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Srour B, Gervason S, Hoock MH, Monfort B, Want K, Larkem D, Trabelsi N, Landrot G, Zitolo A, Fonda E, Etienne E, Gerbaud G, Müller CS, Oltmanns J, Gordon JB, Yadav V, Kleczewska M, Jelen M, Toledano MB, Dutkiewicz R, Goldberg DP, Schünemann V, Guigliarelli B, Burlat B, Sizun C, D'Autréaux B. Iron Insertion at the Assembly Site of the ISCU Scaffold Protein Is a Conserved Process Initiating Fe-S Cluster Biosynthesis. J Am Chem Soc 2022; 144:17496-17515. [PMID: 36121382 PMCID: PMC10163866 DOI: 10.1021/jacs.2c06338] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron-sulfur (Fe-S) clusters are prosthetic groups of proteins biosynthesized on scaffold proteins by highly conserved multi-protein machineries. Biosynthesis of Fe-S clusters into the ISCU scaffold protein is initiated by ferrous iron insertion, followed by sulfur acquisition, via a still elusive mechanism. Notably, whether iron initially binds to the ISCU cysteine-rich assembly site or to a cysteine-less auxiliary site via N/O ligands remains unclear. We show here by SEC, circular dichroism (CD), and Mössbauer spectroscopies that iron binds to the assembly site of the monomeric form of prokaryotic and eukaryotic ISCU proteins via either one or two cysteines, referred to the 1-Cys and 2-Cys forms, respectively. The latter predominated at pH 8.0 and correlated with the Fe-S cluster assembly activity, whereas the former increased at a more acidic pH, together with free iron, suggesting that it constitutes an intermediate of the iron insertion process. Iron not binding to the assembly site was non-specifically bound to the aggregated ISCU, ruling out the existence of a structurally defined auxiliary site in ISCU. Characterization of the 2-Cys form by site-directed mutagenesis, CD, NMR, X-ray absorption, Mössbauer, and electron paramagnetic resonance spectroscopies showed that the iron center is coordinated by four strictly conserved amino acids of the assembly site, Cys35, Asp37, Cys61, and His103, in a tetrahedral geometry. The sulfur receptor Cys104 was at a very close distance and apparently bound to the iron center when His103 was missing, which may enable iron-dependent sulfur acquisition. Altogether, these data provide the structural basis to elucidate the Fe-S cluster assembly process and establish that the initiation of Fe-S cluster biosynthesis by insertion of a ferrous iron in the assembly site of ISCU is a conserved mechanism.
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Affiliation(s)
- Batoul Srour
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Sylvain Gervason
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Maren Hellen Hoock
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Beata Monfort
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Kristian Want
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Djabir Larkem
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Nadine Trabelsi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gautier Landrot
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Andrea Zitolo
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Emiliano Fonda
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48 Saint Aubin 91192 Gif-Sur-Yvette, France
| | - Emilien Etienne
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Guillaume Gerbaud
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Christina Sophia Müller
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Jonathan Oltmanns
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Jesse B Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Vishal Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Malgorzata Kleczewska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Marcin Jelen
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Michel B Toledano
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Rafal Dutkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Volker Schünemann
- Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany
| | - Bruno Guigliarelli
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Bénédicte Burlat
- Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Christina Sizun
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris Saclay, Avenue de La Terrasse, 91190 Gif-sur-Yvette, France
| | - Benoit D'Autréaux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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Redox-Mediated Inactivation of the Transcriptional Repressor RcrR is Responsible for Uropathogenic Escherichia coli's Increased Resistance to Reactive Chlorine Species. mBio 2022; 13:e0192622. [PMID: 36073817 PMCID: PMC9600549 DOI: 10.1128/mbio.01926-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The ability to overcome stressful environments is critical for pathogen survival in the host. One challenge for bacteria is the exposure to reactive chlorine species (RCS), which are generated by innate immune cells as a critical part of the oxidative burst. Hypochlorous acid (HOCl) is the most potent antimicrobial RCS and is associated with extensive macromolecular damage in the phagocytized pathogen. However, bacteria have evolved defense strategies to alleviate the effects of HOCl-mediated damage. Among these are RCS-sensing transcriptional regulators that control the expression of HOCl-protective genes under non-stress and HOCl stress. Uropathogenic Escherichia coli (UPEC), the major causative agent of urinary tract infections (UTIs), is particularly exposed to infiltrating neutrophils during pathogenesis; however, their responses to and defenses from HOCl are still completely unexplored. Here, we present evidence that UPEC strains tolerate higher levels of HOCl and are better protected from neutrophil-mediated killing compared with other E. coli. Transcriptomic analysis of HOCl-stressed UPEC revealed the upregulation of an operon consisting of three genes, one of which encodes the transcriptional regulator RcrR. We identified RcrR as a HOCl-responsive transcriptional repressor, which, under non-stress conditions, is bound to the operator and represses the expression of its target genes. During HOCl exposure, however, the repressor forms reversible intermolecular disulfide bonds and dissociates from the DNA resulting in the derepression of the operon. Deletion of one of the target genes renders UPEC significantly more susceptible to HOCl and phagocytosis indicating that the HOCl-mediated induction of the regulon plays a major role for UPEC’s HOCl resistance.
