Xie Ping, Dou Shuo-Xing, Wang Peng-Ye
Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
Acta Biochim Biophys Sin (Shanghai). 2006 Oct;38(10):711-24. doi: 10.1111/j.1745-7270.2006.00223.x.
A model for the unidirectional movement of dynein is presented based on the structural observations and biochemical experimental results available. In this model, the binding affinity of dynein for microtubule (MT) is independent of its nucleotide state and the change between strong and weak MT-binding is determined naturally by the variation of relative orientation between the stalk and MT, as the stalk rotates following nucleotide-state transition. Thus the enigmatic communication from the adenosine triphosphate (ATP)-binding site in the globular domain to the far MT-binding site in the tip of the stalk, which is a prerequisite in conventional models, is not required. Using the present model, the previous experimental results such as the effect of ATP and adenosine diphosphate (ADP) bindings on dissociation of dynein from MT, the movement of single-headed axonemal dyneins at saturating ATP concentration, the load dependence of step-size for the movement of two-headed cytoplasmic dyneins and the dependence of stall force on ATP concentration can be well explained.
基于现有的结构观察和生化实验结果，提出了一种动力蛋白单向运动的模型。在该模型中，动力蛋白与微管（MT）的结合亲和力与其核苷酸状态无关，并且当柄随着核苷酸状态转变而旋转时，强MT结合和弱MT结合之间的变化自然地由柄与MT之间相对取向的变化决定。因此，传统模型中作为前提条件的从球状结构域中的三磷酸腺苷（ATP）结合位点到柄末端远处的MT结合位点之间神秘的信号传递是不需要的。使用当前模型，可以很好地解释先前的实验结果，如ATP和二磷酸腺苷（ADP）结合对动力蛋白从MT上解离的影响、在饱和ATP浓度下单头轴丝动力蛋白的运动、双头胞质动力蛋白运动步长的负载依赖性以及失速力对ATP浓度的依赖性。
