Makarov Dmitrii E, Hofmann Hagen
Department of Chemistry and Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, United States.
Department of Chemical and Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel.
J Phys Chem B. 2021 Jun 17;125(23):6144-6153. doi: 10.1021/acs.jpcb.1c02783. Epub 2021 Jun 3.
The thermal motion of charged proteins causes randomly fluctuating electric fields inside cells. According to the fluctuation-dissipation theorem, there is an additional friction force associated with such fluctuations. However, the impact of these fluctuations on the diffusion and dynamics of proteins in the cytoplasm is unclear. Here, we provide an order-of-magnitude estimate of this effect by treating electric field fluctuations within a generalized Langevin equation model with a time-dependent friction memory kernel. We find that electric friction is generally negligible compared to solvent friction. However, a significant slowdown of protein diffusion and dynamics is expected for biomolecules with high net charges such as intrinsically disordered proteins and RNA. The results show that direct contacts between biomolecules in a cell are not necessarily required to alter their dynamics.
带电蛋白质的热运动在细胞内产生随机波动的电场。根据涨落耗散定理，与这种波动相关存在额外的摩擦力。然而，这些波动对细胞质中蛋白质扩散和动力学的影响尚不清楚。在这里，我们通过在具有时间依赖摩擦记忆核的广义朗之万方程模型中处理电场波动，对这种效应进行了一个数量级的估计。我们发现，与溶剂摩擦相比，电摩擦通常可以忽略不计。然而，对于具有高净电荷的生物分子，如内在无序蛋白质和RNA，预计蛋白质扩散和动力学将显著减慢。结果表明，细胞中生物分子之间不一定需要直接接触就能改变它们的动力学。
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