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Harzallah B, Grama SB, Bousseboua H, Jouanneau Y, Yang J, Li J. Isolation and characterization of Indigenous Bacilli strains from an oil refinery wastewater with potential applications for phenol/cresol bioremediation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 332:117322. [PMID: 36724594 DOI: 10.1016/j.jenvman.2023.117322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/07/2023] [Accepted: 01/15/2023] [Indexed: 06/18/2023]
Abstract
Phenolic compounds are frequently occurring in wastewaters from various industrial processes at high concentrations, imposing prominent risk to aquatic biosphere and human health. Bioremediation has been proven to be an effective approach to remove these compounds, and hunting for functional organisms is still of primary importance to develop efficient processes. In this study, we report several newly isolated bacillus strains with superior performances in metabolizing phenols, one of which showed paramount efficiencies to metabolize phenol at concentrations up to 1200 mg L-1 and could simultaneously degrade a wide range of other phenolic compounds. The genes encoding for phenol hydroxylase (PH) and catechol-2,3-dioxygenase (C23O) have been detected and characterized, evidencing that phenol degradation occurs via the meta pathway. The GC level of the PH gene was found to be much higher than that of genes from other Bacilli but was quite close to that of the genes from Rhodococcus, and the induction of both enzymes by phenols was confirmed by RT-PCR experiments. We intend to believe this novel strain might be promising to serve as preferred organisms for developing more robust and efficient bioremediation processes of degrading phenolic compounds due to its validated performance.
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Affiliation(s)
- Besma Harzallah
- CEA, DRF, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38054, France; CNRS, UMR 5249, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38054, France; Université Grenoble Alpes, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France; Université des Frères Mentouri, Laboratoire de Génie Microbiologique et Applications, Constantine 25117, Algeria
| | - Samir B Grama
- Laboratory of Natural Substances, Biomolecules and Biotechnological Applications, University of Oum El Bouaghi, Oum El Bouaghi 04000, Algeria.
| | - Hacène Bousseboua
- Ecole Nationale Supérieure de Biotechnologies, Constantine 25000, Algeria
| | - Yves Jouanneau
- CEA, DRF, IRIG, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38054, France; CNRS, UMR 5249, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38054, France; Université Grenoble Alpes, Laboratoire de Chimie et Biologie des Métaux, Grenoble F-38000, France
| | - Jixiang Yang
- Chongqing Institute of Green and Intelligence Technology, Chinese Academy of Science, Chongqing 400714, China
| | - Jian Li
- College of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, China.
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2
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Li F, Zhao Y, Xue L, Ma F, Dai SY, Xie S. Microbial lignin valorization through depolymerization to aromatics conversion. Trends Biotechnol 2022; 40:1469-1487. [PMID: 36307230 DOI: 10.1016/j.tibtech.2022.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 11/05/2022]
Abstract
Lignin is the most abundant source of renewable aromatic biopolymers and its valorization presents significant value for biorefinery sustainability, which promotes the utilization of renewable resources. However, it is challenging to fully convert the structurally complex, heterogeneous, and recalcitrant lignin into high-value products. The in-depth research on the lignin degradation mechanism, microbial metabolic pathways, and rational design of new systems using synthetic biology have significantly accelerated the development of lignin valorization. This review summarizes the key enzymes involved in lignin depolymerization, the mechanisms of microbial lignin conversion, and the lignin valorization application with integrated systems and synthetic biology. Current challenges and future strategies to further study lignin biodegradation and the trends of lignin valorization are also discussed.
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Affiliation(s)
- Fei Li
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yiquan Zhao
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Le Xue
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Fuying Ma
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Susie Y Dai
- Department of Plant Pathology and Microbiology, Texas A&M University, College station, TX 77843, USA.
| | - Shangxian Xie
- Department of Biotechnology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
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3
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Zharikova NV, Korobov VV, Zhurenko EI. Flavin-Dependent Monooxygenases Involved in Bacterial Degradation of Chlorophenols. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822060175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Aliyu H, de Maayer P, Neumann A. Not All That Glitters Is Gold: The Paradox of CO-dependent Hydrogenogenesis in Parageobacillus thermoglucosidasius. Front Microbiol 2021; 12:784652. [PMID: 34956151 PMCID: PMC8696081 DOI: 10.3389/fmicb.2021.784652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/05/2021] [Indexed: 11/13/2022] Open
Abstract
The thermophilic bacterium Parageobacillus thermoglucosidasius has recently gained interest due to its ability to catalyze the water gas shift reaction, where the oxidation of carbon monoxide (CO) is linked to the evolution of hydrogen (H2) gas. This phenotype is largely predictable based on the presence of a genomic region coding for a carbon monoxide dehydrogenase (CODH—Coo) and hydrogen evolving hydrogenase (Phc). In this work, seven previously uncharacterized strains were cultivated under 50% CO and 50% air atmosphere. Despite the presence of the coo—phc genes in all seven strains, only one strain, Kp1013, oxidizes CO and yields H2. The genomes of the H2 producing strains contain unique genomic regions that code for proteins involved in nickel transport and the detoxification of catechol, a by-product of a siderophore-mediated iron acquisition system. Combined, the presence of these genomic regions could potentially drive biological water gas shift (WGS) reaction in P. thermoglucosidasius.
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Affiliation(s)
- Habibu Aliyu
- Institute of Process Engineering in Life Science 2 - Technical Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Pieter de Maayer
- School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Anke Neumann
- Institute of Process Engineering in Life Science 2 - Technical Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Mascotti ML, Juri Ayub M, Fraaije MW. On the diversity of F 420 -dependent oxidoreductases: A sequence- and structure-based classification. Proteins 2021; 89:1497-1507. [PMID: 34216160 PMCID: PMC8518648 DOI: 10.1002/prot.26170] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/30/2021] [Accepted: 06/26/2021] [Indexed: 11/05/2022]
Abstract
The F420 deazaflavin cofactor is an intriguing molecule as it structurally resembles the canonical flavin cofactor, although behaves as a nicotinamide cofactor due to its obligate hydride-transfer reactivity and similar low redox potential. Since its discovery, numerous enzymes relying on it have been described. The known deazaflavoproteins are taxonomically restricted to Archaea and Bacteria. The biochemistry of the deazaflavoenzymes is diverse and they exhibit great structural variability. In this study a thorough sequence and structural homology evolutionary analysis was performed in order to generate an overarching classification of the F420 -dependent oxidoreductases. Five different deazaflavoenzyme Classes (I-V) are described according to their structural folds as follows: Class I encompassing the TIM-barrel F420 -dependent enzymes; Class II including the Rossmann fold F420 -dependent enzymes; Class III comprising the β-roll F420 -dependent enzymes; Class IV which exclusively gathers the SH3 barrel F420 -dependent enzymes and Class V including the three layer ββα sandwich F420 -dependent enzymes. This classification provides a framework for the identification and biochemical characterization of novel deazaflavoenzymes.
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Affiliation(s)
- María Laura Mascotti
- Molecular Enzymology Group, University of Groningen, Groningen, The Netherlands.,IMIBIO-SL CONICET, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
| | - Maximiliano Juri Ayub
- IMIBIO-SL CONICET, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Groningen, The Netherlands
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Li S, Sun K, Yan X, Lu C, Waigi MG, Liu J, Ling W. Identification of novel catabolic genes involved in 17β-estradiol degradation by Novosphingobium sp. ES2-1. Environ Microbiol 2021; 23:2550-2563. [PMID: 33754450 DOI: 10.1111/1462-2920.15475] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 03/18/2021] [Indexed: 12/17/2022]
Abstract
Novosphingobium sp. ES2-1 is an efficient 17β-estradiol (E2)-degrading bacterium, which can convert E2 to estrone (E1), then to 4-hydroxyestrone (4-OH-E1) for subsequent oxidative cracking. In this study, the molecular bases for this process were elucidated. Two novel monooxygenase systems EstP and EstO were shown to catalyse the oxygenation of E1 and 4-OH-E1, respectively. EstP was a three-component cytochrome P450 monooxygenase system consisting of EstP1 (P450 monooxygenase), EstP2 (ferredoxin) and EstP3 (ferredoxin reductase). Ultraperformance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) analysis revealed that EstP catalysed the 4-hydroxylation of E1 to produce 4-OH-E1. The resultant 4-OH-E1 was further oxidized by a two-component monooxygenase system EstO consisting of EstO1 (flavin-dependent monooxygenases) and EstO2 (flavin reductase). UPLC-HRMS combined with 1 H-nuclear magnetic resonance analysis demonstrated that EstO catalysed the breakage of C9-C10 to yield a ring B-cleavage product. In addition, the oxygenase component genes estP1 and estO1 exhibited contrary inductive behaviours when exposed to different steroids, suggesting that EstP1-mediated 4-hydroxylation was E2-specific, whereas EstO1-mediated monooxygenation might be involved in the degradation of testosterone, androstenedione, progesterone and pregnenolone. This also implied that the mechanisms of the catabolism of different steroids by the same microorganism might be partially interlinked.
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Affiliation(s)
- Shunyao Li
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Kai Sun
- Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Chao Lu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Michael Gatheru Waigi
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Juan Liu
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wanting Ling
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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Wolf J, Koblitz J, Albersmeier A, Kalinowski J, Siebers B, Schomburg D, Neumann-Schaal M. Utilization of Phenol as Carbon Source by the Thermoacidophilic Archaeon Saccharolobus solfataricus P2 Is Limited by Oxygen Supply and the Cellular Stress Response. Front Microbiol 2021; 11:587032. [PMID: 33488537 PMCID: PMC7820114 DOI: 10.3389/fmicb.2020.587032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 12/08/2020] [Indexed: 12/20/2022] Open
Abstract
Present in many industrial effluents and as common degradation product of organic matter, phenol is a widespread compound which may cause serious environmental problems, due to its toxicity to animals and humans. Degradation of phenol from the environment by mesophilic bacteria has been studied extensively over the past decades, but only little is known about phenol biodegradation at high temperatures or low pH. In this work we studied phenol degradation in the thermoacidophilic archaeon Saccharolobus solfataricus P2 (basonym: Sulfolobus solfataricus) under extreme conditions (80°C, pH 3.5). We combined metabolomics and transcriptomics together with metabolic modeling to elucidate the organism’s response to growth with phenol as sole carbon source. Although S. solfataricus is able to utilize phenol for biomass production, the carbon source induces profound stress reactions, including genome rearrangement as well as a strong intracellular accumulation of polyamines. Furthermore, computational modeling revealed a 40% higher oxygen demand for substrate oxidation, compared to growth on glucose. However, only 16.5% of oxygen is used for oxidation of phenol to catechol, resulting in a less efficient integration of carbon into the biomass. Finally, our data underlines the importance of the phenol meta-degradation pathway in S. solfataricus and enables us to predict enzyme candidates involved in the degradation processes downstream of 2-hydroxymucconic acid.
