title: Spontaneous buckling of lipid bilayer and vesicle budding induced by antimicrobial peptide magainin 2: a coarse-grained simulation study.
abstract: Molecular mechanisms of the action of antimicrobial peptides on bacterial membranes were studied by large scale coarse-grained simulations of magainin 2-dipalmitoylphosphatidylcholine/palmitoyloleoylphosphatidylglycerol (DPPC/POPG) mixed bilayer systems with spatial extents up to 0.1 μm containing up to 1600 peptides. Equilibrium simulations exhibit disordered toroidal pores stabilized by peptides. However, when a layer of peptides is placed near the lipid head groups on one side of the bilayer only, their incorporation leads to a spontaneous buckling of the bilayer. This buckling is followed by the formation of a quasi-spherical vesicular bud connected to the bilayer by a narrow neck. The mean curvature of the budding region is consistent with what is expected based on the dependence of the area per lipid on the peptide-to-lipid ratio in equilibrium simulations. Our simulations suggest that the incorporation of antimicrobial peptides on the exterior surface of a vesicle or a bacterial cell leads to buckling and vesicle budding, presumably accompanied by nucleations of giant transient pores of sizes that are much larger than indicated by equilibrium measurements and simulations.
authors.affiliation: Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, Maryland 21702, United States. woo@bioanalysis.org
authors.forename: Hyung-June
authors.initials: HJ
authors.lastname: Woo
authors.forename: Anders
authors.initials: A
authors.lastname: Wallqvist
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D054806:Magainins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010715:Phosphatidylglycerols / Q000737:chemistry; D029867:Xenopus Proteins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D054806:Magainins; D010715:Phosphatidylglycerols; D029867:Xenopus Proteins; C053301:magainin 2 peptide, Xenopus; D015060:1,2-Dipalmitoylphosphatidylcholine; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol