Purification and Characterization of Bitiscetin, a Novel von Willebrand Factor Modulator Protein fromBitis arietansSnake Venom

Crystal Structure of von Willebrand Factor A1 Domain Complexed with Snake Venom, Bitiscetin

“…Materials-Bitiscetin was purified from crude venom of Bitis arietans (purchased from ICN Biomedicals Inc.) as described previously (8). Recombinant VWF A1 domain (residues 497-708), expressed in Escherichia coli and purified as described (24), was further purified with MonoQ (Amersham Biosciences) and TSK-GEL G2000SW gel filtration column (Tosoh).…”

“…A structural change in the Asp 560 -Gly 561 region was observed in the structure of the VWD type 2B "gain-of-function" A1 domain mutant, which binds spontaneously to GPIb under physiological conditions (6). Binding of VWF to platelets in vitro occurs in the presence of various modulators, such as the antibiotic ristocetin (7) or snake venom proteins bitiscetin (8) or botrocetin (9). Snakes employ bitiscetin and botrocetin to disrupt hemostasis and thereby to kill or weaken their prey; these modulators have been used extensively as tools to study the complicated mechanisms involved in hemostasis.…”

The Collagen-binding Integrin α2β1 Is a Novel Interaction Partner of the Trimeresurus flavoviridis Venom Protein Flavocetin-A

“…GPIb is a receptor for the plasma glycoprotein vWF, which initiates platelet adhesion to exposed vascular subendothelium, consequently activating platelets and leading to hemostasis (10,11). Many CLRPs block the vWF-binding site on the GPIb receptor; however, others enhance the interaction of GPIb and vWF (12)(13)(14)(15).…”

Multifunctional Snake C-Type Lectins Affecting Platelets

“…Bitiscetin from Bitis arietans venom [26] forms a bimolecular complex with vWF, like botrocetin; however the binding site of bitiscetin is within the A3 domain [27]. Binding also involves the GPIb-binding site of vWF located on the A1 domain because it was inhibited by a monoclonal antibody to vWF whose epitopes are within this domain and that block binding of vWF to platelets induced by ristocetin or botrocetin.…”