Lipid bilayer pressure profiles and mechanosensitive channel gating
Lipid bilayer pressure profiles and mechanosensitive channel gating
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DOI：
10.1529/biophysj.103.034322
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发表时间：
2004-06-01
影响因子：
3.4
通讯作者：
Schulten, K
中科院分区：
文献类型：
--
作者：
Gullingsrud, J;Schulten, K
膜蛋白的功能通常取决于蛋白质与其脂质环境的相互作用，特别是在机械敏感通道的情况下，其通过周围脂质介导的张力门控。脂质双层张力分布很不均匀，但无论是规模的相关变化发生，也没有改变脂质成分或张力的影响尚未在原子细节的研究。我们计算了横向压力分布在各种组合物的脂质双层从全原子分子动力学模拟总计110.5纳秒的长度。确定了在1 A长度尺度下的可再现压力分布特征。与磷脂酰胆碱头基的脂质被发现转移的疏水核心的侧压力，并进入头基区域的量是独立的面积每脂质。在小于最佳的区域模拟的POPE双层在脂肪链开始处的狭窄区域中施加显著更高的侧向压力。POPC双层的拉伸主要增加了同一区域的紧张局势。一个简单的几何分析的mechanosensitive通道MscL的门控表明，压力分布影响其门控通过第二时刻的轮廓在一个张力独立的方式。
The function of membrane proteins often depends on the proteins' interaction with their lipid environment, spectacularly so in the case of mechanosensitive channels, which are gated through tension mediated by the surrounding lipids. Lipid bilayer tension is distributed quite inhomogeneously, but neither the scale at which relevant variation takes place nor the effect of varying lipid composition or tension has yet been investigated in atomic detail. We calculated lateral pressure profile distributions in lipid bilayers of various composition from all-atom molecular dynamics simulations totaling 110.5 ns in length. Reproducible pressure profile features at the 1 A length scale were determined. Lipids with phosphatidylcholine headgroups were found to shift the lateral pressure out of the hydrophobic core and into the headgroup region by an amount that is independent of area per lipid. POPE bilayers simulated at areas smaller than optimal exerted dramatically higher lateral pressure in a narrow region at the start of the aliphatic chain. Stretching of POPC bilayers increased tension predominantly in the same region. A simple geometric analysis for the gating of the mechanosensitive channel MscL suggests that pressure profiles affect its gating through the second moment of the profile in a tension-independent manner.