Illustrating Interfacial Interaction between Honey Bee Venom Phospholipase A and Supported Negatively Charged Lipids with Sum Frequency Generation and Laser Scanning Confocal Microscopy.

Phospholipase A is an important enzyme species which can widely be found in animals, plants, bacteria, and so on. A large number of studies have shown that phospholipase A is highly catalytic toward the lipids. Here, sum frequency generation (SFG) vibrational spectroscopy and laser scanning confocal microscopy (LSCM) were applied to study the interaction between honey bee venom phospholipase A (bvPLA) and the negatively charged DPPG bilayer. In both cases without and with the calcium ions (Ca), the bvPLA molecules were adsorbed onto the outer leaflet surface with the orientational order, and the adsorbed bvPLA molecules damaged the order of the packed outer leaflet. In comparison to the case without Ca, the addition of Ca can accelerate the attaching process of bvPLA to the outer leaflet surface and decelerate the process of damaging the outer leaflet order. The experimental result also confirmed, with the help of the Ca, the DPPG molecules in the outer leaflet were hydrolyzed, with both hydrolysates, that is, lysophospholipids and fatty acids, remaining at the interface, showing a distinct difference from previous published literatures regarding neutral lipids [ , , 63-67] and PLA [ , , 12831-12838].