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Proc Natl Acad Sci U S A. 2018 Jan 16;115(3):E382-E389. doi: 10.1073/pnas.1714554115. Epub 2018 Jan 3.

Atomic mutagenesis of stop codon nucleotides reveals the chemical prerequisites for release factor-mediated peptide release.

Author information

1
Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria.
2
Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria.
3
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314.
4
Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria.
5
Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland.
6
Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; matthias.erlacher@i-med.ac.at.

Abstract

Termination of protein synthesis is triggered by the recognition of a stop codon at the ribosomal A site and is mediated by class I release factors (RFs). Whereas in bacteria, RF1 and RF2 promote termination at UAA/UAG and UAA/UGA stop codons, respectively, eukaryotes only depend on one RF (eRF1) to initiate peptide release at all three stop codons. Based on several structural as well as biochemical studies, interactions between mRNA, tRNA, and rRNA have been proposed to be required for stop codon recognition. In this study, the influence of these interactions was investigated by using chemically modified stop codons. Single functional groups within stop codon nucleotides were substituted to weaken or completely eliminate specific interactions between the respective mRNA and RFs. Our findings provide detailed insight into the recognition mode of bacterial and eukaryotic RFs, thereby revealing the chemical groups of nucleotides that define the identity of stop codons and provide the means to discriminate against noncognate stop codons or UGG sense codons.

KEYWORDS:

mRNA modification; peptide release; release factor; ribosome; translation

PMID:
29298914
PMCID:
PMC5776981
DOI:
10.1073/pnas.1714554115
[Indexed for MEDLINE]
Free PMC Article

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