Synaptobrevin/vesicle-associated membrane protein (VAMP) of Aplysia californica: structure and proteolysis by tetanus toxin and botulinal neurotoxins type D and F.
Synaptobrevin/vesicle-associated membrane protein (VAMP) and syntaxin are potential vesicle donor and target membrane receptors of a docking complex that requires N-ethylmaleimide-sensitive factor (NSF) and soluble NSF-attachment proteins as soluble factors for vesicle fusion with target membranes. Members of this docking complex are the target of clostridial neurotoxins that act as zinc-dependent proteases. Molecular cloning of the Aplysia californica synaptobrevin cDNA revealed a 180-residue polypeptide (M(r), 19,745) with a central transmembrane region and an atypically large C-terminal intravesicular domain. This polypeptide integrates into membranes at both the co- and posttranslational level, as shown by modification of an artificially introduced N-glycosylation site. The soluble and membrane-anchored forms of synaptobrevin are cleaved by the light chains of the botulinal toxins type D and F and by tetanus toxin involving the peptide bonds Lys49-Ile50, Gln48-Lys49, and Gln66-Phe67, respectively. The active center of teh tetanus toxin light chain was identified by site-specific mutagenesis. His233, His237, Glu234, and Glu270/271 are essential to this proteolytic activity. Modification of histidine residues resulted in loss of zinc binding, whereas a replacement of Glu234 only slightly reduced the zinc content.
Yamasaki
S
S
Federal Research Center for Virus Diseases of Animals, Tübingen, Federal Republic of Germany.
Hu
Y
Y
Binz
T
T
Kalkuhl
A
A
Kurazono
H
H
Tamura
T
T
Jahn
R
R
Kandel
E
E
Niemann
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D001483:Base Sequence; D001905:Botulinum Toxins / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004247:DNA; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D050683:R-SNARE Proteins; D013744:Tetanus Toxin / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050683:R-SNARE Proteins; D013744:Tetanus Toxin; D004247:DNA; D008666:Metalloendopeptidases; D001905:Botulinum Toxins; D015032:Zinc