Structural basis for ribosome recycling by RRF and tRNA

Nat Struct Mol Biol. 2020 Jan;27(1):25-32. doi: 10.1038/s41594-019-0350-7. Epub 2019 Dec 23.


The bacterial ribosome is recycled into subunits by two conserved proteins, elongation factor G (EF-G) and the ribosome recycling factor (RRF). The molecular basis for ribosome recycling by RRF and EF-G remains unclear. Here, we report the crystal structure of a posttermination Thermus thermophilus 70S ribosome complexed with EF-G, RRF and two transfer RNAs at a resolution of 3.5 Å. The deacylated tRNA in the peptidyl (P) site moves into a previously unsuspected state of binding (peptidyl/recycling, p/R) that is analogous to that seen during initiation. The terminal end of the p/R-tRNA forms nonfavorable contacts with the 50S subunit while RRF wedges next to central inter-subunit bridges, illuminating the active roles of tRNA and RRF in dissociation of ribosomal subunits. The structure uncovers a missing snapshot of tRNA as it transits between the P and exit (E) sites, providing insights into the mechanisms of ribosome recycling and tRNA translocation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Crystallography, X-Ray
  • Models, Molecular
  • Peptide Elongation Factor G / chemistry
  • Peptide Elongation Factor G / metabolism
  • Protein Conformation
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism*
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / metabolism*
  • Ribosome Subunits, Large, Bacterial / chemistry
  • Ribosome Subunits, Large, Bacterial / metabolism
  • Ribosomes / chemistry
  • Ribosomes / metabolism*
  • Thermus thermophilus / chemistry
  • Thermus thermophilus / metabolism*


  • Bacterial Proteins
  • Peptide Elongation Factor G
  • Ribosomal Proteins
  • ribosome releasing factor
  • RNA, Transfer