1
|
Simpson JB, Sekela JJ, Carry BS, Beaty V, Patel S, Redinbo MR. Diverse but desolate landscape of gut microbial azoreductases: A rationale for idiopathic IBD drug response. Gut Microbes 2023; 15:2203963. [PMID: 37122075 PMCID: PMC10132220 DOI: 10.1080/19490976.2023.2203963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/01/2023] [Accepted: 04/04/2023] [Indexed: 05/02/2023] Open
Abstract
Prodrugs reliant on microbial activation are widely used but exhibit a range of efficacies that remain poorly understood. The anti-inflammatory compound 5-aminosalicylic acid (5-ASA), which is packaged in a variety of azo-linked prodrugs provided to most Ulcerative Colitis (UC) patients, shows confounding inter-individual variabilities in response. Such prodrugs must be activated by azo-bond reduction to form 5-ASA, a process that has been attributed to both enzymatic and non-enzymatic catalysis. Gut microbial azoreductases (AzoRs) are the first catalysts shown to activate azo-linked drugs and to metabolize toxic azo-chemicals. Here, we chart the scope of the structural and functional diversity of AzoRs in health and in patients with the inflammatory bowel diseases (IBDs) UC and Crohn's Disease (CD). Using structural metagenomics, we define the landscape of gut microbial AzoRs in 413 healthy donor and 1059 IBD patient fecal samples. Firmicutes encode a significantly higher number of unique AzoRs compared to other phyla. However, structural and biochemical analyses of distinct AzoRs from the human microbiome reveal significant differences between prevalent orthologs in the processing of toxic azo-dyes, and their generally poor activation of IBD prodrugs. Furthermore, while individuals with IBD show higher abundances of AzoR-encoding gut microbial taxa than healthy controls, the overall abundance of AzoR-encoding microbes is markedly low in both disease and health. Together, these results establish that gut microbial AzoRs are functionally diverse but sparse in both health and disease, factors that may contribute to non-optimal processing of azo-linked prodrugs and idiopathic IBD drug responses.
Collapse
Affiliation(s)
- Joshua B. Simpson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Josh J. Sekela
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Benjamin S. Carry
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Violet Beaty
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Shakshi Patel
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Matthew. R. Redinbo
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biochemistry and Biophysics, Department of Microbiology and Immunology, and the Integrated Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
2
|
Zhao J, Zhang B, Mao Q, Ping K, Zhang P, Lin F, Liu D, Feng Y, Sun M, Zhang Y, Li QH, Zhang T, Mou Y, Wang S. Discovery of a Colon-Targeted Azo Prodrug of Tofacitinib through the Establishment of Colon-Specific Delivery Systems Constructed by 5-ASA-PABA-MAC and 5-ASA-PABA-Diamine for the Treatment of Ulcerative Colitis. J Med Chem 2022; 65:4926-4948. [PMID: 35275619 DOI: 10.1021/acs.jmedchem.1c02166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To mitigate the systemic adverse effects of tofacitinib, 5-ASA-PABA-MAC and 5-ASA-PABA-diamine colon-specific delivery systems were constructed, and tofacitinib azo prodrugs 9 and 20a-20g were synthesized accordingly. The release studies suggested that these systems could effectively release tofacitinib in vitro, and the 5-ASA-PABA-diamine system could successfully realize the colon targeting of tofacitinib in vivo. Specifically, compound 20g displayed a 3.67-fold decrease of plasma AUC(tofacitinib, 0-∞) and a 9.61-fold increase of colonic AUC(tofacitinib, 0-12h), compared with tofacitinib at a molar equivalent oral dose. Moreover, mouse models suggested that compound 20g (1.5 mg/kg) could achieve roughly the same efficacy against ulcerative colitis compared with tofacitinib (10 mg/kg) and did not impair natural killer cells. These results demonstrated the feasibility of compound 20g as an effective alternative to mitigate the systemic adverse effects of tofacitinib, and 5-ASA-PABA-MAC and 5-ASA-PABA-diamine systems were proven to be effective for colon-specific drug delivery.
