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Rojas VK, Winter MG, Jimenez AG, Tanner NW, Crockett SL, Spiga L, Hendrixson DR, Winter SE. Infection-associated gene regulation of L-tartrate metabolism in Salmonella enterica serovar Typhimurium. mBio 2024; 15:e0035024. [PMID: 38682906 DOI: 10.1128/mbio.00350-24] [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: 02/02/2024] [Accepted: 03/28/2024] [Indexed: 05/01/2024] Open
Abstract
Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for the sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, the regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, i.e., substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes the utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection. IMPORTANCE Bacterial pathogens must adapt their gene expression profiles to cope with diverse environments encountered during infection. This coordinated process is carried out by the integration of cues that the pathogen senses to fine-tune gene expression in a spatiotemporal manner. Many studies have elucidated the regulatory mechanisms of how Salmonella sense metabolites in the gut to activate or repress its virulence program; however, our understanding of how Salmonella coordinates its gene expression to maximize the utilization of carbon and energy sources found in transitional nutrient niches is not well understood. In this study, we discovered how Salmonella integrates two infection-relevant cues, substrate availability and exogenous electron acceptors, to control L-tartrate metabolism. From our experiments, we propose a model for how L-tartrate metabolism is regulated in response to different metabolic cues in addition to characterizing two previously unknown transcriptional regulators. This study expands our understanding of how microbes combine metabolic cues to enhance fitness during infection.
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Affiliation(s)
- Vivian K Rojas
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Maria G Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Angel G Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Natasha W Tanner
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
| | - Stacey L Crockett
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Luisella Spiga
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sebastian E Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, California, USA
- Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, California, USA
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2
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Ma XQ, Wang B, Wei W, Tan FC, Su H, Zhang JZ, Zhao CY, Zheng HJ, Feng YQ, Shen W, Yang JB, Li FL. Alginate oligosaccharide assimilation by gut microorganisms and the potential role in gut inflammation alleviation. Appl Environ Microbiol 2024; 90:e0004624. [PMID: 38563787 PMCID: PMC11107165 DOI: 10.1128/aem.00046-24] [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: 01/08/2024] [Accepted: 03/10/2024] [Indexed: 04/04/2024] Open
Abstract
Dietary fiber metabolism by gut microorganisms plays important roles in host physiology and health. Alginate, the major dietary fiber of daily diet seaweeds, is drawing more attention because of multiple biological activities. To advance the understanding of alginate assimilation mechanism in the gut, we show the presence of unsaturated alginate oligosaccharides (uAOS)-specific alginate utilization loci (AUL) in human gut microbiome. As a representative example, a working model of the AUL from the gut microorganism Bacteroides clarus was reconstructed from biochemistry and transcriptome data. The fermentation of resulting monosaccharides through Entner-Doudoroff pathway tunes the metabolism of short-chain fatty acids and amino acids. Furthermore, we show that uAOS feeding protects the mice against dextran sulfate sodium-induced acute colitis probably by remodeling gut microbiota and metabolome. IMPORTANCE Alginate has been included in traditional Chinese medicine and daily diet for centuries. Recently discovered biological activities suggested that alginate-derived alginate oligosaccharides (AOS) might be an active ingredient in traditional Chinese medicine, but how these AOS are metabolized in the gut and how it affects health need more information. The study on the working mechanism of alginate utilization loci (AUL) by the gut microorganism uncovers the role of unsaturated alginate oligosaccharides (uAOS) assimilation in tuning short-chain fatty acids and amino acids metabolism and demonstrates that uAOS metabolism by gut microorganisms results in a variation of cell metabolites, which potentially contributes to the physiology and health of gut.
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Affiliation(s)
- Xiao-Qing Ma
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Bing Wang
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Wei Wei
- Innovation Center of Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Fang-Cheng Tan
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Hang Su
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Jun-Zhe Zhang
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Chen-Yang Zhao
- Innovation Center of Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Hua-Jun Zheng
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China
| | - Yan-Qin Feng
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Wei Shen
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Jin-Bo Yang
- Innovation Center of Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Fu-Li Li
- Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Shandong Energy Institute, Qingdao, China
- Qingdao New Energy Shandong Laboratory, Qingdao, China
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3
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Rojas VK, Winter MG, Jimenez AG, Tanner NW, Crockett SL, Spiga L, Hendrixson DR, Winter SE. Gene regulation of infection-associated L-tartrate metabolism in Salmonella enterica serovar Typhimurium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.578992. [PMID: 38370731 PMCID: PMC10871181 DOI: 10.1101/2024.02.05.578992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection.
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Affiliation(s)
- Vivian K. Rojas
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Maria G. Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Angel G. Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Current address: Infectious Diseases, Genentech, South San Francisco, California, USA
| | - Natasha W. Tanner
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
| | - Stacey L. Crockett
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Luisella Spiga
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Current address: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David R. Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sebastian E. Winter
- Department of Internal Medicine, Division of Infectious Diseases, UC Davis School of Medicine, Davis, CA, USA
- Department of Medical Microbiology and Immunology, UC Davis School of Medicine, Davis, CA, USA
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Smiley MK, Sekaran DC, Forouhar F, Wolin E, Jovanovic M, Price-Whelan A, Dietrich LEP. MpaR-driven expression of an orphan terminal oxidase subunit supports Pseudomonas aeruginosa biofilm respiration and development during cyanogenesis. mBio 2024; 15:e0292623. [PMID: 38112469 PMCID: PMC10790758 DOI: 10.1128/mbio.02926-23] [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: 11/03/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Cyanide is an inhibitor of heme-copper oxidases, which are required for aerobic respiration in all eukaryotes and many prokaryotes. This fast-acting poison can arise from diverse sources, but mechanisms by which bacteria sense it are poorly understood. We investigated the regulatory response to cyanide in the pathogenic bacterium Pseudomonas aeruginosa, which produces cyanide as a virulence factor. Although P. aeruginosa has the capacity to produce a cyanide-resistant oxidase, it relies primarily on heme-copper oxidases and even makes additional heme-copper oxidase proteins specifically under cyanide-producing conditions. We found that the protein MpaR controls expression of cyanide-inducible genes in P. aeruginosa and elucidated the molecular details of this regulation. MpaR contains a DNA-binding domain and a domain predicted to bind pyridoxal phosphate (vitamin B6), a compound that is known to react spontaneously with cyanide. These observations provide insight into the understudied phenomenon of cyanide-dependent regulation of gene expression in bacteria.
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Affiliation(s)
- Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Doran C. Sekaran
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Farhad Forouhar
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA
| | - Erica Wolin
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Lars E. P. Dietrich
- Department of Biological Sciences, Columbia University, New York, New York, USA
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5
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Lassak J, Aveta EF, Vougioukas P, Hellwig M. Non-canonical food sources: bacterial metabolism of Maillard reaction products and its regulation. Curr Opin Microbiol 2023; 76:102393. [PMID: 37844449 DOI: 10.1016/j.mib.2023.102393] [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: 07/20/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 10/18/2023]
Abstract
Proteins are an important part of our regular diet. During food processing, their amino acid composition can be chemically altered by the reaction of free amino groups with sugars - a process termed glycation. The resulting Maillard reaction products (MRPs) have low bioavailability and thus predominantly end up in the colon where they encounter our gut microbiota. In the following review, we summarize bacterial strategies to efficiently metabolize these non-canonical amino acids. A particular focus will be on the complex regulatory mechanisms that allow a tightly controlled expression of metabolic genes to successfully occupy the ecological niches that result from the chemical diversity of MRPs.
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Affiliation(s)
- Jürgen Lassak
- Fakultät für Biologie, Lehrstuhl Mikrobiologie/AG Mikrobielle Biochemie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany.
| | - Erica F Aveta
- Fakultät für Biologie, Lehrstuhl Mikrobiologie/AG Mikrobielle Biochemie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
| | - Patroklos Vougioukas
- Fakultät Chemie und Lebensmittelchemie, Professur für Spezielle Lebensmittelchemie, Technische Universität Dresden, Bergstraße 66, D-01062 Dresden, Germany
| | - Michael Hellwig
- Fakultät Chemie und Lebensmittelchemie, Professur für Spezielle Lebensmittelchemie, Technische Universität Dresden, Bergstraße 66, D-01062 Dresden, Germany.
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6
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Maity D, Singh D, Bandhu A. Mce1R of Mycobacterium tuberculosis prefers long-chain fatty acids as specific ligands: a computational study. Mol Divers 2023; 27:2523-2543. [PMID: 36385433 DOI: 10.1007/s11030-022-10566-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 11/04/2022] [Indexed: 11/17/2022]
Abstract
The mce1 operon of Mycobacterium tuberculosis, which codes the Mce1 transporter, facilitates the transport of fatty acids. Fatty acids are one of the major sources for carbon and energy for the pathogen during its intracellular survival and pathogenicity. The mce1 operon is transcriptionally regulated by Mce1R, a VanR-type regulator, which could bind specific ligands and control the expression of the mce1 operon accordingly. This work reports computational identification of Mce1R-specific ligands. Initially by employing cavity similarity search algorithm by the ProBis server, the cavities of the proteins similar to that of Mce1R and the bound ligands were identified from which fatty acids were selected as the potential ligands. From the earlier-generated monomeric structure, the dimeric structure of Mce1R was then modeled by the GalaxyHomomer server and validated computationally to use in molecular docking and molecular dynamics simulation analysis. The fatty acid ligands were found to dock within the cavity of Mce1R and the docked complexes were subjected to molecular dynamics simulation to explore their stabilities and other dynamic properties. The data suggest that Mce1R preferably binds to long-chain fatty acids and undergoes distinct structural changes upon binding.
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Affiliation(s)
- Dipanwita Maity
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, 506004, India
| | - Dheeraj Singh
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, 506004, India
| | - Amitava Bandhu
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, 506004, India.
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7
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Zhang SP, Ye YP, Hou J, Ye ZR, Wang ZS, Yu XQ, Guo DD, Wang Y, He YX. Antitoxin MqsA decreases antibiotic susceptibility through the global regulator AgtR in Pseudomonas fluorescens. Antimicrob Agents Chemother 2023; 67:e0081223. [PMID: 37877694 PMCID: PMC10649091 DOI: 10.1128/aac.00812-23] [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: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/26/2023] Open
Abstract
Type II toxin-antitoxin systems are highly prevalent in bacterial genomes and play crucial roles in the general stress response. Previously, we demonstrated that the type II antitoxin PfMqsA regulates biofilm formation through the global regulator AgtR in Pseudomonas fluorescens. Here, we found that both the C-terminal DNA-binding domain of PfMqsA and AgtR are involved in bacterial antibiotic susceptibility. Electrophoretic mobility shift assay (EMSA) analyses revealed that AgtR, rather than PfMqsA, binds to the intergenic region of emhABC-emhR, in which emhABC encodes an resistance-nodulation-cell division efflux pump and emhR encodes a repressor. Through quantitative real-time reverse-transcription PCR and EMSA analysis, we showed that AgtR directly activates the expression of the emhR by binding to the DNA motif [5´-CTAAGAAATATACTTAC-3´], leading to repression of the emhABC. Furthermore, we demonstrated that PfMqsA modulates the expression of EmhABC and EmhR. These findings enhance our understanding of the mechanism by which antitoxin PfMqsA contributes to antibiotic susceptibility.
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Affiliation(s)
- Si-Ping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yi-Ping Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Jun Hou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zi-Rui Ye
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Zhi-Song Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Xiao-Quan Yu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Ding-Ding Guo
- School of Pharmacy, Lanzhou University, Lanzhou, Gansu, China
| | - Yong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
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Zhao J, Sun X, Mao Z, Zheng Y, Geng Z, Zhang Y, Ma H, Wang Z. Independent component analysis of Corynebacterium glutamicum transcriptomes reveals its transcriptional regulatory network. Microbiol Res 2023; 276:127485. [PMID: 37683565 DOI: 10.1016/j.micres.2023.127485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
Gene expression in bacteria is regulated by multiple transcription factors. Clarifying the regulation mechanism of gene expression is necessary to understand bacterial physiological activities. To further understand the structure of the transcriptional regulatory network of Corynebacterium glutamicum, we applied independent component analysis, an unsupervised machine learning algorithm, to the high-quality C. glutamicum gene expression profile which includes 263 samples from 29 independent projects. We obtained 87 robust independent regulatory modules (iModulons). These iModulons explain 76.7% of the variance in the expression profile and constitute the quantitative transcriptional regulatory network of C. glutamicum. By analyzing the constituent genes in iModulons, we identified potential targets for 20 transcription factors. We also captured the changes in iModulon activities under different growth rates and dissolved oxygen concentrations, demonstrating the ability of iModulons to comprehensively interpret transcriptional responses to environmental changes. In summary, this study provides a genome-scale quantitative transcriptional regulatory network for C. glutamicum and informs future research on complex changes in the transcriptome.
