The available single-molecule data showed that different species of N-terminal kinesin molecular motors have very different features on dependences of run length and dissociation rate upon longitudinal load acting on stalks of the motors. The prior single-molecule data for Loligo pealei kinesin-1 indicated that the sideways load has only a weak effect on the velocity, but even a small sideways load can cause a large reduction in the run length. However, these puzzling experimental data remain to be explained and the underlying physical mechanisms are unclear. Here, based on our proposed model we study analytically the dynamics of the N-terminal kinesin motors such as Loligo pealei kinesin-1, Drosophila kinesin-1, truncated kinesin-5/Eg5, truncated kinesin-12/Kif15, kinesin-2/Kif17 and kinesin-2/Kif3AB dimers under both longitudinal and sideways loads. The theoretical results explain quantitatively the available experimental data and provide predictions. The physical mechanism of different kinesin species showing very different features on the load-dependent dynamics and the physical mechanism of the effect of the sideways load on the dynamics are revealed.

可用的单分子数据表明，不同种类的 N 末端驱动蛋白分子马达在运行长度和解离速率对作用于马达茎的纵向载荷的依赖性方面具有非常不同的特征。Loligo pealei kinesin-1的先前单分子数据表明，侧向载荷对速度的影响很小，但即使是很小的侧向载荷也会导致运行长度的大幅减少。然而，这些令人费解的实验数据仍有待解释，潜在的物理机制尚不清楚。在这里，基于我们提出的模型，我们分析研究了 N 端驱动蛋白马达的动力学，例如Loligo pealei kinesin-1、果蝇kinesin-1、截短的 kinesin-5/Eg5、截短的 kinesin-12/Kif15、kinesin-2/Kif17 和 kinesin-2/Kif3AB 二聚体在纵向和横向载荷下。理论结果定量地解释了可用的实验数据并提供了预测。揭示了不同驱动蛋白种类在负载相关动力学中表现出非常不同特征的物理机制以及侧向负载对动力学影响的物理机制。