Simulating the insertion dynamics of an anionic model protein into a cationic triblock copolymer membrane

Experiments suggest that the reconstitution of anionic proteins into synthetic, cationic triblock copolymer membranes proceeds spontaneously through a charge-mediated mechanism. This mechanism is yet to be elucidated. We recently developed a dynamical self-consistent field theory for the self-assembly of charged polymers in an electrolyte solution. Here, we use this theory to examine the dynamical process whereby an anionic model protein, which we model as a triblock copolymer with charged solvophillic end-blocks, inserts into a self-assembled triblock copolymer membrane with cationic solvophillic end-blocks. By tracking the centres of mass of the two end-blocks of the protein we obtain a detailed description of the stages in the process of protein insertion. In particular, by repeated simulation we generate the distribution of insertion times. We examine how this distribution depends on the charge of both the model protein and the membrane. These results enhance our understanding of the mechanism for charge-mediated protein reconstitution.