title: Purification, structure-function analysis, and molecular characterization of novel linear peptides from scorpion Opisthacanthus madagascariensis.
abstract: In the previous report [Biochem. Biophys. Res. Commun. 286 (2001) 820], we described a novel short linear peptide, IsCT, with cytolytic activity isolated from the venom of scorpion Opisthacanthus madagascariensis. From the same scorpion venom, we further purified and characterized three short linear peptides named IsCT2, IsCTf, and IsCT2f that shared high homology with IsCT, while with different C-terminal areas between IsCT/IsCT2 and IsCTf/IsCT2f. Structure-activity relationship was analyzed by performing vivo and vitro assays and circular dichroism spectroscopy. Like IsCT, IsCT2 showed broad activity spectra against microbes (Gram positive and negative bacteria as well as fungi) and relatively weak hemolytic activity against sheep red blood cells. It adopts an amphipathic alpha-helical structure in aqueous TFE and is able to disrupt the artificial membrane. However, the other two peptides IsCTf and IsCT2f showed no activity in antimicrobial or hemolytic assay. Furthermore, IsCTf and IsCT2f cannot form amphipathic alpha-helix while demonstrating random coil structure in aqueous TFE, which might result in their lost cytolytic activity. IsCTf and IsCT2f both exist in the crude venom and are proved to be enzymatic products from IsCT and IsCT2. Whether they have some other biological activity is still unclear. In addition, we got the cDNAs encoding the precursors of IsCT and IsCT2. Besides the signal peptide, they still contain an unusual acidic pro-peptide at the C-terminal that was quite different from other known precursors of scorpion venom peptides. The novel structure and biological activity of these peptides proposed them to be a new class in scorpion venom.
authors.affiliation: Suntory Institute for Bioorganic Research, Shimamoto, Osaka 618-8503, Japan. dai@sunbor.or.jp
authors.forename: Li
authors.initials: L
authors.lastname: Dai
authors.forename: Gerardo
authors.initials: G
authors.lastname: Corzo
authors.forename: Hideo
authors.initials: H
authors.lastname: Naoki
authors.forename: Marta
authors.initials: M
authors.lastname: Andriantsiferana
authors.forename: Terumi
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001483:Base Sequence; D002942:Circular Dichroism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D011485:Protein Binding; D012604:Scorpion Venoms / Q000737:chemistry* / Q000302:isolation & purification; D012605:Scorpions; D012756:Sheep; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D018076:DNA, Complementary; C435485:IsCT protein, Opisthacanthus madagascariensis; C459100:IsCT2 protein, Opisthacanthus madagascariensis; D010455:Peptides; D012604:Scorpion Venoms