U.S. patent application number 15/393365 was filed with the patent office on 2017-05-04 for modified antibody in which motif comprising cysteine residue is bound, modified antibody-drug conjugate comprising the modified antibody, and production method for same.
This patent application is currently assigned to Alteogen Inc.. The applicant listed for this patent is Alteogen Inc.. Invention is credited to Hye-Shin Chung, Yong Mo Kim, Seonhun Kwon, Sunbae Lee, Soon Jae Park, Sun-Ah You.
Application Number | 20170119903 15/393365 |
Document ID | / |
Family ID | 49005999 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170119903 |
Kind Code |
A1 |
Park; Soon Jae ; et
al. |
May 4, 2017 |
MODIFIED ANTIBODY IN WHICH MOTIF COMPRISING CYSTEINE RESIDUE IS
BOUND, MODIFIED ANTIBODY-DRUG CONJUGATE COMPRISING THE MODIFIED
ANTIBODY, AND PRODUCTION METHOD FOR SAME
Abstract
The present invention relates to an antibody in which a motif
composed of an amino acid or peptide sequence including one or more
cysteine residues is bound to the terminus of a parent antibody,
particularly the terminus of the heavy chain of the parent
antibody. Also, the present invention relates to a modified
antibody-drug conjugate (mADC) comprising a drug bound to the
antibody, and a method for producing the antibody or the modified
antibody-drug conjugate. The modified antibody-drug conjugate
according to the invention can accurately deliver the drug to a
target cell due its high specificity to antigen, and thus can
increase the therapeutic effect of the drug. Also, it can increase
the usability of drugs, particularly anticancer drugs, the use of
which is restricted due to their toxicity, despite their high
efficacy. Moreover, the invention relates to a composition for
treatment of diseases, particularly cancers, which comprise the
modified antibody-drug conjugate.
Inventors: |
Park; Soon Jae; (Daejeon,
KR) ; Chung; Hye-Shin; (Daejeon, KR) ; Kwon;
Seonhun; (Seoul, KR) ; Lee; Sunbae; (Daejeon,
KR) ; You; Sun-Ah; (Daejeon, KR) ; Kim; Yong
Mo; (Jeollabuk-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alteogen Inc. |
Daejeon |
|
KR |
|
|
Assignee: |
Alteogen Inc.
Daejeon
KR
|
Family ID: |
49005999 |
Appl. No.: |
15/393365 |
Filed: |
December 29, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14380068 |
Aug 20, 2014 |
|
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PCT/KR13/01417 |
Feb 22, 2013 |
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15393365 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K 2317/73 20130101;
A61P 43/00 20180101; C07K 16/3015 20130101; A61K 47/65 20170801;
A61P 35/00 20180101; C07K 16/32 20130101; A61K 38/07 20130101; A61K
47/6803 20170801; C07K 2317/52 20130101; C07K 16/30 20130101; C07K
16/00 20130101; C07K 2317/76 20130101; A61K 47/6855 20170801; A61K
47/6849 20170801; A61K 31/704 20130101; C07K 2317/24 20130101; A61K
47/6851 20170801; A61K 47/6871 20170801; A61K 47/6809 20170801;
A61K 47/6817 20170801 |
International
Class: |
C07K 16/00 20060101
C07K016/00; A61K 31/704 20060101 A61K031/704; C07K 16/30 20060101
C07K016/30; C07K 16/32 20060101 C07K016/32; A61K 38/07 20060101
A61K038/07 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2012 |
KR |
10-2012-0019221 |
Claims
1. An antibody-drug conjugate comprising a modified antibody
comprising a cysteine-containing motif at the terminus of a parent
antibody, with a formula 1: Xa-[(M.sub.Cys).sub.n-Xb.sub.n].sub.n
Formula (1) wherein (M.sub.Cys).sub.n is a metal ion binding motif
that contains a cysteine residue; Xa and Xb.sub.n each
independently is a peptide comprising 0 to 20 amino acid residues
other than cysteine; and n is an integer ranging from 1 to 20, the
metal ion binding motif that contains a cysteine residue is any one
or more selected from the group consisting of: (A) a zinc finger
motif that contains C.sub.2H.sub.2 group (Cys.sub.2His.sub.2 class:
Cys-X.sub.2-4-Cys-X.sub.12-His-X.sub.3-5-His), C.sub.4 group (C4
class:
Cys-X.sub.2-Cys-X.sub.m-Cys-X.sub.2-Cys-X.sub.m-Cys-X.sub.2-Cys-X.-
sub.m-Cys-X.sub.2-Cys) or C.sub.6 group (C6 class:
Cys-X.sub.2-Cys-X.sub.6-Cys-X.sub.5-12-Cys-X.sub.2-Cys-X.sub.6-8-Cys)
of zinc finger protein, wherein each X is independently an amino
acid residue other than Cys; m is an integer ranging from 1 to 10;
and X.sub.m or X.sub.m-q of X.sub.2-4, X.sub.3-5, X.sub.5-12 or
X.sub.6-8 in the C.sub.2H.sub.2 group, C.sub.4 group, or C.sub.6
group, is m or m to q amino acid residues other than Cys; (B) a
metal ion binding motif artificially designed based on a zinc
finger motif or a metal ion binding protein motif; (C) a
Cys-X.sub.m-Cys motif, a Met-X-Cys-X-X-Cys motif, or a
C-Q-C-Q-C-A-C motif of transcription regulatory proteins, metal
chaperone proteins, metal ion transporters, or superoxide
dismutase; wherein each X is independently an amino acid residue
other than Cys; m is an integer ranging from 1 to 10; (D) a
Ser-Pro-Cys motif of membrane protein ATPase; and (E) a metal ion
binding peptide motif having a circular structure; and the drug is
conjugated to the thiol group of the cysteine residue in the metal
ion binding motif.
2. The antibody-drug conjugate of claim 1, wherein the
cysteine-containing motif is bound to the terminus of the heavy
chain of the parent antibody.
3. The antibody-drug conjugate of claim 2, wherein the
cysteine-containing motif is bound to the C-terminus of the heavy
chain of the parent antibody.
4. The antibody-drug conjugate of claim 1, comprising the metal ion
binding motif (A), wherein the C.sub.2H.sub.2 group, the C.sub.4
group or the C.sub.6 group of the zinc finger protein is any one
selected from the group consisting of TABLE-US-00007 (SEQ ID NO: 1)
YKCKQCGKAFGCPSNLRRHGRTH, (SEQ ID NO: 2) YQCNICGGKCFSCNSNLHRHQRTH,
(SEQ ID NO: 3) YSCGICGKSFSDSSAKRRHCILH, (SEQ ID NO: 4)
YTCSDCGKAFRDKSCLNRHRRTH, (SEQ ID NO: 5) YRCKYCDRSFSDSSNLQRHVRNIH,
(SEQ ID NO: 6) YKCKECGKAFNHSSNFNKHHRIH, (SEQ ID NO: 7)
FKCPVCGKAFRHSSSLVRHQRTH, (SEQ ID NO: 8) YRCKYCCDRSFSISSNLQRHVRNIH,
(SEQ ID NO: 9) YECDHCGKAFSIGSNLNVHRRIH, (SEQ ID NO: 10)
YGCHLCCKAFSKSSNLRRHEMIH, (SEQ ID NO: 11) YKCKECGQAFRQRAHLIRFIHKLH,
(SEQ ID NO: 12) YKCHQCGKAFIQSFNLRRHERTH, (SEQ ID NO: 13)
FQCNQCGASFTQKGNLNRHIKLH, (SEQ ID NO: 14) YTCSYCGKSFTQSNTLKQHTRIH,
(SEQ ID NO: 15) YACHLCGKAFTQSSHRRHEKTH, (SEQ ID NO: 16)
YKCGQCGKFYSQVSHLTRHQKIH, (SEQ ID NO: 17) YACHLCGKAFTQCSHLRRHEKTH,
(SEQ ID NO: 18) YACHLCAKAFIQCSHLRRHEKTH, (SEQ ID NO: 19)
YVCRECGRGFRQHSHLVRHKRTH, (SEQ ID NO: 20) YKCEECEGKAFRQSSHLTTHKIIH,
(SEQ ID NO: 21) YECDHCGKSFSQSSHLNVHKRTH, (SEQ ID NO: 22)
YMCSECGRGFSQKSNLTIHQRTH, (SEQ ID NO: 23) YKCEECGKAFTQSSNLTKHKKIH,
(SEQ ID NO: 24) FECKDCGKAFIQKSNLIRHQRTH, (SEQ ID NO: 25)
YVCRECRRGFSQKSNLIRHQRTH, (SEQ ID NO: 26) YECEKCGKAFNQSSNLTRHKKSH,
(SEQ ID NO: 27) YECVQCGKSYSQSSNLFRHQRRH, (SEQ ID NO: 28)
YECVQCGKGFTQSSNLITHQRVH, (SEQ ID NO: 29) YECNTCRKTFSQKSNLIVHQRTH,
(SEQ ID NO: 30) YVCSKCGKAFTQSSNLTVHQKIH, (SEQ ID NO: 31)
YKCDECGKNFTQSSNLIVHKRIH, (SEQ ID NO: 32) YECDVCGKTFTQKSNLGVHQRTH,
(SEQ ID NO: 33) YKCPDCGKSFSQSSSLIRHQRTH, (SEQ ID NO: 34)
YECQDCGRAFNQNSSLGRHKRTH, (SEQ ID NO: 35) YECNECGKFFSQSSSLIRHRRSH,
(SEQ ID NO: 36) YKCEECGKAFNQSSTLTRHKIVH, (SEQ ID NO: 37)
YECNECGKAFAQNSTLRVHQRIH, (SEQ ID NO: 38) YEVHDCGKSFRQSTHTLTQHRRIH,
(SEQ ID NO: 39) YECHDCGKSFRQSTHLTRHRRIH, (SEQ ID NO: 40)
HKCLECGKCFSQNTHLTRHQRTH, (SEQ ID NO: 41) YVCDVEGCTWKFARSDELNRHKKRH,
(SEQ ID NO: 42) YHCDWDGCGWKFARSDELTRHYRKH, (SEQ ID NO :43)
YRCSWEGCEWRFARSDELTRHFRKH, (SEQ ID NO: 44)
FSCSWKGCERRFARSDELSRHRRTH, (SEQ ID NO: 45)
FACSWQDCNKKFARSDELARHYRTH, (SEQ ID NO: 46)
YHCNWDGCGWKFARSDELTRHYRKH, (SEQ ID NO: 47)
FLCQYCAQRFGRKDHLTRHMKHSH, (SEQ ID NO: 48) CRCNECGKSFSRRDHLVRHQRTH,
(SEQ ID NO: 49) FQCKTCQRKFSRSDHLKTHTRTH, (SEQ ID NO: 50)
FACEVCGVRFTRNDKLKIHMRKH, (SEQ ID NO: 51) YVCDVEGCTWKFARSDKLNRHKKRH,
(SEQ ID NO: 52) YKCMECGKAFNRRSHLTRHQRIH, (SEQ ID NO: 53)
YICRKCGRGFSRKSNLIRHQRTH, (SEQ ID NO: 54) YECKECGKAFSSGSNFTRHQRIH,
(SEQ ID NO: 55) FHCGYCEKSFSVKDYLTKHIRTH, (SEQ ID NO: 56)
YECDHCGKAFSVSSNLNVHRRIH, (SEQ ID NO: 57) YTCKQCGKAFSVSSSLRRHETTH,
(SEQ ID NO: 58) YECNYCGKTFSVSSTLIRHQRIH, (SEQ ID NO: 59)
YRCEECGKAFRWPSNLTRHKRIH. (SEQ ID NO: 60) FACDICGRKFARSDERKRHTKIH,
(SEQ ID NO: 61) CPVESCDRRFSRSDELTRHIRIH, and (SEQ ID NO: 62)
CDICGRKFARSDERKRHTKIH.
5. The antibody-drug conjugate of claim 1, comprising the metal ion
binding motif (B), wherein the metal ion binding motif artificially
designed based on a zinc finger motif or the metal ion binding
protein motif is any one selected from the group consisting of
TABLE-US-00008 (SEQ ID NO: 86) PYKCPECGKSFSQKSALVKHQRTHTC, (SEQ ID
NO: 87) PYKCPECGKSFSQKSALVKHQRTHTM, (SEQ ID NO: 88)
PYKCPECGKSFSQKSALVKHQRTHT(Me-C), (SEQ ID NO: 89)
PYK(Me-C)PECGKSFSQKSALVKHQRTHTH, (SEQ ID NO: 90)
PYKCPE(Me-C)GKSFSQKSALVKHQRTHTH, (SEQ ID NO: 91)
PYKCPE(Me-C)GKSFSQKSALVKHQR, (SEQ ID NO: 92)
GLKALEEKCKALEEKLKALEEKLKALEEKG, (SEQ ID NO: 93)
GLKALEEKLKALEEKLKACEEKLKALEEKG, (SEQ ID NO: 94)
GLKALEEKCKALEEKLKACEEKLKALEEKG, (SEQ ID NO: 95)
GLKALEEKLKALEEKCKALEEKLKALEEKG, (SEQ ID NO: 96)
GLKALEEKLKALEEKLKALEEKCKALEEKG, (SEQ ID NO: 97)
GLKALEEKLKALEEKLKALEEKLKAAEEKCKALEEKG, (SEQ ID NO: 98)
GLKALEEKLKALEEKCKALEEKLKAAEEKCKALEEKG, (SEQ ID NO: 99)
ELYALEKELGALEKELACLEKELGALEKELYALEK, (SEQ ID NO: 100)
KLYALKEKLGALKEKLACLKEKLGALKEKLYALKE, (SEQ ID NO: 101)
ELYALEKELGALEKELACLKEKLGALKEKLYALKE, and (SEQ ID NO: 102)
KLYALKEKLGALKEKLACLEKELGALEKELYALEK.
6. The antibody-drug conjugate of claim 1, comprising the metal ion
binding motif (C), wherein the Cys-X.sub.m-Cys motif, the
Met-X-Cys-X-X-Cys motif, or the C-Q-C-Q-C-A-C motif of the
transcription regulatory proteins, the metal chaperone proteins,
the metal ion transporters, or the superoxide dismutase is any one
selected from the group consisting of
CEIFCYDEEKVNRIQGDLQTVDISGVSQILKAIADENRAKITYALCQDEELCVC (SEQ ID NO:
63), CDTHLVHLDNVRSSQAQILPTDKAQQMAEIFGVLADTNRIRLLSALASSELCVC (SEQ ID
NO: 64)), CDQPLVHLEQVRQVQPEVMSLDQAQQMAEFFSALADPSRLRLMSALARQELCV C
(SEQ ID NO: 65),
CDRAHLVDCSRVGDIQTQVLNTAKAQRMAEFFSLLGDANRLRVVSVLAKQELC VC (SEQ ID
NO: 66), LSDETRLGIVLLLREMGELCVCDLCM (SEQ ID NO: 67),
CCTLATGPLSSDESEHYADLFKVLGDPVRLRILSQLAAGGC (SEQ ID NO: 68),
YRAAMPVVRALVAYLTENCCHGTRDC (SEQ ID NO: 69),
CLRGCGLVVATYEGRQVRYALADSHLARALGELVQVVLAVDTDQPC (SEQ ID NO: 70),
CLRDCGLVVTVPDGRRSRYELADERLGHALDDLRAAVVAVDADRTCPDADELE CC (SEQ ID
NO: 71), HXXWFYLX.sub.21-28CXLFMVIGXWFLVIX.sub.18-27HXXH, wherein X
is any amino acid, and X.sub.m-q is amino acid residues other than
Cys, the number of which is indicated by m to q, TABLE-US-00009
(SEQ ID NO: 72) VSGMDCAACARKVENAVRQLAGVNQVQVLFA, (SEQ ID NO: 73)
VPGMTCSACPITVKKAISEVEGVSKVDVTFE, (SEQ ID NO: 74)
ITGMTCDSCAAHVKEALEKVPGVQSALVSY, (SEQ ID NO: 75)
VQGFTCANCAGKFEKNVKKIPGVQDAKVNFG, (SEQ ID NO: 76)
VEGMTCNSCVWTIEQQIGKVNGEHHIKVSLE, (SEQ ID NO: 77)
VVMTCSGCSGAVNKVLTKLEPDVSKIDIS, (SEQ ID NO: 78)
GMTCASCVANIERNLRREEGIYSV, (SEQ ID NO: 79)
YEGMTCQSCVSSIEGKYRKLQGVVRYKVSL, (SEQ ID NO: 80)
GMSCQGCAGAVRRVLTKMEGVETFDIDME, (SEQ ID NO: 81)
VPSITCSHCVDKIEKFVGEIEGVSFIDANVE, (SEQ ID NO: 82)
VTGMTCAACSNSVEAALMNVNGVDVGGMTCGGCSASVKKLLESQPCVASA SV, (SEQ ID NO:
83) VSGMVCAACSTAVENALLSCSGV, (SEQ ID NO: 84)
DVGGMTCGGCSASVKKILESQP, and (SEQ ID NO: 85)
DVGGMKCGGCVEHVKKILEEQFGVTSAS.
7. The antibody-drug conjugate of claim 1, comprising the metal ion
binding motif (D).
8. The antibody-drug conjugate of claim 1, comprising the metal ion
binding motif (E), wherein the metal ion binding peptide motif
having the circular structure is Cyclo[K 1,12] (QCGVCGKCIACK).
9. The antibody-drug conjugate of claim 1, wherein the parent
antibody is one or more selected from the group consisting of a
monoclonal antibody, a bispecific antibody, a chimeric antibody, a
human antibody, and a humanized antibody.
10. The antibody-drug conjugate of claim 1, wherein the parent
antibody is one or more selected from the group consisting of IgA,
IgD, IgE, IgG, and IgM.
11. The antibody-drug conjugate of claim 1, wherein the parent
antibody has binding affinity and specificity to cancer-specific
antigens, cell surface receptor proteins, cell surface proteins,
transmembrane proteins, signaling proteins, cell survival
regulators, cell proliferation regulators, molecules associated
with tissue development or differentiation, lymphokines, cytokines,
molecules involved in cell cycle regulation, molecules involved in
vasculogenesis, or molecules associated with angiogenesis.