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Affiliation(s)
- Jianxiao Zhao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Xi Sun
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Zhitao Mao
- Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Yangyang Zheng
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Zhouxiao Geng
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yuhan Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Hongwu Ma
- Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China.
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
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9
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Bhowmick A, Bhakta K, Roy M, Gupta S, Das J, Samanta S, Patranabis S, Ghosh A. Heat shock response in Sulfolobus acidocaldarius and first implications for cross-stress adaptation. Res Microbiol 2023; 174:104106. [PMID: 37516156 DOI: 10.1016/j.resmic.2023.104106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/15/2023] [Accepted: 07/21/2023] [Indexed: 07/31/2023]
Abstract
Sulfolobus acidocaldarius, a thermoacidophilic crenarchaeon, frequently encounters temperature fluctuations, oxidative stress, and nutrient limitations in its environment. Here, we employed a high-throughput transcriptomic analysis to examine how the gene expression of S. acidocaldarius changes when exposed to high temperatures (92 °C). The data obtained was subsequently validated using quantitative reverse transcription-PCR (qRT-PCR) analysis. Our particular focus was on genes that are involved in the heat shock response, type-II Toxin-Antitoxin systems, and putative transcription factors. To investigate how S. acidocaldarius adapts to multiple stressors, we assessed the expression of these selected genes under oxidative and nutrient stresses using qRT-PCR analysis. The results demonstrated that the gene thβ encoding the β subunit of the thermosome, as well as hsp14 and hsp20, play crucial roles in the majority of stress conditions. Furthermore, we observed overexpression of at least eight different TA pairs belonging to the type II TA systems under all stress conditions. Additionally, four common transcription factors: FadR, TFEβ, CRISPR loci binding protein, and HTH family protein were consistently overexpressed across all stress conditions, indicating their significant role in managing stress. Overall, this work provides the first insight into molecular players involved in the cross-stress adaptation of S. acidocaldarius.
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Affiliation(s)
- Arghya Bhowmick
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | - Koustav Bhakta
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | - Mousam Roy
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | - Sayandeep Gupta
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | - Jagriti Das
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | - Shirsha Samanta
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India
| | | | - Abhrajyoti Ghosh
- Department of Biological Sciences, Bose Institute, EN Block, Sector-V, Kolkata-700091, India.
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10
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Patil RS, Sharma S, Bhaskarwar AV, Nambiar S, Bhat NA, Koppolu MK, Bhukya H. TetR and OmpR family regulators in natural product biosynthesis and resistance. Proteins 2023. [PMID: 37874037 DOI: 10.1002/prot.26621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications.
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Affiliation(s)
- Rachit S Patil
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Siddhant Sharma
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Aditya V Bhaskarwar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Souparnika Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Niharika A Bhat
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Mani Kanta Koppolu
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Hussain Bhukya
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
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11
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Marshall A, McGrath JW, Mitchell M, Fanning S, McMullan G. One size does not fit all - Trehalose metabolism by Clostridioides difficile is variable across the five phylogenetic lineages. Microb Genom 2023; 9:001110. [PMID: 37768179 PMCID: PMC10569727 DOI: 10.1099/mgen.0.001110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
Clostridioides difficile, the leading cause of antibiotic-associated diarrhoea worldwide, is a genetically diverse species which can metabolise a number of nutrient sources upon colonising a dysbiotic gut environment. Trehalose, a disaccharide sugar consisting of two glucose molecules bonded by an α 1,1-glycosidic bond, has been hypothesised to be involved in the emergence of C. difficile hypervirulence due to its increased utilisation by the RT027 and RT078 strains. Here, growth in trehalose as the sole carbon source was shown to be non-uniform across representative C. difficile strains, even though the genes for its metabolism were induced. Growth in trehalose reduced the expression of genes associated with toxin production and sporulation in the C. difficile R20291 (RT027) and M120 (RT078) strains in vitro, suggesting an inhibitory effect on virulence factors. Interestingly, the R20291 TreR transcriptional regulatory protein appeared to possess an activator function as its DNA-binding ability was increased in the presence of its effector, trehalose-6-phosphate. Using RNA-sequencing analysis, we report the identification of a putative trehalose metabolism pathway which is induced during growth in trehalose: this has not been previously described within the C. difficile species. These data demonstrate the metabolic diversity exhibited by C. difficile which warrants further investigation to elucidate the molecular basis of trehalose metabolism within this important gut pathogen.
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Affiliation(s)
- Andrew Marshall
- School of Biological Sciences, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
| | - John W. McGrath
- School of Biological Sciences, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
| | - Molly Mitchell
- University College Dublin-Centre for Food Safety University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- University College Dublin-Centre for Food Safety University College Dublin, Dublin, Ireland
| | - Geoff McMullan
- School of Biological Sciences, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
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12
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Freda I, Exertier C, Barile A, Chaves-Sanjuan A, Vega M, Isupov M, Harmer N, Gugole E, Swuec P, Bolognesi M, Scipioni A, Savino C, Di Salvo M, Contestabile R, Vallone B, Tramonti A, Montemiglio L. Structural insights into the DNA recognition mechanism by the bacterial transcription factor PdxR. Nucleic Acids Res 2023; 51:8237-8254. [PMID: 37378428 PMCID: PMC10450172 DOI: 10.1093/nar/gkad552] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 06/08/2023] [Accepted: 06/22/2023] [Indexed: 06/29/2023] Open
Abstract
Specificity in protein-DNA recognition arises from the synergy of several factors that stem from the structural and chemical signatures encoded within the targeted DNA molecule. Here, we deciphered the nature of the interactions driving DNA recognition and binding by the bacterial transcription factor PdxR, a member of the MocR family responsible for the regulation of pyridoxal 5'-phosphate (PLP) biosynthesis. Single particle cryo-EM performed on the PLP-PdxR bound to its target DNA enabled the isolation of three conformers of the complex, which may be considered as snapshots of the binding process. Moreover, the resolution of an apo-PdxR crystallographic structure provided a detailed description of the transition of the effector domain to the holo-PdxR form triggered by the binding of the PLP effector molecule. Binding analyses of mutated DNA sequences using both wild type and PdxR variants revealed a central role of electrostatic interactions and of the intrinsic asymmetric bending of the DNA in allosterically guiding the holo-PdxR-DNA recognition process, from the first encounter through the fully bound state. Our results detail the structure and dynamics of the PdxR-DNA complex, clarifying the mechanism governing the DNA-binding mode of the holo-PdxR and the regulation features of the MocR family of transcription factors.
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Affiliation(s)
- Ida Freda
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza, University of Rome, Rome 00185, Italy
| | - Cécile Exertier
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
| | - Anna Barile
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
| | - Antonio Chaves-Sanjuan
- Department of Biosciences, Pediatric Clinical Research Center Romeo ed Enrica Invernizzi and NOLIMITS, University of Milano, Milano 20133, Italy
| | - Mirella Vivoli Vega
- School of Biochemistry, University of Bristol, University Walk, BS8 1TD Bristol, UK
| | - Michail N Isupov
- Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Nicholas J Harmer
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Elena Gugole
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
| | - Paolo Swuec
- Cryo-Electron Microscopy Core Facility, Human Technopole, Milano 20157, Italy
| | - Martino Bolognesi
- Department of Biosciences, Pediatric Clinical Research Center Romeo ed Enrica Invernizzi and NOLIMITS, University of Milano, Milano 20133, Italy
| | - Anita Scipioni
- Department of Chemistry, Sapienza, University of Rome, Rome 00185, Italy
| | - Carmelinda Savino
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
| | - Martino Luigi Di Salvo
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza, University of Rome, Rome 00185, Italy
| | - Roberto Contestabile
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza, University of Rome, Rome 00185, Italy
- Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza, University of Rome, Rome 00185, Italy
| | - Beatrice Vallone
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza, University of Rome, Rome 00185, Italy
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
| | - Angela Tramonti
- Institute of Molecular Biology and Pathology, National Research Council, Rome 00185, Italy
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13
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Zhu Q, Bai X, Li Q, Zhang M, Hu G, Pan K, Liu H, Ke Z, Hong Q, Qiu J. PcaR, a GntR/FadR Family Transcriptional Repressor Controls the Transcription of Phenazine-1-Carboxylic Acid 1,2-Dioxygenase Gene Cluster in Sphingomonas histidinilytica DS-9. Appl Environ Microbiol 2023; 89:e0212122. [PMID: 37191535 PMCID: PMC10304782 DOI: 10.1128/aem.02121-22] [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: 12/16/2022] [Accepted: 04/29/2023] [Indexed: 05/17/2023] Open
Abstract
In our previous study, the phenazine-1-carboxylic acid (PCA) 1,2-dioxygenase gene cluster (pcaA1A2A3A4 cluster) in Sphingomonas histidinilytica DS-9 was identified to be responsible for the conversion of PCA to 1,2-dihydroxyphenazine (Ren Y, Zhang M, Gao S, Zhu Q, et al. 2022. Appl Environ Microbiol 88:e00543-22). However, the regulatory mechanism of the pcaA1A2A3A4 cluster has not been elucidated yet. In this study, the pcaA1A2A3A4 cluster was found to be transcribed as two divergent operons: pcaA3-ORF5205 (named A3-5205 operon) and pcaA1A2-ORF5208-pcaA4-ORF5210 (named A1-5210 operon). The promoter regions of the two operons were overlapped. PcaR acts as a transcriptional repressor of the pcaA1A2A3A4 cluster, and it belongs to GntR/FadR family transcriptional regulator. Gene disruption of pcaR can shorten the lag phase of PCA degradation. The results of electrophoretic mobility shift assay and DNase I footprinting showed that PcaR binds to a 25-bp motif in the ORF5205-pcaA1 intergenic promoter region to regulate the expression of two operons. The 25-bp motif covers the -10 region of the promoter of A3-5205 operon and the -35 region and -10 region of the promoter of A1-5210 operon. The TNGT/ANCNA box within the motif was essential for PcaR binding to the two promoters. PCA acted as an effector of PcaR, preventing it from binding to the promoter region and repressing the transcription of the pcaA1A2A3A4 cluster. In addition, PcaR represses its own transcription, and this repression can be relieved by PCA. This study reveals the regulatory mechanism of PCA degradation in strain DS-9, and the identification of PcaR increases the variety of regulatory model of the GntR/FadR-type regulator. IMPORTANCE Sphingomonas histidinilytica DS-9 is a phenazine-1-carboxylic acid (PCA)-degrading strain. The 1,2-dioxygenase gene cluster (pcaA1A2A3A4 cluster, encoding dioxygenase PcaA1A2, reductase PcaA3, and ferredoxin PcaA4) is responsible for the initial degradation step of PCA and widely distributed in Sphingomonads, but its regulatory mechanism has not been investigated yet. In this study, a GntR/FadR-type transcriptional regulator PcaR repressing the transcription of pcaA1A2A3A4 cluster and pcaR gene was identified and characterized. The binding site of PcaR in ORF5205-pcaA1 intergenic promoter region contains a TNGT/ANCNA box, which is important for the binding. These findings enhance our understanding of the molecular mechanism of PCA degradation.
