Influence of Monovalent Cation Size on Nanodomain Formation in Anionic–Zwitterionic Mixed Bilayers

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• 作者：Sai J. Ganesan ; Hongcheng Xu ; Silvina Matysiak
• 刊名：Journal of Physical Chemistry B
• 出版年：2017
• 出版时间：February 2, 2017
• 年：2017
• 卷：121
• 期：4
• 页码：787-799
• 全文大小：1370K
• ISSN：1520-5207

文摘

Phosphatidylserine (PS) and phosphatidylcholine (PC) are two of the major anionic and zwitterionic phospholipids in mammalian cell membranes. Ion–PS interaction is hypothesized to play a crucial role in a range of biological events including membrane fusion, lipid phase modulation, membrane protein insertion and translocation. In this study, we characterize lipid nanodomain formation in PC/PS mixed bilayers using coarse-grained simulations. We investigate the role of monovalent cation sizes in modulating lipid–ion binding modes and lipid demixing. Our simulations suggest that certain lipid–ion binding modes lead to growth of ion-mediated PS lipid clusters. The existing literature reveals the polymorphism in binding and partitioning patterns in monovalent cations (Na⁺, K⁺, and Li⁺) with anionic lipids. Our work provides a microscopic view on the ion-size-dependent PS lipid packing pattern observed experimentally. A coupled relationship between lipid curvature and asymmetry is observed in highly demixed PC/PS mixed bilayers.