EF-G and EF4: translocation and back-translocation on the bacterial ribosome

Nat Rev Microbiol. 2014 Feb;12(2):89-100. doi: 10.1038/nrmicro3176. Epub 2013 Dec 23.

Abstract

Ribosomes translate the codon sequence of an mRNA into the amino acid sequence of the corresponding protein. One of the most crucial events is the translocation reaction, which involves movement of both the mRNA and the attached tRNAs by one codon length and is catalysed by the GTPase elongation factor G (EF-G). Interestingly, recent studies have identified a structurally related GTPase, EF4, that catalyses movement of the tRNA2-mRNA complex in the opposite direction when the ribosome stalls, which is known as back-translocation. In this Review, we describe recent insights into the mechanistic basis of both translocation and back-translocation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacteria / genetics*
  • Bacteria / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology
  • Bacterial Translocation*
  • Binding Sites
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism*
  • Guanosine Triphosphate / metabolism
  • Hydrolysis
  • Models, Molecular*
  • Peptide Elongation Factor G / genetics
  • Peptide Elongation Factor G / metabolism*
  • Protein Biosynthesis
  • RNA, Messenger / metabolism
  • RNA, Transfer / metabolism
  • Ribosomes / physiology*

Substances

  • Bacterial Proteins
  • Peptide Elongation Factor G
  • RNA, Messenger
  • Guanosine Triphosphate
  • RNA, Transfer
  • GTP Phosphohydrolases