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Xin R, Zhang K, Yu D, Zhang Y, Ma Y, Niu Z. Cyanobacterial extracellular antibacterial substances could promote the spread of antibiotic resistance: impacts and reasons. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:2139-2147. [PMID: 37947439 DOI: 10.1039/d3em00306j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Many studies have shown that antibiotic resistance genes (ARGs) can be facilitated by a variety of antibacterial substances. Cyanobacteria are photosynthetic bacteria that are widely distributed in the ocean. Some extracellular substances produced by marine cyanobacteria have been found to possess antibacterial activity. However, the impact of these extracellular substances on ARGs is unclear. Therefore, we established groups of seawater microcosms that contained different concentrations (1000, 100, 10, 1, 0.1, 0.01, and 0 μg mL-1) of cyanobacterial extracellular substances (CES), and tracked the changes of 17 types of ARGs, the integron gene (intI1), as well as the bacterial community at different time points. The results showed that CES could enrich most ARGs (15/17) in the initial stage, particularly at low concentrations (10 and 100 μg mL-1). The correlation analysis showed a positive correlation between several ARGs and intI1. It is suggested that the abundance of intI1 increased with CES may contribute to the changes of these ARGs, and co-resistance of CES may be the underlying reason for the similar variation pattern of some ARGs. Moreover, the results of qPCR and high-throughput sequencing of 16S rRNA showed that CES had an inhibitory impact on the growth of bacterial communities. High concentrations of CES were found to alter the structure of bacterial communities. Co-occurrence networks showed that bacteria elevated in the high concentration group of CES and might serve as the potential hosts for a variety of ARGs. In general, marine cyanobacteria could play an important role in the global dissemination of ARGs and antibiotic-resistant bacteria (ARBs).
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Affiliation(s)
- Rui Xin
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, China.
| | - Kai Zhang
- Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, School of Geographic Sciences, Xinyang Normal University, Xinyang 464000, China
| | - Dongjin Yu
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, China.
| | - Ying Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yongzheng Ma
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, China.
| | - Zhiguang Niu
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, China.
- The International Joint Institute of Tianjin University, Fuzhou 350207, China
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Fontana A, Falasconi I, Bellassi P, Fanfoni E, Puglisi E, Morelli L. Comparative Genomics of Halobacterium salinarum Strains Isolated from Salted Foods Reveals Protechnological Genes for Food Applications. Microorganisms 2023; 11:microorganisms11030587. [PMID: 36985161 PMCID: PMC10058572 DOI: 10.3390/microorganisms11030587] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/15/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Archaeal cell factories are becoming of great interest given their ability to produce a broad range of value-added compounds. Moreover, the Archaea domain often includes extremophilic microorganisms, facilitating their cultivation at the industrial level under nonsterile conditions. Halophilic archaea are studied for their ability to grow in environments with high NaCl concentrations. In this study, nine strains of Halobacterium salinarum were isolated from three different types of salted food, sausage casings, salted codfish, and bacon, and their genomes were sequenced along with the genome of the collection strain CECT 395. A comparative genomic analysis was performed on these newly sequenced genomes and the publicly available ones for a total of 19 H. salinarum strains. We elucidated the presence of unique gene clusters of the species in relation to the different ecological niches of isolation (salted foods, animal hides, and solar saltern sediments). Moreover, genome mining at the single-strain level highlighted the metabolic potential of H. salinarum UC4242, which revealed the presence of different protechnological genes (vitamins and myo-inositol biosynthetic pathways, aroma- and texture-related features, and antimicrobial compounds). Despite the presence of genes of potential concern (e.g., those involved in biogenic amine production), all the food isolates presented archaeocin-related genes (halocin-C8 and sactipeptides).
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Affiliation(s)
- Alessandra Fontana
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Bissolati, 74, 26100 Cremona, Italy
- Correspondence: (A.F.); (L.M.)
| | - Irene Falasconi
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Bissolati, 74, 26100 Cremona, Italy
| | - Paolo Bellassi
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Bissolati, 74, 26100 Cremona, Italy
| | - Elisabetta Fanfoni
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Bissolati, 74, 26100 Cremona, Italy
| | - Edoardo Puglisi
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Emilia Parmense, 84, 29122 Piacenza, Italy
| | - Lorenzo Morelli
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Bissolati, 74, 26100 Cremona, Italy
- Department for Sustainable Food Process—DiSTAS, Università Cattolica del Sacro Cuore, Via Emilia Parmense, 84, 29122 Piacenza, Italy
- Correspondence: (A.F.); (L.M.)
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A Hyperthermoactive-Cas9 Editing Tool Reveals the Role of a Unique Arsenite Methyltransferase in the Arsenic Resistance System of Thermus thermophilus HB27. mBio 2021; 12:e0281321. [PMID: 34872358 PMCID: PMC8649762 DOI: 10.1128/mbio.02813-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Arsenic detoxification systems can be found in a wide range of organisms, from bacteria to humans. In a previous study, we discovered an arsenic-responsive transcriptional regulator in the thermophilic bacterium Thermus thermophilus HB27 (TtSmtB). Here, we characterize the arsenic resistance system of T. thermophilus in more detail. We employed TtSmtB-based pulldown assays with protein extracts from cultures treated with arsenate and arsenite to obtain an S-adenosyl-l-methionine (SAM)-dependent arsenite methyltransferase (TtArsM). In vivo and in vitro analyses were performed to shed light on this new component of the arsenic resistance network and its peculiar catalytic mechanism. Heterologous expression of TtarsM in Escherichia coli resulted in arsenite detoxification at mesophilic temperatures. Although TtArsM does not contain a canonical arsenite binding site, the purified protein does catalyze SAM-dependent arsenite methylation with formation of monomethylarsenites (MMAs) and dimethylarsenites (DMAs). In addition, in vitro analyses confirmed the unique interaction between TtArsM and TtSmtB. Next, a highly efficient ThermoCas9-based genome-editing tool was developed to delete the TtArsM-encoding gene on the T. thermophilus genome and to confirm its involvement in the arsenite detoxification system. Finally, the TtarsX efflux pump gene in the T. thermophilus ΔTtarsM genome was substituted by a gene encoding a stabilized yellow fluorescent protein (sYFP) to create a sensitive genome-based bioreporter system for the detection of arsenic ions.
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MdaB and NfrA, two novel reductases important in the survival and persistence of the major enteropathogen Campylobacter jejuni. J Bacteriol 2021; 204:e0042121. [PMID: 34606373 PMCID: PMC8765430 DOI: 10.1128/jb.00421-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The paralogues RrpA and RrpB, which are members of the MarR family of DNA binding proteins, are important for the survival of the global bacterial foodborne pathogen Campylobacter jejuni under redox stress. We report that RrpA is a positive regulator of mdaB, encoding a flavin-dependent quinone reductase that contributes to the protection from redox stress mediated by structurally diverse quinones, while RrpB negatively regulates the expression of cj1555c (renamed nfrA for NADPH-flavin reductase A), encoding a flavin reductase. NfrA reduces riboflavin at a greater rate than its derivatives, suggesting that exogenous free flavins are the natural substrate. MdaB and NfrA both prefer NADPH as an electron donor. Cysteine substitution and posttranslational modification analyses indicated that RrpA and RrpB employ a cysteine-based redox switch. Complete genome sequence analyses revealed that mdaB is frequently found in Campylobacter and related Helicobacter spp., while nfrA is predominant in C. jejuni strains. Quinones and flavins are redox cycling agents secreted by a wide range of cell types that can form damaging superoxide by one-electron reactions. We propose a model for stress adaptation where MdaB and NfrA facilitate a two-electron reduction mechanism to the less toxic hydroquinones, thus aiding survival and persistence of this major pathogen. IMPORTANCE Changes in cellular redox potential result in alteration in the oxidation state of intracellular metabolites and enzymes; consequently, cells make adjustments that favor growth and survival. The work we present here answers some of the many questions that have remained elusive over the years of investigation into the enigmatic microaerophile bacterium Campylobacter jejuni. We employed molecular approaches to understand the regulation mechanisms and functional analyses to reveal the roles of two novel quinone and flavin reductases; both serve as major pools of cellular redox-active molecules. This work extends our knowledge on bacterial redox sensing mechanisms and the significance of hemostasis.
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Lewis AM, Recalde A, Bräsen C, Counts JA, Nussbaum P, Bost J, Schocke L, Shen L, Willard DJ, Quax TEF, Peeters E, Siebers B, Albers SV, Kelly RM. The biology of thermoacidophilic archaea from the order Sulfolobales. FEMS Microbiol Rev 2021; 45:fuaa063. [PMID: 33476388 PMCID: PMC8557808 DOI: 10.1093/femsre/fuaa063] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/26/2020] [Indexed: 12/13/2022] Open
Abstract
Thermoacidophilic archaea belonging to the order Sulfolobales thrive in extreme biotopes, such as sulfuric hot springs and ore deposits. These microorganisms have been model systems for understanding life in extreme environments, as well as for probing the evolution of both molecular genetic processes and central metabolic pathways. Thermoacidophiles, such as the Sulfolobales, use typical microbial responses to persist in hot acid (e.g. motility, stress response, biofilm formation), albeit with some unusual twists. They also exhibit unique physiological features, including iron and sulfur chemolithoautotrophy, that differentiate them from much of the microbial world. Although first discovered >50 years ago, it was not until recently that genome sequence data and facile genetic tools have been developed for species in the Sulfolobales. These advances have not only opened up ways to further probe novel features of these microbes but also paved the way for their potential biotechnological applications. Discussed here are the nuances of the thermoacidophilic lifestyle of the Sulfolobales, including their evolutionary placement, cell biology, survival strategies, genetic tools, metabolic processes and physiological attributes together with how these characteristics make thermoacidophiles ideal platforms for specialized industrial processes.