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Affiliation(s)
- Jacqueline Wolf
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Julia Koblitz
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Braunschweig, Germany
| | | | - Jörn Kalinowski
- Center for Biotechnology-CeBiTec, Universität Bielefeld, Bielefeld, Germany
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry (MEB), Environmental Microbiology and Biotechnology (EMB), Centre for Water and Environmental Research (CWE), University of Duisburg-Essen, Essen, Germany
| | - Dietmar Schomburg
- Department of Bioinformatics and Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Braunschweig, Germany
| | - Meina Neumann-Schaal
- Braunschweig Integrated Centre of Systems Biology (BRICS), Braunschweig, Germany.,Junior Research Group Bacterial Metabolomics, Leibniz Institute DSMZ German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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9
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Min J, Xu L, Fang S, Chen W, Hu X. Microbial degradation kinetics and molecular mechanism of 2,6-dichloro-4-nitrophenol by a Cupriavidus strain. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113703. [PMID: 31818627 DOI: 10.1016/j.envpol.2019.113703] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/03/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
2,6-Dichloro-4-nitrophenol (2,6-DCNP) is an emerging chlorinated nitroaromatic pollutant, and its fate in the environment is an important question. However, microorganisms with the ability to utilize 2,6-DCNP have not been reported. In this study, Cupriavidus sp. CNP-8 having been previously reported to degrade various halogenated nitrophenols, was verified to be also capable of degrading 2,6-DCNP. Biodegradation kinetics assay showed that it degraded 2,6-DCNP with the specific growth rate of 0.124 h-1, half saturation constant of 0.038 mM and inhibition constant of 0.42 mM. Real-time quantitative PCR analyses indicated that the hnp gene cluster was involved in the catabolism of 2,6-DCNP. The hnpA and hnpB gene products were purified to homogeneity by Ni-NTA chromatography. Enzymatic assays showed that HnpAB, a FAD-dependent two-component monooxygenase, converted 2,6-DCNP to 6-chlorohydroxyquinol with a Km of 3.9 ± 1.4 μM and a kcat/Km of 0.12 ± 0.04 μΜ-1 min-1. As the oxygenase component encoding gene, hnpA is necessary for CNP-8 to grow on 2,6-DCNP by gene knockout and complementation. The phylogenetic analysis showed that the hnp cluster originated from the cluster involved in the catabolism of chlorophenols rather than nitrophenols. To our knowledge, CNP-8 is the first bacterium with the ability to utilize 2,6-DCNP, and this study fills a gap in the microbial degradation mechanism of this pollutant at the molecular, biochemical and genetic levels. Moreover, strain CNP-8 could degrade three chlorinated nitrophenols rapidly from the synthetic wastewater, indicating its potential in the bioremediation of chlorinated nitrophenols polluted environments.
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Affiliation(s)
- Jun Min
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Lingxue Xu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; College of Life Science of Yantai University, Yantai, China
| | - Suyun Fang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Weiwei Chen
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiaoke Hu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
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Christova N, Kabaivanova L, Nacheva L, Petrov P, Stoineva I. Biodegradation of crude oil hydrocarbons by a newly isolated biosurfactant producing strain. BIOTECHNOL BIOTEC EQ 2019. [DOI: 10.1080/13102818.2019.1625725] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Nelly Christova
- Department of Applied Microbiology The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Lyudmila Kabaivanova
- Department of Applied Microbiology The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Lilyana Nacheva
- Department of Applied Microbiology The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Petar Petrov
- Laboratory of Functional and Nanostryctured Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Ivanka Stoineva
- Laboratory of Chemistry and Biophysics of Proteins and Enzymes, Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria
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Heine T, van Berkel WJH, Gassner G, van Pée KH, Tischler D. Two-Component FAD-Dependent Monooxygenases: Current Knowledge and Biotechnological Opportunities. BIOLOGY 2018; 7:biology7030042. [PMID: 30072664 PMCID: PMC6165268 DOI: 10.3390/biology7030042] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/11/2022]
Abstract
Flavoprotein monooxygenases create valuable compounds that are of high interest for the chemical, pharmaceutical, and agrochemical industries, among others. Monooxygenases that use flavin as cofactor are either single- or two-component systems. Here we summarize the current knowledge about two-component flavin adenine dinucleotide (FAD)-dependent monooxygenases and describe their biotechnological relevance. Two-component FAD-dependent monooxygenases catalyze hydroxylation, epoxidation, and halogenation reactions and are physiologically involved in amino acid metabolism, mineralization of aromatic compounds, and biosynthesis of secondary metabolites. The monooxygenase component of these enzymes is strictly dependent on reduced FAD, which is supplied by the reductase component. More and more representatives of two-component FAD-dependent monooxygenases have been discovered and characterized in recent years, which has resulted in the identification of novel physiological roles, functional properties, and a variety of biocatalytic opportunities.
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Affiliation(s)
- Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - George Gassner
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
| | - Karl-Heinz van Pée
- Allgemeine Biochemie, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
- Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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12
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Hydrolase CehA and Monooxygenase CfdC Are Responsible for Carbofuran Degradation in Sphingomonas sp. Strain CDS-1. Appl Environ Microbiol 2018; 84:AEM.00805-18. [PMID: 29884759 DOI: 10.1128/aem.00805-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/31/2018] [Indexed: 01/29/2023] Open
Abstract
Carbofuran, a broad-spectrum systemic insecticide, has been extensively used for approximately 50 years. Diverse carbofuran-degrading bacteria have been described, among which sphingomonads have exhibited an extraordinary ability to catabolize carbofuran; other bacteria can only convert carbofuran to carbofuran phenol, while all carbofuran-degrading sphingomonads can degrade both carbofuran and carbofuran phenol. However, the genetic basis of carbofuran catabolism in sphingomonads has not been well elucidated. In this work, we sequenced the draft genome of Sphingomonas sp. strain CDS-1 that can transform both carbofuran and carbofuran phenol but fails to grow on them. On the basis of the hypothesis that the genes involved in carbofuran catabolism are highly conserved among carbofuran-degrading sphingomonads, two such genes, cehACDS-1 and cfdCCDS-1, were predicted from the 84 open reading frames (ORFs) that share ≥95% nucleic acid similarities between strain CDS-1 and another sphingomonad Novosphingobium sp. strain KN65.2 that is able to mineralize the benzene ring of carbofuran. The results of the gene knockout, genetic complementation, heterologous expression, and enzymatic experiments reveal that cehACDS-1 and cfdCCDS-1 are responsible for the conversion of carbofuran and carbofuran phenol, respectively, in strain CDS-1. CehACDS-1 hydrolyzes carbofuran to carbofuran phenol. CfdCCDS-1, a reduced flavin mononucleotide (FMNH2)- or reduced flavin adenine dinucleotide (FADH2)-dependent monooxygenase, hydroxylates carbofuran phenol at the benzene ring in the presence of NADH, FMN/FAD, and the reductase CfdX. It is worth noting that we found that carbaryl hydrolase CehAAC100, which was previously demonstrated to have no activity toward carbofuran, can actually convert carbofuran to carbofuran phenol, albeit with very low activity.IMPORTANCE Due to the extensive use of carbofuran over the past 50 years, bacteria have evolved catabolic pathways to mineralize this insecticide, which plays an important role in eliminating carbofuran residue in the environment. This study revealed the genetic determinants of carbofuran degradation in Sphingomonas sp. strain CDS-1. We speculate that the close homologues cehA and cfdC are highly conserved among other carbofuran-degrading sphingomonads and play the same roles as those described here. These findings deepen our understanding of the microbial degradation mechanism of carbofuran and lay a foundation for the better use of microbes to remediate carbofuran contamination.
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Singh DP, Prabha R, Gupta VK, Verma MK. Metatranscriptome Analysis Deciphers Multifunctional Genes and Enzymes Linked With the Degradation of Aromatic Compounds and Pesticides in the Wheat Rhizosphere. Front Microbiol 2018; 9:1331. [PMID: 30034370 PMCID: PMC6043799 DOI: 10.3389/fmicb.2018.01331] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 05/31/2018] [Indexed: 11/19/2022] Open
Abstract
Agricultural soils are becoming contaminated with synthetic chemicals like polyaromatic compounds, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), phenols, herbicides, insecticides and fungicides due to excessive dependency of crop production systems on the chemical inputs. Microbial degradation of organic pollutants in the agricultural soils is a continuous process due to the metabolic multifunctionalities and enzymatic capabilities of the soil associated communities. The plant rhizosphere with its complex microbial inhabitants and their multiple functions, is amongst the most live and dynamic component of agricultural soils. We analyzed the metatranscriptome data of 20 wheat rhizosphere samples to decipher the taxonomic microbial communities and their multifunctionalities linked with the degradation of organic soil contaminants. The analysis revealed a total of 21 different metabolic pathways for the degradation of aromatic compounds and 06 for the xenobiotics degradation. Taxonomic annotation of wheat rhizosphere revealed bacteria, especially the Proteobacteria, actinobacteria, firmicutes, bacteroidetes, and cyanobacteria, which are shown to be linked with the degradation of aromatic compounds as the dominant communities. Abundance of the transcripts related to the degradation of aromatic amin compounds, carbazoles, benzoates, naphthalene, ketoadipate pathway, phenols, biphenyls and xenobiotics indicated abundant degradation capabilities in the soils. The results highlighted a potentially dominant role of crop rhizosphere associated microbial communities in the remediation of contaminant aromatic compounds.