Collapse
Affiliation(s)
- Jiaxing Zhao
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Bing Zhang
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Qing Mao
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Kunqi Ping
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Peng Zhang
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Fengwei Lin
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Dan Liu
- Shenyang Hinewy Pharmaceutical Technology Co., Ltd., 41 Liutang Road, Shenhe District, Shenyang 110016, China
| | - Yao Feng
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Ming Sun
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Yan Zhang
- Department of Pharmacology, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Qiu Hua Li
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Tingjian Zhang
- School of Pharmacy, China Medical University, 77 Puhe Road, North New Area, Shenyang 110122, China
| | - Yanhua Mou
- Department of Pharmacology, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| | - Shaojie Wang
- Key Laboratory of Structure-Based Drugs Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Culture Road, Shenhe District, Shenyang 110016, China
| |
Collapse
|
3
|
Ngo ACR, Qi J, Juric C, Bento I, Tischler D. Identification of molecular basis that underlie enzymatic specificity of AzoRo from Rhodococcus opacus 1CP: A potential NADH:quinone oxidoreductase. Arch Biochem Biophys 2022; 717:109123. [PMID: 35051387 DOI: 10.1016/j.abb.2022.109123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/22/2021] [Accepted: 01/15/2022] [Indexed: 12/15/2022]
Abstract
Azo dyes are important to various industries such as textile industries. However, these dyes are known to comprise toxic, mutagenic, and carcinogenic representatives. Several approaches have already been employed to mitigate the problem such as the use of enzymes. Azoreductases have been well-studied in its capability to reduce azo dyes. AzoRo from Rhodococcus opacus 1CP has been found to be accepting only methyl red as a substrate, surmising that the enzyme may have a narrow active site. To determine the active site configuration of AzoRo at atomic level and identify the key residues involved in substrate binding and enzyme specificity, we have determined the crystal structure of holo-AzoRo and employed a rational design approach to generate AzoRo variants. The results reported here show that AzoRo has a different configuration of the active site when compared with other bacterial NAD(P)H azoreductases, having other key residues playing a role in the substrate binding and restricting the enzyme activity towards different azo dyes. Moreover, it was observed that AzoRo has only about 50% coupling yield to methyl red and p-benzoquinone - giving rise to the possibility that NADH oxidation still occurs even during catalysis. Results also showed that AzoRo is more active and more efficient towards quinones (about four times higher than methyl red).
Collapse
Affiliation(s)
- Anna Christina R Ngo
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Jingxian Qi
- Environmental Microbiology, Faculty of Chemistry and Physics, TU Bergakademie Freiberg, Leipziger Str. 29, 09599, Freiberg, Germany
| | - Cindy Juric
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Isabel Bento
- European Molecular Biology Laboratory, EMBL c/o DESY, Building 25A, Notkestr. 85, 22607, Hamburg, Germany
| | - Dirk Tischler
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany.
| |
Collapse
|
4
|
Romero E, Savino S, Fraaije MW, Lončar N. Mechanistic and Crystallographic Studies of Azoreductase AzoA from Bacillus wakoensis A01. ACS Chem Biol 2020; 15:504-512. [PMID: 31967777 PMCID: PMC7040913 DOI: 10.1021/acschembio.9b00970] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 01/22/2020] [Indexed: 01/26/2023]
Abstract
The azoreductase AzoA from the alkali-tolerant Bacillus wakoensis A01 has been studied to reveal its structural and mechanistic details. For this, a recombinant expression system was developed which yields impressive amounts of fully active enzyme. The purified holo enzyme is remarkably solvent-tolerant and thermostable with an apparent melting temperature of 71 °C. The dimeric enzyme contains FMN as a prosthetic group and is strictly NADH dependent. While AzoA shows a negligible ability to use molecular oxygen as an electron acceptor, it is efficient in reducing various azo dyes and quinones. The kinetic and catalytic mechanism has been studied in detail using steady state kinetic analyses and stopped-flow studies. The data show that AzoA performs quinone and azo dye reductions via a two-electron transfer. Moreover, quinones were shown to be much better substrates (kcat values of 100-400 s-1 for several naphtoquinones) when compared with azo dyes. This suggests that the physiological role of AzoA and sequence-related microbial reductases is linked to quinone reductions and that they can better be annotated as quinone reductases. The structure of AzoA has been determined in complex with FMN at 1.8 Å resolution. AzoA displays unique features in the active site providing clues for explaining its catalytic and thermostability features. An uncommon loop, when compared with sequence-related reductases, forms an active site lid with Trp60 acting as an anchor. Several Trp60 mutants have been analyzed disclosing an important role of this residue in the stability of AzoA, while they retained activity. Structural details are discussed in relation to other azo and quinone reductases. This study provides new insights into the molecular functioning of AzoA and sequence-related reductases.