12. The antibody-drug conjugate of claim 1, wherein the parent
antibody has binding affinity to one or more proteins selected from
the group consisting of: (1) BMPRIB (bone morphogenetic protein
receptor-type IB; (2) E16 (LAT1, SLC7A5); (3) STEAP1 (six
transmembrane epithelial antigen of prostate); (4) 0772P (CA125,
MUC16); (5) MPF (MPF, MSLN, SMR, megakaryocyte potentiating factor,
mesothelin); (6) Napi3b (NAPI-3B, NPTIIb, SLC34A2, solute carrier
family 34 (sodium phosphate), member 2, type II sodium-dependent
phosphate transporter 3b); (7) Sema 5b (FLJ10372, KIAA1445,
Mm.42015, SEMA5B, SEMAG, Semaphorin 5b Hlog, sema domain, seven
thrombospondin repeats (type 1 and type 1-like), transmembrane
domain (TM) and short cytoplasmic domain, (semaphorin) 5B); (8)
PSCA hlg (2700050C12Rik, C530008016Rik, RIKEN cDNA 2700050C12,
RIKEN cDNA 2700050C12); (9) ETBR (Endothelin type B receptor); (10)
MSG783 (RNF124, hypothetical protein FLJ20315); (11) STEAP2
(HGNC_8639, IPCA-1, PCANAP1, STAMP1, STEAP2, STMP, prostate cancer
associated gene 1, prostate cancer associated protein 1,
six-transmembrane epithelial antigen of prostate 2,
six-transmembrane prostate protein); (12) TrpM4 (BR22450, FLJ20041,
TRPM4, TRPM4B, transient receptor potential cation channel,
subfamily M, member 4); (13) CRIPTO (CR, CR1, CRGF, CRIPTO, TDGF1,
teratocarcinoma-derived growth factor); (14) CD21 (CR2 (Complement
receptor 2) or C3DR (C3d/Epstein Barr virus receptor) or Hs.73792);
(15) CD79b (CD79B, CD790, IGb (immunoglobulin-associated beta),
B29); (16) FcRH2 (IFGP4, IRTA4, SPAP1A (SH2 domain containing
phosphatase anchor protein 1a), SPAP1B, SPAP1C); (17) HER2; (18)
ErbB receptor selected from EGFR, HER3, and HER4; (19) NCA; (20)
MDP; (21) IL20R.alpha.; (22) Brevican; (23) EphB2R; (24) ASLG659;
(25) PSCA; (26)GEDA; (27) BAFF-R (B cell-activating factor
receptor, BLyS receptor, BR3); (28) CD22 (B-cell receptor CD22-B
isoform); (29) CD79a (CD79A, CD79.alpha., immunoglobulin-associated
alpha, a B cell-specific protein that covalently interacts with Ig
beta (CD79B) and forms a complex on the surface with IgM molecules,
transduces a signal involved in B-cell differentiation); (30) CXCR5
(Burkitt's lymphoma receptor 1, a G protein-coupled receptor that
is activated by the CXCL 13 chemokine, functions in lymphocyte
migration and humoral defense, plays a role in HIV-2 infection and
regarded for development of AIDS, lymphoma, myeloma, and leukemia);
(31) HLA-DOB (Beta subunit of MHC class II molecule (1a antigen)
that binds peptides and presents them to CD4+T lymphocytes); (32)
P2X5 (Purinergic receptor P2X ligand-gated ion channel 5, an ion
channel gated by extracellular ATP, may be involved in synaptic
transmission and neurogenesis, deficiency may contribute to the
pathophysiology of idiopathic detrusor instability); (33) CD72
(B-cell differentiation antigen CD72, Lyb-2); (34) LY64 (Lymphocyte
antigen 64 (RP105), type I membrane protein of the leucine rich
repeat (LRR) family, regulates B-cell activation and apoptosis,
loss of function is associated with increased disease activity in
patients with systemic lupus erythematosis); (35) FcRH1 (Fc
receptor-like protein 1, a putative receptor for the immunoglobulin
Fc domain that contains C2 type Ig-like and ITAM domains); (36)
IRTA2 (Immunoglobulin superfamily receptor translocation associated
2; (37) TENB2 (putative transmembrane proteoglycan); (38)
MAGE-C1/CT7; (39) androgen receptor, PTEN, human kallikrein-related
peptidase 3; (40) CD20; (41) CD30; (42) CD33; (43) CD52; (44)
EpCam; (45) CEA; (46) gpA33; (47) Mucins; (48) TAG-72; (49)
Carbonic anhydrase IX; (50) PSMA; (51) folate binding protein; (52)
gangliosides (GD2, GD3, GM2); (53) hydrate/saccharide Lewis-Y; (54)
VEGF; (55) VEGFR; (56) aVb3; (57) a5b1; (58) ERB3; (59) c-MET; (60)
EphA3; (61) TRAIL-R1, TRAIL-R2; (62) RANKL; (63) FAP; and (64)
Tenascin.
13. The antibody-drug conjugate of claim 1, wherein the parent
antibody comprises one or more selected from the group consisting
of trastuzumab, rituximab, bevacizumab, cetuximab, panitumumab,
ipilimumab, alemtuzumab, ofatumumab, gemtuzumab, brentuximab,
.sup.90Y-ibritumomab, .sup.131I-tositumomab, cBR96, cAClO,
anti-CD20 antibody, anti-EphB2 antibody, anti-IL-8, E-selectin
antibody, anti-MUC16 antibody, anti-CD30 antibody, anti-CD33
antibody, and anti-CD52 antibody.
14. The antibody-drug conjugate of claim 1, wherein the drug is
conjugated to the cysteine residue in the motif by a linker.
15. The antibody-drug conjugate of claim 14, wherein the linker is
one or more selected from the group consisting of alkyl halide
derivatives containing a haloacetyl group, derivatives containing a
maleimide group, aryl halide derivatives containing fluorobenzene,
aziridine derivatives and acryloyl derivatives, wherein the
derivatives comprise an alkylating reactive group, an arylating
reactive group, a maleimide group, an aziridine group, an acryloyl
group, or a disulfide exchange reactive group comprising pyridyl
disulfide or thionitrobenzoic acid, which reacts with the thiol
group of the cysteine residue in the motif and is covalently bound
thereto.
16. The antibody-drug conjugate of claim 1, wherein the drug is one
or more selected from the group consisting of microtubulin
inhibitors, mitotic inhibitors, topoisomerase inhibitors, or
chemotherapeutic agents capable of functioning as DNA
intercalators, anticancer agents, protein toxins capable of
functioning as enzymes, micro-RNA (miRNA), siRNA, or shRNA, which
can inhibit the expression of a specific oncogene, and
radioisotopes.
17. The antibody-drug conjugate of claim 1, wherein the drug is one
or more selected from the group consisting of maytansinoid,
auristatin, aminopterin, actinomycin, bleomycin, talisomycin,
camptothecin, N.sup.8-acetyl spermidine, 1-(2
chloroethyl)-1,2-dimethyl sulfonyl hydrazide, taxol, esperamicin,
etoposide, 6-mercaptopurine, dolastatin, trichothecene, CC1065,
calicheamicin and other enediyne antibiotics, taxane,
anthracycline, methotrexate, adriamycin, vindesine, vinca
alkaloids, vincristine, vinblastine, etoposide, doxorubicin,
melphalan, mitomycin A, mitomycin C, chlorambucil, daunorubicin,
daunomycin and stereoisomers, isosteres, or analogs thereof,
duocamycin and stereoisomers, isosteres, or analogs thereof,
nucleolytic enzymes, antibiotics, toxins of bacterial, plant or
animal origin, cisplatin, CPT-11, doxorubicin, paclitaxel, and
docetaxel.
18. The antibody-drug conjugate of claim 1, wherein the drug is one
or more selected from the group consisting of maytansinoid,
auristatin, aminopterin, actinomycin, bleomycin, talisomycin,
camptothecin, N.sup.8-acetyl spermidine, 1-(2
chloroethyl)-1,2-dimethyl sulfonyl hydrazide, taxol, esperamicin,
etoposide, 6-mercaptopurine, dolastatin, trichothecene, CC1065,
calicheamicin and other enediyne antibiotics, taxane,
anthracycline, methotrexate, adriamycin, vindesine, vinca
alkaloids, vincristine, vinblastine, etoposide, doxorubicin,
melphalan, mitomycin A, mitomycin C, chlorambucil, daunorubicin,
daunomycin and stereoisomers, isosteres, or analogs thereof,
duocamycin and stereoisomers, isosteres, or analogs thereof,
nucleolytic enzymes, antibiotics, toxins of bacterial, plant or
animal origin, cisplatin, CPT-11, doxorubicin, paclitaxel, and
docetaxel.
19. A therapeutic composition comprising the antibody-drug
conjugate according to claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation under 35 USC 120 of U.S. patent
application Ser. No. 14/380,068 filed Aug. 20, 2014 for MODIFIED
ANTIBODY IN WHICH MOTIF COMPRISING CYSTEINE RESIDUE IS BOUND,
MODIFIED ANTIBODY-DRUG CONJUGATE COMPRISING THE MODIFIED ANTIBODY,
AND PRODUCTION METHOD FOR SAME, which in turn is a U.S. national
phase under the provisions of 35 U.S.C. .sctn.371 of International
Patent Application No. PCT/KR2013/001417 filed Feb. 22, 2013, which
in turn claims priority of Korean Patent Application No.
10-2012-0019221 filed Feb. 24, 2012. The disclosures of all such
patent applications are hereby incorporated herein by reference in
their respective entireties, for all purposes.
TECHNICAL FIELD
[0002] The present invention relates to a modified antibody
comprising a cysteine (Cys)-containing motif bound to a parent
antibody, preferably the terminus of the parent antibody, more
preferably the terminus of the heavy or light chain of the parent
antibody, and most preferably the C-terminus of the heavy or light
chain of the parent antibody, a modified antibody-drug conjugate
(mADC) comprising a drug for diagnosis or treatment bound to the
modified antibody, and a method for producing the modified antibody
or the modified antibody-drug conjugate.
[0003] The modified antibody-drug conjugate according to the
present invention can accurately deliver the drug to a target cell
due to the high antigen specificity of the parent antibody included
in the conjugate, and thus can increase the therapeutic effect of
the drug. Also, it can increase the utility of drugs, particularly
anticancer drugs with high anticancer efficacy, the use of which is
restricted due to their toxicity.
[0004] Moreover, the present invention relates to a composition,
including the modified antibody-drug conjugates, for the treatment
of diseases, particularly cancer and to a method of treating
diseases using the modified antibody-drug conjugate.
[0005] The modified antibody-drug conjugate according to the
present invention may contain a number of cysteine residues that
can be used for conjugating to drugs, because the motif containing
one or more cysteine residues is bound to the parent antibody.
Thus, it can contain a large amount of drugs bound thereto, and the
large amount of bound drug can be effectively delivered to a target
cell or tissue. Moreover, because the number of cysteine residues
that are bound to the parent antibody can be easily controlled, the
amount of the drug contained in the modified antibody-drug
conjugate (mADC) can be easily controlled to a desired level.
[0006] In addition, because the modified antibody-drug conjugate
according to the present invention can accurately deliver the drug
to a target cell due to its high specificity to an antigen, it can
increase the therapeutic effect of the drug and can also improve
the utility of drugs, particularly anticancer drugs, which are
restricted in use due to their toxicity, despite their high
anticancer effect.
BACKGROUND
[0007] Among biopharmaceuticals, therapeutic agents using antibody
are being most actively studied, which bind specifically to targets
(i.e., antigens) that are expressed specifically in certain
diseases. Particularly, identification of tumor-related antigens
that are expressed on the surface of cancer cells is being actively
performed, and methods of diagnosing and treating tumors using
antibodies (i.e., anticancer antibodies) that bind to the antigens
to inhibit cell growth or induce cell death are being widely used,
and the field of these methods also has a very good prospect.
[0008] Such anticancer antibodies have very high target
specificity, but their cytotoxic effects on the cancer cells are
usually lower than those of existing cytotoxic drugs (i.e.,
anticancer drugs or agents). So in many cases, these anticancer
antibodies are subject to a combination therapy with cytotoxic
drugs or other cell proliferation inhibitory drugs.
[0009] In connection with the combination therapy as described
above, there have been active studies on a modified antibody-drug
conjugate (mADC), in which the therapeutic effect of the
bound-cytotoxic drugs increases while the toxicity decreases. It is
recognized that when the modified antibody-drug conjugate is used,
the systemic toxicity of the drug can be reduced and the
cytotoxicity of the drug can be enhanced specifically in cells
(particularly cancer cells) having a target overexpressed therein,
thereby increasing the therapeutic effect of the drug.
[0010] Indeed, modified antibody-drug conjugates comprising a
cytotoxic drug or radioisotope conjugated to an antibody, such as
ZEVALIN.TM. [Witzig et al., J. Clin. Oncol, 2002, 20(15):
3262-3269]) or MYLOTARG.TM. [Drugs of the Future, 2000,
25(7):686]), have been successfully developed for the treatment of
non-Hodgkin lymphoma or acute myeloid leukemia. In addition, many
attempts have been made to conjugate highly toxic mertansine (such
as cantuzumab mertansine (Immunogen, Inc. [Xie et al., J. of Pharm.
and Exp. Ther. 2004, 308 (3):1073-1082]) or trastuzumab mertansine
(Roche [Isakoff et al., J. Clin. Oncol. 2011, 29(4): 351-4])) to an
antibody or conjugate other cytotoxic drugs, for example,
dolastatin derivatives such as auristatin peptides, auristatin E
(AE), monomethyl auristatin (MMAE) or MMAF to antibodies like cBR96
(specific to Lewis Y on carcinomas), cAC1O which is specific to
CD30 on hematological malignancies, or anti-CD20 antibody for
treatment of CD20-expressing cancer, or Rituxan for immune
disorders, anti-EphB2R antibody for treatment of colorectal cancer,
2H9, anti-IL-8, or E-selectin antibody ([Klussman, et al.,
Bioconjugate Chemistry, 2004, 15(4):765-773]; [Doronina et al.,
Nature Biotechnology, 2003, 21(7):778-784]; [Francisco et al.,
Blood, 2003, 102(4):1458-1465]) US 2004/0018194 A1) WO 04/032828
A3; [Mao et al., Cancer Research, 2004, 64(3):781-788]; [Bhaskar et
al., Cancer Res, 2003, 63:6387-6394]).
[0011] In addition, an attempt has also been made to develop
modified antibody-drug conjugates using daunomycin, doxorubicin,
methotrexate or vindesine. It is known that bacterial toxins such
as diphtheria toxin, plant toxins such as ricin, or small molecules
such as geldanamycin ([Mandler et al., J. of the Nat. Cancer Inst,
2000, 92 (19):1573-1581]; [Mandler et al., Bioorganic & Med.
Chem. Letters, 2000, 10: 1025-1028]; [Mandler et al., Bioconjugate
Chem, 2002, 13:786-791]), maytansinoid ([EP 1391213 A1]; [Liu et
al., Proc. Natl. Acad. Sci. USA, 1996, 93: 8618-8623]) or
calicheamicin ([Lode et al., Cancer Res, 1998, 58: 2928]; [Hinman
et al., Cancer Res, 1993, 53: 3336-3342]) may be used as drugs in
antibody-drug conjugates. These cytotoxic drugs exhibit cytotoxic
and cell proliferation inhibitory effects by mechanisms such as
tubulin binding, DNA binding or topoisomerase inhibition.
[0012] When a conventional process that was used to induce covalent
linkage between a drug and an antibody is employed to prepare the
antibody-drug conjugate as described above, the drug will be bound
to a number of sites in the antibody, producing a heterogeneous
mixture. For example, a cytotoxic drug is likely to be bound to an
antibody through a number of lysine residues contained in the
antibody to produce a heterogeneous antibody-drug conjugate
mixture. Also, the heterogeneous mixture might have different drug
binding distribution ranging from 0 to about 8 depending on
reaction conditions, which means that the number of drug molecules
bound per unit antibody varies.
[0013] Also for the antibody drug conjugate having the defined
number of drug binding, there might be another potential
heterogeneity, depending on the various conjugation sites.
Homogeneous purification from this heterogeneous mixture is not
suitable for use in the mass production of medicines ([Hamblett et
al., Clin. Cancer Res, 2003, 10, 7063-7070], [Wang et al., Protein
Sci. 2005, 14, 2436-2446]).
[0014] Another method for conjugating a drug to an antibody is
reducing disulfide bonds between cysteine residues in antibody by
reducing agents, and then conjugating drugs to free thiol groups of
the reduced cysteine residues. This method also has disadvantages
in that the inherent characteristics of the antibody can be lost
and a heterogeneous mixture is produced in large amounts.
Specifically, immunoglobulin M is an example of a disulfide-linked
pentamer, while immunoglobulin G is an example of a protein with
internal disulfide bridges bonding the subunits together. In such
proteins, reduction of the disulfide bonds with a reagent such as
dithiothreitol (DTT) or selenol generates reactive free thiols
([Singh et al., Anal. Biochem. 2002, 304:147-156]). This approach
may result in loss of antibody tertiary structure and antigen
binding specificity ([Jagath et al., Nature Biotechnology, 2008,
26(8):925-32]).
[0015] The representative disadvantage of the conventional
antibody-drug conjugation method as described above is that it is
difficult to precisely control the drug conjugation sites in
antibody and the number of conjugated drugs. In an attempt to
overcome this problem and to introduce a free thiol group, a
specific amino acid was substituted with cysteine where the
substituted cysteine did not impair the function of an antibody.
For this purpose, a screening method for optimum cysteine mutant
was developed after predicting the reactivity of thiol group in
each possible mutating site in antibody (Korean Patent Laid-Open
Publication No. 2007-0054682, `ThioFab technology`). An
antibody-drug conjugate of trastuzumab mertansine produced by this
method is in clinical trials for treatment of metastatic breast
cancer ([Burris III et al., J. Clin. Oncol, 2011, 29(4):398-405]).
The above-described ThioFab technology has an advantage in that
damage to a disulfide bond in a parent antibody can be minimized by
introducing a new cysteine into the antibody, but the concern about
modification of the structure and the function of the parent
antibody still remains, because some amino acids in the parent
antibody are mutated by cysteine.
[0016] Accordingly, there is an urgent need for the development of
a novel antibody-drug conjugate and a production method thereof, in
which the number and position of drug molecules conjugated to a
parent antibody can be accurately controlled while retaining the
structural and functional characteristics of the parent
antibody.
DISCLOSURE OF INVENTION
[0017] The present invention has been made in order to solve the
above-described problems occurring in the prior art, and it is an
object of the present invention to provide a novel antibody
(hereinafter referred to as "modified antibody"), which comprises a
motif containing one or more cysteine residues bound to a parent
antibody to provide a plurality of drug-binding sites. Another
object of the present invention is to provide a modified
antibody-drug conjugate comprising a drug bound to the modified
antibody.
[0018] The modified antibody according to the present invention can
efficiently be conjugated with various drugs while retaining the
characteristics of a parent antibody, and thus it can have a high
target specificity and increase the therapeutic effect of the
conjugated drugs.
[0019] The modified antibody of the present invention has
advantages in that it comprises a motif containing one or more
cysteine residues, and thus a drug can be conjugated to the
cysteine residues and the conjugated drug can be effectively
delivered to a target tissue. In addition, the number of cysteine
residues that can bind to the drug can be accurately controlled,
and thus the number or amount of drug molecules in the modified
antibody-drug conjugate can be controlled. Accordingly, the
modified antibody-drug conjugate of the present invention can be
used as an excellent drug delivery system that overcomes the
problem of conventional antibody-drug conjugates and can be
efficiently used for the treatment of diseases such as cancer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee.
[0021] FIG. 1 is a vector map of a modified-antibody expression
vector comprising cysteine-containing trastuzumab.
[0022] FIG. 2 shows the westernblot image of HR-Cys after
purification of trastuzumab (two right lanes) and a
cysteine-containing trastuzumab variant (HR-Cys, two left
lanes).
[0023] FIG. 3 shows the results of UV-VIS spectrometry (FIG. 3A)
and SDS-PAGE (FIG. 3B) performed to confirm whether doxorubicin was
conjugated to HR-Cys.
[0024] FIG. 4 shows the results of SDS-PAGE gel electrophoresis
(FIG. 4A) and the analysis of relative fluorescence intensity of
Alexa488 dye bound to each of the heavy and light chains (FIG. 4B)
for a Her-M2(Cys)-Alexa488 that is a conjugate of a Her-M2(Cys)
antibody variant and Alexa Fluor.RTM. 488.
[0025] FIG. 5 shows the results of an anti-proliferation MTS assay
performed to examine the cell growth inhibitory effect of
HR-Cys-DOX in HER2-expressing BT-474 cells in comparison with those
of Herceptin, a 1:2 mixture of Herceptin and doxorubicin, and
doxorubicin.
[0026] FIG. 6 shows the results of an anti-proliferation assay
performed to examine the cell growth inhibitory effect of
HER-M(Cys)-MMAE that is a Herceptin-MMAE antibody-drug conjugate in
HER2-expressing SK-BR3 cells in comparison with that of
Herceptin.
[0027] FIG. 7 shows the results of observing caspase activation at
various treatment concentrations in order to examine the cell death
effect (apoptosis) of HR-Cys2-MMAE in HER2-expressing SK-BR-3 cells
in comparison with that of Herceptin.
[0028] FIG. 8 shows the results of observing caspase activation at
various treatment concentrations in order to examine the apoptosis
effect of MMAE conjugated to a herceptin antibody variant in
HER2-expressing SK-BR3 cells in comparison with that of
Herceptin.
BEST MODE FOR CARRYING OUT THE INVENTION
[0029] Hereinafter, the present invention will be described in
further detail.
[0030] The present invention provides a novel modified antibody,
which comprises a motif containing one or more cysteine residues
bound to a parent antibody to provide a plurality of antibody drug
sites, and a modified antibody-drug conjugate comprising the
modified antibody. Such a modified antibody can be conjugated to
various drugs while retaining the characteristics of the parent
antibody, and thus can be efficiently used as a modified
antibody-drug conjugate.
[0031] As used herein, the term "parent antibody" means a
conventional "antibody" having no cysteine-containing motif. Any
parent antibody having binding affinity and specificity to a
specific antigen may be used in the present invention without
limitation. Examples of parent antibodies that may be used in the
present invention include monoclonal or polyclonal antibodies, such
as antibodies derived from animals such as mice, chimeric
antibodies, humanized antibodies, and human antibodies developed
using transgenic mice or phage-display technology. In addition, it
will be obvious to those skilled in the art that modified
antibodies such as bispecific antibodies, or fragments of the
antibodies, may also be used in the present invention.
[0032] As used herein, the term "fragment of the antibody" refers
to a fragment that at least retains a binding affinity to an
antigen. Examples of the antibody fragment include single-chain
antibodies, diabodies, triabodies, tetrabodies, Fab fragments,
F(ab').sub.2 fragments, Fd, scFv, domain antibodies, minibodies,
single-chain antibodies (scAb), derivatives of antibody constant
regions, and artificial antibodies based on protein scaffolds.
[0033] In addition, examples of parent antibodies that may be used
in the present invention include all types of immunoglobulin
molecules (e.g., IgG, IgE, IgM, IgD, and IgA) and subtypes thereof
(e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2). In addition, the
parent antibody may be one derived from any species.
[0034] The parent antibody in the present invention has binding
affinity and specificity to cancer-specific antigens such as
tumor-associated antigens (TAAs), cell surface receptor proteins,
cell surface proteins and molecules other than receptor,
transmembrane proteins, signaling proteins, cell survival
regulators, cell proliferation regulators, molecules associated
with (for e.g., known or suspected to contribute functionally to)
tissue development or differentiation, lymphokines, cytokines,
molecules involved in cell cycle regulation, molecules involved in
vasculogenesis and molecules associated with (for e.g., known or
suspected to contribute functionally to) angiogenesis.
[0035] Specifically, antigens to which the parent antibody in the
present invention can bind, but are not limited to:
[0036] (1) BMPRIB (bone morphogenetic protein receptor-type IB;
Genbank Accession No. NM_001203);
[0037] (2) E16 (LAT1, SLC7A5; Genbank Accession No. NM_003486);
[0038] (3) STEAP1 (six transmembrane epithelial antigen of
prostate; Genbank Accession No. NM_012449);
[0039] (4) 0772P (CA125, MUC16, Genbank Accession No.
AF361486);
[0040] (5) MPF (MPF, MSLN, SMR, megakaryocyte potentiating factor,
mesothelin; Genbank Accession No. NM_005823);
[0041] (6) Napi3b (NAPI-3B, NPTIIb, SLC34A2, solute carrier family
34 (sodium phosphate), member 2, type II sodium-dependent phosphate
transporter 3b; Genbank Accession No. NM_006424);
[0042] (7) Sema 5b (FLJ10372, KIAA1445, Mm.42015, SEMA5B, SEMAG,
Semaphorin 5b Hlog, sema domain, seven thrombospondin repeats (type
1 and type 1-like), transmembrane domain (TM) and short cytoplasmic
domain, (semaphorin) 5B; Genbank Accession No. AB040878);
[0043] (8) PSCA hlg (2700050C12Rik, C530008O16Rik, RIKEN cDNA
2700050C12, RIKEN cDNA 2700050C12; Genbank Accession No.
AY358628);
[0044] (9) ETBR (Endothelin type B receptor; Genbank Accession No.
AY275463);
[0045] (10) MSG783 (RNF124, hypothetical protein FLJ20315, Genbank
Accession No. NM_017763);
[0046] (11) STEAP2 (HGNC_8639, IPCA-1, PCANAP1, STAMP1, STEAP2,
STMP, prostate cancer associated gene 1, prostate cancer associated
protein 1, six-transmembrane epithelial antigen of prostate 2,
six-transmembrane prostate protein, Genbank Accession No.
AF455138);
[0047] (12) TrpM4 (BR22450, FLJ20041, TRPM4, TRPM4B, transient
receptor potential cation channel, subfamily M, member 4; Genbank
Accession No. NM_017636);
[0048] (13) CRIPTO (CR, CR1, CRGF, CRIPTO, TDGF1,
teratocarcinoma-derived growth factor; Genbank Accession No.
NP_003203 or NM_003212);
[0049] (14) CD21 (CR2 (Complement receptor 2) or C3DR (C3d/Epstein
Barr virus receptor) or Hs.73792; Genbank Accession No.
M26004);
[0050] (15) CD79b (CD79B, CD7913, IGb (immunoglobulin-associated
beta), B29, Genbank Accession No. NM_000626);
[0051] (16) FcRH2 (IFGP4, IRTA4, SPAP1A (SH2 domain containing
phosphatase anchor protein 1a), SPAP1B, SPAP1C; Genbank Accession
No. NM_030764);
[0052] (17) HER2 (Genbank Accession No. M11730);
[0053] (18) NCA (Genbank Accession No. M18728);
[0054] (19) MDP (Genbank Accession No. BC017023);
[0055] (20) IL20R.alpha. (Genbank Accession No. AF184971);
[0056] (21) Brevican (Genbank Accession No. AF229053);
[0057] (22) EphB2R (Genbank Accession No. NM_004442);
[0058] (23) ASLG659 (Genbank Accession No. AX092328);
[0059] (24) PSCA (Genbank Accession No. AJ297436);
[0060] (25) GEDA (Genbank Accession No. AY260763);
[0061] (26) BAFF-R (B cell-activating factor receptor, BLyS
receptor, BR3, NP_443177.1);
[0062] (27) CD22 (B-cell receptor CD22-B isoform; NP-001762.1);
[0063] (28) CD79a (CD79A, CD79.alpha., immunoglobulin-associated
alpha, a B cell-specific protein that covalently interacts with Ig
beta (CD79B) and forms a complex on the surface with IgM molecules,
transduces a signal involved in B-cell differentiation; Genbank
Accession No. NP_001774.1);
[0064] (29) CXCR5 (Burkitt's lymphoma receptor 1, a G
protein-coupled receptor that is activated by the CXCL 13
chemokine, functions in lymphocyte migration and humoral defense,
plays a role in HIV-2 infection and regarded for development of
AIDS, lymphoma, myeloma, and leukemia; Genbank Accession No.
NP_001707.1);
[0065] (30) HLA-DOB (Beta subunit of MHC class II molecule (1a
antigen) that binds peptides and presents them to CD4+ T
lymphocytes; Genbank Accession No. NP_002111.1);
[0066] (31) P2X5 (Purinergic receptor P2X ligand-gated ion channel
5, an ion channel gated by extracellular ATP, may be involved in
synaptic transmission and neurogenesis, deficiency may contribute
to the pathophysiology of idiopathic detrusor instability; Genbank
Accession No. NP_002552.2);
[0067] (32) CD72 (B-cell differentiation antigen CD72, Lyb-2;
Genbank Accession No. NP_001773.1);
[0068] (33) LY64 (Lymphocyte antigen 64 (RP105), type I membrane
protein of the leucine rich repeat (LRR) family, regulates B-cell
activation and apoptosis, loss of function is associated with
increased disease activity in patients with systemic lupus
erythematosis; Genbank Accession No. NP_005573.1);
[0069] (34) FcRH1 (Fc receptor-like protein 1, a putative receptor
for the immunoglobulin Fc domain that contains C2 type Ig-like and
ITAM domains, may have a role in B-lymphocyte differentiation;
Genbank Accession No. NP 443170.1);
[0070] (35) IRTA2 (Immunoglobulin superfamily receptor
translocation associated 2, a putative immunoreceptor with possible
roles in B cell development and lymphomagenesis; deregulation of
the gene by translocation occurs in some B cell malignancies;
Genbank Accession No. NP_112571.1); and
[0071] (36) TENB2 (putative transmembrane proteoglycan, related to
the EGF/heregulin family of growth factors and follistatin; Genbank
Accession No. AF179274). In addition, examples of the antigens
include all antigens that may be used for treatment and
diagnosis.
[0072] In a preferred embodiment, the parent antibody in the
present invention has binding affinity and specificity to an ErbB
receptor selected from among EGFR, HER2, HER3 and HER4, and other
cancer antigens.
[0073] Particularly, the parent antibody that is used in the
present invention comprises one or more selected from among
trastuzumab (trade name: Herceptin), rituximab (trade name:
Rituxan), bevacizumab (trade name: Avastin), cetuximab (trade name:
Erbitux), cBR96, cAC1O, anti-CD20 antibody, anti-EphB2 antibody,
anti-IL-8, E-selectin antibody, anti-MUC16 antibody, and anti-CD30
antibody, but is not limited thereto.
[0074] HER2 means a member of the epidermal growth factor receptor
(EGFR) family, an important signaling cascade that is implicated in
the proliferation and survival of breast cancer cells. It is known
that the receptor tyrosine kinases of the EGFR family are composed
of erb1, erb2/HER2, erb3 and erb4 and are involved in the
regulation of the adhesion, migration and differentiation of cells
in addition to cell proliferation and proliferation.
[0075] There is no ligand that binds to erb2/HER2 of the four
members of the erb family, but erb2/HER2 is known as the most
potent oncogene in breast cancer. If the level of HER2 is normal,
it is involved in the growth and development of normal mammary
tissue, but if HER2 is abnormally overexpressed or amplified,
normal cell regulation will be broken so that aggressive cancer
cells will be formed in mammary tissue. In other words, if HER2 is
activated by oligomerization with other members of the EGFR family,
it will phosphorylate many downstream molecules, which leads to
activation of a variety of signaling cascades. The
SOS-Ras-Raf-MEK-MAPK pathway that is involved in cell proliferation
and the PI-3K/Akt pathway that inhibits cell death are
representative mechanisms associated with cancer cell
proliferation.
[0076] The results of preclinical and clinical trials indicate that
the overexpression of HER2 is an important biomarker that appears
from the initial state of cancer development and plays an important
role in the growth and progression of cancer. It is known that the
overexpression of HER2 appears in about 20-30% of invasive breast
cancers and is also associated with poor prognosis of breast cancer
with higher aggressiveness and malignancy.
[0077] According to the present invention, a motif containing one
or more cysteine residues is bound to a parent antibody that has
specificity to a growth factor receptor selected from the group
consisting of the HER2 receptors or EGF receptors. And a
conventional anticancer drug is conjugated to the motif to obtain a
modified antibody-drug conjugate of the present invention. When the
modified antibody-drug conjugate is administered to a patient in an
amount effective to inhibit the growth of tumor cells in the
patient, it can exhibit an excellent effect of treating cancer by
inhibiting the growth of tumor cells that overexpress the growth
factor receptor while inducing the dell death.
[0078] In addition, the parent antibody in the present invention is
preferably trastuzumab. Although trastuzumab is prepared so as to
be substantially free of C-terminal lysine (Lys), the modified
antibody-drug conjugate of the present invention could be applied
to trastuzumab that contains lysine (Lys) or trastuzumab that does
not contain lysine (Lys) in the C-terminal region thereof, where
the cysteine (Cys)-containing motif may be bound thereto.
[0079] Amino acids in the present invention are expressed by their
known 3-letter or 1-letter abbreviations. Nucleotides present in
various nucleic acid fragments are designated by the standard
single-letter designation used routinely in the art.
[0080] The cysteine-containing motif in the present invention has
1-100 amino acid residues, preferably 1-50 amino acid residues,
more preferably 1-30 amino acid residues, and most preferably 1-10
amino acid residues, and contains one or more cysteine residues.
Particularly, the cysteine-containing motif in the present
invention preferably contains 1-20 cysteine residues, more
preferably 1-10 cysteine residues, and even more preferably 1-5
cysteine residues.
[0081] The cysteine-containing motif in the present invention may
be a simple peptide motif having no specific functionality or
secondary or tertiary structure and is preferably a motif having a
specific functionality or a secondary or tertiary structure. The
specific functionality is preferably the property capable of
maintaining/protecting the chemical conjugation ability of cysteine
residues, but is not limited thereto. Particularly, the
cysteine-containing motif can more effectively maintain the
functionality of cysteine residues by preventing or retarding the
oxidation of the cysteine residues due to binding to a specific
ligand or the secondary or tertiary structure of the peptide motif
itself.
[0082] The cysteine-containing motif in the present invention has a
structure represented by the following formula 1:
Xa-[(M.sub.Cys).sub.n-Xb.sub.n].sub.n Formula (1)
[0083] wherein (M.sub.Cys).sub.n represents a simple cysteine
residue or a peptide motif that contains a cysteine residue and has
a specific functionality or a secondary or tertiary structure; Xa
and Xb.sub.n each independently represents a peptide comprising 0
to 20 amino acid residues other than cysteine; and n is an integer
ranging from 1 to 20.
[0084] In formula (1), (M.sub.Cys).sub.n, that is,
(M.sub.Cys).sub.1, (M.sub.Cys).sub.2 . . . (M.sub.Cys).sub.n, may
be the same as or different from each other. Also, Xb.sub.n, that
is, Xb.sub.1, Xb.sub.2 . . . Xb.sub.n, may be the same as or
different from each other.
[0085] In addition, if (M.sub.Cys).sub.n in formula (1) is a simple
cysteine residue, the cysteine-containing motif according to the
present invention has a structure represented by the following
formula (2):
Xa-(Cys-Xb.sub.n).sub.n Formula (2)
[0086] wherein Xa, Xb.sub.n and n are the same as defined in
formula 1.
[0087] Also, if (M.sub.Cys).sub.n in formula (1) is a peptide motif
that contains a cysteine residue and has a specific functionality
or a secondary or tertiary structure, (M.sub.Cys).sub.n may
preferably be a metal ion binding motif containing a cysteine
residue. It is known that the metal ion binding motif containing a
cysteine residue can bind to a metal ion to inhibit oxidation of
the cysteine residue, thereby effectively retaining the alkylation
reactivity of the cysteine residue (Van Horn et al. (2003) J. Biol.
Inorg. Chem. 8: 601-610).
[0088] Examples of a metal ion binding motif containing a cysteine
residue, which may be used in the present invention, include, but
are not limited to, metal ion chelators (Zhang et al. (2012)
Biochem. Genet. 50(7-8): 585-599) that are used to control the
concentration of metal ions in vivo, chaperones (Ansbacher and
Shurki, J. Phys. Chem. B (2012) 116(15): 4425-4432; Allen et al.
