The molecular motor myosin undergoes a series of major structural transitions during its force-producing motor cycle. The underlying mechanism and its coupling to ATP hydrolysis and actin binding is only partially understood, mostly due to sparse structural data on actin-bound states of myosin. Here, we report 26 high-resolution cryo-EM structures of the actomyosin-V complex in the strong-ADP, rigor, and a previously unseen post-rigor transition state that binds the ATP analog AppNHp. The structures reveal a high flexibility of myosin in each state and provide valuable insights into the structural transitions of myosin-V upon ADP release and binding of AppNHp, as well as the actomyosin interface. In addition, they show how myosin is able to specifically alter the structure of F-actin. The unprecedented number of high-resolution structures of a single myosin finally enabled us to assemble a nearly complete structural model of the myosin-V motor cycle and describe the molecular principles of force production.

中文翻译：

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三种核苷酸状态下肌动球蛋白-V 复合物的高分辨率结构提供了对力产生机制的见解

分子运动肌球蛋白在其产生力的摩托车周期中经历了一系列主要的结构转变。潜在机制及其与 ATP 水解和肌动蛋白结合的耦合仅被部分了解，主要是由于肌球蛋白的肌动蛋白结合状态的结构数据稀少。在这里，我们报告了 26 种高分辨率冷冻 EM 结构的 actomyosin-V 复合物在强 ADP、严格性和先前未见的结合 ATP 类似物 AppNHp 的严格后过渡状态。这些结构揭示了肌球蛋白在每种状态下的高度灵活性，并为了解 ADP 释放和 AppNHp 结合后肌球蛋白-V 的结构转变以及肌动球蛋白界面提供了宝贵的见解。此外，他们展示了肌球蛋白如何能够特异性地改变 F-肌动蛋白的结构。