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Affiliation(s)
- April M Lewis
- Department of Chemical and Biomolecular Engineering, North Carolina State University. Raleigh, NC 27695, USA
| | - Alejandra Recalde
- Institute for Biology, Molecular Biology of Archaea, University of Freiburg, 79104 Freiburg, Germany
| | - Christopher Bräsen
- Department of Molecular Enzyme Technology and Biochemistry, Environmental Microbiology and Biotechnology, and Centre for Water and Environmental Research, University of Duisburg-Essen, 45117 Essen, Germany
| | - James A Counts
- Department of Chemical and Biomolecular Engineering, North Carolina State University. Raleigh, NC 27695, USA
| | - Phillip Nussbaum
- Institute for Biology, Molecular Biology of Archaea, University of Freiburg, 79104 Freiburg, Germany
| | - Jan Bost
- Institute for Biology, Molecular Biology of Archaea, University of Freiburg, 79104 Freiburg, Germany
| | - Larissa Schocke
- Department of Molecular Enzyme Technology and Biochemistry, Environmental Microbiology and Biotechnology, and Centre for Water and Environmental Research, University of Duisburg-Essen, 45117 Essen, Germany
| | - Lu Shen
- Department of Molecular Enzyme Technology and Biochemistry, Environmental Microbiology and Biotechnology, and Centre for Water and Environmental Research, University of Duisburg-Essen, 45117 Essen, Germany
| | - Daniel J Willard
- Department of Chemical and Biomolecular Engineering, North Carolina State University. Raleigh, NC 27695, USA
| | - Tessa E F Quax
- Archaeal Virus–Host Interactions, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Eveline Peeters
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Bettina Siebers
- Department of Molecular Enzyme Technology and Biochemistry, Environmental Microbiology and Biotechnology, and Centre for Water and Environmental Research, University of Duisburg-Essen, 45117 Essen, Germany
| | - Sonja-Verena Albers
- Institute for Biology, Molecular Biology of Archaea, University of Freiburg, 79104 Freiburg, Germany
| | - Robert M Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University. Raleigh, NC 27695, USA
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Gallo G, Puopolo R, Carbonaro M, Maresca E, Fiorentino G. Extremophiles, a Nifty Tool to Face Environmental Pollution: From Exploitation of Metabolism to Genome Engineering. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:5228. [PMID: 34069056 PMCID: PMC8157027 DOI: 10.3390/ijerph18105228] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/06/2021] [Accepted: 05/09/2021] [Indexed: 12/13/2022]
Abstract
Extremophiles are microorganisms that populate habitats considered inhospitable from an anthropocentric point of view and are able to tolerate harsh conditions such as high temperatures, extreme pHs, high concentrations of salts, toxic organic substances, and/or heavy metals. These microorganisms have been broadly studied in the last 30 years and represent precious sources of biomolecules and bioprocesses for many biotechnological applications; in this context, scientific efforts have been focused on the employment of extremophilic microbes and their metabolic pathways to develop biomonitoring and bioremediation strategies to face environmental pollution, as well as to improve biorefineries for the conversion of biomasses into various chemical compounds. This review gives an overview on the peculiar metabolic features of certain extremophilic microorganisms, with a main focus on thermophiles, which make them attractive for biotechnological applications in the field of environmental remediation; moreover, it sheds light on updated genetic systems (also those based on the CRISPR-Cas tool), which expand the potentialities of these microorganisms to be genetically manipulated for various biotechnological purposes.
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Affiliation(s)
- Giovanni Gallo
- Department of Biology, University of Naples Federico II, Via Cinthia 21, 80126 Napoli, Italy; (G.G.); (R.P.); (M.C.); (E.M.)
- Consiglio Nazionale delle Ricerche CNR, Institute of Polymers, Composites and Biomaterials (IPCB), Via Campi Flegrei, 34, 80078 Pozzuoli, Italy
| | - Rosanna Puopolo
- Department of Biology, University of Naples Federico II, Via Cinthia 21, 80126 Napoli, Italy; (G.G.); (R.P.); (M.C.); (E.M.)
| | - Miriam Carbonaro
- Department of Biology, University of Naples Federico II, Via Cinthia 21, 80126 Napoli, Italy; (G.G.); (R.P.); (M.C.); (E.M.)
| | - Emanuela Maresca
- Department of Biology, University of Naples Federico II, Via Cinthia 21, 80126 Napoli, Italy; (G.G.); (R.P.); (M.C.); (E.M.)
| | - Gabriella Fiorentino
- Department of Biology, University of Naples Federico II, Via Cinthia 21, 80126 Napoli, Italy; (G.G.); (R.P.); (M.C.); (E.M.)
- Consiglio Nazionale delle Ricerche CNR, Institute of Polymers, Composites and Biomaterials (IPCB), Via Campi Flegrei, 34, 80078 Pozzuoli, Italy
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Aulitto M, Gallo G, Puopolo R, Mormone A, Limauro D, Contursi P, Piochi M, Bartolucci S, Fiorentino G. Genomic Insight of Alicyclobacillus mali FL18 Isolated From an Arsenic-Rich Hot Spring. Front Microbiol 2021; 12:639697. [PMID: 33897644 PMCID: PMC8060452 DOI: 10.3389/fmicb.2021.639697] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/05/2021] [Indexed: 12/24/2022] Open
Abstract
Extreme environments are excellent places to find microorganisms capable of tolerating extreme temperature, pH, salinity pressure, and elevated concentration of heavy metals and other toxic compounds. In the last decades, extremophilic microorganisms have been extensively studied since they can be applied in several fields of biotechnology along with their enzymes. In this context, the characterization of heavy metal resistance determinants in thermophilic microorganisms is the starting point for the development of new biosystems and bioprocesses for environmental monitoring and remediation. This work focuses on the isolation and the genomic exploration of a new arsenic-tolerant microorganism, classified as Alicyclobacillus mali FL18. The bacterium was isolated from a hot mud pool of the solfataric terrains in Pisciarelli, a well-known hydrothermally active zone of the Campi Flegrei volcano near Naples in Italy. A. mali FL18 showed a good tolerance to arsenite (MIC value of 41 mM), as well as to other metals such as nickel (MIC 30 mM), cobalt, and mercury (MIC 3 mM and 17 μM, respectively). Signatures of arsenic resistance genes (one arsenate reductase, one arsenite methyltransferase, and several arsenite exporters) were found interspersed in the genome as well as several multidrug resistance efflux transporters that could be involved in the export of drugs and heavy metal ions. Moreover, the strain showed a high resistance to bacitracin and ciprofloxacin, suggesting that the extreme environment has positively selected multiple resistances to different toxic compounds. This work provides, for the first time, insights into the heavy metal tolerance and antibiotic susceptibility of an Alicyclobacillus strain and highlights its putative molecular determinants.
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Affiliation(s)
- Martina Aulitto
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Giovanni Gallo
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
- Institute of Polymers, Composites and Biomaterials (IPCB), Consiglio Nazionale delle Ricerche CNR, Pozzuoli, Italy
| | - Rosanna Puopolo
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Angela Mormone
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli Osservatorio Vesuviano, Naples, Italy
| | - Danila Limauro
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Patrizia Contursi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Monica Piochi
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli Osservatorio Vesuviano, Naples, Italy
| | - Simonetta Bartolucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Gabriella Fiorentino
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Naples, Italy
- Institute of Polymers, Composites and Biomaterials (IPCB), Consiglio Nazionale delle Ricerche CNR, Pozzuoli, Italy
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Puopolo R, Sorrentino I, Gallo G, Piscitelli A, Giardina P, Le Goff A, Fiorentino G. Self-assembling thermostable chimeras as new platform for arsenic biosensing. Sci Rep 2021; 11:2991. [PMID: 33542380 PMCID: PMC7862302 DOI: 10.1038/s41598-021-82648-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/21/2021] [Indexed: 01/30/2023] Open
Abstract
The correct immobilization and orientation of enzymes on nanosurfaces is a crucial step either for the realization of biosensors, as well as to guarantee the efficacy of the developed biomaterials. In this work we produced two versions of a chimeric protein, namely ArsC-Vmh2 and Vmh2-ArsC, which combined the self-assembling properties of Vmh2, a hydrophobin from Pleurotus ostreatus, with that of TtArsC, a thermophilic arsenate reductase from Thermus thermophilus; both chimeras were heterologously expressed in Escherichia coli and purified from inclusion bodies. They were characterized for their enzymatic capability to reduce As(V) into As(III), as well as for their immobilization properties on polystyrene and gold in comparison to the native TtArsC. The chimeric proteins immobilized on polystyrene can be reused up to three times and stored for 15 days with 50% of activity loss. Immobilization on gold electrodes showed that both chimeras follow a classic Langmuir isotherm model towards As(III) recognition, with an association constant (KAsIII) between As(III) and the immobilized enzyme, equal to 650 (± 100) L mol-1 for ArsC-Vmh2 and to 1200 (± 300) L mol-1 for Vmh2-ArsC. The results demonstrate that gold-immobilized ArsC-Vmh2 and Vmh2-ArsC can be exploited as electrochemical biosensors to detect As(III).
