3jce

Publication Abstract from PubMed

EF4 catalyzes tRNA back-translocation through an unknown mechanism. We report cryo-EM structures of Escherichia coli EF4 in post- and pretranslocational ribosomes (Post- and Pre-EF4) at 3.7- and 3.2-A resolution, respectively. In Post-EF4, peptidyl-tRNA occupies the peptidyl (P) site, but the interaction between its CCA end and the P loop is disrupted. In Pre-EF4, the peptidyl-tRNA assumes a unique position near the aminoacyl (A) site, denoted the A site/EF4 bound (A/4) site, with a large displacement at its acceptor arm. Mutagenesis analyses suggest that a specific region in the EF4 C-terminal domain (CTD) interferes with base-pairing between the peptidyl-tRNA 3'-CCA and the P loop, whereas the EF4 CTD enhances peptidyl-tRNA interaction at the A/4 site. Therefore, EF4 induces back-translocation by disengaging the tRNA's CCA end from the peptidyl transferase center of the translating ribosome.

EF4 disengages the peptidyl-tRNA CCA end and facilitates back-translocation on the 70S ribosome.,Zhang D, Yan K, Liu G, Song G, Luo J, Shi Y, Cheng E, Wu S, Jiang T, Lou J, Gao N, Qin Y Nat Struct Mol Biol. 2016 Feb;23(2):125-31. doi: 10.1038/nsmb.3160. Epub 2016 Jan, 25. PMID:26809121^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.