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Translational termination without a stop codon.

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.

SUBMITTER: James NR

PROVIDER: S-EPMC5351859 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Translational termination without a stop codon.

James Nathan R NR Brown Alan A Gordiyenko Yuliya Y Ramakrishnan V V

Science (New York, N.Y.) 20161201 6318

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 fa ...[more]

PMID: 27934701

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Translational termination efficiency in mammals is influenced by the base following the stop codon.

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Project description:This SuperSeries is composed of the SubSeries listed below.

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Partitioning between recoding and termination at a stop codon-selenocysteine insertion sequence.

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