5mdv
From Proteopedia
Structure of ArfA and RF2 bound to the 70S ribosome (accommodated state)
Structural highlights
FunctionARFA_ECOLI Rescues the ribosomes stalled at the 3' end of non-stop mRNAs. May induce hydrolysis of the ribosome-bound peptidyl-tRNA. This activity is crucial when the stalled ribosome cannot be rescued by the SsrA(tmRNA)-SmpB quality control system.[1] [2] Publication Abstract from PubMedRibosomes 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. Translational termination without a stop codon.,James NR, Brown A, Gordiyenko Y, Ramakrishnan V Science. 2016 Dec 16;354(6318):1437-1440. Epub 2016 Dec 1. PMID:27934701[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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