Publication details
Structural Basis for Polyproline-Mediated Ribosome Stalling and Rescue by the Translation Elongation Factor EF-P
| Authors | |
|---|---|
| Year of publication | 2017 |
| Type | Article in Periodical |
| Magazine / Source | Molecular Cell |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.sciencedirect.com/science/article/pii/S109727651730789X?via%3Dihub |
| Doi | http://dx.doi.org/10.1016/j.molcel.2017.10.014 |
| Keywords | PEPTIDE-BOND FORMATION; AMINOACYL-TRANSFER-RNA; MOLECULAR-DYNAMICS; PROTEIN-SYNTHESIS; 70S RIBOSOME; CRYO-EM; CRYSTAL-STRUCTURE; PROLINE RESIDUES; FACTOR EIF5A; MECHANISM |
| Attached files | |
| Description | Ribosomes synthesizing proteins containing consecutive proline residues become stalled and require rescue via the action of uniquely modified translation elongation factors, EF-P in bacteria, or archaeal/eukaryotic a/eIF5A. To date, no structures exist of EF-P or eIF5A in complex with translating ribosomes stalled at polyproline stretches, and thus structural insight into how EF-P/eIF5A rescue these arrested ribosomes has been lacking. Here we present cryo-EM structures of ribosomes stalled on proline stretches, without and with modified EF-P. The structures suggest that the favored conformation of the polyproline-containing nascent chain is incompatible with the peptide exit tunnel of the ribosome and leads to destabilization of the peptidyltRNA. Binding of EF-P stabilizes the P-site tRNA, particularly via interactions between its modification and the CCA end, thereby enforcing an alternative conformation of the polyproline-containing nascent chain, which allows a favorable substrate geometry for peptide bond formation. |
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