Summary information and primary citation
- PDB-id
-
4d61;
DSSR-derived features in text and
JSON formats
- Class
- ribosome
- Method
- cryo-EM (9.0 Å)
- Summary
- cryo-EM structures of ribosomal 80s complexes with
termination factors and cricket paralysis virus ires reveal
the ires in the translocated state
- Reference
-
Muhs M, Hilal T, Mielke T, Skabkin MA, Sanbonmatsu KY,
Pestova TV, Spahn CMT (2015): "Cryo-Em of
Ribosomal 80S Complexes with Termination Factors Reveals
the Translocated Cricket Paralysis Virus Ires."
Mol.Cell, 57, 422. doi:
10.1016/J.MOLCEL.2014.12.016.
- 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.
