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Wunderer M, Markt R, Lackner N, Wagner AO. The glutamyl tail length of the cofactor F 420 in the methanogenic Archaea Methanosarcina thermophila and Methanoculleus thermophilus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151112. [PMID: 34688753 DOI: 10.1016/j.scitotenv.2021.151112] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/01/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
The cofactor F420 is synthesized by many different organisms and as a redox cofactor, it plays a crucial role in the redox reactions of catabolic and biosynthetic metabolic pathways. It consists of a deazaflavin structure, which is linked via lactate to an oligoglutamate chain, that can vary in length. In the present study, the methanogenic Archaea Methanosarcina thermophila and Methanoculleus thermophilus were cultivated on different carbon sources and their coenzyme F420 composition has been assayed by reversed-phase ion-pair high-performance liquid chromatography with fluorometric detection regarding both, overall cofactor F420 production and distribution of F420 glutamyl tail length. In Methanosarcina thermophila cultivated on methanol, acetate, and a mixture of acetate and methanol, the most abundant cofactors were F420-5 and F420-4, whereby the last digit refers to the number of expressed glutamyl rests. By contrast, in the obligate CO2 reducing Methanoculleus thermophilus the most abundant cofactors were F420-3 and F420-4. In Methanosarcina thermophila, the relative proportions of the expressed F420 tail length changed during batch growth on all three carbon sources. Over time F420-3 and F420-4 decreased while F420-5 and F420-6 increased in their relative proportion in comparison to total F420 content. In contrast, in Methanoculleus thermophilus the relative abundance of the different F420 cofactors remained stable. It was also possible to differentiate the two methanogenic Archaea based on the glutamyl tail length of the cofactor F420. The cofactor F420-5 in concentrations >2% could only be assigned to Methanosarcina thermophila. In all four variants a trend for a positive correlation between the DNA concentration and the total concentration of the cofactor could be shown. Except for the variant Methanosarcinathermophila with acetate as sole carbon source the same could be shown between the concentration of the mcrA gene copy number and the total concentration of the cofactor.
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Affiliation(s)
- Mathias Wunderer
- Universität Innsbruck, Department of Microbiology, Technikerstraße 25d, 6020 Innsbruck, Austria.
| | - Rudolf Markt
- Universität Innsbruck, Department of Microbiology, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Nina Lackner
- Universität Innsbruck, Department of Microbiology, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Andreas O Wagner
- Universität Innsbruck, Department of Microbiology, Technikerstraße 25d, 6020 Innsbruck, Austria
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2
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Grinter R, Greening C. Cofactor F420: an expanded view of its distribution, biosynthesis and roles in bacteria and archaea. FEMS Microbiol Rev 2021; 45:fuab021. [PMID: 33851978 PMCID: PMC8498797 DOI: 10.1093/femsre/fuab021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/11/2021] [Indexed: 12/11/2022] Open
Abstract
Many bacteria and archaea produce the redox cofactor F420. F420 is structurally similar to the cofactors FAD and FMN but is catalytically more similar to NAD and NADP. These properties allow F420 to catalyze challenging redox reactions, including key steps in methanogenesis, antibiotic biosynthesis and xenobiotic biodegradation. In the last 5 years, there has been much progress in understanding its distribution, biosynthesis, role and applications. Whereas F420 was previously thought to be confined to Actinobacteria and Euryarchaeota, new evidence indicates it is synthesized across the bacterial and archaeal domains, as a result of extensive horizontal and vertical biosynthetic gene transfer. F420 was thought to be synthesized through one biosynthetic pathway; however, recent advances have revealed variants of this pathway and have resolved their key biosynthetic steps. In parallel, new F420-dependent biosynthetic and metabolic processes have been discovered. These advances have enabled the heterologous production of F420 and identified enantioselective F420H2-dependent reductases for biocatalysis. New research has also helped resolve how microorganisms use F420 to influence human and environmental health, providing opportunities for tuberculosis treatment and methane mitigation. A total of 50 years since its discovery, multiple paradigms associated with F420 have shifted, and new F420-dependent organisms and processes continue to be discovered.
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Affiliation(s)
- Rhys Grinter
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Chris Greening
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
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3
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Mutations in fbiD ( Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2020; 65:AAC.01948-20. [PMID: 33077652 DOI: 10.1128/aac.01948-20] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/07/2020] [Indexed: 11/20/2022] Open
Abstract
The nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10-5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.
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4
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Grinter R, Ney B, Brammananth R, Barlow CK, Cordero PRF, Gillett DL, Izoré T, Cryle MJ, Harold LK, Cook GM, Taiaroa G, Williamson DA, Warden AC, Oakeshott JG, Taylor MC, Crellin PK, Jackson CJ, Schittenhelm RB, Coppel RL, Greening C. Cellular and Structural Basis of Synthesis of the Unique Intermediate Dehydro-F 420-0 in Mycobacteria. mSystems 2020; 5:e00389-20. [PMID: 32430409 PMCID: PMC7253369 DOI: 10.1128/msystems.00389-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 11/29/2022] Open
Abstract
F420 is a low-potential redox cofactor used by diverse bacteria and archaea. In mycobacteria, this cofactor has multiple roles, including adaptation to redox stress, cell wall biosynthesis, and activation of the clinical antitubercular prodrugs pretomanid and delamanid. A recent biochemical study proposed a revised biosynthesis pathway for F420 in mycobacteria; it was suggested that phosphoenolpyruvate served as a metabolic precursor for this pathway, rather than 2-phospholactate as long proposed, but these findings were subsequently challenged. In this work, we combined metabolomic, genetic, and structural analyses to resolve these discrepancies and determine the basis of F420 biosynthesis in mycobacterial cells. We show that, in whole cells of Mycobacterium smegmatis, phosphoenolpyruvate rather than 2-phospholactate stimulates F420 biosynthesis. Analysis of F420 biosynthesis intermediates present in M. smegmatis cells harboring genetic deletions at each step of the biosynthetic pathway confirmed that phosphoenolpyruvate is then used to produce the novel precursor compound dehydro-F420-0. To determine the structural basis of dehydro-F420-0 production, we solved high-resolution crystal structures of the enzyme responsible (FbiA) in apo-, substrate-, and product-bound forms. These data show the essential role of a single divalent cation in coordinating the catalytic precomplex of this enzyme and demonstrate that dehydro-F420-0 synthesis occurs through a direct substrate transfer mechanism. Together, these findings resolve the biosynthetic pathway of F420 in mycobacteria and have significant implications for understanding the emergence of antitubercular prodrug resistance.IMPORTANCE Mycobacteria are major environmental microorganisms and cause many significant diseases, including tuberculosis. Mycobacteria make an unusual vitamin-like compound, F420, and use it to both persist during stress and resist antibiotic treatment. Understanding how mycobacteria make F420 is important, as this process can be targeted to create new drugs to combat infections like tuberculosis. In this study, we show that mycobacteria make F420 in a way that is different from other bacteria. We studied the molecular machinery that mycobacteria use to make F420, determining the chemical mechanism for this process and identifying a novel chemical intermediate. These findings also have clinical relevance, given that two new prodrugs for tuberculosis treatment are activated by F420.
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Affiliation(s)
- Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Blair Ney
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- CSIRO Land & Water, Canberra, ACT, Australia
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
| | - Rajini Brammananth
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Christopher K Barlow
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Monash Proteomics & Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Paul R F Cordero
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - David L Gillett
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Thierry Izoré
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Max J Cryle
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Liam K Harold
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - George Taiaroa
- Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Deborah A Williamson
- Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | | | | | | | - Paul K Crellin
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
| | - Ralf B Schittenhelm
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Monash Proteomics & Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Ross L Coppel
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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5
