8URI

Escherichia coli transcription-translation coupled complex class B (TTC-B) containing RfaH bound to ops signal, NusA, mRNA with a 27 nt long spacer, and fMet-tRNAs in E-site and P-site of the ribosome

This is a non-PDB format compatible entry.

Summary for 8URI

• Entry DOI: 10.2210/pdb8uri/pdb
• EMDB information: 42493
• Descriptor: Ribosomal protein L21, E-site and P-site fMet-tRNA, DNA-directed RNA polymerase subunit beta, ... (68 entities in total)
• Functional Keywords: transcription, translation, rfah, gene expression, regulation, ops, ribosome, coupling
• Biological source: Escherichia coli; More
• Total number of polymer chains: 68
• Total formula weight: 2795411.41

Authors

Molodtsov, V.,Wang, C.,Ebright, R.H. (deposition date: 2023-10-26, release date: 2024-05-29, Last modification date: 2024-10-23)

Primary citation

Molodtsov, V.,Wang, C.,Zhang, J.,Kaelber, J.T.,Blaha, G.,Ebright, R.H.
Structural basis of RfaH-mediated transcription-translation coupling.
Nat.Struct.Mol.Biol., 2024

PubMed Abstract: The NusG paralog RfaH mediates bacterial transcription-translation coupling in genes that contain a DNA sequence element, termed an ops site, required for pausing RNA polymerase (RNAP) and for loading RfaH onto the paused RNAP. Here, we report cryo-electron microscopy structures of transcription-translation complexes (TTCs) containing Escherichia coli RfaH. The results show that RfaH bridges RNAP and the ribosome, with the RfaH N-terminal domain interacting with RNAP and the RfaH C-terminal domain interacting with the ribosome. The results show that the distribution of translational and orientational positions of RNAP relative to the ribosome in RfaH-coupled TTCs is more restricted than in NusG-coupled TTCs because of the more restricted flexibility of the RfaH interdomain linker. The results further suggest that the structural organization of RfaH-coupled TTCs in the 'loading state', in which RNAP and RfaH are located at the ops site during formation of the TTC, is the same as the structural organization of RfaH-coupled TTCs in the 'loaded state', in which RNAP and RfaH are located at positions downstream of the ops site during function of the TTC. The results define the structural organization of RfaH-containing TTCs and set the stage for analysis of functions of RfaH during translation initiation and transcription-translation coupling.

PubMed: 39117885
DOI: 10.1038/s41594-024-01372-w

Experimental method

ELECTRON MICROSCOPY (5.3 Å)