2p8x
From Proteopedia
|
Fitted structure of ADPR-eEF2 in the 80S:ADPR-eEF2:GDPNP cryo-EM reconstruction
Overview
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.
About this Structure
2P8X is a Protein complex structure of sequences from Saccharomyces cerevisiae and Thermus thermophilus with and as ligands. Full crystallographic information is available from OCA.
Reference
Structures of modified eEF2.80S ribosome complexes reveal the role of GTP hydrolysis in translocation., Taylor DJ, Nilsson J, Merrill AR, Andersen GR, Nissen P, Frank J, EMBO J. 2007 May 2;26(9):2421-31. Epub 2007 Apr 19. PMID:17446867
Page seeded by OCA on Wed Jan 23 15:15:28 2008