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Coenzyme F 420-Dependent Glucose-6-Phosphate Dehydrogenase-Coupled Polyglutamylation of Coenzyme F 420 in Mycobacteria. J Bacteriol 2018; 200:JB.00375-18. [PMID: 30249701 DOI: 10.1128/jb.00375-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/07/2018] [Indexed: 12/15/2022] Open
Abstract
Coenzyme F420 plays a key role in the redox metabolisms of various archaea and bacteria, including Mycobacterium tuberculosis In M. tuberculosis, F420-dependent reactions have been linked to several virulence factors. F420 carries multiple glutamate residues in the side chain, forming F420-n species (n, number of glutamate residues), and the length of this side chain impacts cellular physiology. M. tuberculosis strains with F420 species carrying shorter side chains exhibit resistance to delamanid and pretomanid, two new tuberculosis (TB) drugs. Thus, the process of polyglutamylation of F420 is of great interest. It has been known from genetic analysis that in mycobacteria an F420-0 γ-glutamyl ligase (FbiB) introduces up to seven glutamate residues into F420 However, purified FbiB of M. tuberculosis (MtbFbiB) is either inefficient or incapable of incorporating more than two glutamates. We found that, in vitro, MtbFbiB synthesized side chains containing up to seven glutamate residues if F420 was presented to the enzyme in a two-electron reduced state (F420H2). Our genetic analysis in Mycobacterium bovis BCG and Mycobacterium smegmatis and an analysis of literature data on M. tuberculosis revealed that in these mycobacteria the polyglutamylation process requires the assistance of F420-dependent glucose-6-phosphate dehydrogenase (Fgd) which reduces F420 to F420H2 We hypothesize that, starting with F420-0H2, the amino-terminal domain of FbiB builds F420-2H2, which is then transferred to the carboxy-terminal domain for further glutamylation; F420-2H2 modifies the carboxy-terminal domain structurally to accommodate longer glutamyl chains. This system is analogous to folylpolyglutamate synthase, which introduces more than one glutamate residue into folate only after this vitamin is reduced to tetrahydrofolate.IMPORTANCE Coenzyme F420-dependent reactions of Mycobacterium tuberculosis, which causes tuberculosis, potentially contributes to the virulence of this bacterium. The coenzyme carries a glutamic acid-derived tail, the length of which influences the metabolism of M. tuberculosis Mutations that eliminate the production of F420 with longer tails make M. tuberculosis resistant to two new tuberculosis drugs. This report describes that the synthesis of longer glutamyl tails of F420 requires concerted actions of two enzymes, one of which reduces the coenzyme prior to the action of the other, which catalyzes polyglutamylation. This knowledge will help to develop more effective tuberculosis (TB) drugs. Remarkably, the introduction of multiple glutamate residues into the sidechain of folate (vitamin B9) requires similar concerted actions, where one enzyme reduces the vitamin to tetrahydrofolate and the other catalyzes polyglutamylation; folate is required for DNA and amino acid synthesis. Thus, the reported research has also revealed a key similarity between two important cellular systems.
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6
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Trousil J, Ulmann V, Hrubý M. Fluorescence & bioluminescence in the quest for imaging, probing & analysis of mycobacterial infections. Future Microbiol 2018; 13:933-951. [PMID: 29893148 DOI: 10.2217/fmb-2017-0296] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacterioses represent a global health problem and rapid diagnostic improvements are urgently required. Mycobacteria-specific fluorescence and bioluminescence phenomena have been found to be useful for a wide range of mycobacteria-focused research. Here, we present a critical survey of the most promising techniques in this field and the potential of new methods under investigation. These approaches include acid-fast staining, intrinsic fluorescence of the coenzyme F420, fluorogenic substrates (e.g., β-lactamase-sensitive coumpounds) and recombination of mycobacteria or mycobacteriophages. Probably the most interesting and emerging host-inspecting approach is in vivo imaging. Detection of fluorescence in vivo, however, is complicated by light scattering, light absorption, and autofluorescence, caused by the tissues. Despite this, many of these systems show promise as the foundations for improved rapid analysis and imaging of mycobacterial infections, both in vitro and in vivo.
