Computational modeling of anionic and zwitterionic lipid bilayers for investigating surface activities of bioactive molecules

Abstract

Phosphatidylgylcerols (PGs) and Phosphatidylethanolamines (PEs) are of considerable interest because they are major lipid components of bacterial membranes and the non-harged PE can also serve as a model for cell membranes of multi-cellular organisms. Here, we report molecular dynamics (MD) simulations studies of the structural and dynamics properties of negatively charged POPG and zwitterionic POPE bilayers. The hydrocarbon chain fluidity and the electron density distribution of various groups along the bilayer were extensively analyzed and compared with the available experimental data. A specific focus was given on hydrogen bond formations and position of sodium ions in the lipid bilayers. These validated and equilibrated models were subsequently employed to investigate selectivity and mechanism of action of the antimicrobial peptide of interest. We found that hydrogen bonding and electrostatic interactions potentially play a role in the adsorption of a peptide to the membrane interface. We observed the peptide's insertion into the membrane can decrease the order parameter and induce local membrane deformation. © 2009 Materials Research Society.