法国基因分子细胞生物研究所综合结构生物学系Albert Weixlbaumer组的一项最新研究了细菌中转录-翻译偶联和碰撞的结构基础。 相关论文于2020年8月20号发表于《科学》杂志。

研究人员展示了一系列结构，通过电子冷冻显微镜确定了这些结构代表的未耦合，耦合和碰撞的表达组状态。核糖体和核糖体可能接触RNA聚合酶（RNAP）之间的桥可以由转录因子NusG形成，从而稳定了原本可变的相互作用界面。插入的mRNA的缩短会导致实质性重排，使核糖体进入通道与RNAP退出通道对齐。在这种碰撞的复合物中，NusG链不再可能形成。这些结构揭示了转录和翻译之间的协调机制，并为将来的研究提供了框架。

据悉，原核生物信使RNA（mRNA）在转录时会被翻译。先驱性核糖体可能会接触RNA聚合酶（RNAP），形成称为表达基因组的超分子复合物。人们对表达组组装的基础及其对转录和翻译的影响了解甚少。本文提供了研究基础理解。

附：英文原文

Title: Structural basis of transcription-translation coupling and collision in bacteria

Author: Michael William Webster, Maria Takacs, Chengjin Zhu, Vita Vidmar, Ayesha Eduljee, Mo’men Abdelkareem, Albert Weixlbaumer

Issue&Volume: 2020/08/20

Abstract: Abstract Prokaryotic messenger RNAs (mRNAs) are translated as they are transcribed. The pioneering ribosome potentially contacts RNA polymerase (RNAP), forming a supramolecular complex known as the expressome. The basis of expressome assembly and its consequences for transcription and translation are poorly understood. Here we present a series of structures representing uncoupled, coupled and collided expressome states determined by electron cryomicroscopy. A bridge between the ribosome and RNAP can be formed by the transcription factor NusG, stabilizing an otherwise variable interaction interface. Shortening of the intervening mRNA causes a substantial rearrangement that aligns the ribosome entrance-channel to the RNAP exit-channel. In this collided complex, NusG-linkage is no longer possible. These structures reveal mechanisms of coordination between transcription and translation and provide a framework for future study.

DOI: 10.1126/science.abb5036

Source: https://science.sciencemag.org/content/early/2020/08/19/science.abb5036