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Affiliation(s)
- Qian Zhu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Xuekun Bai
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Qian Li
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Mingliang Zhang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Gang Hu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Kaihua Pan
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Hongfei Liu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Zhijian Ke
- School of Biological and Chemical Engineering, Ningbo Tech University, Ningbo, Zhejiang, People’s Republic of China
| | - Qing Hong
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
| | - Jiguo Qiu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People’s Republic of China
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14
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Smiley MK, Sekaran DC, Price-Whelan A, Dietrich LE. Cyanide-dependent control of terminal oxidase hybridization by Pseudomonas aeruginosa MpaR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543164. [PMID: 37398129 PMCID: PMC10312525 DOI: 10.1101/2023.05.31.543164] [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
Pseudomonas aeruginosa is a common, biofilm-forming pathogen that exhibits complex pathways of redox metabolism. It produces four different types of terminal oxidases for aerobic respiration, and for one of these-the cbb3-type terminal oxidases-it has the capacity to produce at least 16 isoforms encoded by partially redundant operons. It also produces small-molecule virulence factors that interact with the respiratory chain, including the poison cyanide. Previous studies had indicated a role for cyanide in activating expression of an "orphan" terminal oxidase subunit gene called ccoN4 and that the product contributes to P. aeruginosa cyanide resistance, fitness in biofilms, and virulence-but the mechanisms underlying this process had not been elucidated. Here, we show that the regulatory protein MpaR, which is predicted to be a pyridoxal phosphate-binding transcription factor and is encoded just upstream of ccoN4, controls ccoN4 expression in response to endogenous cyanide. Paradoxically, we find that cyanide production is required to support CcoN4's contribution to respiration in biofilms. We identify a palindromic motif required for cyanide- and MpaR-dependent expression of ccoN4 and co-expressed, adjacent loci. We also characterize the regulatory logic of this region of the chromosome. Finally, we identify residues in the putative cofactor-binding pocket of MpaR that are required for ccoN4 expression. Together, our findings illustrate a novel scenario in which the respiratory toxin cyanide acts as a signal to control gene expression in a bacterium that produces the compound endogenously.
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Affiliation(s)
- Marina K. Smiley
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Doran C. Sekaran
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10025
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15
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Pathiraja D, Park B, Kim B, Stougaard P, Choi IG. Constructing Marine Bacterial Metabolic Chassis for Potential Biorefinery of Red Algal Biomass and Agaropectin Wastes. ACS Synth Biol 2023; 12:1782-1793. [PMID: 37265394 DOI: 10.1021/acssynbio.3c00063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Marine red algal biomass is a promising feedstock for sustainable production of value-added chemicals. However, the major constituents of red algal biomass, such as agar and carrageenan, are not easily assimilated by most industrial metabolic chassis developed to date. Synthetic biology offers a solution by utilizing nonmodel organisms as metabolic chassis for consolidated biological processes. In this study, the marine heterotrophic bacterium Pseudoalteromonas atlantica T6c was harnessed as a metabolic chassis to produce value-added chemicals from the affordable red algal galactans or agaropectin, a byproduct of industrial agarose production. To construct a heterologous gene expression device in P. atlantica T6c, promoters related to agar metabolism were screened from the differentially expressed genes using RNA-Seq analysis. The expression device was built and tested with selected promoters fused to a reporter gene and tuned by incorporation of a cognate repressor predicted from the agar-specific polysaccharide utilization locus. The feasibility of the marine bacterial metabolic chassis was examined by introducing the biosynthetic gene clusters of β-carotene and violacein. Our results demonstrate that the metabolic chassis platform enables direct conversion of low-cost red algal galactans or industrial waste agaropectin into valuable bioactive pigments without any pretreatment of biomass. The developed marine bacterial chassis could potentially be used in a biorefinery framework to produce value-added chemicals from marine algal galactans.
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Affiliation(s)
- Duleepa Pathiraja
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Byeonghyeok Park
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Bogun Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Peter Stougaard
- Department of Environmental Sciences, Aarhus University, DK-4000, Rockslide, Denmark
| | - In-Geol Choi
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
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16
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Meng Q, Xu Q, Xu Y, Ren H, Ge X, Yu J, Cao X, Yin J, Yu Z. A FadR-Type Regulator Activates the Biodegradation of Polycyclic Aromatic Hydrocarbons by Mediating Quorum Sensing in Croceicoccus naphthovorans Strain PQ-2. Appl Environ Microbiol 2023; 89:e0043323. [PMID: 37098893 PMCID: PMC10231186 DOI: 10.1128/aem.00433-23] [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: 03/14/2023] [Accepted: 04/04/2023] [Indexed: 04/27/2023] Open
Abstract
Bacteria employ multiple transcriptional regulators to orchestrate cellular responses to adapt to constantly varying environments. The bacterial biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been extensively described, and yet, the PAH-related transcriptional regulators remain elusive. In this report, we identified an FadR-type transcriptional regulator that controls phenanthrene biodegradation in Croceicoccus naphthovorans strain PQ-2. The expression of fadR in C. naphthovorans PQ-2 was induced by phenanthrene, and its deletion significantly impaired both the biodegradation of phenanthrene and the synthesis of acyl-homoserine lactones (AHLs). In the fadR deletion strain, the biodegradation of phenanthrene could be recovered by supplying either AHLs or fatty acids. Notably, FadR simultaneously activated the fatty acid biosynthesis pathway and repressed the fatty acid degradation pathway. As intracellular AHLs are synthesized with fatty acids as substrates, boosting the fatty acid supply could enhance AHL synthesis. Collectively, these findings demonstrate that FadR in C. naphthovorans PQ-2 positively regulates PAH biodegradation by controlling the formation of AHLs, which is mediated by the metabolism of fatty acids. IMPORTANCE Master transcriptional regulation of carbon catabolites is extremely important for the survival of bacteria that face changes in carbon sources. Polycyclic aromatic hydrocarbons (PAHs) can be utilized as carbon sources by some bacteria. FadR is a well-known transcriptional regulator involved in fatty acid metabolism; however, the connection between FadR regulation and PAH utilization in bacteria remains unknown. This study revealed that a FadR-type regulator in Croceicoccus naphthovorans PQ-2 stimulated PAH biodegradation by controlling the biosynthesis of the acyl-homoserine lactone quorum-sensing signals that belong to fatty acid-derived compounds. These results provide a unique perspective for understanding bacterial adaptation to PAH-containing environments.
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Affiliation(s)
- Qiu Meng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Qimiao Xu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Yinming Xu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Huiping Ren
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Xuzhe Ge
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Jianming Yu
- College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Xueqiang Cao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
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Niu K, Meng Y, Liu M, Ma Z, Lin H, Zhou H, Fan H. Phosphorylation of GntR reduces Streptococcus suis oxidative stress resistance and virulence by inhibiting NADH oxidase transcription. PLoS Pathog 2023; 19:e1011227. [PMID: 36913374 PMCID: PMC10010549 DOI: 10.1371/journal.ppat.1011227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 02/21/2023] [Indexed: 03/14/2023] Open
Abstract
GntR transcription factor of Streptococcus suis serotype 2 (SS2) is a potential substrate protein of STK, but the regulation mechanisms of GntR phosphorylation are still unclear. This study confirmed that STK phosphorylated GntR in vivo, and in vitro phosphorylation experiments showed that STK phosphorylated GntR at Ser-41. The phosphomimetic strain (GntR-S41E) had significantly reduced lethality in mice and reduced bacterial load in the blood, lung, liver, spleen, and brain of infected mice compared to wild-type (WT) SS2. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) experiments demonstrated that the promoter of nox was bound by GntR. The phosphomimetic protein GntR-S41E cannot bind to the promoter of nox, and the nox transcription levels were significantly reduced in the GntR-S41E mutant compared to WT SS2. The virulence in mice and the ability to resist oxidative stress of the GntR-S41E strain were restored by complementing transcript levels of nox. NOX is an NADH oxidase that catalyzes the oxidation of NADH to NAD+ with the reduction of oxygen to water. We found that NADH is likely accumulated under oxidative stress in the GntR-S41E strain, and higher NADH levels resulted in increased amplified ROS killing. In total, we report GntR phosphorylation could inhibit the transcription of nox, which impaired the ability of SS2 to resist oxidative stress and virulence.
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Affiliation(s)
- Kai Niu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yu Meng
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Mingxing Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Zhe Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
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18
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Xu SQ, Wang X, Xu L, Wang KX, Jiang YH, Zhang FY, Hong Q, He J, Liu SJ, Qiu JG. The MocR family transcriptional regulator DnfR has multiple binding sites and regulates Dirammox gene transcription in Alcaligenes faecalis JQ135. Environ Microbiol 2023; 25:675-688. [PMID: 36527381 DOI: 10.1111/1462-2920.16318] [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: 11/14/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Microbial ammonia oxidation is vital to the nitrogen cycle. A biological process, called Dirammox (direct ammonia oxidation, NH3 →NH2 OH→N2 ), has been recently identified in Alcaligenes ammonioxydans and Alcaligenes faecalis. However, its transcriptional regulatory mechanism has not yet been fully elucidated. The present study characterized a new MocR-like transcription factor DnfR that is involved in the Dirammox process in A. faecalis strain JQ135. The entire dnf cluster was composed of 10 genes and transcribed as five transcriptional units, that is, dnfIH, dnfR, dnfG, dnfABCDE and dnfF. DnfR activates the transcription of dnfIH, dnfG and dnfABCDE genes, and represses its own transcription. The intact 1506-bp dnfR gene was required for activation of Dirammox. Electrophoretic mobility shift assays and DNase I footprinting analyses showed that DnfR has one binding site in the dnfH-dnfR intergenic region and two binding sites in the dnfG-dnfA intergenic region. Three binding sites of DnfR shared a 6-bp repeated conserved sequence 5'-GGTCTG-N17 -GGTCTG-3' which was essential for the transcription of downstream target genes. Cysteine and glutamate act as possible effectors of DnfR to activate the transcription of transcriptional units of dnfG and dnfABCDE, respectively. This study provided new insights in the transcriptional regulation mechanism of Dirammox by DnfR in A. faecalis JQ135.
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Affiliation(s)
- Si-Qiong Xu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xiao Wang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Lu Xu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Ke-Xin Wang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yin-Hu Jiang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Fu-Yin Zhang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Qing Hong
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jian He
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources, and Environmental Microbiology Research Center at Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Ji-Guo Qiu
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
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Chauhan NK, Anand A, Sharma A, Dhiman K, Gosain TP, Singh P, Singh P, Khan E, Chattopadhyay G, Kumar A, Sharma D, Ashish, Sharma TK, Singh R. Structural and Functional Characterization of Rv0792c from Mycobacterium tuberculosis: Identifying Small Molecule Inhibitor against HutC Protein. Microbiol Spectr 2023; 11:e0197322. [PMID: 36507689 PMCID: PMC9927256 DOI: 10.1128/spectrum.01973-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In order to adapt in host tissues, microbial pathogens regulate their gene expression through a variety of transcription factors. Here, we have functionally characterized Rv0792c, a HutC homolog from Mycobacterium tuberculosis. In comparison to the parental strain, a strain of M. tuberculosis with a Rv0792c mutant was compromised for survival upon exposure to oxidative stress and infection in guinea pigs. RNA sequencing analysis revealed that Rv0792c regulates the expression of genes involved in stress adaptation and virulence of M. tuberculosis. Solution small-angle X-ray scattering (SAXS) data-steered model building confirmed that the C-terminal region plays a pivotal role in dimer formation. Systematic evolution of ligands by exponential enrichment (SELEX) resulted in the identification of single-strand DNA (ssDNA) aptamers that can be used as a tool to identify small-molecule inhibitors targeting Rv0792c. Using SELEX and SAXS data-based modeling, we identified residues essential for Rv0792c's aptamer binding activity. In this study, we also identified I-OMe-Tyrphostin as an inhibitor of Rv0792c's aptamer and DNA binding activity. The identified small molecule reduced the growth of intracellular M. tuberculosis in macrophages. The present study thus provides a detailed shape-function characterization of a HutC family of transcription factor from M. tuberculosis. IMPORTANCE Prokaryotes encode a large number of GntR family transcription factors that are involved in various fundamental biological processes, including stress adaptation and pathogenesis. Here, we investigated the structural and functional role of Rv0792c, a HutC homolog from M. tuberculosis. We demonstrated that Rv0792c is essential for M. tuberculosis to adapt to oxidative stress and establish disease in guinea pigs. Using a systematic evolution of ligands by exponential enrichment (SELEX) approach, we identified ssDNA aptamers from a random ssDNA library that bound to Rv0792c protein. These aptamers were thoroughly characterized using biochemical and biophysical assays. Using SAXS, we determined the structural model of Rv0792c in both the presence and absence of the aptamers. Further, using a combination of SELEX and SAXS methodologies, we identified I-OMe-Tyrphostin as a potential inhibitor of Rv0792c. Here we provide a detailed functional characterization of a transcription factor belonging to the HutC family from M. tuberculosis.