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Affiliation(s)
- Rosanna Puopolo
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Ilaria Sorrentino
- Department of Molecular Chemistry, CNRS, University Grenoble Alpes, 38000, Grenoble, France
| | - Giovanni Gallo
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Alessandra Piscitelli
- Department of Chemical Sciences, University of Naples Federico II, 80126, Naples, Italy
| | - Paola Giardina
- Department of Chemical Sciences, University of Naples Federico II, 80126, Naples, Italy
| | - Alan Le Goff
- Department of Molecular Chemistry, CNRS, University Grenoble Alpes, 38000, Grenoble, France.
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Wang Z, Wang T, Cui R, Zhang Z, Chen K, Li M, Hua Y, Gu H, Xu L, Wang Y, Yang Y, Shen X. HpaR, the Repressor of Aromatic Compound Metabolism, Positively Regulates the Expression of T6SS4 to Resist Oxidative Stress in Yersinia pseudotuberculosis. Front Microbiol 2020; 11:705. [PMID: 32362886 PMCID: PMC7180172 DOI: 10.3389/fmicb.2020.00705] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/26/2020] [Indexed: 12/25/2022] Open
Abstract
HpaR, a MarR family transcriptional regulator, was first identified in Escherichia coli W for its regulation of the hpa-meta operon. Little else is known regarding its functionality. Here, we report that in Yersinia pseudotuberculosis, HpaR negatively regulates the hpa-meta operon similar to in E. coli W. To investigate additional functions of HpaR, RNA sequencing was performed for both the wild-type and the ΔhpaR mutant, which revealed that the type VI secretion system (T6SS) was positively regulated by HpaR. T6SS4 is important for bacteria resisting environmental stress, especially oxidative stress. We demonstrate that HpaR facilitates bacteria resist oxidative stress by upregulating the expression of T6SS4 in Y. pseudotuberculosis. HpaR is also involved in biofilm formation, antibiotic resistance, adhesion to eukaryotic cells, and virulence in mice. These results greatly expand our knowledge of the functionality of HpaR and reveal a new pathway that regulates T6SS4.
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Affiliation(s)
- Zhuo Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Tietao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Rui Cui
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Zhenxing Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Keqi Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Mengyun Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yueyue Hua
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Huawei Gu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Lei Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Yantao Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, China
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Prathiviraj R, Chellapandi P. Modeling a global regulatory network of Methanothermobacter thermautotrophicus strain ∆H. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s13721-020-0223-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Sumi S, Suzuki Y, Matsuki T, Yamamoto T, Tsuruta Y, Mise K, Kawamura T, Ito Y, Shimada Y, Watanabe E, Watanabe S, Toriyabe M, Takano Shiratori H, Ueda K, Takano H. Light-inducible carotenoid production controlled by a MarR-type regulator in Corynebacterium glutamicum. Sci Rep 2019; 9:13136. [PMID: 31511549 PMCID: PMC6739363 DOI: 10.1038/s41598-019-49384-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/23/2019] [Indexed: 01/21/2023] Open
Abstract
Carotenoid production in some non-phototropic bacteria occurs in a light-dependent manner to protect cells from photo-oxidants. Knowledge regarding the transcriptional regulator involved in the light-dependent production of carotenoids of non-phototrophic bacteria has been mainly confined to coenzyme B12-based photo-sensitive regulator CarH/LitR family proteins belonging to a MerR family transcriptional regulator. In this study, we found that bacteria belonging to Micrococcales and Corynebacteriales exhibit light-dependent carotenoid-like pigment production including an amino acid-producer Corynebacterium glutamicum AJ1511. CrtR is a putative MarR family transcriptional regulator located in the divergent region of a carotenoid biosynthesis gene cluster in the genome of those bacteria. A null mutant for crtR of C. glutamicum AJ1511 exhibited constitutive production of carotenoids independent of light. A complemented strain of the crtR mutant produced carotenoids in a light-dependent manner. Transcriptional analysis revealed that the expression of carotenoid biosynthesis genes is regulated in a light-dependent manner in the wild type, while the transcription was upregulated in the crtR mutant irrespective of light. In vitro experiments demonstrated that a recombinant CrtR protein binds to the specific sequences within the intergenic region of crtR and crtE, which corresponds to −58 to −7 for crtE, and +26 to −28 for crtR with respect to the transcriptional start site, and serves as a repressor for crtE transcription directed by RNA polymerase containing SigA. Taken together, the results indicate that CrtR light-dependently controls the expression of the carotenoid gene cluster in C. glutamicum and probably closely related Actinobacteria.
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Affiliation(s)
- Satoru Sumi
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Yuto Suzuki
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Tetsuro Matsuki
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Takahiro Yamamoto
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Yudai Tsuruta
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Kou Mise
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Takuya Kawamura
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Yusuke Ito
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Yuka Shimada
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Erika Watanabe
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Shoko Watanabe
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Minami Toriyabe
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Hatsumi Takano Shiratori
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Kenji Ueda
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan
| | - Hideaki Takano
- Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, 252-0880, Japan.
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12
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Gallo G, Antonucci I, Pirone L, Amoresano A, Contursi P, Limauro D, Pedone E, Bartolucci S, Fiorentino G. A physicochemical investigation on the metal binding properties of TtSmtB, a thermophilic member of the ArsR/SmtB transcription factor family. Int J Biol Macromol 2019; 138:1056-1063. [PMID: 31356933 DOI: 10.1016/j.ijbiomac.2019.07.174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/12/2019] [Accepted: 07/25/2019] [Indexed: 01/06/2023]
Abstract
The transcription factors of the ArsR/SmtB family are widespread within the bacterial and archaeal kingdoms. They are transcriptional repressors able to sense a variety of metals and undergo allosteric conformational changes upon metal binding, resulting in derepression of genes involved in detoxification. So far, the molecular determinants of specificity, selectivity, and metal binding mechanism have been scarcely investigated in thermophilic microorganisms. TtSmtB, the only ArsR/SmtB member present in the genome of Thermus thermophilus HB27, was chosen as a model to shed light into such molecular mechanisms at high temperature. In the present study, using a multidisciplinary approach, a structural and functional characterization of the protein was performed focusing on its metal interaction and chemical-physical stability. Our data demonstrate that TtSmtB has two distinct metal binding sites per monomer and interacts with di-tri-penta-valent ions with different affinity. Detailed knowledge at molecular level of protein-metal interaction is remarkable to design metal binding domains as scaffolds in metal-based therapies as well as in metal biorecovery or biosensing in the environment.
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Affiliation(s)
- Giovanni Gallo
- Department of Biology, University of Naples Federico II, Napoli, Italy
| | | | - Luciano Pirone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples Federico II, Napoli, Italy
| | - Patrizia Contursi
- Department of Biology, University of Naples Federico II, Napoli, Italy
| | - Danila Limauro
- Department of Biology, University of Naples Federico II, Napoli, Italy
| | - Emilia Pedone
- Institute of Biostructure and Bioimaging, CNR, Napoli, Italy
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13
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Gu Q, Wu Q, Zhang J, Guo W, Ding Y, Wang J, Wu H, Sun M, Hou L, Wei X, Zhang Y. Isolation and Transcriptome Analysis of Phenol-Degrading Bacterium From Carbon-Sand Filters in a Full-Scale Drinking Water Treatment Plant. Front Microbiol 2018; 9:2162. [PMID: 30298058 PMCID: PMC6160575 DOI: 10.3389/fmicb.2018.02162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/23/2018] [Indexed: 02/03/2023] Open
Abstract
Phenol is a typical organic contaminant in the environment. To date, the biodegradation of phenol by microorganisms remains the preferred method for its removal and remediation, but data on phenol removal by drinking water biofilters are lacking. In this study, we used high-throughput sequencing to investigate the microbial community structure in a carbon-sand biofilter. The results indicated that the predominant bacterial group was Bacilli, followed by Gammaproteobacteria, Clostridia, and Alphaproteobacteria. In addition, a strain was capable of degrading phenol at low concentrations of 500 μg/L within 100 min was isolated and identified as Rhodococcus sp. CS-1. Transcriptome analysis results showed that Rhodococcus sp. CS-1 was able to degrade phenol via both the catechol and protocatechuate branch of the β-ketoadipate pathway. Furthermore, some novel candidate biomarkers (copper oxidase, copper chaperone, and MarR/DeoR/TetR family transcriptional regulators) were successfully identified to be potentially involved in phenol biodegradation. This study indicates that carbon-sand filters have the potential for remediation of phenol. The application of native microorganisms to drinking water treatment system is an adaptive strategy in oligotrophic water environments.
