Structural highlights
FunctionSLEA_BOTJA Snaclec that binds to von Willebrand factor (VWF) and induces its interaction with GPIbalpha (GP1BA) (via the vWF A1 domain), resulting in platelet aggregation. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBotrocetin is a snake venom protein that enhances the affinity of the A1 domain of plasma von Willebrand factor (vWF) for the platelet receptor glycoprotein Ibalpha (GPIbalpha), an event that contributes to bleeding and host death. Here we describe a kinetic and crystallographic analysis of this interaction that reveals a novel mechanism of affinity enhancement. Using high-temporal-resolution microscopy, we show that botrocetin decreases the GPIbalpha off-rate two-fold in both human and mouse complexes without affecting the on-rate. The key to this behavior is that, upon binding of GPIbalpha to vWF-A1, botrocetin prebound to vWF-A1 makes no contacts initially with GPIbalpha, but subsequently slides around the A1 surface to form a new interface. This two-step mechanism and flexible coupling may prevent adverse alterations in on-rate of GPIbalpha for vWF-A1, and permit adaptation to structural differences in GPIbalpha and vWF in several prey species. The snake venom protein botrocetin acts as a biological brace to promote dysfunctional platelet aggregation.,Fukuda K, Doggett T, Laurenzi IJ, Liddington RC, Diacovo TG Nat Struct Mol Biol. 2005 Feb;12(2):152-9. Epub 2005 Jan 16. PMID:15665869[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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