(376az) Molecular Dynamics Simulation on Interaction of Human Beta Defensin Type 3 with Different Lipid Bilayers

Human beta defensin type 3 (hBD-3) belongs to the human innate immune system. It is a natural antibacterial peptide mainly secreted from the human epithelial cells, and has a charge density of +11. It can interact with bacterial cell membranes which are overall negatively charged and can translocate through the cell membrane. In this project, the interaction and dynamics of hBD-3 in both monomer and dimer forms embedded inside different negatively charged lipid bilayers (to represent bacterial membranes) were investigated using CHARMM and NAMD molecular dynamics simulations. It was found that water molecules can cross the lipid bilayers through hBD-3, with the flow rate dependent on the lipid chemical composition and oligomerization form of hBD-3. Aggregation of negatively charged lipids around hBD-3 was observed based on micro-second long all-atom simulations, although such kind of lipid segregation was not observed in mixed lipid membrane systems only.