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Affiliation(s)
- Qihui Gu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Weipeng Guo
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Yu Ding
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Juan Wang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Huiqing Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Ming Sun
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Luanfeng Hou
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Xianhu Wei
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Youxiong Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
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14
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Goodman DA, Stedman KM. Comparative genetic and genomic analysis of the novel fusellovirus Sulfolobus spindle-shaped virus 10. Virus Evol 2018; 4:vey022. [PMID: 30094064 PMCID: PMC6080066 DOI: 10.1093/ve/vey022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Viruses that infect thermophilic Archaea are unique in both their structure and genetic makeup. The lemon-shaped fuselloviruses—which infect members of the order Sulfolobales, growing optimally at 80 °C and pH 3—are some of the most ubiquitous and best studied viruses of the thermoacidophilic Archaea. Nonetheless, much remains to be learned about these viruses. In order to investigate fusellovirus evolution, we have isolated and characterized a novel fusellovirus, Sulfolobus spindle-shaped virus 10 (formerly SSV-L1). Comparative genomic analyses highlight significant similarity with both SSV8 and SSV9, as well as conservation of promoter elements within the Fuselloviridae. SSV10 encodes five ORFs with no homology within or outside of the Fuselloviridae, as well as a putatively functional Cas4-like ORF, which may play a role in evading CRISPR-mediated host defenses. Moreover, we demonstrate the ability of SSV10 to withstand mutation in a fashion consistent with mutagenesis in SSV1.
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Affiliation(s)
- David A Goodman
- Biology Department, Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Kenneth M Stedman
- Biology Department, Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
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15
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Martinez-Pastor M, Tonner PD, Darnell CL, Schmid AK. Transcriptional Regulation in Archaea: From Individual Genes to Global Regulatory Networks. Annu Rev Genet 2018; 51:143-170. [PMID: 29178818 DOI: 10.1146/annurev-genet-120116-023413] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Archaea are major contributors to biogeochemical cycles, possess unique metabolic capabilities, and resist extreme stress. To regulate the expression of genes encoding these unique programs, archaeal cells use gene regulatory networks (GRNs) composed of transcription factor proteins and their target genes. Recent developments in genetics, genomics, and computational methods used with archaeal model organisms have enabled the mapping and prediction of global GRN structures. Experimental tests of these predictions have revealed the dynamical function of GRNs in response to environmental variation. Here, we review recent progress made in this area, from investigating the mechanisms of transcriptional regulation of individual genes to small-scale subnetworks and genome-wide global networks. At each level, archaeal GRNs consist of a hybrid of bacterial, eukaryotic, and uniquely archaeal mechanisms. We discuss this theme from the perspective of the role of individual transcription factors in genome-wide regulation, how these proteins interact to compile GRN topological structures, and how these topologies lead to emergent, high-level GRN functions. We conclude by discussing how systems biology approaches are a fruitful avenue for addressing remaining challenges, such as discovering gene function and the evolution of GRNs.
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Affiliation(s)
| | - Peter D Tonner
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.,Graduate Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina 27708, USA
| | - Cynthia L Darnell
- Department of Biology, Duke University, Durham, North Carolina 27708, USA
| | - Amy K Schmid
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.,Graduate Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina 27708, USA.,Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA;
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16
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McCarthy S, Ai C, Blum P. Enhancement of Metallosphaera sedula Bioleaching by Targeted Recombination and Adaptive Laboratory Evolution. ADVANCES IN APPLIED MICROBIOLOGY 2018; 104:135-165. [PMID: 30143251 DOI: 10.1016/bs.aambs.2018.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Thermophilic and lithoautotrophic archaea such as Metallosphaera sedula occupy acidic, metal-rich environments and are used in biomining processes. Biotechnological approaches could accelerate these processes and improve metal recovery by biomining organisms, but systems for genetic manipulation in these organisms are currently lacking. To gain a better understanding of the interplay between metal resistance, autotrophy, and lithotrophic metabolism, a genetic system was developed for M. sedula and used to evaluate parameters governing the efficiency of copper bioleaching. Additionally, adaptive laboratory evolution was used to select for naturally evolved M. sedula cell lines with desirable phenotypes for biomining, and these adapted cell lines were shown to have increased bioleaching capacity and efficiency. Genomic methods were used to analyze mutations that led to resistance in the experimentally evolved cell lines, while transcriptomics was used to examine changes in stress-inducible gene expression specific to the environmental conditions.
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Affiliation(s)
- Samuel McCarthy
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Chenbing Ai
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Paul Blum
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States.
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17
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Antonucci I, Gallo G, Limauro D, Contursi P, Ribeiro AL, Blesa A, Berenguer J, Bartolucci S, Fiorentino G. An ArsR/SmtB family member regulates arsenic resistance genes unusually arranged in Thermus thermophilus HB27. Microb Biotechnol 2017; 10:1690-1701. [PMID: 28696001 PMCID: PMC5658604 DOI: 10.1111/1751-7915.12761] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 01/01/2023] Open
Abstract
Arsenic resistance is commonly clustered in ars operons in bacteria; main ars operon components encode an arsenate reductase, a membrane extrusion protein, and an As‐sensitive transcription factor. In the As‐resistant thermophile Thermus thermophilus HB27, genes encoding homologues of these proteins are interspersed in the chromosome. In this article, we show that two adjacent genes, TtsmtB, encoding an ArsR/SmtB transcriptional repressor and, TTC0354, encoding a Zn2+/Cd2+‐dependent membrane ATPase are involved in As resistance; differently from characterized ars operons, the two genes are transcribed from dedicated promoters upstream of their respective genes, whose expression is differentially regulated at transcriptional level. Mutants defective in TtsmtB or TTC0354 are more sensitive to As than the wild type, proving their role in arsenic resistance. Recombinant dimeric TtSmtB binds in vitro to both promoters, but its binding capability decreases upon interaction with arsenate and, less efficiently, with arsenite. In vivo and in vitro experiments also demonstrate that the arsenate reductase (TtArsC) is subjected to regulation by TtSmtB. We propose a model for the regulation of As resistance in T. thermophilus in which TtSmtB is the arsenate sensor responsible for the induction of TtArsC which generates arsenite exported by TTC0354 efflux protein to detoxify cells.
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Affiliation(s)
- Immacolata Antonucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
| | - Giovanni Gallo
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
| | - Danila Limauro
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
| | - Patrizia Contursi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
| | - Ana Luisa Ribeiro
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alba Blesa
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - José Berenguer
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Simonetta Bartolucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
| | - Gabriella Fiorentino
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, 80126, Naples, Italy
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18
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Transcription Factor-Mediated Gene Regulation in Archaea. RNA METABOLISM AND GENE EXPRESSION IN ARCHAEA 2017. [DOI: 10.1007/978-3-319-65795-0_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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19
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Kim Y, Joachimiak G, Bigelow L, Babnigg G, Joachimiak A. How Aromatic Compounds Block DNA Binding of HcaR Catabolite Regulator. J Biol Chem 2016; 291:13243-56. [PMID: 27129205 DOI: 10.1074/jbc.m115.712067] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 11/06/2022] Open
Abstract
Bacterial catabolism of aromatic compounds from various sources including phenylpropanoids and flavonoids that are abundant in soil plays an important role in the recycling of carbon in the ecosystem. We have determined the crystal structures of apo-HcaR from Acinetobacter sp. ADP1, a MarR/SlyA transcription factor, in complexes with hydroxycinnamates and a specific DNA operator. The protein regulates the expression of the hca catabolic operon in Acinetobacter and related bacterial strains, allowing utilization of hydroxycinnamates as sole sources of carbon. HcaR binds multiple ligands, and as a result the transcription of genes encoding several catabolic enzymes is increased. The 1.9-2.4 Å resolution structures presented here explain how HcaR recognizes four ligands (ferulate, 3,4-dihydroxybenzoate, p-coumarate, and vanillin) using the same binding site. The ligand promiscuity appears to be an adaptation to match a broad specificity of hydroxycinnamate catabolic enzymes while responding to toxic thioester intermediates. Structures of apo-HcaR and in complex with a specific DNA hca operator when combined with binding studies of hydroxycinnamates show how aromatic ligands render HcaR unproductive in recognizing a specific DNA target. The current study contributes to a better understanding of the hca catabolic operon regulation mechanism by the transcription factor HcaR.
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Affiliation(s)
- Youngchang Kim
- From the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439
| | | | | | - Gyorgy Babnigg
- From the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439
| | - Andrzej Joachimiak
- From the Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, Argonne, Illinois 60439
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20
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Roy A, Ranjan A. HosA, a MarR Family Transcriptional Regulator, Represses Nonoxidative Hydroxyarylic Acid Decarboxylase Operon and Is Modulated by 4-Hydroxybenzoic Acid. Biochemistry 2016; 55:1120-34. [PMID: 26818787 DOI: 10.1021/acs.biochem.5b01163] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Members of the Multiple antibiotic resistance Regulator (MarR) family of DNA binding proteins regulate transcription of a wide array of genes required for virulence and pathogenicity of bacteria. The present study reports the molecular characterization of HosA (Homologue of SlyA), a MarR protein, with respect to its target gene, DNA recognition motif, and nature of its ligand. Through a comparative genomics approach, we demonstrate that hosA is in synteny with nonoxidative hydroxyarylic acid decarboxylase (HAD) operon and is present exclusively within the mutS-rpoS polymorphic region in nine different genera of Enterobacteriaceae family. Using molecular biology and biochemical approach, we demonstrate that HosA binds to a palindromic sequence downstream to the transcription start site of divergently transcribed nonoxidative HAD operon and represses its expression. Furthermore, in silico analysis showed that the recognition motif for HosA is highly conserved in the upstream region of divergently transcribed operon in different genera of Enterobacteriaceae family. A systematic chemical search for the physiological ligand revealed that 4-hydroxybenzoic acid (4-HBA) interacts with HosA and derepresses HosA mediated repression of the nonoxidative HAD operon. Based on our study, we propose a model for molecular mechanism underlying the regulation of nonoxidative HAD operon by HosA in Enterobacteriaceae family.
