Contryphan-Vn: A novel peptide from the venom of the Mediterranean snail Conus ventricosus

Abstract The isolation, purification, and biochemical characterization of the novel peptide Contryphan-Vn, extracted from the venom of the Mediterranean marine snail Conus ventricosus, is reported. Contryphan-Vn is the first Conus peptide described from a vermivorous species and the first purified from the venom of the single Mediterranean Conus species. The amino acid sequence of Contryphan-Vn is [formula] As with other contryphans, Contryphan-Vn contains a d -tryptophan residue, is amidated at the C-terminus, and maintains the five-residue intercystine loop size. However, Contryphan-Vn differs from the known contryphans by the insertion of the Asp residue at position 2, by the lack of hydroxylation of Pro 4 , and, remarkably, by the presence of the basic residue Lys 6 within the intercystine loop. Although the biological function(s) of contryphans is still unknown, these characteristics suggest distinct molecular target(s) and/or function(s) for Contryphan-Vn.