Snake venom metalloproteinases: structure/function relationships studies using monoclonal antibodies.

Snake Venom Metalloproteinases (SVMPs) are synthesized as zymogens and undergo proteolytic processing resulting in a variety of multifunctional proteins. Jararhagin is a P-III SVMP, isolated from the venom of Bothrops jararaca, comprising metalloproteinase, disintegrin-like and cysteine-rich domains. The catalytic domain is responsible for the hemorrhagic activity. The disintegrin-like/cysteine-rich domains block alpha2beta1 integrin binding to collagen and apparently enhance the hemorrhagic activity of SVMPs. The relevance of disintegrin-like domain is described in this paper using a series of mouse anti-jararhagin monoclonal antibodies (MAJar 1-7). MAJar 3 was the only antibody able to completely neutralize jararhagin hemorrhagic activity. Neutralization of catalytic activity was partial by incubation with MAJar 1. MAJars 1 and 3 efficiently neutralized jararhagin binding to collagen with IC50 of 330 and 8.4 nM, respectively. MAJars 1 and 3 recognized the C-terminal portion of the disintegrin domain, which is apparently in conformational proximity with the catalytic domain according to additivity tests. These data suggest that disintegrin-like domain epitopes are in close contact with catalytic site or functionally modulate the expression of hemorrhagic activity in SVMPs.