title: A novel short-chain peptide BmKX from the Chinese scorpion Buthus martensi Karsch, sequencing, gene cloning and structure determination.
abstract: Scorpion venom is a rich source of bioactive peptides. From the venom of Chinese scorpion Buthus martensi Karsch (BmK), a novel short chain peptide BmKX of 31-amino acid residues was purified, and its amino acid sequence and gene structure were determined. The gene of BmKX was composed of two exons interrupted by an 86-bp intron at the codon-7 upstream of the mature peptide. Although its gene structure is similar to those of other known scorpion toxins, its amino acid sequence, especially the cysteine framework, is different from those of all other known subfamilies of short-chain scorpion toxins. The solution structure of BmKX, determined with two-dimensional NMR spectroscopy, shows that BmKX also forms a typical cysteine-stabilized alpha/beta scaffold adopted by most short-chain scorpion toxins, consisting of a short 3(10)-helix and a two-stranded antiparallel beta-sheet, and the short N-terminal segment forms a pseudo-strand of the beta-sheet. However, the orientation between the helix and the beta-sheet is significantly different from the others, which might be the reason for its unique but still unclear physiological function.
authors.affiliation: Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Yue-Yang Road 320, Shanghai 200031, People's Republic of China.
authors.forename: Chun-guang
authors.initials: CG
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Cai
authors.forename: Wuyuan
authors.initials: W
authors.lastname: Lu
authors.forename: Jihui
authors.initials: J
authors.lastname: Wu
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Xu
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Shi
authors.forename: Cheng-wu
authors.initials: CW
authors.lastname: Chi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002681:China; D003001:Cloning, Molecular; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D017433:Protein Structure, Secondary; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics; D012605:Scorpions; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D010455:Peptides; D012604:Scorpion Venoms