Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan.
Phys Rev E. 2017 May;95(5-1):052407. doi: 10.1103/PhysRevE.95.052407. Epub 2017 May 16.
We discuss the hydrodynamic collective effects due to active protein molecules that are immersed in lipid bilayer membranes and modeled as stochastic force dipoles. We specifically take into account the presence of the bulk solvent that surrounds the two-dimensional fluid membrane. Two membrane geometries are considered: the free membrane case and the confined membrane case. Using the generalized membrane mobility tensors, we estimate the active diffusion coefficient and the drift velocity as a function of the size of a diffusing object. The hydrodynamic screening lengths distinguish the two asymptotic regimes of these quantities. Furthermore, the competition between the thermal and nonthermal contributions in the total diffusion coefficient is characterized by two length scales corresponding to the two membrane geometries. These characteristic lengths describe the crossover between different asymptotic behaviors when they are larger than the hydrodynamic screening lengths.
我们讨论了由于活跃的蛋白质分子在脂质双层膜中浸入并被建模为随机力偶而产生的流体集体效应。我们特别考虑了包围二维流体膜的主体溶剂的存在。我们考虑了两种膜几何形状：自由膜情况和受限膜情况。使用广义膜迁移率张量，我们估计了扩散物体的扩散系数和漂移速度作为其大小的函数。流体动力学屏蔽长度区分了这些量的两个渐近区域。此外，总扩散系数中的热和非热贡献之间的竞争由与两种膜几何形状对应的两个长度尺度来描述。当这些特征长度大于流体动力学屏蔽长度时，它们描述了不同渐近行为之间的交叉。
