title: Coarse-grained molecular dynamics simulation of binary charged lipid membranes: Phase separation and morphological dynamics.
abstract: Biomembranes, which are mainly composed of neutral and charged lipids, exhibit a large variety of functional structures and dynamics. Here, we report a coarse-grained molecular dynamics (MD) simulation of the phase separation and morphological dynamics in charged lipid bilayer vesicles. The screened long-range electrostatic repulsion among charged head groups delays or inhibits the lateral phase separation in charged vesicles compared with neutral vesicles, suggesting the transition of the phase-separation mechanism from spinodal decomposition to nucleation or homogeneous dispersion. Moreover, the electrostatic repulsion causes morphological changes, such as pore formation, and further transformations into disk, string, and bicelle structures, which are spatiotemporally coupled to the lateral segregation of charged lipids. Based on our coarse-grained MD simulation, we propose a plausible mechanism of pore formation at the molecular level. The pore formation in a charged-lipid-rich domain is initiated by the prior disturbance of the local molecular orientation in the domain.
authors.affiliation: Department of Mechanical Engineering, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ito
authors.affiliation: Institute for Materials Research, Tohoku University, Miyagi 980-8577, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: School of Materials Science, Japan Advanced Institute of Science and Technology, Ishikawa 923-1292, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Shimokawa
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D055672:Static Electricity
chemical_list: D008051:Lipid Bilayers