(2012) Biochemistry 51(7): 1439-48; Click et al. (2012) H. Comput.
Chem. 33(11): 1142-51) that function to deliver metal ions to a
specific position outside or inside cells, transcriptional
regulators (Gunther et al. (2012) Biochim. Biophys. Acta. 1823(2):
476-483; Sitthisak et al. (2012) FEMS Microbiol. Lett. 327(2):
126-133) that regulate transcription depending on the concentration
of metal ions, zinc finger motifs (MacPherson et al. (2006)
Microbiol. Mol. Bio. Rev. 70(3):583-604; Schaeffer et al. (2012)
Nucleic Acids Res. 40(18): 9298-9307) that are widely present in
many proteins and are involved in protein-protein interactions or
protein-DNA interactions, and motifs (Zielazinski et al. (2012)
Biochemistry 51(40):7891-7900; Zhou et al. (2012) FEBS J.
279(2):285-298; Cochran et al. (2011) Nat. Struct. Mol. Biol.
19(1):122-127) derived from various enzymes. The metal ion binding
motifs contains a cysteine residue as an essential binding group
thereof, and such metal ion binding motifs may be used in the
production of the modified antibody-drug conjugate of the present
invention.
[0089] Preferred examples of the metal ion binding motif in the
present invention include, but are not limited to, C.sub.2H.sub.2
group (Cys.sub.2His.sub.2 class:
Cys-X.sub.2-4-Cys-X.sub.12-His-X.sub.3-5-His), C.sub.4 group (C4
class:
Cys-X.sub.2-Cys-X.sub.n-Cys-X.sub.2-Cys-X.sub.m-Cys-X.sub.2-Cys-X.sub.n-C-
ys-X.sub.2-Cys) or C.sub.6 group (C6 class:
Cys-X.sub.2-Cys-X.sub.6-Cys-X.sub.5-12-Cys-X.sub.2-Cys-X.sub.6-8-Cys)
of zinc finger protein, a Cys-X.sub.m-Cys motif such as Cys-X-X-Cys
or Cys-X-Cys, a Met-X-Cys-X-X-Cys motif or a C-Q-C-Q-C-A-C motif,
which is frequently found in transcription regulatory proteins,
metal chaperone proteins, metal ion transporters, superoxide
dismutase or the like, a Ser-Pro-Cys motif of membrane protein
ATPase, etc. In the metal binding peptide motif described above, X
represents amino acid residues other than Cys; m is an integer
ranging from 1 to 10, and preferably from 1 to 5; and X.sub.m or
X.sub.m-q represents amino acid residues other than Cys, the number
of which is indicated by m or m to q.
[0090] More specifically, examples of the metal ion binding motif
of zinc finger protein, which can be used in the present invention,
include, but are not limited to,
TABLE-US-00001 (SEQ ID NO: 1) YKCKQCGKAFGCPSNLRRHGRTH, (SEQ ID NO:
2) YQCNICGGKCFSCNSNLHRHQRTH, (SEQ ID NO: 3)
YSCGICGKSFSDSSAKRRHCILH, (SEQ ID NO: 4) YTCSDCGKAFRDKSCLNRHRRTH,
(SEQ ID NO: 5) YRCKYCDRSFSDSSNLQRHVRNIH, (SEQ ID NO: 6)
YKCKECGKAFNHSSNFNKHHRIH, (SEQ ID NO: 7) FKCPVCGKAFRHSSSLVRHQRTH,
(SEQ ID NO: 8) YRCKYCCDRSFSISSNLQRHVRNIH, (SEQ ID NO: 9)
YECDHCGKAFSIGSNLNVHRRIH, (SEQ ID NO: 10) YGCHLCCKAFSKSSNLRRHEMIH,
(SEQ ID NO: 11) YKCKECGQAFRQRAHLIRFIHKLH, (SEQ ID NO: 12)
YKCHQCGKAFIQSFNLRRHERTH, (SEQ ID NO: 13) FQCNQCGASFTQKGNLNRHIKLH,
(SEQ ID NO: 14) YTCSYCGKSFTQSNTLKQHTRIH, (SEQ ID NO: 15)
YACHLCGKAFTQSSHRRHEKTH, (SEQ ID NO: 16) YKCGQCGKFYSQVSHLTRHQKIH,
(SEQ ID NO: 17) YACHLCGKAFTQCSHLRRHEKTH, (SEQ ID NO: 18)
YACHLCAKAFIQCSHLRRHEKTH, (SEQ ID NO: 19) YVCRECGRGFRQHSHLVRHKRTH,
(SEQ ID NO: 20) YKCEECEGKAFRQSSHLTTHKIIH, (SEQ ID NO: 21)
YECDHCGKSFSQSSHLNVHKRTH, (SEQ ID NO: 22) YMCSECGRGFSQKSNLTIHQRTH,
(SEQ ID NO: 23) YKCEECGKAFTQSSNLTKHKKIH, (SEQ ID NO: 24)
FECKDCGKAFIQKSNLIRHQRTH, (SEQ ID NO: 25) YVCRECRRGFSQKSNLIRHQRTH,
(SEQ ID NO: 26) YECEKCGKAFNQSSNLTRHKKSH, (SEQ ID NO: 27)
YECVQCGKSYSQSSNLFRHQRRH, (SEQ ID NO: 28) YECVQCGKGFTQSSNLITHQRVH,
(SEQ ID NO: 29) YECNTCRKTFSQKSNLIVHQRTH, (SEQ ID NO: 30)
YVCSKCGKAFTQSSNLTVHQKIH, (SEQ ID NO: 31) YKCDECGKNFTQSSNLIVHKRIH,
(SEQ ID NO: 32) YECDVCGKTFTQKSNLGVHQRTH, (SEQ ID NO: 33)
YKCPDCGKSFSQSSSLIRHQRTH, (SEQ ID NO: 34) YECQDCGRAFNQNSSLGRHKRTH,
(SEQ ID NO: 35) YECNECGKFFSQSSSLIRHRRSH, (SEQ ID NO: 36)
YKCEECGKAFNQSSTLTRHKIVH, (SEQ ID NO: 37) YECNECGKAFAQNSTLRVHQRIH,
(SEQ ID NO: 38) YEVHDCGKSFRQSTHTLTQHRRIH, (SEQ ID NO: 39)
YECHDCGKSFRQSTHLTRHRRIH, (SEQ ID NO: 40) HKCLECGKCFSQNTHLTRHQRTH,
(SEQ ID NO: 41) YVCDVEGCTWKFARSDELNRHKKRH, (SEQ ID NO: 42)
YHCDWDGCGWKFARSDELTRHYRKH, (SEQ ID NO :43)
YRCSWEGCEWRFARSDELTRHFRKH, (SEQ ID NO: 44)
FSCSWKGCERRFARSDELSRHRRTH, (SEQ ID NO: 45)
FACSWQDCNKKFARSDELARHYRTH, (SEQ ID NO: 46)
YHCNWDGCGWKFARSDELTRHYRKH, (SEQ ID NO: 47)
FLCQYCAQRFGRKDHLTRHMKHSH, (SEQ ID NO: 48) CRCNECGKSFSRRDHLVRHQRTH,
(SEQ ID NO: 49) FQCKTCQRKFSRSDHLKTHTRTH, (SEQ ID NO: 50)
FACEVCGVRFTRNDKLKIHMRKH, (SEQ ID NO: 51) YVCDVEGCTWKFARSDKLNRHKKRH,
(SEQ ID NO: 52) YKCMECGKAFNRRSHLTRHQRIH, (SEQ ID NO: 53)
YICRKCGRGFSRKSNLIRHQRTH, (SEQ ID NO: 54) YECKECGKAFSSGSNFTRHQRIH,
(SEQ ID NO: 55) FHCGYCEKSFSVKDYLTKHIRTH, (SEQ ID NO: 56)
YECDHCGKAFSVSSNLNVHRRIH, (SEQ ID NO: 57) YTCKQCGKAFSVSSSLRRHETTH,
(SEQ ID NO: 58) YECNYCGKTFSVSSTLIRHQRIH, (SEQ ID NO: 59)
YRCEECGKAFRWPSNLTRHKRIH. (SEQ ID NO: 60) FACDICGRKFARSDERKRHTKIH,
(SEQ ID NO: 61) CPVESCDRRFSRSDELTRHIRIH, (SEQ ID NO: 62)
CDICGRKFARSDERKRHTKIH,
etc. The metal ion binding motif of zinc finger protein may be any
one selected from the metal ion binding motifs of zinc finger
proteins described in http://www.zincfingers.org,
http://www.genenames.org/genefamilies/ZF,
http://www.scripps.edu/mb/barbas/zfdesign/zfdesignhome.php,
https://zifdb.msi.umn.edu:8444/ZiFDB/, or Macpherson et al. (2006)
Microbiol. Mol. Biol. Rev. 70(3), 583-604, which is consistent with
the technical characteristics of the present invention.
[0091] Examples of the metal ion binding motif of transcription
regulatory proteins, metal chaperone proteins or the like, which
can be used in the present invention, include, but are not limited
to, the followings:
TABLE-US-00002 CadC protein: (SEQ ID NO: 63)
CEIFCYDEEKVNRIQGDLQTVDISGVSQILKAIADENRAKITYALCQDEE LCVC, AztR
protein: (SEQ ID NO: 64)
DTHLVHLDNVRSSQAQILPTDKAQQMAEIFGVLADTNRIRLLSALASSEL CVC, ZiaR
protein: (SEQ ID NO: 65)
CDQPLVHLEQVRQVQPEVMSLDQAQQMAEFFSALADPSRLRLMSALARQE LCVC, BxmR
protein: (SEQ ID NO: 66)
CDRAHLVDCSRVGDIQTQVLNTAKAQRMAEFFSLLGDANRLRVVSVLAKQ ELCVC, ArsR
protein: (SEQ ID NO: 67) LSDETRLGIVLLLREMGELCVCDLCM, (SEQ ID NO:
68) CCTLATGPLSSDESEHYADLFKVLGDPVRLRILSQLAAGGC, (SEQ ID NO: 69)
YRAAMPVVRALVAYLTENCCHGTRDC, CmtR protein: (SEQ ID NO: 70)
CLRGCGLVVATYEGRQVRYALADSHLARALGELVQVVLAVDTDQPC, (SEQ ID NO: 71)
LRDCGLVVTVPDGRRSRYELADERLGHALDDLRAAVVAVDADRTCPDADE LECC,
[0092] Zinc (Zn) binding proteins found in membrane proteins that
are involved in bacterial signaling transduction have an inherent
metal ion binding motif composed of one cysteine residue and three
histidine residues (Draper et al., J. Bacteriol. 2011, 193 (17),
4338-4345). Herein, the metal ion binding motif has a structure of
HXXWFYLX.sub.21-28CXLFMVIGXWFLVIX.sub.18-27HXXH, wherein X
represents any amino acid, and X.sub.m-q represents amino acid
residues other than Cys, the number of which is indicated by m to
q. In addition, 150 or more zinc binding proteins reported to date
may be used as the metal ion binding motif in the present
invention.
Known metal ion transporters include cation diffusion facilitators,
Zrt, Irk-like proteins, cation exchangers, copper transporters,
heavy metal P-type ATPase, ATP-binding cassette transporters, etc.
(Hanikenne et al. Plant Physiology 2005, 137, 428-446; Hall and
Williams, J. Experimental Botany, 2003, 54(393) 2601-2613), and the
following M-X-C-X-X-C motif may preferably be used in the present
invention, but is not limited thereto:
TABLE-US-00003 E. coli ZntA: (SEQ ID NO: 72)
VSGMDCAACARKVENAVRQLAGVNQVQVLFA Tn501 MerP: (SEQ ID NO: 73)
VPGMTCSACPITVKKAISEVEGVSKVDVTFE Tn501 MerA: (SEQ ID NO: 74)
ITGMTCDSCAAHVKEALEKVPGVQSALVSY S. aureus CadA: (SEQ ID NO: 75)
VQGFTCANCAGKFEKNVKKIPGVQDAKVNFG Human Menkes: (SEQ ID NO: 76)
VEGMTCNSCVWTIEQQIGKVNGEHHIKVSLE Yeast Atx1: (SEQ ID NO: 77)
VVMTCSGCSGAVNKVLTKLEPDVSKIDIS Rat Wilsons: (SEQ ID NO: 78)
GMTCASCVANIERNLRREEGIYSV Hum Wilsons: (SEQ ID NO: 79)
YEGMTCQSCVSSIEGKYRKLQGVVRYKVSL Rice Cu ATPase: (SEQ ID NO: 80)
GMSCQGCAGAVRRVLTKMEGVETFDIDME H. pylori Cu ATPase: (SEQ ID NO: 81)
VPSITCSHCVDKIEKFVGEIEGVSFIDANVE Ran1: (SEQ ID NO: 82)
VTGMTCAACSNSVEAALMNVNGVDVGGMTCGGCSASVKKLLESQPCVASA SV Cpx89: (SEQ
ID NO: 83) VSGMVCAACSTAVENALLSCSGV Paa1: (SEQ ID NO: 84)
DVGGMTCGGCSASVKKILESQP Cpxl184: (SEQ ID NO: 85)
DVGGMKCGGCVEHVKKILEEQFGVTSAS
[0093] In addition, various metal ion binding motifs artificially
designed based on wild-type metal ion binding motifs found in vivo
may be used in the modified antibody-drug conjugate according to
the present invention. Examples for these metal binding motifs
include, but are not limited to, a CGH motif (Van Horn et al.
(2003) J. Biol. Inorg. Chem. 8: 601-610) designed based on a GGH
motif from Zinc finger protein which does not contain cysteine
residue and metal ion binding motifs (Jancso et al. (2011)
Metallomics 3(12):1331-1339) obtained by substituting one or more
cysteine residues in a peptide motif with other amino acid residue
such as threonine, serine or histidine. The CGH motif has a
structure represented by the following chemical formula 1, and
preferably has a structure of ACGHA having alanines both at the C-
and the N-termini.
##STR00001## [0094] [wherein M represents a metal ion, and R
represent an amino acid residue other than cysteine, preferably
alanine.]
[0095] The CGH motif in the present invention still has the metal
ion binding property even when the positions of the N-terminus and
the C-terminus are reversed. Thus, it will be obvious to those
skilled in this field of art that an HGC motif having the reversed
positions of the N-terminus and the C-terminus falls within the
scope of the CGH motif in the present invention.
[0096] Metal ion binding motifs artificially designed based on zinc
finger motifs, which may be used in the present invention, include
the following metal binding peptide motifs (see Roehm and Berg, J.
Am. Chem. Soc. 1998, 120. 13083-13087) obtained by substituting a
cysteine residue (which plays the most essential role) in
PYKCPECGKSFSQKSALVKHQRTHTH with methyl-cysteine (Me-Cys) or
substituting a histidine residue in this sequence with
cysteine:
TABLE-US-00004 (SEQ ID NO: 86) PYKCPECGKSFSQKSALVKHQRTHTC, (SEQ ID
NO: 87) PYKCPECGKSFSQKSALVKHQRTHTM, (SEQ ID NO: 88)
PYKCPECGKSFSQKSALVKHQRTHT(Me-C), (SEQ ID NO: 89)
PYK(Me-C)PECGKSFSQKSALVKHQRTHTH, (SEQ ID NO: 90)
PYKCPE(Me-C)GKSFSQKSALVKHQRTHTH, and (SEQ ID NO: 91)
PYKCPE(Me-C)GKSFSQKSALVKHQR
[0097] [In the metal binding peptide motif described above, Me-C
represents a methylated cysteine residue.]
[0098] In addition, peptides artificially designed based on many
metal ion binding protein motifs reported to date may also be used
in the present invention.
[0099] Metal ion binding motifs based on the secondary or tertiary
structure of protein include beta-sheets, mixed alpha/beta motifs,
and alpha-helix structures which are most frequently found. The
alpha-helix structures include peptides having single-stranded,
double-stranded, triple stranded or quadruple-stranded alpha-helix
structures.
[0100] With respect to these multiple-stranded alpha-helices, the
TRI family, for example, has a structure of G(LKALEEK).sub.4G
having four repeats of the peptide sequence LKALEEK. Artificially
designed metal ion-binding peptide motifs obtained by substituting
a specific amino acid in this TRI family with cysteine have been
reported (Peakcock et al. 2009. Dalton Trans. 7(13). 2271-2280),
and artificially designed peptide motifs having the following
structures may be used in the present invention, but are not
limited thereto:
TABLE-US-00005 (SEQ ID NO: 92) GLKALEEKCKALEEKLKALEEKLKALEEKG (SEQ
ID NO: 93) GLKALEEKLKALEEKLKACEEKLKALEEKG (SEQ ID NO: 94)
GLKALEEKCKALEEKLKACEEKLKALEEKG (SEQ ID NO: 95)
GLKALEEKLKALEEKCKALEEKLKALEEKG (SEQ ID NO: 96)
GLKALEEKLKALEEKLKALEEKCKALEEKG (SEQ ID NO: 97)
GLKALEEKLKALEEKLKALEEKLKAAEEKCKALEEKG (SEQ ID NO: 98)
GLKALEEKLKALEEKCKALEEKLKAAEEKCKALEEKG (SEQ ID NO: 99)
ELYALEKELGALEKELACLEKELGALEKELYALEK (SEQ ID NO: 100)
KLYALKEKLGALKEKLACLKEKLGALKEKLYALKE (SEQ ID NO: 101)
ELYALEKELGALEKELACLKEKLGALKEKLYALKE (SEQ ID NO: 102)
KLYALKEKLGALKEKLACLEKELGALEKELYALEK
[0101] In addition, many metal ion binding peptide motifs
(Nivorozhkin et al. 2000. Inorg. Chem. 39(11) 2306-2313) having a
circular structure, such as Cyclo[K 1,12] (QCGVCGKCIACK), may also
be used in the present invention.
[0102] Cysteine-containing metal ion binding motifs that may be
used in the modified antibody of the present invention are
summarized in Table 1 below.