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Affiliation(s)
- Jiří Trousil
- Department of Supramolecular Polymer Systems, Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského náměstí 2, 162 06 Prague 6, Czech Republic.,Department of Analytical Chemistry, Charles University, Faculty of Science, Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Vít Ulmann
- Laboratory for Mycobacterial Diagnostics and Tuberculosis, Regional Institute of Public Health in Ostrava, Partyzánské náměstí 7, 702 00 Ostrava, Czech Republic
| | - Martin Hrubý
- Department of Supramolecular Polymer Systems, Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského náměstí 2, 162 06 Prague 6, Czech Republic
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7
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Papadopoulou MV, Bloomer WD, Rosenzweig HS. The antitubercular activity of various nitro(triazole/imidazole)-based compounds. Bioorg Med Chem 2017; 25:6039-6048. [DOI: 10.1016/j.bmc.2017.09.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/17/2017] [Accepted: 09/24/2017] [Indexed: 02/04/2023]
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8
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Ney B, Carere CR, Sparling R, Jirapanjawat T, Stott MB, Jackson CJ, Oakeshott JG, Warden AC, Greening C. Cofactor Tail Length Modulates Catalysis of Bacterial F 420-Dependent Oxidoreductases. Front Microbiol 2017; 8:1902. [PMID: 29021791 PMCID: PMC5623714 DOI: 10.3389/fmicb.2017.01902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/15/2017] [Indexed: 11/13/2022] Open
Abstract
F420 is a microbial cofactor that mediates a wide range of physiologically important and industrially relevant redox reactions, including in methanogenesis and tetracycline biosynthesis. This deazaflavin comprises a redox-active isoalloxazine headgroup conjugated to a lactyloligoglutamyl tail. Here we studied the catalytic significance of the oligoglutamate chain, which differs in length between bacteria and archaea. We purified short-chain F420 (two glutamates) from a methanogen isolate and long-chain F420 (five to eight glutamates) from a recombinant mycobacterium, confirming their different chain lengths by HPLC and LC/MS analysis. F420 purified from both sources was catalytically compatible with purified enzymes from the three major bacterial families of F420-dependent oxidoreductases. However, long-chain F420 bound to these enzymes with a six- to ten-fold higher affinity than short-chain F420. The cofactor side chain also significantly modulated the kinetics of the enzymes, with long-chain F420 increasing the substrate affinity (lower Km) but reducing the turnover rate (lower kcat) of the enzymes. Molecular dynamics simulations and comparative structural analysis suggest that the oligoglutamate chain of F420 makes dynamic electrostatic interactions with conserved surface residues of the oxidoreductases while the headgroup binds the catalytic site. In conjunction with the kinetic data, this suggests that electrostatic interactions made by the oligoglutamate tail result in higher-affinity, lower-turnover catalysis. Physiologically, we propose that bacteria have selected for long-chain F420 to better control cellular redox reactions despite tradeoffs in catalytic rate. Conversely, this suggests that industrial use of shorter-length F420 will greatly increase the rates of bioremediation and biocatalysis processes relying on purified F420-dependent oxidoreductases.
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Affiliation(s)
- Blair Ney
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Carlo R Carere
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand
| | - Richard Sparling
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand.,Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | | | - Matthew B Stott
- GNS Science, Wairakei Research Centre, Lower Hutt, New Zealand
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Acton, ACT, Australia
| | - John G Oakeshott
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Andrew C Warden
- Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.,Land and Water Flagship, The Commonwealth Scientific and Industrial Research Organisation, Acton, ACT, Australia
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9
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Kumar H, Nguyen QT, Binda C, Mattevi A, Fraaije MW. Isolation and characterization of a thermostable F 420:NADPH oxidoreductase from Thermobifida fusca. J Biol Chem 2017; 292:10123-10130. [PMID: 28411200 DOI: 10.1074/jbc.m117.787754] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 04/07/2017] [Indexed: 12/23/2022] Open
Abstract
F420H2-dependent enzymes reduce a wide range of substrates that are otherwise recalcitrant to enzyme-catalyzed reduction, and their potential for applications in biocatalysis has attracted increasing attention. Thermobifida fusca is a moderately thermophilic bacterium and holds high biocatalytic potential as a source for several highly thermostable enzymes. We report here on the isolation and characterization of a thermostable F420: NADPH oxidoreductase (Tfu-FNO) from T. fusca, the first F420-dependent enzyme described from this bacterium. Tfu-FNO was heterologously expressed in Escherichia coli, yielding up to 200 mg of recombinant enzyme per liter of culture. We found that Tfu-FNO is highly thermostable, reaching its highest activity at 65 °C and that Tfu-FNO is likely to act in vivo as an F420 reductase at the expense of NADPH, similar to its counterpart in Streptomyces griseus We obtained the crystal structure of FNO in complex with NADP+ at 1.8 Å resolution, providing the first bacterial FNO structure. The overall architecture and NADP+-binding site of Tfu-FNO were highly similar to those of the Archaeoglobus fulgidus FNO (Af-FNO). The active site is located in a hydrophobic pocket between an N-terminal dinucleotide binding domain and a smaller C-terminal domain. Residues interacting with the 2'-phosphate of NADP+ were probed by targeted mutagenesis, indicating that Thr-28, Ser-50, Arg-51, and Arg-55 are important for discriminating between NADP+ and NAD+ Interestingly, a T28A mutant increased the kinetic efficiency >3-fold as compared with the wild-type enzyme when NADH is the substrate. The biochemical and structural data presented here provide crucial insights into the molecular recognition of the two cofactors, F420 and NAD(P)H by FNO.
