Download MendeleyEF4 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.(2016) Nat Struct Mol Biol 23: 125-131
- PubMed: 26809121 Search on PubMed
- DOI: https://doi.org/10.1038/nsmb.3160
- Primary Citation Related Structures:
3JCD, 3JCE - PubMed Abstract:
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-Å 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.
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
Organizational Affiliation:
