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Yang X, Qian M, Wang Y, Qin Z, Luo M, Chen G, Yi C, Ma Y, Liu X, Liu Z. Thiol-Based Modification of MarR Protein VnrR Regulates Resistance Toward Nitrofuran in Vibrio cholerae By Promoting the Expression of a Novel Nitroreductase VnrA and of NO-Detoxifying Enzyme HmpA. Antioxid Redox Signal 2024; 40:926-942. [PMID: 37742113 DOI: 10.1089/ars.2022.0205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/25/2023]
Abstract
Aims: Epidemiological investigations have indicated low resistance toward nitrofuran in clinical isolates, suggesting its potential application in the treatment of multidrug-resistant bacteria. Therefore, it is valuable to explore the mechanism of bacterial resistance to nitrofuran. Results: Through phenotypic screening of ten multiple antibiotic resistance regulator (MarR) proteins in Vibrio cholerae, we discovered that the regulator VnrR (VCA1058) plays a crucial role in defending against nitrofuran, specifically furazolidone (FZ). Our findings demonstrate that VnrR responds to FZ metabolites, such as hydroxylamine, methylglyoxal, hydrogen peroxide (H2O2), β-hydroxyethylhydrazine. Notably, VnrR exhibits reversible responses to the addition of H2O2 through three cysteine residues (Cys180, Cys223, Cys247), leading to the derepression of its upstream gene, vnrA (vca1057). Gene vnrA encodes a novel nitroreductase, which directly contributes to the degradation of FZ. Our study reveals that V. cholerae metabolizes FZ via the vnrR-vnrA system and achieves resistance to FZ with the assistance of the classical reactive oxygen/nitrogen species scavenging pathway. Innovation and Conclusion: This study represents a significant advancement in understanding the antibiotic resistance mechanisms of V. cholerae and other pathogens. Our findings demonstrate that the MarR family regulator, VnrR, responds to the FZ metabolite H2O2, facilitating the degradation and detoxification of this antibiotic in a thiol-dependent manner. These insights not only enrich our knowledge of antibiotic resistance but also provide new perspectives for the control and prevention of multidrug-resistant bacteria.
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Affiliation(s)
- Xiaoman Yang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Mingjie Qian
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Wang
- Department of Microbiology and Infectious Disease Center, NHC Key Laboratory of Medical Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Zixin Qin
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Mei Luo
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Guozhong Chen
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Chunrong Yi
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yao Ma
- Research Institute of Tsinghua University in Shenzhen, Human Microecology and Healthcare R&D Centre, High-tech Industrial Park, Shenzhen, Guangdong, China
| | - Xiaoyun Liu
- Department of Microbiology and Infectious Disease Center, NHC Key Laboratory of Medical Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Zhi Liu
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Quach NT, Nguyen TTA, Vu THN, Nguyen TTN, Tran XK, Chu NH, Ta TTT, Chu HH, Phi QT. New insight into protective effect against oxidative stress and biosynthesis of exopolysaccharides produced by Lacticaseibacillus paracasei NC4 from fermented eggplant. Curr Genet 2024; 70:7. [PMID: 38743270 DOI: 10.1007/s00294-024-01292-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/16/2024]
Abstract
Fermented eggplant is a traditional fermented food, however lactic acid bacteria capable of producing exopolysaccharide (EPS) have not yet been exploited. The present study focused on the production and protective effects against oxidative stress of an EPS produced by Lacticaseibacillus paracasei NC4 (NC4-EPS), in addition to deciphering its genomic features and EPS biosynthesis pathway. Among 54 isolates tested, strain NC4 showed the highest EPS yield and antioxidant activity. The maximum EPS production (2.04 ± 0.11 g/L) was achieved by culturing in MRS medium containing 60 g/L sucrose at 37 °C for 48 h. Under 2 mM H2O2 stress, the survival of a yeast model Saccharomyces cerevisiae treated with 0.4 mg/mL NC4-EPS was 2.4-fold better than non-treated cells, which was in agreement with the catalase and superoxide dismutase activities measured from cell lysates. The complete genome of NC4 composed of a circular chromosome of 2,888,896 bp and 3 circular plasmids. The NC4 genome comprises more genes with annotated function in nitrogen metabolism, phosphorus metabolism, cell division and cell cycle, and iron acquisition and metabolism as compared to other reported L. paracasei. Of note, the eps gene cluster is not conserved across L. paracasei. Pathways of sugar metabolism for EPS biosynthesis were proposed for the first time, in which gdp pathway only present in few plant-derived bacteria was identified. These findings shed new light on the cell-protective activity and biosynthesis of EPS produced by L. paracasei, paving the way for future efforts to enhance yield and tailor-made EPS production for food and pharmaceutical industries.