TABLE-US-00006 TABLE 1 Cysteine-containing metal ion binding motif
structures that may be used in the present invention Motif
structures Natural protein- Zinc finger C.sub.2H.sub.2 group
Cys-X.sub.2-4-Cys-X.sub.12-His-X.sub.3-5-His derived metal C.sub.4
group
Cys-X.sub.2-Cys-X.sub.n-Cys-X.sub.2-Cys-X.sub.n-Cys-X.sub.2-Cys-X.sub.n-C-
ys-X.sub.2-Cys ion motif C.sub.6 group
Cys-X.sub.2-Cys-X.sub.6-Cys-X.sub.5-12-Cys-X.sub.2-Cys-
X.sub.6-8-Cys transcription regulatory Cys-X.sub.n-Cys proteins,
metal chaperone proteins membrane proteins HXMVFYLX.sub.21-28
CXLFMVIGXWFLVIX.sub.18-27HXXH (x is any amino acid) metal ion
transporters M-X-C-X-X-C Artificially zinc finger motif
PYKCPECGKSFSQKSALVKHQRTHTH synthesized modified peptide metal ion
motif ACGHA multiple-stranded- TRI family Modified peptide of
(LKALEEK).sub.n(n = 1 to helices 5) Others Cyclo(K
1,12)-QCGVCGKCIACK ELYALEKELGALEKELACLEKELGALE KELYALEK
[0103] Such cysteine-containing motifs may be bound to the
N-terminus or C-terminus of the light or heavy chain of a parent
antibody without limitation, so long as a target drug can be
conjugated thereto while maintaining the specificity of the parent
antibody. The motif is preferably bound to the C-terminus of the
heavy or light chain. Particularly, it is bound to the C-terminus
of the heavy chain, that is, the terminus of the constant region of
the parent antibody. If an antibody fragment is used, the motif is
preferably bound to the C-terminus of the heavy chain of the
fragment.
[0104] However, as long as the specificity of the parent antibody
is maintained, the cysteine-containing motif in the present
invention, specifically cysteine motif having a metal ion-binding
functionality or certain specific functionality or a secondary or
tertiary structure, could be linked to any position other than the
heavy and light chain of the parent antibody and may be introduced
into the parent antibody by a long-chain peptide linker. It is well
known that, when an antibody-drug conjugate is produced by
conjugating drugs to site-specifically mutated cysteine or lysine
residues in either heavy or light chains (except CDR region) of
antibody through a long-chain hydrocarbon linker, it still can
retain the structural characteristics and specificity of the parent
antibody. Thus, a cysteine-containing metal ion binding peptide
motif linked to this position of the parent antibody by a
long-chain peptide linker can provide an antibody-drug conjugate
that has high homogeneity while retaining the specificity of the
parent antibody.
[0105] In the modified antibody according to the present invention,
the cysteine-containing motif can be fused directly to the parent
antibody by an amide bond. Alternatively, the terminal functional
group of the cysteine-containing motif can be chemically bound to
the terminal functional group of the parent antibody.
Alternatively, the motif can also be bound to the parent antibody
in a linker mediated manner by using a first linker.
[0106] A drug can be conjugated directly to the cysteine residue
and the thiol group (--SH) of the cysteine in the
cysteine-containing motif bound to the parent antibody and may also
be linked to the cysteine residue through a second linker.
[0107] Binding of the second linker that links a drug to the
cysteine residue in the cysteine-containing motif may be performed
by using alkylation, disulfide exchange or
trans-thioesterification. The second linker may be one or more
selected from among alkyl halide derivatives containing a
haloacetyl functional group, derivatives containing a maleimide
group, aziridine derivatives, acryloyl derivatives, and aryl halide
derivatives containing fluorobenzen or the like, but is not limited
thereto. The derivatives may be bound to the thiol group of the
cysteine residue in the motif by an alkylating reactive group, an
arylating reactive group, a maleimide group, an aziridine group, an
acryloyl group, or a disulfide exchange reactive group containing
pyridyl disulfide and thionitrobenzoic acid (Bioconjugate
techniques, 2nd edition, pp 182.about.192, Gerg T. Hermanson,
ELSVIER).
[0108] For example, a maleimide group that is generally used for
linking thiol and a linker is used to conjugate a drug to cysteine,
because the nucleophilic reactivity of the thiol group of a
cysteine residue for the maleimide group is about 1000 times higher
than that of the amine group or N-terminal amine group of other
amino acid residue, such as lysine residues. Thus in the case of a
modified antibody-drug conjugate comprising maleimide or
iodoacetamide as the second linker, cysteine is bound to the drug
by a thioether bond. Generally, the second linker has a reactive
site having an electrophilic group that reacts with nucleophilic
cysteine present on the antibody.
[0109] A drug that is bound to the modified antibody of the present
invention may be any drug having disease therapeutic effects.
Particularly, it is preferably a cancer therapeutic drug having the
effect of inhibiting the proliferation of tumor cells.
[0110] Specifically, a drug that may be used in the modified
antibody-drug conjugate of the present invention comprises any
compound, moiety or group that has the effect of cytotoxicity or
inhibiting cell proliferation, and examples thereof include:
[0111] (i) chemotherapeutic agents capable of functioning as
microtubulin inhibitors, mitotic inhibitors, topoisomerase
inhibitors, or DNA intercalators;
[0112] (ii) protein toxins capable of functioning as enzymes;
[0113] (iii) micro-RNA (miRNA), siRNA, or shRNA, which can inhibit
the expression of a specific oncogene; and
[0114] (iv) radioisotopes.
[0115] Examples of such drugs include, but are not limited to,
maytansinoid, auristatin, dolastatin, trichothecene, CC1065
(cytotoxic compound), calicheamicin and other enediyne antibiotics,
taxane, anthracycline, methotrexate, adriamycin, vindesine, vinca
alkaloids (vincristine, vinblastine, etoposide), doxorubicin,
melphalan, mitomycin C, chlorambucil, daunorubicin, daunomycin, and
stereoisomers, isosteres, analogs or derivatives thereof, other
intercalating agents, enzymes and fragments thereof such as
nucleolytic enzymes, antibiotics, and toxins such as small molecule
toxins or enzymatically active toxins of bacterial, fungal, plant
or animal origin, and various antitumor or anticancer agents such
as cisplatin, CPT-11, doxorubicin, paclitaxel and docetaxel.
[0116] In addition, a nucleophilic group on the drug moiety in the
present invention includes one or more selected from amine, thiol,
hydroxyl, hydrazide, oxime, hydrazine, thiosemicarbazone, hydrazine
carboxylate and aryl hydrazide groups, which can react with the
second linker moiety and an electrophilic group on the second
linker reagent to form a covalent bond, but is not limited
thereto.
[0117] As described above, the number of drug molecules that can be
conjugated to the antibody by the second linker moiety can increase
as the number of cysteine residues in the motif bound to the parent
antibody increases.
[0118] As described above, the modified antibody according to the
present invention can comprise a number of cysteine residues,
because the motif containing one or more cysteine residues is bound
to the parent antibody, preferably the C-terminus of the parent
antibody. Thus, a large amount of a drug can be conjugated to the
modified antibody in the present invention, and a large amount of
the conjugated drug can be effectively delivered to a target cell
or tissue.
[0119] Also, because the number of cysteine residues that are bound
to the parent antibody is easily controlled, the amount of a drug
that is contained in the modified antibody-drug conjugate (mADC)
can be easily controlled to a desired level. This characteristic
feature overcomes the shortcomings of conventional modified
antibody-drug conjugates, and the novel modified antibody-drug
conjugate according to the present invention can be used as an
excellent drug delivery system and can be used efficiently for the
treatment of diseases such as cancer.
[0120] The present invention also provides a method for producing a
modified antibody, which comprises a motif containing one or more
cysteine residues bound to a parent antibody.
[0121] The parent antibody can be produced by constructing a
suitable expression vector containing a nucleotide sequence
encoding the heavy-chain or light-chain constant domain of the
parent antibody, transforming a prokaryotic or eukaryotic cell with
the constructed expression vector to express an antibody protein,
isolating the antibody protein, and then purifying the isolated
antibody protein to a pharmaceutically acceptable purity.
[0122] A suitable expression vector in the present invention may
include expression regulatory elements, such as a promoter, an
initiation codon, a stop codon, a polyadenylation signal, and an
enhancer, as well as signal sequences for membrane targeting or
secretion. Examples of promoters that are generally available in
prokaryotic cells include lac, tac, T3 and T7 promoters. Examples
of promoters available in eukaryotic cells include simian virus 40
(SV40) promoter, mouse mammary tumor virus (MMTV) promoter, human
immunodeficiency virus (HIV) promoter such as the HIV Long Terminal
Repeat (LTR) promoter, moloney virus promoter, cytomegalovirus
(CMV) promoter, epstein barr virus (EBV) promoter, rous sarcoma
virus (RSV) promoter, as well as .beta.-actin promoter, promoters
from human genes such as human, human hemoglobin, human muscle
creatine and human metallothionein.
[0123] An expression vector may include a selectable marker that
allows selection of host cells containing the vector. Markers that
confer selectable phenotypes, such as resistance to drugs, nutrient
requirement, resistance to cytotoxic agents or expression of
surface proteins, are used as selectable markers. Since only cells
expressing a selectable marker survive in the environment treated
with a selective agent, transformed cells can be selected. Also, a
replicable expression vector may include a replication origin with
a specific nucleic acid sequence which initiates replication.
[0124] As recombinant expression vectors for expressing exogeneous
genes, various types of vectors such as plasmid, virus or cosmid
vectors may be used. The type of recombinant vector is not
specifically limited, as long as it functions to express a desired
gene in various host cells such as prokaryotic and eukaryotic cells
and to produce a desired protein. However, it is preferable to use
a vector that includes a promoter exhibiting strong activity and
can produce exogeneous protein, which retains similarity to a
naturally occurring protein, with high yield.
[0125] A variety of expression host/vector combinations may be used
to express a parent antibody or a modified antibody comprising a
motif containing one or more cysteine residues. Useful expression
vectors for eukaryotic hosts include, but are not limited to,
vectors comprising expression control sequences from SV40, bovine
papilloma virus, adenovirus, adeno-associated virus,
cytomegalovirus and retrovirus. Useful expression vectors for
bacterial hosts include bacterial plasmids, such as plasmids from
E. coli, including pET, pRSET, pBluescript, pGEX2T, pUC, col E1,
pCR1, pBR322, pMB9 and their derivatives, wider host range
plasmids, such as RP4, phage DNAs, e.g., the numerous derivatives
of phage lambda, e.g. .lamda.gt10, .lamda.gt11, NM989, and other
DNA phages, such as M13 and filamentous single stranded DNA phages.
Useful expression vectors for yeast cells include the 2 .mu.m
plasmid and derivatives thereof. Useful vectors for insect cells
include pVL 941.
[0126] In another aspect, the present invention provides a host
cell transformed with the above-described recombinant vector. The
recombinant vector is inserted into a host cell to form a
transformant. A suitable host cell to be transformed with the
vector may be a prokaryotic cell such as E. coli, Bacillus
subtilis, Streptomyces sp., Pseudomonas sp., Proteus mirabilis or
Staphylococcus sp. Also, the host cells may be fungal cells such as
Aspergillus sp., yeast cells such as Pichia pastoris, Saccharomyces
cerevisiae, Schizosaccharomyces sp. and Neurospora crassa, lower
eukaryotic cells, and higher eukaryotic cells such as insect cells.
Also, the host cells may be derived from plants and/or mammals.
Preferred examples of the host cells include, but are not limited
to, PER.C6 cells, monkey kidney cells 7 (COS7; particularly simian
COS cells), NSO cells, SP2/0, Chinese hamster ovary (CHO) cells,
W138, baby hamster kidney (BHK) cells, Madin-Darby canine kidney
(MDCK) cells, myeloma cell lines, HuT 78 cells, HEK293 cells, and
other mammalian host cells that produces the antibody protein
according to the present invention.
[0127] Particularly, to maximize expression efficiency, the host
cell in the present invention is preferably one or more selected
from among E. coli cells, simian COS cells, Chinese hamster ovary
(CHO) cells, and other mammalian host cells that produces the
antibody protein according to the present invention. More
preferably, the host cell in the present invention is the hamster
ovary cell CHO-K1.
[0128] In the present invention, "transformation" into host cells
include any method for introducing nucleic acids into organisms,
cells, tissues, or organs and may be performed using a standard
technique selected depending on the type of host cell as known in
the art. Examples of this method include, but are not limited to,
electroporation, protoplast fusion, calcium phosphate (CaPO.sub.4)
precipitation, calcium chloride (CaCl.sub.2) precipitation,
agitation using silicon carbide fiber, agrobacterium-mediated
transformation, and PEG-, dextran sulfate-, lipofectamine- or
desiccation/inhibition-mediated transformation.
[0129] The antibody protein expressed as described above can be
recovered from the host cell, the supernatant of the culture, or
the cells after lysis, and purified by using a conventional protein
purification technique, to yield the modified antibody comprising a
motif containing one or more cysteine residues.
[0130] The antibody can be isolated from the culture medium by a
conventional immunoglobulin purification procedure, for example,
protein A Sepharose, hydroxyl-apatite chromatography, gel
electrophoresis, dialysis, or affinity chromatography.
[0131] Nucleotide sequence encoding the cysteine containing motif
can be fused to a nucleotide sequence encoding either heavy-chain
constant domain or light-chain constant domain of parent
antibody.
[0132] Recombinant vector fused in this way can produce modified
antibody with the similar method employed in parent antibody after
transformed and expressed in prokaryotic or eukaryotic host
cell.
[0133] In addition, the modified antibody of the present invention
can be produced by expressing each of a parent antibody and a motif
containing one or more cysteine residues, and then chemically
linking the terminal functional group of the parent antibody to the
terminal functional group of the cysteine-containing motif or
linking the parent antibody to the motif by a first linker. A drug
may be bound to the produced modified antibody with the
cysteine-containing motif, thereby producing a modified
antibody-drug conjugate (mADC).
[0134] Specifically, a modified antibody-drug conjugate with
multiple cysteines-containing motif can be produced by:
[0135] (a) conjugating a parent antibody containing a
cysteine-containing motif with a linker reagent to form an
covalently bound antibody-second linker intermediate, and then add
an activated drug moety to the intermediate; or
[0136] (b) conjugating the nucleophilic group of a drug moiety with
a second linker reagent to form a covalently bound drug-second
linker intermediate, and then add a modified antibody with a
cysteine-containing motif.
[0137] In another aspect, the present invention provides a
therapeutic composition comprising the modified antibody-drug
conjugate as an active ingredient.
[0138] In the above mentioned composition, the drug conjugated to a
modified antibody-drug conjugate may be a cytotoxic agent, a cell
proliferation inhibitor, a chemotherapeutic agent, an immune
inhibitor, an anti-inflammatory agent or the like, but is not
limited thereto. In cancer therapy, the use of the antibody-drug
conjugate for local delivery of a drug that kills or inhibits tumor
cells allows the targeted delivery of the drug moiety into tumor
cells by antibody-antigen interactions and the intracellular
accumulation of the drug moiety. Administration of non-conjugated
drug formulation may cause an unacceptable level of toxicity not
only in tumor cells, but also in normal cells. However, the
modified antibody-drug conjugate according to the present invention
can accurately deliver the drug due to the high antigen specificity
of the antibody, increasing the therapeutic effect of the drug. In
addition, it can expand the usability of drugs, particularly
anticancer agents, the use of which is limited due to their
toxicity, despite their high anticancer efficacy. According to the
present invention, an antibody-drug conjugate that maximizes drug
efficacy while minimizing drug toxicity is provided.
[0139] The present invention also provides a method of inhibiting
the proliferation of target cells from cancer, autoimmune,
inflammatory or infectious disease by the modified antibody-drug
conjugate as an active ingredient.
[0140] Cancer that can be treated according to the present
invention may be one or more selected from among liver cancer,
stomach cancer, breast cancer, colon cancer, bone cancer,
pancreatic cancer, head and neck cancer, uterine cancer, ovarian
cancer, rectal cancer, esophageal cancer, small intestine cancer,
anal cancer, fallopian tube cancer, endometrial cancer, cervical
cancer, vaginal cancer, valve cancer, Hodgkin's disease, prostate
cancer, bladder cancer, kidney cancer, ureter cancer, renal cell
carcinoma, renal pelvis cancer, and cancer of the central nervous
system. In a specific example, proliferation of HER2-amplified
breast cancer BT-474 cells can be inhibited by bringing the
modified antibody-drug conjugate into contact with the cells in
vitro. Therefore, it is evident that the inventive method of
inhibiting the proliferation of target cells using the modified
antibody-drug conjugate as an active ingredient has the effect of
killing cells related to the above-described disease or reducing
the proliferation rate of the cells.
[0141] Hereinafter, the present invention will be described in
further detail with reference to examples. It will be obvious to a
person having ordinary skill in the art that these examples are not
to be construed to limit the scope of the present invention, and
various modifications and changes can be made within the technical
idea and scope of the present invention.
[0142] Unless otherwise defined, the technical or scientific terms
as used herein have the same meanings as understood by those having
ordinary knowledge in the technical field to which the present
invention pertains. Also, detailed description of the same
construction and effect as those of the prior art will be omitted
herein.
1. ANALYTICAL METHOD
[0143] 1.1: UV-VIS Spectrophotometry
[0144] In the present invention, an antibody-drug conjugate was
produced by using a drug (DOX-EMCH) with a linker attached to the
anticancer agent doxorubicin (6-maleimidocaproyl)hydrazone. The
DOX-EMCH, when injected into a human body, binds to the thiol group
of cysteine present in blood albumin to form an albumin-drug
conjugate [Willner et al., Bioconjugate Chem. 1993 (4):521-7] and
can be easily applied in describing the present invention.
[0145] In order to examine whether a drug is still bound to a
protein after conjugation and purification steps, UV-VIS absorption
spectroscopy is usually employed. Protein shows the maximum
absorbance at a wavelength of 280 nm (UV wavelength range), and
doxorubicin used in the present invention has the maximum
absorbance at 495 nm (visible wavelength range). Both protein and
doxorubicin have characteristic absorption coefficients,
respectively, at specific wavelength region. Therefore when the
absorbance is measured at 280 nm and 495 nm, the equivalent of drug
bound per molecule of protein is determined (U.S. Pat. No.
7,528,234 B2).