Collapse
Affiliation(s)
- Elvira Romero
- Molecular
Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Simone Savino
- Molecular
Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Marco W. Fraaije
- Molecular
Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Nikola Lončar
- GECCO
Biotech, Nijenborgh 4, 9747AG Groningen, The Netherlands
- Molecular
Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| |
Collapse
|
5
|
Suzuki H. Remarkable diversification of bacterial azoreductases: primary sequences, structures, substrates, physiological roles, and biotechnological applications. Appl Microbiol Biotechnol 2019; 103:3965-3978. [PMID: 30941462 DOI: 10.1007/s00253-019-09775-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 12/12/2022]
Abstract
Azoreductases reductively cleave azo linkages by using NAD(P)H as an electron donor. The enzymes are widely found in bacteria and act on numerous azo dyes, which allow various unique applications. This review describes primary amino acid sequences, structures, substrates, physiological roles, and biotechnological applications of bacterial azoreductases to discuss their remarkable diversification. According to primary sequences, azoreductases were classified phylogenetically into four main clades. Most members of clades I-III are flavoproteins, whereas clade IV members include flavin-free azoreductases. Clades I and II prefer NADPH and NADH, respectively, as electron donors, whereas other members generally use both. Several enzymes formed no clades; moreover, some bacteria produce azoreductases with longer primary structures than those hitherto identified, which implies further diversification of bacterial azoreductases. The crystal structures commonly reveal the Rossmann folds; however, ternary structures are moderately varied with different quaternary conformation. Although physiological roles are obscure, several azoreductases have been shown to act on metabolites such as flavins, quinones, and metal ions more efficiently than on azo dyes. Considering that many homologs exclusively act on these metabolites, it is possible that azoreductases are actually side activities of versatile reductases that act on various substrates with different specificities. In parallel, this idea raises the possibility that homologous enzymes, even if these are already defined as other types of reductases, widely harbor azoreductase activities. Although azoreductases for which their genes have been identified are not abundant, it may be simple to identify azoreductases of biotechnological importance that have novel substrate specificities.
Collapse
Affiliation(s)
- Hirokazu Suzuki
- Faculty of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan. .,Center for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8552, Japan.
| |
Collapse
|
6
|
|
7
|
Chalansonnet V, Mercier C, Orenga S, Gilbert C. Identification of Enterococcus faecalis enzymes with azoreductases and/or nitroreductase activity. BMC Microbiol 2017; 17:126. [PMID: 28545445 PMCID: PMC5445473 DOI: 10.1186/s12866-017-1033-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/15/2017] [Indexed: 01/03/2023] Open
Abstract
Background Nitroreductases, NAD(P)H dependent flavoenzymes, are found in most of bacterial species. Even if Enterococcus faecalis strains seems to present such activity because of their sensitivity to nitrofurans, no enzyme has been described. Nitroreductases were separated of others reductases due to their capacity to reduce nitro compounds. They are further classified based on their preference in cofactor: NADH and/or NADPH. However, recently, azoreductases have been studied for their strong activity on nitro compounds, especially nitro pro-drugs. This result suggests a crossing in azo and nitro reductase activities. For the moment, no nitroreductase was demonstrated to possess azoreductase activity. But due to sequence divergence and activity specificity linked to substrates, activity prediction is not evident and biochemical characterisation remains necessary. Identifying enzymes active on these two classes of compounds: azo and nitro is of interest to consider a common physiological role. Results Four putative nitroreductases, EF0404, EF0648, EF0655 and EF1181 from Enterococcus faecalis V583 were overexpressed as his-tagged recombinant proteins in Escherichia coli and purified following a native or a denaturing/renaturing protocol. EF0648, EF0655 and EF1181 showed nitroreductase activity and their cofactor preferences were in agreement with their protein sequence phylogeny. EF0404 showed both nitroreductase and azoreductase activity. Interestingly, the biochemical characteristics (substrate and cofactor specificity) of EF0404 resembled the properties of the known azoreductase AzoA. But its sequence matched within nitroreductase group, the same as EF0648. Conclusions We here demonstrate nitroreductase activity of the putative reductases identified in the Enterococcus faecalis V583 genome. We identified the first nitroreductase able to reduce directly an azo compound, while its protein sequence is close to others nitroreductases. Consequently, it highlights the difficulty in classifying these enzymes solely on the basis of protein sequence alignment and hereby the necessity to experimentally demonstrate the activity. The results provide additional data to consider a broader functionality of these reductases.