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Affiliation(s)
- Ngoc Tung Quach
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | - Thi Thu An Nguyen
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | - Thi Hanh Nguyen Vu
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | - Thi Thanh Ngoc Nguyen
- Faculty of Food Technology, East Asia University of Technology, Hanoi, 100000, Vietnam
| | - Xuan Khoi Tran
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | - Nhat Huy Chu
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | | | - Hoang Ha Chu
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam
| | - Quyet-Tien Phi
- Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, 100000, Vietnam.
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Nontaleerak B, Eurtivong C, Weeraphan C, Buncherd H, Chokchaichamnankit D, Srisomsap C, Svasti J, Sukchawalit R, Mongkolsuk S. The redox-sensing mechanism of Agrobacterium tumefaciens NieR as a thiol-based oxidation sensor for hypochlorite stress. Free Radic Biol Med 2023; 208:211-220. [PMID: 37544488 DOI: 10.1016/j.freeradbiomed.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/20/2023] [Accepted: 08/01/2023] [Indexed: 08/08/2023]
Abstract
NieR is a TetR family transcriptional repressor previously shown to regulate the NaOCl-inducible efflux pump NieAB in Agrobacterium tumefaciens. NieR is an ortholog of Escherichia coli NemR that specifically senses hypochlorite through the redox switch of a reversible sulfenamide bond between C106 and K175. The amino acid sequence of NieR contains only one cysteine. NieR has C104 and R166, which correspond to C106 and K175 of NemR, respectively. The aim of this study was to investigate the redox-sensing mechanism of NieR under NaOCl stress. C104 and R166 were subjected to mutagenesis to determine their roles. Although the substitution of R166 by alanine slightly reduced its DNA-binding activity, NieR retained its repressor function. By contrast, the DNA-binding and repression activities of NieR were completely lost when C104 was replaced by alanine. C104 substitution with serine only partially impaired the repressor function. Mass spectrometry analysis revealed an intermolecular disulfide bond between the C104 residues of NieR monomers. This study demonstrates the engagement of C104 in the mechanism of NaOCl sensing. C104 oxidation induced the formation of a disulfide-linked dimer that was likely to alter conformation, thus abolishing the DNA-binding ability of NieR and derepressing the target genes.
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Affiliation(s)
- Benya Nontaleerak
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, 10210, Thailand
| | - Chatchakorn Eurtivong
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Si Ayutthaya Road, Ratchathewi, Bangkok 10400, Thailand
| | - Churat Weeraphan
- Laboratory of Biochemistry, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand
| | - Hansuk Buncherd
- Laboratory of Biochemistry, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand; Faculty of Medical Technology, Prince of Songkla University, Songkhla 90112, Thailand; Medical Science Research and Innovation Institute, Prince of Songkla University, Songkhla 90112, Thailand
| | | | - Chantragan Srisomsap
- Laboratory of Biochemistry, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand
| | - Jisnuson Svasti
- Laboratory of Biochemistry, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand
| | - Rojana Sukchawalit
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, 10210, Thailand; Program in Applied Biological Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Thailand.
