The novel metalloproteinase atroxlysin-I from Peruvian Bothrops atrox (Jergon) snake venom acts both on blood vessel ECM and platelets

We report the isolation and structure-function relationship of a 23 kDa metalloproteinase named atroxlysin-I from the venom of the Peruvian Bothrops atrox (Jergon). Atroxlysin is a P-I metalloproteinase and contains 204 residues. Its proteolytic activity towards dimethylcasein is enhanced by Ca+2 but inhibited by EDTA, dithiothreitol, excessive Zn+2 and alpha 2-macroglobulin. Unlike other structurally homologous P-I metalloproteinases, atroxlysin-I causes hemorrhages. To examine its hemorrhagic activity mechanistically, we studied its function in vitro and in vivo. It cleaved the Ala(14)-Leu(15) and Tyr(16)-Leu(17) bonds in oxidized insulin B-chain and specifically hydrolyzed the alpha-chains of fibrin(ogen) in a dose- and time-dependent manner. Atroxlysin-I cleaved plasma fibronectin and other extracellular matrix proteins (collagens I and IV) and the triple-helical fragment CB3 of collagen IV. but did not degrade laminin-111. Complementarily, the laminin and collagen binding integrins alpha(7)beta(1) and alpha(1)beta(1) were cleaved by atroxlysin. Even without catalytic activity atroxlysin-I inhibited collagen- and ADP-triggered platelet aggregation. (C) 2010 Elsevier Inc. All rights reserved.