[0146] 1.2: In Vitro Cell Proliferation Inhibition Assay
[0147] The cytotoxicity or cell proliferation inhibitory activity
of the modified antibody-drug conjugate (mADC) was determined by
exposing mammalian cells having receptor protein, for example,
SK-BR-3 or BT-474 cells, to the modified antibody-drug conjugate
(mADC) in cell culture medium. The mADC-treated cells were cultured
for about 6 hours.about.5 days, and measured its viability.
[0148] 1.3: Measurement of In Vitro Caspase 3/7 Activity
[0149] Herceptin does not directly induce cancer cell death, but
does induce the death of Her2-positive cancer cells by ADCC
(antibody-dependent cellular cytotoxicity). However, a drug therapy
directly induces apoptotic cell death, therefore when the caspase
activity is measured, it could be determined whether the modified
antibody-drug conjugate (mADC) induces caspase-mediated apoptosis
or not (Bayascas, et al. (2002), Cell Death and Differentiation. 9:
1078-1089; Preaudat, et al (2002), Journal of Biomolecular
Screening. 7: 267-274; Phillips, et al. (2008), Cancer Research
68(22): 9280-9290).
[0150] In the present invention, in order to examine the mechanism
of apoptosis by the modified antibody-drug conjugate (mADC), the
activity of caspase 3/7 was measured. Generally, apoptosis by the
modified antibody-drug conjugate (mADC) is determined by exposing
mammalian cells having receptor protein, for example, SK-BR-3 cells
or BT-474 cells, to the modified antibody-drug conjugate (mADC).
The mADC-treated cells were cultured in medium for .about.2 days,
and was measured its caspase activity.
2. EXAMPLES
Example 1. Preparation of Expression Vector pAV4
[0151] Cloning of the expression vector required in the present
invention was performed by using a pAV4 vector which was
constructed and modified from the parent vector pSGHV0 (GenBank
Accession No. AF285183), so as to be used for antibody production
in the industrial field. Although human protein could be
overexpressed in bacterial cells such as E. coli, it is difficult
to obtain as an active substance. Therefore the parent vector was
manufactured to express physiologically active protein in high
concentration in animal cells in vitro, together with easy
purification steps. Albeit its biggest merit of high protein
expression level from this parent vector, there is a limitation for
its use in the industrial field Therefore the pAV4 vector was
modified from its parent vector to be adaptable in the industrial
field. In addition, the pAV4 vector is modified adequately for the
purpose of expressing both the heavy-chain and light-chain domains
of antibody.
Example 2: Construction of Vectors for the Production of
Trastuzumab and Cysteine Modified Trastuzumab
[0152] To construct a trastuzumab (HHL002) vector, the cDNAs of the
heavy chain and light chain of trastuzumab were synthesized into
codon-optimized sequences so that the expression thereof in CHO
cells is maximized. The genes were respectively cloned into the
XhoI/NotI and Apal/Smal restriction sites of the pAV4 vector,
thereby a trastuzumab vector (pHHL002) was prepared.
[0153] 2.1: Construction of Vectors for the Modified Trastuzumab
Antibodies HR-Cvs and HR-Cvs-Gly-Cs
[0154] In order to construct vectors for modified trastuzumab
antibodies, HR-Cys (HHL002C), a single cysteine mutant in replace
of terminal lysine at the C-terminus and another trastuzumab
variant HR-Cys-Gly-Cys (HHL002C2) with a C-terminal peptide
consisting of Cys-Gly-Cys (CGC), PCR amplification was performed
using the constructed trastuzumab vector (pHHL002) as a template.
Specifically, PCR amplification was performed using trastuzumab as
a template and a XhoHH forward primer (5'-GGG GGG CTC GAG ACC ATG
GGT TGG AGC TGT-3') and an HHNot reverse primer (5'-GCG GCC GGC CGC
TCA ACA ACC CGG AGA CAG-3') for HHL002C or an HHNot reverse primer
(5'-GCG GCC GGC CGC TCA ACA GCC ACA ACC CGG AGA CAG-3') for
HHL002C2. The amplified nucleotide sequence was cleaved with the
restriction enzymes XhoI and NotI and ligated with the expression
vector pHHL002 having XhoI/NotI cleavage sites, thereby
constructing cysteine modified trastuzumab antibody vectors
(pHHL002C; pHHL002C2). FIG. 1 is a schematic view of the vector.
The cysteine-containing variant antibody produced in this Example
is a cysteine-containing trastuzumab antibody containing a deletion
of lysine at the C-terminus and an addition of single cysteine or a
short peptide of cysteine, glycine and cysteine.
[0155] 2.2: Construction of a Vector for the Modified Trastuzumab
Antibody HR-M2(Cys)
[0156] In order to construct a vector encoding a modified
trastuzumab antibody HR-M2(Cys) (HR-ACHGAACGHA; HHL002M2) which has
two metal ion binding motifs (CGH), PCR amplification was performed
by using the trastuzumab vector (pHHL002) as a template and a XhoHH
forward primer (5'-GGG GGG CTC GAG ACC ATG GGT TGG AGC TGT-3') and
an M2 reverse primer (5' CCCCGC GGC CGC CTA GGC ATG GCC ACA AGC AGC
ATG GCC ACA GGC GCC GGG AGA CAG AGA 3'). The amplified nucleotide
sequence was cleaved with the restriction enzymes XhoI and NotI and
ligated with the expression vector pHHL002 having XhoI/NotI
cleavage sites, thereby constructing a cysteine modified
trastuzumab antibody vector (pHHLO02M2).
[0157] 2.3: Production of Modified Trastuzumab Antibody HR-M(Cvs)
In order to construct a vector encoding modified trastuzumab
antibody HR-M(Cys) (HR-GGGACGHA; HHL002M) which has a single metal
ion binding motif (CGH), PCR amplification was performed by using
an EzChange Site-directed mutagenesis kit (Enzynomics, Ez004S). The
above-produced modified trastuzumab antibody HR-M2(Cys) was used as
a template with a forward primer (5'-GGT GGA GGT GCT TGT GGC CAT
TAA GC) and a reverse primer (3'-GCC GGG AGA CAG AGA CAG TG). From
the two metal ion binding motifs in HR-M2(Cys), the one metal ion
binding motif from the C-terminus was removed and a glycine
linker(GGG) was added between the remaining motif and the parent
antibody. After EzChange per amplification, the original template
HR-M2(Cys) was cleaved with the restriction enzyme DpnI, and the
resulting 5-M(Cys) was ligated into a double-stranded DNA vector by
ligase, thereby constructing a modified trastuzumab antibody vector
(pHHL002M).
[0158] 2.4: Construction of a Vector for Modified Trastuzumab
Antibody HR-M2L(Cys)
[0159] In order to construct a vector encoding modified trastuzumab
antibody HR-M2L(Cys) (HR-ACGHAGGGACGHA, HHL002M2L) with an three
amino acid linker (GGG) inserted between metal ion binding motifs
(CGH), PCR amplification was employed. The above-produced modified
vector for trastuzumab antibody HR-M2(Cys) was used as a template
with a forward primer (5'-GGT GGA GGTGCT TGT GGC CAT GCC TAA GCG)
and a reverse primer (3'-AGC ATG GCC ACA GGC GCC). After the
original template HR-M2(Cys) was cleaved with the restriction
enzyme DpnI, the resulting nucleotide encoding 5-M2L(Cys) was
ligated into a double-stranded DNA vector by ligase, thereby
constructing a modified trastuzumab antibody vector
(pHHL002M2L).
[0160] 2.5: Construction of a Vector for Modified Trastuzumab
Antibody HR-Z(Cys)
[0161] In order to construct a vector encoding HR-Z(Cys)
(HR-CDICGRKFARSDERKRHTKIHLRQK, HHL002Z) which has a metal ion
binding motif from Class I zinc finger protein, PCR amplification
was performed using the trastuzumab vector (pHHL002) as a template
with a XhoHH forward primer (5'-GGG GGG CTC GAG ACC ATG GGT TGG AGC
TGT-3', SEQ ID NO: 1) and a Z reverse primer (5'-GCA TGC GGC CGC
CTT ACT TCT GCC GCA GGT GGA TCT TGG TAT GCC TTT TTC GCT CGT CGG ATC
TAG CAA ATT TGC GTC CAC AAA TAT CGC ATT TGC CGG GAG ACA GAG A-3').
The amplified nucleotide sequence was cleaved with the restriction
enzymes XhoI and NotI and ligated with the expression vector
pHHL002 having XhoI/NotI cleavage sites, thereby constructing a
cysteine modified trastuzumab antibody (pHHL002Z).
Example 3: Expression and Purification of Trastuzumab and Cysteine
Modified Trastuzumab Antibody
[0162] By using Chinese hamster ovary cells (CHO-K1), the
expression of trastuzumab (HHL002) and its cysteine-modified
antibodies (HHL002C, HHL002C2, HHL002M, HHL002M2, HHL002M2L,
HHL002Z) were analyzed. Specifically, CHO-K1 cells were cultured in
DMEM (Dulbecco's Modified Eagle Media) containing 10% FBS (fetal
bovine serum) and antibiotic. The CHO-K1 cells were inoculated in a
100 mm culture dish at a concentration of 5.times.10.sup.6 cells/ml
and then cultured for 24 hour. 800 .mu.l of FBS- and
antibiotics-free DMEM was mixed with 10 .mu.g vector and incubated
at room temperature for 1 minutes, after which the mixture was
mixed with 20 .mu.g PEI (Polyethylenimine, linear, Polysciences Inc
(Cat. no: 23966, MW-25,000)) and allowed to stand at room
temperature for about 10-15 minutes. Meanwhile, the cells were
washed with PBS and 6 ml of fresh DMEM was added thereto. The
trastuzumab or cysteine-modified trastuzumab antibody vector
maintained at room temperature for 10-15 minutes was added to the
culture dish. On the next day, the cells were washed with PBS, and
FBS-free IMDM medium (Cat. No 12200-028, Gibco, Iscove's Modified
Dulbecco's Medium) was added thereto to confirm the expression of
the antibody protein.
[0163] The trastuzumab and cysteine modified trastuzumab antibodies
expressed as described above were purified in the following manner.
Specifically, in order to purify the trastuzumab and cysteine
modified trastuzumab antibodies secreted into the cell culture
medium, the culture medium was centrifuged to remove cells, and the
supernatant was injected into HiTrap Protein A HP column (GE
Healthcare, USA) which was equilibrated with equilibration buffer.
The column was sufficiently washed with equilibration buffer and
then the protein was eluted by pH change with glycine buffer (100
mM Glycine, pH 2.8). The resulting solution was dialyzed against
phosphate buffer, and then concentrated by using Vivaspin20
(Sartorius, USA).
Example 4: Production of a Variant Antibody and Drug Conjugate
[0164] 4.1: Production of a Trastuzumab-Based Variant Antibody and
Drug (Doxorubicin) Conjugate
[0165] In general, if the cysteine residues of proteins do not
participate in a intramolecular disulfide bond, the proteins
usually form a dimer by intermolecular disulfide bond. However, as
shown in FIG. 2, HR-Cys produced in the present invention was
present as a whole monomeric antibody as determined by SDS-PAGE and
Western blot analysis. In addition, a cysteine residue having a
free thiol group in the protein can form a disulfide bond with
intracellular glutathione or cysteine. For this reason, in order to
break the disulfide bond, a step of treatment with a reducing
agent, such as DTT (dithiothreitol) or TCEP (tris(2-carboxyethyl)
phosphine), is required upon binding with a drug-second linker, but
a sufficient binding reaction can also be achieved even by
agitation at room temperature.
[0166] The second linker-conjugated drug used in this experiment is
a (6-maleimidocaproyl)hydrazone derivative of doxorubicin known as
DOXO-EMCH. A method of attaching a compound such as DOXO-EMCH,
which has a maleimide group, to the thiol group of protein, is well
described in the literature [Klussman, et al. (2004), Bioconjugate
Chemistry 15(4): 765-773, page 766; Emmanuel et al. (2010)
Chemistry & Biology 2010(17):213-227].
[0167] HR-Cys purified in the present invention was mixed with
DOXO-EMCH at a molar ratio of 1:10 and agitated at room temperature
for 4 hours. Then, the remaining DOXO-EMCH was removed using a
desalting column, and the remaining material was washed three times
by ultrafiltration, thereby producing a HR-Cys-doxorubicin
conjugate (HR-Cys-DOX). The produced conjugate was confirmed by
UV-VIS spectrophotometry as shown in FIG. 3. From calculation based
on the characteristic absorption coefficients of the protein and
the drug, it could be seen that about two molecules of DOXO-EMCH
were bound per HR-Cys molecule.
[0168] 4.2: Production of a Trastuzumab-Based Modified Antibody and
Drug(MMAE) Conjugate
[0169] In the present invention, MMAE known to have cytotoxicity
much higher than doxorubicin was conjugated to HR-Cys-GLy-Cys to
make a Herceptin-MMAE conjugate (HR-Cys2-MMAE). Monomethyl
Auristatin E (see Chemical Formula 2 below), a conjugatable
derivative of Auristatin, is linked to the thiol-specific maleimide
group through a valine-citurulline, which could be degraded by
protease in cells, and a self-degrading spacer, para-aniline
benzoic acid (PABA). This is known as MC (maleimido caproic
acid)-VC(valine-citurulline)-PAB-MMAE, and a synthesis method
thereof is already well known (U.S. Pat. No. 6,214,345; U.S. Pat.
No. 7,745,394). Auristatin, a highly cytotoxic compound, is known
to have an IC50 value of 200-300 pM in a cell proliferation
inhibition assay.
##STR00002##
[0170] In the present invention, 2-10 equivalents of the reducing
agent TCEP was added to the modified trastuzumab antibody and
reacted at 4.degree. C. for 30 minutes to reduce the thiol group,
after which 2-10 equivalents of MC-vc-PAB-MMAE was added thereto
and reacted at room temperature for about 2-4 hours. The reaction
was terminated by addition of an excess amount of cysteine, and
unreacted MC-vc-PAB-MMAE and TCEP were removed by
centrifugation-filtration and dialysis in phosphate buffered
saline, thereby obtaining a purified trastuzumab
variant-MC-vc-PAB-MMAE.
[0171] In order to confirm the selective binding specificity of the
produced trastuzumab variant-MC-vc-PAB-MMAE, the peptide mapping of
the produced HR-M2(Cys)-MC-vc-PAB-MMAE was performed (ProteinWorks
Co., Ltd., Daejeon, Korea). The results of the peptide mapping
indicated that MC-vc-PAB-MMAE was introduced into the peptide
cysteine residue that is a drug binding site in the C-terminus of
heavy chain. Binding of the drug to the cysteine derived from the
intrachain or interchain disulfide bond of the heavy or light chain
was not observed. This suggests that the antibody variant designed
in the present invention was effectively synthesized, which can
significantly increase the homogeneity of the antibody-drug
conjugate with the drug bound specifically to the C-terminus of the
heavy chain.
[0172] 4.3: Analysis of Selective Conjugation Property of Modified
Trastuzumab Antibody by Using a Maleimide-Containing Fluorescent
Dye, Alexa Flour.RTM. 488.
[0173] In order to examine whether a drug is selectively conjugated
to a cysteine residue introduced into the C-terminus of Trastuzumab
heavy chain, fluorescent dye Alexa Fluor.RTM. 488 substituted with
a thiol-specific maleimide group was reacted with each of the
modified trastuzumab antibodies. When the cysteine residues of
proteins do not form an intramolecular disulfide bond, the proteins
usually form a dimer by an intermolecular disulfide bond. However,
as shown in FIG. 2, HR-Cys produced in the present invention was
present as a whole monomeric antibody as determined by SDS-PAGE and
Western blot analysis. In addition, a cysteine residue having a
free thiol group can form a disulfide bond with intracellular
glutathione or cysteine. For this reason, in order to break the
disulfide bond, a step of treatment with a reducing agent, such as
DTT (dithiothreitol) or TCEP (tris(2-carboxyethyl) phosphine), is
required upon binding with a drug-second linker, but a sufficient
binding reaction can also be achieved even by agitation at room
temperature. 2-4 equivalents of the reducing agent can reduce not
only a cysteine residue introduced into the C-terminus of the heavy
chain, but also the intrachain disulfide bond of each of the heavy
and light chains and the interchain disulfide bond that links the
heavy chain to the light chain. Thus, fluorescent dye can be bound
to any cysteine residue reduced by the reducing agent. A drug that
is bound to an interchain or intrachain disulfide can reduce the
homogeneity of the antibody-drug conjugate, and the bound drug
having a relatively large size is highly likely to reduce the
structural stability and antigen specificity of the antibody
protein itself, and for this reason, the efficacy thereof in the
manufacture of biomedicines can be significantly reduced.
[0174] 2-4 equivalents of TCEP is added to the modified trastuzumab
antibody and reacted at 4.degree. C. for about 30 minutes to reduce
the thiol group. In this process, either the antibody variant
present as a dimer with a disulfide bond or the thiol functional
group of cysteine which is present in an oxidant-bound form during
an expression process is restored to a reduced form that can bind
to a maleimide group. After the reduction reaction, the reducing
agent such as DTT, which is reactive to the maleimide group, should
be removed by, for example, centrifugation-filtration, but TCEP,
which is not involved in the conjugation reaction between the
maleimide group and the thiol group, is not necessarily removed.
2-10 equivalents of Alexa Fluor.RTM. 488 is added to the modified
trastuzumab antibody and reacted with stirring at room temperature
for about 2-4 hours. The reaction is terminated by addition of an
excess amount ofcysteine, and unreacted dye and reducing agent are
removed by centrifugation-filtration. The resulting material is
dialyzed against phosphate buffered saline, thereby obtaining a
modified trastuzumab antibody-Alexa488 dye conjugate.
[0175] The modified trastuzumab antibody-Alexa488 dye conjugate
obtained as described above was separated by SDS-PAGE gel
electrophoresis, and then the amount of the dye bound to each of
the heavy and light chains was analyzed by a fluorescence image
analyzer (Fluorescencen Image Ananlyzer, Typoon9410, Amersharm
Bioscience Ltd.). The results of the fluorescence image analysis
indicated that, in the case of the HR-Cys and HR-Cys-Gly-Cys
antibody variants, the amount of the dye bound to the heavy chain
was larger than that of the dye bound to the light chain. Also in
the case of HR-M(Cys), HR-M2(Cys), HR-M2L(Cys) and HR-Z(Cys), the
amount of the dye bound to the heavy chain was larger than the
amount of the dye bound to the light chain. As can be seen in FIG.
