α-Conotoxins (Conus spp.)

Abstract The α-conotoxins are probably the largest family of paralytic neurotoxins found in the venoms of cone snails (genus Conus), a very successful group of predatory molluscs comprising c. 500 species (Olivera et al. 1985; Myers et al. 1991). The first neurotoxin purified from Conus venoms was an α-conotoxin (α-conotoxin GI from Conus geographus venom); this peptide has 13 amino acids and two disulfide bonds (Gray et al. 1981). α-Conotoxins found in lndo-Pacific fish-hunting cone snails are among the major peptidic components used to paralyse fish prey, and have the consensus sequence shown in Fig. 1. Even the unusual α-conotoxin, S11, which has three disulfide bonds, fits the consensus sequence (Ramilo et al. 1992).