title: HgeTx1, the first K+-channel specific toxin characterized from the venom of the scorpion Hadrurus gertschi Soleglad.
abstract: A novel toxin was identified, purified and characterized from the venom of the Mexican scorpion Hadrurus gertschi (abbreviated HgeTx1). It has a molecular mass of 3950 atomic mass units (a.m.u.) and contains 36 amino acids with four disulfide bridges established between Cys1-Cys5, Cys2-Cys6, Cys3-Cys7 and Cys4-Cys8. It blocks reversibly the Shaker B K(+)-channels with a Kd of 52nM. HgeTx1 shares 60%, 45% and 40% sequence identity, respectively, with Heterometrus spinnifer toxin1 (HsTX1), Scorpio maurus K(+)-toxin (maurotoxin) and Pandinus imperator toxin1 (Pi1), all four-disulfide bridged toxins. It is 57-58% identical with the other scorpion K(+)-channel toxins that contain only three disulfide bridges. Sequence comparison, chain length and number of disulfide bridges analysis classify HgeTx1 into subfamily 6 of the alpha-KTx scorpion toxins (systematic name: alpha-KTx 6.14).
authors.affiliation: Department of Physiological Sciences, Institute of Biological Sciences, University of Brasilia, Brasilia, DF 70910-900, Brazil.
authors.forename: Elisabeth F
authors.initials: EF
authors.lastname: Schwartz
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Schwartz
authors.forename: Froylan
authors.initials: F
authors.lastname: Gómez-Lagunas
authors.forename: Fernando Z
authors.initials: FZ
authors.lastname: Zamudio
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D007313:Insecta / Q000166:cytology; D008969:Molecular Sequence Data; D026902:Potassium Channel Blockers / Q000737:chemistry* / Q000302:isolation & purification; D012604:Scorpion Venoms / Q000737:chemistry* / Q000302:isolation & purification; D012605:Scorpions / Q000737:chemistry; D016415:Sequence Alignment; D051637:Shaker Superfamily of Potassium Channels / Q000037:antagonists & inhibitors*
chemical_list: D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; D051637:Shaker Superfamily of Potassium Channels