| | - Skorn Mongkolsuk
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, 10210, Thailand; Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Thailand
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Crompton ME, Gaessler LF, Tawiah PO, Polzer L, Camfield SK, Jacobson GD, Naudszus MK, Johnson C, Meurer K, Bennis M, Roseberry B, Sultana S, Dahl JU. Expression of RcrB confers resistance to hypochlorous acid in uropathogenic Escherichia coli. J Bacteriol 2023; 205:e0006423. [PMID: 37791752 PMCID: PMC10601744 DOI: 10.1128/jb.00064-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/25/2023] [Indexed: 10/05/2023] Open
Abstract
To eradicate bacterial pathogens, neutrophils are recruited to the sites of infection, where they engulf and kill microbes through the production of reactive oxygen and chlorine species (ROS/RCS). The most prominent RCS is the antimicrobial oxidant hypochlorous acid (HOCl), which rapidly reacts with various amino acid side chains, including those containing sulfur and primary/tertiary amines, causing significant macromolecular damage. Pathogens like uropathogenic Escherichia coli (UPEC), the primary causative agent of urinary tract infections, have developed sophisticated defense systems to protect themselves from HOCl. We recently identified the RcrR regulon as a novel HOCl defense strategy in UPEC. Expression of the rcrARB operon is controlled by the HOCl-sensing transcriptional repressor RcrR, which is oxidatively inactivated by HOCl resulting in the expression of its target genes, including rcrB. The rcrB gene encodes a hypothetical membrane protein, deletion of which substantially increases UPEC's susceptibility to HOCl. However, the mechanism behind protection by RcrB is unclear. In this study, we investigated whether (i) its mode of action requires additional help, (ii) rcrARB expression is induced by physiologically relevant oxidants other than HOCl, and (iii) expression of this defense system is limited to specific media and/or cultivation conditions. We provide evidence that RcrB expression is sufficient to protect E. coli from HOCl. Furthermore, RcrB expression is induced by and protects from several RCS but not from ROS. RcrB plays a protective role for RCS-stressed planktonic cells under various growth and cultivation conditions but appears to be irrelevant for UPEC's biofilm formation. IMPORTANCE Bacterial infections pose an increasing threat to human health, exacerbating the demand for alternative treatments. Uropathogenic Escherichia coli (UPEC), the most common etiological agent of urinary tract infections (UTIs), are confronted by neutrophilic attacks in the bladder, and must therefore be equipped with powerful defense systems to fend off the toxic effects of reactive chlorine species. How UPEC deal with the negative consequences of the oxidative burst in the neutrophil phagosome remains unclear. Our study sheds light on the requirements for the expression and protective effects of RcrB, which we recently identified as UPEC's most potent defense system toward hypochlorous acid (HOCl) stress and phagocytosis. Thus, this novel HOCl stress defense system could potentially serve as an attractive drug target to increase the body's own capacity to fight UTIs.
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Affiliation(s)
- Mary E. Crompton
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Luca F. Gaessler
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Patrick O. Tawiah
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Lisa Polzer
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Sydney K. Camfield
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Grady D. Jacobson
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Maren K. Naudszus
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Colton Johnson
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Kennadi Meurer
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Mehdi Bennis
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Brendan Roseberry
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Sadia Sultana
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Jan-Ulrik Dahl
- Microbiology, School of Biological Sciences, Illinois State University, Normal, Illinois, USA
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5
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Yang Y, Zhou R, Yuan M, He H. Nano Ag/PPy Biocomposites Based on Graphene Oxide Modified Bacterial Cellulose from the Juice of Xinhui Citrus and Its Antibacterial Activity. MICROMACHINES 2023; 14:1809. [PMID: 37893246 PMCID: PMC10608959 DOI: 10.3390/mi14101809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/08/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023]
Abstract
Bacterial cellulose (BC) is a green, natural biopolymer with excellent biocompatibility and a film-forming ability. However, its lack of inherent antibacterial activity restricts its application in medical materials and food preservation. In this study, BC derived from the juice of discarded Xinhui citrus was obtained through fermentation and further modified in situ with graphene oxide (GO) to obtain BC(GO). Subsequently, BC(GO) was loaded with cell-compatible polypyrrole (PPy) and antibacterial agent silver nanoparticles (AgNPs) to prepare Ag-PPy/BC(GO) composite films. Composite films were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) to evaluate their chemical structure and morphology. The results demonstrate effective adsorption of PPy and AgNPs onto the surface of BC nanofibers modified with GO. Antibacterial experiments reveal synergistic antibacterial effects of PPy and AgNPs. The Ag-PPy/BC(GO) membranes exhibit strong antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with 48-h growth inhibition rates of 75-84% and 82-84%, respectively.
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Affiliation(s)
- Yihong Yang
- School of Materials Science and Food Engineering, Zhongshan Institute, University of Electronic Science and Technology of China, Zhongshan 528400, China; (R.Z.); (M.Y.); (H.H.)
