tcccccacgc agcagcagtc
gctgctcctg 1380 gacctggtgc gcgcccacac catggcggtg ctgaacgacg
acggaaacga gcgcaccgcg 1440 tcggatgccg gcccatcggc gagtttcgcc
cacctcggct tcgactccgt catgggtgtc 1500 gaactgcgca accgcctcag
caaggccacg ggcctgcggt tgcccgtgac gctcatcttc 1560 gaccacacca
cgccggccgc ggtcgccgcg cgccttcgga ccgcggcgct cggccacctc 1620
gacgaggaca ccgcgcccgt accggactca cccagcggcc acggaggcac ggcagcggcg
1680 gacgacccgc tagc 1694 12 33 DNA Artificial Sequence Description
of Artificial Sequence oligo CR322 12 aatggccagg gctggcagtg
ggccggtatg gca 33 13 31 DNA Artificial Sequence Description of
Artificial Sequence oligo CR323 13 aacctaggaa cgccacggcc cagtccacgg
t 31 14 29 DNA Artificial Sequence Description of Artificial
Sequence oligo CR324 14 aacctaggcg cgggccgacg gctggacct 29 15 26
DNA Artificial Sequence Description of Artificial Sequence oligo
CR325 15 cgacacgcac gtctcatcct ggtcaa 26 16 29 DNA Artificial
Sequence Description of Artificial Sequence oligo CR328 16
tatcactcta gaccagatat ccagctgca 29 17 23 DNA Artificial Sequence
Description of Artificial Sequence oligo CR329 17 gctggatatc
tggtctagag tga 23 18 38 DNA Artificial Sequence Description of
Artificial Sequence oligo CR330 18 ttcctggagg gaaacgccat atgtcgaatg
aagagaag 38 19 34 DNA Artificial Sequence Description of Artificial
Sequence oligo CR321 19 tttggccagg gaagacgaag acgacctcgc cgtc 34 20
837 DNA Streptomyces hygroscopicus 20 tggccagggg tcgcagcgtg
ctggtatggg tgaggaactg gccgccgcgt tccccgtctt 60 cgcgcggatc
catcagcagg tgtgggatct gctggatgtg cccgatctcg atgtgaatga 120
gaccgggtat gcccagccgg ccctgttcgc tttgcaggtg gctctgttcg ggttgctgga
180 atcgtggggt gtacggccgg atgcggtggt cggtcactct gtcggtgagc
tcgccgccgg 240 atacgtctcc gggttgtggt cgttggagga tgcctgcact
ttggtgtcgg cgcgggctcg 300 tctgatgcag gctctgcctg cgggtggggt
gatggtcgct gtcccggtct cggaggatga 360 ggctcgggcc gtgctgggtg
agggtgtgga gatcgccgcg gtcaacgggc cgtcgtcggt 420 ggttctctcc
ggtgatgagg ccgccgtgct gcaggccgcg gaggggctgg ggaagtggac 480
gcggctggcg accagtcacg cgttccattc cgcccgtatg gaaccgatgc tggaggagtt
540 ccgggcggtc gctgaaggcc tgacctaccg gacgccgcag gtcgccatgg
ccgctggtga 600 tcaggtgatg accgctgagt actgggtgcg gcaggtccgg
gacacggtcc ggttcggcga 660 gcaggtggcc tcgttcgagg atgcggtgtt
cgtcgagctg ggtgccgacc ggtcactggc 720 ccgcctggtc gatggcatcg
cgatgctgca cggtgaccat gaggcgcagg ccgctgtcgg 780 tgccctggct
cacctgtacg tgaacggcgt gagtgtcgag tggtccgcgg tcctagg 837 21 30 DNA
Artificial Sequence Description of Artificial Sequence oligo
CCRMONF 21 ggcaaacata tgaaggaaat cctggacgcg 30 22 32 DNA Artificial
Sequence Description of Artificial Sequence oligo CCRMONR 22
tccgcggatc ctcagtgcgt tcagatcagt gc 32 23 1394 DNA Streptomyces
cinnamonensis 23 catatgaagg aaatcctgga cgcgattcag gcccagaccg
cgaccgcgag cggcaccgcc 60 gcggtcacgt ccgccgactt cgccgctctc
cccctgcccg actcgtaccg cgcgatcacc 120 gtgcacaagg acgagacgga
gatgttcgcg ggcctcgagt cccgtgacaa ggacccccgc 180 aagtcgctcc