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Affiliation(s)
- Dhananjaya P. Singh
- ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, India
| | - Ratna Prabha
- Department of Bio-Medical Engineering and Bio-Informatics, Chhattisgarh Swami Vivekanand Technical University, Bhilai, India
| | - Vijai K. Gupta
- ERA Chair of Green Chemistry, Department of Chemistry and Biotechnology, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Mukesh K. Verma
- Department of Bio-Medical Engineering and Bio-Informatics, Chhattisgarh Swami Vivekanand Technical University, Bhilai, India
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A benzene-degrading nitrate-reducing microbial consortium displays aerobic and anaerobic benzene degradation pathways. Sci Rep 2018. [PMID: 29540736 PMCID: PMC5852087 DOI: 10.1038/s41598-018-22617-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this study, we report transcription of genes involved in aerobic and anaerobic benzene degradation pathways in a benzene-degrading denitrifying continuous culture. Transcripts associated with the family Peptococcaceae dominated all samples (21-36% relative abundance) indicating their key role in the community. We found a highly transcribed gene cluster encoding a presumed anaerobic benzene carboxylase (AbcA and AbcD) and a benzoate-coenzyme A ligase (BzlA). Predicted gene products showed >96% amino acid identity and similar gene order to the corresponding benzene degradation gene cluster described previously, providing further evidence for anaerobic benzene activation via carboxylation. For subsequent benzoyl-CoA dearomatization, bam-like genes analogous to the ones found in other strict anaerobes were transcribed, whereas gene transcripts involved in downstream benzoyl-CoA degradation were mostly analogous to the ones described in facultative anaerobes. The concurrent transcription of genes encoding enzymes involved in oxygenase-mediated aerobic benzene degradation suggested oxygen presence in the culture, possibly formed via a recently identified nitric oxide dismutase (Nod). Although we were unable to detect transcription of Nod-encoding genes, addition of nitrite and formate to the continuous culture showed indication for oxygen production. Such an oxygen production would enable aerobic microbes to thrive in oxygen-depleted and nitrate-containing subsurface environments contaminated with hydrocarbons.
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15
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Wang Y, Zhao C, Zhang D, Zhao M, Zheng D, Lyu Y, Cheng W, Guo P, Cui Z. Effective degradation of aflatoxin B 1 using a novel thermophilic microbial consortium TADC7. BIORESOURCE TECHNOLOGY 2017; 224:166-173. [PMID: 27866802 DOI: 10.1016/j.biortech.2016.11.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/06/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
We constructed a novel thermophilic microbial consortium, TADC7, with stable and efficient aflatoxin B1 (AFB1) degradation activity. The microbial consortium degraded more than 95% of the toxin within 72h when cultured with AFB1, and the optimum temperature was 55-60°C. TADC7 tolerated high doses of AFB1, with no inhibitory effects up to 5000μgL-1 AFB1; moreover, the degradation kinetics fit well with the Monod model. The proteins or enzymes in the TADC7 cell-free supernatant played a major role in AFB1 degradation. AFB1 degradation by the cell-free supernatant was stable up to 90°C, with an optimal pH of 8-10. We performed 16S rRNA sequencing to determine TADC7 community structure dynamics; the results indicated that Geobacillus and Tepidimicrobium played major roles in AFB1 degradation.
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Affiliation(s)
- Yi Wang
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; College of Biology and Pharmacy, Three Gorges University, Yichang 443002, China
| | - Chunxia Zhao
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; College of Biology and Pharmacy, Three Gorges University, Yichang 443002, China
| | - Dongdong Zhang
- Institute of Marine Biology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Mingming Zhao
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Dan Zheng
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Yucai Lyu
- College of Biology and Pharmacy, Three Gorges University, Yichang 443002, China
| | - Wei Cheng
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Peng Guo
- Institute of Agricultural Products Processing and Nuclear Agriculture Technology Research, Hubei Academy of Agricultural Sciences, Wuhan 430064, China.
| | - Zongjun Cui
- College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
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16
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Kynadi AS, Suchithra TV. Bacterial Degradation of Phenol to Control Environmental Pollution. Microb Biotechnol 2017. [DOI: 10.1007/978-981-10-6847-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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17
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Zhang P, Jia R, Zhang Y, Shi P, Chai T. Quinoline-degrading strain Pseudomonas aeruginosa KDQ4 isolated from coking activated sludge is capable of the simultaneous removal of phenol in a dual substrate system. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2016; 51:1139-1148. [PMID: 27458688 DOI: 10.1080/10934529.2016.1206377] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quinoline is a refractory organic compound in the treatment of coking wastewater. The isolation of high efficiency quinoline-degrading bacteria from activated sludge and the evaluation of their degradation characteristics in the presence of phenol or in the actual coking wastewater are important for the improvement of effluent quality. The novel bacterial strain Pseudomonas aeruginosa KDQ4 was isolated from a quinoline enrichment culture obtained from the activated sludge of a coking wastewater treatment plant. The optimum temperature and initial pH for quinoline degradation were 33-38°C and 8-9, respectively. KDQ4 completely degraded 400 mg/L of quinoline within 24 h and 800 mg/L of phenol within 30 h. In the dual-substrate system, the removal efficiencies of quinoline and phenol at the same initial concentration (200 mg/L) by KDQ4 were 89% and 100% within 24 h, respectively, indicating that KDQ4 could simultaneously and quickly degrade quinoline and phenol in a coexistence system. Moreover, KDQ4 was able to adapt to actual coking wastewater containing high quinoline and phenol concentrations and rapidly remove them. KDQ4 also exhibited heterotrophic nitrification and aerobic denitrification potential under aerobic conditions. These results suggested a potential bioaugmentation role for KDQ4 in the removal of nitrogen-heterocyclic compounds and phenolics from coking wastewater.
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Affiliation(s)
- Panhong Zhang
- a State Key Laboratory of Environmental Chemistry and Ecotoxicity , Research center for Eco-Environment of Sciences, Chinese Academy of Sciences , Beijing , PR China
- b Sino-Danish Center for Education and Research , Chinese Academy of Sciences , Beijing , PR China
| | - Rong Jia
- c Department of Environmental & Biological Engineering , School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing) , Beijing , PR China
| | - Yuxiu Zhang
- c Department of Environmental & Biological Engineering , School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing) , Beijing , PR China
| | - Peili Shi
- c Department of Environmental & Biological Engineering , School of Chemical & Environmental Engineering, China University of Mining & Technology (Beijing) , Beijing , PR China
| | - Tuanyao Chai
- d College of Life Science , University of Chinese Academy of Sciences , Beijing , PR China
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18
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Nešvera J, Rucká L, Pátek M. Catabolism of Phenol and Its Derivatives in Bacteria: Genes, Their Regulation, and Use in the Biodegradation of Toxic Pollutants. ADVANCES IN APPLIED MICROBIOLOGY 2015; 93:107-60. [PMID: 26505690 DOI: 10.1016/bs.aambs.2015.06.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Phenol and its derivatives (alkylphenols, halogenated phenols, nitrophenols) are natural or man-made aromatic compounds that are ubiquitous in nature and in human-polluted environments. Many of these substances are toxic and/or suspected of mutagenic, carcinogenic, and teratogenic effects. Bioremediation of the polluted soil and water using various bacteria has proved to be a promising option for the removal of these compounds. In this review, we describe a number of peripheral pathways of aerobic and anaerobic catabolism of various natural and xenobiotic phenolic compounds, which funnel these substances into a smaller number of central catabolic pathways. Finally, the metabolites are used as carbon and energy sources in the citric acid cycle. We provide here the characteristics of the enzymes that convert the phenolic compounds and their catabolites, show their genes, and describe regulatory features. The genes, which encode these enzymes, are organized on chromosomes and plasmids of the natural bacterial degraders in various patterns. The accumulated data on similarities and the differences of the genes, their varied organization, and particularly, an astonishingly broad range of intricate regulatory mechanism may be read as an exciting adventurous book on divergent evolutionary processes and horizontal gene transfer events inscribed in the bacterial genomes. In the end, the use of this wealth of bacterial biodegradation potential and the manipulation of its genetic basis for purposes of bioremediation is exemplified. It is envisioned that the integrated high-throughput techniques and genome-level approaches will enable us to manipulate systems rather than separated genes, which will give birth to systems biotechnology.
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Affiliation(s)
- Jan Nešvera
- Institute of Microbiology CAS, v. v. i., Prague, Czech Republic
| | - Lenka Rucká
- Institute of Microbiology CAS, v. v. i., Prague, Czech Republic
| | - Miroslav Pátek
- Institute of Microbiology CAS, v. v. i., Prague, Czech Republic
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19
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Holtmann D, Fraaije MW, Arends IWCE, Opperman DJ, Hollmann F. The taming of oxygen: biocatalytic oxyfunctionalisations. Chem Commun (Camb) 2015; 50:13180-200. [PMID: 24902635 DOI: 10.1039/c3cc49747j] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The scope and limitations of oxygenases as catalysts for preparative organic synthesis is discussed.
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Affiliation(s)
- Dirk Holtmann
- DECHEMA Research Institute, Theodor-Heuss-Allee 25, 60486 Frankfurt am Main, Germany
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20
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Abstract
The genus Geobacillus comprises a group of Gram-positive thermophilic bacteria, including obligate aerobes, denitrifiers, and facultative anaerobes that can grow over a range of 45-75°C. Originally classified as group five Bacillus spp., strains of Bacillus stearothermophilus came to prominence as contaminants of canned food and soon became the organism of choice for comparative studies of metabolism and enzymology between mesophiles and thermophiles. More recently, their catabolic versatility, particularly in the degradation of hemicellulose and starch, and rapid growth rates have raised their profile as organisms with potential for second-generation (lignocellulosic) biorefineries for biofuel or chemical production. The continued development of genetic tools to facilitate both fundamental investigation and metabolic engineering is now helping to realize this potential, for both metabolite production and optimized catabolism. In addition, this catabolic versatility provides a range of useful thermostable enzymes for industrial application. A number of genome-sequencing projects have been completed or are underway allowing comparative studies. These reveal a significant amount of genome rearrangement within the genus, the presence of large genomic islands encompassing all the hemicellulose utilization genes and a genomic island incorporating a set of long chain alkane monooxygenase genes. With G+C contents of 45-55%, thermostability appears to derive in part from the ability to synthesize protamine and spermine, which can condense DNA and raise its Tm.