4, in the case of the HR-M2(Cys) antibody variant, the intensity of
the fluorescent dye bound to the heavy chain was about 6 times
higher than the intensity of the dye bound to the light chain. This
difference in fluorescence intensity indicates that the amount of
the dye bound to the heavy chain is much larger than the amount of
the dye bound to the light chain, suggesting that the selectivity
of the maleimide group to the heavy chain is significantly
greater.
Example 5: Measurement of Metal Ion Binding Affinity of Metal Ion
Binding Motif
[0176] As mentioned above, metal ions bind to a peptide having the
metal ion binding motif CGH and inhibit or retard the oxidation of
the cysteine residue, thereby preventing a sulfonation reaction
caused by over-oxidation of the cysteine. Oxidation of the cysteine
residue can occur through two reaction pathways. In one reaction
pathway, a disulfide bond can be created by thiol-thiol bonding,
and in the other pathway, cysteine can also be oxidized by reaction
with an excess of oxygen in air to produce sulfenic acid (R--S--OH)
as an intermediate product. In this case, the disulfide formation
is a reversible reaction in which the disulfide bond can be reduced
to thiol, but the formation of sulfenic acid by reaction with
oxygen is an irreversible one. When disulfide and sulfenic acid are
exposed to oxygen for a long period of time, they are all oxidized
to sulfonic acid (R--SO.sub.3H) by an irreversible reaction.
Because this sulfenic acid or sulfonic acid have no reactivity to
maleimide, oxidation to sulfenic or sulfonic acids reduce the
reactivity of the antibody variant with maleimide, and thus can
greatly influence the conjugation yield and homogeneity of the
antibody-drug conjugate.
[0177] As described above, it has been reported that a peptide
containing the synthetic motif CGH, derived from the metal ion
binding motif GGH that is frequently found in vivo, binds metal
ions and inhibits the sulfonation of cysteine (Van Horn et al.
(2003) J. Biol. Inorg. Chem. 8: 601-610). After secreted to
extracellular medium during expression process, antibody protein
having the metal ion binding peptide motif can bind to a trace
amount of metal ions present in the cell culture medium and
effectively inhibits the sulfonation of cysteine. In order to
measure the metal ion binding ability of the antibody variant
having this metal ion binding peptide motif, the binding affinity
was measured by using a Fura-2 (Invitrogen, F-1200), a well-known
metal ion chelator. From this measurement, HR-M2(Cys) had a
dissociation constant (K.sub.d) of about 20 nM, suggesting that it
formed a very strong bond with metal ions. In addition, to examine
whether the antibody variant having a metal ion binding motif binds
to metal ions and protects the cysteine residue, the alkylation
rate was measured. It was observed that the antibody variant formed
a very strong bond with zinc metal ions, and thus inhibited the
cysteine alkylation for up to 24 hours compared to when there was
no metal ion. Nickel ions did not bind to the CGH motif as strongly
as zinc ions did, suggesting that the effect of inhibiting the
cysteine alkylation is lower than that of zinc ions. However, when
compared with the buffer without metal ions, nickel ions reduced
the alkylation rate of cysteine. When a strong metal ion chelator
EDTA was added to remove zinc ions from HR-M2(Cys), it was observed
that the alkylation of cysteine occurred quickly, like the case in
which there was no extraneously added metal ions.
Example 6: In Vitro Assay for Cell Proliferation Inhibition
[0178] 6.1: Cell Proliferation Inhibition Assay of a Variant
Antibody and Doxorubicin Conjugate
[0179] BT-474 cells were diluted with 10% FBS-containing DMEM/F12
medium, and 100 .mu.l of the diluted cell suspension was inoculated
into each well of a 96-well plate at a density of 1.times.10.sup.4
cells/well. After inoculation, the well plate was incubated in a 5%
CO.sub.2 incubator at 37.degree. C. for 24 hours. Each of
Herceptin, a 1:2 mixture of Herceptin and doxorubicin, HR-Cys-DOX
prepared in the above Example, and doxorubicin, was diluted in
medium, and then 100 .mu.l of each dilution was added to each well
of the plate at various concentrations of 1000 nM, 100 nM, 10 nM, 1
nM and 0.1 nM. Also medium (having no drug) was added to another
wells for negative control. After incubation for about 5 days, 20
.mu.l of CellTiter 96-AQueous One Solution reagent [MTS-based
assay; measuring cell proliferation by the amount of purple
formazan formed by MTS due to the dehydrogenase of viable cells]
was added to each well, followed by incubation in an incubator at
37.degree. C. for 2 hours. 20 .mu.l of 10% SDS solution was added
to each well to stop the reaction, followed by sufficient mixing to
induce cell lysis. The absorbance of each well was measured by a
spectrophotometer, and the viability (%) based on the absorbance is
graphically shown in FIG. 5. As a result, it was shown that the
cell growth inhibitory effect of HR-Cys-DOX used in low
concentrations was similar to those of Herceptin and the 1:2
mixtures of Herceptin and doxorubicin and HR-Cys-DOX at a high
concentration showed cytotoxicity similar to that of doxorubicin.
These results indicate that HR-Cys-DOX retains the characteristic
function of Herceptin and sufficiently exhibits the characteristic
cytotoxicity of doxorubicin, even though the doxorubicin is bound
Herceptin by the second linker.
[0180] 6.2: Cell Proliferation Inhibition Assay of a Variant
Antibody and MMAE Conjugate
[0181] SK-BR3 cells were diluted in 10% FBS-containing DMEM/F12
medium, and 100 .mu.l of the cell diluted suspension was added to
each well of a 96-well plate at a density of 1.times.10.sup.4
cells/well. Then, the well plate was incubated in a 5% CO.sub.2
incubator at 37.degree. C. for 24 hours. Each of Herceptin and the
Herceptin variant antibody-MC-vc-PAB-MMAE conjugate produced in the
above Example was diluted in medium, and then added to each well of
the plate at various concentrations of 66.7 nM, 33.3 nM, 6.7 nM,
3.3 nM, 0.67 nM, 0.33 nM, 0.067 nM and 0.0067 nM. In addition,
medium (having no drug) was added to a control wells for negative
control. After incubation for 5 days, 20 .mu.l of CellTiter
96-AQueous One Solution reagent [MTS-based assay; measuring cell
proliferation by the amount of purple formazan formed by MTS due to
the dehydrogenase of viable cells] was added to each well, followed
by incubation in an incubator at 37.degree. C. for 2 hours. The
absorbance of each well at 490 nm was measured by a
spectrophotometer to determine the cell viability (%). As a result,
all of the HR-Cys-MC-vc-PAB-MMAE, HR-Cys-Gly-Cys-MC-vc-PAB-MMAE,
HR-M2(Cys)-MC-vc-PAB-MMAE, HR-M(Cys)-MC-vc-PAB-MMAE,
HR-M2L(Cys)-MC-vc-PAB-MMAE and HR-Z(Cys)-MC-vc-PAB-MMAE showed
excellent cell proliferation inhibitory ability compared to the
parent antibody Herceptin. As shown in FIG. 6, the IC50 value of
HR-M2(Cys)-MC-vc-PAB-MMAE was at least 5 times lower than that of
the parent antibody Herceptin (the median value between the highest
and the lowest values was taken for the IC50 for Herceptin because
the viability in the case of Herceptin was not lowered to 50% or
below). Also, the cell viability at high concentrations was reduced
by about 85% for the antibody-drug conjugate, but was reduced only
by about 40% for the parent antibody Herceptin. These results
indicate that the antibody-drug conjugate has a very high
cytotoxicity and a very low IC50 value compared to the parent
antibody.
Example 7: In Vitro Assay of Caspase 3/7 Activation
[0182] SK-BR3 cells were diluted with 10% FBS-containing RPMI 1640
medium, and 100 .mu.l of the cell diluted suspension was added to
each well of a 96-well plate at a density of 1.times.10.sup.4
cells/well. Then, the 96-well plate was incubated in a 5% CO.sub.2
incubator at 37.degree. C. for 24 hours. Each of Herceptin and the
modified antibody-drug conjugates produced in the above Example was
diluted in medium, and then added to each well of the plate at
various concentrations of 66.7 nM, 33.3 nM, 6.7 nM, 3.3 nM, 0.67
nM, 0.33 nM, 0.067 nM and 0.0067 nM. Also medium (having no drug)
was added to a control well for negative control. After incubation
for 48 hours, 100 .mu.l of Caspase-Glo 3/7 reagent [Caspase-Glo 3/7
assay; measurement of luminescence resulting from the degradation
of a caspase substrate by caspase 3/7 activity formed in cells in
which apoptosis is induced by the caspase pathway] was added to
each well, followed by incubation at room temperature for 30
minutes. Luminescence was measured by a luminometer.
[0183] As shown in FIG. 7, in the cells treated with the parent
antibody Herceptin, little or no caspase activity was observed, but
in the cells treated with HR-Cys2-MMAE, 3/7 activity increased as
the concentration of HR-Cys2-MMAE increased. These results suggest
that the MMAE drug released from HR-Cys2-MMAE delivered into the
cells induces apoptosis through the caspase pathway, unlike
Herceptin.
[0184] In addition, as shown in FIG. 8, in the cells treated with
Herceptin, little or no caspase activity appeared, but in the cells
treated with HR-M2(Cys)-MC-vc-PAB-MMAE, caspase activity increased
as the concentration of HR-M2(Cys)-MC-vc-PAB-MMAE increased. These
results indicate that the MMAE drug released from
HR-M2(Cys)-MC-vc-PAB-MMAE delivered into the cells induce apoptosis
through the caspase pathway, unlike Herceptin.
INDUSTRIAL APPLICABILITY
[0185] As described above, the modified antibody of the present
invention and the modified antibody-drug conjugate comprising the
same can accurately deliver a drug to a target cell due to its high
specificity to antigen, and thus can increase the therapeutic
effect of the drug. In addition, it can increase the usability of
drugs, particularly anticancer agents, the use of which is limited
due to their toxicity, despite their high efficacy.
Sequence CWU 1
1
102123PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 1Tyr Lys Cys Lys Gln Cys Gly Lys Ala Phe Gly Cys Pro Ser
Asn Leu 1 5 10 15 Arg Arg His Gly Arg Thr His 20 224PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 2Tyr Gln Cys
Asn Ile Cys Gly Gly Lys Cys Phe Ser Cys Asn Ser Asn 1 5 10 15 Leu
His Arg His Gln Arg Thr His 20 323PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 3Tyr Ser Cys Gly Ile Cys Gly
Lys Ser Phe Ser Asp Ser Ser Ala Lys 1 5 10 15 Arg Arg His Cys Ile
Leu His 20 423PRTArtificial Sequencemetal ion binding motif of zinc
finger protein 4Tyr Thr Cys Ser Asp Cys Gly Lys Ala Phe Arg Asp Lys
Ser Cys Leu 1 5 10 15 Asn Arg His Arg Arg Thr His 20
524PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 5Tyr Arg Cys Lys Tyr Cys Asp Arg Ser Phe Ser Asp Ser Ser
Asn Leu 1 5 10 15 Gln Arg His Val Arg Asn Ile His 20
623PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 6Tyr Lys Cys Lys Glu Cys Gly Lys Ala Phe Asn His Ser Ser
Asn Phe 1 5 10 15 Asn Lys His His Arg Ile His 20 723PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 7Phe Lys Cys
Pro Val Cys Gly Lys Ala Phe Arg His Ser Ser Ser Leu 1 5 10 15 Val
Arg His Gln Arg Thr His 20 825PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 8Tyr Arg Cys Lys Tyr Cys Cys
Asp Arg Ser Phe Ser Ile Ser Ser Asn 1 5 10 15 Leu Gln Arg His Val
Arg Asn Ile His 20 25 923PRTArtificial Sequencemetal ion binding
motif of zinc finger protein 9Tyr Glu Cys Asp His Cys Gly Lys Ala
Phe Ser Ile Gly Ser Asn Leu 1 5 10 15 Asn Val His Arg Arg Ile His
20 1023PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 10Tyr Gly Cys His Leu Cys Cys Lys Ala Phe Ser Lys Ser Ser
Asn Leu 1 5 10 15 Arg Arg His Glu Met Ile His 20 1123PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 11Tyr Lys
Cys Lys Glu Cys Gly Gln Ala Phe Arg Gln Arg Ala His Leu 1 5 10 15
Ile Arg His His Lys Leu His 20 1223PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 12Tyr Lys Cys His Gln Cys Gly
Lys Ala Phe Ile Gln Ser Phe Asn Leu 1 5 10 15 Arg Arg His Glu Arg
Thr His 20 1323PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 13Phe Gln Cys Asn Gln Cys Gly Ala Ser Phe Thr
Gln Lys Gly Asn Leu 1 5 10 15 Asn Arg His Ile Lys Leu His 20
1423PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 14Tyr Thr Cys Ser Tyr Cys Gly Lys Ser Phe Thr Gln Ser Asn
Thr Leu 1 5 10 15 Lys Gln His Thr Arg Ile His 20 1522PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 15Tyr Ala
Cys His Leu Cys Gly Lys Ala Phe Thr Gln Ser Ser His Arg 1 5 10 15
Arg His Glu Lys Thr His 20 1623PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 16Tyr Lys Cys Gly Gln Cys Gly
Lys Phe Tyr Ser Gln Val Ser His Leu 1 5 10 15 Thr Arg His Gln Lys
Ile His 20 1723PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 17Tyr Ala Cys His Leu Cys Gly Lys Ala Phe Thr
Gln Cys Ser His Leu 1 5 10 15 Arg Arg His Glu Lys Thr His 20
1823PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 18Tyr Ala Cys His Leu Cys Ala Lys Ala Phe Ile Gln Cys Ser
His Leu 1 5 10 15 Arg Arg His Glu Lys Thr His 20 1923PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 19Tyr Val
Cys Arg Glu Cys Gly Arg Gly Phe Arg Gln His Ser His Leu 1 5 10 15
Val Arg His Lys Arg Thr His 20 2024PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 20Tyr Lys Cys Glu Glu Cys Glu
Gly Lys Ala Phe Arg Gln Ser Ser His 1 5 10 15 Leu Thr Thr His Lys
Ile Ile His 20 2123PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 21Tyr Glu Cys Asp His Cys Gly Lys Ser Phe Ser
Gln Ser Ser His Leu 1 5 10 15 Asn Val His Lys Arg Thr His 20
2223PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 22Tyr Met Cys Ser Glu Cys Gly Arg Gly Phe Ser Gln Lys Ser
Asn Leu 1 5 10 15 Thr Ile His Gln Arg Thr His 20 2323PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 23Tyr Lys
Cys Glu Glu Cys Gly Lys Ala Phe Thr Gln Ser Ser Asn Leu 1 5 10 15
Thr Lys His Lys Lys Ile His 20 2423PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 24Phe Glu Cys Lys Asp Cys Gly
Lys Ala Phe Ile Gln Lys Ser Asn Leu 1 5 10 15 Ile Arg His Gln Arg
Thr His 20 2523PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 25Tyr Val Cys Arg Glu Cys Arg Arg Gly Phe Ser
Gln Lys Ser Asn Leu 1 5 10 15 Ile Arg His Gln Arg Thr His 20
2623PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 26Tyr Glu Cys Glu Lys Cys Gly Lys Ala Phe Asn Gln Ser Ser