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Gonzaga de França Lopes L, Gouveia Júnior FS, Karine Medeiros Holanda A, Maria Moreira de Carvalho I, Longhinotti E, Paulo TF, Abreu DS, Bernhardt PV, Gilles-Gonzalez MA, Cirino Nogueira Diógenes I, Henrique Silva Sousa E. Bioinorganic systems responsive to the diatomic gases O2, NO, and CO: From biological sensors to therapy. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Arora DP, Hossain S, Xu Y, Boon EM. Nitric Oxide Regulation of Bacterial Biofilms. Biochemistry 2015; 54:3717-28. [PMID: 25996573 DOI: 10.1021/bi501476n] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Biofilms are surface-associated, multicellular communities of bacteria. Once established, they are extremely difficult to eradicate by antimicrobial treatment. It has been demonstrated in many species that biofilm formation may be regulated by the diatomic signaling molecule nitric oxide (NO). Although this is still a relatively new area of research, we review here the literature reporting an effect of NO on bacterial biofilm formation, emphasizing dose-dependent responses to NO concentrations when possible. Where it has been investigated, the underlying NO sensors or signaling pathways are also discussed. Most of the examples of NO-mediated biofilm regulation have been documented with exogenously applied NO, but we also survey possible natural sources of NO in biofilm regulation, including endogenously generated NO. Finally, because of the apparent broad-spectrum, antibiofilm effects of NO, NO-releasing materials and prodrugs have also been explored in this minireview.
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Affiliation(s)
- Dhruv P Arora
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Sajjad Hossain
- §Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Yueming Xu
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Elizabeth M Boon
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.,§Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, New York 11794-3400, United States
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Busch AW, Montgomery BL. Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response. Redox Biol 2015; 4:260-71. [PMID: 25618582 PMCID: PMC4315935 DOI: 10.1016/j.redox.2015.01.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 01/01/2023] Open
Abstract
Tetrapyrroles are involved in light harvesting and light perception, electron-transfer reactions, and as co-factors for key enzymes and sensory proteins. Under conditions in which cells exhibit stress-induced imbalances of photosynthetic reactions, or light absorption exceeds the ability of the cell to use photoexcitation energy in synthesis reactions, redox imbalance can occur in photosynthetic cells. Such conditions can lead to the generation of reactive oxygen species (ROS) associated with alterations in tetrapyrrole homeostasis. ROS accumulation can result in cellular damage and detrimental effects on organismal fitness, or ROS molecules can serve as signals to induce a protective or damage-mitigating oxidative stress signaling response in cells. Induced oxidative stress responses include tetrapyrrole-dependent and -independent mechanisms for mitigating ROS generation and/or accumulation. Thus, tetrapyrroles can be contributors to oxidative stress, but are also essential in the oxidative stress response to protect cells by contributing to detoxification of ROS. In this review, we highlight the interconnection and interdependence of tetrapyrrole metabolism with the occurrence of oxidative stress and protective oxidative stress signaling responses in photosynthetic organisms. Tetrapyrroles are involved in light sensing and oxidative stress mitigation. Reactive oxygen species (ROS) can form upon light exposure of free tetrapyrroles. Tetrapyrrole homeostasis must be tightly regulated to avoid oxidative stress. ROS can result in cellular damage or oxidative stress signaling in cells.
