Molecular mechanism of Ca2 +-catalyzed fusion of phospholipid micelles

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/100717

Title:	Molecular mechanism of Ca2 +-catalyzed fusion of phospholipid micelles
Authors:	蔡惠旭;Tsai, Hui-Hsu Gavin;Juang, Wei-Fu;Chang, Che-Ming;Hou, Tsai-Yi;Lee, Jian-Bin
Contributors:	理學院化學學系
Keywords:	Ca2 + -lipid cluster;Free energy landscape;Fusion mechanism;Membrane fusion;Pre-stalk state;Stalk state
Date:	2013-09-03
Issue Date:	2026-04-21 14:11:41 (UTC+8)
Publisher:	Elsevier;Elsevier B.V
Abstract:	摘要： Although membrane fusion plays key roles in intracellular trafficking, neurotransmitter release, and viral infection, its underlying molecular mechanism and its energy landscape are not well understood. In this study, we employed all-atom molecular dynamics simulations to investigate the fusion mechanism, catalyzed by Ca2+ ions, of two highly hydrated 1-palmitoyl-2-oleoyl-sn-3-phosphoethanolamine (POPE) micelles. This simulation system mimics the small contact zone between two large vesicles at which the fusion is initiated. Our simulations revealed that Ca2+ ions are capable of catalyzing the fusion of POPE micelles; in contrast, we did not observe close contact of the two micelles in the presence of only Na+ or Mg2+ ions. Determining the free energy landscape of fusion allowed us to characterize the underlying molecular mechanism. The Ca2+ ions play a key role in catalyzing the micelle fusion in three aspects: creating a more-hydrophobic surface on the micelles, binding two micelles together, and enhancing the formation of the pre-stalk state. In contrast, Na+ or Mg2+ ions have relatively limited effects. Effective fusion proceeds through sequential formation of pre-stalk, stalk, hemifused-like, and fused states. The pre-stalk state is the state featuring lipid tails exposed to the inter-micellar space; its formation is the rate-limiting step. The stalk state is the state where a localized hydrophobic core is formed connecting two micelles; its formation occurs in conjunction with water expulsion from the inter-micellar space. This study provides insight into the molecular mechanism of fusion from the points of view of energetics, structure, and dynamics. [Display omitted] •We determine the molecular mechanism of POPE micelle fusion catalyzed by Ca2+.•Formation of inter-micelle Ca2+-lipid clusters catalyzes the fusion.•Formation of the pre-stalk state with exposed lipid tails is the rate-limiting step.•Effective fusion is initiated by the formation of the pre-stalk state.•Stalk state is formed in conjunction with inter-micellar water expulsion. 出版者： Elsevier B.V 出版日期： 2013-11 出處： Biochimica et biophysica acta. Biomembranes, 2013-11, Vol.1828 (11), p.2729-2738 資源來源： Elsevier ScienceDirect Journals Complete 版權： 2013 Elsevier B.V. 識別號： ISSN: 0005-2736 識別號： EISSN: 1879-2642 識別號： DOI: 10.1016/j.bbamem.2013.07.022
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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