RNA Therapeutics Institute; Department of Biochemistry and Molecular Pharmacology
Biochemistry | Biophysics | Enzymes and Coenzymes | Molecular Biology | Nucleic Acids, Nucleotides, and Nucleosides | Structural Biology | Viruses
Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Forster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape the ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation.
E. coli, chromosomes, gene expression, molecular biophysics, structural biology
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© 2020, Bao et al. This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
DOI of Published Version
Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. Elife. 2020 May 19;9:e55799. doi: 10.7554/eLife.55799. Epub ahead of print. PMID: 32427100. Link to article on publisher's site
Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. (2020). mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. Open Access Publications by UMMS Authors. https://doi.org/10.7554/eLife.55799. Retrieved from https://escholarship.umassmed.edu/oapubs/4240
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