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Affiliation(s)
- Neeraj Kumar Chauhan
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Anjali Anand
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Arun Sharma
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Kanika Dhiman
- Institute of Microbial Technologygrid.417641.1, Council of Scientific and Industrial Research, Chandigarh, India
| | - Tannu Priya Gosain
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Prashant Singh
- Institute of Microbial Technologygrid.417641.1, Council of Scientific and Industrial Research, Chandigarh, India
| | - Padam Singh
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Eshan Khan
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indoregrid.450280.b, Indore, India
| | | | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indoregrid.450280.b, Indore, India
| | - Deepak Sharma
- Institute of Microbial Technologygrid.417641.1, Council of Scientific and Industrial Research, Chandigarh, India
| | - Ashish
- Institute of Microbial Technologygrid.417641.1, Council of Scientific and Industrial Research, Chandigarh, India
| | - Tarun Kumar Sharma
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
| | - Ramandeep Singh
- Translational Health Science and Technology Institutegrid.464764.3, Faridabad, Haryana, India
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20
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Deng W, Zheng Z, Chen Y, Yang M, Yan J, Li W, Zeng J, Xie J, Gong S, Zeng H. Deficiency of GntR Family Regulator MSMEG_5174 Promotes Mycobacterium smegmatis Resistance to Aminoglycosides via Manipulating Purine Metabolism. Front Microbiol 2022; 13:919538. [PMID: 35898907 PMCID: PMC9309504 DOI: 10.3389/fmicb.2022.919538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/20/2022] [Indexed: 11/30/2022] Open
Abstract
The increasing incidence of drug-resistant tuberculosis is still an emergency for global public health and a major obstacle to tuberculosis treatment. Therefore, deciphering the novel mechanisms of mycobacterial antibiotic resistance is crucial for combatting the rapid emergence of drug-resistant strains. In this study, we identified an unexpected role of Mycobacterium smegmatis GntR family transcriptional regulator MSMEG_5174 and its homologous gene Mycobacterium tuberculosis Rv1152 in aminoglycoside antibiotic resistance. Deficiency of MSMEG_5174 rendered Mycobacterium smegmatis highly resistant to aminoglycoside antibiotic treatment, and ectopic expression of Rv1152 in MSMEG_5174 mutants restored antibiotic-induced bacterial killing. We further demonstrated that MSMEG_5174 negatively regulates the expression of purine metabolism-related genes and the accumulation of purine metabolites. Moreover, overexpression of xanthine dehydrogenase MSMEG_0871 or xanthine treatment elicited a significant decrease in aminoglycoside antibiotic lethality for Mycobacterium smegmatis. Together, our findings revealed MSMEG_5174 as a metabolic regulator and hint toward unexplored crosstalk between purine metabolism and antibiotic resistance.
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Affiliation(s)
- Wanyan Deng
- The Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Department of Infectious Diseases, Institute for Viral Hepatitis, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- *Correspondence: Wanyan Deng,
| | - Zengzhang Zheng
- The Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Yi Chen
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Department of Infectious Diseases, Institute for Viral Hepatitis, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Maoyi Yang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Department of Infectious Diseases, Institute for Viral Hepatitis, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jun Yan
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Department of Infectious Diseases, Institute for Viral Hepatitis, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wu Li
- The Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Jie Zeng
- Department of Respiratory Medicine, The First People’s Hospital of Yunnan Province, Kunming, China
- Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
| | - Jianping Xie
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-Environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Institute of Modern Biopharmaceuticals, Southwest University, Chongqing, China
| | - Sitang Gong
- The Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- Sitang Gong,
| | - Huasong Zeng
- The Joint Center for Infection and Immunity, Guangzhou Institute of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- Huasong Zeng,
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21
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Anderssen S, Naômé A, Jadot C, Brans A, Tocquin P, Rigali S. AURTHO: Autoregulation of transcription factors as facilitator of cis-acting element discovery. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194847. [PMID: 35901946 DOI: 10.1016/j.bbagrm.2022.194847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/04/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Transcriptional regulation is key in bacteria for providing an adequate response in time and space to changing environmental conditions. However, despite decades of research, the binding sites and therefore the target genes and the function of most transcription factors (TFs) remain unknown. Filling this gap in knowledge through conventional methods represents a colossal task which we demonstrate here can be significantly facilitated by a widespread feature in transcriptional control: the autoregulation of TFs implying that the yet unknown transcription factor binding site (TFBS) is neighboring the TF itself. In this work, we describe the "AURTHO" methodology (AUtoregulation of oRTHOlogous transcription factors), consisting of analyzing upstream regions of orthologous TFs in order to uncover their associated TFBSs. AURTHO enabled the de novo identification of novel TFBSs with an unprecedented improvement in terms of quantity and reliability. DNA-protein interaction studies on a selection of candidate cis-acting elements yielded an >90 % success rate, demonstrating the efficacy of AURTHO at highlighting true TF-TFBS couples and confirming the identification in a near future of a plethora of TFBSs across all bacterial species.
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Affiliation(s)
- Sinaeda Anderssen
- InBioS - Center for Protein Engineering, University of Liège, B-4000 Liège, Belgium
| | - Aymeric Naômé
- InBioS - Center for Protein Engineering, University of Liège, B-4000 Liège, Belgium; HEDERA 22, Boulevard du Rectorat 27b, B-4000 Liège, Belgium
| | - Cédric Jadot
- InBioS - Center for Protein Engineering, University of Liège, B-4000 Liège, Belgium
| | - Alain Brans
- InBioS - Center for Protein Engineering, University of Liège, B-4000 Liège, Belgium
| | - Pierre Tocquin
- HEDERA 22, Boulevard du Rectorat 27b, B-4000 Liège, Belgium; InBioS - PhytoSystems, University of Liège, B-4000 Liège, Belgium
| | - Sébastien Rigali
- InBioS - Center for Protein Engineering, University of Liège, B-4000 Liège, Belgium; HEDERA 22, Boulevard du Rectorat 27b, B-4000 Liège, Belgium.
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22
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Xu X, Yan Y, Huang J, Zhang Z, Wang Z, Wu M, Liang H. Regulation of uric acid and glyoxylate metabolism by UgmR protein in Pseudomonas aeruginosa. Environ Microbiol 2022; 24:3242-3255. [PMID: 35702827 DOI: 10.1111/1462-2920.16088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 11/30/2022]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa has evolved several systems to adapt to complex environments. The GntR family proteins play important roles in the regulation of metabolic processes and bacterial pathogenesis. In this study, we uncovered that the gene clusters of PA1513-PA1518 and PA1498-PA1502 in P. aeruginosa are required for uric acid and glyoxylate metabolism, respectively. We also identified a GntR family regulator UgmR that is involved in regulation of uric acid and glyoxylate metabolism. Promoter activity measurement and biochemical assays revealed that the UgmR directly represses the transcriptional activity of PA1513-PA1518 and PA1498-PA1502, and this inhibition was relieved by the addition of uric acid. Importantly, further experiments showed that UgmR also participates in the glyoxylate shunt. Collectively, these findings contribute to a better understanding of the UgmR factor involved in uric acid and glyoxylate metabolism, which provide insights into the complex metabolic pathways in P. aeruginosa. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Xuejie Xu
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
| | - Yunfang Yan
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
| | - Jiadai Huang
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, SAR, China
| | - Zihao Zhang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China
| | - Zhihan Wang
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND
| | - Min Wu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND
| | - Haihua Liang
- Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, ShaanXi, China.,College of Medicine, Southern University of Science and Technology, Shenzhen, China
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23
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Investigating a putative transcriptional regulatory protein encoded by Rv1719 gene of Mycobacterium tuberculosis. Protein J 2022; 41:424-433. [PMID: 35715720 DOI: 10.1007/s10930-022-10062-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2022] [Indexed: 10/18/2022]
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, demonstrates immense plasticity with which it adapts to a highly dynamic and hostile host environment. This is facilitated by a web of signalling pathways constantly modulated by a multitude of proteins that regulate the flow of genetic information inside the pathogen. Transcription factors (TFs) belongs to one such family of proteins that modulate the signalling by regulating the abundance of proteins at the transcript level. In the current study, we have characterized the putative transcriptional regulatory protein encoded by the Rv1719 gene of Mycobacterium tuberculosis. This TF belongs to the IclR family of proteins with orthologs found in both bacterial and archaeal species. We cloned the Rv1719 gene into the pET28a expression vector and performed heterologous expression of the recombinant protein with E coli as the host. Further, optimization of the purification protocol by affinity chromatography and characterization of proteins for their functional viability has been demonstrated using various biochemical and/or biophysical approaches. Scale-up of purification yielded approximately 30 mg of ~ 28 kDa protein per litre of culture. In-silico protein domain analysis of Rv1719 protein predicted the presence of the helix-turn-helix (HTH) domain suggesting its ability to bind DNA sequence and modulate transcription; a hallmark of a transcriptional regulatory protein. Further, by performing electrophoretic mobility shift assay (EMSA) we demonstrated that the protein binds to a specific DNA fragment harboring the probable binding site of one of the predicted promoters.
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24
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Toyoda K, Sugaya R, Domon A, Suda M, Hiraga K, Inui M. Identification and Molecular Characterization of the Operon Required for L-Asparagine Utilization in Corynebacterium glutamicum. Microorganisms 2022; 10:1002. [PMID: 35630445 PMCID: PMC9145765 DOI: 10.3390/microorganisms10051002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/30/2022] [Accepted: 05/07/2022] [Indexed: 11/25/2022] Open
Abstract
Understanding the metabolic pathways of amino acids and their regulation is important for the rational metabolic engineering of amino acid production. The catabolic pathways of L-asparagine and L-aspartate are composed of transporters for amino acid uptake and asparaginase and aspartase, which are involved in the sequential deamination to fumarate. However, knowledge of the catabolic genes for asparagine in bacteria of the Actinobacteria class has been limited. In this study, we identified and characterized the ans operon required for L-Asn catabolism in Corynebacterium glutamicum R. The operon consisted of genes encoding a transcriptional regulator (AnsR), asparaginase (AnsA2), aspartase (AspA2), and permease (AnsP). The enzymes and permease encoded in the operon were shown to be essential for L-Asn utilization, but another asparaginase, AnsA1, and aspartase, AspA1, were not essential. Expression analysis revealed that the operon was induced in response to extracellular L-Asn and was transcribed as a leaderless mRNA. The DNA-binding assay demonstrated that AnsR acted as a transcriptional repressor of the operon by binding to the inverted repeat at its 5'-end region. The AnsR binding was inhibited by L-Asn. This study provides insights into the functions and regulatory mechanisms of similar operon-like clusters in related bacteria.
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Affiliation(s)
- Koichi Toyoda
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa 619-0292, Japan; (K.T.); (M.S.); (K.H.)
| | - Riki Sugaya
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan; (R.S.); (A.D.)
| | - Akihiro Domon
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan; (R.S.); (A.D.)
| | - Masako Suda
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa 619-0292, Japan; (K.T.); (M.S.); (K.H.)
| | - Kazumi Hiraga
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa 619-0292, Japan; (K.T.); (M.S.); (K.H.)
| | - Masayuki Inui
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa 619-0292, Japan; (K.T.); (M.S.); (K.H.)
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan; (R.S.); (A.D.)