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Affiliation(s)
- Hemant Kumar
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Quoc-Thai Nguyen
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Scuola Universitaria Superiore IUSS Pavia, Piazza della Vittoria 15, 27100 Pavia, Italy.,Faculty of Pharmacy, University of Medicine and Pharmacy, Ho Chi Minh City, 41 Dinh Tien Hoang St., Ben Nghe Ward, District 1, Ho Chi Minh City, Vietnam, and
| | - Claudia Binda
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Andrea Mattevi
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Marco W Fraaije
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands,
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10
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Wong C, Ha NP, Pawlowski ME, Graviss EA, Tkaczyk TS. Differentiating between live and dead Mycobacterium smegmatis using autofluorescence. Tuberculosis (Edinb) 2016; 101S:S119-S123. [PMID: 27742463 DOI: 10.1016/j.tube.2016.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
While there have been research efforts to find faster and more efficient diagnostic techniques for tuberculosis (TB), it is equally important to monitor a patient's response to treatment over time, especially with the increasing prevalence of multi-drug resistant (MDR) and extensively-drug resistant (XDR) TB. Between sputum smear microscopy, culture, and GeneXpert, only culture can verify viability of mycobacteria. However, it may take up to six weeks to grow Mycobacterium tuberculosis (Mtb), during which time the patient may have responded to treatment or the mycobacteria are still viable because the patient has MDR or XDR TB. In both situations, treatment incurs increased patient costs and makes them more susceptible to host-drug effects such as liver damage. Coenzyme Factor 420 (F420) is a fluorescent coenzyme found naturally in mycobacteria, with an excitation peak around 420 nm and an emission peak around 470 nm. Using Mycobacterium smegmatis, we show that live and dead mycobacteria undergo different rates of photobleaching over a period of 2 min. These preliminary experiments suggest that the different photobleaching rates could be used to help monitor a patient's response to TB treatment. In future studies, we propose to describe these experiments with Mtb as both M. smegmatis and Mtb use F420.
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Affiliation(s)
- Cynthia Wong
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77005, United States.
| | - Ngan P Ha
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX 77030, United States.
| | - Michal E Pawlowski
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77005, United States.
| | - Edward A Graviss
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX 77030, United States.
| | - Tomasz S Tkaczyk
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77005, United States; Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States.
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11
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Ney B, Ahmed FH, Carere CR, Biswas A, Warden AC, Morales SE, Pandey G, Watt SJ, Oakeshott JG, Taylor MC, Stott MB, Jackson CJ, Greening C. The methanogenic redox cofactor F 420 is widely synthesized by aerobic soil bacteria. ISME JOURNAL 2016; 11:125-137. [PMID: 27505347 DOI: 10.1038/ismej.2016.100] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/07/2016] [Accepted: 06/13/2016] [Indexed: 02/07/2023]
Abstract
F420 is a low-potential redox cofactor that mediates the transformations of a wide range of complex organic compounds. Considered one of the rarest cofactors in biology, F420 is best known for its role in methanogenesis and has only been chemically identified in two phyla to date, the Euryarchaeota and Actinobacteria. In this work, we show that this cofactor is more widely distributed than previously reported. We detected the genes encoding all five known F420 biosynthesis enzymes (cofC, cofD, cofE, cofG and cofH) in at least 653 bacterial and 173 archaeal species, including members of the dominant soil phyla Proteobacteria, Chloroflexi and Firmicutes. Metagenome datamining validated that these genes were disproportionately abundant in aerated soils compared with other ecosystems. We confirmed through high-performance liquid chromatography analysis that aerobically grown stationary-phase cultures of three bacterial species, Paracoccus denitrificans, Oligotropha carboxidovorans and Thermomicrobium roseum, synthesized F420, with oligoglutamate sidechains of different lengths. To understand the evolution of F420 biosynthesis, we also analyzed the distribution, phylogeny and genetic organization of the cof genes. Our data suggest that although the Fo precursor to F420 originated in methanogens, F420 itself was first synthesized in an ancestral actinobacterium. F420 biosynthesis genes were then disseminated horizontally to archaea and other bacteria. Together, our findings suggest that the cofactor is more significant in aerobic bacterial metabolism and soil ecosystem composition than previously thought. The cofactor may confer several competitive advantages for aerobic soil bacteria by mediating their central metabolic processes and broadening the range of organic compounds they can synthesize, detoxify and mineralize.
