Evidence for DNA bending at the T7 RNA polymerase promoter
Evidence for DNA bending at the T7 RNA polymerase promoter
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DOI：
10.1006/jmbi.1999.3418
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发表时间：
2000-02-04
影响因子：
5.6
通讯作者：
Martin, CT
中科院分区：
文献类型：
--
作者：
Ujvári, A;Martin, CT
噬菌体T7RNA聚合酶是唯一一种具有高分辨结构的启动子结合复合体的DNA依赖的RNA聚合酶。最近对更复杂的RNA聚合酶的研究表明，DNA包装在转录的启动中发挥了作用。在这里，环形排列凝胶延迟分析提供了证据，证明聚合酶确实弯曲了它的启动子DNA。一组互补的实验使用了来自一系列相控A束的差异相位，为T7RNA聚合酶启动子DNA的固有和聚合酶诱导的弯曲提供了进一步的证据。复合体中的弯曲被预测为约40-60度，并以转录起始位置的-2至+1为中心，而固有弯曲要小得多(约10度)。根据该配合物最近的晶体结构来看，这些结果表明了一种结合直接导致弯曲的机制。在起始点的弯曲将促进启动转录所需的熔化。(C)2000年学术出版社。
Phage T7 RNA polymerase is the only DNA-dependent RNA polymerase for which we have a high-resolution structure of the promoter-bound complex. Recent studies with the more complex RNA polymerases have suggested a role for DNA wrapping in the initiation of transcription. Here, circular permutation gel retardation assays provide evidence that the polymerase does indeed bend its promoter DNA. A complementary set of experiments employing differential phasing from an array of phased A-tracts provides further evidence for both intrinsic and polymerase-induced bends in the T7 RNA polymerase promoter DNA. The bend in the complex is predicted to be about 40-60 degrees and to be centered around positions -2 to +1, at the start site for transcription, while the intrinsic bend is much smaller (about 10 degrees). These results, viewed in the light of a recent crystal structure for the complex, suggest a mechanism by which binding leads directly to bending. Bending at the start site would then facilitate the melting necessary to initiate transcription. (C) 2000 Academic Press.