title: Identification of a novel class of conotoxins defined as V-conotoxins with a unique cysteine pattern and signal peptide sequence.
abstract: Cone snails are predatory gastropod mollusks distributed in all tropical marine habitats with a highly sophisticated defense strategy using small peptides in their venoms. Here, we report the discovery and initial characterization of the V-superfamily conotoxins. A novel conotoxin vi15a was purified from the venom of a worm-hunting species Conus virgo. The sequence of vi15a was determined to have a unique arrangement of cysteine residues (C-C-CC-C-C-C-C), which defines the new V-superfamily conotoxins. The cDNA of vi15a was cloned with RACE method. Its unique signal peptide sequence led to the cloning of another V-superfamily conotoxin, Vt15.1, from Conus vitulinus. These results, as well as the existence of Lt15.1 from Conus litteratus and ca15a from Conus caracteristicus with the same cysteine pattern, suggest that V-superfamily might be a large and diverse group of peptides widely distributed in different Conus species. Like other eight Cys-containing toxins, V-superfamily conotoxins might also adopt an "ICK+1" disulfide bond connectivity. The identification of this novel class of conotoxins will certainly improve our understanding of the structure diversity of disulfide rich toxins.
authors.affiliation: Institute of Protein Research, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Can
authors.initials: C
authors.lastname: Peng
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Shao
authors.forename: Chengwu
authors.initials: C
authors.lastname: Chi
authors.forename: Chunguang
authors.initials: C
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020029:Base Pairing; D001483:Base Sequence; D003001:Cloning, Molecular; D020916:Conotoxins / Q000737:chemistry* / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D016384:Consensus Sequence; D052078:Conus Snail / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry*; D018076:DNA, Complementary / Q000235:genetics; D004220:Disulfides / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D013045:Species Specificity
chemical_list: D020916:Conotoxins; D018076:DNA, Complementary; D004220:Disulfides; D021382:Protein Sorting Signals; D003545:Cysteine