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25
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Li Y, Sun W, Wang Q, Yu Y, Wan Y, Zhou K, Guo R, Han X, Chen Z, Fang W, Jiang W. The GntR-like transcriptional regulator HutC involved in motility, biofilm-forming ability, and virulence in Vibrio parahaemolyticus. Microb Pathog 2022; 167:105546. [DOI: 10.1016/j.micpath.2022.105546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 06/12/2021] [Accepted: 04/15/2022] [Indexed: 12/19/2022]
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26
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Li C, Wang J, Lin H, Zhang Y, Ma Z, Bechthold A, Yu X. Protein X0P338, a GntR-type pleiotropic regulator for morphological differentiation and secondary metabolites production in Streptomyces diastatochromogenes 1628. J Basic Microbiol 2022; 62:788-800. [PMID: 35485240 DOI: 10.1002/jobm.202200086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/08/2022] [Accepted: 04/15/2022] [Indexed: 11/07/2022]
Abstract
The nucleoside antibiotic, toyocamycin (TM) exhibits excellent potent activity against several phytopathogenic fungi. Despite of its importance, little is known about key factors regulating TM biosynthesis and morphological differentiation in S. diastatochromogenes 1628. Based on proteomics data obtained from the analysis between wild-type (WT) S. diastatochromogenes 1628 strain and mutant strain 1628-T62 having a low-yield of TM, we observed that the differentially expressed protein, X0P338, which was proposed to be a regulator of the GntR-family, exhibited a higher expression level in S. diastatochromogenes 1628. Therefore, in this study, to explore whether protein X0P338 was involved in morphological differentiation and biosynthesis of secondary metabolites, especially TM, the gene called the gntR sd -encoding protein X0P338 was cloned and over-expressed in WT strain 1628 and mutant strain 1628-T62, respectively. The results indicated that the over-expression of gntR sd enhanced TM production in both strain 1628 (120.6 mg/L vs. 306.6 mg/L) and strain 1628-T62 (15.6 mg/L vs. 258.9 mg/L). Besides, the over-expression of gntR sd had positive and negative effects on morphological differentiation in strain 1628 and strain 1628-T62, respectively. The results also showed opposite effects on tetraene macrolide production during the over-expression of gntR sd in strain 1628 and strain 1628-T62. Moreover, transcription levels of genes involved in morphological differentiation and secondary metabolites production were affected by the over-expression of gntR sd gene, both in strain 1628 and strain 1628-T62. These results confirm that X0P338 as a GntR-type pleiotropic regulator that regulates the morphological differentiation and biosynthesis of secondary metabolites, and especially has a positive effect on TM biosynthesis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Chouqiang Li
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, 310018, China
| | - Juan Wang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, 310018, China
| | - Hengyi Lin
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, 310018, China
| | - Yongyong Zhang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, 310018, China
| | | | - Andreas Bechthold
- University of Freiburg, Institute for Pharmaceutical Sciences, Pharmaceutical Biology and Biotechnology, Freiburg, Germany
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27
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Gonococcal Clinical Strains Bearing a Common gdhR Single Nucleotide Polymorphism That Results in Enhanced Expression of the Virulence Gene lctP Frequently Possess a mtrR Promoter Mutation That Decreases Antibiotic Susceptibility. mBio 2022; 13:e0027622. [PMID: 35258329 PMCID: PMC9040798 DOI: 10.1128/mbio.00276-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
GdhR is a transcriptional repressor of the virulence factor gene lctP, which encodes a unique l-lactate permease that has been linked to pathogenesis of Neisseria gonorrhoeae, and loss of gdhR can confer increased fitness of gonococci in a female mouse model of lower genital tract infection. In this work, we identified a single nucleotide polymorphism (SNP) in gdhR, which is often present in both recent and historical gonococcal clinical strains and results in a proline (P)-to-serine (S) change at amino acid position 6 (P6S) of GdhR. This mutation (gdhR6) was found to reduce GdhR transcriptional repression at lctP in gonococcal strains containing the mutant protein compared to wild-type GdhR. By using purified recombinant proteins and in vitro DNA-binding and cross-linking experiments, we found that gdhR6 impairs the DNA-binding activity of GdhR at lctP without an apparent effect on protein oligomerization. By analyzing a panel of U.S. (from 2017 to 2018) and Danish (1928 to 2013) clinical isolates, we observed a statistical association between gdhR6 and the previously described adenine deletion in the promoter of mtrR (mtrR-P A-del), encoding the repressor (MtrR) of the mtrCDE operon that encodes the MtrCDE multidrug efflux pump that can export antibiotics, host antimicrobials, and biocides. The frequent association of gdhR6 with the mtrR promoter mutation in these clinical isolates suggests that it has persisted in this genetic background to enhance lctP expression, thereby promoting virulence.
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28
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Lassak J, Sieber A, Hellwig M. Exceptionally versatile take II: post-translational modifications of lysine and their impact on bacterial physiology. Biol Chem 2022; 403:819-858. [PMID: 35172419 DOI: 10.1515/hsz-2021-0382] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/05/2022] [Indexed: 01/16/2023]
Abstract
Among the 22 proteinogenic amino acids, lysine sticks out due to its unparalleled chemical diversity of post-translational modifications. This results in a wide range of possibilities to influence protein function and hence modulate cellular physiology. Concomitantly, lysine derivatives form a metabolic reservoir that can confer selective advantages to those organisms that can utilize it. In this review, we provide examples of selected lysine modifications and describe their role in bacterial physiology.
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Affiliation(s)
- Jürgen Lassak
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Großhaderner Straße 2-4, D-82152 Planegg, Germany
| | - Alina Sieber
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Großhaderner Straße 2-4, D-82152 Planegg, Germany
| | - Michael Hellwig
- Technische Universität Braunschweig - Institute of Food Chemistry, Schleinitzstraße 20, D-38106 Braunschweig, Germany
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29
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Augustiniene E, Malys N. Identification and characterization of L- and D-lactate-inducible systems from Escherichia coli MG1655, Cupriavidus necator H16 and Pseudomonas species. Sci Rep 2022; 12:2123. [PMID: 35136142 PMCID: PMC8827060 DOI: 10.1038/s41598-022-06028-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 01/17/2022] [Indexed: 12/22/2022] Open
Abstract
Lactic acid is an important platform chemical used for the production of various compounds including polylactic acid (PLA). Optically pure L- and D-lactic acids are required to obtain high quality PLA. To advance the development and selection of microbial strains for improved production of lactic acid enantiomers, a high-throughput screening, dynamic pathway control, or real-time monitoring are often applied. Inducible gene expression systems and their application in the genetically encoded biosensors contribute to the development of these techniques and are important devices for the advancement of lactic acid biotechnology. Here, we identify and characterize eleven lactate-inducible systems from Escherichia coli, Cupriavidus necator, and Pseudomonas spp. The specificity and dynamics of these systems in response to L- and D-lactate, or structurally similar compounds are investigated. We demonstrate that the inducible systems EcLldR/PlldP and CnGntR/PH16_RS19190 respond only to the L-lactate, exhibiting approximately 19- and 24-fold induction, respectively. Despite neither of the examined bacteria possess the D-lactate-specific inducible system, the PaPdhR/PlldP and PfPdhR/PlldP are induced approximately 37- and 366-fold, respectively, by D-lactate and can be used for developing biosensor with improved specificity. The findings of this study provide an insight into understanding of L- and D-lactate-inducible systems that can be employed as sensing and tuneable devices in synthetic biology.
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Affiliation(s)
- Ernesta Augustiniene
- Bioprocess Research Centre, Faculty of Chemical Technology, Kaunas University of Technology, Radvilėnų pl. 19, Kaunas, LT-50254, Lithuania
| | - Naglis Malys
- Bioprocess Research Centre, Faculty of Chemical Technology, Kaunas University of Technology, Radvilėnų pl. 19, Kaunas, LT-50254, Lithuania. .,Department of Organic Chemistry, Faculty of Chemical Technology, Kaunas University of Technology, Radvilėnų pl. 19, Kaunas, LT-50254, Lithuania.
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30
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Genetic Foundations of Direct Ammonia Oxidation (Dirammox) to N 2 and MocR-like Transcriptional Regulator DnfR in Alcaligenes faecalis JQ135. Appl Environ Microbiol 2022; 88:e0226121. [PMID: 35108103 DOI: 10.1128/aem.02261-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ammonia oxidation is an important process of both the natural nitrogen cycle and nitrogen removal from engineered ecosystems. Recently, a new ammonia oxidation pathway termed Dirammox (direct ammonia oxidation, NH3→NH2OH→N2) has been identified in Alcaligenes ammonioxydans. However, whether Dirammox is present in other microbes and its genetic regulation remains unknown. In this study, it was found that the metabolically versatile bacterium Alcaligenes faecalis strain JQ135 could efficiently convert ammonia into N2 via NH2OH under aerobic conditions. Genetic deletion and complementation results suggest that dnfABC is responsible for the ammonia oxidation to N2 in this strain. Strain JQ135 also employs aerobic denitrification, mainly producing N2O and trace amounts of N2 with nitrite as sole nitrogen source. Deletion of genes nirK and nosZ that are essential for denitrification did not impair the capability of JQ135 to oxidize ammonia to N2 (i.e., Dirammox is independent of denitrification). Furthermore, it was also demonstrated that pod (which encodes pyruvic oxime dioxygenase) was not involved in Dirammox and AFA_16745 (which was previously annotated as ammonia monooxygenase and is widespread in heterotrophic bacteria) was not an ammonia monooxygenase. The MocR-family transcriptional regulator DnfR was characterized as an activator of the dnfABC operon with the binding motif 5'-TGGTCTGT-3' in the promotor region. Bioinformatic survey showed that homologs to dnf genes are widely distributed in heterotrophic bacteria. In conclusion, this work demonstrates that besides A. ammonioxydans, Dirammox also occurs in other bacteria, and is regulated by the MocR-family transcriptional regulator DnfR. Importance Microbial ammonia oxidation is a key and rate-limiting step of the nitrogen cycle. Three previous known ammonia oxidation pathways (i.e., nitrification, anaerobic ammonia oxidation (Anammox), and complete ammonia oxidation (Comammox)) are mediated by autotrophic microbes. However, the genetic foundations of ammonia oxidation by heterotrophic microorganisms have not been investigated in depth. Recently, a previously unknown pathway, termed direct ammonia oxidation to N2 (Dirammox), has been identified in the heterotrophic bacterium Alcaligenes ammonioxydans HO-1. This paper shows that in the metabolically versatile bacterium Alcaligenes faecalis JQ135, the Dirammox pathway is mediated by dnf genes, which are independent of the denitrification pathway. Bioinformatic survey suggests that homologs to dnf genes are widely distributed in bacteria. These findings enhance the understanding of the molecular mechanisms of heterotrophic ammonia oxidation to N2.
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31
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Hermann L, Dempwolff F, Steinchen W, Freibert SA, Smits SHJ, Seubert A, Bremer E. The MocR/GabR Ectoine and Hydroxyectoine Catabolism Regulator EnuR: Inducer and DNA Binding. Front Microbiol 2022; 12:764731. [PMID: 35003002 PMCID: PMC8739950 DOI: 10.3389/fmicb.2021.764731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022] Open
Abstract
The compatible solutes ectoine and 5-hydroxyectoine are widely synthesized by bacteria as osmostress protectants. These nitrogen-rich tetrahydropyrimidines can also be exploited as nutrients by microorganisms. Many ectoine/5-hydroxyectoine catabolic gene clusters are associated with a regulatory gene (enuR: ectoine nutrient utilization regulator) encoding a repressor protein belonging to the MocR/GabR sub-family of GntR-type transcription factors. Focusing on EnuR from the marine bacterium Ruegeria pomeroyi, we show that the dimerization of EnuR is mediated by its aminotransferase domain. This domain can fold independently from its amino-terminal DNA reading head and can incorporate pyridoxal-5′-phosphate (PLP) as cofactor. The covalent attachment of PLP to residue Lys302 of EnuR was proven by mass-spectrometry. PLP interacts with system-specific, ectoine and 5-hydroxyectoine-derived inducers: alpha-acetyldiaminobutyric acid (alpha-ADABA), and hydroxy-alpha-acetyldiaminobutyric acid (hydroxy-alpha-ADABA), respectively. These inducers are generated in cells actively growing with ectoines as sole carbon and nitrogen sources, by the EutD hydrolase and targeted metabolic analysis allowed their detection. EnuR binds these effector molecules with affinities in the low micro-molar range. Studies addressing the evolutionary conservation of EnuR, modelling of the EnuR structure, and docking experiments with the inducers provide an initial view into the cofactor and effector binding cavity. In this cavity, the two high-affinity inducers for EnuR, alpha-ADABA and hydroxy-alpha-ADABA, are positioned such that their respective primary nitrogen group can chemically interact with PLP. Purified EnuR bound with micro-molar affinity to a 48 base pair DNA fragment containing the sigma-70 type substrate-inducible promoter for the ectoine/5-hydroxyectoine importer and catabolic gene cluster. Consistent with the function of EnuR as a repressor, the core elements of the promoter overlap with two predicted EnuR operators. Our data lend themselves to a straightforward regulatory model for the initial encounter of EnuR-possessing ectoine/5-hydroxyectoine consumers with environmental ectoines and for the situation when the external supply of these compounds has been exhausted by catabolism.
