Molecular motors are responsible for intracellular transport of a variety of biological cargo. We consider the collective behaviour of a finite number of motors attached on a cargo. We extend previous analytical work on processive motors to the case of non-processive motors, which stochastically bind on and off cytoskeletal filaments with a limited number of binding sites available. Physically, motors attached to a cargo cannot bind anywhere along the filaments, so the number of accessible binding sites on the filament should be limited. Thus, we analytically study the distribution and the velocity of a cluster of non-processive motors with limited number of binding sites. To validate our analytical results and to go beyond the level of detail possible analytically, we perform Monte Carlo latticed based stochastic simulations. In particular, in our simulations, we include sequence preservation of motors performing stepping and binding obeying a simple exclusion process. We find that limiting the number of binding sites reduces the probability of non-processive motors binding but has a relatively small effect on force–velocity relations. Our analytical and stochastic simulation results compare well to published data from in vitro and in vivo experiments.

分子马达负责各种生物货物的细胞内运输。我们考虑有限数量的电动机附着在货物上的集体行为。我们将以前对过程性电机的分析工作扩展到非过程性电机的情况，非过程性电机随机地在细胞骨架丝上和细胞外束缚，并具有有限数量的结合位点。从物理上讲，附着在货物上的电动机无法沿着细丝束缚任何地方，因此应该限制细丝上可及的结合位点的数量。因此，我们分析性地研究了具有有限结合位点的非过程性电机簇的分布和速度。为了验证我们的分析结果并超出可能进行分析的详细程度，我们执行了基于蒙特卡洛网格的随机模拟。尤其是，在我们的仿真中，我们包括遵循简单排除过程执行步进和绑定的电机的序列保存。我们发现限制结合位点的数量会降低非过程性马达结合的可能性，但对力-速度关系的影响相对较小。我们的分析和随机模拟结果与来自体外和体内实验。