Interfacial binding of bee venom secreted phospholipase A2 to membranes occurs predominantly by a nonelectrostatic mechanism

The equilibrium constants for the interaction of wild-type bvPLA2, the charge-reversal mutant (bvPLA2-E5), and the mutant in which the five basic residues were changed to neutral glutamine (bvPLA2Q5) are measured with phosphatidylcholine vesicles containing various amounts of the anionic phosphatidylserine (PS). BvPLA2-E5 with an anionic membrane-binding surface binds more tightly to vesicles as the mole percent of PS is increased.