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Affiliation(s)
- Lucas Hermann
- Faculty of Biology, Philipps-University Marburg, Marburg, Germany.,Department of Biochemistry and Synthetic Metabolism, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Felix Dempwolff
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Wieland Steinchen
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Sven-Andreas Freibert
- Department of Medicine, Institute for Cytobiology and Cytopathology, and SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany.,Center for Structural Studies (CSS), Faculty of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Faculty of Biology, Philipps-University Marburg, Marburg, Germany.,SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
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32
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Feng Y, Gu D, Wang Z, Lu C, Fan J, Zhou J, Wang R, Su X. Comprehensive evaluation and analysis of the salinity stress response mechanisms based on transcriptome and metabolome of Staphylococcus aureus. Arch Microbiol 2021; 204:28. [PMID: 34921629 DOI: 10.1007/s00203-021-02624-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 10/03/2021] [Accepted: 10/07/2021] [Indexed: 10/19/2022]
Abstract
Staphylococcus aureus possesses an extraordinary ability to deal with a wide range of osmotic pressure. This study performed transcriptomic and metabolomic analyses on the potential mechanism of gradient salinity stress adaptation in S. aureus ZS01. The results revealed that CPS biosynthetic protein genes were candidate target genes for directly regulating the phenotypic changes of biofilm. Inositol phosphate metabolism was downregulated to reduce the conversion of functional molecules. The gluconeogenesis pathway and histidine synthesis were downregulated to reduce the production of endogenous glucose. The pyruvate metabolism pathway was upregulated to promote the accumulation of succinate. TCA cycle metabolism pathway was downregulated to reduce unnecessary energy loss. L-Proline was accumulated to regulate osmotic pressure. Therefore, these self-protection mechanisms can protect cells from hypertonic environments and help them focus on survival. In addition, we identified ten hub genes. The findings will aid in the prevention and treatment strategies of S. aureus infections.
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Affiliation(s)
- Ying Feng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China.,College of Life Sciences, Tonghua Normal University, Tonghua, China.,School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China
| | - Dizhou Gu
- College of Life Sciences, Tonghua Normal University, Tonghua, China
| | - Ziyan Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China.,School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China
| | - Chenyang Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China.,School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China
| | - Jingfeng Fan
- National Marine Environmental Monitoring Center, Dalian, China
| | - Jun Zhou
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China.,School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China
| | - Rixin Wang
- School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China.
| | - Xiurong Su
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China. .,School of Marine Sciences, Ningbo University, 169 Qixing South Road, Ningbo City, 315211, Zhejiang Province, China.
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Abeywickrama TD, Perera IC. In Silico Characterization and Virtual Screening of GntR/HutC Family Transcriptional Regulator MoyR: A Potential Monooxygenase Regulator in Mycobacterium tuberculosis. BIOLOGY 2021; 10:biology10121241. [PMID: 34943156 PMCID: PMC8698889 DOI: 10.3390/biology10121241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/31/2022]
Abstract
Simple Summary In an era where the world faces new diseases and pathogens, another emerging challenge is neglected pathogens becoming more notorious. Transcriptional regulators play a vital role in the pathogenesis and survival of these pathogens. Hence, characterizing transcriptional regulators, either in vitro or in silico, is of great importance. Here, we present the first structural characterization of a GntR/HutC regulator in Mycobacterium tuberculosis via in silico methods. We have suggested its possible role and potential as a drug target as well as identified possible drug leads that can be used for further improvements. Abstract Mycobacterium tuberculosis is a well-known pathogen due to the emergence of drug resistance associated with it, where transcriptional regulators play a key role in infection, colonization and persistence. The genome of M. tuberculosis encodes many transcriptional regulators, and here we report an in-depth in silico characterization of a GntR regulator: MoyR, a possible monooxygenase regulator. Homology modelling provided a reliable structure for MoyR, showing homology with a HutC regulator DasR from Streptomyces coelicolor. In silico physicochemical analysis revealed that MoyR is a cytoplasmic protein with higher thermal stability and higher pI. Four highly probable binding pockets were determined in MoyR and the druggability was higher in the orthosteric binding site consisting of three conserved critical residues: TYR179, ARG223 and GLU234. Two highly conserved leucine residues were identified in the effector-binding region of MoyR and other HutC homologues, suggesting that these two residues can be crucial for structure stability and oligomerization. Virtual screening of drug leads resulted in four drug-like compounds with greater affinity to MoyR with potential inhibitory effects for MoyR. Our findings support that this regulator protein can be valuable as a therapeutic target that can be used for developing drug leads.
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Pawlik KJ, Zelkowski M, Biernacki M, Litwinska K, Jaworski P, Kotowska M. GntR-like SCO3932 Protein Provides a Link between Actinomycete Integrative and Conjugative Elements and Secondary Metabolism. Int J Mol Sci 2021; 22:ijms222111867. [PMID: 34769298 PMCID: PMC8584621 DOI: 10.3390/ijms222111867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 01/16/2023] Open
Abstract
Streptomyces bacteria produce a plethora of secondary metabolites including the majority of medically important antibiotics. The onset of secondary metabolism is correlated with morphological differentiation and controlled by a complex regulatory network involving numerous regulatory proteins. Control over these pathways at the molecular level has a medical and industrial importance. Here we describe a GntR-like DNA binding transcription factor SCO3932, encoded within an actinomycete integrative and conjugative element, which is involved in the secondary metabolite biosynthesis regulation. Affinity chromatography, electrophoresis mobility shift assay, footprinting and chromatin immunoprecipitation experiments revealed, both in vitro and in vivo, SCO3932 binding capability to its own promoter region shared with the neighboring gene SCO3933, as well as promoters of polyketide metabolite genes, such as cpkD, a coelimycin biosynthetic gene, and actII-orf4—an activator of actinorhodin biosynthesis. Increased activity of SCO3932 target promoters, as a result of SCO3932 overproduction, indicates an activatory role of this protein in Streptomyces coelicolor A3(2) metabolite synthesis pathways.
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Bandera AM, Bartho J, Lammens K, Drexler DJ, Kleinschwärzer J, Hopfner KP, Witte G. BusR senses bipartite DNA binding motifs by a unique molecular ruler architecture. Nucleic Acids Res 2021; 49:10166-10177. [PMID: 34432045 PMCID: PMC8517857 DOI: 10.1093/nar/gkab736] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 07/27/2021] [Accepted: 08/12/2021] [Indexed: 12/18/2022] Open
Abstract
The cyclic dinucleotide second messenger c-di-AMP is a major player in regulation of potassium homeostasis and osmolyte transport in a variety of bacteria. Along with various direct interactions with proteins such as potassium channels, the second messenger also specifically binds to transcription factors, thereby altering the processes in the cell on the transcriptional level. We here describe the structural and biochemical characterization of BusR from the human pathogen Streptococcus agalactiae. BusR is a member of a yet structurally uncharacterized subfamily of the GntR family of transcription factors that downregulates transcription of the genes for the BusA (OpuA) glycine-betaine transporter upon c-di-AMP binding. We report crystal structures of full-length BusR, its apo and c-di-AMP bound effector domain, as well as cryo-EM structures of BusR bound to its operator DNA. Our structural data, supported by biochemical and biophysical data, reveal that BusR utilizes a unique domain assembly with a tetrameric coiled-coil in between the binding platforms, serving as a molecular ruler to specifically recognize a 22 bp separated bipartite binding motif. Binding of c-di-AMP to BusR induces a shift in equilibrium from an inactivated towards an activated state that allows BusR to bind the target DNA, leading to transcriptional repression.
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Affiliation(s)
- Adrian M Bandera
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - Joseph Bartho
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - Katja Lammens
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - David Jan Drexler
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - Jasmin Kleinschwärzer
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - Karl-Peter Hopfner
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
| | - Gregor Witte
- Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 München, Germany
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Purtov YA, Tishchenko SV, Nikulin AD. Modeling the Interaction of the UxuR–ExuR Heterodimer with the Components of the Metabolic Pathway of Escherichia coli for Hexuronate Utilization. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921050201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Hasan MK, Dhungel BA, Govind R. Characterization of an operon required for growth on cellobiose in Clostridioides difficile. MICROBIOLOGY-SGM 2021; 167. [PMID: 34410904 DOI: 10.1099/mic.0.001079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cellobiose metabolism is linked to the virulence properties in numerous bacterial pathogens. Here, we characterized a putative cellobiose PTS operon of Clostridiodes difficile to investigate the role of cellobiose metabolism in C. difficile pathogenesis. Our gene knockout experiments demonstrated that the putative cellobiose operon enables uptake of cellobiose into C. difficile and allows growth when cellobiose is provided as the sole carbon source in minimal medium. Additionally, using reporter gene fusion assays and DNA pulldown experiments, we show that its transcription is regulated by CelR, a novel transcriptional repressor protein, which directly binds to the upstream region of the cellobiose operon to control its expression. We have also identified cellobiose metabolism to play a significant role in C. difficile physiology as observed by the reduction of sporulation efficiency when cellobiose uptake was compromised in the mutant strain. In corroboration to in vitro study findings, our in vivo hamster challenge experiment showed a significant reduction of pathogenicity by the cellobiose mutant strain in both the primary and the recurrent infection model - substantiating the role of cellobiose metabolism in C. difficile pathogenesis.
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Affiliation(s)
- Md Kamrul Hasan
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | | | - Revathi Govind
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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38
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Kang Z, Zhang M, Gao K, Zhang W, Meng W, Liu Y, Xiao D, Guo S, Ma C, Gao C, Xu P. An L-2-hydroxyglutarate biosensor based on specific transcriptional regulator LhgR. Nat Commun 2021; 12:3619. [PMID: 34131130 PMCID: PMC8206213 DOI: 10.1038/s41467-021-23723-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/13/2021] [Indexed: 11/09/2022] Open
Abstract
l-2-Hydroxyglutarate (l-2-HG) plays important roles in diverse physiological processes, such as carbon starvation response, tumorigenesis, and hypoxic adaptation. Despite its importance and intensively studied metabolism, regulation of l-2-HG metabolism remains poorly understood and none of regulator specifically responded to l-2-HG has been identified. Based on bacterial genomic neighborhood analysis of the gene encoding l-2-HG oxidase (LhgO), LhgR, which represses the transcription of lhgO in Pseudomonas putida W619, is identified in this study. LhgR is demonstrated to recognize l-2-HG as its specific effector molecule, and this allosteric transcription factor is then used as a biorecognition element to construct an l-2-HG-sensing FRET sensor. The l-2-HG sensor is able to conveniently monitor the concentrations of l-2-HG in various biological samples. In addition to bacterial l-2-HG generation during carbon starvation, biological function of the l-2-HG dehydrogenase and hypoxia induced l-2-HG accumulation are also revealed by using the l-2-HG sensor in human cells. L-2-hydroxyglutarate (L-2-HG) is an important metabolite but its regulation is poorly understood. Here the authors report an L-2-HG FRET biosensor based on the allosteric transcription factor, LhgR, to monitor L-2-HG in cells and biological samples.
