Botulinum Neurotoxin Type C Cleaves a Single Lys-Ala Bond within the Carboxyl-terminal Region of Syntaxins (*)
- Giampietro Schiavo(1),
- Clifford C. Shone(2),
- Mark K. Bennett(3),
- Richard H. Scheller(4) and
- Cesare Montecucco(1)
- From the (1) Centro Consiglio Nazionale delle Ricerche Biomembrane and Dipartimento di Scienze Biomediche, Universit di Padova, Via Trieste 75, 35121 Padova, Italy, the
- (2) Protein Toxins Section, Centre of Applied Microbiology and Research, Porton Down, Salisbury, Wiltshire SP4 0JG, United Kingdom, the
- (3) Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and the
- (4) Howard Hughes Medical Institute, Department for Molecular and Cellular Physiology, Stanford University, Stanford, California 94305
Abstract
Botulinum neurotoxin serotype C (BoNT/C) is a 150-kDa protein produced by Clostridium botulinum, which causes animal botulism. In contrast to the other botulinum neurotoxins that contain one atom of zinc, highly purified
preparations of BoNT/C bind two atoms of zinc per toxin molecule. BoNT/C is a zinc-endopeptidase that cleaves syntaxin 1A
at the Lys
-Ala
and syntaxin 1B at the Lys
-Ala
peptide bonds, only when they are inserted into a lipid bilayer. The other Lys-Ala bond present within the carboxyl-terminal
region is not hydrolyzed. Syntaxin isoforms 2 and 3 are also cleaved by BoNT/C, while syntaxin 4 is resistant. These data
suggest that BoNT/C recognizes a specific spatial organization of syntaxin, adopted upon membrane insertion, which brings
a selected Lys-Ala peptide bond of its carboxyl-terminal region to the active site of this novel metalloproteinase.
Footnotes
-
↵* This work was supported by Telethon-Italy Grant 473. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- BoNT
-
botulinum neurotoxins
- DTT
-
dithiothreitol
- GST-syntaxin
-
recombinant glutathione S-methyltransferase syntaxin fusion protein
- OP
-
ortho-phenanthroline
- VAMP
-
vesicle-associated membrane protein
- PAGE
-
polyacrylamide gel electrophoresis
- L
-
light
- H
-
heavy.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
