Phase Transition in a Heterogeneous Membrane: Atomically Detailed Picture
Phase Transition in a Heterogeneous Membrane: Atomically Detailed Picture
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异质膜中的相变：原子详细图片
DOI：
10.1021/acs.jpclett.0c01255
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Elber, Ron
中科院分区：
文献类型：
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作者：
Fathizadeh, Arman;Valentine, Mason;Baiz, Carlos R.;Elber, Ron
膜在生物系统中具有多种功能。分子组成的变化会影响其物理性质，并导致丰富的相行为，例如从凝胶相切换到流体相和/或分离到具有不同分子组成的微观和宏观结构域。我们提出了1,2-二棕榈酰-sn-甘油-3-磷酸胆碱（DPPC）和1,2-二酰-sn-甘油-3-磷酸胆碱（DLPC）分子混合膜的相行为的计算和实验相结合的研究。这种非均质膜从凝胶变为流体，并随着温度的变化显示出不同的结构域。原子细节模拟提供了这些分子组合的微观信息。然而，这些系统的计算具有挑战性，因为接近平衡需要非常长的分子动力学轨迹。我们使用MDAS （Molecular Dynamics with Alchemical Steps）的模拟方法来生成足够的统计数据。使用同位素编辑的脂质红外光谱作为模拟的基准。同时，模拟和实验提供了洞察相图的结构和动力学特征。
Membranes serve diverse functions in biological systems. Variations in their molecular compositions impact their physical properties and lead to rich phase behavior such as switching from the gel to fluid phase and/or separation to micro- and macrodomains with different molecular compositions. We present a combined computational and experimental study of the phase behavior of a mixed membrane of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) molecules. This heterogeneous membrane changes from gel to fluid and shows separate domains as a function of temperature. Atomically detailed simulations provide microscopic information about these molecular assemblies. However, these systems are challenging for computations since approaching equilibrium necessitates exceptionally long molecular dynamics trajectories. We use the simulation method of MDAS (Molecular Dynamics with Alchemical Steps) to generate adequate statistics. Isotope-edited IR spectroscopy of the lipids was used to benchmark the simulations. Together, simulations and experiments provide insight into the structural and dynamical features of the phase diagram.