title: A novel M-superfamily conotoxin with a unique motif from Conus vexillum.
abstract: Cone snails are tropical marine mollusks that envenomate prey with a complex mixture of neuropharmacologically active compounds for the purpose of feeding and defence, each evolved to act in a highly specific manner on different parts of the nervous system. Here, we report the peptide purification, molecular cloning, chemical synthesis, and functional characterization of a structurally unique toxin isolated from the venom of Conus vexillum. The novel peptide, designated Vx2, was composed of 21 amino acid residues cross-linked by 3 disulfide bonds (WIDPSHYCCCGGGCTDDCVNC). Intriguingly, its mature peptide sequence shows low level of similarity with other identified conotoxins, and its unique motif (-CCCGGGC-) was not reported in other Conus peptides. However, its signal peptide sequence shares high similarity with those of the M-superfamily conotoxins. Hence, Vx2 could be classified into a new family of the M-superfamily.
authors.affiliation: Shanghai Institute of Biochemistry and Cell Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Cheng-Zhong
authors.initials: CZ
authors.lastname: Wang
authors.forename: Chen-Qi
authors.initials: CQ
authors.lastname: Xu
authors.forename: Chong-Xu
authors.initials: CX
authors.lastname: Fan
authors.forename: Xian-Dong
authors.initials: XD
authors.lastname: Dai
authors.forename: Ji-Sheng
authors.initials: JS
authors.lastname: Chen
authors.forename: Cheng-Wu
authors.initials: CW
authors.lastname: Chi
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D020916:Conotoxins / Q000737:chemistry* / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D052078:Conus Snail / Q000737:chemistry* / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D020916:Conotoxins; D018076:DNA, Complementary