Cryo-EM structure of an Escherichia coli coupled transcription-translation complex B3 (TTC-B3) containing an mRNA with a 27 nt long spacer, transcription factors NusA and NusG, and fMet-tRNAs at P-site and E-site
In bacteria, transcription and translation are coupled processes in which the movement of RNA polymerase (RNAP)-synthesizing messenger RNA (mRNA) is coordinated with the movement of the first ribosome-translating mRNA. Coupling is modulated by the transcription factors NusG (which is thought to bridge RNAP and the ribosome) and NusA. Here, we report cryo-electron microscopy 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.
Organizational Affiliation:
Waksman Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
For questions/corrections to specific PDB entries, including citation updates: email deposit-help@mail.wwpdb.org
Thank you for providing your feedback! Someone will be in touch with you shortly. This window will automatically close in 5 seconds.
Apologies, our feedback server is currently unavailable and we are troubleshooting the issue. In the meantime, please copy and paste the below information into an email addressed to info@rcsb.org