Surface Shear Viscosity and Interleaflet Friction from Nonequilibrium Simulations of Lipid Bilayers.
Surface Shear Viscosity and Interleaflet Friction from Nonequilibrium Simulations of Lipid Bilayers.
复制标题
脂质双层非平衡模拟的表面剪切粘度和叶间摩擦。
DOI：
10.1021/acs.jctc.9b00683
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发表时间：
2019
影响因子：
5.5
通讯作者：
Lyman,Edward
中科院分区：
文献类型：
--
作者：
Zgorski,Andrew;Pastor,RichardW;Lyman,Edward
基于剪切变形的非平衡模拟协议被应用于确定脂质双层的表面粘度和叶间摩擦。在高剪切速率下，观察到非牛顿剪切稀化制度，但较低的剪切速率产生牛顿平台和与基于波动耗散定理的平衡测量一致的结果。应用程序与CHARMM 36参数集建模的全原子双层产生的表面粘度值是一致的，基于膜蛋白扩散的微观测量，但比更宏观的实验测量低约10倍。瓣叶间摩擦比实验测量值低约10倍。在不同的脂质，温度和三元液体无序相混合物的趋势产生的结果是一致的实验扩散常数。将该方案应用于液体有序相未能产生牛顿平台，这表明流变学更复杂。
Nonequilibrium simulation protocols based on shear deformations are applied to determine the surface viscosity and interleaflet friction of lipid bilayers. At high shear rates, a non-Newtonian shear thinning regime is observed, but lower shear rates yield a Newtonian plateau and results that are consistent with equilibrium measurements based on fluctuation-dissipation theorems. Application to all-atom bilayers modeled with the CHARMM36 parameter set yields values for the surface viscosity that are consistent with microscopic measurements based on membrane protein diffusion but are approximately 10 times lower than more macroscopic experimental measurements. The interleaflet friction is about 10 times lower than experimental measurements. Trends across different lipids, temperatures, and ternary liquid-disordered phase mixtures produce results that are consistent with experimental diffusion constants. Application of the protocol to the liquid-ordered phase fails to yield a Newtonian plateau, suggesting more complex rheology.