Asn Leu 1 5 10 15 Thr Arg His Lys Lys Ser His 20 2723PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 27Tyr Glu
Cys Val Gln Cys Gly Lys Ser Tyr Ser Gln Ser Ser Asn Leu 1 5 10 15
Phe Arg His Gln Arg Arg His 20 2823PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 28Tyr Glu Cys Val Gln Cys Gly
Lys Gly Phe Thr Gln Ser Ser Asn Leu 1 5 10 15 Ile Thr His Gln Arg
Val His 20 2923PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 29Tyr Glu Cys Asn Thr Cys Arg Lys Thr Phe Ser
Gln Lys Ser Asn Leu 1 5 10 15 Ile Val His Gln Arg Thr His 20
3023PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 30Tyr Val Cys Ser Lys Cys Gly Lys Ala Phe Thr Gln Ser Ser
Asn Leu 1 5 10 15 Thr Val His Gln Lys Ile His 20 3123PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 31Tyr Lys
Cys Asp Glu Cys Gly Lys Asn Phe Thr Gln Ser Ser Asn Leu 1 5 10 15
Ile Val His Lys Arg Ile His 20 3223PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 32Tyr Glu Cys Asp Val Cys Gly
Lys Thr Phe Thr Gln Lys Ser Asn Leu 1 5 10 15 Gly Val His Gln Arg
Thr His 20 3323PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 33Tyr Lys Cys Pro Asp Cys Gly Lys Ser Phe Ser
Gln Ser Ser Ser Leu 1 5 10 15 Ile Arg His Gln Arg Thr His 20
3423PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 34Tyr Glu Cys Gln Asp Cys Gly Arg Ala Phe Asn Gln Asn Ser
Ser Leu 1 5 10 15 Gly Arg His Lys Arg Thr His 20 3523PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 35Tyr Glu
Cys Asn Glu Cys Gly Lys Phe Phe Ser Gln Ser Ser Ser Leu 1 5 10 15
Ile Arg His Arg Arg Ser His 20 3623PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 36Tyr Lys Cys Glu Glu Cys Gly
Lys Ala Phe Asn Gln Ser Ser Thr Leu 1 5 10 15 Thr Arg His Lys Ile
Val His 20 3723PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 37Tyr Glu Cys Asn Glu Cys Gly Lys Ala Phe Ala
Gln Asn Ser Thr Leu 1 5 10 15 Arg Val His Gln Arg Ile His 20
3824PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 38Tyr Glu Val His Asp Cys Gly Lys Ser Phe Arg Gln Ser Thr
His Thr 1 5 10 15 Leu Thr Gln His Arg Arg Ile His 20
3923PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 39Tyr Glu Cys His Asp Cys Gly Lys Ser Phe Arg Gln Ser Thr
His Leu 1 5 10 15 Thr Arg His Arg Arg Ile His 20 4023PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 40His Lys
Cys Leu Glu Cys Gly Lys Cys Phe Ser Gln Asn Thr His Leu 1 5 10 15
Thr Arg His Gln Arg Thr His 20 4125PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 41Tyr Val Cys Asp Val Glu Gly
Cys Thr Trp Lys Phe Ala Arg Ser Asp 1 5 10 15 Glu Leu Asn Arg His
Lys Lys Arg His 20 25 4225PRTArtificial Sequencemetal ion binding
motif of zinc finger protein 42Tyr His Cys Asp Trp Asp Gly Cys Gly
Trp Lys Phe Ala Arg Ser Asp 1 5 10 15 Glu Leu Thr Arg His Tyr Arg
Lys His 20 25 4325PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 43Tyr Arg Cys Ser Trp Glu Gly Cys Glu Trp Arg
Phe Ala Arg Ser Asp 1 5 10 15 Glu Leu Thr Arg His Phe Arg Lys His
20 25 4425PRTArtificial Sequencemetal ion binding motif of zinc
finger protein 44Phe Ser Cys Ser Trp Lys Gly Cys Glu Arg Arg Phe
Ala Arg Ser Asp 1 5 10 15 Glu Leu Ser Arg His Arg Arg Thr His 20 25
4525PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 45Phe Ala Cys Ser Trp Gln Asp Cys Asn Lys Lys Phe Ala Arg
Ser Asp 1 5 10 15 Glu Leu Ala Arg His Tyr Arg Thr His 20 25
4625PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 46Tyr His Cys Asn Trp Asp Gly Cys Gly Trp Lys Phe Ala Arg
Ser Asp 1 5 10 15 Glu Leu Thr Arg His Tyr Arg Lys His 20 25
4724PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 47Phe Leu Cys Gln Tyr Cys Ala Gln Arg Phe Gly Arg Lys Asp
His Leu 1 5 10 15 Thr Arg His Met Lys His Ser His 20
4823PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 48Cys Arg Cys Asn Glu Cys Gly Lys Ser Phe Ser Arg Arg Asp
His Leu 1 5 10 15 Val Arg His Gln Arg Thr His 20 4923PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 49Phe Gln
Cys Lys Thr Cys Gln Arg Lys Phe Ser Arg Ser Asp His Leu 1 5 10 15
Lys Thr His Thr Arg Thr His 20 5023PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 50Phe Ala Cys Glu Val Cys Gly
Val Arg Phe Thr Arg Asn Asp Lys Leu 1 5 10 15 Lys Ile His Met Arg
Lys His 20 5125PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 51Tyr Val Cys Asp Val Glu Gly Cys Thr Trp Lys
Phe Ala Arg Ser Asp 1 5 10 15 Lys Leu Asn Arg His Lys Lys Arg His
20 25 5223PRTArtificial Sequencemetal ion binding motif of zinc
finger protein 52Tyr Lys Cys Met Glu Cys Gly Lys Ala Phe Asn Arg
Arg Ser His Leu 1 5 10 15 Thr Arg His Gln Arg Ile His 20
5323PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 53Tyr Ile Cys Arg Lys Cys Gly Arg Gly Phe Ser Arg Lys Ser
Asn Leu 1 5 10 15 Ile Arg His Gln Arg Thr His 20 5423PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 54Tyr Glu
Cys Lys Glu Cys Gly Lys Ala Phe Ser Ser Gly Ser Asn Phe 1 5 10 15
Thr Arg His Gln Arg Ile His 20 5523PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 55Phe His Cys Gly Tyr Cys Glu
Lys Ser Phe Ser Val Lys Asp Tyr Leu 1 5 10 15 Thr Lys His Ile Arg
Thr His 20 5623PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 56Tyr Glu Cys Asp His Cys Gly Lys Ala Phe Ser
Val Ser Ser Asn Leu 1 5 10 15 Asn Val His Arg Arg Ile His 20
5723PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 57Tyr Thr Cys Lys Gln Cys Gly Lys Ala Phe Ser Val Ser Ser
Ser Leu 1 5 10 15 Arg Arg His Glu Thr Thr His 20 5823PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 58Tyr Glu
Cys Asn Tyr Cys Gly Lys Thr Phe Ser Val Ser Ser Thr Leu 1 5 10 15
Ile Arg His Gln Arg Ile His 20 5923PRTArtificial Sequencemetal ion
binding motif of zinc finger protein 59Tyr Arg Cys Glu Glu Cys Gly
Lys Ala Phe Arg Trp Pro Ser Asn Leu 1 5 10 15 Thr Arg His Lys Arg
Ile His 20 6023PRTArtificial Sequencemetal ion binding motif of
zinc finger protein 60Phe Ala Cys Asp Ile Cys Gly Arg Lys Phe Ala
Arg Ser Asp Glu Arg 1 5 10 15 Lys Arg His Thr Lys Ile His 20
6123PRTArtificial Sequencemetal ion binding motif of zinc finger
protein 61Cys Pro Val Glu Ser Cys Asp Arg Arg Phe Ser Arg Ser Asp
Glu Leu 1 5 10 15 Thr Arg His Ile Arg Ile His 20 6221PRTArtificial
Sequencemetal ion binding motif of zinc finger protein 62Cys Asp
Ile Cys Gly Arg Lys Phe Ala Arg Ser Asp Glu Arg Lys Arg 1 5 10 15
His Thr Lys Ile His 20 6354PRTArtificial SequenceCadC protein 63Cys
Glu Ile Phe Cys Tyr Asp Glu Glu Lys Val Asn Arg Ile Gln Gly 1 5 10
15 Asp Leu Gln Thr Val Asp Ile Ser Gly Val Ser Gln Ile Leu Lys Ala
20 25 30 Ile Ala Asp Glu Asn Arg Ala Lys Ile Thr Tyr Ala Leu Cys
Gln Asp 35 40 45 Glu Glu Leu Cys Val Cys 50 6454PRTArtificial
SequenceAztR protein 64Cys Asp Thr His Leu Val His Leu Asp Asn Val
Arg Ser Ser Gln Ala 1 5 10 15 Gln Ile Leu Pro Thr Asp Lys Ala Gln
Gln Met Ala Glu Ile Phe Gly 20 25 30 Val Leu Ala Asp Thr Asn Arg
Ile Arg Leu Leu Ser Ala Leu Ala Ser 35 40 45 Ser Glu Leu Cys Val
Cys 50 6554PRTArtificial SequenceZiaR protein 65Cys Asp Gln Pro Leu
Val His Leu Glu Gln Val Arg Gln Val Gln Pro 1 5 10 15 Glu Val Met
Ser Leu Asp Gln Ala Gln Gln Met Ala Glu Phe Phe Ser 20 25 30 Ala
Leu Ala Asp Pro Ser Arg Leu Arg Leu Met Ser Ala Leu Ala Arg 35 40
45 Gln Glu Leu Cys Val Cys 50 6655PRTArtificial SequenceBxmR
protein 66Cys Asp Arg Ala His Leu Val Asp Cys Ser Arg Val Gly Asp
Ile Gln 1 5 10 15 Thr Gln Val Leu Asn Thr Ala Lys Ala Gln Arg Met
Ala Glu Phe Phe 20 25 30 Ser Leu Leu Gly Asp Ala Asn Arg Leu Arg
Val Val Ser Val Leu Ala 35 40 45 Lys Gln Glu Leu Cys Val Cys 50
55
6726PRTArtificial SequenceArsR protein 67Leu Ser Asp Glu Thr Arg
Leu Gly Ile Val Leu Leu Leu Arg Glu Met 1 5 10 15 Gly Glu Leu Cys
Val Cys Asp Leu Cys Met 20 25 6841PRTArtificial SequenceArsR
protein 68Cys Cys Thr Leu Ala Thr Gly Pro Leu Ser Ser Asp Glu Ser
Glu His 1 5 10 15 Tyr Ala Asp Leu Phe Lys Val Leu Gly Asp Pro Val
Arg Leu Arg Ile 20 25 30 Leu Ser Gln Leu Ala Ala Gly Gly Cys 35 40
6926PRTArtificial SequenceArsR protein 69Tyr Arg Ala Ala Met Pro
Val Val Arg Ala Leu Val Ala Tyr Leu Thr 1 5 10 15 Glu Asn Cys Cys
His Gly Thr Arg Asp Cys 20 25 7046PRTArtificial SequenceCmtR
protein 70Cys Leu Arg Gly Cys Gly Leu Val Val Ala Thr Tyr Glu Gly
Arg Gln 1 5 10 15 Val Arg Tyr Ala Leu Ala Asp Ser His Leu Ala Arg
Ala Leu Gly Glu 20 25 30 Leu Val Gln Val Val Leu Ala Val Asp Thr
Asp Gln Pro Cys 35 40 45 7155PRTArtificial SequenceCmtR protein
71Cys Leu Arg Asp Cys Gly Leu Val Val Thr Val Pro Asp Gly Arg Arg 1
5 10 15 Ser Arg Tyr Glu Leu Ala Asp Glu Arg Leu Gly His Ala Leu Asp
Asp 20 25 30 Leu Arg Ala Ala Val Val Ala Val Asp Ala Asp Arg Thr
Cys Pro Asp 35 40 45 Ala Asp Glu Leu Glu Cys Cys 50 55
7231PRTArtificial SequenceE.coli ZntA 72Val Ser Gly Met Asp Cys Ala
Ala Cys Ala Arg Lys Val Glu Asn Ala 1 5 10 15 Val Arg Gln Leu Ala
Gly Val Asn Gln Val Gln Val Leu Phe Ala 20 25 30 7331PRTArtificial
SequenceTn501 MerP 73Val Pro Gly Met Thr Cys Ser Ala Cys Pro Ile
Thr Val Lys Lys Ala 1 5 10 15 Ile Ser Glu Val Glu Gly Val Ser Lys
Val Asp Val Thr Phe Glu 20 25 30 7430PRTArtificial SequenceTn501
MerA 74Ile Thr Gly Met Thr Cys Asp Ser Cys Ala Ala His Val Lys Glu
Ala 1 5 10 15 Leu Glu Lys Val Pro Gly Val Gln Ser Ala Leu Val Ser
Tyr 20 25 30 7531PRTArtificial SequenceS.aureus CadA 75Val Gln Gly
Phe Thr Cys Ala Asn Cys Ala Gly Lys Phe Glu Lys Asn 1 5 10 15 Val
Lys Lys Ile Pro Gly Val Gln Asp Ala Lys Val Asn Phe Gly 20 25 30
7631PRTArtificial SequenceHuman Menkes 76Val Glu Gly Met Thr Cys
Asn Ser Cys Val Trp Thr Ile Glu Gln Gln 1 5 10 15 Ile Gly Lys Val
Asn Gly Glu His His Ile Lys Val Ser Leu Glu 20 25 30
7729PRTArtificial SequenceYeast Atx1 77Val Val Met Thr Cys Ser Gly
Cys Ser Gly Ala Val Asn Lys Val Leu 1 5 10 15 Thr Lys Leu Glu Pro
Asp Val Ser Lys Ile Asp Ile Ser 20 25 7824PRTArtificial SequenceRat
Wilsons 78Gly Met Thr Cys Ala Ser Cys Val Ala Asn Ile Glu Arg Asn
Leu Arg 1 5 10 15 Arg Glu Glu Gly Ile Tyr Ser Val 20
7930PRTArtificial SequenceHum Wilsons 79Tyr Glu Gly Met Thr Cys Gln
Ser Cys Val Ser Ser Ile Glu Gly Lys 1 5 10 15 Tyr Arg Lys Leu Gln
Gly Val Val Arg Tyr Lys Val Ser Leu 20 25 30 8029PRTArtificial
SequenceRice Cu ATPase 80Gly Met Ser Cys Gln Gly Cys Ala Gly Ala
Val Arg Arg Val Leu Thr 1 5 10 15 Lys Met Glu Gly Val Glu Thr Phe
Asp Ile Asp Met Glu 20 25 8131PRTArtificial SequenceH.pylori Cu
ATPase 81Val Pro Ser Ile Thr Cys Ser His Cys Val Asp Lys Ile Glu
Lys Phe 1 5 10 15 Val Gly Glu Ile Glu Gly Val Ser Phe Ile Asp Ala
Asn Val Glu 20 25 30 8252PRTArtificial SequenceRan1 82Val Thr Gly
Met Thr Cys Ala Ala Cys Ser Asn Ser Val Glu Ala Ala 1 5 10 15 Leu
Met Asn Val Asn Gly Val Asp Val Gly Gly Met Thr Cys Gly Gly 20 25
30 Cys Ser Ala Ser Val Lys Lys Leu Leu Glu Ser Gln Pro Cys Val Ala
35 40 45 Ser Ala Ser Val 50 8323PRTArtificial SequenceCpx89 83Val
Ser Gly Met Val Cys Ala Ala Cys Ser Thr Ala Val Glu Asn Ala 1 5 10
15 Leu Leu Ser Cys Ser Gly Val 20 8422PRTArtificial SequencePaa1
84Asp Val Gly Gly Met Thr Cys Gly Gly Cys Ser Ala Ser Val Lys Lys 1
5 10 15 Ile Leu Glu Ser Gln Pro 20 8528PRTArtificial
SequenceCpx1184 85Asp Val Gly Gly Met Lys Cys Gly Gly Cys Val Glu
His Val Lys Lys 1 5 10 15 Ile Leu Glu Glu Gln Phe Gly Val Thr Ser
Ala Ser 20 25 8626PRTArtificial SequenceMetal ion binding motif
86Pro Tyr Lys Cys Pro Glu Cys Gly Lys Ser Phe Ser Gln Lys Ser Ala 1
5 10 15 Leu Val Lys His Gln Arg Thr His Thr Cys 20 25
8726PRTArtificial SequenceMetal ion binding motif 87Pro Tyr Lys Cys
Pro Glu Cys Gly Lys Ser Phe Ser Gln Lys Ser Ala 1 5 10 15 Leu Val
Lys His Gln Arg Thr His Thr Met 20 25 8826PRTArtificial
SequenceMetal ion binding motif 88Pro Tyr Lys Cys Pro Glu Cys Gly
Lys Ser Phe Ser Gln Lys Ser Ala 1 5 10 15 Leu Val Lys His Gln Arg
Thr His Thr Cys 20 25 8926PRTArtificial SequenceMetal ion binding
motif 89Pro Tyr Lys Cys Pro Glu Cys Gly Lys Ser Phe Ser Gln Lys Ser
Ala 1 5 10 15 Leu Val Lys His Gln Arg Thr His Thr His 20 25
9026PRTArtificial SequenceMetal ion binding motif 90Pro Tyr Lys Cys
Pro Glu Cys Gly Lys Ser Phe Ser Gln Lys Ser Ala 1 5 10 15 Leu Val
Lys His Gln Arg Thr His Thr His 20 25 9122PRTArtificial
SequenceMetal ion binding motif 91Pro Tyr Lys Cys Pro Glu Cys Gly
Lys Ser Phe Ser Gln Lys Ser Ala 1 5 10 15 Leu Val Lys His Gln Arg
20 9230PRTArtificial Sequencemetal ion-binding peptide motif 92Gly
Leu Lys Ala Leu Glu Glu Lys Cys Lys Ala Leu Glu Glu Lys Leu 1 5 10
15 Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Gly 20 25 30
9330PRTArtificial Sequencemetal ion-binding peptide motif 93Gly Leu
Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Leu 1 5 10 15
Lys Ala Cys Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Gly 20 25 30
9430PRTArtificial Sequencemetal ion-binding peptide motif 94Gly Leu
Lys Ala Leu Glu Glu Lys Cys Lys Ala Leu Glu Glu Lys Leu 1 5 10 15
Lys Ala Cys Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Gly 20 25 30
9530PRTArtificial Sequencemetal ion-binding peptide motif 95Gly Leu
Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Cys 1 5 10 15
Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Gly 20 25 30
9630PRTArtificial Sequencemetal ion-binding peptide motif 96Gly Leu
Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Leu 1 5 10 15
Lys Ala Leu Glu Glu Lys Cys Lys Ala Leu Glu Glu Lys Gly 20 25 30
9737PRTArtificial Sequencemetal ion-binding peptide motif 97Gly Leu
Lys Ala Leu Glu Glu Lys Leu Lys Ala Leu Glu Glu Lys Leu 1 5 10 15
Lys Ala Leu Glu Glu Lys Leu Lys Ala Ala Glu Glu Lys Cys Lys Ala 20
25 30 Leu Glu Glu Lys Gly 35 9837PRTArtificial Sequencemetal
ion-binding peptide motif 98Gly Leu Lys Ala Leu Glu Glu Lys Leu Lys
Ala Leu Glu Glu Lys Cys 1 5 10 15 Lys Ala Leu Glu Glu Lys Leu Lys
Ala Ala Glu Glu Lys Cys Lys Ala 20 25 30 Leu Glu Glu Lys Gly 35
9934PRTArtificial Sequencemetal ion-binding peptide motif 99Leu Tyr
Ala Leu Glu Lys Glu Leu Gly Ala Leu Glu Lys Glu Leu Ala 1 5 10 15
Cys Leu Glu Lys Glu Leu Gly Ala Leu Glu Lys Glu Leu Tyr Ala Leu 20
25 30 Glu Lys 10035PRTArtificial Sequencemetal ion-binding peptide
motif 100Lys Leu Tyr Ala Leu Lys Glu Lys Leu Gly Ala Leu Lys Glu
Lys Leu 1 5 10 15 Ala Cys Leu Lys Glu Lys Leu Gly Ala Leu Lys Glu
Lys Leu Tyr Ala 20 25 30 Leu Lys Glu 35 10135PRTArtificial
Sequencemetal ion-binding peptide motif 101Glu Leu Tyr Ala Leu Glu
Lys Glu Leu Gly Ala Leu Glu Lys Glu Leu 1 5 10 15 Ala Cys Leu Lys
Glu Lys Leu Gly Ala Leu Lys Glu Lys Leu Tyr Ala 20 25 30 Leu Lys
Glu 35 10235PRTArtificial Sequencemetal ion-binding peptide motif
102Lys Leu Tyr Ala Leu Lys Glu Lys Leu Gly Ala Leu Lys Glu Lys Leu
1 5 10 15 Ala Cys Leu Glu Lys Glu Leu Gly Ala Leu Glu Lys Glu Leu
Tyr Ala 20 25 30 Leu Glu Lys 35
* * * * *
References