2g7k: Difference between revisions

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Structure of the Light Chain of Botulinum Neurotoxin, Serotype A Bound to small Molecule Inhibitors

OverviewOverview

Botulinum neurotoxin serotype A (BoNT/A, 1296 residues) is a zinc metalloprotease that cleaves SNAP25 to inhibit the fusion of neurotransmitter-carrying vesicles to the plasma membrane of peripheral neurons. BoNT/A is a disulfide-linked di-chain protein composed of an N-terminal, thermolysin-like metalloprotease light chain domain (LC/A, 448 residues) and a C-terminal heavy chain domain (848 residues) that can be divided into two subdomains, a translocation subdomain and a receptor binding subdomain. LC/A cleaves SNAP25 between residues Gln197-Arg198 and, unlike thermolysin, recognizes an extended region of SNAP25 for cleavage. The structure of a recombinant LC/A (1-425) treated with EDTA (No-Zn LC/A) was determined. The overall structure of No-Zn LC/A is similar to that reported for the holotoxin, except that it lacks the Zn ion, indicating that the role of Zn is catalytic not structural. In addition, structures of a noncatalytic mutant LC/A (Arg362Ala/Tyr365Phe) complexed with and without an inhibitor, ArgHX, were determined. The overall structure and the active site conformation for the mutant are the same as wild type. When the inhibitor binds to the active site, the carbonyl and N-hydroxyl groups form a bidentate ligand to the Zn ion and the arginine moiety binds to Asp369, suggesting that the inhibitor-bound structure mimics a catalytic intermediate with the Arg moiety binding at the P1' site. Consistent with this model, mutation of Asp369 to Ala decreases the catalytic activity of LC/A by approximately 600-fold, and the residual activity is not inhibited by ArgHX. These results provide new information on the reaction mechanism and insight into the development of strategies for small molecule inhibitors of BoNTs.

About this StructureAbout this Structure

2G7K is a Single protein structure of sequence from Clostridium botulinum. Active as Bontoxilysin, with EC number 3.4.24.69 Full crystallographic information is available from OCA.

ReferenceReference

Light chain of botulinum neurotoxin serotype A: structural resolution of a catalytic intermediate., Fu Z, Chen S, Baldwin MR, Boldt GE, Crawford A, Janda KD, Barbieri JT, Kim JJ, Biochemistry. 2006 Jul 25;45(29):8903-11. PMID:16846233

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 '''Structure of the Light Chain of Botulinum Neurotoxin, Serotype A Bound to small Molecule Inhibitors'''<br />
 ==Overview==
-Botulinum neurotoxin serotype A (BoNT/A, 1296 residues) is a zinc, metalloprotease that cleaves SNAP25 to inhibit the fusion of, neurotransmitter-carrying vesicles to the plasma membrane of peripheral, neurons. BoNT/A is a disulfide-linked di-chain protein composed of an, N-terminal, thermolysin-like metalloprotease light chain domain (LC/A, 448, residues) and a C-terminal heavy chain domain (848 residues) that can be, divided into two subdomains, a translocation subdomain and a receptor, binding subdomain. LC/A cleaves SNAP25 between residues Gln197-Arg198 and, unlike thermolysin, recognizes an extended region of SNAP25 for cleavage., The structure of a recombinant LC/A (1-425) treated with EDTA (No-Zn LC/A), was determined. The overall structure of No-Zn LC/A is similar to that, reported for the holotoxin, except that it lacks the Zn ion, indicating, that the role of Zn is catalytic not structural. In addition, structures, of a noncatalytic mutant LC/A (Arg362Ala/Tyr365Phe) complexed with and, without an inhibitor, ArgHX, were determined. The overall structure and, the active site conformation for the mutant are the same as wild type., When the inhibitor binds to the active site, the carbonyl and N-hydroxyl, groups form a bidentate ligand to the Zn ion and the arginine moiety binds, to Asp369, suggesting that the inhibitor-bound structure mimics a, catalytic intermediate with the Arg moiety binding at the P1' site., Consistent with this model, mutation of Asp369 to Ala decreases the, catalytic activity of LC/A by approximately 600-fold, and the residual, activity is not inhibited by ArgHX. These results provide new information, on the reaction mechanism and insight into the development of strategies, for small molecule inhibitors of BoNTs.
+Botulinum neurotoxin serotype A (BoNT/A, 1296 residues) is a zinc metalloprotease that cleaves SNAP25 to inhibit the fusion of neurotransmitter-carrying vesicles to the plasma membrane of peripheral neurons. BoNT/A is a disulfide-linked di-chain protein composed of an N-terminal, thermolysin-like metalloprotease light chain domain (LC/A, 448 residues) and a C-terminal heavy chain domain (848 residues) that can be divided into two subdomains, a translocation subdomain and a receptor binding subdomain. LC/A cleaves SNAP25 between residues Gln197-Arg198 and, unlike thermolysin, recognizes an extended region of SNAP25 for cleavage. The structure of a recombinant LC/A (1-425) treated with EDTA (No-Zn LC/A) was determined. The overall structure of No-Zn LC/A is similar to that reported for the holotoxin, except that it lacks the Zn ion, indicating that the role of Zn is catalytic not structural. In addition, structures of a noncatalytic mutant LC/A (Arg362Ala/Tyr365Phe) complexed with and without an inhibitor, ArgHX, were determined. The overall structure and the active site conformation for the mutant are the same as wild type. When the inhibitor binds to the active site, the carbonyl and N-hydroxyl groups form a bidentate ligand to the Zn ion and the arginine moiety binds to Asp369, suggesting that the inhibitor-bound structure mimics a catalytic intermediate with the Arg moiety binding at the P1' site. Consistent with this model, mutation of Asp369 to Ala decreases the catalytic activity of LC/A by approximately 600-fold, and the residual activity is not inhibited by ArgHX. These results provide new information on the reaction mechanism and insight into the development of strategies for small molecule inhibitors of BoNTs.
 ==About this Structure==
-G7K is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_botulinum Clostridium botulinum]. Active as [http://en.wikipedia.org/wiki/Bontoxilysin Bontoxilysin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.24.69 3.4.24.69] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2G7K OCA].
+G7K is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_botulinum Clostridium botulinum]. Active as [http://en.wikipedia.org/wiki/Bontoxilysin Bontoxilysin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.24.69 3.4.24.69] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G7K OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Clostridium botulinum]]
 [[Category: Single protein]]
-[[Category: Baldwin, M.R.]]
+[[Category: Baldwin, M R.]]
-[[Category: Barbieri, J.T.]]
+[[Category: Barbieri, J T.]]
-[[Category: Boldt, G.E.]]
+[[Category: Boldt, G E.]]
 [[Category: Crawford, A.]]
 [[Category: Fu, Z.]]
-[[Category: Janda, K.D.]]
+[[Category: Janda, K D.]]
-[[Category: Kim, J.J.P.]]
+[[Category: Kim, J J.P.]]
 [[Category: botulinum neurotoxin]]
 [[Category: snap25]]
 [[Category: zinc protease]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 11:00:41 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:28:57 2008''