Cryo-EM of Ribosomal 80S Complexes with Termination Factors Reveals the Translocated Cricket Paralysis Virus IRES
| Autor: | Thorsten Mielke, Margarita Muhs, Tatyana V. Pestova, T. Hilal, Karissa Y. Sanbonmatsu, Christian M. T. Spahn, Maxim A. Skabkin |
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| Rok vydání: | 2015 |
| Předmět: |
Models
Molecular Molecular Sequence Data Molecular Conformation Ribosome Article RNA Transfer Eukaryotic initiation factor Initiation factor RNA Messenger Eukaryotic Initiation Factors Cricket paralysis virus Molecular Biology biology Cryoelectron Microscopy fungi Cell Biology biology.organism_classification Molecular biology Cell biology Internal ribosome entry site A-site Protein Biosynthesis Transfer RNA Dicistroviridae Nucleic Acid Conformation RNA Viral ATP-Binding Cassette Transporters Eukaryotic Ribosome Ribosomes Peptide Termination Factors |
| Zdroj: | Molecular Cell |
| ISSN: | 1097-2765 |
| DOI: | 10.1016/j.molcel.2014.12.016 |
| Popis: | The cricket paralysis virus (CrPV) uses an internal ribosomal entry site (IRES) to hijack the ribosome. In a remarkable RNA-based mechanism involving neither initiation factor nor initiator tRNA, the CrPV IRES jumpstarts translation in the elongation phase from the ribosomal A site. Here, we present cryoelectron microscopy (cryo-EM) maps of 80S⋅CrPV-STOP ⋅ eRF1 ⋅ eRF3 ⋅ GMPPNP and 80S⋅CrPV-STOP ⋅ eRF1 complexes, revealing a previously unseen binding state of the IRES and directly rationalizing that an eEF2-dependent translocation of the IRES is required to allow the first A-site occupation. During this unusual translocation event, the IRES undergoes a pronounced conformational change to a more stretched conformation. At the same time, our structural analysis provides information about the binding modes of eRF1 ⋅ eRF3 ⋅ GMPPNP and eRF1 in a minimal system. It shows that neither eRF3 nor ABCE1 are required for the active conformation of eRF1 at the intersection between eukaryotic termination and recycling. |
| Databáze: | OpenAIRE |
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