Curvature effect and stabilize ruptured membrane of BAX derived peptide studied by molecular dynamics simulations

BAX protein plays a key role in mitochondrial membrane permeabilization and cytochrome c release upon apoptosis. The C-terminal transmembrane domain (TMD) of BAX is supposed to act a membrane anchor when BAX is activated leading to programmed cell death. Previous studies indicate that the C-terminal transmembrane domain of BAX mediates membrane disruption and pore formation, however, the mechanism of the membrane disruption and pore-forming capability of BAX C-terminal transmembrane domain still unclear. Here, we performed all-atom (AA) molecular dynamics simulations to study the membrane effect of TMD peptide. We also conducted coarse-grained (CG) molecular dynamics simulations to study the membrane curvature and the stabilization of ruptured membrane pores effect of TMD peptides. Our results indicated that TMD peptide decreases the local POPC lipids order. The membrane binding of TMD induced a positive membrane curvature, moreover, certain numbers of TMD could stabilize ruptured membrane pore in both CG and AA simulations. These results provide insight into the structure details of membrane pore formation by TMD peptides. The diameters of the pore are qualitatively in good agreement with available experimental data.