Splitting of the posttermination ribosome into subunits by the concerted action of RRF and EF-G

Mol Cell. 2005 Jun 10;18(6):675-86. doi: 10.1016/j.molcel.2005.05.016.

Abstract

After peptide release by a class-1 release factor, the ribosomal subunits must be recycled back to initiation. We have demonstrated that the distance between a strong Shine-Dalgarno (SD) sequence and a codon in the P site is crucial for the binding stability of the deacylated tRNA in the P site of the posttermination ribosome and the in-frame maintenance of its mRNA. We show that the elongation factor EF-G and the ribosomal recycling factor RRF split the ribosome into subunits in the absence of initiation factor 3 (IF3) by a mechanism that requires both GTP and GTP hydrolysis. Taking into account that EF-G in the GTP form and RRF bind with positive cooperativity to the free 50S subunit but with negative cooperativity to the 70S ribosome, we suggest a mechanism for ribosome recycling that specifies distinct roles for EF-G, RRF, and IF3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Kinetics
  • Models, Molecular
  • Nucleic Acid Conformation
  • Peptide Elongation Factor G / metabolism*
  • Protein Biosynthesis
  • RNA, Messenger / chemistry
  • RNA, Messenger / metabolism*
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism
  • Ribosomal Proteins / metabolism*
  • Ribosomes / metabolism*
  • Ribosomes / ultrastructure

Substances

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