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21
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Gröning JAD, Eulberg D, Tischler D, Kaschabek SR, Schlömann M. Gene redundancy of two-component (chloro)phenol hydroxylases in Rhodococcus opacus 1CP. FEMS Microbiol Lett 2015; 361:68-75. [PMID: 25283988 DOI: 10.1111/1574-6968.12616] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/27/2014] [Accepted: 09/29/2014] [Indexed: 11/29/2022] Open
Abstract
Among other factors, a distinct gene redundancy is discussed to facilitate high metabolic versatility of rhodococci. Rhodococcus opacus 1CP is a typical member in that respect and degrades a multitude of (chlorinated) aromatic compounds. In contrast to the central pathways of aromatic degradation in strain 1CP, little is known about the degree of gene redundancy and to what extent this is reflected on protein level within the steps of peripheral degradation. By means of degenerated primers deduced from tryptic peptides of a purified phenol hydroxylase component and using the amplified fragment as a labelled probe against genomic 1CP-DNA, three gene sets encoding three different two-component phenol hydroxylases pheA1/pheA2(1-3) could be identified. One of them was found to be located on the megaplasmid p1CP, which confirms the role of these elements for metabolic versatility. Protein chromatography of phenol- and 4-chlorophenol-grown 1CP-biomass gave first evidences on a functional expression of these oxygenases, which could be initially characterised in respect of their substrate specificity.
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Affiliation(s)
- Janosch A D Gröning
- Environmental Microbiology, IÖZ, TU Bergakademie Freiberg, Freiberg, Germany
| | | | - Dirk Tischler
- Environmental Microbiology, IÖZ, TU Bergakademie Freiberg, Freiberg, Germany
| | - Stefan R Kaschabek
- Environmental Microbiology, IÖZ, TU Bergakademie Freiberg, Freiberg, Germany
| | - Michael Schlömann
- Environmental Microbiology, IÖZ, TU Bergakademie Freiberg, Freiberg, Germany
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22
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Activity of a carboxyl-terminal truncated form of catechol 2,3-dioxygenase from Planococcus sp. S5. ScientificWorldJournal 2014; 2014:598518. [PMID: 24693238 PMCID: PMC3943285 DOI: 10.1155/2014/598518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/26/2013] [Indexed: 11/17/2022] Open
Abstract
Catechol 2,3-dioxygenases (C23Os, E.C.1.13.12.2) are two domain enzymes that catalyze degradation of monoaromatic hydrocarbons. The catalytically active C-domain of all known C23Os comprises ferrous ion ligands as well as residues forming active site pocket. The aim of this work was to examine and discuss the effect of nonsense mutation at position 289 on the activity of catechol 2,3-dioxygenase from Planococcus strain. Although the mutant C23O showed the same optimal temperature for activity as the wild-type protein (35°C), it exhibited activity slightly more tolerant to alkaline pH. Mutant enzyme exhibited also higher affinity to catechol as a substrate. Its Km (66.17 µM) was approximately 30% lower than that of wild-type enzyme. Interestingly, removal of the C-terminal residues resulted in 1.5- to 1.8-fold (P < 0.05) increase in the activity of C23OB61 against 4-methylcatechol and 4-chlorocatechol, respectively, while towards catechol the activity of the protein dropped to about 80% of that of the wild-type enzyme. The results obtained may facilitate the engineering of the C23O for application in the bioremediation of polluted areas.
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23
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Uchiyama T, Miyazaki K. Metagenomic screening for aromatic compound-responsive transcriptional regulators. PLoS One 2013; 8:e75795. [PMID: 24098725 PMCID: PMC3786939 DOI: 10.1371/journal.pone.0075795] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 08/21/2013] [Indexed: 11/18/2022] Open
Abstract
We applied a metagenomics approach to screen for transcriptional regulators that sense aromatic compounds. The library was constructed by cloning environmental DNA fragments into a promoter-less vector containing green fluorescence protein. Fluorescence-based screening was then performed in the presence of various aromatic compounds. A total of 12 clones were isolated that fluoresced in response to salicylate, 3-methyl catechol, 4-chlorocatechol and chlorohydroquinone. Sequence analysis revealed at least 1 putative transcriptional regulator, excluding 1 clone (CHLO8F). Deletion analysis identified compound-specific transcriptional regulators; namely, 8 LysR-types, 2 two-component-types and 1 AraC-type. Of these, 9 representative clones were selected and their reaction specificities to 18 aromatic compounds were investigated. Overall, our transcriptional regulators were functionally diverse in terms of both specificity and induction rates. LysR- and AraC- type regulators had relatively narrow specificities with high induction rates (5-50 fold), whereas two-component-types had wide specificities with low induction rates (3 fold). Numerous transcriptional regulators have been deposited in sequence databases, but their functions remain largely unknown. Thus, our results add valuable information regarding the sequence–function relationship of transcriptional regulators.
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Affiliation(s)
- Taku Uchiyama
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Kentaro Miyazaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Hokkaido, Japan
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Hokkaido, Japan
- * E-mail:
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24
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Sokolova A, Huang SL, Duff A, Gilbert EP, Li WH. Correlation of thermostability and conformational changes of catechol 2, 3-dioxygenases from two disparate micro-organisms. Biophys Chem 2013; 180-181:145-52. [PMID: 23994541 DOI: 10.1016/j.bpc.2013.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 07/21/2013] [Accepted: 07/22/2013] [Indexed: 11/26/2022]
Abstract
We have investigated the structure of recombinant catechol 2, 3-dioxygenase (C23O) purified from two species in which the enzyme has evolved to function at different temperature. The two species are mesophilic bacterium Pseudomonas putida strain mt-2 and thermophilic archaea Sulfolobus acidocaldariusDSM639. Using the primary sequence analysis, we show that both C23Os have only 30% identity and 48% similarity but contain conserved amino acid residues forming an active site area around the iron ion. The corresponding differences in homology, but structural similarity in active area residues, appear to provide completely different responses to heating the two enzymes. We confirm this by small angle X-ray scattering and demonstrate that the overall structure of C23O from P. putida is slightly different from its crystalline form whereas the solution scattering of C23O from S. acidocaldarius at temperatures between 4 and 85°C ideally fits the calculated scattering from the single crystal structure. The thermostability of C23O from S. acidocaldarius correlates well with conformation in solution during thermal treatment. The similarity of the two enzymes in primary and tertiary structure may be taken as a confirmation that two enzymes have evolved from a common ancestor.
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Affiliation(s)
- Anna Sokolova
- Bragg Institute, ANSTO, Locked Bag 2001, Kirrawee DC, NSW, 2232 Australia.
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25
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Orenes-Piñero E, García-Carmona F, Sánchez-Ferrer Á. A new process for obtaining hydroxytyrosol using transformed Escherichia coli whole cells with phenol hydroxylase gene from Geobacillus thermoglucosidasius. Food Chem 2013; 139:377-83. [DOI: 10.1016/j.foodchem.2012.12.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 12/12/2012] [Accepted: 12/19/2012] [Indexed: 11/24/2022]
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26
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Taylor MP, Mulako I, Tuffin M, Cowan D. Understanding physiological responses to pre-treatment inhibitors in ethanologenic fermentations. Biotechnol J 2012; 7:1169-81. [PMID: 22331581 DOI: 10.1002/biot.201100335] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 12/15/2011] [Accepted: 01/17/2012] [Indexed: 11/10/2022]
Abstract
Alcohol-based liquid fuels feature significantly in the political and social agendas of many countries, seeking energy sustainability. It is certain that ethanol will be the entry point for many sustainable processes. Conventional ethanol production using maize- and sugarcane-based carbohydrates with Saccharomyces cerevisiae is well established, while lignocellulose-based processes are receiving growing interest despite posing greater technical and scientific challenges. A significant challenge that arises from the chemical hydrolysis of lignocellulose is the generation of toxic compounds in parallel with the release of sugars. These compounds, collectively termed pre-treatment inhibitors, impair metabolic functionality and growth. Their removal, pre-fermentation or their abatement, via milder hydrolysis, are currently uneconomic options. It is widely acknowledged that a more cost effective strategy is to develop resistant process strains. Here we describe and classify common inhibitors and describe in detail the reported physiological responses that occur in second-generation strains, which include engineered yeast and mesophilic and thermophilic prokaryotes. It is suggested that a thorough understanding of tolerance to common pre-treatment inhibitors should be a major focus in ongoing strain engineering. This review is a useful resource for future metabolic engineering strategies.
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Affiliation(s)
- Mark P Taylor
- TMO Renewables Ltd., The Surrey Research Park, Guildford, UK
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27
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28
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Moreno MDL, Sánchez-Porro C, Piubeli F, Frias L, García MT, Mellado E. Cloning, characterization and analysis of cat and ben genes from the phenol degrading halophilic bacterium Halomonas organivorans. PLoS One 2011; 6:e21049. [PMID: 21695219 PMCID: PMC3112211 DOI: 10.1371/journal.pone.0021049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 05/18/2011] [Indexed: 11/28/2022] Open
Abstract
Background Extensive use of phenolic compounds in industry has resulted in the generation of saline wastewaters that produce significant environmental contamination; however, little information is available on the degradation of phenolic compounds in saline conditions. Halomonas organivorans G-16.1 (CECT 5995T) is a moderately halophilic bacterium that we isolated in a previous work from saline environments of South Spain by enrichment for growth in different pollutants, including phenolic compounds. PCR amplification with degenerate primers revealed the presence of genes encoding ring-cleaving enzymes of the β-ketoadipate pathway for aromatic catabolism in H. organivorans. Findings The gene cluster catRBCA, involved in catechol degradation, was isolated from H. organivorans. The genes catA, catB, catC and the divergently transcribed catR code for catechol 1,2-dioxygenase (1,2-CTD), cis,cis-muconate cycloisomerase, muconolactone delta-isomerase and a LysR-type transcriptional regulator, respectively. The benzoate catabolic genes (benA and benB) are located flanking the cat genes. The expression of cat and ben genes by phenol and benzoic acid was shown by RT-PCR analysis. The induction of catA gene by phenol and benzoic acid was also probed by the measurement of 1,2-CTD activity in H. organivorans growth in presence of these inducers. 16S rRNA and catA gene-based phylogenies were established among different degrading bacteria showing no phylogenetic correlation between both genes. Conclusions/Significance In this work, we isolated and determined the sequence of a gene cluster from a moderately halophilic bacterium encoding ortho-pathway genes involved in the catabolic metabolism of phenol and analyzed the gene organization, constituting the first report characterizing catabolic genes involved in the degradation of phenol in moderate halophiles, providing an ideal model system to investigate the potential use of this group of extremophiles in the decontamination of saline environments.