Collapse
Affiliation(s)
- Valérie Chalansonnet
- bioMérieux, 3 route de port Michaud, 38390, La Balme les Grottes, France. .,CIRI, International Center for Infectiology Research, Legionella pathogenesis group, Université de Lyon, Lyon, France. .,INSERM, U1111, Lyon, France. .,Ecole Normale Supérieure de Lyon, F-69364, Lyon, France. .,Université Lyon 1, F-69622, Lyon, France. .,CNRS, UMR5308, Lyon, France.
| | - Claire Mercier
- bioMérieux, 3 route de port Michaud, 38390, La Balme les Grottes, France.,CIRI, International Center for Infectiology Research, Legionella pathogenesis group, Université de Lyon, Lyon, France.,INSERM, U1111, Lyon, France.,Ecole Normale Supérieure de Lyon, F-69364, Lyon, France.,Université Lyon 1, F-69622, Lyon, France.,CNRS, UMR5308, Lyon, France
| | - Sylvain Orenga
- bioMérieux, 3 route de port Michaud, 38390, La Balme les Grottes, France
| | - Christophe Gilbert
- CIRI, International Center for Infectiology Research, Legionella pathogenesis group, Université de Lyon, Lyon, France.,INSERM, U1111, Lyon, France.,Ecole Normale Supérieure de Lyon, F-69364, Lyon, France.,Université Lyon 1, F-69622, Lyon, France.,CNRS, UMR5308, Lyon, France
| |
Collapse
|
8
|
Ryan A. Azoreductases in drug metabolism. Br J Pharmacol 2016; 174:2161-2173. [PMID: 27487252 DOI: 10.1111/bph.13571] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 02/06/2023] Open
Abstract
Azoreductases are flavoenzymes that have been characterized in a range of prokaryotes and eukaryotes. Bacterial azoreductases are associated with the activation of two classes of drug, azo drugs for the treatment of inflammatory bowel disease and nitrofuran antibiotics. The mechanism of reduction of azo compounds is presented; it requires tautomerisation of the azo compound to a quinoneimine and provides a unifying mechanism for the reduction of azo and quinone substrates by azoreductases. The importance of further work in the characterization of azoreductases from enteric bacteria is highlighted to aid in the development of novel drugs for the treatment of colon related disorders. Human azoreductases are known to play a crucial role in the metabolism of a number of quinone-containing cancer chemotherapeutic drugs. The mechanism of hydride transfer to quinones, which is shared not only between eukaryotic and prokaryotic azoreductases but also the wider family of NAD(P)H quinone oxidoreductases, is outlined. The importance of common single nucleotide polymorphisms (SNPs) in human azoreductases is described not only in cancer prognosis but also with regard to their effects on the efficacy of quinone drug-based cancer chemotherapeutic regimens. This highlights the need to screen patients for azoreductase SNPs ahead of treatment with these regimens. LINKED ARTICLES This article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.14/issuetoc.
