Curvature Energetics Determined by Alchemical Simulation on Four Topologically Distinct Lipid Phases.
Curvature Energetics Determined by Alchemical Simulation on Four Topologically Distinct Lipid Phases.
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DOI：
10.1021/acs.jpcb.0c09458
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发表时间：
2021-02-25
影响因子：
3.3
通讯作者：
Sodt, Alexander J.
中科院分区：
文献类型：
--
作者：
Beaven, Andrew H.;Arnarez, Clement;Lyman, Edward;Bennett, W. F. Drew;Sodt, Alexander J.
两种脂质的相对曲率能量测试使用热力学积分（TI）上的四个拓扑不同的脂质相。模拟使用TI在胆碱头基脂质（POPC;更喜欢扁平的）和乙醇胺头基脂质（POPE;更喜欢例如囊泡的内层单层）之间切换。通过热力学方法在平面、反六边形（HII）、立方（QII; Pn 3 m空间群）和囊泡拓扑结构之间移动脂质，揭示了以前无法获得的材料参数差异。该方法允许预测两个重要的脂质材料性质：POPC/POPE单层固有曲率的差异（Δ J 0）和POPC/POPE单层高斯曲率模量的差异（），两者都与拓扑变化的能量学有关。对TI数据的分析表明，与先前的实验和模拟一致，POPE的J 0比POPC的更负（Δ J 0 = −0.018 ± 0.001 Ω −1）。理论框架提取的显着差异，其中，POPE是少负比POPC的2.0至4.0千卡/摩尔。这些值的范围是通过考虑模拟的子集来确定的，并且这些子集之间的不一致表明在非常高的曲率下的单独的机械参数。最后，TI数据与模型的拟合表明，在高曲率下，枢轴曲率平面的位置在拓扑结构中不是恒定的。总的来说，这些结果提供了对脂质材料特性、单个HC模型的限制以及如何使用模拟来测试它们的见解。
The relative curvature energetics of two lipids are tested using thermodynamic integration (TI) on four topologically distinct lipid phases. Simulations use TI to switch between choline head group lipids (POPC; that prefers to be flat) and ethanolamine head group lipids (POPE; that prefer, for example, the inner monolayer of vesicles). Thermodynamically moving the lipids between planar, inverse hexagonal (HII), cubic (QII; Pn3m space group), and vesicle topologies reveals differences in material parameters that were previously inaccessible. The methodology allows for predictions of two important lipid material properties: the difference in POPC/POPE monolayer intrinsic curvature (ΔJ0) and the difference in POPC/POPE monolayer Gaussian curvature modulus (), both of which are connected to the energetics of topological variation. Analysis of the TI data indicates that, consistent with previous experiment and simulation, the J0 of POPE is more negative than POPC (ΔJ0 = −0.018 ± 0.001 Å−1). The theoretical framework extracts significant differences in , of which, POPE is less negative than POPC by 2.0 to 4.0 kcal/mol. The range of these values is determined by considering subsets of the simulations, and disagreement between these subsets suggests separate mechanical parameters at very high curvature. Finally, the fit of the TI data to the model indicates that the position of the pivotal plane of curvature is not constant across topologies at high curvature. Overall, the results offer insights into lipid material properties, the limits of a single HC model, and how to test them using simulation.
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