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Affiliation(s)
| | | | - Francine Piubeli
- Department of Food Science, University of Campinas, Sao Paulo, Brazil
| | - Luciana Frias
- Department of Food Science, University of Campinas, Sao Paulo, Brazil
| | - María Teresa García
- Department of Microbiology and Parasitology, University of Sevilla, Sevilla, Spain
| | - Encarnación Mellado
- Department of Microbiology and Parasitology, University of Sevilla, Sevilla, Spain
- * E-mail:
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29
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Yu H, Peng Z, Zhan Y, Wang J, Yan Y, Chen M, Lu W, Ping S, Zhang W, Zhao Z, Li S, Takeo M, Lin M. Novel regulator MphX represses activation of phenol hydroxylase genes caused by a XylR/DmpR-type regulator MphR in Acinetobacter calcoaceticus. PLoS One 2011; 6:e17350. [PMID: 21455294 PMCID: PMC3063778 DOI: 10.1371/journal.pone.0017350] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/31/2011] [Indexed: 11/18/2022] Open
Abstract
Acinetobacter calcoaceticus PHEA-2 utilizes phenol as its sole carbon and energy source and has a multi-component phenol hydroxylase-encoding gene operon (mphKLMNOP) for phenol degradation. Two additional genes, mphR and mphX, were found upstream and downstream of mphKLMNOP, respectively. The mphR gene encodes a XylR/DmpR-type regulator-like protein and is transcribed in the opposite direction to mphKLMNOP. The mphX gene is transcribed in the same direction as mphKLMNOP and encodes a protein with 293 amino acid residues showing weak identity with some unknown proteins encoded in the meta-cleavage pathway gene clusters for aromatic compound degradation. Disruption of mphR by homologous recombination resulted in the loss of phenol degradation while disruption of mphX caused significantly faster phenol degradation than in the wild type strain. Transcriptional assays for mphK, mphR, and mphX revealed that mphR activated mphKLMNOP transcription in the presence of phenol, but mphX partially repressed this activation. Gel mobility-shift assay demonstrated a direct interaction of MphR with the mphK promoter region. These results indicate the involvement of a novel repressor protein MphX in transcriptional regulation of phenol hydroxylase genes caused by a XylR/DmpR-type regulator MphR.
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Affiliation(s)
- Haiying Yu
- College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Zixin Peng
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Hyogo, Japan
| | - Yuhua Zhan
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Jin Wang
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Yongliang Yan
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
- National Centre for Plant Gene Research, Beijing, China
| | - Ming Chen
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Wei Lu
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Shuzhen Ping
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Wei Zhang
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
- National Centre for Plant Gene Research, Beijing, China
| | - Zhonglin Zhao
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Shuying Li
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
| | - Masahiro Takeo
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji, Hyogo, Japan
- * E-mail: (MT); (ML)
| | - Min Lin
- College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Crop Biotechnology, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, Beijing, China
- * E-mail: (MT); (ML)
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Yamamoto K, Nishimura M, Kato DI, Takeo M, Negoro S. Identification and characterization of another 4-nitrophenol degradation gene cluster, nps, in Rhodococcus sp. strain PN1. J Biosci Bioeng 2011; 111:687-94. [PMID: 21396889 DOI: 10.1016/j.jbiosc.2011.01.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/13/2011] [Accepted: 01/28/2011] [Indexed: 11/15/2022]
Abstract
4-Nitrophenol (4-NP) is a toxic compound formed in soil by the hydrolysis of organophosphorous pesticides, such as parathion. We previously reported the presence of the 4-NP degradation gene cluster (nphRA1A2) in Rhodococcus sp. strain PN1, which encodes a two-component 4-NP hydroxylase system that oxidizes 4-NP into 4-nitrocatechol. In the current study, another gene cluster (npsC and npsRA2A1B) encoding a similar 4-NP hydroxylase system was cloned from strain PN1. The enzymes from this 4-NP hydroxylase system (NpsA1 and NpsA2) were purified as histidine-tagged (His-) proteins and then characterized. His-NpsA2 showed NADH/FAD oxidoreductase activity, and His-NpsA1 showed 4-NP oxidizing activity in the presence of His-NpsA2. In the 4-NP oxidation using the reconstituted enzyme system (His-NpsA1 and His-NpsA2), hydroquinone (35% of 4-NP disappeared) and hydroxyquinol (59% of 4-NP disappeared) were detected in the presence of ascorbic acid as a reducing reagent, suggesting that, without the reducing reagent, 4-NP was converted into their oxidized forms, 1,4-benzoquinone and 2-hydroxy-1,4-benzoquinone. In addition, in the cell extract of recombinant Escherichia coli expressing npsB, a typical spectral change showing conversion of hydroxyquinol into maleylacetate was observed. These results indicate that this nps gene cluster, in addition to the nph gene cluster, is also involved in 4-NP degradation in strain PN1.
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Affiliation(s)
- Kenta Yamamoto
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
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Arcos M, Olivera ER, Arias S, Naharro G, Luengo JM. The 3,4-dihydroxyphenylacetic acid catabolon, a catabolic unit for degradation of biogenic amines tyramine and dopamine in Pseudomonas putida U. Environ Microbiol 2010; 12:1684-704. [PMID: 20482587 DOI: 10.1111/j.1462-2920.2010.02233.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Degradation of tyramine and dopamine by Pseudomonas putida U involves the participation of twenty one proteins organized in two coupled catabolic pathways, Tyn (tynABFEC tynG tynR tynD, 12 338 bp) and Hpa (hpaR hpaBC hpaHI hpaX hpaG1G2EDF hpaA hpaY, 12 722 bp). The Tyn pathway catalyses the conversion of tyramine and dopamine into 4-hydroxyphenylacetic acid (4HPA) and 3,4-dihydroxyphenylacetic acid (3,4HPA) respectively. Together, the Tyn and Hpa pathways constitute a complex catabolic unit (the 3,4HPA catabolon) in which 3,4HPA is the central intermediate. The genes encoding Tyn proteins are organized in four consecutive transcriptional units (tynABFEC, tynG, tynR and tynD), whereas those encoding Hpa proteins constitute consecutive operons (hpaBC, hpaG1G2EDF, hpaX, hpaHI) and three independent units (hpaA, hpaR and hpaY). Genetic engineering approaches were used to clone tyn and hpa genes and then express them, either individually or in tandem, in plasmids and/or bacterial chromosomes, resulting in recombinant bacterial strains able to eliminate tyramine and dopamine from different media. These results enlarge our biochemical and genetic knowledge of the microbial catabolic routes involved in the degradation of aromatic bioamines. Furthermore, they provide potent biotechnological tools to be used in food processing and fermentation as well as new strategies that could be used for pharmacological and gene therapeutic applications in the near future.
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Affiliation(s)
- Mario Arcos
- Departamento de Biología Molecular, Facultad de Veterinaria, Universidad de León, 24007 León, España
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Ellis HR. The FMN-dependent two-component monooxygenase systems. Arch Biochem Biophys 2010; 497:1-12. [PMID: 20193654 DOI: 10.1016/j.abb.2010.02.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 02/13/2010] [Accepted: 02/16/2010] [Indexed: 11/19/2022]
Abstract
The FMN-dependent two-component monooxygenase systems catalyze a diverse range of reactions. These two-component systems are composed of an FMN reductase enzyme and a monooxygenase enzyme that catalyze the oxidation of various substrates. The role of the reductase is to supply reduced flavin to the monooxygenase enzyme, while the monooxygenase enzyme utilizes the reduced flavin to activate molecular oxygen. Unlike flavoproteins with a tightly or covalently bound prosthetic group, these enzymes catalyze the reductive and oxidative half-reaction on two separate enzymes. An interesting feature of these enzymes is their ability to transfer reduced flavin from the reductase to the monooxygenase enzyme. This review covers the reported mechanistic and structural properties of these enzyme systems, and evaluates the mechanism of flavin transfer.
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Affiliation(s)
- Holly R Ellis
- The Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA.
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Saa L, Jaureguibeitia A, Largo E, Llama MJ, Serra JL. Cloning, purification and characterization of two components of phenol hydroxylase from Rhodococcus erythropolis UPV-1. Appl Microbiol Biotechnol 2009; 86:201-11. [PMID: 19787347 DOI: 10.1007/s00253-009-2251-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 09/08/2009] [Accepted: 09/09/2009] [Indexed: 11/24/2022]
Abstract
Phenol hydroxylase that catalyzes the conversion of phenol to catechol in Rhodococcus erythropolis UPV-1 was identified as a two-component flavin-dependent monooxygenase. The two proteins are encoded by the genes pheA1 and pheA2, located very closely in the genome. The sequenced pheA1 gene was composed of 1,629 bp encoding a protein of 542 amino acids, whereas the pheA2 gene consisted of 570 bp encoding a protein of 189 amino acids. The deduced amino acid sequences of both genes showed high homology with several two-component aromatic hydroxylases. The genes were cloned separately in cells of Escherichia coli M15 as hexahistidine-tagged proteins, and the recombinant proteins His(6)PheA1 and His(6)PheA2 were purified and its catalytic activity characterized. His(6)PheA1 exists as a homotetramer of four identical subunits of 62 kDa that has no phenol hydroxylase activity on its own. His(6)PheA2 is a homodimeric flavin reductase, consisting of two identical subunits of 22 kDa, that uses NAD(P)H in order to reduce flavin adenine dinucleotide (FAD), according to a random sequential kinetic mechanism. The reductase activity was strongly inhibited by thiol-blocking reagents. The hydroxylation of phenol in vitro requires the presence of both His(6)PheA1 and His(6)PheA2 components, in addition to NADH and FAD, but the physical interaction between the proteins is not necessary for the reaction.