Collapse
Affiliation(s)
- Ali Ryan
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, UK
| |
Collapse
|
9
|
Identification of novel members of the bacterial azoreductase family in Pseudomonas aeruginosa. Biochem J 2015; 473:549-58. [PMID: 26621870 DOI: 10.1042/bj20150856] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/30/2015] [Indexed: 11/17/2022]
Abstract
Azoreductases are a family of diverse enzymes found in many pathogenic bacteria as well as distant homologues being present in eukarya. In addition to having azoreductase activity, these enzymes are also suggested to have NAD(P)H quinone oxidoreductase (NQO) activity which leads to a proposed role in plant pathogenesis. Azoreductases have also been suggested to play a role in the mammalian pathogenesis of Pseudomonas aeruginosa. In view of the importance of P. aeruginosa as a pathogen, we therefore characterized recombinant enzymes following expression of a group of putative azoreductase genes from P. aeruginosa expressed in Escherichia coli. The enzymes include members of the arsenic-resistance protein H (ArsH), tryptophan repressor-binding protein A (WrbA), modulator of drug activity B (MdaB) and YieF families. The ArsH, MdaB and YieF family members all show azoreductase and NQO activities. In contrast, WrbA is the first enzyme to show NQO activity but does not reduce any of the 11 azo compounds tested under a wide range of conditions. These studies will allow further investigation of the possible role of these enzymes in the pathogenesis of P. aeruginosa.
Collapse
|
10
|
Mahmood S, Khalid A, Arshad M, Mahmood T, Crowley DE. Detoxification of azo dyes by bacterial oxidoreductase enzymes. Crit Rev Biotechnol 2015; 36:639-51. [DOI: 10.3109/07388551.2015.1004518] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Shahid Mahmood
- Department of Environmental Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan,
| | - Azeem Khalid
- Department of Environmental Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan,
| | - Muhammad Arshad
- Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad, Pakistan, and
| | - Tariq Mahmood
- Department of Environmental Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan,
| | - David E. Crowley
- Department of Environmental Sciences, University of California, Riverside, CA, USA
| |
Collapse
|
11
|
Nagendranatha Reddy C, Naresh Kumar A, Annie Modestra J, Venkata Mohan S. Induction of anoxic microenvironment in multi-phase metabolic shift strategy during periodic discontinuous batch mode operation enhances treatment of azo dye wastewater. BIORESOURCE TECHNOLOGY 2014; 165:241-249. [PMID: 24650617 DOI: 10.1016/j.biortech.2014.02.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/05/2014] [Accepted: 02/09/2014] [Indexed: 06/03/2023]
Abstract
Variation in anoxic microenvironment (multi-phase (MP) metabolic shift strategy) during cycle operation of periodic discontinuous batch/sequencing batch (PDBR/SBR) mode operation showed enhanced degradation of recalcitrant azo dye (C.I. Acid Black 10B) at higher dye load (1250mg/l). The process performance was evaluated by varying anoxic phasing period during cycle operation. Before multiphase (BMP) operation with 2.1% of anoxic period showed color/COD removal efficiency of 41.9%/46.3%. Increment in anoxic period responded favorable in enhancing treatment efficiency [AMPI (16.2%), 49.4%/52.4%; AMPII (26.6%), 54.7%/57.2%; AMPIII (34.9%), 58.4%/61.5%]. Relatively higher bio-electrochemical activity, persistent reductive behavior (redox catalytic currents, 0.26/-0.72μA), prevalence of redox shuttlers (Fe-S proteins, cytochromes, quinones) facilitating enhanced electron transfer by minimization of associated losses and higher enzyme activities were observed with induction of anoxic phase. Anoxic condition shifts system microenvironment between oxidation and reduction assisting reduction of dye to its intermediates followed by their mineralization.
