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How the initiating ribosome copes with ppGpp to translate mRNAs

During host colonization, bacteria use the alarmones (p)ppGpp to reshape their proteome by acting pleiotropically on DNA, RNA, and protein synthesis. Here, we elucidate how the initiating ribosome senses the cellular pool of guanosine nucleotides and regulates the progression towards protein synthes...

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Autores principales: Vinogradova, Daria S., Zegarra, Victor, Maksimova, Elena, Nakamoto, Jose Alberto, Kasatsky, Pavel, Paleskava, Alena, Konevega, Andrey L., Milón, Pohl
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7010297/
https://www.ncbi.nlm.nih.gov/pubmed/31995552
http://dx.doi.org/10.1371/journal.pbio.3000593
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author Vinogradova, Daria S.
Zegarra, Victor
Maksimova, Elena
Nakamoto, Jose Alberto
Kasatsky, Pavel
Paleskava, Alena
Konevega, Andrey L.
Milón, Pohl
author_facet Vinogradova, Daria S.
Zegarra, Victor
Maksimova, Elena
Nakamoto, Jose Alberto
Kasatsky, Pavel
Paleskava, Alena
Konevega, Andrey L.
Milón, Pohl
author_sort Vinogradova, Daria S.
collection PubMed
description During host colonization, bacteria use the alarmones (p)ppGpp to reshape their proteome by acting pleiotropically on DNA, RNA, and protein synthesis. Here, we elucidate how the initiating ribosome senses the cellular pool of guanosine nucleotides and regulates the progression towards protein synthesis. Our results show that the affinity of guanosine triphosphate (GTP) and the inhibitory concentration of ppGpp for the 30S-bound initiation factor IF2 vary depending on the programmed mRNA. The TufA mRNA enhanced GTP affinity for 30S complexes, resulting in improved ppGpp tolerance and allowing efficient protein synthesis. Conversely, the InfA mRNA allowed ppGpp to compete with GTP for IF2, thus stalling 30S complexes. Structural modeling and biochemical analysis of the TufA mRNA unveiled a structured enhancer of translation initiation (SETI) composed of two consecutive hairpins proximal to the translation initiation region (TIR) that largely account for ppGpp tolerance under physiological concentrations of guanosine nucleotides. Furthermore, our results show that the mechanism enhancing ppGpp tolerance is not restricted to the TufA mRNA, as similar ppGpp tolerance was found for the SETI-containing Rnr mRNA. Finally, we show that IF2 can use pppGpp to promote the formation of 30S initiation complexes (ICs), albeit requiring higher factor concentration and resulting in slower transitions to translation elongation. Altogether, our data unveil a novel regulatory mechanism at the onset of protein synthesis that tolerates physiological concentrations of ppGpp and that bacteria can exploit to modulate their proteome as a function of the nutritional shift happening during stringent response and infection.
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spelling pubmed-70102972020-02-21 How the initiating ribosome copes with ppGpp to translate mRNAs Vinogradova, Daria S. Zegarra, Victor Maksimova, Elena Nakamoto, Jose Alberto Kasatsky, Pavel Paleskava, Alena Konevega, Andrey L. Milón, Pohl PLoS Biol Research Article During host colonization, bacteria use the alarmones (p)ppGpp to reshape their proteome by acting pleiotropically on DNA, RNA, and protein synthesis. Here, we elucidate how the initiating ribosome senses the cellular pool of guanosine nucleotides and regulates the progression towards protein synthesis. Our results show that the affinity of guanosine triphosphate (GTP) and the inhibitory concentration of ppGpp for the 30S-bound initiation factor IF2 vary depending on the programmed mRNA. The TufA mRNA enhanced GTP affinity for 30S complexes, resulting in improved ppGpp tolerance and allowing efficient protein synthesis. Conversely, the InfA mRNA allowed ppGpp to compete with GTP for IF2, thus stalling 30S complexes. Structural modeling and biochemical analysis of the TufA mRNA unveiled a structured enhancer of translation initiation (SETI) composed of two consecutive hairpins proximal to the translation initiation region (TIR) that largely account for ppGpp tolerance under physiological concentrations of guanosine nucleotides. Furthermore, our results show that the mechanism enhancing ppGpp tolerance is not restricted to the TufA mRNA, as similar ppGpp tolerance was found for the SETI-containing Rnr mRNA. Finally, we show that IF2 can use pppGpp to promote the formation of 30S initiation complexes (ICs), albeit requiring higher factor concentration and resulting in slower transitions to translation elongation. Altogether, our data unveil a novel regulatory mechanism at the onset of protein synthesis that tolerates physiological concentrations of ppGpp and that bacteria can exploit to modulate their proteome as a function of the nutritional shift happening during stringent response and infection. Public Library of Science 2020-01-29 /pmc/articles/PMC7010297/ /pubmed/31995552 http://dx.doi.org/10.1371/journal.pbio.3000593 Text en © 2020 Vinogradova et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Vinogradova, Daria S.
Zegarra, Victor
Maksimova, Elena
Nakamoto, Jose Alberto
Kasatsky, Pavel
Paleskava, Alena
Konevega, Andrey L.
Milón, Pohl
How the initiating ribosome copes with ppGpp to translate mRNAs
title How the initiating ribosome copes with ppGpp to translate mRNAs
title_full How the initiating ribosome copes with ppGpp to translate mRNAs
title_fullStr How the initiating ribosome copes with ppGpp to translate mRNAs
title_full_unstemmed How the initiating ribosome copes with ppGpp to translate mRNAs
title_short How the initiating ribosome copes with ppGpp to translate mRNAs
title_sort how the initiating ribosome copes with ppgpp to translate mrnas
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7010297/
https://www.ncbi.nlm.nih.gov/pubmed/31995552
http://dx.doi.org/10.1371/journal.pbio.3000593
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