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6
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Crompton ME, Gaessler LF, Tawiah PO, Pfirsching L, Camfield SK, Johnson C, Meurer K, Bennis M, Roseberry B, Sultana S, Dahl JU. Expression of RcrB confers resistance to hypochlorous acid in uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.01.543251. [PMID: 37398214 PMCID: PMC10312555 DOI: 10.1101/2023.06.01.543251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
To eradicate bacterial pathogens, neutrophils are recruited to the sites of infection, where they engulf and kill microbes through the production of reactive oxygen and chlorine species (ROS/RCS). The most prominent RCS is antimicrobial oxidant hypochlorous acid (HOCl), which rapidly reacts with various amino acids side chains, including those containing sulfur and primary/tertiary amines, causing significant macromolecular damage. Pathogens like uropathogenic Escherichia coli (UPEC), the primary causative agent of urinary tract infections (UTIs), have developed sophisticated defense systems to protect themselves from HOCl. We recently identified the RcrR regulon as a novel HOCl defense strategy in UPEC. The regulon is controlled by the HOCl-sensing transcriptional repressor RcrR, which is oxidatively inactivated by HOCl resulting in the expression of its target genes, including rcrB . rcrB encodes the putative membrane protein RcrB, deletion of which substantially increases UPEC's susceptibility to HOCl. However, many questions regarding RcrB's role remain open including whether (i) the protein's mode of action requires additional help, (ii) rcrARB expression is induced by physiologically relevant oxidants other than HOCl, and (iii) expression of this defense system is limited to specific media and/or cultivation conditions. Here, we provide evidence that RcrB expression is sufficient to E. coli 's protection from HOCl and induced by and protects from several RCS but not from ROS. RcrB plays a protective role for RCS-stressed planktonic cells under various growth and cultivation conditions but appears to be irrelevant for UPEC's biofilm formation. IMPORTANCE Bacterial infections pose an increasing threat to human health exacerbating the demand for alternative treatment options. UPEC, the most common etiological agent of urinary tract infections (UTIs), are confronted by neutrophilic attacks in the bladder, and must therefore be well equipped with powerful defense systems to fend off the toxic effects of RCS. How UPEC deal with the negative consequences of the oxidative burst in the neutrophil phagosome remains unclear. Our study sheds light on the requirements for the expression and protective effects of RcrB, which we recently identified as UPEC's most potent defense system towards HOCl-stress and phagocytosis. Thus, this novel HOCl-stress defense system could potentially serve as an attractive drug target to increase the body's own capacity to fight UTIs.
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Affiliation(s)
- Mary E. Crompton
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Luca F. Gaessler
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Patrick O. Tawiah
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Lisa Pfirsching
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Sydney K. Camfield
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Colton Johnson
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Kennadi Meurer
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Mehdi Bennis
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Brendan Roseberry
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Sadia Sultana
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
| | - Jan-Ulrik Dahl
- School of Biological Sciences, Illinois State University, Microbiology, Normal, IL, USA
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Biophysical and Biochemical Characterization of the Binding of the MarR-like Transcriptional Regulator Saro_0803 to the nov1 Promotor and Its Inhibition by Resveratrol. Biomolecules 2023; 13:biom13030541. [PMID: 36979476 PMCID: PMC10046596 DOI: 10.3390/biom13030541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
Saro_0803 is a transcriptional factor modulating the transcription of the stilbene-degrading enzyme gene nov1 in Novosphingobium aromaticivorans DSM 12444. Reportedly, Saro_0803 undergoes resveratrol-mediated dissociation from the nov1 promotor and distinguishes resveratrol from its precursors, p-coumaric acid and trans-cinnamic acid, enabling the transcriptional factor to serve as a biosensor component for regulating resveratrol biosynthesis. However, little is known about the molecular mechanisms underlying the Saro_0803 interactions with either the nov1 promotor gene or resveratrol, which undermines the potential for Saro_0803 to be further modified for improved biosynthetic performance and other applications. Here, we report the discovery of the 22 bp A/T-rich Saro_0803 binding site near the −10 box of the nov1 promotor (named nov1p22bp). As validated by molecular docking-guided mutagenesis and binding affinity assays, the Saro_0803 binding of its target DNA sequence relies on charge-predominating interactions between several typical positively charged residues and nucleic acid. Furthermore, we semi-quantified the influence of resveratrol presence on Saro_0803–nov1p22bp interaction and identified a bilateral hydrophobic pocket within Saro_0803 comprising four aromatic residues that are crucial to maintaining the resveratrol binding capability of the transcriptional factor. Our data are beneficial to understanding saro_0803′s structural and functional properties, and could provide theoretical clues for future adaptations of this transcriptional factor.
