EMD-3490

Single-particle
3.06 Å
EMD-3490 Deposition: 13/11/2016
Map released: 14/12/2016
Last modified: 24/04/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-3490

Structure of ArfA(A18T) and RF2 bound to the 70S ribosome (pre-accommodated state)

EMD-3490

Single-particle
3.06 Å
EMD-3490 Deposition: 13/11/2016
Map released: 14/12/2016
Last modified: 24/04/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Escherichia coli
Sample: Structure of ArfA(A18T) and RF2 bound to the 70S ribosome (pre-accommodated state)
Fitted models: 5mdw (Avg. Q-score: 0.531)

Deposition Authors: James NR , Brown A
Translational termination without a stop codon.
James NR , Brown A , Gordiyenko Y, Ramakrishnan V
(2016) Science , 354 , 1437 - 1440
PUBMED: 27934701
DOI: doi:10.1126/science.aai9127
ISSN: 1095-9203
ASTM: SCIEAS
Abstract:
Ribosomes stall when they encounter the end of messenger RNA (mRNA) without an in-frame stop codon. In bacteria, these "nonstop" complexes can be rescued by alternative ribosome-rescue factor A (ArfA). We used electron cryomicroscopy to determine structures of ArfA bound to the ribosome with 3'-truncated mRNA, at resolutions ranging from 3.0 to 3.4 angstroms. ArfA binds within the ribosomal mRNA channel and substitutes for the absent stop codon in the A site by specifically recruiting release factor 2 (RF2), initially in a compact preaccommodated state. A similar conformation of RF2 may occur on stop codons, suggesting a general mechanism for release-factor-mediated translational termination in which a conformational switch leads to peptide release only when the appropriate signal is present in the A site.