Structures of modified eEF2 80S ribosome complexes reveal the role of GTP hydrolysis in translocation

EMBO J. 2007 May 2;26(9):2421-31. doi: 10.1038/sj.emboj.7601677. Epub 2007 Apr 19.


On the basis of kinetic data on ribosome protein synthesis, the mechanical energy for translocation of the mRNA-tRNA complex is thought to be provided by GTP hydrolysis of an elongation factor (eEF2 in eukaryotes, EF-G in bacteria). We have obtained cryo-EM reconstructions of eukaryotic ribosomes complexed with ADP-ribosylated eEF2 (ADPR-eEF2), before and after GTP hydrolysis, providing a structural basis for analyzing the GTPase-coupled mechanism of translocation. Using the ADP-ribosyl group as a distinct marker, we observe conformational changes of ADPR-eEF2 that are due strictly to GTP hydrolysis. These movements are likely representative of native eEF2 motions in a physiological context and are sufficient to uncouple the mRNA-tRNA complex from two universally conserved bases in the ribosomal decoding center (A1492 and A1493 in Escherichia coli) during translocation. Interpretation of these data provides a detailed two-step model of translocation that begins with the eEF2/EF-G binding-induced ratcheting motion of the small ribosomal subunit. GTP hydrolysis then uncouples the mRNA-tRNA complex from the decoding center so translocation of the mRNA-tRNA moiety may be completed by a head rotation of the small subunit.

Publication types

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

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Ascomycota / metabolism
  • Cryoelectron Microscopy / methods
  • Guanosine Triphosphate / chemistry*
  • Guanosine Triphosphate / metabolism
  • Hydrolysis
  • Models, Molecular*
  • Molecular Sequence Data
  • Peptide Elongation Factor 2 / chemistry*
  • Peptide Elongation Factor 2 / metabolism
  • Peptide Elongation Factor G / chemistry
  • Peptide Elongation Factor G / metabolism
  • Protein Structure, Tertiary
  • RNA Transport
  • RNA, Messenger / chemistry
  • RNA, Messenger / metabolism
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism
  • Ribosomes / chemistry*
  • Ribosomes / metabolism


  • Peptide Elongation Factor 2
  • Peptide Elongation Factor G
  • RNA, Messenger
  • Adenosine Diphosphate
  • Guanosine Triphosphate
  • RNA, Transfer

Associated data

  • GENBANK/EMD01342
  • GENBANK/EMD01343
  • GENBANK/EMD01344
  • GENBANK/EMD01345
  • PDB/2P8W
  • PDB/2P8X
  • PDB/2P8Y
  • PDB/2P8Z