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Affiliation(s)
- Ajit Roy
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana 500001, India.,Graduate studies, Manipal University , Manipal 576104, India
| | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana 500001, India
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21
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Genetic Screen Reveals the Role of Purine Metabolism in Staphylococcus aureus Persistence to Rifampicin. Antibiotics (Basel) 2015; 4:627-42. [PMID: 27025643 PMCID: PMC4790316 DOI: 10.3390/antibiotics4040627] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/20/2015] [Accepted: 11/27/2015] [Indexed: 12/02/2022] Open
Abstract
Chronic infections with Staphylococcus aureus such as septicemia, osteomyelitis, endocarditis, and biofilm infections are difficult to treat because of persisters. Despite many efforts in understanding bacterial persistence, the mechanisms of persister formation in S. aureus remain elusive. Here, we performed a genome-wide screen of a transposon mutant library to study the molecular mechanisms involved in persistence of community-acquired S. aureus. Screening of the library for mutants defective in persistence or tolerance to rifampicin revealed many genes involved in metabolic pathways that are important for antibiotic persistence. In particular, the identified mutants belonged to metabolic pathways involved in carbohydrate, amino acid, lipid, vitamin and purine biosynthesis. Five mutants played a role in purine biosynthesis and two mutants, purB, an adenylosuccinate lyase, and purM, a phosphoribosylaminoimidazole synthetase, were selected for further confirmation. Mutants purB and purM showed defective persistence compared to the parental strain USA300 in multiple stress conditions including various antibiotics, low pH, and heat stress. The defect in persistence was restored by complementation with the wildtype purB and purM gene in the respective mutants. These findings provide new insights into the mechanisms of persistence in S. aureus and provide novel therapeutic targets for developing more effective treatment for persistent infections due to S. aureus.
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22
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Rudrappa D, Yao AI, White D, Pavlik BJ, Singh R, Facciotti MT, Blum P. Identification of an archaeal mercury regulon by chromatin immunoprecipitation. MICROBIOLOGY-SGM 2015; 161:2423-33. [PMID: 26408318 DOI: 10.1099/mic.0.000189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mercury is a heavy metal and toxic to all forms of life. Metal exposure can invoke a response to improve survival. In archaea, several components of a mercury response system have been identified, but it is not known whether metal transport is a member of this system. To identify such missing components, a peptide-tagged MerR transcription factor was used to localize enriched chromosome regions by chromosome immunoprecipitation combined with DNA sequence analysis. Such regions could serve as secondary regulatory binding sites to control the expression of additional genes associated with mercury detoxification. Among the 31 highly enriched loci, a subset of five was pursued as potential candidates based on their current annotations. Quantitative reverse transcription-PCR analysis of these regions with and without mercury treatment in WT and mutant strains lacking merR indicated significant regulatory responses under these conditions. Of these, a Family 5 extracellular solute-binding protein and the MarR transcription factor shown previously to control responses to oxidation were most strongly affected. Inactivation of the solute-binding protein by gene disruption increased the resistance of mutant cells to mercury challenge. Inductively coupled plasma-MS analysis of the mutant cell line following metal challenge indicated there was less intracellular mercury compared with the isogenic WT strain. Together, these regulated genes comprise new members of the archaeal MerR regulon and reveal a cascade of transcriptional control not previously demonstrated in this model organism.
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Affiliation(s)
- Deepak Rudrappa
- 1 School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Andrew I Yao
- 3 Department of Biomedical Engineering and Genome Center, University of California-Davis, Davis, California, USA
| | - Derrick White
- 1 School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Benjamin J Pavlik
- 2 Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Raghuveer Singh
- 1 School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Marc T Facciotti
- 3 Department of Biomedical Engineering and Genome Center, University of California-Davis, Davis, California, USA
| | - Paul Blum
- 1 School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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23
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Zhang Y, Luo F, Wu D, Hikichi Y, Kiba A, Igarashi Y, Ding W, Ohnishi K. PrhN, a putative marR family transcriptional regulator, is involved in positive regulation of type III secretion system and full virulence of Ralstonia solanacearum. Front Microbiol 2015; 6:357. [PMID: 25972849 PMCID: PMC4412082 DOI: 10.3389/fmicb.2015.00357] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/09/2015] [Indexed: 11/13/2022] Open
Abstract
The MarR-family of transcriptional regulators are involved in various cellular processes, including resistance to multiple antibiotics and other toxic chemicals, adaptation to different environments and pathogenesis in many plant and animal pathogens. Here, we reported a new MarR regulator PrhN, which was involved in the pathogenesis of Ralstonia solanacearum. prhN mutant exhibited significantly reduced virulence and stem colonization compared to that of wild type in tomato plants. prhN mutant caused identical hypersensitive response (HR) on resistant plants to the wild type. Deletion of prhN gene substantially reduced the expression of type III secretion system (T3SS) in vitro and in planta (mainly in tomato plants), which is essential for pathogenicity of R. solanacearum, and the complemented PrhN could restore its virulence and T3SS expression to that of wild type. T3SS is directly controlled by AraC-type transcriptional regulator HrpB, and the transcription of hrpB is activated by HrpG and PrhG. HrpG and PrhG are homologs but are regulated by the PhcA positively and negatively, respectively. Deletion of prhN gene also abolished the expression of hrpB and prhG, but didn't change the expression of hrpG and phcA. Together, these results indicated that PrhN positively regulates T3SS expression through PrhG and HrpB. PrhN and PhcA should regulate prhG expression in a parallel way. This is the first report on the pathogenesis of MarR regulator in R. solanacearum, and this new finding will improve our understanding on the various biological functions of MarR regulator and the complex regulatory network on hrp regulon in R. solanacearum.
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Affiliation(s)
- Yong Zhang
- Research Center of Bioenergy and Bioremediation, Southwest University Chongqing, China
| | - Feng Luo
- Research Center of Bioenergy and Bioremediation, Southwest University Chongqing, China
| | - Dousheng Wu
- College of Plant Protection, Southwest University Chongqing, China
| | - Yasufumi Hikichi
- Laboratory of Plant Pathology and Biotechnology, Kochi University Kochi, Japan
| | - Akinori Kiba
- Laboratory of Plant Pathology and Biotechnology, Kochi University Kochi, Japan
| | - Yasuo Igarashi
- Research Center of Bioenergy and Bioremediation, Southwest University Chongqing, China
| | - Wei Ding
- College of Plant Protection, Southwest University Chongqing, China
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University Kochi, Japan
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Shu HY, Lin LC, Lin TK, Chen HP, Yang HH, Peng KC, Lin GH. Transcriptional regulation of the iac locus from Acinetobacter baumannii by the phytohormone indole-3-acetic acid. Antonie van Leeuwenhoek 2015; 107:1237-47. [PMID: 25726082 DOI: 10.1007/s10482-015-0417-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/24/2015] [Indexed: 11/25/2022]
Abstract
The iac locus is involved in indole-3-acetic acid (IAA) catabolism in Acinetobacter baumannii. Nine structural genes of iac are transcribed in the same direction, whereas iacR, which encodes a MarR-type transcriptional regulator, is transcribed in the opposite direction. The IacA protein, which is encoded by the second structural gene of the iac locus, is expressed in an IAA-dependent manner. Here, we characterized gene expression from this locus in wild type A. baumannii and in an iacR mutant; this revealed that the iacH promoter is negatively regulated by IacR. The transcriptional site of iacH was determined by using 5' rapid amplification of cDNA ends; one IacR-binding site was identified between positions -35 and +28 of the iacH promoter. Sequence analysis and an electrophoretic mobility shift assay indicated that recombinant IacR binds specifically to a sequence with dyad symmetry in the iacR-iacH overlapping promoters in the absence of IAA. In addition, a two-plasmid expression system in Escherichia coli showed that IAA probably serves as a ligand that binds to IacR and releases it from the iacH promoter, thereby allowing RNA polymerase to transcribe iac. Thus, iac is expressed in order to promote IAA degradation, whereas free IacR is required for iac repression. We conclude that IacR serves as a key regulator of IAA degradation in A. baumannii in the rhizosphere. These results provide new insights into the possible role of A. baumannii in the environment.
