Chen Y d
Mathematical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-2690 USA.
Biophys J. 2000 Jan;78(1):313-21. doi: 10.1016/S0006-3495(00)76594-5.
The directional movement on a microtubule of a plastic bead connected elastically to a single one-headed kinesin motor is studied theoretically. The kinesin motor can bind and unbind to periodic binding sites on the microtubule and undergo conformational changes while catalyzing the hydrolysis of ATP. An analytic formalism relating the dynamics of the bead and the ATP hydrolysis cycle of the motor is derived so that the calculation of the average velocity of the bead can be easily carried out. The formalism was applied to a simple three-state biochemical model to investigate how the velocity of the bead movement is affected by the external load, the diffusion coefficient of the bead, and the stiffness of the elastic element connecting the bead and the motor. The bead velocity was found to be critically dependent on the diffusion coefficient of the bead and the stiffness of the elastic element. A linear force-velocity relation was found for the model no matter whether the bead velocity was modulated by the diffusion coefficient of the bead or by the externally applied load. The formalism should be useful in modeling the mechanisms of chemimechanical coupling in kinesin motors based on in vitro motility data.
从理论上研究了与单个单头驱动蛋白马达弹性连接的塑料珠在微管上的定向运动。驱动蛋白马达能够与微管上的周期性结合位点结合和解离，并在催化ATP水解时发生构象变化。推导了一种将珠子动力学与马达ATP水解循环相关联的解析形式，以便能够轻松计算珠子的平均速度。该形式被应用于一个简单的三态生化模型，以研究珠子运动速度如何受到外部负载、珠子的扩散系数以及连接珠子与马达的弹性元件的刚度的影响。发现珠子速度严重依赖于珠子的扩散系数和弹性元件的刚度。无论珠子速度是由珠子的扩散系数还是由外部施加的负载调节，该模型都呈现出线性的力 - 速度关系。这种形式对于基于体外运动数据建立驱动蛋白马达中的化学机械偶联机制模型应该是有用的。
