title: Cytolytic and K+ channel blocking activities of beta-KTx and scorpine-like peptides purified from scorpion venoms.
abstract: Among the scorpion venom components whose function are poorly known or even show contrasting pharmacological results are those called "orphan peptides". The most widely distributed are named beta-KTx or scorpine-like peptides. They contain three disulfide bridges with two recognizable domains: a freely moving N-terminal amino acid sequence and a tightly folded C-terminal region with a cysteine-stabilized alpha/beta (CS-alphabeta) motif. Four such peptides and three cloned genes are reported here. They were assayed for their cytolytic, antimicrobial and K (+) channel-blocking activities. Two main characteristics were found: the existence of an unusual structural and functional diversity, whereby the full-length peptide can lyse cells or kill microorganisms, and a C-terminal domain containing the CS-alphabeta motif that can block K (+) channels. Furthermore, sequence analyses and phylogenetic reconstructions are used to discuss the evolution of this type of peptide and to highlight the versatility of the CS-alphabeta structures.
authors.affiliation: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Avenida Universidad 2001, Cuernavaca, 62210, Mexico.
authors.forename: E
authors.initials: E
authors.lastname: Diego-García
authors.forename: Y
authors.initials: Y
authors.lastname: Abdel-Mottaleb
authors.forename: E F
authors.initials: EF
authors.lastname: Schwartz
authors.forename: R C Rodríguez
authors.initials: RC
authors.lastname: de la Vega
authors.forename: J
authors.initials: J
authors.lastname: Tytgat
authors.forename: L D
authors.initials: LD
authors.lastname: Possani
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects*; D023082:Defensins / Q000737:chemistry* / Q000302:isolation & purification; D019143:Evolution, Molecular; D009498:Neurotoxins; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000302:isolation & purification / Q000494:pharmacology*; D012604:Scorpion Venoms / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D023082:Defensins; D009498:Neurotoxins; D010455:Peptides; D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; C407873:scorpine