Ursell Tristan, Huang Kerwyn Casey, Peterson Eric, Phillips Rob
Department of Applied Physics, California Institute of Technology, Pasadena, California, United States of America.
PLoS Comput Biol. 2007 May;3(5):e81. doi: 10.1371/journal.pcbi.0030081.
Biological membranes are elastic media in which the presence of a transmembrane protein leads to local bilayer deformation. The energetics of deformation allow two membrane proteins in close proximity to influence each other's equilibrium conformation via their local deformations, and spatially organize the proteins based on their geometry. We use the mechanosensitive channel of large conductance (MscL) as a case study to examine the implications of bilayer-mediated elastic interactions on protein conformational statistics and clustering. The deformations around MscL cost energy on the order of 10 kBT and extend approximately 3 nm from the protein edge, as such elastic forces induce cooperative gating, and we propose experiments to measure these effects. Additionally, since elastic interactions are coupled to protein conformation, we find that conformational changes can severely alter the average separation between two proteins. This has important implications for how conformational changes organize membrane proteins into functional groups within membranes.
生物膜是弹性介质，其中跨膜蛋白的存在会导致局部双层膜变形。变形能使两个紧密相邻的膜蛋白通过局部变形相互影响彼此的平衡构象，并根据其几何形状在空间上组织这些蛋白。我们以大电导机械敏感通道（MscL）为例，研究双层介导的弹性相互作用对蛋白质构象统计和聚集的影响。MscL周围的变形消耗的能量约为10 kBT，从蛋白质边缘延伸约3 nm，因此弹性力会诱导协同门控，我们提出了测量这些效应的实验。此外，由于弹性相互作用与蛋白质构象相关联，我们发现构象变化会严重改变两个蛋白质之间的平均间距。这对于构象变化如何将膜蛋白组织成膜内的功能基团具有重要意义。