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Affiliation(s)
- Zhaoqi Kang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Manman Zhang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Department of Radiobiology, Institute of Radiation Medicine of Chinese Academy of Medical Science and Peking Union Medical College, Tianjin, People's Republic of China
| | - Kaiyu Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Wen Zhang
- Center for Gene and Immunotherapy, The Second Hospital of Shandong University, Jinan, People's Republic of China
| | - Wensi Meng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Yidong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Dan Xiao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Shiting Guo
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Cuiqing Ma
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China
| | - Chao Gao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, People's Republic of China.
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
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Suvorova IA, Gelfand MS. Comparative Analysis of the IclR-Family of Bacterial Transcription Factors and Their DNA-Binding Motifs: Structure, Positioning, Co-Evolution, Regulon Content. Front Microbiol 2021; 12:675815. [PMID: 34177859 PMCID: PMC8222616 DOI: 10.3389/fmicb.2021.675815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/14/2021] [Indexed: 11/13/2022] Open
Abstract
The IclR-family is a large group of transcription factors (TFs) regulating various biological processes in diverse bacteria. Using comparative genomics techniques, we have identified binding motifs of IclR-family TFs, reconstructed regulons and analyzed their content, finding co-occurrences between the regulated COGs (clusters of orthologous genes), useful for future functional characterizations of TFs and their regulated genes. We describe two main types of IclR-family motifs, similar in sequence but different in the arrangement of the half-sites (boxes), with GKTYCRYW3-4RYGRAMC and TGRAACAN1-2TGTTYCA consensuses, and also predict that TFs in 32 orthologous groups have binding sites comprised of three boxes with alternating direction, which implies two possible alternative modes of dimerization of TFs. We identified trends in site positioning relative to the translational gene start, and show that TFs in 94 orthologous groups bind tandem sites with 18-22 nucleotides between their centers. We predict protein-DNA contacts via the correlation analysis of nucleotides in binding sites and amino acids of the DNA-binding domain of TFs, and show that the majority of interacting positions and predicted contacts are similar for both types of motifs and conform well both to available experimental data and to general protein-DNA interaction trends.
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Affiliation(s)
- Inna A Suvorova
- Institute for Information Transmission Problems of Russian Academy of Sciences (The Kharkevich Institute), Moscow, Russia
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems of Russian Academy of Sciences (The Kharkevich Institute), Moscow, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
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40
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Almeida BC, Kaczmarek JA, Figueiredo PR, Prather KLJ, Carvalho ATP. Transcription factor allosteric regulation through substrate coordination to zinc. NAR Genom Bioinform 2021; 3:lqab033. [PMID: 33987533 PMCID: PMC8092373 DOI: 10.1093/nargab/lqab033] [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: 11/17/2020] [Revised: 03/30/2021] [Accepted: 04/08/2021] [Indexed: 11/14/2022] Open
Abstract
The development of new synthetic biology circuits for biotechnology and medicine requires deeper mechanistic insight into allosteric transcription factors (aTFs). Here we studied the aTF UxuR, a homodimer of two domains connected by a highly flexible linker region. To explore how ligand binding to UxuR affects protein dynamics we performed molecular dynamics simulations in the free protein, the aTF bound to the inducer D-fructuronate or the structural isomer D-glucuronate. We then validated our results by constructing a sensor plasmid for D-fructuronate in Escherichia coli and performed site-directed mutagenesis. Our results show that zinc coordination is necessary for UxuR function since mutation to alanines prevents expression de-repression by D-fructuronate. Analyzing the different complexes, we found that the disordered linker regions allow the N-terminal domains to display fast and large movements. When the inducer is bound, UxuR can sample an open conformation with a more pronounced negative charge at the surface of the N-terminal DNA binding domains. In opposition, in the free and D-glucuronate bond forms the protein samples closed conformations, with a more positive character at the surface of the DNA binding regions. These molecular insights provide a new basis to harness these systems for biological systems engineering.
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Affiliation(s)
- Beatriz C Almeida
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
| | - Jennifer A Kaczmarek
- MIT-Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Pedro R Figueiredo
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
| | - Kristala L J Prather
- MIT-Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alexandra T P Carvalho
- CNC-Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
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Horne CR, Venugopal H, Panjikar S, Wood DM, Henrickson A, Brookes E, North RA, Murphy JM, Friemann R, Griffin MDW, Ramm G, Demeler B, Dobson RCJ. Mechanism of NanR gene repression and allosteric induction of bacterial sialic acid metabolism. Nat Commun 2021; 12:1988. [PMID: 33790291 PMCID: PMC8012715 DOI: 10.1038/s41467-021-22253-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 03/03/2021] [Indexed: 12/20/2022] Open
Abstract
Bacteria respond to environmental changes by inducing transcription of some genes and repressing others. Sialic acids, which coat human cell surfaces, are a nutrient source for pathogenic and commensal bacteria. The Escherichia coli GntR-type transcriptional repressor, NanR, regulates sialic acid metabolism, but the mechanism is unclear. Here, we demonstrate that three NanR dimers bind a (GGTATA)3-repeat operator cooperatively and with high affinity. Single-particle cryo-electron microscopy structures reveal the DNA-binding domain is reorganized to engage DNA, while three dimers assemble in close proximity across the (GGTATA)3-repeat operator. Such an interaction allows cooperative protein-protein interactions between NanR dimers via their N-terminal extensions. The effector, N-acetylneuraminate, binds NanR and attenuates the NanR-DNA interaction. The crystal structure of NanR in complex with N-acetylneuraminate reveals a domain rearrangement upon N-acetylneuraminate binding to lock NanR in a conformation that weakens DNA binding. Our data provide a molecular basis for the regulation of bacterial sialic acid metabolism. The GntR superfamily is one of the largest families of transcription factors in prokaryotes. Here the authors combine biophysical analysis and structural biology to dissect the mechanism by which NanR — a GntR-family regulator — binds to its promoter to repress the transcription of genes necessary for sialic acid metabolism.
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Affiliation(s)
- Christopher R Horne
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Hariprasad Venugopal
- Clive and Vera Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia
| | - Santosh Panjikar
- Australian Synchrotron, ANSTO, Clayton, VIC, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - David M Wood
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada
| | - Emre Brookes
- Department of Chemistry, University of Montana, Missoula, MT, USA
| | - Rachel A North
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - James M Murphy
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Rosmarie Friemann
- Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Michael D W Griffin
- Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, VIC, Australia
| | - Georg Ramm
- Clive and Vera Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Borries Demeler
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada.,Department of Chemistry, University of Montana, Missoula, MT, USA
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand. .,Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, VIC, Australia.
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Vigouroux A, Meyer T, Naretto A, Legrand P, Aumont-Nicaise M, Di Cicco A, Renoud S, Doré J, Lévy D, Vial L, Lavire C, Moréra S. Characterization of the first tetrameric transcription factor of the GntR superfamily with allosteric regulation from the bacterial pathogen Agrobacterium fabrum. Nucleic Acids Res 2021; 49:529-546. [PMID: 33313837 PMCID: PMC7797058 DOI: 10.1093/nar/gkaa1181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/12/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
A species-specific region, denoted SpG8-1b allowing hydroxycinnamic acids (HCAs) degradation is important for the transition between the two lifestyles (rhizospheric versus pathogenic) of the plant pathogen Agrobacterium fabrum. Indeed, HCAs can be either used as trophic resources and/or as induced-virulence molecules. The SpG8-1b region is regulated by two transcriptional regulators, namely, HcaR (Atu1422) and Atu1419. In contrast to HcaR, Atu1419 remains so far uncharacterized. The high-resolution crystal structures of two fortuitous citrate complexes, two DNA complexes and the apoform revealed that the tetrameric Atu1419 transcriptional regulator belongs to the VanR group of Pfam PF07729 subfamily of the large GntR superfamily. Until now, GntR regulators were described as dimers. Here, we showed that Atu1419 represses three genes of the HCAs catabolic pathway. We characterized both the effector and DNA binding sites and identified key nucleotides in the target palindrome. From promoter activity measurement using defective gene mutants, structural analysis and gel-shift assays, we propose N5,N10-methylenetetrahydrofolate as the effector molecule, which is not a direct product/substrate of the HCA degradation pathway. The Zn2+ ion present in the effector domain has both a structural and regulatory role. Overall, our work shed light on the allosteric mechanism of transcription employed by this GntR repressor.
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Affiliation(s)
- Armelle Vigouroux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Thibault Meyer
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Anaïs Naretto
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France
| | - Magali Aumont-Nicaise
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Aurélie Di Cicco
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Sébastien Renoud
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Jeanne Doré
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Daniel Lévy
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Ludovic Vial
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Céline Lavire
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Solange Moréra
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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Molecular Cloning, Purification and Characterization of Mce1R of Mycobacterium tuberculosis. Mol Biotechnol 2021; 63:200-220. [PMID: 33423211 DOI: 10.1007/s12033-020-00293-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2020] [Indexed: 10/22/2022]
Abstract
The mce1 operon of Mycobacterium tuberculosis, important for lipid metabolism/transport, host cell invasion, modulation of host immune response and pathogenicity, is under the transcriptional control of Mce1R. Hence characterizing Mce1R is an important step for novel anti-tuberculosis drug discovery. The present study reports functional and in silico characterization of Mce1R. In this work, we have computationally modeled the structure of Mce1R and have validated the structure by computational and experimental methods. Mce1R has been shown to harbor the canonical VanR-like structure with a flexible N-terminal 'arm', carrying conserved positively charged residues, most likely involved in the operator DNA binding. The mce1R gene has been cloned, expressed, purified and its DNA-binding activity has been measured in vitro. The Kd value for Mce1R-operator DNA interaction has been determined to be 0.35 ± 0.02 µM which implies that Mce1R binds to DNA with moderate affinity compared to the other FCD family of regulators. So far, this is the first report for measuring the DNA-binding affinity of any VanR-type protein. Despite significant sequence similarity at the N-terminal domain, the wHTH motif of Mce1R exhibits poor conservancy of amino acid residues, critical for DNA-binding, thus results in moderate DNA-binding affinity. The N-terminal DNA-binding domain is structurally dynamic while the C-terminal domain showed significant stability and such profile of structural dynamics is most likely to be preserved in the structural orthologs of Mce1R. In addition to this, a cavity has been detected in the C-terminal domain of Mce1R which contains a few conserved residues. Comparison with other FCD family of regulators suggests that most of the conserved residues might be critical for binding to specific ligand. The max pKd value and drug score for the cavity are estimated to be 9.04 and 109 respectively suggesting that the cavity represents a suitable target site for novel anti-tuberculosis drug discovery approaches.
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Key Enzymes for Anaerobic Lactate Metabolism in Geobacter sulfurreducens. Appl Environ Microbiol 2021; 87:AEM.01968-20. [PMID: 33158892 DOI: 10.1128/aem.01968-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/22/2020] [Indexed: 11/20/2022] Open
Abstract
Growth of Geobacter sulfurreducens PCA on lactate was enhanced by laboratory adaptive evolution. The enhanced growth was considered to be attributed to increased expression of the sucCD genes, encoding a succinyl-coenzyme A (CoA) synthetase. To further investigate the function of the succinyl-CoA synthetase, the sucCD genes were deleted from G. sulfurreducens The mutant showed defective growth on lactate but not on acetate. Introduction of the sucCD genes into the mutant restored the full potential to grow on lactate. These results verify the importance of the succinyl-CoA synthetase in growth on lactate. Genome analysis of Geobacter species identified candidate genes, GSU1623, GSU1624, and GSU1620, for lactate dehydrogenase. Deletion mutants of the identified genes for d-lactate dehydrogenase (ΔGSU1623 ΔGSU1624 mutant) or l-lactate dehydrogenase (ΔGSU1620 mutant) could not grow on d-lactate or l-lactate but could grow on acetate and l- or d-lactate, respectively. Introduction of the respective genes into the mutants allowed growth on the corresponding lactate stereoisomer. These results suggest that the identified genes were essential for d- or l-lactate utilization. The lacZ reporter assay demonstrated that the putative promoter regions were more active during growth on lactate than during growth on acetate, indicating that the genes for the lactate dehydrogenases were expressed more during growth on lactate than during growth on acetate. The gene deletion phenotypes and the expression profiles indicate that there are metabolic switches between lactate and acetate. This study advances the understanding of anaerobic lactate utilization in G. sulfurreducens IMPORTANCE Lactate is a microbial fermentation product as well as a source of carbon and electrons for microorganisms in the environment. Furthermore, lactate is a common amendment for stimulation of microbial growth in environmental biotechnology applications. However, anaerobic metabolism of lactate has been poorly studied for environmentally relevant microorganisms. Geobacter species are found in various environments and environmental biotechnology applications. By employing genomic and genetic approaches, succinyl-CoA synthetase and lactate dehydrogenase were identified as key enzymes in anaerobic metabolism of lactate in Geobacter sulfurreducens, a representative Geobacter species. Differential gene expression during growth on lactate and acetate was observed, demonstrating that G. sulfurreducens could metabolically switch to adapt to available substrates in the environment. The findings provide new insights into basic physiology in lactate metabolism as well as cellular responses to growth conditions in the environment and can be informative for the application of lactate in environmental biotechnology.