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Affiliation(s)
- Laura Saa
- Enzyme and Cell Technology Group, Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain
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Suenaga H, Koyama Y, Miyakoshi M, Miyazaki R, Yano H, Sota M, Ohtsubo Y, Tsuda M, Miyazaki K. Novel organization of aromatic degradation pathway genes in a microbial community as revealed by metagenomic analysis. ISME JOURNAL 2009; 3:1335-48. [PMID: 19587775 DOI: 10.1038/ismej.2009.76] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Several types of environmental bacteria that can aerobically degrade various aromatic compounds have been identified. The catabolic genes in these bacteria have generally been found to form operons, which promote efficient and complete degradation. However, little is known about the degradation pathways in bacteria that are difficult to culture in the laboratory. By functionally screening a metagenomic library created from activated sludge, we had earlier identified 91 fosmid clones carrying genes for extradiol dioxygenase (EDO), a key enzyme in the degradation of aromatic compounds. In this study, we analyzed 38 of these fosmids for the presence and organization of novel genes for aromatics degradation. Only two of the metagenomic clones contained complete degradation pathways similar to those found in known aromatic compound-utilizing bacteria. The rest of the clones contained only subsets of the pathway genes, with novel gene arrangements. A circular 36.7-kb DNA form was assembled from the sequences of clones carrying genes belonging to a novel EDO subfamily. This plasmid-like DNA form, designated pSKYE1, possessed genes for DNA replication and stable maintenance as well as a small set of genes for phenol degradation; the encoded enzymes, phenol hydroxylase and EDO, are capable of the detoxification of aromatic compounds. This gene set was found in 20 of the 38 analyzed clones, suggesting that this 'detoxification apparatus' may be widespread in the environment.
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Affiliation(s)
- Hikaru Suenaga
- Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6, Tsukuba, Ibaraki, Japan.
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Li J, Feng J, Li Q, Ma C, Yu B, Gao C, Wu G, Xu P. Both FMNH2 and FADH2 can be utilized by the dibenzothiophene monooxygenase from a desulfurizing bacterium Mycobacterium goodii X7B. BIORESOURCE TECHNOLOGY 2009; 100:2594-2599. [PMID: 19144512 DOI: 10.1016/j.biortech.2008.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 12/03/2008] [Accepted: 12/04/2008] [Indexed: 05/27/2023]
Abstract
To investigate the flavin utilization by dibenzothiophene monooxygenase (DszC), DszC of a desulfurizing bacterium Mycobacterium goodii X7B was purified from the recombinant Escherichia coli. It was shown to be able to utilize either FMNH(2) or FADH(2) when coupled with a flavin reductase that reduces either FMN or FAD. Sequence analysis indicated that DszC was similar to the C(2) component of p-hydroxyphenylacetate hydroxylase from Acinetobacter baumannii, which can use both FADH(2) and FMNH(2) as substrates. Both flavins at high concentrations could inhibit the activity of DszC due to autocatalytic oxidation of reduced flavins. The results suggest that DszC should be reclassified as an FMNH(2) and FADH(2) both-utilizing monooxygenase component and the flavins should be controlled at properly reduced levels to obtain optimal biodesulfurization results.
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Affiliation(s)
- Jingchen Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, People's Republic of China
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Higashioka Y, Kojima H, Sato S, Fukui M. Microbial community analysis at crude oil-contaminated soils targeting the 16S ribosomal RNA, xylM, C23O, and bcr genes. J Appl Microbiol 2009; 107:126-35. [PMID: 19298506 DOI: 10.1111/j.1365-2672.2009.04198.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The analyses targeting multiple functional genes were performed on the samples of crude oil-contaminated soil, to investigate community structures of organisms involved in monoaromatic hydrocarbon degradation. METHODS AND RESULTS Environmental samples were obtained from two sites that were contaminated with different components of crude oil. The analysis on 16S rRNA gene revealed that bacterial community structures were clearly different between the two sites. The cloning analyses were performed by using primers specific for the catabolic genes involved in the aerobic or anaerobic degradation of monoaromatic hydrocarbons, i.e. xylene monooxygenase (xylM), catechol 2,3-dioxygenase (C23O), and benzoyl-CoA reductase (bcr) genes. From the result of xylM gene, it was suggested that there are lineages specific to the respective sites, reflecting the differences of sampling sites. In the analysis of the C23O gene, the results obtained with two primer sets were distinct from each other. A comparison of these suggested that catabolic types of major bacteria carrying this gene were different between the two sites. As for the bcr gene, no amplicon was obtained from one sample. Phylogenetic analysis revealed that the sequences obtained from the other sample were distinct from the known sequences. CONCLUSIONS The differences between the two sites were demonstrated in the analyses of all tested genes. As for aerobic cleavage of the aromatic ring, it was also suggested that analysis using two primer sets provide more detailed information about microbial communities in the contaminated site. SIGNIFICANCE AND IMPACT OF THE STUDY The present study demonstrated that analysis targeting multiple functional genes as molecular markers is practical to examine microbial community in crude oil-contaminated environments.
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Affiliation(s)
- Y Higashioka
- The Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan
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Omokoko B, Jäntges UK, Zimmermann M, Reiss M, Hartmeier W. Isolation of the phe-operon from G. stearothermophilus comprising the phenol degradative meta-pathway genes and a novel transcriptional regulator. BMC Microbiol 2008; 8:197. [PMID: 19014555 PMCID: PMC2590616 DOI: 10.1186/1471-2180-8-197] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 11/13/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Geobacillus stearothermophilus is able to utilize phenol as a sole carbon source. A DNA fragment encoding a phenol hydroxylase catalyzing the first step in the meta-pathway has been isolated previously. Based on these findings a PCR-based DNA walk was performed initially to isolate a catechol 2,3-dioxygenase for biosensoric applications but was continued to elucidate the organisation of the genes encoding the proteins for the metabolization of phenol. RESULTS A 20.2 kb DNA fragment was isolated as a result of the DNA walk. Fifteen open reading frames residing on a low-copy megaplasmid were identified. Eleven genes are co-transcribed in one polycistronic mRNA as shown by reverse transcription-PCR. Ten genes encode proteins, that are directly linked with the meta-cleavage pathway. The deduced amino acid sequences display similarities to a two-component phenol hydroxylase, a catechol 2,3-dioxygenase, a 4-oxalocrotonate tautomerase, a 2-oxopent-4-dienoate hydratase, a 4-oxalocrotonate decarboxylase, a 4-hydroxy-2-oxovalerate aldolase, an acetaldehyde dehydrogenase, a plant-type ferredoxin involved in the reactivation of extradiol dioxygenases and a novel regulatory protein. The only enzymes missing for the complete mineralization of phenol are a 2-hydroxymuconic acid-6-semialdehyde hydrolase and/or 2-hydroxymuconic acid-6-semialdehyde dehydrogenase. CONCLUSION Research on the bacterial degradation of aromatic compounds on a sub-cellular level has been more intensively studied in gram-negative organisms than in gram-positive bacteria. Especially regulatory mechanisms in gram-positive (thermophilic) prokaryotes remain mostly unknown. We isolated the first complete sequence of an operon from a thermophilic bacterium encoding the meta-pathway genes and analyzed the genetic organization. Moreover, the first transcriptional regulator of the phenol metabolism in gram-positive bacteria was identified. This is a first step to elucidate regulatory mechanisms that are likely to be distinct from modes described for gram-negative bacteria.
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Affiliation(s)
- Bastian Omokoko
- Department of Biotechnology, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany.
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Mechanism of 4-nitrophenol oxidation in Rhodococcus sp. Strain PN1: characterization of the two-component 4-nitrophenol hydroxylase and regulation of its expression. J Bacteriol 2008; 190:7367-74. [PMID: 18805976 DOI: 10.1128/jb.00742-08] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
4-Nitrophenol (4-NP) is a toxic product of the hydrolysis of organophosphorus pesticides such as parathion in soil. Rhodococcus sp. strain PN1 degrades 4-NP via 4-nitrocatechol (4-NC) for use as the sole carbon, nitrogen, and energy source. A 5-kb EcoRI DNA fragment previously cloned from PN1 contained a gene cluster (nphRA1A2) involved in 4-NP oxidation. From sequence analysis, this gene cluster is expected to encode an AraC/XylS family regulatory protein (NphR) and a two-component 4-NP hydroxylase (NphA1 and NphA2). A transcriptional assay in a Rhodococcus strain revealed that the transcription of nphA1 is induced by only 4-NP (of several phenolic compounds tested) in the presence of nphR, which is constitutively expressed. Disruption of nphR abolished transcriptional activity, suggesting that nphR encodes a positive regulatory protein. The two proteins of the 4-NP hydroxylase, NphA1 and NphA2, were independently expressed in Escherichia coli and purified by ion-exchange chromatography or affinity chromatography. The purified NphA2 reduced flavin adenine dinucleotide (FAD) with the concomitant oxidation of NADH, while the purified NphA1 oxidized 4-NP into 4-NC almost quantitatively in the presence of FAD, NADH, and NphA2. This functional analysis, in addition to the sequence analysis, revealed that this enzyme system belongs to the two-component flavin-diffusible monooxygenase family. The 4-NP hydroxylase showed comparable oxidation activities for phenol and 4-chlorophenol to that for 4-NP and weaker activities for 3-NP and 4-NC.
