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-Structure paper
Title | EF4 disengages the peptidyl-tRNA CCA end and facilitates back-translocation on the 70S ribosome. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 23, Issue 2, Page 125-131, Year 2016 |
Publish date | Jan 25, 2016 |
Authors | Dejiu Zhang / Kaige Yan / Guangqiao Liu / Guangtao Song / Jiejian Luo / Yi Shi / Erchao Cheng / Shan Wu / Taijiao Jiang / Jizhong Lou / Ning Gao / Yan Qin / |
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- ...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. |
External links | Nat Struct Mol Biol / PubMed:26809121 |
Methods | EM (single particle) |
Resolution | 3.2 - 3.7 Å |
Structure data | |
Chemicals | ChemComp-PHE: ChemComp-GNP: ChemComp-MG: |
Source |
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Keywords | RIBOSOME / ribosome elongation / GTPase EF4 / tRNA back-translocation / P-loop |