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Fillat MF. The FUR (ferric uptake regulator) superfamily: diversity and versatility of key transcriptional regulators. Arch Biochem Biophys 2014; 546:41-52. [PMID: 24513162 DOI: 10.1016/j.abb.2014.01.029] [Citation(s) in RCA: 214] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/27/2014] [Accepted: 01/31/2014] [Indexed: 11/17/2022]
Abstract
Control of metal homeostasis is essential for life in all kingdoms. In most prokaryotic organisms the FUR (ferric uptake regulator) family of transcriptional regulators is involved in the regulation of iron and zinc metabolism through control by Fur and Zur proteins. A third member of this family, the peroxide-stress response PerR, is present in most Gram-positives, establishing a tight functional interaction with the global regulator Fur. These proteins play a pivotal role for microbial survival under adverse conditions and in the expression of virulence in most pathogens. In this paper we present the current state of the art in the knowledge of the FUR family, including those members only present in more reduced numbers of bacteria, namely Mur, Nur and Irr. The huge amount of work done in the two last decades shows that FUR proteins present considerable diversity in their regulatory mechanisms and interesting structural differences. However, much work needs to be done to obtain a more complete picture of this family, especially in connection with the roles of some members as gas and redox sensors as well as to fully characterize their participation in bacterial adaptative responses.
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Affiliation(s)
- María F Fillat
- Department of Biochemistry and Molecular and Cell Biology, Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Pedro Cerbuna, 12, 50009 Zaragoza, Spain.
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Henard CA, Tapscott T, Crawford MA, Husain M, Doulias PT, Porwollik S, Liu L, McClelland M, Ischiropoulos H, Vázquez-Torres A. The 4-cysteine zinc-finger motif of the RNA polymerase regulator DksA serves as a thiol switch for sensing oxidative and nitrosative stress. Mol Microbiol 2014; 91:790-804. [PMID: 24354846 DOI: 10.1111/mmi.12498] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2013] [Indexed: 02/03/2023]
Abstract
We show that thiols in the 4-cysteine zinc-finger motif of DksA, an RNA polymerase accessory protein known to regulate the stringent response, sense oxidative and nitrosative stress. Hydrogen peroxide- or nitric oxide (NO)-mediated modifications of thiols in the DksA 4-cysteine zinc-finger motif release the metal cofactor and drive reversible changes in the α-helicity of the protein. Wild-type and relA spoT mutant Salmonella, but not isogenic dksA-deficient bacteria, experience the downregulation of r-protein and amino acid transport expression after NO treatment, suggesting that DksA can regulate gene expression in response to NO congeners independently of the ppGpp alarmone. Oxidative stress enhances the DksA-dependent repression of rpsM, while preventing the activation of livJ and hisG gene transcription that is supported by reduced, zinc-bound DksA. The inhibitory effects of oxidized DksA on transcription are reversible with dithiothreitol. Our investigations indicate that sensing of reactive species by DksA redox active thiols fine-tunes the expression of translational machinery and amino acid assimilation and biosynthesis in accord with the metabolic stress imposed by oxidative and nitrosative stress. Given the conservation of Cys(114) , and neighbouring hydrophobic and charged amino acids in DksA orthologues, phylogenetically diverse microorganisms may use the DksA thiol switch to regulate transcriptional responses to oxidative and nitrosative stress.
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Affiliation(s)
- Calvin A Henard
- Department of Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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8
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Ferric uptake regulator-dependent antinitrosative defenses in Salmonella enterica serovar Typhimurium pathogenesis. Infect Immun 2013; 82:333-40. [PMID: 24166960 DOI: 10.1128/iai.01201-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Herein we report an important role for the ferric uptake regulator (Fur) in the resistance of Salmonella enterica serovar Typhimurium to the reactive nitrogen species produced by inducible nitric oxide (NO) synthase in an NRAMP1(r) murine model of acute systemic infection. The expression of fur protected Salmonella grown under normoxic and hypoxic conditions against the bacteriostatic activity of NO. The hypersusceptibility of fur-deficient Salmonella to the cytotoxic actions of NO coincides with a marked repression of respiratory activity and the reduced ability of the bacteria to detoxify NO. A fur mutant Salmonella strain contained reduced levels of the terminal quinol oxidases of the electron transport chain. Addition of the heme precursor δ-aminolevulinic acid restored the cytochrome content, respiratory activity, NO consumption, and wild-type growth in bacteria undergoing nitrosative stress. The innate antinitrosative defenses regulated by Fur added to the adaptive response associated with the NO-detoxifying activity of the flavohemoprotein Hmp. Our investigations indicate that, in addition to playing a critical role in iron homeostasis, Fur is an important antinitrosative determinant of Salmonella pathogenesis.