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Hawumba JF, Brözel VS, Theron J. Cloning and characterization of a 4-hydroxyphenylacetate 3-hydroxylase from the thermophile Geobacillus sp. PA-9. Curr Microbiol 2007; 55:480-4. [PMID: 17805928 DOI: 10.1007/s00284-007-9016-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 06/21/2007] [Indexed: 11/25/2022]
Abstract
A 4-hydroxyphenylacetic acid (4-HPA) hydroxylase-encoding gene, on a 2.7-kb genomic DNA fragment, was cloned from the thermophile Geobacillus sp. PA-9. The Geobacillus sp. PA-9 4-HPA hydroxylase gene, designated hpaH, encodes a protein of 494 amino acids with a predicted molecular mass of 56.269 Da. The deduced amino-acid sequence of the hpaH gene product displayed <30% amino-acid sequence identity with the larger monooxygenase components of the previously characterized two-component 4-HPA 3-hydroxylases from Escherichia coli W and Klebsiella pneumoniae M5a1. A second oxidoreductase component was not present on the 2.7-kb genomic DNA fragment. The deduced amino-acid sequence of a second C-terminal truncated open reading frame, designated hpaI, exhibited homology to extradiol oxygenases and displayed the highest amino-acid sequence identity (43%) with the 3,4-dihydroxyphenylacetate 2,3-dioxygenase of Arthrobacter globiformis, encoded by mndD. These results, along with catalytic activity observed in crude intracellular extracts prepared from Escherichia coli cells expressing hpaH, is in support of a role for hpaH in the 4-HPA degradative pathway of Geobacillus sp. PA-9.
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Affiliation(s)
- J F Hawumba
- Department of Microbiology and Plant Pathology, University of Pretoria, 0002 Pretoria, South Africa
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Tam LT, Eymann C, Albrecht D, Sietmann R, Schauer F, Hecker M, Antelmann H. Differential gene expression in response to phenol and catechol reveals different metabolic activities for the degradation of aromatic compounds in Bacillus subtilis. Environ Microbiol 2006; 8:1408-27. [PMID: 16872404 DOI: 10.1111/j.1462-2920.2006.01034.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic organic compounds that are present in the environment can have toxic effects or provide carbon sources for bacteria. We report here the global response of Bacillus subtilis 168 to phenol and catechol using proteome and transcriptome analyses. Phenol induced the HrcA, sigmaB and CtsR heat-shock regulons as well as the Spx disulfide stress regulon. Catechol caused the activation of the HrcA and CtsR heat-shock regulons and a thiol-specific oxidative stress response involving the Spx, PerR and FurR regulons but no induction of the sigmaB regulon. The most surprising result was that several catabolite-controlled genes are derepressed by catechol, even if glucose is taken up under these conditions. This derepression of the carbon catabolite control was dependent on the glucose concentration in the medium, as glucose excess increased the derepression of the CcpA-dependent lichenin utilization licBCAH operon and the ribose metabolism rbsRKDACB operon by catechol. Growth and viability experiments with catechol as sole carbon source suggested that B. subtilis is not able to utilize catechol as a carbon-energy source. In addition, the microarray results revealed the very strong induction of the yfiDE operon by catechol of which the yfiE gene shares similarities to glyoxalases/bleomycin resistance proteins/extradiol dioxygenases. Using recombinant His6-YfiE(Bs) we demonstrate that YfiE shows catechol-2,3-dioxygenase activity in the presence of catechol as the metabolite 2-hydroxymuconic semialdehyde was measured. Furthermore, both genes of the yfiDE operon are essential for the growth and viability of B. subtilis in the presence of catechol. Thus, our studies revealed that the catechol-2,3-dioxygenase YfiE is the key enzyme of a meta cleavage pathway in B. subtilis involved in the catabolism of catechol.
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Affiliation(s)
- Le Thi Tam
- Institut für Mikrobiologie, Ernst-Moritz-Arndt-Universität Greifswald, F.-L.-Jahn-Strasse 15, D-17487 Greifswald, Germany
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van Berkel WJH, Kamerbeek NM, Fraaije MW. Flavoprotein monooxygenases, a diverse class of oxidative biocatalysts. J Biotechnol 2006; 124:670-89. [PMID: 16712999 DOI: 10.1016/j.jbiotec.2006.03.044] [Citation(s) in RCA: 509] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 02/21/2006] [Accepted: 03/29/2006] [Indexed: 10/24/2022]
Abstract
During the last decades a large number of flavin-dependent monooxygenases have been isolated and studied. This has revealed that flavoprotein monooxygenases are able to catalyze a remarkable wide variety of oxidative reactions such as regioselective hydroxylations and enantioselective sulfoxidations. These oxidation reactions are often difficult, if not impossible, to be achieved using chemical approaches. Analysis of the available genome sequences has indicated that many more flavoprotein monooxygenases exist and await biocatalytic exploration. Based on the known biochemical properties of a number of flavoprotein monooxygenases and sequence and structural analyses, flavoprotein monooxygenases can be classified into six distinct flavoprotein monooxygenase subclasses. This review provides an inventory of known flavoprotein monooxygenases belonging to these different enzyme subclasses. Furthermore, the biocatalytic potential of a selected number of flavoprotein monooxygenases is highlighted.
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Affiliation(s)
- W J H van Berkel
- Laboratory of Biochemistry, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
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García MT, Ventosa A, Mellado E. Catabolic versatility of aromatic compound-degrading halophilic bacteria. FEMS Microbiol Ecol 2005; 54:97-109. [PMID: 16329976 DOI: 10.1016/j.femsec.2005.03.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 03/03/2005] [Accepted: 03/08/2005] [Indexed: 11/22/2022] Open
Abstract
There is growing interest in the development and optimization of bioremediation processes to deal with environments with high salinity that are contaminated with aromatic compounds. To estimate the diversity of moderately halophilic bacteria that could be used in such processes, enrichments were performed based on growth with a variety of aromatic compounds including phenol as a model pollutant. A group of bacteria that were able to grow over a wide range of salt concentrations were isolated, with the majority of these assigned to the genus Halomonas using phenotypic features and 16S rRNA sequences comparison. PCR amplification with degenerate primers revealed the presence in these isolates of genes encoding ring-cleaving enzymes in the beta-ketoadipate pathway for aromatic catabolism: catechol 1,2-dioxygenase and protocatechuate 3,4-dioxygenase. Furthermore, the activity of these two enzymes was detected in the newly described species Halomonas organivorans. Together, these studies indicate that moderately halophilic bacteria have the potential to catabolize aromatic compounds in environments with high salinity.
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Affiliation(s)
- María Teresa García
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Spain
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Izzo V, Notomista E, Picardi A, Pennacchio F, Di Donato A. The thermophilic archaeon Sulfolobus solfataricus is able to grow on phenol. Res Microbiol 2005; 156:677-89. [PMID: 15921893 DOI: 10.1016/j.resmic.2005.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 04/05/2005] [Accepted: 04/07/2005] [Indexed: 11/16/2022]
Abstract
Many eubacteria use aromatic molecules as a carbon and energy source, but only a few archaea have been reported to grow on aromatics. Degradation of aromatic hydrocarbons by aerobic bacteria is generally divided into an upper pathway, which produces dihydroxylated aromatic intermediates by the action of monooxygenases, and a lower pathway that processes these intermediates down to molecules that enter the citric acid cycle. Recently, analysis of the genome of the thermophilic archaeon Sulfolobus solfataricus revealed the existence of orfs coding for putative enzymes of the degradation pathway of aromatics, i.e., a cluster of orfs coding for the subunits of a hypothetical bacterial multicomponent monooxygenase (SsoMO), an orf coding for a catechol 2,3-dioxygenase (SsoC2,3O), and an orf coding for an enzyme of the lower pathway of the catechol metabolism. In this paper we report that S. solfataricus can efficiently grow on phenol as the sole source of carbon and energy. To our knowledge this is the first report of a thermophilic archaeon able to grow on an aromatic compound under aerobic conditions. Moreover, the cloning and heterologous expression and characterization of the thermophilic SsoC2,3O are reported.
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Affiliation(s)
- Viviana Izzo
- Dipartimento di Biologia strutturale e funzionale, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cinthia, 80126 Naples, Italy
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Thotsaporn K, Sucharitakul J, Wongratana J, Suadee C, Chaiyen P. Cloning and expression of p-hydroxyphenylacetate 3-hydroxylase from Acinetobacter baumannii: evidence of the divergence of enzymes in the class of two-protein component aromatic hydroxylases. ACTA ACUST UNITED AC 2004; 1680:60-6. [PMID: 15451173 DOI: 10.1016/j.bbaexp.2004.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2004] [Revised: 08/10/2004] [Accepted: 08/11/2004] [Indexed: 12/20/2022]
Abstract
The genes encoding for the reductase and oxygenase components of p-hydroxyphenylacetate 3-hydroxylase from Acinetobacter baumannii were cloned and expressed in an E. coli system. The recombinant enzymes were purified and shown to have the same catalytic properties as the native enzyme. Sequence analysis and biochemical studies indicate that the enzyme represents a novel prototype of enzyme in the two-protein component class of aromatic hydroxylases. The C2 component shows little similarity to other oxygenases in the same class, correlating with its uniquely broad flavin specificity. Analysis of the C1 reductase sequence indicates that the binding sites of flavin and NADH mainly reside in the N-terminal half while the C-terminal half may be responsible for HPA-stimulation of NADH oxidation.
