home *** CD-ROM | disk | FTP | other *** search
- **************************
- * Snake toxins signature *
- **************************
-
- Snake toxins belong to a family of proteins [1,2,3] which groups short and
- long neurotoxins, cytotoxins and short toxins, as well as a other miscellanous
- venom peptides. Most of these toxins act by binding to the nicotinic
- acetylcholine receptors in the postsynaptic membrane of skeletal muscles and
- prevent the binding of acetylcholine, thereby blocking the excitation of
- muscles.
-
- Snake toxins are proteins that consist of sixty to seventy five amino acids.
- Among the invariant residues are eight cysteines all involved in disulfide
- bonds. We have developed a signature pattern which includes three of these
- cysteines as well as a conserved proline thought to be important for the
- maintenance of the tertiary structure. The first cysteine in the pattern is
- linked to the second one by a disulfide bond.
-
- -Consensus pattern: C-P-x(6,8)-[LIVYST]-x-C-C
- [The three C's are involved in disulfide bonds]
- -Sequences known to belong to this class detected by the pattern: Most of the
- snake toxins are detected except for fasciatoxin, which is an atypical short
- neurotoxin, and eight toxins which have a very low activity.
- -Other sequence(s) detected in SWISS-PROT: 13.
- -Last update: December 1992 / Text revised.
-
- [ 1] Dufton M.J.
- J. Mol. Evol. 20:128-134(1984).
- [ 2] Endo T., Tamiya N.
- (In) Snake toxins, Harvey A.L., Ed., pp165-222, Pergamon Press, New-York,
- (1991).
- [ 3] Mebs D., Claus I.
- (In) Snake toxins, Harvey A.L., Ed., pp425-447, Pergamon Press, New-York,
- (1991).
-