Functional visualization of viral molecular motor by hydrogen-deuterium exchange reveals transient states
Functional visualization of viral molecular motor by hydrogen-deuterium exchange reveals transient states
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DOI：
10.1038/nsmb927
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发表时间：
2005-05-01
影响因子：
16.8
通讯作者：
Tuma, R
中科院分区：
文献类型：
--
作者：
Lísal, J;Lam, TT;Tuma, R
分子马达经历周期性构象变化并将化学能转化为机械功。通过氢氘交换和高分辨率质谱法，可视化病毒包装马达，dsRNA噬菌体phi 8的六聚体解旋酶P4的构象动力学。交换动力学的协调变化揭示了一个合作单位，动态连接ATP结合位点和中央RNA结合通道。合作单位是兼容的结构为基础的模型，其中易位是由旋转螺旋介导的。氘标记还揭示了与RNA加载相关的过渡态，其通过打开六聚体环进行。加载机制与其他六聚体解旋酶相似。氢氘交换提供了时间分辨光谱观测和分子机器的高分辨率结构快照之间的重要联系。
Molecular motors undergo cyclical conformational changes and convert chemical energy into mechanical work. The conformational dynamics of a viral packaging motor, the hexameric helicase P4 of dsRNA bacteriophage phi 8, was visualized by hydrogen-deuterium exchange and high-resolution mass spectrometry. Concerted changes of exchange kinetics revealed a cooperative unit that dynamically links ATP-binding sites and the central RNA-binding channel. The cooperative unit is compatible with a structure-based model in which translocation is mediated by a swiveling helix. Deuterium labeling also revealed the transition state associated with RNA loading, which proceeds via opening of the hexameric ring. The loading mechanism is similar to that of other hexameric helicases. Hydrogen-deuterium exchange provides an important link between time-resolved spectroscopic observations and high-resolution structural snapshots of molecular machines.