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Affiliation(s)
- Kittisak Thotsaporn
- Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, 10400 Bangkok, Thailand
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Kitagawa W, Kimura N, Kamagata Y. A novel p-nitrophenol degradation gene cluster from a gram-positive bacterium, Rhodococcus opacus SAO101. J Bacteriol 2004; 186:4894-902. [PMID: 15262926 PMCID: PMC451640 DOI: 10.1128/jb.186.15.4894-4902.2004] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
p-Nitrophenol (4-NP) is recognized as an environmental contaminant; it is used primarily for manufacturing medicines and pesticides. To date, several 4-NP-degrading bacteria have been isolated; however, the genetic information remains very limited. In this study, a novel 4-NP degradation gene cluster from a gram-positive bacterium, Rhodococcus opacus SAO101, was identified and characterized. The deduced amino acid sequences of npcB, npcA, and npcC showed identity with phenol 2-hydroxylase component B (reductase, PheA2) of Geobacillus thermoglucosidasius A7 (32%), with 2,4,6-trichlorophenol monooxygenase (TcpA) of Ralstonia eutropha JMP134 (44%), and with hydroxyquinol 1,2-dioxygenase (ORF2) of Arthrobacter sp. strain BA-5-17 (76%), respectively. The npcB, npcA, and npcC genes were cloned into pET-17b to construct the respective expression vectors pETnpcB, pETnpcA, and pETnpcC. Conversion of 4-NP was observed when a mixture of crude cell extracts of Escherichia coli containing pETnpcB and pETnpcA was used in the experiment. The mixture converted 4-NP to hydroxyquinol and also converted 4-nitrocatechol (4-NCA) to hydroxyquinol. Furthermore, the crude cell extract of E. coli containing pETnpcC converted hydroxyquinol to maleylacetate. These results suggested that npcB and npcA encode the two-component 4-NP/4-NCA monooxygenase and that npcC encodes hydroxyquinol 1,2-dioxygenase. The npcA and npcC mutant strains, SDA1 and SDC1, completely lost the ability to grow on 4-NP as the sole carbon source. These results clearly indicated that the cloned npc genes play an essential role in 4-NP mineralization in R. opacus SAO101.
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Affiliation(s)
- Wataru Kitagawa
- Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8566, Japan.
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Miyazawa D, Mukerjee-Dhar G, Shimura M, Hatta T, Kimbara K. Genes for Mn(II)-dependent NahC and Fe(II)-dependent NahH located in close proximity in the thermophilic naphthalene and PCB degrader, Bacillus sp. JF8: cloning and characterization. Microbiology (Reading) 2004; 150:993-1004. [PMID: 15073308 DOI: 10.1099/mic.0.26858-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A 10 kb DNA fragment was isolated using a DNA probe derived from the N-terminal amino acid sequence of the extradiol dioxygenase purified from naphthalene-grownBacillussp. JF8, a thermophilic naphthalene and polychlorinated biphenyl degrader. The cloned DNA fragment had six open reading frames, designatednahHLOMmocBnahCbased on sequence homology, of which the products NahH_JF8 and NahC_JF8 were extradiol dioxygenases. Although NahC_JF8 and NahH_JF8 exhibit low homology to known extradiol dioxygenases, the active-site residues and metal ion ligands are conserved. The presence of Mn(II) in culture medium was found to be essential for production of active recombinant NahC_JF8, while Fe(II) was necessary for active recombinant NahH_JF8. Inductively coupled plasma mass spectrometry analysis of active NahC_JF8 identified the cofactor to be manganese, indicating a Mn(II)-dependent extradiol dioxygenase. NahC_JF8 exhibitedKmvalues of 32±5 μM for 1,2-dihydroxynaphthalene and 510±90 μM for 2,3-dihydroxybiphenyl at 60 °C. In cell-free extracts, NahH_JF8 exhibited a broad substrate range for 2,3-dihydroxybiphenyl, catechol, and 3- and 4-methylcatechol at 25 °C. Stability studies on the Mn(II)-dependent NahC_JF8 indicated that it was thermostable, retaining 50 % activity after incubation at 80 °C for 20 min, and it exhibited resistance to EDTA and H2O2. Northern hybridization studies clarified that both NahC_JF8 and NahH_JF8 were induced by naphthalene; RT-PCR showed thatnahHLOMmocBnahCis expressed as a single transcript.
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Affiliation(s)
- Daisuke Miyazawa
- Department of Built Environment, Tokyo Institute of Technology, Yokohama 226-8502, Japan
| | - Gouri Mukerjee-Dhar
- Biotechnology Laboratory, Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540, Japan
| | - Minoru Shimura
- Biotechnology Laboratory, Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540, Japan
| | - Takashi Hatta
- Research Institute of Technology, Okayama University of Science, Okayama 703-8232, Japan
| | - Kazuhide Kimbara
- Biotechnology Laboratory, Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540, Japan
- Department of Built Environment, Tokyo Institute of Technology, Yokohama 226-8502, Japan
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van den Heuvel RHH, Westphal AH, Heck AJR, Walsh MA, Rovida S, van Berkel WJH, Mattevi A. Structural studies on flavin reductase PheA2 reveal binding of NAD in an unusual folded conformation and support novel mechanism of action. J Biol Chem 2003; 279:12860-7. [PMID: 14703520 DOI: 10.1074/jbc.m313765200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The catabolism of toxic phenols in the thermophilic organism Bacillus thermoglucosidasius A7 is initiated by a two-component enzyme system. The smaller flavin reductase PheA2 component catalyzes the NADH-dependent reduction of free FAD according to a ping-pong bisubstrate-biproduct mechanism. The reduced FAD is then used by the larger oxygenase component PheA1 to hydroxylate phenols to the corresponding catechols. We have determined the x-ray structure of PheA2 containing a bound FAD cofactor (2.2 A), which is the first structure of a member of this flavin reductase family. We have also determined the x-ray structure of reduced holo-PheA2 in complex with oxidized NAD (2.1 A). PheA2 is a single domain homodimeric protein with each FAD-containing subunit being organized around a six-stranded beta-sheet and a capping alpha-helix. The tightly bound FAD prosthetic group (K(d) = 10 nm) binds near the dimer interface, and the re face of the FAD isoalloxazine ring is fully exposed to solvent. The addition of NADH to crystalline PheA2 reduced the flavin cofactor, and the NAD product was bound in a wide solvent-accessible groove adopting an unusual folded conformation with ring stacking. This is the first observation of an enzyme that is very likely to react with a folded compact pyridine nucleotide. The PheA2 crystallographic models strongly suggest that reactive exogenous FAD substrate binds in the NADH cleft after release of NAD product. Nanoflow electrospray mass spectrometry data indeed showed that PheA2 is able to bind one FAD cofactor and one FAD substrate. In conclusion, the structural data provide evidence that PheA2 contains a dual binding cleft for NADH and FAD substrate, which alternate during catalysis.
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Affiliation(s)
- Robert H H van den Heuvel
- Department of Genetics and Microbiology, University of Pavia, via Abbiategrasso 207, 27100 Pavia, Italy.
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Kirchner U, Westphal AH, Müller R, van Berkel WJH. Phenol hydroxylase from Bacillus thermoglucosidasius A7, a two-protein component monooxygenase with a dual role for FAD. J Biol Chem 2003; 278:47545-53. [PMID: 12968028 DOI: 10.1074/jbc.m307397200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel phenol hydroxylase (PheA) that catalyzes the first step in the degradation of phenol in Bacillus thermoglucosidasius A7 is described. The two-protein system, encoded by the pheA1 and pheA2 genes, consists of an oxygenase (PheA1) and a flavin reductase (PheA2) and is optimally active at 55 degrees C. PheA1 and PheA2 were separately expressed in recombinant Escherichia coli BL21(DE3) pLysS cells and purified to apparent homogeneity. The pheA1 gene codes for a protein of 504 amino acids with a predicted mass of 57.2 kDa. PheA1 exists as a homodimer in solution and has no enzyme activity on its own. PheA1 catalyzes the efficient ortho-hydroxylation of phenol to catechol when supplemented with PheA2 and FAD/NADH. The hydroxylase activity is strictly FAD-dependent, and neither FMN nor riboflavin can replace FAD in this reaction. The pheA2 gene codes for a protein of 161 amino acids with a predicted mass of 17.7 kDa. PheA2 is also a homodimer, with each subunit containing a highly fluorescent FAD prosthetic group. PheA2 catalyzes the NADH-dependent reduction of free flavins according to a Ping Pong Bi Bi mechanism. PheA2 is structurally related to ferric reductase, an NAD(P)H-dependent reductase from the hyperthermophilic Archaea Archaeoglobus fulgidus that catalyzes the flavin-mediated reduction of iron complexes. However, PheA2 displays no ferric reductase activity and is the first member of a newly recognized family of short-chain flavin reductases that use FAD both as a substrate and as a prosthetic group.
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Affiliation(s)
- Ulrike Kirchner
- Department of Technical Biochemistry, Biotechnology II, Technical University Hamburg-Harburg, Denickestrasse 15, D-21071 Hamburg, Germany
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Yang L, Zhou Z, Xiao L, Wang X. Chemical and biological regeneration of HDTMA-modified montmorillonite after sorption with phenol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:5057-5061. [PMID: 14620838 DOI: 10.1021/es0342493] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Hexadecyltrimethylammonium (HDTMA)-modified montmorillonite (HMM) has recently been recognized as a potential sorbentto remove organic contaminants from environmental systems. Potential applications of this material highly depend on the efficiency of regenerating contaminant-sorbing HMM. In this study, we investigated a chemical (NaOH solution) and a biological (yeast Pityrosporum sp.) method to regenerate phenol-sorbing HMM. Our results showed that the sorption coefficient of phenol to HMM is not a linear function of the ratio of the substitution of HDTMA in HMM. Chemical regeneration of HMMs (0-0.7 times of its cation exchange capacity (CEC)) proved the existence of a phenol residual amount of about 3 mg x g(-1) in the HMMs tested when aqueous pH is maintained above 11. In addition, the obvious deductions in the sorption capacity of the chemically regenerated HMMs were observed after four cycles of sorption-regeneration. However, the sorption capacities of intermediate substituted HMMs (0.3-0.7 CEC) can be completely restored by bioregeneration with yeast for extended cycles of reuse. The results imply that the bioregeneration method with yeast could be a promising technique for in-situ bioremediation of phenol-contaminated groundwater in the subsurface or for treatment of phenol containing wastewater.
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Affiliation(s)
- Liuyan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210093, PR China.
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TAKEO MASAHIRO, YASUKAWA TAKESHI, ABE YOSHIKATSU, NIIHARA SANAE, MAEDA YOSHIMICHI, NEGORO SEIJI. Cloning and Characterization of a 4-Nitrophenol Hydroxylase Gene Cluster from Rhodococcus sp. PN1. J Biosci Bioeng 2003. [DOI: 10.1263/jbb.95.139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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