Nguyen L H, Burgess R R
McArdle Laboratory for Cancer Research, University of Wisconsin-Madison 53706, USA.
Biochemistry. 1997 Feb 18;36(7):1748-54. doi: 10.1021/bi961175h.
We have investigated the interactions of Escherichia coli sigma 70 and sigma S holoenzyme RNA polymerases (E sigma S and E sigma 70) with the stationary-phase-specific bolAp1 promoter by various footprinting methods in vitro. E sigma S and E sigma 70 have been shown to transcribe the bolApl promoter in vitro. We have determined the effects of salt and holoenzyme concentrations on E sigma S and E sigma 70 open complex formation at the bolAp1 promoter in vitro. We have obtained a high-resolution hydroxyl radical (OH.) footprint of E sigma S and E sigma 70 on the bolApl promoter. The OH. footprinting data show remarkable similarities between the footprints of the heparin-resistant transcription complexes of the two holoenzymes which have the same +1 transcription start site. However, there are distinctive differences in the protection patterns in the region between -20 and -10 of the bolAp1 promoter. KMnO4 reactivity assays reveal that, at 37 degrees C, both holoenzymes produced similar but not identical patterns of reactivities.
我们通过多种体外足迹法研究了大肠杆菌σ70和σS全酶RNA聚合酶（EσS和Eσ70）与稳定期特异性bolAp1启动子的相互作用。已证明EσS和Eσ70可在体外转录bolAp1启动子。我们确定了盐浓度和全酶浓度对体外bolAp1启动子上EσS和Eσ70开放复合物形成的影响。我们获得了EσS和Eσ70在bolAp1启动子上的高分辨率羟基自由基（OH·）足迹。OH·足迹数据显示，具有相同+1转录起始位点的两种全酶的肝素抗性转录复合物的足迹之间存在显著相似性。然而，在bolAp1启动子-20至-10区域的保护模式存在明显差异。高锰酸钾反应性分析表明，在37℃时，两种全酶产生的反应性模式相似但不完全相同。
