2P8W: Fitted Structure Of Eef2 In The 80s:eef2:gdpnp Cryo-Em Reconstruction

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.
PDB ID: 2P8WDownload
MMDB ID: 46527
PDB Deposition Date: 2007/3/23
Updated in MMDB: 2007/10
Experimental Method:
electron microscopy
Resolution: 11.3  Å
Source Organism:
Saccharomyces cerevisiae
Similar Structures:
Biological Unit for 2P8W: dimeric; determined by author
Molecular Components in 2P8W
Label Count Molecule
Proteins (2 molecules)
Elongation Factor 2(Gene symbol: EFT2)
Molecule annotation
Elongation Factor Tu-b(Gene symbol: TTHA0251)
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB