The structure of an elongation factor G-ribosome complex captured in the absence of inhibitors

Nucleic Acids Res. 2018 Apr 6;46(6):3211-3217. doi: 10.1093/nar/gky081.


During translation's elongation cycle, elongation factor G (EF-G) promotes messenger and transfer RNA translocation through the ribosome. Until now, the structures reported for EF-G-ribosome complexes have been obtained by trapping EF-G in the ribosome. These results were based on use of non-hydrolyzable guanosine 5'-triphosphate (GTP) analogs, specific inhibitors or a mutated EF-G form. Here, we present the first cryo-electron microscopy structure of EF-G bound to ribosome in the absence of an inhibitor. The structure reveals a natural conformation of EF-G·GDP in the ribosome, with a previously unseen conformation of its third domain. These data show how EF-G must affect translocation, and suggest the molecular mechanism by which fusidic acid antibiotic prevents the release of EF-G after GTP hydrolysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Bacterial Proteins / ultrastructure
  • Cryoelectron Microscopy
  • Guanosine Triphosphate / metabolism
  • Hydrolysis
  • Models, Molecular
  • Molecular Conformation
  • Peptide Elongation Factor G / chemistry
  • Peptide Elongation Factor G / metabolism*
  • Peptide Elongation Factor G / ultrastructure
  • Protein Binding
  • Protein Biosynthesis*
  • Protein Conformation
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Transfer / genetics
  • RNA, Transfer / metabolism
  • Ribosomes / chemistry
  • Ribosomes / metabolism*
  • Ribosomes / ultrastructure
  • Thermus thermophilus / metabolism


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