4V7B

Visualization of two tRNAs trapped in transit during EF-G-mediated translocation

This is a non-PDB format compatible entry.

Summary for 4V7B

• Entry DOI: 10.2210/pdb4v7b/pdb
• EMDB information: 5775
• Descriptor: 16S ribosomal RNA, 30S ribosomal protein S10, 30S ribosomal protein S11, ... (60 entities in total)
• Functional Keywords: translocation intermediate, ef-g, head swiveling, ribosome-translation complex, ribosome/translation
• Biological source: Escherichia coli; More
• Total number of polymer chains: 58
• Total formula weight: 2301175.60

Authors

Ramrath, D.J.F.,Lancaster, L.,Sprink, T.,Mielke, T.,Loerke, J.,Noller, H.F.,Spahn, C.M.T. (deposition date: 2013-10-27, release date: 2014-07-09, Last modification date: 2019-12-18)

Primary citation

Ramrath, D.J.,Lancaster, L.,Sprink, T.,Mielke, T.,Loerke, J.,Noller, H.F.,Spahn, C.M.
Visualization of two transfer RNAs trapped in transit during elongation factor G-mediated translocation.
Proc.Natl.Acad.Sci.USA, 110:20964-20969, 2013

PubMed Abstract: During protein synthesis, coupled translocation of messenger RNAs (mRNA) and transfer RNAs (tRNA) through the ribosome takes place following formation of each peptide bond. The reaction is facilitated by large-scale conformational changes within the ribosomal complex and catalyzed by elongtion factor G (EF-G). Previous structural analysis of the interaction of EF-G with the ribosome used either model complexes containing no tRNA or only a single tRNA, or complexes where EF-G was directly bound to ribosomes in the posttranslocational state. Here, we present a multiparticle cryo-EM reconstruction of a translocation intermediate containing two tRNAs trapped in transit, bound in chimeric intrasubunit ap/P and pe/E hybrid states. The downstream ap/P-tRNA is contacted by domain IV of EF-G and P-site elements within the 30S subunit body, whereas the upstream pe/E-tRNA maintains tight interactions with P-site elements of the swiveled 30S head. Remarkably, a tight compaction of the tRNA pair can be seen in this state. The translocational intermediate presented here represents a previously missing link in understanding the mechanism of translocation, revealing that the ribosome uses two distinct molecular ratchets, involving both intra- and intersubunit rotational movements, to drive the synchronous movement of tRNAs and mRNA.

PubMed: 24324168
DOI: 10.1073/pnas.1320387110

Experimental method

ELECTRON MICROSCOPY (6.8 Å)