DIFFUSION OF PIP2 IN LIPID MEMBRANE INFLUENCED BY ADSORBED POLYELECTROLYTES
The influence of adsorbed DNA, protein and other biomacromolecules on the fluidity of membranes greatly correlates to the biologic activities. Research on the lipid layer, which can respond to interactions with polyelectrolytes constituting the central structural element of biological membranes, is one of the main paths to explore this physiological process. In past decades, interaction between polyelectrolytes and many charged lipid species such as PEP_2(phosphatidylinositol 4,5 bisphosphate) and PS(phosphatidyl-choline), has been performing a vital role in factors resulting in phase characteristics of the domains and formation of lipid rafts. The complexation between an adsorbed flexible linear cationic polelectrolyte and an fluid membranes containing neutral lipids and multivalent anionic lipids (PIP2) is investigated by means of Monte Carlo simulations. Attention is focused on the effect of ionic concentration, chain length and charge of monomer of polyelectrolytes on (i) the slaved PIP_2 number in areas around adsorbed polyelectrolytes, (Ⅱ) diffusion of PIP_2 in areas affected by the adsorbed polyelectrolytes, (iii) adsorbing time of PIP2 in areas affected by the adsorbed polyelectrolytes. The extent of charged lipids adsoption around the polyelectrolytes and their corresponding diffusion behaviors are found to be the result of several competing effects: the electrostatic repulsion between the chain monomers which forces the polyelectrolyte to adopt extended conformations onto the membrane, the electrostatic attractive interactions between the different charged lipids and the monomers and the electrostatic repulsion between the charged lipids forcing the chain and two lipid species to undergo a structural transition. To overcome the loss of entropy per monomer and lipid due to adsorption, it is shown that a stronger electrostatic attraction, with decreasing ionic concentration, is needed for the short chains. Below that critical ionic concentration, it is found that the degree of adsorption of the charged lipids slaved by the polyelectrolyte increases with the decrease in ionic strength and increase in both the chain length and the charge of monomer of polyelectrolytes. Confined diffusion behaviors of the charged lipids turn more notable with the increasing of adsorption. As chain length and charge of monomer are increased further, a dramatic increasing fluidity of charged lipides occurs in accordance with a larger occluded area of adsorbate.
Xiaozheng Duan Tongfei Shi Lijia An
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022
国际会议
PP’2010，Jinan International Symposium on Polymer Physics(2010济南国际高分子物理学术研讨会)
济南
英文
435-436
2010-06-06（万方平台首次上网日期，不代表论文的发表时间）