atctggacga cgtgccgatc cccgaactcg gccccggtga ggccttggtg 240
gccgtcatgg cctcctcggt caactacaac tccgtgtgga cctcgatctt cgagcccgtc
300 tccaccttca gcttcctgga gcggtacggc cggctcagcg acctgagcaa
gcgccacgac 360 ctgccgtacc acatcatcgg ctccgacctg gcgggcgtcg
tgctgcgcac cgggcccggc 420 gtgaacgcct ggaacccggg cgacgaggtc
gtcgcgcact gcctgagcgt cgagctggag 480 tcctccgacg gccacaacga
cacgatgctc gaccccgagc agcgcatctg gggcttcgag 540 accaacttcg
gcggtctcgc cgagatcgcg ctcgtcaagt ccaaccagct catgccgaag 600
cccggtcacc tgagctggga ggaggccgcc tcgcccggcc tggtgaactc caccgcgtac
660 cgccagctgg tgtcccgcaa cggcgccggc atgaagcagg gcgacaacgt
gctgatctgg 720 ggcgcgagcg gcggactcgg gtcgtacgcc acgcagttcg
cgctcgccgg cggcgccaac 780 cccatctgtg tcgtctccag cccccagaag
gcggagatct gccgcgcgat gggcgccgag 840 gcgatcatcg accgcaacgc
cgagggctac aagttctgga aggacgagca gacccaggac 900 cccaaggagt
ggaagcgctt cggcaagcgc atccgcgagc tcaccggcgg cgaggacatc 960
gacatcgtct tcgagcaccc cggccgcgag accttcggcg cctcggtcta cgtcacgcgc
1020 aagggcggca ccatcaccac ctgcgcctcg acctcgggct acatgcacga
gtacgacaac 1080 cgctacctgt ggatgtccct gaagcgcatc atcggctcgc
acttcgccaa ctaccgcgag 1140 gcgtgggagg ccaaccgcct gatcgccaag
ggcaagatcc acccgacgct ctccaagacg 1200 taccgcctgg aggacaccgg
ccaggccgcc tacgacgtcc accgcaacct ccaccagggc 1260 aaggtcggcg
tcctcgccct cgcgcccgag gagggcctgg gcgtgcgcga cccggagaag 1320
cgggcccagc acatcgacgc gatcaaccgt ttccgcaacg tctgaacgca ctgatctgaa
1380 cgcactgagg atcc 1394 24 34 DNA Artificial Sequence Description
of Artificial Sequence oligo AK1 24 aatggccagg gctcgcagtg
gccgtcgatg gccc 34 25 36 DNA Artificial Sequence Description of
Artificial Sequence oligo AK2 25 ttcctaggaa gagggcttct ccgtcgatct
ccagtc 36 26 972 DNA Streptomyces fradiae 26 tggccagggc tcgcagtggc
cgtcgatggc ccgggacctg ctcgaccgcg cgcccgcctt 60 ccgcgagacg
gcgaaggcct gcgacgccgc gctgagcgtc catctggact ggtccgtgct 120
cgatgtcctc caggagaagc cggacgcgcc gccgctgagc cgggtcgacg tggtgcagcc
180 cgtgctgttc acgatgatgc tgtcgctcgc cgcctgctgg cgggacctcg
gcgtccaccc 240 ggccgccgtg gtgggccact cccagggaga gatcgcggcg
gcctgcgtgg ccggcgcgct 300 ctccctggag gacgcggcgc ggatcgtggc
gctgcgcagc cgggcatggc tcacactggc 360 cggcaagggc ggcatggccg
ccgtctccct gccggaagcc cggctgcgcg agcggatcga 420 gcggttcggg
cagcggctgt cggtggccgc ggtgaacagc ccgggcacgg cggcggtcgc 480
cggtgacgtg gacgcgctgc gggaactgct ggcggagctg accgcggagg gcatccgggc
540 caagccgatc cccggcgtgg acacggccgg ccactccgcg caggtggacg
gcctgaagga 600 gcatctcttc gaggtgctgg cgccggtctc cccgcgctcc
tcggacatcc cgttctactc 660 gacggtgacg ggcgcgccgc tggacaccga
gcggctggac gccgggtact ggtaccgcaa 720 catgcgggag cccgtggagt
tcgagaaggc cgtcagggca ctgatcgccg acggctacga 780 cctgttcctg
gagtgcaacc cgcacccgat gctcgccatg tcgctggacg agacactcac 840
cgacagcggc ggccacggca ccgtgatgca caccctccgc cggcagaagg gcagcgccaa
900 ggacttcggc atggcgctct gcctcgccta tgtcaacgga ctggagatcg
acggagaagc 960 cctcttccta gg 972
* * * * *