Finn R D, Orlova E V, Gowen B, Buck M, van Heel M
Departments of Biochemistry and Biology, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK.
EMBO J. 2000 Dec 15;19(24):6833-44. doi: 10.1093/emboj/19.24.6833.
Multisubunit RNA polymerase is an essential enzyme for regulated gene expression. Here we report two Escherichia coli RNA polymerase structures: an 11.0 A structure of the core RNA polymerase and a 9.5 A structure of the sigma(70) holoenzyme. Both structures were obtained by cryo-electron microscopy and angular reconstitution. Core RNA polymerase exists in an open conformation. Extensive conformational changes occur between the core and the holoenzyme forms of the RNA polymerase, which are largely associated with movements in ss'. All common RNA polymerase subunits (alpha(2), ss, ss') could be localized in both structures, thus suggesting the position of sigma(70) in the holoenzyme.
多亚基RNA聚合酶是调控基因表达所必需的酶。在此我们报道了两种大肠杆菌RNA聚合酶结构：核心RNA聚合酶的11.0 Å结构和σ⁷⁰全酶的9.5 Å结构。这两种结构均通过冷冻电子显微镜和角度重构获得。核心RNA聚合酶以开放构象存在。RNA聚合酶的核心形式和全酶形式之间发生了广泛的构象变化，这些变化在很大程度上与β'亚基的运动相关。所有常见的RNA聚合酶亚基（α₂、β、β'）在两种结构中均可定位，从而表明了σ⁷⁰在全酶中的位置。
