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Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content
The four-cysteine zinc finger motif of the bacterial RNA polymerase regulator DksA is essential for protein structure, canonical control of the stringent response to nutritional limitation, and thiol-based sensing of oxidative and nitrosative stress. This interdependent relationship has limited our...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4850274/ https://www.ncbi.nlm.nih.gov/pubmed/27094335 http://dx.doi.org/10.1128/mBio.02161-15 |
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author | Crawford, Matthew A. Tapscott, Timothy Fitzsimmons, Liam F. Liu, Lin Reyes, Aníbal M. Libby, Stephen J. Trujillo, Madia Fang, Ferric C. Radi, Rafael Vázquez-Torres, Andrés |
author_facet | Crawford, Matthew A. Tapscott, Timothy Fitzsimmons, Liam F. Liu, Lin Reyes, Aníbal M. Libby, Stephen J. Trujillo, Madia Fang, Ferric C. Radi, Rafael Vázquez-Torres, Andrés |
author_sort | Crawford, Matthew A. |
collection | PubMed |
description | The four-cysteine zinc finger motif of the bacterial RNA polymerase regulator DksA is essential for protein structure, canonical control of the stringent response to nutritional limitation, and thiol-based sensing of oxidative and nitrosative stress. This interdependent relationship has limited our understanding of DksA-mediated functions in bacterial pathogenesis. Here, we have addressed this challenge by complementing ΔdksA Salmonella with Pseudomonas aeruginosa dksA paralogues that encode proteins differing in cysteine and zinc content. We find that four-cysteine, zinc-bound (C4) and two-cysteine, zinc-free (C2) DksA proteins are able to mediate appropriate stringent control in Salmonella and that thiol-based sensing of reactive species is conserved among C2 and C4 orthologues. However, variations in cysteine and zinc content determine the threshold at which individual DksA proteins sense and respond to reactive species. In particular, zinc acts as an antioxidant, dampening cysteine reactivity and raising the threshold of posttranslational thiol modification with reactive species. Consequently, C2 DksA triggers transcriptional responses in Salmonella at levels of oxidative or nitrosative stress normally tolerated by Salmonella expressing C4 orthologues. Inappropriate transcriptional regulation by C2 DksA increases the susceptibility of Salmonella to the antimicrobial effects of hydrogen peroxide and nitric oxide, and attenuates virulence in macrophages and mice. Our findings suggest that the redox-active sensory function of DksA proteins is finely tuned to optimize bacterial fitness according to the levels of oxidative and nitrosative stress encountered by bacterial species in their natural and host environments. |
format | Online Article Text |
id | pubmed-4850274 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-48502742016-05-06 Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content Crawford, Matthew A. Tapscott, Timothy Fitzsimmons, Liam F. Liu, Lin Reyes, Aníbal M. Libby, Stephen J. Trujillo, Madia Fang, Ferric C. Radi, Rafael Vázquez-Torres, Andrés mBio Research Article The four-cysteine zinc finger motif of the bacterial RNA polymerase regulator DksA is essential for protein structure, canonical control of the stringent response to nutritional limitation, and thiol-based sensing of oxidative and nitrosative stress. This interdependent relationship has limited our understanding of DksA-mediated functions in bacterial pathogenesis. Here, we have addressed this challenge by complementing ΔdksA Salmonella with Pseudomonas aeruginosa dksA paralogues that encode proteins differing in cysteine and zinc content. We find that four-cysteine, zinc-bound (C4) and two-cysteine, zinc-free (C2) DksA proteins are able to mediate appropriate stringent control in Salmonella and that thiol-based sensing of reactive species is conserved among C2 and C4 orthologues. However, variations in cysteine and zinc content determine the threshold at which individual DksA proteins sense and respond to reactive species. In particular, zinc acts as an antioxidant, dampening cysteine reactivity and raising the threshold of posttranslational thiol modification with reactive species. Consequently, C2 DksA triggers transcriptional responses in Salmonella at levels of oxidative or nitrosative stress normally tolerated by Salmonella expressing C4 orthologues. Inappropriate transcriptional regulation by C2 DksA increases the susceptibility of Salmonella to the antimicrobial effects of hydrogen peroxide and nitric oxide, and attenuates virulence in macrophages and mice. Our findings suggest that the redox-active sensory function of DksA proteins is finely tuned to optimize bacterial fitness according to the levels of oxidative and nitrosative stress encountered by bacterial species in their natural and host environments. American Society for Microbiology 2016-04-19 /pmc/articles/PMC4850274/ /pubmed/27094335 http://dx.doi.org/10.1128/mBio.02161-15 Text en Copyright © 2016 Crawford et al. http://creativecommons.org/licenses/by-nc-sa/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-ShareAlike 3.0 Unported license (http://creativecommons.org/licenses/by-nc-sa/3.0/) , which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Crawford, Matthew A. Tapscott, Timothy Fitzsimmons, Liam F. Liu, Lin Reyes, Aníbal M. Libby, Stephen J. Trujillo, Madia Fang, Ferric C. Radi, Rafael Vázquez-Torres, Andrés Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title | Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title_full | Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title_fullStr | Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title_full_unstemmed | Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title_short | Redox-Active Sensing by Bacterial DksA Transcription Factors Is Determined by Cysteine and Zinc Content |
title_sort | redox-active sensing by bacterial dksa transcription factors is determined by cysteine and zinc content |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4850274/ https://www.ncbi.nlm.nih.gov/pubmed/27094335 http://dx.doi.org/10.1128/mBio.02161-15 |
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