Tao K, Fujita N, Ishihama A
Radioisotope Centre, University of Tokyo, Japan.
Mol Microbiol. 1993 Mar;7(6):859-64. doi: 10.1111/j.1365-2958.1993.tb01176.x.
The role of the alpha subunit of Escherichia coli RNA polymerase in transcription activation by the OxyR protein was investigated using in-vitro-reconstituted RNA polymerase containing alpha subunits carrying C-terminal truncations or an amino acid substitution. Mutant RNA polymerases failed to respond to transcription activation of the E. coli OxyR-dependent promoters. DNase I footprinting analysis indicates that the OxyR protein exerts a co-operative effect on the binding of wild-type RNA polymerase, but not the mutant RNA polymerases, to the katG promoter. Together, these results suggest that direct protein-protein contact between the OxyR protein and the C-terminal contact site I region of the RNA polymerase alpha subunit plays an essential role in transcription activation at the OxyR-dependent promoters.
利用含有携带C端截短或氨基酸替代的α亚基的体外重组RNA聚合酶，研究了大肠杆菌RNA聚合酶α亚基在OxyR蛋白转录激活中的作用。突变的RNA聚合酶未能对大肠杆菌OxyR依赖性启动子的转录激活作出反应。DNase I足迹分析表明，OxyR蛋白对野生型RNA聚合酶与katG启动子的结合发挥协同作用，但对突变的RNA聚合酶则不然。这些结果共同表明，OxyR蛋白与RNA聚合酶α亚基的C端接触位点I区域之间的直接蛋白质-蛋白质接触在OxyR依赖性启动子的转录激活中起关键作用。