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Caporaletti F, Pietras Z, Morad V, Mårtensson LG, Gabel F, Wallner B, Martel A, Sunnerhagen M. Small-angle x-ray and neutron scattering of MexR and its complex with DNA supports a conformational selection binding model. Biophys J 2023; 122:408-418. [PMID: 36474441 PMCID: PMC9892617 DOI: 10.1016/j.bpj.2022.11.2949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 09/02/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
In this work, we used small-angle x-ray and neutron scattering to reveal the shape of the protein-DNA complex of the Pseudomonas aeruginosa transcriptional regulator MexR, a member of the multiple antibiotics resistance regulator (MarR) family, when bound to one of its native DNA binding sites. Several MarR-like proteins, including MexR, repress the expression of efflux pump proteins by binding to DNA on regulatory sites overlapping with promoter regions. When expressed, efflux proteins self-assemble to form multiprotein complexes and actively expel highly toxic compounds out of the host organism. The mutational pressure on efflux-regulating MarR family proteins is high since deficient DNA binding leads to constitutive expression of efflux pumps and thereby supports acquired multidrug resistance. Understanding the functional outcome of such mutations and their effects on DNA binding has been hampered by the scarcity of structural and dynamic characterization of both free and DNA-bound MarR proteins. Here, we show how combined neutron and x-ray small-angle scattering of both states in solution support a conformational selection model that enhances MexR asymmetry in binding to one of its promoter-overlapping DNA binding sites.
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Affiliation(s)
- Francesca Caporaletti
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden; Large Scale Structure, Institute Laue Langevin, Grenoble, France
| | - Zuzanna Pietras
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Vivian Morad
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Lars-Göran Mårtensson
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Frank Gabel
- University Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Björn Wallner
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Anne Martel
- Large Scale Structure, Institute Laue Langevin, Grenoble, France
| | - Maria Sunnerhagen
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden.
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Copley SD, Newton MS, Widney KA. How to Recruit a Promiscuous Enzyme to Serve a New Function. Biochemistry 2023; 62:300-308. [PMID: 35729117 PMCID: PMC9881647 DOI: 10.1021/acs.biochem.2c00249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Promiscuous enzymes can be recruited to serve new functions when a genetic or environmental change makes catalysis of a novel reaction important for fitness or even survival. Subsequently, gene duplication and divergence can lead to evolution of an efficient and specialized new enzyme. Every organism likely has thousands of promiscuous enzyme activities that provide a vast reservoir of catalytic potential. However, much of this potential may not be accessible. We compiled kinetic parameters for promiscuous reactions catalyzed by 108 enzymes. The median value of kcat/KM is a very modest 31 M-1 s-1. Based upon the fluxes through metabolic pathways in E. coli, we estimate that many, if not most, promiscuous activities are too inefficient to impact fitness. However, mutations can elevate the level of an insufficient promiscuous activity by increasing enzyme expression, improving kcat/KM, or altering concentrations of the promiscuous and native substrates and allosteric regulators. Particularly in large bacterial populations, stochastic mutations may provide a viable pathway for recruitment of even inefficient promiscuous activities.
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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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Beirne C, McCann E, McDowell A, Miliotis G. Genetic determinants of antimicrobial resistance in three multi-drug resistant strains of Cutibacterium acnes isolated from patients with acne: a predictive in silico study. Access Microbiol 2022; 4:acmi000404. [PMID: 36133174 PMCID: PMC9484663 DOI: 10.1099/acmi.0.000404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/06/2022] [Indexed: 01/09/2023] Open
Abstract
Objectives. Using available whole genome data, the objective of this in silico study was to identify genetic mechanisms that could explain the antimicrobial resistance profile of three multi-drug resistant (MDR) strains (CA17, CA51, CA39) of the skin bacterium
Cutibacterium acnes
previously recovered from patients with acne. In particular, we were interested in detecting novel genetic determinants associated with resistance to fluoroquinolone and macrolide antibiotics that could then be confirmed experimentally.
Methods. A range of open source bioinformatics tools were used to ‘mine’ genetic determinants of antimicrobial resistance and plasmid borne contigs, and to characterise the phylogenetic diversity of the MDR strains.
