ABSTRACT
This review largely deals with the peptide toxins elaborated by marine cone snails of the genus Conus . Each species of Conus contains in its venom 50 to 200 different peptides directed at different macromolecular targts. These include competitive antagonists of postsynaptic nicotinic receptors (a-conotoxins), blockers selective for Na+ channels in skeletal muscle (u- conotoxins), blockers of presynaptic of antagonists of postsynaptic Ca2+ channels (w-conotoxins), activators of Na+ channels (s-conotoxins), blockers of K+ channels (k-conotoxins), blockers of nicotinic receptor channels (u-conotoxins) and antagonists of NMDA receptors (cono-sleeper).The small size of the peptides (13 to 30 residues is typical) has facilitated synthesis of many of them. A very attractive feature is the highly cross-linked conserved 2 to 3 disulfide bonds which make conotoxins conformationally rigid, some of conotoxins, however, are stabilized by r-carboxyglutamates. The Structure-Activity Relationships of conotoxins and a brief perspective have been reviewed in the paper.