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Title: Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity

Abstract

Clostridial neurotoxins are the causative agents of the neuroparalytic disease botulism and tetanus. They block neurotransmitter release through specific proteolysis of one of the three soluble N-ethylmaleimide-sensitive-factor attachment protein receptors (SNAREs) SNAP-25, syntaxin, and synaptobrevin, which constitute part of the synaptic vesicle fusion machinery. The catalytic component of the clostridial neurotoxins is their light chain (LC), a Zn2+ endopeptidase. There are seven structurally and functionally related botulinum neurotoxins (BoNTs), termed serotype A to G, and tetanus neurotoxin (TeNT). Each of them exhibits unique specificity for their target SNAREs and peptide bond(s) they cleave. The mechanisms of action for substrate recognition and target cleavage are largely unknown. Here, we report structural and biochemical studies of BoNT/C1-LC, which is unique among BoNTs in that it exhibits dual specificity toward both syntaxin and SNAP-25. A distinct pocket (S1') near the active site likely achieves the correct register for the cleavage site by only allowing Ala as the P1' residue for both SNAP-25 and syntaxin. Mutations of this SNAP-25 residue dramatically reduce enzymatic activity. The remote a-exosite that was previously identified in the complex of BoNT/A-LC and SNAP-25 is structurally conserved in BoNT/C1. However, mutagenesis experiments show that the a-exosite of BoNT/C1 plays amore » less stringent role in substrate discrimination in comparison to that of BoNT/A, which could account for its dual substrate specificity.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
953998
Report Number(s):
SLAC-REPRINT-2009-394
Journal ID: ISSN 0006-2960; BICHAW; TRN: US201004%%735
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Biochem. 46:10685,2007
Additional Journal Information:
Journal Volume: 46; Journal Issue: 37; Journal ID: ISSN 0006-2960
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CLEAVAGE; CLOSTRIDIUM BOTULINUM; DISEASES; MUTAGENESIS; MUTATIONS; PEPTIDES; POLYPEPTIDES; PROTEINS; PROTEOLYSIS; RECEPTORS; RESIDUES; SPECIFICITY; SUBSTRATES; TETANUS; TOXINS; Other,BIO, CHEM

Citation Formats

Jin, R, Sikorra, S, Stegmann, C M, Pich, A, Binz, T, and Brunger, A T. Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity. United States: N. p., 2009. Web.
Jin, R, Sikorra, S, Stegmann, C M, Pich, A, Binz, T, & Brunger, A T. Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity. United States.
Jin, R, Sikorra, S, Stegmann, C M, Pich, A, Binz, T, and Brunger, A T. Mon . "Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity". United States.
@article{osti_953998,
title = {Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity},
author = {Jin, R and Sikorra, S and Stegmann, C M and Pich, A and Binz, T and Brunger, A T},
abstractNote = {Clostridial neurotoxins are the causative agents of the neuroparalytic disease botulism and tetanus. They block neurotransmitter release through specific proteolysis of one of the three soluble N-ethylmaleimide-sensitive-factor attachment protein receptors (SNAREs) SNAP-25, syntaxin, and synaptobrevin, which constitute part of the synaptic vesicle fusion machinery. The catalytic component of the clostridial neurotoxins is their light chain (LC), a Zn2+ endopeptidase. There are seven structurally and functionally related botulinum neurotoxins (BoNTs), termed serotype A to G, and tetanus neurotoxin (TeNT). Each of them exhibits unique specificity for their target SNAREs and peptide bond(s) they cleave. The mechanisms of action for substrate recognition and target cleavage are largely unknown. Here, we report structural and biochemical studies of BoNT/C1-LC, which is unique among BoNTs in that it exhibits dual specificity toward both syntaxin and SNAP-25. A distinct pocket (S1') near the active site likely achieves the correct register for the cleavage site by only allowing Ala as the P1' residue for both SNAP-25 and syntaxin. Mutations of this SNAP-25 residue dramatically reduce enzymatic activity. The remote a-exosite that was previously identified in the complex of BoNT/A-LC and SNAP-25 is structurally conserved in BoNT/C1. However, mutagenesis experiments show that the a-exosite of BoNT/C1 plays a less stringent role in substrate discrimination in comparison to that of BoNT/A, which could account for its dual substrate specificity.},
doi = {},
journal = {Biochem. 46:10685,2007},
issn = {0006-2960},
number = 37,
volume = 46,
place = {United States},
year = {2009},
month = {6}
}