Department of Biochemistry and Molecular Biology and Immunology (B), Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", P.O. Box 4021, Murcia E-30100, Spain.
Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
FEMS Microbiol Lett. 2020 Nov 11;367(20). doi: 10.1093/femsle/fnaa164.
Transcription activation by the Escherichia coli CRP at Class II promoters is dependent on direct interactions between RNA polymerase and CRP, therefore the spatial proximity between both proteins plays a significant role in the ability of CRP to activate transcription. Using both in vivo and in vitro techniques, here we demonstrate that the CRP K100 positive charge, adjacent to AR2, is required for full promoter activity when CRP is optimally positioned. Accordingly, K100 mediated activation is very position-dependent and our data confirm that the largest impact of the K100 status on transcription activation occurs when the spacing between the CRP binding site and the A2 of the -10 element is 22 bp. From the results of this study and the progress in the understanding about open complex DNA scrunching, we propose that CRP-dependent promoters should now be numbered by the distance from the center of the DNA site for CRP and the most highly conserved base at position 2 of the -10 hexamer in bacterial promoters.
大肠杆菌 CRP 在 II 类启动子上的转录激活依赖于 RNA 聚合酶和 CRP 之间的直接相互作用，因此两种蛋白质之间的空间接近程度在 CRP 激活转录的能力中起着重要作用。在这里，我们使用体内和体外技术证明，当 CRP 处于最佳位置时，位于 AR2 旁边的 CRP K100 正电荷对于充分的启动子活性是必需的。因此，K100 介导的激活非常依赖于位置，并且我们的数据证实，当 CRP 结合位点和 -10 元件的 A2 之间的间隔为 22 bp 时，K100 状态对转录激活的影响最大。根据这项研究的结果和对开放复合物 DNA 扭曲的理解的进展，我们提出应该根据 CRP 和细菌启动子中 -10 六聚体第 2 位最保守碱基的 DNA CRP 结合位点的中心与位置之间的距离来对 CRP 依赖性启动子进行编号。
