title: Molecular cloning and sequencing of two 'short chain' and two 'long chain' K(+) channel-blocking peptides from the Chinese scorpion Buthus martensii Karsch.
abstract: Five full-length cDNAs encoding the precursors of two 'short chain' scorpion non-toxic peptides active on Ca(2+)-activated K(+) channels (BmP02 and BmP03) and two novel putative long chain K(+) channel-blocking peptides (named BmTXKbeta and BmTXKbeta2) were first isolated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch (BmK). BmTXKbeta2 showed a high similarity with AaTXKbeta, while BmTXKbeta was completely different in the deduced primary structure from the long chain and short chain scorpion toxins already characterized. Thus, BmTXKbeta expands the scorpion long chain K(+) channel-blocking peptide family. Although little sequence similarity exists between the above two short and two long peptides, they are similar at the positions of six cysteines, suggesting that they should all share a similar scaffold composed of an alpha-helix and a three-stranded beta-sheet.
authors.affiliation: Dept. of Virology and Molecular Biology, School of Life Sciences, Wuhan University, Wuhan, China. wxli@whu.edu.cn
authors.forename: S
authors.initials: S
authors.lastname: Zhu
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.forename: X
authors.initials: X
authors.lastname: Zeng
authors.forename: D
authors.initials: D
authors.lastname: Jiang
authors.forename: X
authors.initials: X
authors.lastname: Mao
authors.forename: H
authors.initials: H
authors.lastname: Liu
mesh_terms: D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D026902:Potassium Channel Blockers; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
chemical_list: D020413:3' Untranslated Regions; C106378:BmP02 toxin; C106379:BmP03 toxin; C121628:BmTXKbeta1 protein, Buthus martensii; C121629:BmTXKbeta2 peptide; D018076:DNA, Complementary; D010455:Peptides; D026902:Potassium Channel Blockers; D011498:Protein Precursors; D012604:Scorpion Venoms