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Affiliation(s)
- Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan, 711, Taiwan
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Analysis of the xplAB-containing gene cluster involved in the bacterial degradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine. Appl Environ Microbiol 2014; 80:6601-10. [PMID: 25128343 DOI: 10.1128/aem.01818-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Repeated use of the explosive compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) on military land has resulted in significant soil and groundwater pollution. Rates of degradation of RDX in the environment are low, and accumulated RDX, which the U.S. Environmental Protection Agency has determined is a possible human carcinogen, is now threatening drinking water supplies. RDX-degrading microorganisms have been isolated from RDX-contaminated land; however, despite the presence of these species in contaminated soils, RDX pollution persists. To further understand this problem, we studied RDX-degrading species belonging to four different genera (Rhodococcus, Microbacterium, Gordonia, and Williamsia) isolated from geographically distinct locations and established that the xplA and xplB (xplAB) genes, which encode a cytochrome P450 and a flavodoxin redox partner, respectively, are nearly identical in all these species. Together, the xplAB system catalyzes the reductive denitration of RDX and subsequent ring cleavage under aerobic and anaerobic conditions. In addition to xplAB, the Rhodococcus species studied here share a 14-kb region flanking xplAB; thus, it appears likely that the RDX-metabolizing ability was transferred as a genomic island within a transposable element. The conservation and transfer of xplAB-flanking genes suggest a role in RDX metabolism. We therefore independently knocked out genes within this cluster in the RDX-degrading species Rhodococcus rhodochrous 11Y. Analysis of the resulting mutants revealed that XplA is essential for RDX degradation and that XplB is not the sole contributor of reducing equivalents to XplA. While XplA expression is induced under nitrogen-limiting conditions and further enhanced by the presence of RDX, MarR is not regulated by RDX.
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Role of an archaeal PitA transporter in the copper and arsenic resistance of Metallosphaera sedula, an extreme thermoacidophile. J Bacteriol 2014; 196:3562-70. [PMID: 25092032 DOI: 10.1128/jb.01707-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Thermoacidophilic archaea, such as Metallosphaera sedula, are lithoautotrophs that occupy metal-rich environments. In previous studies, an M. sedula mutant lacking the primary copper efflux transporter, CopA, became copper sensitive. In contrast, the basis for supranormal copper resistance remained unclear in the spontaneous M. sedula mutant, CuR1. Here, transcriptomic analysis of copper-shocked cultures indicated that CuR1 had a unique regulatory response to metal challenge corresponding to the upregulation of 55 genes. Genome resequencing identified 17 confirmed mutations unique to CuR1 that were likely to change gene function. Of these, 12 mapped to genes with annotated function associated with transcription, metabolism, or transport. These mutations included 7 nonsynonymous substitutions, 4 insertions, and 1 deletion. One of the insertion mutations mapped to pseudogene Msed_1517 and extended its reading frame an additional 209 amino acids. The extended mutant allele was identified as a homolog of Pho4, a family of phosphate symporters that includes the bacterial PitA proteins. Orthologs of this allele were apparent in related extremely thermoacidophilic species, suggesting M. sedula naturally lacked this gene. Phosphate transport studies combined with physiologic analysis demonstrated M. sedula PitA was a low-affinity, high-velocity secondary transporter implicated in copper resistance and arsenate sensitivity. Genetic analysis demonstrated that spontaneous arsenate-resistant mutants derived from CuR1 all underwent mutation in pitA and nonselectively became copper sensitive. Taken together, these results point to archaeal PitA as a key requirement for the increased metal resistance of strain CuR1 and its accelerated capacity for copper bioleaching.
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Conformational stability and ligand binding properties of BldR, a member of the MarR family, from Sulfolobus solfataricus. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1167-72. [PMID: 24704039 DOI: 10.1016/j.bbapap.2014.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/07/2014] [Accepted: 03/26/2014] [Indexed: 12/19/2022]
Abstract
The multiple antibiotic resistance regulators (MarR) constitute a family of ligand-responsive transcriptional regulators ubiquitous among the bacterial and archaeal domains. BldR, an archaeal MarR member characterized from the hyperthermophilic crenarchaeon Sulfolobus solfataricus regulates its own expression and that of an alcohol dehydrogenase gene by binding to sequences in their promoters and responding to benzaldehyde as the effector molecule. In this study we assessed the thermodynamic stability of the protein BldR and its binding with benzaldehyde through biophysical measurements. The temperature- and denaturant-induced unfolding experiments, performed by means of circular dichroism (CD) and differential scanning calorimetry (DSC), showed that BldR has an extremely high thermal stability (Td=108.9°C) and a remarkable resistance against GuHCl (Cm=5.3M at 25°C). The unfolding Gibbs energy, ΔdG (H2O), calculated by the linear extrapolation model from GuHCl-induced unfolding equilibrium curve, is 72.2kJmol(-1). ITC binding experiments showed that four benzaldehyde molecules bind to one BldR dimer with a binding constant Kb of 7.5·10(5)M(-1), being the binding entropically driven. ITC, CD and fluorescence results are consistent with a conformational change induced by benzaldehyde binding, further proving that this molecule is a specific effector for BldR modulating its DNA binding activity.
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Contursi P, Fusco S, Limauro D, Fiorentino G. Host and viral transcriptional regulators in Sulfolobus: an overview. Extremophiles 2013; 17:881-95. [PMID: 24085522 DOI: 10.1007/s00792-013-0586-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 09/16/2013] [Indexed: 12/29/2022]
Abstract
The genus Sulfolobus includes microorganisms belonging to the domain Archaea, sub-kingdom Crenarchaeota, living in geographically distant acidic hot springs. Their adaptation to such particular habitats requires finely regulated mechanisms of gene expression, among which, those modulated by sequence-specific transcription factors (TFs) play a key role. In this review, we summarize the current knowledge on the repertoires of TFs found in Sulfolobus spp. and their viruses, focusing on the description of their DNA-binding domains and their structure-function relationship.
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Affiliation(s)
- Patrizia Contursi
- Dipartimento di Biologia, Università di Napoli Federico II, via Cinthia, Edificio 7, 80126, Napoli, Italy
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Del Giudice I, Limauro D, Pedone E, Bartolucci S, Fiorentino G. A novel arsenate reductase from the bacterium Thermus thermophilus HB27: its role in arsenic detoxification. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2071-9. [PMID: 23800470 DOI: 10.1016/j.bbapap.2013.06.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/11/2013] [Accepted: 06/15/2013] [Indexed: 11/16/2022]
Abstract
Microorganisms living in arsenic-rich geothermal environments act on arsenic with different biochemical strategies, but the molecular mechanisms responsible for the resistance to the harmful effects of the metalloid have only partially been examined. In this study, we investigated the mechanisms of arsenic resistance in the thermophilic bacterium Thermus thermophilus HB27. This strain, originally isolated from a Japanese hot spring, exhibited tolerance to concentrations of arsenate and arsenite up to 20mM and 15mM, respectively; it owns in its genome a putative chromosomal arsenate reductase (TtarsC) gene encoding a protein homologous to the one well characterized from the plasmid pI258 of the Gram+bacterium Staphylococcus aureus. Differently from the majority of microorganisms, TtarsC is part of an operon including genes not related to arsenic resistance; qRT-PCR showed that its expression was four-fold increased when arsenate was added to the growth medium. The gene cloning and expression in Escherichia coli, followed by purification of the recombinant protein, proved that TtArsC was indeed a thioredoxin-coupled arsenate reductase with a kcat/KM value of 1.2×10(4)M(-1)s(-1). It also exhibited weak phosphatase activity with a kcat/KM value of 2.7×10(-4)M(-1)s(-1). The catalytic role of the first cysteine (Cys7) was ascertained by site-directed mutagenesis. These results identify TtArsC as an important component in the arsenic resistance in T. thermophilus giving the first structural-functional characterization of a thermophilic arsenate reductase.
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Affiliation(s)
- Immacolata Del Giudice
- Department of Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
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Protein photocrosslinking reveals dimer of dimers formation on MarR protein in Escherichia coli. Sci China Chem 2011. [DOI: 10.1007/s11426-011-4437-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Guerra AJ, Dann CE, Giedroc DP. Crystal structure of the zinc-dependent MarR family transcriptional regulator AdcR in the Zn(II)-bound state. J Am Chem Soc 2011; 133:19614-7. [PMID: 22085181 DOI: 10.1021/ja2080532] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Streptococcus pneumoniae adhesin competence regulator (AdcR), the first metal-dependent member of the multiple antibiotic resistance regulator (MarR) family of proteins, represses the transcription of a high-affinity zinc-specific uptake transporter, a group of surface antigen zinc-binding pneumococcal histidine triad proteins (PhtA, PhtB, PhtD, and PhtE), and an AdcA homologue (AdcAII). The 2.0 Å resolution structure of Zn(II)-bound AdcR reveals a highly helical two-fold-symmetric dimer with two distinct metal-binding sites per protomer. Zn(II) is tetrahedrally coordinated by E24, H42, H108, and H112 in what defines the primary sensing site in AdcR. Site 2 is a tetracoordinate site whose function is currently unknown. NMR methyl group perturbation experiments reveal that Zn(II) drives a global change in the structure of apo-AdcR that stabilizes a conformation that is compatible with DNA binding. This co-repression mechanism is unprecedented in MarR transcriptional regulators.
