EMD-21482
Escherichia coli transcription-translation complex D1 (TTC-D1) containing mRNA with a 27 nt long spacer, NusG, and fMet-tRNAs at E-site and P-site
EMD-21482
Single-particle10.0 Å
Deposition: 27/02/2020
Map released: 02/09/2020
Last modified: 06/11/2024
Sample Organism:
Escherichia coli
Sample: Escherichia coli transcription-translation complex D1 (TTC-D1) containing mRNA with a 27 nt long spacer, NusG, and fMet-tRNAs at E-site and P-site
Fitted models: 6vz2 (Avg. Q-score: 0.037)
Deposition Authors: Molodtsov V , Wang C
Sample: Escherichia coli transcription-translation complex D1 (TTC-D1) containing mRNA with a 27 nt long spacer, NusG, and fMet-tRNAs at E-site and P-site
Fitted models: 6vz2 (Avg. Q-score: 0.037)
Deposition Authors: Molodtsov V , Wang C
Structural basis of transcription-translation coupling.
Wang C ,
Molodtsov V ,
Firlar E ,
Kaelber JT ,
Blaha G ,
Su M ,
Ebright RH
(2020) Science , 369 , 1359 - 1365
(2020) Science , 369 , 1359 - 1365
Abstract:
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.
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.