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Affiliation(s)
- Blair Ney
- Research School of Chemistry, Australian National University, Acton, Australian Capital Territory, Australia.,The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
| | - F Hafna Ahmed
- Research School of Chemistry, Australian National University, Acton, Australian Capital Territory, Australia
| | - Carlo R Carere
- GNS Science, Wairakei Research Centre, Taupō, New Zealand
| | - Ambarish Biswas
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Andrew C Warden
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
| | - Sergio E Morales
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Gunjan Pandey
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
| | - Stephen J Watt
- Research School of Chemistry, Australian National University, Acton, Australian Capital Territory, Australia
| | - John G Oakeshott
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
| | - Matthew C Taylor
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
| | | | - Colin J Jackson
- Research School of Chemistry, Australian National University, Acton, Australian Capital Territory, Australia
| | - Chris Greening
- The Commonwealth Scientific and Industrial Research Organisation, Land and Water, Acton, Australian Capital Territory, Australia
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12
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Physiology, Biochemistry, and Applications of F420- and Fo-Dependent Redox Reactions. Microbiol Mol Biol Rev 2016; 80:451-93. [PMID: 27122598 DOI: 10.1128/mmbr.00070-15] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
5-Deazaflavin cofactors enhance the metabolic flexibility of microorganisms by catalyzing a wide range of challenging enzymatic redox reactions. While structurally similar to riboflavin, 5-deazaflavins have distinctive and biologically useful electrochemical and photochemical properties as a result of the substitution of N-5 of the isoalloxazine ring for a carbon. 8-Hydroxy-5-deazaflavin (Fo) appears to be used for a single function: as a light-harvesting chromophore for DNA photolyases across the three domains of life. In contrast, its oligoglutamyl derivative F420 is a taxonomically restricted but functionally versatile cofactor that facilitates many low-potential two-electron redox reactions. It serves as an essential catabolic cofactor in methanogenic, sulfate-reducing, and likely methanotrophic archaea. It also transforms a wide range of exogenous substrates and endogenous metabolites in aerobic actinobacteria, for example mycobacteria and streptomycetes. In this review, we discuss the physiological roles of F420 in microorganisms and the biochemistry of the various oxidoreductases that mediate these roles. Particular focus is placed on the central roles of F420 in methanogenic archaea in processes such as substrate oxidation, C1 pathways, respiration, and oxygen detoxification. We also describe how two F420-dependent oxidoreductase superfamilies mediate many environmentally and medically important reactions in bacteria, including biosynthesis of tetracycline and pyrrolobenzodiazepine antibiotics by streptomycetes, activation of the prodrugs pretomanid and delamanid by Mycobacterium tuberculosis, and degradation of environmental contaminants such as picrate, aflatoxin, and malachite green. The biosynthesis pathways of Fo and F420 are also detailed. We conclude by considering opportunities to exploit deazaflavin-dependent processes in tuberculosis treatment, methane mitigation, bioremediation, and industrial biocatalysis.
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13
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Bashiri G, Rehan AM, Sreebhavan S, Baker HM, Baker EN, Squire CJ. Elongation of the Poly-γ-glutamate Tail of F420 Requires Both Domains of the F420:γ-Glutamyl Ligase (FbiB) of Mycobacterium tuberculosis. J Biol Chem 2016; 291:6882-94. [PMID: 26861878 DOI: 10.1074/jbc.m115.689026] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Indexed: 01/21/2023] Open
Abstract
Cofactor F420is an electron carrier with a major role in the oxidoreductive reactions ofMycobacterium tuberculosis, the causative agent of tuberculosis. A γ-glutamyl ligase catalyzes the final steps of the F420biosynthesis pathway by successive additions ofl-glutamate residues to F420-0, producing a poly-γ-glutamate tail. The enzyme responsible for this reaction in archaea (CofE) comprises a single domain and produces F420-2 as the major species. The homologousM. tuberculosisenzyme, FbiB, is a two-domain protein and produces F420with predominantly 5-7l-glutamate residues in the poly-γ-glutamate tail. The N-terminal domain of FbiB is homologous to CofE with an annotated γ-glutamyl ligase activity, whereas the C-terminal domain has sequence similarity to an FMN-dependent family of nitroreductase enzymes. Here we demonstrate that full-length FbiB adds multiplel-glutamate residues to F420-0in vitroto produce F420-5 after 24 h; communication between the two domains is critical for full γ-glutamyl ligase activity. We also present crystal structures of the C-terminal domain of FbiB in apo-, F420-0-, and FMN-bound states, displaying distinct sites for F420-0 and FMN ligands that partially overlap. Finally, we discuss the features of a full-length structural model produced by small angle x-ray scattering and its implications for the role of N- and C-terminal domains in catalysis.
