These include the Zn2+-binding motif and the structural Met-Turn sequence that serves as a scaffold to stabilize the histidine residues involved in catalysis (Bode et al., 1993; Stöcker et al., 1995). Linked to the C-terminus
of catalytic domain, jararhagin contain two non-catalytic domains: the disintegrin-like domain conserves the cysteinyl residues in position generally found in the RGD-disintegrins, important integrin-ligands found in viper venoms (Huang, 1998). However, in jararhagin disintegrin-like domain the RGD tripeptide is substituted by the ECD sequence and it is expressed in combination to a cysteine-rich domain that contains check details a hyper-variable region (HVR) described in VAP-I crystal structure (Takeda et al., 2006). The disintegrin-like and the cysteine rich domains are not present in MMPs AZD2014 but share high similarity with the analogous domains found in ADAMs (Paine et al., 1992). Crystals of jararhagin have already been described (Souza et al., 2001). Diffraction data has been obtained at a resolution of 2.8 Å showing an asymmetric unit containing two jararhagin molecules. However, when crystal structure was completely solved,
it showed the distinct N-terminal residues corresponding to bothropasin, an isoform with 95.5% identity to jararhagin (Muniz et al., 2008). The crystal structure of bothropasin complexed with the inhibitor POL647 showed the major features already described for VAP-I (Igarashi et al., 2007; Takeda et al., 2006): The catalytic domain is consisted of two sub-domains including the zinc and
calcium-binding sites. The disintegrin domain protrudes from the catalytic domain opposing the catalytic site and is consisted of Ds and Da sub-domains in a C-shaped arm, with no identifiable secondary structure, but loops stabilized by disulfide bonds and by two calcium ions. The cysteine-rich Florfenicol domain includes the HVR described for other P-III SVMPs besides a well-conserved sequence to other P-III members, referred to as PIII-HCR, a highly conserved region (Muniz et al., 2008). The high concentration on the venom and the easy purification protocol allowed extensive studies of jararhagin impact on pathophysiology of B. jararaca envenoming demonstrating its involvement in systemic symptoms and local damaging effects of the venom. As shown in Table 1, jararhagin displays direct action on blood vessel endothelium and sub-endothelial matrix proteins, platelets, coagulation factors as von Willebrand Factor (vWF) and fibrinogen, cell-surface receptors and other cell systems as fibroblasts, epithelial, inflammatory and cancer cells ( Laing & Moura-da-Silva, 2005). Thus, jararhagin is widely used as a model of class P-III SVMPs in studies of mechanisms involved in the action of these toxins and also for clinical investigations into the treatment of envenomings by viper snakes.