Collapse
Affiliation(s)
- C Nagendranatha Reddy
- Academy of Scientific and Innovative Research (AcSIR), Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
| | - A Naresh Kumar
- Academy of Scientific and Innovative Research (AcSIR), Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
| | - J Annie Modestra
- Academy of Scientific and Innovative Research (AcSIR), Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India
| | - S Venkata Mohan
- Academy of Scientific and Innovative Research (AcSIR), Bioengineering and Environmental Centre (BEEC), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
| |
Collapse
|
12
|
Ryan A, Kaplan E, Nebel JC, Polycarpou E, Crescente V, Lowe E, Preston GM, Sim E. Identification of NAD(P)H quinone oxidoreductase activity in azoreductases from P. aeruginosa: azoreductases and NAD(P)H quinone oxidoreductases belong to the same FMN-dependent superfamily of enzymes. PLoS One 2014; 9:e98551. [PMID: 24915188 PMCID: PMC4051601 DOI: 10.1371/journal.pone.0098551] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/05/2014] [Indexed: 01/15/2023] Open
Abstract
Water soluble quinones are a group of cytotoxic anti-bacterial compounds that are secreted by many species of plants, invertebrates, fungi and bacteria. Studies in a number of species have shown the importance of quinones in response to pathogenic bacteria of the genus Pseudomonas. Two electron reduction is an important mechanism of quinone detoxification as it generates the less toxic quinol. In most organisms this reaction is carried out by a group of flavoenzymes known as NAD(P)H quinone oxidoreductases. Azoreductases have previously been separate from this group, however using azoreductases from Pseudomonas aeruginosa we show that they can rapidly reduce quinones. Azoreductases from the same organism are also shown to have distinct substrate specificity profiles allowing them to reduce a wide range of quinones. The azoreductase family is also shown to be more extensive than originally thought, due to the large sequence divergence amongst its members. As both NAD(P)H quinone oxidoreductases and azoreductases have related reaction mechanisms it is proposed that they form an enzyme superfamily. The ubiquitous and diverse nature of azoreductases alongside their broad substrate specificity, indicates they play a wide role in cellular survival under adverse conditions.
Collapse
Affiliation(s)
- Ali Ryan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, United Kingdom
| | - Elise Kaplan
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Jean-Christophe Nebel
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, United Kingdom
| | - Elena Polycarpou
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, United Kingdom
| | - Vincenzo Crescente
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, United Kingdom
| | - Edward Lowe
- Laboratory of Molecular Biophysics, Biochemistry Department, University of Oxford, Oxford, United Kingdom
| | - Gail M. Preston
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Edith Sim
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- Faculty of Science, Engineering and Computing, Kingston University, Kingston upon Thames, United Kingdom
| |
Collapse
|
13
|
Feng J, Cerniglia CE, Chen H. Toxicological significance of azo dye metabolism by human intestinal microbiota. Front Biosci (Elite Ed) 2012; 4. [PMID: 22201895 PMCID: PMC5870118 DOI: 10.2741/400] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Approximately 0.7 million tons of azo dyes are synthesized each year. Azo dyes are composed of one or more R₁-N=N-R₂ linkages. Studies have shown that both mammalian and microbial azoreductases cleave the azo bonds of the dyes to form compounds that are potentially genotoxic. The human gastrointestinal tract harbors a diverse microbiota comprised of at least several thousand species. Both water-soluble and water-insoluble azo dyes can be reduced by intestinal bacteria. Some of the metabolites produced by intestinal microbiota have been shown to be carcinogenic to humans although the parent azo dyes may not be classified as being carcinogenic. Azoreductase activity is commonly found in intestinal bacteria. Three types of azoreductases have been characterized in bacteria. They are flavin dependent NADH preferred azoreductase, flavin dependent NADPH preferred azoreductase, and flavin free NADPH preferred azoreductase. This review highlights how azo dyes are metabolized by intestinal bacteria, mechanisms of azo reduction, and the potential contribution in the carcinogenesis/mutagenesis of the reduction of the azo dyes by intestinal microbiota.
Collapse
Affiliation(s)
- Jinhui Feng
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| | - Carl E. Cerniglia
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| | - Huizhong Chen
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| |
Collapse
|
14
|
Feng J, Cerniglia CE, Chen H. Toxicological significance of azo dye metabolism by human intestinal microbiota. Front Biosci (Elite Ed) 2012; 4:568-586. [PMID: 22201895 PMCID: PMC5870118 DOI: 10.2741/e400] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Approximately 0.7 million tons of azo dyes are synthesized each year. Azo dyes are composed of one or more R₁-N=N-R₂ linkages. Studies have shown that both mammalian and microbial azoreductases cleave the azo bonds of the dyes to form compounds that are potentially genotoxic. The human gastrointestinal tract harbors a diverse microbiota comprised of at least several thousand species. Both water-soluble and water-insoluble azo dyes can be reduced by intestinal bacteria. Some of the metabolites produced by intestinal microbiota have been shown to be carcinogenic to humans although the parent azo dyes may not be classified as being carcinogenic. Azoreductase activity is commonly found in intestinal bacteria. Three types of azoreductases have been characterized in bacteria. They are flavin dependent NADH preferred azoreductase, flavin dependent NADPH preferred azoreductase, and flavin free NADPH preferred azoreductase. This review highlights how azo dyes are metabolized by intestinal bacteria, mechanisms of azo reduction, and the potential contribution in the carcinogenesis/mutagenesis of the reduction of the azo dyes by intestinal microbiota.
