Molecular Anatomy of RNA Polymerase

转录是通过控制RNA聚合酶的启动子选择性来调节的。细菌RNA聚合酶由2α、1β、1β‘和1sigma四个亚基组成。为了了解RNA聚合酶的启动子识别特性如何与转录因子相互作用，本研究对大肠杆菌RNA聚合酶进行了分子解剖，重点研究了RNA聚合酶亚基与各种转录因子的接触位点定位。结果表明，转录因子可以根据RNA聚合酶上的接触位点进行分类。发现I类转录因子与位于α亚基C-末端区域的接触位点I相接触，而II类转录因子与聚集在Sigma亚基C-末端区域的接触位点II相接触。精细定位表明，RNA聚合酶和转录因子之间的蛋白质-蛋白质通讯涉及两侧狭窄的区域，每个区域由大约10个氨基酸残基组成的表位大小组成。同时，还进行了RNA聚合酶亚基之间的接触位点定位。

Transcription is regulated by controlling the promoter selectivity of RNA polymerase. Bacterial RNA polymerase is composed of four major subunits, 2alpha, 1beta, 1beta' and 1sigma subunit. In order to understand how the promoter recognition properties of RNA polymerase is controlled by interaction with transcription factors, we carried out in this research the molecular anatomy of Escherichi coli RNA polymerase, in particular focussing on the contact site mapping on RNA polymerase subunits with various transcription factors. Results indicate that transcription factors can be classified based on the contact site on RNA polymerase. Class-I transcription factors were found to contact with the contact site I located at the C-terminal region of alpha subunit, while class-II factors make contact with the contact site II clustered in the C-terminal region of sigma subunit. Fine mapping revealed that the protein-protein communications between RNA polymerase and transcription factors involve narrow regions on both sides, each being composed of epitope size consisting of about 10 amino acid residues. In parallel, contact site mapping between RNA polymerase subunits has also been carried out.