Ray Pampa, Hall Richard J, Finn Robert D, Chen Shaoxia, Patwardhan Ardan, Buck Martin, van Heel Marin
Department of Biological Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
J Mol Biol. 2005 Nov 25;354(2):201-5. doi: 10.1016/j.jmb.2005.09.057. Epub 2005 Oct 5.
RNA polymerase from the mesophile Escherichia coli exists in two forms, the core enzyme and the holoenzyme. Using cryo-electron microscopy and single-particle analysis, we have obtained the structure of the complete RNA polymerase from E.coli containing the sigma54 factor within the closed-promoter complex. Comparisons with earlier reconstructions of the core enzyme and the sigma54 holoenzyme reveal the behaviour of this major variant RNA polymerase in defined functional states. The binding of DNA leads to significant conformational changes in the enzyme's catalytic subunits, apparently a necessity for the initiation of enhancer-dependent promoter-specific transcription.
嗜温菌大肠杆菌的RNA聚合酶以两种形式存在，即核心酶和全酶。通过冷冻电子显微镜和单颗粒分析，我们获得了来自大肠杆菌的完整RNA聚合酶的结构，该酶在封闭启动子复合物中含有σ54因子。与核心酶和σ54全酶的早期重建结构进行比较，揭示了这种主要变体RNA聚合酶在特定功能状态下的行为。DNA的结合导致酶的催化亚基发生显著的构象变化，这显然是增强子依赖性启动子特异性转录起始所必需的。
