title: Purification and characterization of bitiscetin, a novel von Willebrand factor modulator protein from Bitis arietans snake venom.
abstract: We have screened 20 snake venoms and purified a novel snake venom protein, named bitiscetin, from Bitis arietans venom that specifically binds to human von Willebrand factor (vWF) and induces platelet agglutination. Bitiscetin showed a heterodimeric structure composed of disulfide-linked alpha (16kDa) and beta (13kDa) subunits on SDS-PAGE and showed a basic nature with pI value of 9.1, in contrast to botrocetin (pI 4.6), a vWF modulator isolated from another snake (Bothrops jararaca) venom. Bitiscetin-induced platelet agglutination was dependent on vWF and platelet membrane glycoprotein (GP) Ib, but not on Ca2+ and GPIIb/IIIa. vWF bound to bitiscetin but not to botrocetin electroblotted to a PVDF membrane after SDS-PAGE and this binding was diminished after reduction of disulfide bonds of bitiscetin. Bitiscetin did not cross-react to anti-botrocetin monoclonal antibodies. These results suggest that bitiscetin directly interacts with vWF and requires the protein conformation for its interaction as well as botrocetin, but its interaction manner with vWF appears to be different from that of botrocetin.
authors.affiliation: Division of Biomedical Polymer Science, Fujita Health University, Aichi, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Hamako
authors.forename: T
authors.initials: T
authors.lastname: Matsui
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: K
authors.initials: K
authors.lastname: Makita
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Y
authors.initials: Y
authors.lastname: Ozeki
authors.forename: K
authors.initials: K
authors.lastname: Titani
mesh_terms: D000595:Amino Acid Sequence; D002852:Chromatography, Ion Exchange; D003435:Crotalid Venoms / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D011485:Protein Binding; D012910:Snake Venoms; D014757:Viper Venoms / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D003435:Crotalid Venoms; D010455:Peptides; D012910:Snake Venoms; D014757:Viper Venoms; D014841:von Willebrand Factor; C062186:bitistatin; C030961:botrocetin