Diffusing proteins on a fluctuating membrane: analytical theory and simulations.
Diffusing proteins on a fluctuating membrane: analytical theory and simulations.
复制标题
在波动膜上扩散蛋白质：分析理论和模拟。
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
U. Seifert
中科院分区：
文献类型：
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作者：
Ellen Reister;Stefan M Leitenberger;U. Seifert
使用解析计算和计算机模拟，我们考虑的横向扩散的膜蛋白质和蛋白质嵌入的膜的波动谱。膜蛋白通过其自发曲率和弯曲刚度与膜形状相互作用。蛋白质的横向运动可以被看作是在有效电势下的扩散，因此，与自由扩散的情况相比，有效迁移率总是降低的。使用严格的路径积分的方法，我们推导出一个解析表达式的有效扩散系数的温度和弯曲刚度的小比例，这是生物学相关的限制。模拟结果与我们的分析结果有很好的定量一致性。对扩散系数的相关函数的分析表明，蛋白质的随机力和膜形状的响应之间的相关性是减少的原因。我们的膜高度相关光谱的定量分析表明，蛋白质-膜相互作用的影响，造成一个明显改变的波矢量依赖相比，一个自由的膜。此外，时间相关性表现出两个相关的时间尺度的系统：膜波动和横向蛋白质扩散，后者通常比前者长得多。我们认为，膜高度相关性的长时间衰减的分析，从而可以提供一种新的手段来确定膜中的蛋白质的有效扩散系数。
Using analytical calculations and computer simulations, we consider both the lateral diffusion of a membrane protein and the fluctuation spectrum of the membrane in which the protein is embedded. The membrane protein interacts with the membrane shape through its spontaneous curvature and bending rigidity. The lateral motion of the protein may be viewed as diffusion in an effective potential, hence, the effective mobility is always reduced compared to the case of free diffusion. Using a rigorous path-integral approach, we derive an analytical expression for the effective diffusion coefficient for small ratios of temperature and bending rigidity, which is the biologically relevant limit. Simulations show very good quantitative agreement with our analytical result. The analysis of the correlation functions contributing to the diffusion coefficient shows that the correlations between the stochastic force of the protein and the response in the membrane shape are responsible for the reduction. Our quantitative analysis of the membrane height correlation spectrum shows an influence of the protein-membrane interaction causing a distinctly altered wave-vector dependence compared to a free membrane. Furthermore, the time correlations exhibit the two relevant time scales of the system: that of membrane fluctuations and that of lateral protein diffusion with the latter typically much longer than the former. We argue that the analysis of the long-time decay of membrane height correlations can thus provide a new means to determine the effective diffusion coefficient of proteins in the membrane.