Correlated conformational events in EF-G and the ribosome regulate translocation

Nat Struct Mol Biol. 2010 Dec;17(12):1470-7. doi: 10.1038/nsmb.1925. Epub 2010 Nov 7.


In bacteria, the translocation of tRNA and mRNA with respect to the ribosome is catalyzed by the conserved GTPase elongation factor-G (EF-G). To probe the rate-determining features in this process, we imaged EF-G-catalyzed translocation from two unique structural perspectives using single-molecule fluorescence resonance energy transfer. The data reveal that the rate at which the ribosome spontaneously achieves a transient, 'unlocked' state is closely correlated with the rate at which the tRNA-like domain IV-V element of EF-G engages the A site. After these structural transitions, translocation occurs comparatively fast, suggesting that conformational processes intrinsic to the ribosome determine the rate of translocation. Experiments conducted in the presence of non-hydrolyzable GTP analogs and specific antibiotics further reveal that allosterically linked conformational events in EF-G and the ribosome mediate rapid, directional substrate movement and EF-G release.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Escherichia coli / genetics*
  • Fluorescence Resonance Energy Transfer
  • Kinetics
  • Models, Genetic
  • Peptide Elongation Factor G / chemistry*
  • Peptide Elongation Factor G / physiology
  • Protein Biosynthesis
  • Protein Structure, Tertiary
  • RNA, Transfer / metabolism
  • Ribosomes / chemistry*
  • Ribosomes / physiology


  • Peptide Elongation Factor G
  • RNA, Transfer