The two alpha subunits of Escherichia coli RNA polymerase are asymmetrically arranged and contact different halves of the DNA upstream element
The two alpha subunits of Escherichia coli RNA polymerase are asymmetrically arranged and contact different halves of the DNA upstream element
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DOI：
10.1073/pnas.94.5.1709
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发表时间：
1997-03-04
影响因子：
11.1
通讯作者：
Ishihama, A
中科院分区：
文献类型：
--
作者：
Murakami, K;Kimura, M;Ishihama, A
大肠杆菌的RNA聚合酶核心酶由两个α亚基和一个β和β '亚基组成。RNA聚合酶亚基的C-末端结构域在与I类转录因子和启动子DNA的上游（UP）元件的分子通讯中起关键作用，使用相同的蛋白质表面，为了鉴定两个α亚基的功能作用中可能的差异，我们已经开发了一种重组方法，用于含有两个不同α亚基衍生物的杂交RNA聚合酶，（“定向α-异二聚体”）。UP元件DNA上的两个α C-末端结构域的结合位点通过基于羟基自由基的DNA切割介导的bf（p-bromoacetamidobenzyl）-EDTA确定。Fe结合在一个或两个α亚基的UP识别表面上的Cys-269。结果清楚地表明，两个α亚基串联结合到rrnBP 1 UP元件的两个螺旋转角，并且β ′-相关α亚基结合到启动子远端区域。
RNA polymerase core enzyme of Escherichia coli is composed of two alpha subunits and one each of the beta and beta' subunits. The C-terminal domain of the RNA polymerase of subunit plays a key role in molecular communications with class I transcription factors and upstream (UP) elements of promoter DNA, using the same protein surface, To identify possible differences in the functional roles of the two alpha subunits, we have developed a reconstitution method for hybrid RNA polymerases containing two distinct alpha subunit derivatives in a defined orientation (''oriented alpha-heterodimer''). The binding sites of two alpha C-terminal domains on the UP element DNA were determined by hydroxyl radical-based DNA cleavage mediated bf (p-bromoacetamidobenzyl)-EDTA . Fe, which was bound at Cys-269 on the UP recognition surface of one or both alpha subunits, The results clearly indicated that the two alpha subunits bind in tandem to two helix turns of the rrnBP1 UP element, and that the beta'-associated alpha subunit is bound to the promoter-distal region.