Association of Lasioglossin-III Antimicrobial Peptide with Model Lipid Bilayers

Abstract: Lasioglossin-III (LL-III) is a small cationic peptide identified in the venom of the Lasioglossum laticeps and is reported to have a potent antimicrobial property with low hemolytic activity. Presently, we explore the nature of interactions and permeability of LL-III peptide in different orientations to lipid bilayers using molecular dynamics (MD) simulations. We performed MD simulations of LL-III peptide at the surface and interior of the pure DMPC and POPC bilayers to determine the membrane-peptide interactions and their effects. LL-III peptide was found to interact with both the lipid bilayers at different rates and showed destabilization at the membrane/water interface with respect to starting state of the peptide. These results suggest the specific interactions between the lysine residues of the peptide with the lipid head group regions, responsible for the overall stability of the peptide in the lipid bilayers. In addition, the results indicate a consistently higher tilt and binding free energy with a decrease in bilayer thickness of DMPC bilayers than in the POPC bilayers due to the peptide insertion.