A Quantitative Coarse-Grain Model for Lipid Bilayers

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• 作者：Mario Orsi ; David Y. Haubertin ; Wendy E. Sanderson ; Jonathan W. Essex
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：January 24, 2008
• 年：2008
• 卷：112
• 期：3
• 页码：802 - 815
• 全文大小：588K
• 年卷期：v.112,no.3(January 24, 2008)
• ISSN：1520-5207

文摘

A simplified particle-based computer model for hydrated phospholipid bilayers has been developed and appliedto quantitatively predict the major physical features of fluid-phase biomembranes. Compared with availablecoarse-grain methods, three novel aspects are introduced. First, the main electrostatic features of the systemare incorporated explicitly via charges and dipoles. Second, water is accurately (yet efficiently) described, onan individual level, by the soft sticky dipole model. Third, hydrocarbon tails are modeled using the anisotropicGay-Berne potential. Simulations are conducted by rigid-body molecular dynamics. Our technique proves 2orders of magnitude less demanding of computational resources than traditional atomic-level methodology.Self-assembled bilayers quantitatively reproduce experimental observables such as electron density, compressibility moduli, dipole potential, lipid diffusion, and water permeability. The lateral pressure profile has beencalculated, along with the elastic curvature constants of the Helfrich expression for the membrane bendingenergy; results are consistent with experimental estimates and atomic-level simulation data. Several of theresults presented have been obtained for the first time using a coarse-grain method. Our model is also directlycompatible with atomic-level force fields, allowing mixed systems to be simulated in a multiscale fashion.