The venom of the Australian brown snake Pseudonaja textilis contains a prothrombinase-like initiator of blood coagulation, which has evolved into a potent weapon through several gainof-function... Show moreThe venom of the Australian brown snake Pseudonaja textilis contains a prothrombinase-like initiator of blood coagulation, which has evolved into a potent weapon through several gainof-function adaptations. Here we examined the functional implications of a disulfide bond exclusively found in the factor (F)Va-like cofactor component, ptFV. We found that this remarkable structural feature is not required for the procoagulant properties of ptFV. The nearly identical liver-derived plasma ptFV that lacks this disulfide link displayed a similar procoagulant profile. Whether the unique disulfide bond imposes conformational constraints essential to other aspects of the venom FV life cycle remains to be determined. Show less
