肌球蛋白VI分子马达周期势场下的弹性扩散模型

摘要

Because of the special structure and intracellular functions of myosin VI molecular motor, its dynamic principle has become a research focus. Starting from its structure and experimental phenomenon, the elastic-diffusion model of myosin VI in a periodic potential field is established, and the stochastic dynamics of the molecular motors, which conform to the Langevin equation, is analyzed by Monte Carlo simulations. By means of the environmental noise, myosin VI molecular motors could take stable stepping motion and effective transport according to its elastic potential energy and periodic potential of track, and a load can weaken the transportation power of the molecular motor system. For a given elastic coefficient, the longer the elastic chain of myosin VI, the lower the average velocity of it. By selecting a reasonable size of elasticity coefficient, the average velocity can be the maximum for a given elastic chain. In addition, the load can increase exponentially the mean dwelling time of myosin VI at the connection site.%肌球蛋白VI分子马达因其特殊的结构及胞内功能，其动力学原理成为研究的热点。从肌球蛋白VI自身结构和实验现象出发，建立其弹性扩散模型，并通过Monte Carlo方法分析了肌球蛋白VI满足朗之万方程的随机动力学行为。结果表明，在环境噪声作用下，具有弹性势能和轨道周期势能的肌球蛋白VI可以进行梯跳运动和有效的输运，但负载力会减弱分子马达系统的输运能力；当弹性系数一定时，弹性链越长平均速度越小，当弹性链长度一定时，合理选择弹性系数平均速度可达到最大值；另外，负载力的存在使肌球蛋白VI在接触位点的平均驻留时间呈指数增加。