Structural basis of transcription-translation coupling

• DOI: 10.1126/science.abb5317
• Publication Date: 2020-08-20T23:17:12Z
• Authors: Chengyuan Wang; Vadim Molodtsov; Emre Firlar; Jason T. Kaelber; Gregor Blaha; Min Su; Richard H. Ebright
• Keywords: Transcription; Bacterial transcription

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