ATP ground- and transition states of bacterial enhancer binding AAA plus ATPases support complex formation with their target protein, σ54
ATP ground- and transition states of bacterial enhancer binding AAA plus ATPases support complex formation with their target protein, σ54
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DOI：
10.1016/j.str.2007.02.007
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发表时间：
2007-04-01
期刊：
影响因子：
5.7
通讯作者：
Nixon, B. Tracy
中科院分区：
文献类型：
--
作者：
Chen, Baoyu;Doucleff, Michaeleen;Nixon, B. Tracy
细菌RNA聚合酶的sigma 54形式的转录起始需要增强子结合蛋白（EBP）水解ATP。我们提出了基于SAS的解决方案结构的EBP NtrC 1从Aquifex aeolicus在不同的核苷酸状态。载脂蛋白的结构以及与AMPPNP或ADP-BeFx（基态模拟物）或ADP-AlFx（过渡态模拟物）或ADP（产物）结合的结构显示出接触聚合酶的GAFTGA环的位置的实质性变化，特别是在从载脂蛋白状态转化为ADP-BeFx状态以及从ADP-AlFx状态转化为ADP状态时。ATP类似物的结合稳定了ATP酶的寡聚体形式及其与sigma 54的结合，其中ADP-AIF的作用最大。这些数据表明，ATP结合促进稳定EBP和σ 54之间的复合物的构象变化，而随后的水解和磷酸盐释放驱动打开聚合酶/启动子复合物所需的构象变化。
Transcription initiation by the sigma 54 form of bacterial RNA polymerase requires hydrolysis of ATP by an enhancer binding protein (EBP). We present SAS-based solution structures of the ATPase domain of the EBP NtrC1 from Aquifex aeolicus in different nucleotide states. Structures of apo protein and that bound to AMPPNP or ADP-BeFx (ground-state mimics), or ADP-AlFx (a transition-state mimic), or ADP (product) show substantial changes in the position of the GAFTGA loops that contact polymerase, particularly upon conversion from the apo state to the ADP-BeFx state, and from the ADP-AlFx state to the ADP state. Binding of the ATP analogs stabilizes the oligomeric form of the ATPase and its binding to sigma 54, with ADP-AIF, having the largest effect. These data indicate that ATP binding promotes a conformational change that stabilizes complexes between EBPs and sigma 54, while subsequent hydrolysis and phosphate release drive the conformational change needed to open the polymerase/promoter complex.