UvrD helicase unwinds DNA one base pair at a time by a two-part power stroke
UvrD helicase unwinds DNA one base pair at a time by a two-part power stroke
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DOI：
10.1016/j.cell.2006.10.049
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发表时间：
2006-12-29
期刊：
影响因子：
64.5
通讯作者：
Yang, Wei
中科院分区：
文献类型：
--
作者：
Lee, Jae Young;Yang, Wei
解旋酶使用来自核苷三磷酸水解的能量来解开基本上涉及核酸的每一个代谢途径中的双螺旋。早期的晶体结构表明，DNA解旋酶以尺蠖的方式沿着单链DNA沿着移位。本文报道了一系列与DNA和ATP水解中间体复合的UvrD解旋酶的晶体结构。这些结构表明，ATP结合单独导致解旋的1个碱基对的定向旋转和翻译的DNA双链体，和ADP和Pi的释放导致易位的发展单链。因此，DNA解旋是通过组合扳手和尺蠖机制中的两部分动力行程来实现的。DNA的旋转角和平移距离将解旋步骤定义为每个水解的ATP 1个碱基对。最后，一个网关ssDNA易位和替代链位移模式可以解释以前报道的不同步长。
Helicases use the energy derived from nucleoside triphosphate hydrolysis to unwind double helices in essentially every metabolic pathway involving nucleic acids. Earlier crystal structures have suggested that DNA helicases translocate along a single-stranded DNA in an inchworm fashion, We report here a series of crystal structures of the UvrD helicase complexed with DNA and ATP hydrolysis intermediates. These structures reveal that ATP binding alone leads to unwinding of 1 base pair by directional rotation and translation of the DNA duplex, and ADP and Pi release leads to translocation of the developing single strand. Thus DNA unwinding is achieved by a two-part power stroke in a combined wrench-and-inchworm mechanism. The rotational angle and translational distance of DNA define the unwinding step to be 1 base pair per ATP hydrolyzed. Finally, a gateway for ssDNA translocation and an alternative strand-displacement mode may explain the varying step sizes reported previously.