title: Disulfide bridges and blockage of Shaker B K(+)-channels by another butantoxin peptide purified from the Argentinean scorpion Tityus trivittatus.
abstract: A peptide was isolated from the venom of the scorpion Tityus trivittatus. It is an isoform of the toxin TsTX-IV earlier described [Toxicon 37 (1999) 651] and identical to butantoxin [Arch. Biochem. Biophys. 379 (2000) 18], both isolated from the Brazilian scorpion Tityus serrulatus. This newly characterized peptide contains 40 amino acid residues with a molecular mass of [M+H(+)] 4507.0, cross-linked by four disulfide bridges, made between the cysteine pairs: Cys2-Cys5, Cys10-Cys31, Cys16-Cys36 and Cys20-Cys38. It blocks in a completely reversible manner the Shaker B K(+)-channels, with a K(d) around 660nM. It belongs to the sub-family 12 and it is now being classified as alpha-KTx 12.2.
authors.affiliation: Department of Molecular Recognition and Structural Biology, Institute of Biotechnology, National Autonomous University of Mexico, Cuernavaca, Mexico.
authors.forename: Fredy V
authors.initials: FV
authors.lastname: Coronas
authors.forename: Adolfo R
authors.initials: AR
authors.lastname: de Roodt
authors.forename: Timoteo Olamendi
authors.initials: TO
authors.lastname: Portugal
authors.forename: Fernando Z
authors.initials: FZ
authors.lastname: Zamudio
authors.forename: Cesar V F
authors.initials: CV
authors.lastname: Batista
authors.forename: Froylan
authors.initials: F
authors.lastname: Gómez-Lagunas
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry* / Q000494:pharmacology; D010455:Peptides; D026902:Potassium Channel Blockers / Q000737:chemistry* / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D020033:Protein Isoforms; D012604:Scorpion Venoms / Q000737:chemistry* / Q000494:pharmacology; D051637:Shaker Superfamily of Potassium Channels
chemical_list: D004220:Disulfides; D009498:Neurotoxins; D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D020033:Protein Isoforms; D012604:Scorpion Venoms; D051637:Shaker Superfamily of Potassium Channels; C411251:butantoxin; C119251:tityustoxin IV