Topology of the RNA polymerase active center probed by chimeric rifampicin-nucleotide compounds.
Topology of the RNA polymerase active center probed by chimeric rifampicin-nucleotide compounds.
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通过嵌合利福平-核苷酸化合物探测 RNA 聚合酶活性中心的拓扑结构。
DOI：
10.1073/pnas.91.25.12036
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发表时间：
1994
影响因子：
11.1
通讯作者：
Goldfarb,A
中科院分区：
文献类型：
--
作者：
Mustaev,A;Zaychikov,E;Severinov,K;Kashlev,M;Polyakov,A;Nikiforov,V;Goldfarb,A
在大肠杆菌RNA聚合酶（EC 2.7.7.6）中，引发底物、模板DNA和转录抑制剂利福平（Rif）的结合位点的空间组织用嵌合化合物探测，其中Rif共价连接到核糖核苷酸。该化合物以双功能方式与RNA聚合酶结合，并作为RNA链延伸的底物，产生长达8个核苷酸的链，Rif连接到其5'末端。这些产物作为正常转录的有效抑制剂。使用两个配体之间的接头作为标尺，我们确定Rif和引发核苷酸的位点之间的距离约为15 A。位于Rif旁边的接头中的反应性侧基在启动子的-2或-3位置处与DNA的模板链交联。因此，结合Rif是并列的DNA直接上游的起始位点，这表明Rif插头的通道导致RNA的活性中心。
Spatial organization of the binding sites for the priming substrate, the template DNA, and the transcription inhibitor rifampicin (Rif) in Escherichia coli RNA polymerase (EC 2.7.7.6) was probed with chimeric compounds in which Rif is covalently attached to a ribonucleotide. The compounds bind to RNA polymerase in bifunctional manner and serve as substrates for RNA chain extension, yielding chains up to 8 nucleotides in length, with Rif linked to their 5' termini. These products act as potent inhibitors of normal transcription. Using the linker between the two ligands as ruler, we determined the distance between the sites for Rif and the priming nucleotide to be approximately 15 A. A reactive side group placed in the linker next to Rif crosslinks to the template strand of DNA at the -2 or -3 position of the promoter. Thus, bound Rif is juxtaposed to DNA immediately upstream of the start site, suggesting that Rif plugs the channel leading RNA out of the active center.
影响因子：
4.3
作者：
H. Sambrook
通讯作者：
H. Sambrook