Download MendeleyCryo-Em of Ribosomal 80S Complexes with Termination Factors Reveals the Translocated Cricket Paralysis Virus Ires.
Muhs, M., Hilal, T., Mielke, T., Skabkin, M.A., Sanbonmatsu, K.Y., Pestova, T.V., Spahn, C.M.T.(2015) Mol Cell 57: 422
- PubMed: 25601755
- DOI: https://doi.org/10.1016/j.molcel.2014.12.016
- Primary Citation of Related Structures:
4D5L, 4D5N, 4D5Y, 4D61, 4D67 - PubMed Abstract:
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.
Organizational Affiliation:
Institut für Medizinische Physik und Biophysik, Charite - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
