Structure of the GTP Form of Elongation Factor 4 (EF4) Bound to the Ribosome

J Biol Chem. 2016 Jun 17;291(25):12943-50. doi: 10.1074/jbc.M116.725945. Epub 2016 May 2.

Abstract

Elongation factor 4 (EF4) is a member of the family of ribosome-dependent translational GTPase factors, along with elongation factor G and BPI-inducible protein A. Although EF4 is highly conserved in bacterial, mitochondrial, and chloroplast genomes, its exact biological function remains controversial. Here we present the cryo-EM reconstitution of the GTP form of EF4 bound to the ribosome with P and E site tRNAs at 3.8-Å resolution. Interestingly, our structure reveals an unrotated ribosome rather than a clockwise-rotated ribosome, as observed in the presence of EF4-GDP and P site tRNA. In addition, we also observed a counterclockwise-rotated form of the above complex at 5.7-Å resolution. Taken together, our results shed light on the interactions formed between EF4, the ribosome, and the P site tRNA and illuminate the GTPase activation mechanism at previously unresolved detail.

Keywords: EF4; LepA; cryo-EM; ribosome structure; translation; translation elongation factor; translational GTPase factor; translocation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Catalytic Domain
  • Cryoelectron Microscopy
  • GTP Phosphohydrolase-Linked Elongation Factors / chemistry*
  • Guanosine Diphosphate / chemistry
  • Guanosine Triphosphate / chemistry
  • Hydrogen Bonding
  • Hydrolysis
  • Models, Molecular
  • Protein Binding
  • Ribosome Subunits, Large, Bacterial / chemistry*
  • Ribosome Subunits, Small, Bacterial / chemistry*
  • Thermus thermophilus*

Substances

  • Bacterial Proteins
  • Guanosine Diphosphate
  • Guanosine Triphosphate
  • GTP Phosphohydrolase-Linked Elongation Factors

Associated data

  • PDB/4W2E
  • PDB/5AA0