Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
Soft Matter. 2017 May 24;13(20):3741-3749. doi: 10.1039/c7sm00400a.
Experimental studies of systems containing active proteins that undergo conformational changes driven by catalytic chemical reactions have shown that the diffusion coefficients of passive tracer particles and active molecules are larger than the corresponding values when chemical activity is absent. Various mechanisms have been proposed for such behavior, including, among others, force dipole interactions of molecular motors moving on filaments and collective hydrodynamic effects arising from active proteins. Simulations of a multi-component system containing active dumbbell molecules that cycle between open and closed states, a passive tracer particle and solvent molecules are carried out. Consistent with experiments, it is shown that the diffusion coefficients of both passive particles and the dumbbells themselves are enhanced when the dumbbells are active. The dependence of the diffusion enhancement on the volume fraction of dumbbells is determined, and the effects of crowding by active dumbbell molecules are shown to differ from those due to inactive molecules.
含有活性蛋白的系统的实验研究表明，在没有催化化学反应的情况下，被动示踪粒子和活性分子的扩散系数大于相应的值。已经提出了各种机制来解释这种行为，包括分子马达在纤维上的力偶极相互作用和活性蛋白产生的集体流体动力学效应。对含有活性哑铃分子（在开和闭状态之间循环）、一个被动示踪粒子和溶剂分子的多组分系统进行了模拟。与实验一致的是，当哑铃分子处于活跃状态时，被动粒子和哑铃本身的扩散系数都得到了增强。确定了扩散增强对哑铃体积分数的依赖性，并表明活性哑铃分子的拥挤效应与非活性分子的拥挤效应不同。