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Affiliation(s)
- Alfredo J Guerra
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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Abstract
Archaea represent an important and vast domain of life. This cellular domain includes a large diversity of organisms characterized as prokaryotes with basal transcriptional machinery similar to eukarya. In this work we explore the most recent findings concerning the transcriptional regulatory organization in archaeal genomes since the perspective of the DNA-binding transcription factors (TFs), such as the high proportion of archaeal TFs homologous to bacteria, the apparent deficit of TFs, only comparable to the proportion of TFs in parasites or intracellular pathogenic bacteria, suggesting a deficit in this class of proteins. We discuss an appealing hypothesis to explain the apparent deficit of TFs in archaea, based on their characteristics, such as their small length sizes. The hypothesis suggests that a large fraction of these small-sized TFs could supply the deficit of TFs in archaea, by forming different combinations of monomers similar to that observed in eukaryotic transcriptional machinery, where a wide diversity of protein-protein interactions could act as mediators of regulatory feedback, indicating a chimera of bacterial and eukaryotic TFs' functionality. Finally, we discuss how global experiments can help to understand in a global context the role of TFs in these organisms.
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Fiorentino G, Del Giudice I, Bartolucci S, Durante L, Martino L, Del Vecchio P. Identification and Physicochemical Characterization of BldR2 from Sulfolobus solfataricus, a Novel Archaeal Member of the MarR Transcription Factor Family. Biochemistry 2011; 50:6607-21. [DOI: 10.1021/bi200187j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriella Fiorentino
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Immacolata Del Giudice
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Simonetta Bartolucci
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Lorenzo Durante
- Department of Chemistry “Paolo Corradini”, University of Naples Federico II, via Cinthia, 80126 Naples, Italy
| | - Luigi Martino
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, U.K
| | - Pompea Del Vecchio
- Department of Chemistry “Paolo Corradini”, University of Naples Federico II, via Cinthia, 80126 Naples, Italy
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C68 from the Sulfolobus islandicus plasmid-virus pSSVx is a novel member of the AbrB-like transcription factor family. Biochem J 2011; 435:157-66. [PMID: 21208189 DOI: 10.1042/bj20101334] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The genetic element pSSVx from Sulfolobus islandicus, strain REY15/4, is a hybrid between a plasmid and a fusellovirus. This plasmid-virus hybrid infects several species of the hyperthermophilic acidophilic crenarchaeon Sulfolobus. The open reading frame orfc68 of pSSVx encodes a 7.7 kDa protein that does not show significant sequence homology with any protein with known three-dimensional structure. EMSA (electrophoretic mobility-shift assay) experiments, DNA footprinting and CD analyses indicate that recombinant C68, purified from Escherichia coli, binds to two different operator sites that are located upstream of its own promoter. The three-dimensional structure, solved by a single-wavelength anomalous diffraction experiment on a selenomethionine derivative, shows that the protein assumes a swapped-hairpin fold, which is a distinctive fold associated with a family of prokaryotic transcription factors, such as AbrB from Bacillus subtilis. Nevertheless, C68 constitutes a novel representative of this family because it shows several peculiar structural and functional features.
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Abstract
Sulfolobus solfataricus and Sulfolobus islandicus contain several genes exhibiting D-arabinose-inducible expression and these systems are ideal for studying mechanisms of archaeal gene expression. At sequence level, only two highly conserved cis elements are present on the promoters: a regulatory element named ara box directing arabinose-inducible expression and the basal promoter element TATA, serving as the binding site for the TATA-binding protein. Strikingly, these promoters possess a modular structure that allows an essentially inactive basal promoter to be strongly activated. The invoked mechanisms include TFB (transcription factor B) recruitment by the ara-box-binding factor to activate gene expression and modulation of TFB recruitment efficiency to yield differential gene expression.
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A transcriptional regulator and ABC transporters link stress tolerance, (p)ppGpp, and genetic competence in Streptococcus mutans. J Bacteriol 2010; 193:862-74. [PMID: 21148727 DOI: 10.1128/jb.01257-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans, a primary agent of dental caries, has three (p)ppGpp synthases: RelA, which is required for a mupirocin-induced stringent response; RelP, which produces (p)ppGpp during exponential growth and is regulated by the RelRS two-component system; and RelQ. Transcription of relPRS and a gene cluster (SMu0835 to SMu0837) located immediately upstream was activated in cells grown with aeration and during a stringent response, respectively. Bioinformatic analysis predicted that SMu0836 and SMu0837 encode ABC exporters, which we designated rcrPQ (rel competence-related) genes, respectively. SMu0835 (rcrR) encodes a MarR family transcriptional regulator. Reverse transcriptase PCR (RT-PCR) and quantitative RT-PCR analysis showed that RcrR functions as an autogenous negative regulator of the expression of the rcrRPQ operon. A mutant in which a polar insertion replaced the SMu836 gene (Δ836polar) grew more slowly and had final yields that were lower than those of the wild-type strain. Likewise, the Δ836polar strain had an impaired capacity to form biofilms, grew poorly at pH 5.5, and was more sensitive to oxidative stressors. Optimal expression of rcrPQ required RelP and vice versa. Replacement of rcrR with a nonpolar antibiotic resistance marker (Δ835np), which leads to overexpression of rcrPQ, yielded a strain that was not transformable with exogenous DNA. Transcriptional analysis revealed that the expression of comYA and comX was dramatically altered in the Δ835np and Δ836polar mutants. Collectively, the data support the suggestion that the rcrRPQ gene products play a critical role in physiologic homeostasis and stress tolerance by linking (p)ppGpp metabolism, acid and oxidative stress tolerance, and genetic competence.
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GlpR represses fructose and glucose metabolic enzymes at the level of transcription in the haloarchaeon Haloferax volcanii. J Bacteriol 2010; 192:6251-60. [PMID: 20935102 DOI: 10.1128/jb.00827-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, a DeoR/GlpR-type transcription factor was investigated for its potential role as a global regulator of sugar metabolism in haloarchaea, using Haloferax volcanii as a model organism. Common to a number of haloarchaea and Gram-positive bacterial species, the encoding glpR gene was chromosomally linked with genes of sugar metabolism. In H. volcanii, glpR was cotranscribed with the downstream phosphofructokinase (PFK; pfkB) gene, and the transcript levels of this glpR-pfkB operon were 10- to 20-fold higher when cells were grown on fructose or glucose than when they were grown on glycerol alone. GlpR was required for repression on glycerol based on significant increases in the levels of PFK (pfkB) transcript and enzyme activity detected upon deletion of glpR from the genome. Deletion of glpR also resulted in significant increases in both the activity and the transcript (kdgK1) levels of 2-keto-3-deoxy-D-gluconate kinase (KDGK), a key enzyme of haloarchaeal glucose metabolism, when cells were grown on glycerol, compared to the levels obtained for media with glucose. Promoter fusions to a β-galactosidase bgaH reporter revealed that transcription of glpR-pfkB and kdgK1 was modulated by carbon source and GlpR, consistent with quantitative reverse transcription-PCR (qRT-PCR) and enzyme activity assays. The results presented here provide genetic and biochemical evidence that GlpR controls both fructose and glucose metabolic enzymes through transcriptional repression of the glpR-pfkB operon and kdgK1 during growth on glycerol.
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Perera IC, Grove A. Molecular mechanisms of ligand-mediated attenuation of DNA binding by MarR family transcriptional regulators. J Mol Cell Biol 2010; 2:243-54. [PMID: 20716550 DOI: 10.1093/jmcb/mjq021] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Bacteria and archaea encode members of the large multiple antibiotic resistance regulator (MarR) family of transcriptional regulators. Generally, MarR homologs regulate activity of genes involved in antibiotic resistance, stress responses, virulence or catabolism of aromatic compounds. They constitute a diverse group of transcriptional regulators that includes both repressors and activators, and the conventional mode of regulation entails a genetic locus in which the MarR homolog and a gene under its regulation are encoded divergently; binding of the MarR homolog to the intergenic region typically represses transcription of both genes, while binding of a specific ligand to the transcription factor results in attenuated DNA binding and hence activated gene expression. For many homologs, the natural ligand is unknown. Crystal structures reveal a common architecture with a characteristic winged helix domain for DNA binding, and recent structural information of homologs solved both in the absence and presence of their respective ligands, as well as biochemical data, is finally converging to illuminate the mechanisms by which ligand-binding causes attenuated DNA binding. As MarR homologs regulate pathways that are critical to bacterial physiology, including virulence, a molecular understanding of mechanisms by which ligands affect a regulation of gene activity is essential. Specifying the position of ligand-binding pockets further has the potential to aid in identifying the ligands for MarR homologs for which the ligand remains unknown.