Collapse
Affiliation(s)
- Jinhui Feng
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| | - Carl E. Cerniglia
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| | - Huizhong Chen
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
| |
Collapse
|
15
|
Ryan A, Kaplan E, Laurieri N, Lowe E, Sim E. Activation of nitrofurazone by azoreductases: multiple activities in one enzyme. Sci Rep 2011; 1:63. [PMID: 22355582 PMCID: PMC3216550 DOI: 10.1038/srep00063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 07/28/2011] [Indexed: 11/10/2022] Open
Abstract
Azoreductases are well known for azo pro-drug activation by gut flora. We show that azoreductases have a wider role in drug metabolism than previously thought as they can also reduce and hence activate nitrofurazone. Nitrofurazone, a nitroaromatic drug, is a broad spectrum antibiotic which has until now been considered as activated in bacteria by nitroreductases. The structure of the azoreductase with nitrofurazone bound was solved at 2.08 Å and shows nitrofurazone in an active conformation. Based on the structural information, the kinetics and stoichiometry of nitrofurazone reduction by azoreductase from P. aeruginosa, we propose a mechanism of activation which accounts for the ability of azoreductases to reduce both azo and nitroaromatic drugs. This mode of activation can explain the cytotoxic side-effects of nitrofurazone through human azoreductase homologues.
Collapse
Affiliation(s)
- Ali Ryan
- Pharmacology Department, University of Oxford, OX1 3QT
- Faculty of Science, Engineering and Computing, Kingston University, KT1 2EE
| | - Elise Kaplan
- Pharmacology Department, University of Oxford, OX1 3QT
| | | | - Edward Lowe
- Laboratory of Molecular Biophysics, Biochemistry Department, University of Oxford, OX1 3QU
| | - Edith Sim
- Pharmacology Department, University of Oxford, OX1 3QT
- Faculty of Science, Engineering and Computing, Kingston University, KT1 2EE
| |
Collapse
|
16
|
Effects of Orange II and Sudan III azo dyes and their metabolites on Staphylococcus aureus. J Ind Microbiol Biotechnol 2011; 38:1729-38. [PMID: 21451978 DOI: 10.1007/s10295-011-0962-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/12/2011] [Indexed: 12/25/2022]
Abstract
Azo dyes are widely used in the plastic, paper, cosmetics, food, and pharmaceutical industries. Some metabolites of these dyes are potentially genotoxic. The toxic effects of azo dyes and their potential reduction metabolites on Staphylococcus aureus ATCC BAA 1556 were studied. When the cultures were incubated with 6, 18, and 36 μg/ml of Orange II and Sudan III for 48 h, 76.3, 68.5, and 61.7% of Orange II and 97.8, 93.9, and 75.8% of Sudan III were reduced by the bacterium, respectively. In the presence of 36 μg/ml Sudan III, the cell viability of the bacterium decreased to 61.9% after 48 h of incubation, whereas the cell viability of the control culture without the dye was 71.5%. Moreover, the optical density of the bacterial cultures at 10 h decreased from 0.74 to 0.55, indicating that Sudan III is able to inhibit growth of the bacterium. However, Orange II had no significant effects on either cell growth or cell viability of the bacterium at the tested concentrations. 1-Amino-2-naphthol, a metabolite common to Orange II and Sudan III, was capable of inhibiting cell growth of the bacterium at 1 μg/ml and completely stopped bacterial cell growth at 24-48 μg/ml. On the other hand, the other metabolites of Orange II and Sudan III, namely sulfanilic acid, p-phenylenediamine, and aniline, showed no significant effects on cell growth. p-Phenylenediamine exhibited a synergistic effect with 1-amino-2-naphthol on cell growth inhibition. All of the dye metabolites had no significant effects on cell viability of the bacterium.