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Nouwen N, Arrighi JF, Gully D, Giraud E. RibBX of Bradyrhizobium ORS285 Plays an Important Role in Intracellular Persistence in Various Aeschynomene Host Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:88-99. [PMID: 33226302 DOI: 10.1094/mpmi-07-20-0209-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bradyrhizobium ORS285 forms a nitrogen-fixating symbiosis with both Nod factor (NF)-dependent and NF-independent Aeschynomene spp. The Bradyrhizobium ORS285 ribBA gene encodes for a putative bifunctional enzyme with 3,4-dihydroxybutanone phosphate (3,4-DHBP) synthase and guanosine triphosphate (GTP) cyclohydrolase II activities, catalyzing the initial steps in the riboflavin biosynthesis pathway. In this study, we show that inactivating the ribBA gene does not cause riboflavin auxotrophy under free-living conditions and that, as shown for RibBAs from other bacteria, the GTP cyclohydrolase II domain has no enzymatic activity. For this reason, we have renamed the annotated ribBA as ribBX. Because we were unable to identify other ribBA or ribA and ribB homologs in the genome of Bradyrhizobium ORS285, we hypothesize that the ORS285 strain can use unconventional enzymes or an alternative pathway for the initial steps of riboflavin biosynthesis. Inactivating ribBX has a drastic impact on the interaction of Bradyrhizobium ORS285 with many of the tested Aeschynomene spp. In these Aeschynomene spp., the ORS285 ribBX mutant is able to infect the plant host cells but the intracellular infection is not maintained and the nodules senesce early. This phenotype can be complemented by reintroduction of the 3,4-DHBP synthase domain alone. Our results indicate that, in Bradyrhizobium ORS285, the RibBX protein is not essential for riboflavin biosynthesis under free-living conditions and we hypothesize that its activity is needed to sustain riboflavin biosynthesis under certain symbiotic conditions.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Jean-Francois Arrighi
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Djamel Gully
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
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46
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Lin Z, Sun Y, Liu Y, Tong S, Shang Z, Cai Y, Lin W. Structural and Functional Analyses of the Transcription Repressor DgoR From Escherichia coli Reveal a Divalent Metal-Containing D-Galactonate Binding Pocket. Front Microbiol 2020; 11:590330. [PMID: 33224125 PMCID: PMC7674646 DOI: 10.3389/fmicb.2020.590330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/20/2020] [Indexed: 11/21/2022] Open
Abstract
The transcription repressor of D-galactonate metabolism, DgoR, from Escherichia coli belongs to the FadR family of the GntR superfamily. In the presence of D-galactonate, DgoR binds to two inverted repeats overlapping the dgo cis-acting promoter repressing the expression of genes involved in D-galactonate metabolism. To further understand the structural and molecular details of ligand and effector interactions between D-galactonate and this FadR family member, herein we solved the crystal structure of C-terminal domain of DgoR (DgoR_C), which revealed a unique divalent metal-containing substrate binding pocket. The metal ion is required for D-galactonate binding, as evidenced by the dramatically decreased affinity between D-galactonate and DgoR in the presence of EDTA, which can be reverted by the addition of Zn2+, Mg2+, and Ca2+. The key amino acid residues involved in the interactions between D-galactonate and DgoR were revealed by molecular docking studies and further validated with biochemical studies by site-directed mutagenesis. It was found that changes to alanine in residues R102, W181, T191, and R224 resulted in significantly decreased binding affinities for D-galactonate, as determined by EMSA and MST assays. These results suggest that the molecular modifications induced by a D-galactonate and a metal binding in the DgoR are required for DNA binding activity and consequently, transcriptional inhibition.
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Affiliation(s)
- Zhaozhu Lin
- Department of Microbiology and Immunology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yi Sun
- Department of Microbiology and Immunology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yu Liu
- Department of Chemistry, Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, United States
| | - Shujuan Tong
- Department of Microbiology and Immunology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Zhuo Shang
- Department of Microbiology and Immunology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yuanheng Cai
- Biochemistry and Cell Biology Department, Stony Brook University, Stony Brook, NY, United States
| | - Wei Lin
- Department of Microbiology and Immunology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China.,Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing, China
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47
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Whole Genome Sequencing and Tn 5-Insertion Mutagenesis of Pseudomonas taiwanensis CMS to Probe Its Antagonistic Activity Against Rice Bacterial Blight Disease. Int J Mol Sci 2020; 21:ijms21228639. [PMID: 33207795 PMCID: PMC7696974 DOI: 10.3390/ijms21228639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 01/07/2023] Open
Abstract
The Gram-negative bacterium Pseudomonas taiwanensis is a novel bacterium that uses shrimp shell waste as its sole sources of carbon and nitrogen. It is a versatile bacterium with potential for use in biological control, with activities including toxicity toward insects, fungi, and the rice pathogen Xanthomonas oryzae pv.oryzae (Xoo). In this study, the complete 5.08-Mb genome sequence of P. taiwanensis CMS was determined by a combination of NGS/Sanger sequencing and optical mapping. Comparison of optical maps of seven Pseudomonas species showed that P. taiwanensis is most closely related to P. putida KT 2400. We screened a total of 11,646 individual Tn5-transponson tagged strains to identify genes that are involved in the production and regulation of the iron-chelator pyoverdine in P. taiwanensis, which is a key anti-Xoo factor. Our results indicated that the two-component system (TCS) EnvZ/OmpR plays a positive regulatory role in the production of pyoverdine, whereas the sigma factor RpoS functions as a repressor. The knowledge of the molecular basis of the regulation of pyoverdine by P. taiwanensis provided herein will be useful for its development for use in biological control, including as an anti-Xoo agent.
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Arya G, Pal M, Sharma M, Singh B, Singh S, Agrawal V, Chaba R. Molecular insights into effector binding by DgoR, a GntR/FadR family transcriptional repressor of D-galactonate metabolism in Escherichia coli. Mol Microbiol 2020; 115:591-609. [PMID: 33068046 DOI: 10.1111/mmi.14625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 01/23/2023]
Abstract
Several GntR/FadR transcriptional regulators govern sugar acid metabolism in bacteria. Although effectors have been identified for a few sugar acid regulators, the mode of effector binding is unknown. Even in the overall FadR subfamily, there are limited details on effector-regulator interactions. Here, we identified the effector-binding cavity in Escherichia coli DgoR, a FadR subfamily transcriptional repressor of D-galactonate metabolism that employs D-galactonate as its effector. Using a genetic screen, we isolated several dgoR superrepressor alleles. Blind docking suggested eight amino acids corresponding to these alleles to form a part of the effector-binding cavity. In vivo and in vitro assays showed that these mutations compromise the inducibility of DgoR without affecting its oligomeric status or affinity for target DNA. Taking Bacillus subtilis GntR as a representative, we demonstrated that the effector-binding cavity is similar among FadR subfamily sugar acid regulators. Finally, a comparison of sugar acid regulators with other FadR members suggested conserved features of effector-regulator recognition within the FadR subfamily. Sugar acid metabolism is widely implicated in bacterial colonization and virulence. The present study sets the basis to investigate the influence of natural genetic variations in FadR subfamily regulators on their sensitivity to sugar acids and ultimately on host-bacterial interactions.
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Affiliation(s)
- Garima Arya
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Mohinder Pal
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Monika Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, India
| | - Bhupinder Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Swati Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Vishal Agrawal
- Department of Biochemistry, Panjab University, Chandigarh, India
| | - Rachna Chaba
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
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Graf von Armansperg B, Koller F, Gericke N, Hellwig M, Jagtap PKA, Heermann R, Hennig J, Henle T, Lassak J. Transcriptional regulation of the N ε -fructoselysine metabolism in Escherichia coli by global and substrate-specific cues. Mol Microbiol 2020; 115:175-190. [PMID: 32979851 DOI: 10.1111/mmi.14608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 12/19/2022]
Abstract
Thermally processed food is an important part of the human diet. Heat-treatment, however, promotes the formation of so-called Amadori rearrangement products, such as fructoselysine. The gut microbiota including Escherichia coli can utilize these compounds as a nutrient source. While the degradation route for fructoselysine is well described, regulation of the corresponding pathway genes frlABCD remained poorly understood. Here, we used bioinformatics combined with molecular and biochemical analyses and show that fructoselysine metabolism in E. coli is tightly controlled at the transcriptional level. The global regulator CRP (CAP) as well as the alternative sigma factor σ32 (RpoH) contribute to promoter activation at high cAMP-levels and inside warm-blooded hosts, respectively. In addition, we identified and characterized a transcriptional regulator FrlR, encoded adjacent to frlABCD, as fructoselysine-6-phosphate specific repressor. Our study provides profound evidence that the interplay of global and substrate-specific regulation is a perfect adaptation strategy to efficiently utilize unusual substrates within the human gut environment.
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Affiliation(s)
| | - Franziska Koller
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nicola Gericke
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Hellwig
- Chair of Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | | | - Ralf Heermann
- Institute of Molecular Physiology, Microbiology and Wine Research, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Thomas Henle
- Chair of Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Jürgen Lassak
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Munich, Germany
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50
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Dudek M, Dieudonné A, Jouanneau D, Rochat T, Michel G, Sarels B, Thomas F. Regulation of alginate catabolism involves a GntR family repressor in the marine flavobacterium Zobellia galactanivorans DsijT. Nucleic Acids Res 2020; 48:7786-7800. [PMID: 32585009 PMCID: PMC7641319 DOI: 10.1093/nar/gkaa533] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/02/2020] [Accepted: 06/10/2020] [Indexed: 12/19/2022] Open
Abstract
Marine flavobacteria possess dedicated Polysaccharide Utilization Loci (PULs) enabling efficient degradation of a variety of algal polysaccharides. The expression of these PULs is tightly controlled by the presence of the substrate, yet details on the regulatory mechanisms are still lacking. The marine flavobacterium Zobellia galactanivorans DsijT digests many algal polysaccharides, including alginate from brown algae. Its complex Alginate Utilization System (AUS) comprises a PUL and several other loci. Here, we showed that the expression of the AUS is strongly and rapidly (<30 min) induced upon addition of alginate, leading to biphasic substrate utilization. Polymeric alginate is first degraded into smaller oligosaccharides that accumulate in the extracellular medium before being assimilated. We found that AusR, a GntR family protein encoded within the PUL, regulates alginate catabolism by repressing the transcription of most AUS genes. Based on our genetic, genomic, transcriptomic and biochemical results, we propose the first model of regulation for a PUL in marine bacteria. AusR binds to promoters of AUS genes via single, double or triple copies of operator. Upon addition of alginate, secreted enzymes expressed at a basal level catalyze the initial breakdown of the polymer. Metabolic intermediates produced during degradation act as effectors of AusR and inhibit the formation of AusR/DNA complexes, thus lifting transcriptional repression.
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Affiliation(s)
- Magda Dudek
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Anissa Dieudonné
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Diane Jouanneau
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Tatiana Rochat
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Gurvan Michel
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Benoit Sarels
- Sorbonne Université, CNRS, Laboratoire Jacques-Louis Lions, Université de Paris, 75252 Paris, France
| | - François Thomas
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
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