title: Ussuristatin 2, a novel KGD-bearing disintegrin from Agkistrodon ussuriensis venom.
abstract: Two platelet aggregation inhibitors, ussuristatin 1 (US-1) and 2 (US-2), were newly isolated from the venom of Chinese viper (Agkistrodon ussuriensis) by SP-Toyopearl 650M column chromatography and reverse-phase HPLC. The Mrs of these polypeptides were estimated to be about 8,000 by SDS-PAGE. Analytical gel filtration revealed that US-2 exists as a dimer. Both polypeptides comprised 71 amino acids, whose sequences showed high similarities to those of other disintegrins. US-1 had a typical Arg-Gly-Asp (RGD) sequence, which is responsible for blocking the binding of fibrinogen to the receptor. In US-2, the corresponding sequence was Lys-Gly-Asp (KGD). US-1 strongly suppressed platelet aggregation induced by ADP, collagen, thrombin, and epinephrine with IC50 = 17-33 nM. US-2 also inhibited the platelet aggregation, but the IC50s were about ten times higher. US-1 also dose-dependently inhibited the adhesion of human melanoma cells to fibrinogen and fibronectin, while US-2 did not inhibit the cell adhesion to fibronectin. This indicates that the KGD-bearing disintegrin is a specific inhibitor for the fibrinogen receptor.
authors.affiliation: Department of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka, 814-0180, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Oshikawa
authors.forename: S
authors.initials: S
authors.lastname: Terada
mesh_terms: D017836:Agkistrodon; D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D003435:Crotalid Venoms / Q000737:chemistry*; D019281:Dimerization; D019483:Disintegrins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D008545:Melanoma / Q000378:metabolism; D008969:Molecular Sequence Data; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D014757:Viper Venoms / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D003435:Crotalid Venoms; D019483:Disintegrins; D005353:Fibronectins; D010975:Platelet Aggregation Inhibitors; D014757:Viper Venoms; C118461:ussuristatin 1 protein, Gloydius ussuriensis; C118462:ussuristatin 2 protein, Gloydius ussuriensis; D005340:Fibrinogen