Close-up View of the Modifications of Fluid Membranes Due to Phospholipase A(2)

Phospholipases are a class of molecular machines that are involved in the active remodelling processes of biological membranes. These lipases are interfacially activated enzymes and in the specific case of phospholipase A(2) (PLA(2)) the enzyme catalyses the hydrolysis of di-acyl phospholipids into products of lysolipids and fatty acids, that dramatically change the physical properties of lipid membrane substrates. Using dissipative particle dynamics simulations on a simple coarse-grained bead-spring model of a fluid lipid bilayer in water, the mechanical and diffusive properties of the bilayer in the pure state and after the action of PLA(2) have been calculated. It is found that, in response to hydrolysis, the lipid membrane becomes mechanically softened and the various in-plane and trans-bilayer diffusional modes become enhanced. The results compare favourably with available experimental data.