Results. As probable mechanisms of resistance to fluoroquinolones, we identified a previously described resistance associated allelic variant of the gyrA gene with a ‘deleterious' S101L mutation in type IA1 strains CA51 (ST1) and CA39 (ST1), as well as a novel E761R ‘deleterious’ mutation in the type II strain CA17 (ST153). A distinct genomic sequence of the efflux protein YfmO which is potentially associated with resistance to MLSB antibiotics was also present in CA17; homologues in CA51, CA39, and other strains of
Cutibacterium acnes
, were also found but differed in amino acid content. Strikingly, in CA17 we also identified a circular 2.7 kb non-conjugative plasmid (designated pCA17) that closely resembled a 4.8 kb plasmid (pYU39) from the MDR
Salmonella enterica
strain YU39.
Conclusions. This study has provided a detailed explanation of potential genetic determinants for MDR in the
Cutibacterium acnes
strains CA17, CA39 and CA51. Further laboratory investigations will be required to validate these in silico results, especially in relation to pCA17.
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Affiliation(s)
- Catriona Beirne
- Antimicrobial Resistance and Microbial Ecology Group, School of Medicine, National University of Ireland, Galway, Ireland
| | - Emily McCann
- Antimicrobial Resistance and Microbial Ecology Group, School of Medicine, National University of Ireland, Galway, Ireland
| | - Andrew McDowell
- Nutrition Innovation Centre for Food and Health, (NICHE), School of Biomedical Sciences, Ulster University, Coleraine, Ireland
| | - Georgios Miliotis
- Antimicrobial Resistance and Microbial Ecology Group, School of Medicine, National University of Ireland, Galway, Ireland
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Inducible knockdown of Mycobacterium smegmatis MSMEG_2975 (glyoxalase II) affected bacterial growth, antibiotic susceptibility, biofilm, and transcriptome. Arch Microbiol 2021; 204:97. [DOI: 10.1007/s00203-021-02652-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 10/03/2021] [Accepted: 10/07/2021] [Indexed: 10/19/2022]
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Lee IG, Lee BJ. How Bacterial Redox Sensors Transmit Redox Signals via Structural Changes. Antioxidants (Basel) 2021; 10:antiox10040502. [PMID: 33804871 PMCID: PMC8063818 DOI: 10.3390/antiox10040502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/04/2021] [Accepted: 03/17/2021] [Indexed: 01/17/2023] Open
Abstract
Bacteria, like humans, face diverse kinds of stress during life. Oxidative stress, which is produced by cellular metabolism and environmental factors, can significantly damage cellular macromolecules, ultimately negatively affecting the normal growth of the cell. Therefore, bacteria have evolved a number of protective strategies to defend themselves and respond to imposed stress by changing the expression pattern of genes whose products are required to convert harmful oxidants into harmless products. Structural biology combined with biochemical studies has revealed the mechanisms by which various bacterial redox sensor proteins recognize the cellular redox state and transform chemical information into structural signals to regulate downstream signaling pathways.
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Affiliation(s)
- In-Gyun Lee
- Chemical Kinomics Research Center, Korea Institute of Science and Technology (KIST), 5 Hwarangro 14-gil, Seongbuk-gu, Seoul 02792, Korea;
| | - Bong-Jin Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
- Correspondence:
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A Major Facilitator Superfamily (MFS) Efflux Pump, SCO4121, from Streptomyces coelicolor with Roles in Multidrug Resistance and Oxidative Stress Tolerance and Its Regulation by a MarR Regulator. Appl Environ Microbiol 2021; 87:AEM.02238-20. [PMID: 33483304 DOI: 10.1128/aem.02238-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
Overexpression of efflux pumps is one of the major determinants of resistance in bacteria. Streptomyces species harbor a large array of efflux pumps that are transcriptionally silenced under laboratory conditions. However, their dissemination results in multidrug resistance in different clinical pathogens. In this study, we have identified an efflux pump from Streptomyces coelicolor, SCO4121, belonging to the major facilitator superfamily (MFS) family of transporters and characterized its role in antibiotic resistance. SCO4121 provided resistance to multiple dissimilar drugs upon overexpression in both native and heterologous hosts. Further, deletion of SCO4121 resulted in increased sensitivity toward ciprofloxacin and chloramphenicol, suggesting the pump to be a major transporter of these substrates. Apart from providing multidrug resistance, SCO4121 imparted increased tolerance against the strong oxidant HOCl. In wild-type Streptomyces coelicolor cells, these drugs were found to transcriptionally regulate the pump in a concentration-dependent manner. Additionally, we identified SCO4122, a MarR regulator that positively regulates SCO4121 in response to various drugs and the oxidant HOCl. Thus, through these studies we present the multiple roles of SCO4121 in S. coelicolor and highlight the intricate mechanisms via which it is regulated in response to antibiotics and oxidative stress.IMPORTANCE One of the key mechanisms of drug resistance in bacteria is overexpression of efflux pumps. Streptomyces species are a reservoir of a large number of efflux pumps, potentially to provide resistance to both endogenous and nonendogenous antibiotics. While many of these pumps are not expressed under standard laboratory conditions, they result in resistance to multiple drugs when spread to other bacterial pathogens through horizontal gene transfer. In this study, we have identified a widely conserved efflux pump SCO4121 from Streptomyces coelicolor with roles in both multidrug resistance and oxidative stress tolerance. We also report the presence of an adjacent MarR regulator, SCO4122, which positively regulates SCO4121 in the presence of diverse substrates in a redox-responsive manner. This study highlights that soil bacteria such as Streptomyces can reveal novel mechanisms of antibiotic resistance that may potentially emerge in clinically important bacteria.
