title: A novel peptide from funnel web spider venom, omega-Aga-TK, selectively blocks, P-type calcium channels.
abstract: In the course of purification of omega-Aga-IVA, a specific P-type calcium channel blocker, from the venom of Agelenopsis aperta we discovered a novel peptide. This peptide, named omega-agatoxin Tsukuba (omega-Aga-TK), also blocked P-type channels and was twelve times more abundant in the venom than omega-Aga-IVA. omega-Aga-TK was purified to homogeneity by a two-step reverse-phase HPLC procedure. Its amino acid sequence is 71% identical to that of omega-Aga-IVA. omega-Aga-TK has a negatively charged N-terminus, whereas omega-Aga-IVA has a positively charged one. Electrophysiological data indicate that omega-Aga-TK is a potent and selective inhibitor of P-type channels.
authors.affiliation: Eisai Tsukuba Research Laboratories, Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Teramoto
authors.forename: M
authors.initials: M
authors.lastname: Kuwada
authors.forename: T
authors.initials: T
authors.lastname: Niidome
authors.forename: K
authors.initials: K
authors.lastname: Sawada
authors.forename: Y
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: K
authors.initials: K
authors.lastname: Katayama
mesh_terms: D060848:Agatoxins; D000595:Amino Acid Sequence; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D002478:Cells, Cultured; D006224:Cricetinae; D008969:Molecular Sequence Data; D051381:Rats; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013111:Spider Venoms / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D013112:Spiders; D020867:omega-Agatoxin IVA
chemical_list: D060848:Agatoxins; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; C083855:omega-agatoxin-Aa4b