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Affiliation(s)
- Inoka C Perera
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Fernandez A, Lechardeur D, Derré-Bobillot A, Couvé E, Gaudu P, Gruss A. Two coregulated efflux transporters modulate intracellular heme and protoporphyrin IX availability in Streptococcus agalactiae. PLoS Pathog 2010; 6:e1000860. [PMID: 20421944 PMCID: PMC2858704 DOI: 10.1371/journal.ppat.1000860] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 03/16/2010] [Indexed: 01/01/2023] Open
Abstract
Streptococcus agalactiae is a major neonatal pathogen whose infectious route involves septicemia. This pathogen does not synthesize heme, but scavenges it from blood to activate a respiration metabolism, which increases bacterial cell density and is required for full virulence. Factors that regulate heme pools in S. agalactiae are unknown. Here we report that one main strategy of heme and protoporphyrin IX (PPIX) homeostasis in S. agalactiae is based on a regulated system of efflux using two newly characterized operons, gbs1753 gbs1752 (called pefA pefB), and gbs1402 gbs1401 gbs1400 (called pefR pefC pefD), where pef stands for 'porphyrin-regulated efflux'. In vitro and in vivo data show that PefR, a MarR-superfamily protein, is a repressor of both operons. Heme or PPIX both alleviate PefR-mediated repression. We show that bacteria inactivated for both Pef efflux systems display accrued sensitivity to these porphyrins, and give evidence that they accumulate intracellularly. The DeltapefR mutant, in which both pef operons are up-regulated, is defective for heme-dependent respiration, and attenuated for virulence. We conclude that this new efflux regulon controls intracellular heme and PPIX availability in S. agalactiae, and is needed for its capacity to undergo respiration metabolism, and to infect the host.
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Affiliation(s)
- Annabelle Fernandez
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
- * E-mail: (AF); (AG)
| | - Delphine Lechardeur
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Aurélie Derré-Bobillot
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Elisabeth Couvé
- Institut Pasteur, Laboratoire Evolution et Génomique Bactérienne, CNRS URA 2171, Paris, France
| | - Philippe Gaudu
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
| | - Alexandra Gruss
- Institut National de la Recherche Agronomique, UMR1319 Micalis, Bâtiment 222, Domaine de Vilvert, Jouy-en-Josas, France
- * E-mail: (AF); (AG)
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Krastel K, Senadheera DB, Mair R, Downey JS, Goodman SD, Cvitkovitch DG. Characterization of a glutamate transporter operon, glnQHMP, in Streptococcus mutans and its role in acid tolerance. J Bacteriol 2010; 192:984-93. [PMID: 20023025 PMCID: PMC2812961 DOI: 10.1128/jb.01169-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 12/07/2009] [Indexed: 12/11/2022] Open
Abstract
Glutamate contributes to the acid tolerance response (ATR) of many Gram-negative and Gram-positive bacteria, but its role in the ATR of the oral bacterium Streptococcus mutans is unknown. This study describes the discovery and characterization of a glutamate transporter operon designated glnQHMP (Smu.1519 to Smu.1522) and investigates its potential role in acid tolerance. Deletion of glnQHMP resulted in a 95% reduction in transport of radiolabeled glutamate compared to the wild-type UA159 strain. The addition of glutamate to metabolizing UA159 cells resulted in an increased production of acidic end products, whereas the glnQHMP mutant produced less lactic acid than UA159, suggesting a link between glutamate metabolism and acid production and possible acid tolerance. To investigate this possibility, we conducted a microarray analysis with glutamate and under pH 5.5 and pH 7.5 conditions which showed that expression of the glnQHMP operon was downregulated by both glutamate and mild acid. We also measured the growth kinetics of UA159 and its glnQHMP-negative derivative at pH 5.5 and found that the mutant doubled at a much slower rate than the parent strain but survived at pH 3.5 significantly better than the wild type. Taken together, these findings support the involvement of the glutamate transporter operon glnQHMP in the acid tolerance response in S. mutans.
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Affiliation(s)
- Kirsten Krastel
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Dilani B. Senadheera
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Richard Mair
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Jennifer S. Downey
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Steven D. Goodman
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
| | - Dennis G. Cvitkovitch
- Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, Ontario M5G 1G6, Canada, Division of Diagnostic Sciences and Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089
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Yu L, Fang J, Wei Y. Characterization of the ligand and DNA binding properties of a putative archaeal regulator ST1710. Biochemistry 2009; 48:2099-108. [PMID: 19166356 DOI: 10.1021/bi801662s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While a rich collection of bacterium-like regulating proteins has been identified in the archaeal genome, few of them have been studied at the molecular level. In this study, we characterized the ligand and DNA binding properties of a putative regulator ST1710 from the archaeon Sulfolobus tokodaii. ST1710 is homologous to the multiple-antibiotic resistance repressor (MarR) family bacterial regulators. The protein consists of a ligand binding site, partially overlapping with a winged helix-turn-helix DNA binding site. We characterized the interactions between ST1710 and three ligands, salicylate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and ethidium, which bind to bacterial MarRs. The binding affinities of the ligands for ST1710 were comparable to their affinities for the bacterial MarRs. The ligand binding was temperature sensitive and caused conformational changes in ST1710. To investigate the effect of ligand binding on the interaction between ST1710 and DNA, we fluorescently labeled a 47mer dsDNA (ST1) containing a putative ST1710 recognition site and determined the dissociation constant between ST1 and ST1710 using the fluorescence polarization method. The binding affinity almost doubled from 10 degrees C (Kd = 618 +/- 34 nM) to 30 degreesC (Kd = 334 +/- 15 nM), and again from 30 to 50 degrees C (Kd = 189 +/- 9 nM). This result suggests that under the natural living condition (80 degrees C) of S. tokodaii, the binding affinity might increase even further. The presence of CCCP and salicylate suppressed ST1710-ST1 interaction, indicating that ST1710 functioned as a repressor.
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Affiliation(s)
- Linliang Yu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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Peng N, Xia Q, Chen Z, Liang YX, She Q. An upstream activation element exerting differential transcriptional activation on an archaeal promoter. Mol Microbiol 2009; 74:928-39. [PMID: 19818017 DOI: 10.1111/j.1365-2958.2009.06908.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Microorganisms can utilize different sugars as energy and carbon sources and the genes involved in sugar metabolism often exhibit highly regulated expression. To study cis-acting elements controlling arabinose-responsive expression in archaea, the promoter of the Sulfolobus solfataricus araS gene encoding an arabinose binding protein was characterized using an Sulfolobus islandicus reporter gene system. The minimal active araS promoter (P(araS)) was found to be 59 nucleotides long and harboured four promoter elements: an ara-box, an upstream transcription factor B-responsive element (BRE), a TATA-box and a proximal promoter element, each of which contained important nucleotides that either greatly decreased or completely abolished promoter activity upon mutagenesis. The basal araS promoter was virtually inactive due to intrinsically weak BRE element, and the upstream activating sequence (UAS) ara-box activated the basal promoter by recruiting transcription factor B to its BRE. While this UAS ensured a general expression from an inactive or weak basal promoter in the presence of other tested carbon resources, it exhibited a strong arabinose-responsive transcriptional activation. To our knowledge, this represents the first example of an archaeal UAS that exhibits differential activation to the expression on the same promoter in the presence of different carbon sources.
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Affiliation(s)
- Nan Peng
- State key laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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43
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Li C, Roege KE, Kelly WL. Analysis of the Indanomycin Biosynthetic Gene Cluster fromStreptomyces antibioticusNRRL 8167. Chembiochem 2009; 10:1064-72. [DOI: 10.1002/cbic.200800822] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Di Fiore A, Fiorentino G, Vitale RM, Ronca R, Amodeo P, Pedone C, Bartolucci S, De Simone G. Structural analysis of BldR from Sulfolobus solfataricus provides insights into the molecular basis of transcriptional activation in Archaea by MarR family proteins. J Mol Biol 2009; 388:559-69. [PMID: 19298823 DOI: 10.1016/j.jmb.2009.03.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 03/10/2009] [Accepted: 03/11/2009] [Indexed: 11/28/2022]
Abstract
The multiple antibiotic resistance regulator (MarR) family constitutes a significant class of transcriptional regulators whose members control a variety of important biological functions such as regulation of response to environmental stress, control of virulence factor production, resistance to antimicrobial agents, and regulation of aromatic catabolic pathways. Although the majority of MarR family members have been characterized as transcriptional repressors, a few examples of transcriptional activators have also been reported. BldR is a newly identified member of this family that has been demonstrated to act as a transcriptional activator in stress response to aromatic compounds in the crenarchaeon Sulfolobus solfataricus. In this work, we report findings on the BldR X-ray crystal structure and present a molecular modeling study on the complex that this protein forms with its cognate DNA sequence, thus providing the first detailed description of the DNA-binding mechanism of an archaeal activator belonging to the MarR family. Two residues responsible for the high binding specificity of this transcriptional regulator were also identified. Our studies demonstrated that, in Archaea, the capability of MarR family members to act as activators or repressors is not related to a particular DNA-binding mechanism but rather could be due to the position of the binding site on the target DNA. Moreover, since genes encoding MarR proteins often control transcription of operons that encode for multisubstrate efflux pumps, our results also provided important insights for the identification of new tools to overcome the microorganism's multidrug resistance.
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Affiliation(s)
- Anna Di Fiore
- Istituto di Biostrutture e Bioimmagini-CNR, via Mezzocannone 16, Naples, Italy
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A novel E. coli biosensor for detecting aromatic aldehydes based on a responsive inducible archaeal promoter fused to the green fluorescent protein. Appl Microbiol Biotechnol 2009; 82:67-77. [DOI: 10.1007/s00253-008-1771-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 10/23/2008] [Accepted: 10/25/2008] [Indexed: 10/21/2022]
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