title: Isolation, chemical and functional characterization of several new K(+)-channel blocking peptides from the venom of the scorpion Centruroides tecomanus.
abstract: Six new peptides were isolated from the venom of the Mexican scorpion Centruroides tecomanus; their primary structures were determined and the effects on ion channels were verified by patch-clamp experiments. Four are K(+)-channel blockers of the α-KTx family, containing 32 to 39 amino acid residues, cross-linked by three disulfide bonds. They all block Kv1.2 in nanomolar concentrations and show various degree of selectivity over Kv1.1, Kv1.3, Shaker and KCa3.1 channels. One peptide has 42 amino acids cross-linked by four disulfides; it blocks ERG-channels and belongs to the γ-KTx family. The sixth peptide has only 32 amino acid residues, three disulfide bonds and has no effect on the ion-channels assayed. It also does not have antimicrobial activity. Systematic numbers were assigned (time of elution on HPLC): α-KTx 10.4 (time 24.1); α-KTx 2.15 (time 26.2); α-KTx 2.16 (time 23.8); α-KTx 2.17 (time 26.7) and γ-KTx 1.9 (elution time 29.6). A partial proteomic analysis of the short chain basic peptides of this venom, which elutes on carboxy-methyl-cellulose column fractionation, is included. The pharmacological properties of the peptides described in this study may provide valuable tools for understanding the structure-function relationship of K(+) channel blocking scorpion toxins.
authors.affiliation: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos, 62210, Mexico.
authors.forename: Timoteo
authors.initials: T
authors.lastname: Olamendi-Portugal
authors.affiliation: Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary.
authors.forename: Adam
authors.initials: A
authors.lastname: Bartok
authors.affiliation: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos, 62210, Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Zamudio-Zuñiga
authors.affiliation: Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary.
authors.forename: Andras
authors.initials: A
authors.lastname: Balajthy
authors.affiliation: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos, 62210, Mexico.
authors.forename: Baltazar
authors.initials: B
authors.lastname: Becerril
authors.affiliation: Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary; MTA-DE Cell Biology and Signaling Research Group, University of Debrecen, Egyetem tér 1, H-4032, Hungary.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Panyi
authors.affiliation: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Cuernavaca, Morelos, 62210, Mexico. Electronic address: possani@ibt.unam.mx.
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D055724:Electrophysiological Phenomena; D006801:Humans; D008800:Mexico; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D040901:Proteomics; D012604:Scorpion Venoms / Q000737:chemistry* / Q000494:pharmacology; D012605:Scorpions
chemical_list: D010455:Peptides; D026902:Potassium Channel Blockers; D012604:Scorpion Venoms
keywords: Amino acid sequence; Centruroides; Ion-channel; Scorpion toxin