Escherichia coli NusG Links the Lead Ribosome with the Transcription Elongation Complex
Escherichia coli NusG Links the Lead Ribosome with the Transcription Elongation Complex
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DOI：
10.1016/j.isci.2020.101352
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发表时间：
2020-08-21
期刊：
影响因子：
5.8
通讯作者：
Frank, Joachim
中科院分区：
文献类型：
--
作者：
Washburn, Robert S.;Zuber, Philipp K.;Frank, Joachim
细菌的转录和翻译在物理上是偶联的，但这种偶联是否可能是由大肠杆菌中的双域蛋白N利用物质(NUS)G介导的，这一点已经知道了50多年了。在这里，我们结合综合结构生物学和功能分析来提供确凿的证据，证明NusG通过接触RNA聚合酶和核糖体，可以在物理上将转录与翻译联系起来。我们提出了NusG：70S核糖体复合体的冷冻电子显微镜结构和核磁共振数据，揭示了NusG同时与RNAP和完整的70S核糖体结合，为NusG介导的偶联提供了第一个直接的结构证据。此外，体内报告分析表明，NusG的招募发生在转录后期，并强烈依赖于翻译。因此，我们的数据表明，COUR_Ag最初通过直接的RNAP：核糖体接触而发生，然后由NusG介导。
It has been known for more than 50 years that transcription and translation are physically coupled in bacteria, but whether or not this coupling may be mediated by the two-domain protein N-utilization substance (Nus) G in Escherichia coli is still heavily debated. Here, we combine integrative structural biology and functional analyses to provide conclusive evidencc that NusG can physically link transcription with translation by contacting both RNA polymerase and the ribosome. We present a cryo-electron microscopy structure of a NusG:70S ribosome complex and nuclear magnetic resonance spectroscopy data revealing simultaneous binding of NusG to RNAP and the intact 70S ribosome, providing the first direct structural evidence for NusG-mediated coupling. Furthermore, in vivo reporter assays show that recruitment of NusG occurs late in transcription and strongly depends on translation. Thus, our data suggest that cour_Ag occurs initially via direct RNAP:ribosome contacts and is then mediated by NusG.