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Parker BW, Schwessinger EA, Jakob U, Gray MJ. The RclR protein is a reactive chlorine-specific transcription factor in Escherichia coli. J Biol Chem 2013; 288:32574-32584. [PMID: 24078635 DOI: 10.1074/jbc.m113.503516] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Reactive chlorine species (RCS) such as hypochlorous acid are powerful antimicrobial oxidants. Used extensively for disinfection in household and industrial settings (i.e. as bleach), RCS are also naturally generated in high quantities during the innate immune response. Bacterial responses to RCS are complex and differ substantially from the well characterized responses to other physiologically relevant oxidants, like peroxide or superoxide. Several RCS-sensitive transcription factors have been identified in bacteria, but most of them respond to multiple stressors whose damaging effects overlap with those of RCS, including reactive oxygen species and electrophiles. We have now used in vivo genetic and in vitro biochemical methods to identify and demonstrate that Escherichia coli RclR (formerly YkgD) is a redox-regulated transcriptional activator of the AraC family, whose highly conserved cysteine residues are specifically sensitive to oxidation by RCS. Oxidation of these cysteines leads to strong, highly specific activation of expression of genes required for survival of RCS stress. These results demonstrate the existence of a widely conserved bacterial regulon devoted specifically to RCS resistance.
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Affiliation(s)
- Benjamin W Parker
- From the Department of Molecular, Cellular, and Developmental Biology
| | | | - Ursula Jakob
- From the Department of Molecular, Cellular, and Developmental Biology; the Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109.
| | - Michael J Gray
- From the Department of Molecular, Cellular, and Developmental Biology.
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Tinajero-Trejo M, Jesse HE, Poole RK. Gasotransmitters, poisons, and antimicrobials: it's a gas, gas, gas! F1000PRIME REPORTS 2013; 5:28. [PMID: 23967379 PMCID: PMC3732073 DOI: 10.12703/p5-28] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We review recent examples of the burgeoning literature on three gases that have major impacts in biology and microbiology. NO, CO and H2S are now co-classified as endogenous gasotransmitters with profound effects on mammalian physiology and, potentially, major implications in therapeutic applications. All are well known to be toxic yet, at tiny concentrations in human and cell biology, play key signalling and regulatory functions. All may also be endogenously generated in microbes. NO and H2S share the property of being biochemically detoxified, yet are beneficial in resisting the bactericidal properties of antibiotics. The mechanism underlying this protection is currently under debate. CO, in contrast, is not readily removed; mounting evidence shows that CO, and especially organic donor compounds that release the gas in biological environments, are themselves effective, novel antimicrobial agents.
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12
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Abstract
Hypochlorous acid (HOCl), the active ingredient of household bleach, is the most common disinfectant in medical, industrial, and domestic use and plays an important role in microbial killing in the innate immune system. Given the critical importance of the antimicrobial properties of chlorine to public health, it is surprising how little is known about the ways in which bacteria sense and respond to reactive chlorine species (RCS). Although the literature on bacterial responses to reactive oxygen species (ROS) is enormous, work addressing bacterial responses to RCS has begun only recently. Transcriptomic and proteomic studies now provide new insights into how bacteria mount defenses against this important class of antimicrobial compounds. In this review, we summarize the current knowledge, emphasizing the overlaps between RCS stress responses and other more well-characterized bacterial defense systems, and identify outstanding questions that represent productive avenues for future research.
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Affiliation(s)
- Michael J Gray
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048; , ,
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Gray MJ, Wholey WY, Parker BW, Kim M, Jakob U. NemR is a bleach-sensing transcription factor. J Biol Chem 2013; 288:13789-98. [PMID: 23536188 DOI: 10.1074/jbc.m113.454421] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Little is known about how bacteria sense or respond to reactive chlorine species, such as bleach. RESULTS NemR is a redox-regulated transcription factor which senses bleach. CONCLUSION NemR controls expression of genes encoding electrophile detoxification enzymes, which increase bleach resistance. SIGNIFICANCE We demonstrate a bleach-sensing bacterial response system and a new mechanism contributing to bacterial bleach survival. Hypochlorous acid (HOCl), the active component of household bleach, also functions as a powerful antimicrobial during the innate immune response. Despite its widespread use, surprisingly little is known about how cells sense or respond to HOCl. We now demonstrate that Escherichia coli NemR is a redox-regulated transcriptional repressor, which uses the oxidation status of HOCl-sensitive cysteine residues to respond to bleach and related reactive chlorine species. NemR controls bleach-mediated expression of two enzymes required for detoxification of reactive electrophiles: glyoxalase I and N-ethylmaleimide reductase. Both enzymes contribute to bacterial bleach survival. These results provide evidence that bleach resistance relies on the capacity of organisms to specifically sense reactive chlorine species and respond with the up-regulation of enzymes dedicated to detoxification of methylglyoxal and other reactive electrophiles.
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Affiliation(s)
- Michael J Gray
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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