Use of snake venom inhibitors in studies of the function and tertiary structure of coagulation factors.

C-type lectin-like proteins (CLPs) of snake venom have a variety of biological properties, acting for example as anticoagulants, procoagulants, and agonists/antagonists of platelet activation. The structural and functional studies of the first identified venom CLP, factors IX/X-binding protein (IX/X-bp), have contributed to our understanding of the roles of magnesium ions in the blood coagulation cascade reaction. The crystal structures of gamma-carboxyglutamic acid (Gla) domains of cpagulation factors X and IX have recently been clarified in structural studies of complexes between the Gla domain of factor X and X-bp (a venom CLP) and between the Gla domain of factor IX and IX-bp (a venom CLP).