title: Effect of polyelectrolyte adsorption on lateral distribution and dynamics of anionic lipids: a Monte Carlo study of a coarse-grain model.
abstract: We employ Monte Carlo simulations to investigate the interaction between an adsorbing linear flexible cationic polyelectrolyte and a ternary mixed fluid membrane containing neutral (phosphatidylcholine, PC), monovalent (phosphatidylserine, PS), and multivalent (phosphatidylinositol, PIP2) anionic lipids. We systematically explore the influences of polyelectrolyte chain length, polyelectrolyte charge density, polyelectrolyte total charge amount, and salt solution ionic strength on the static and dynamic properties of different anionic lipid species. Our results show that the multivalent PIP2 lipids dominate the polyelectrolyte-membrane interaction and competitively inhibit polyelectrolyte-PS binding. When the total charge amount of the polyelectrolyte is less than that of the local oppositely charged PIP2 lipids, the polyelectrolyte can drag the bound multivalent lipids to diffuse on the membrane, but cannot interact with the PS lipids. Under this condition, the diffusion behaviors of the polyelectrolyte closely follow the prediction of the Rouse model, and the polyelectrolyte chain properties determine the adsorption amount, concentration gradients, and hierarchical mobility of the bound PIP2 lipids. However, when the total charge amount of the polyelectrolyte is larger than that of the local PIP2 lipids, the polyelectrolyte further binds the PS lipids around the polyelectrolyte-PIP2 complex to achieve local electrical neutrality. In this condition, parts of the polyelectrolyte desorb from the membrane and show faster mobility, and the bound PS presents much faster mobility than the segregated PIP2. This work provides an explanation for heterogeneity formation in different anionic lipids induced by polyelectrolyte adsorption.
authors: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, People's Republic of China.
authors: Xiaozheng
authors: X
authors: Duan
authors: Ran
authors: R
authors: Zhang
authors: Yunqi
authors: Y
authors: Li
authors: Yongbiao
authors: Y
authors: Yang
authors: Tongfei
authors: T
authors: Shi
authors: Lijia
authors: L
authors: An
authors: Qingrong
authors: Q
authors: Huang
mesh_terms: D000327:Adsorption; D004058:Diffusion; D020404:Glycerophospholipids / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D009010:Monte Carlo Method
chemical_list: D020404:Glycerophospholipids