title: Covalent structure and some pharmacological features of native and cleaved alpha-KTx12-1, a four disulfide-bridged toxin from Tityus serrulatus venom.
abstract: A toxin with four disulfide bridges from Tityus serrulatus venom was able to compete with 125I-kaliotoxin on rat brain synaptosomal preparations, with an IC50 of 46 nM. The obtained amino acid sequence and molecular mass are identical to the previously described butantoxin. Enzymatic cleavages in the native peptide followed by mass spectrometry peptide mapping analysis were used to determine the disulfide bridge pattern of alpha-KTx12-1. Also, after the cleavage of the first six N-terminal residues, including the unusual disulfide bridge which forms an N-terminus ring, the potency of the cleaved peptide was found to decrease about 100 fold compared with the native protein.
authors.affiliation: Laboratoire de Biochimie, Ingénierle des Protéines, UMR 6560, IFR Jean Roche, Bd Pierre Dramard, 13916 Marseille Cedex 20, France. apimenta@icb.ufmg.br
authors.forename: A M C
authors.initials: AM
authors.lastname: Pimenta
authors.forename: P
authors.initials: P
authors.lastname: Mansuelle
authors.forename: C R
authors.initials: CR
authors.lastname: Diniz
authors.forename: M F
authors.initials: MF
authors.lastname: Martin-Eauclaire
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000737:chemistry*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011485:Protein Binding; D051381:Rats; D012604:Scorpion Venoms / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D012605:Scorpions / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004220:Disulfides; D012604:Scorpion Venoms; C072276:kaliotoxin