Dynamics of Crowded Vesicles: Local and Global Responses to Membrane Composition.
Dynamics of Crowded Vesicles: Local and Global Responses to Membrane Composition.
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DOI：
10.1371/journal.pone.0156963
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Khalid S
中科院分区：
文献类型：
--
作者：
Holdbrook DA;Huber RG;Piggot TJ;Bond PJ;Khalid S
细菌的细胞膜是由不同的脂类和蛋白质的混合物组成的，这使得它本身就是一个复杂的细胞器。完整膜蛋白和脂类之间的相互作用对它们在细菌细胞内各自的空间定位是至关重要的。我们使用了微秒时间尺度的粗粒度分子动力学模拟不同大小和不同蛋白质和脂肪组成的囊泡，并使用新的方法来测量局部和全局系统动力学，后者基于球谐分析。我们的结果表明，由于不同的波动模式，嵌入的膜蛋白增强的疏水失配和基于曲率的分选都可能驱动囊泡系统中的组装。有趣的是，小泡的波动模式被发现被小泡的特定蛋白质和脂肪组成所改变。引人注目的是，脂类动力学显示与蛋白质表面的偶联距离长达6 nm，这比以前观察到的距离要大得多，导致了富含特定类型磷脂的多层环状结构。这种大的蛋白质-脂质复合体可能为远程通讯提供了一种机制。考虑到细菌膜的复杂性，我们的结果表明，在基于曲率的膜分选模型下，脂类组成的细微变化可能对脂类和蛋白质分选有重大影响。
The bacterial cell envelope is composed of a mixture of different lipids and proteins, making it an inherently complex organelle. The interactions between integral membrane proteins and lipids are crucial for their respective spatial localization within bacterial cells. We have employed microsecond timescale coarse-grained molecular dynamics simulations of vesicles of varying sizes and with a range of protein and lipid compositions, and used novel approaches to measure both local and global system dynamics, the latter based on spherical harmonics analysis. Our results suggest that both hydrophobic mismatch, enhanced by embedded membrane proteins, and curvature based sorting, due to different modes of undulation, may drive assembly in vesicular systems. Interestingly, the modes of undulation of the vesicles were found to be altered by the specific protein and lipid composition of the vesicle. Strikingly, lipid dynamics were shown to be coupled to proteins up to 6 nm from their surface, a substantially larger distance than has previously been observed, resulting in multi-layered annular rings enriched with particular types of phospholipid. Such large protein-lipid complexes may provide a mechanism for long-range communication. Given the complexity of bacterial membranes, our results suggest that subtle changes in lipid composition may have major implications for lipid and protein sorting under a curvature-based membrane-sorting model.