罗格斯大学Richard H. Ebright研究团队近日取得一项新成果。经过不懈努力，他们的发现了转录翻译耦合结构基础。 该研究于2020年8月20号发表于《科学》。

该课题组人员利用cryoEM研究了大肠杆菌转录-翻译复合物（TTC）结构，其中包含RNAP和核糖体活性中心P位点之间的不同长度的mRNA间隔区。含有短间隔子的TTC的结构显示出与NusG桥接和NusA结合（TTC-A；先前称为“ expressome”）不兼容的状态。包含更长间隔基团的TTC的结构揭示了与NusG桥接和NusA结合（TTC-B）兼容的新状态，并揭示了NusG桥和NusA如何结合。他们认为TTC-B介导NusG-和NusA依赖的转录-翻译偶联。

据了解，在细菌中转录和翻译是耦合过程，其中合成mRNA的RNA聚合酶（RNAP）的过程与翻译第一核糖体的mRNA的过程相协调。耦合受转录因子NusG和NusA的调节，NusG被认为是桥接RNAP和核糖体的桥梁。

附：英文原文

Title: Structural basis of transcription-translation coupling

Author: Chengyuan Wang, Vadim Molodtsov, Emre Firlar, Jason T. Kaelber, Gregor Blaha, Min Su, Richard H. Ebright

Issue&Volume: 2020/08/20

Abstract: Abstract In bacteria, transcription and translation are coupled processes, in which movement of RNA polymerase (RNAP) syn thesizing mRNA is coordinated with movement of the first ribosome translating mRNA. Coupling is modulated by the transcription factors NusG–which is thought to bridge RNAP and ribosome–and NusA. Here, we report cryo-EM structures of Escherichia coli transcription-translation complexes (TTCs) containing different-length mRNA spacers between RNAP and the ribosome active-center P-site. Structures of TTCs containing short spacers show a state incompatible with NusG bridging and NusA binding (TTC-A; previously termed “expressome”). Structures of TTCs containing longer spacers reveal a new state compatible with NusG bridging and NusA binding (TTC-B) and reveal how NusG bridges and NusA binds. We propose that TTC-B mediates NusG- and NusA-dependent transcription-translation coupling.

DOI: 10.1126/science.abb5317

Source: https://science.sciencemag.org/content/early/2020/08/19/science.abb5317