Collapse
|
17
|
Correia B, Chen Z, Mendes S, Martins LO, Bento I. Crystallization and preliminary X-ray diffraction analysis of the azoreductase PpAzoR from Pseudomonas putida MET94. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:121-3. [PMID: 21206041 PMCID: PMC3079989 DOI: 10.1107/s1744309110048220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 11/18/2010] [Indexed: 11/10/2022]
Abstract
PpAzoR, an FMN-dependent NADPH azoreductase from Pseudomonas putida MET94, has been crystallized using the sitting-drop vapour-diffusion technique. The crystals diffracted to 1.6 Å resolution using synchrotron radiation and belonged to the orthorhombic space group F222, with unit-cell parameters a=72.1, b=95.5, c=146.1 Å. Data sets were collected from the native protein to 2.2 Å resolution using in-house equipment and to 1.6 Å resolution using synchrotron radiation and the three-dimensional structure was determined by the molecular-replacement method.
Collapse
Affiliation(s)
- Bruno Correia
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-257 Oeiras, Portugal
| | - Zhenjia Chen
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-257 Oeiras, Portugal
| | - Sónia Mendes
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-257 Oeiras, Portugal
| | - Lígia O. Martins
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-257 Oeiras, Portugal
| | - Isabel Bento
- Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-257 Oeiras, Portugal
| |
Collapse
|
18
|
Ryan A, Wang CJ, Laurieri N, Westwood I, Sim E. Reaction mechanism of azoreductases suggests convergent evolution with quinone oxidoreductases. Protein Cell 2010; 1:780-90. [PMID: 21203919 DOI: 10.1007/s13238-010-0090-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 06/28/2010] [Indexed: 01/17/2023] Open
Abstract
Azoreductases are involved in the bioremediation by bacteria of azo dyes found in waste water. In the gut flora, they activate azo pro-drugs, which are used for treatment of inflammatory bowel disease, releasing the active component 5-aminosalycilic acid. The bacterium P. aeruginosa has three azoreductase genes, paAzoR1, paAzoR2 and paAzoR3, which as recombinant enzymes have been shown to have different substrate specificities. The mechanism of azoreduction relies upon tautomerisation of the substrate to the hydrazone form. We report here the characterization of the P. aeruginosa azoreductase enzymes, including determining their thermostability, cofactor preference and kinetic constants against a range of their favoured substrates. The expression levels of these enzymes during growth of P. aeruginosa are altered by the presence of azo substrates. It is shown that enzymes that were originally described as azoreductases, are likely to act as NADH quinone oxidoreductases. The low sequence identities observed among NAD(P)H quinone oxidoreductase and azoreductase enzymes suggests convergent evolution.
Collapse
Affiliation(s)
- Ali Ryan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | | | | | | | | |
Collapse
|
19
|
A novel mechanism for azoreduction. J Mol Biol 2010; 400:24-37. [PMID: 20417637 DOI: 10.1016/j.jmb.2010.04.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/12/2010] [Accepted: 04/13/2010] [Indexed: 11/20/2022]
Abstract
Azoreductases are important due to their ability to activate anti-inflammatory azo pro-drugs and to detoxify azo dyes. Three genes encoding azoreductases have been identified in Pseudomonas aeruginosa. We describe here a comparison of the three enzymes. The pure recombinant proteins each have a distinct substrate specificity profile against a range of azo substrates. Using the structure of P. aeruginosa azoreductase (paAzoR) 1 and the homology models of paAzoR2 and paAzoR3, we have identified residues important for substrate specificity. We have defined a novel flavin mononucleotide binding cradle, which is a recurrent motif in many flavodoxin-like proteins. A novel structure of paAzoR1 with the azo pro-drug balsalazide bound within the active site was determined by X-ray crystallography and demonstrates that the substrate is present in a hydrazone tautomer conformation. We propose that the structure with balsalazide bound represents an enzyme intermediate and, together with the flavin mononucleotide binding cradle, we propose a novel catalytic mechanism.
Collapse
|