Post-termination Ribosome Intermediate Acts as the Gateway to Ribosome Recycling

Cell Rep. 2017 Jul 5;20(1):161-172. doi: 10.1016/j.celrep.2017.06.028.


During termination of translation, the nascent peptide is first released from the ribosome, which must be subsequently disassembled into subunits in a process known as ribosome recycling. In bacteria, termination and recycling are mediated by the translation factors RF, RRF, EF-G, and IF3, but their precise roles have remained unclear. Here, we use single-molecule fluorescence to track the conformation and composition of the ribosome in real time during termination and recycling. Our results show that peptide release by RF induces a rotated ribosomal conformation. RRF binds to this rotated intermediate to form the substrate for EF-G that, in turn, catalyzes GTP-dependent subunit disassembly. After the 50S subunit departs, IF3 releases the deacylated tRNA from the 30S subunit, thus preventing reassembly of the 70S ribosome. Our findings reveal the post-termination rotated state as the crucial intermediate in the transition from termination to recycling.

Keywords: EF-G; IF3; RRF; recycling; release factor; ribosome; single-molecule fluorescence; stop codon; termination; translation.

MeSH terms

  • Escherichia coli / enzymology
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Peptide Chain Termination, Translational*
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / metabolism
  • Ribosome Subunits, Large, Bacterial / chemistry
  • Ribosome Subunits, Large, Bacterial / metabolism*


  • Escherichia coli Proteins
  • Ribosomal Proteins