The structure of the rigor complex and its implications for the power stroke
The structure of the rigor complex and its implications for the power stroke
复制标题
DOI：
10.1098/rstb.2004.1566
复制
发表时间：
2004-12-29
期刊：
影响因子：
--
通讯作者：
Houdusse, A
中科院分区：
文献类型：
--
作者：
Holmes, KC;Schröder, RR;Houdusse, A
装饰肌动蛋白为研究肌动蛋白与肌凝蛋白之间的强相互作用提供了一个模型系统。冷冻能滤电子显微镜最近获得了以鸡骨骼S L装饰的兔骨骼肌动蛋白的14埃分辨率图，骨骼肌肌动蛋白的交叉桥的晶体结构不能在没有一定变形的情况下拟合到三维电子显微镜图中。然而，一种新发表的无核苷酸肌球蛋白V交叉桥的结构，显然已经处于强结合形式，可以在不扭曲的情况下适应三维重建。这支持了无核苷酸肌凝蛋白V是强结合肌凝蛋白的极好模型的观点，并允许我们描述肌动蛋白-肌凝蛋白界面。在肌凝蛋白V中，开关2元件关闭，尽管杠杆臂向下（动力冲程后）。因此，看起来很可能开关2在动力行程期间不太打开。肌凝蛋白V的结构与鸡骨骼肌肌凝蛋白的结构在核苷酸结合位点和主干β片的弯曲程度上也有所不同。这暗示了一种机制。通过强大的肌动蛋白结合来控制动力冲程。
Decorated actin provides a model system for studying the strong interaction between actin and myosin. Cryo-energy-filter electron microscopy has recently yielded a 14 Angstrom resolution map of rabbit skeletal actin decorated with chicken skeletal S L The crystal structure of the cross-bridge from skeletal chicken myosin could not be fitted into the three-dimensional electron microscope map without some deformation. However, a newly published structure of the nucleotide-free myosin V cross-bridge, which is apparently already in the strong binding form, can be fitted into the three-dimensional reconstruction without distortion. ThiS supports the notion that nucleotide-free myosin V is an excellent model for strongly bound myosin and allows us to describe the actin-myosin interface. In myosin V the switch 2 element is closed although the lever arm is down (post-power stroke). Therefore, it appears likely that switch 2 does not open very much during the power stroke. The myosin V structure also differs from the chicken skeletal myosin structure in the nucleotide-binding site and the degree of bending of the backbone beta-sheet. These suggest a mechanism. for the control of the power stroke by strong actin binding.