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Varatnitskaya M, Degrossoli A, Leichert LI. Redox regulation in host-pathogen interactions: thiol switches and beyond. Biol Chem 2020; 402:299-316. [PMID: 33021957 DOI: 10.1515/hsz-2020-0264] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/29/2020] [Indexed: 12/23/2022]
Abstract
Our organism is exposed to pathogens on a daily basis. Owing to this age-old interaction, both pathogen and host evolved strategies to cope with these encounters. Here, we focus on the consequences of the direct encounter of cells of the innate immune system with bacteria. First, we will discuss the bacterial strategies to counteract powerful reactive species. Our emphasis lies on the effects of hypochlorous acid (HOCl), arguably the most powerful oxidant produced inside the phagolysosome of professional phagocytes. We will highlight individual examples of proteins in gram-negative bacteria activated by HOCl via thiol-disulfide switches, methionine sulfoxidation, and N-chlorination of basic amino acid side chains. Second, we will discuss the effects of HOCl on proteins of the host. Recent studies have shown that both host and bacteria address failing protein homeostasis by activation of chaperone-like holdases through N-chlorination. After discussing the role of individual proteins in the HOCl-defense, we will turn our attention to the examination of effects on host and pathogen on a systemic level. Recent studies using genetically encoded redox probes and redox proteomics highlight differences in redox homeostasis in host and pathogen and give first hints at potential cellular HOCl signaling beyond thiol-disulfide switch mechanisms.
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Affiliation(s)
- Marharyta Varatnitskaya
- Institute for Biochemistry and Pathobiochemistry - Microbial Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Adriana Degrossoli
- Faculty of Health Science - Health Science Department, Federal University of Lavras, Lavras, Brazil
| | - Lars I Leichert
- Institute for Biochemistry and Pathobiochemistry - Microbial Biochemistry, Ruhr University Bochum, Bochum, Germany
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Mourenza Á, Gil JA, Mateos LM, Letek M. Oxidative Stress-Generating Antimicrobials, a Novel Strategy to Overcome Antibacterial Resistance. Antioxidants (Basel) 2020; 9:antiox9050361. [PMID: 32357394 PMCID: PMC7278815 DOI: 10.3390/antiox9050361] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 02/07/2023] Open
Abstract
Antimicrobial resistance is becoming one of the most important human health issues. Accordingly, the research focused on finding new antibiotherapeutic strategies is again becoming a priority for governments and major funding bodies. The development of treatments based on the generation of oxidative stress with the aim to disrupt the redox defenses of bacterial pathogens is an important strategy that has gained interest in recent years. This approach is allowing the identification of antimicrobials with repurposing potential that could be part of combinatorial chemotherapies designed to treat infections caused by recalcitrant bacterial pathogens. In addition, there have been important advances in the identification of novel plant and bacterial secondary metabolites that may generate oxidative stress as part of their antibacterial mechanism of action. Here, we revised the current status of this emerging field, focusing in particular on novel oxidative stress-generating compounds with the potential to treat infections caused by intracellular bacterial pathogens.
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