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Affiliation(s)
- Ghader Bashiri
- From the Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, and
| | - Aisyah M Rehan
- From the Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, and
| | - Sreevalsan Sreebhavan
- the Faculty of Medical and Health Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Heather M Baker
- From the Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, and
| | - Edward N Baker
- From the Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, and
| | - Christopher J Squire
- From the Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, and
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14
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Mashalidis EH, Gittis AG, Tomczak A, Abell C, Barry CE, Garboczi DN. Molecular insights into the binding of coenzyme F420 to the conserved protein Rv1155 from Mycobacterium tuberculosis. Protein Sci 2015; 24:729-40. [PMID: 25644473 DOI: 10.1002/pro.2645] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/17/2015] [Accepted: 01/20/2015] [Indexed: 01/01/2023]
Abstract
Coenzyme F420 is a deazaflavin hydride carrier with a lower reduction potential than most flavins. In Mycobacterium tuberculosis (Mtb), F420 plays an important role in activating PA-824, an antituberculosis drug currently used in clinical trials. Although F420 is important to Mtb redox metabolism, little is known about the enzymes that bind F420 and the reactions that they catalyze. We have identified a novel F420 -binding protein, Rv1155, which is annotated in the Mtb genome sequence as a putative flavin mononucleotide (FMN)-binding protein. Using biophysical techniques, we have demonstrated that instead of binding FMN or other flavins, Rv1155 binds coenzyme F420 . The crystal structure of the complex of Rv1155 and F420 reveals one F420 molecule bound to each monomer of the Rv1155 dimer. Structural, biophysical, and bioinformatic analyses of the Rv1155-F420 complex provide clues about its role in the bacterium.
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Affiliation(s)
- Ellene H Mashalidis
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, 20892; Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom
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15
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Single-cell tracking reveals antibiotic-induced changes in mycobacterial energy metabolism. mBio 2015; 6:e02236-14. [PMID: 25691591 PMCID: PMC4338811 DOI: 10.1128/mbio.02236-14] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ATP is a key molecule of cell physiology, but despite its importance, there are currently no methods for monitoring single-cell ATP fluctuations in live bacteria. This is a major obstacle in studies of bacterial energy metabolism, because there is a growing awareness that bacteria respond to stressors such as antibiotics in a highly individualistic manner. Here, we present a method for long-term single-cell tracking of ATP levels in Mycobacterium smegmatis based on a combination of microfluidics, time-lapse microscopy, and Förster resonance energy transfer (FRET)-based ATP biosensors. Upon treating cells with antibiotics, we observed that individual cells undergo an abrupt and irreversible switch from high to low intracellular ATP levels. The kinetics and extent of ATP switching clearly discriminate between an inhibitor of ATP synthesis and other classes of antibiotics. Cells that resume growth after 24 h of antibiotic treatment maintain high ATP levels throughout the exposure period. In contrast, antibiotic-treated cells that switch from ATP-high to ATP-low states never resume growth after antibiotic washout. Surprisingly, only a subset of these nongrowing ATP-low cells stains with propidium iodide (PI), a widely used live/dead cell marker. These experiments also reveal a cryptic subset of cells that do not resume growth after antibiotic washout despite remaining ATP high and PI negative. We conclude that ATP tracking is a more dynamic, sensitive, reliable, and discriminating marker of cell viability than staining with PI. This method could be used in studies to evaluate antimicrobial effectiveness and mechanism of action, as well as for high-throughput screening. New antimicrobials are urgently needed to stem the rising tide of antibiotic-resistant bacteria. All antibiotics are expected to affect bacterial energy metabolism, directly or indirectly, yet tools to assess the impact of antibiotics on the ATP content of individual bacterial cells are lacking. The method described here for single-cell tracking of intracellular ATP in live bacteria has many advantages compared to conventional ensemble-averaged assays. It provides a continuous real-time readout of bacterial ATP content, cell vitality, and antimicrobial mechanism of action with high temporal resolution at the single-cell level. In combination with high-throughput microfluidic devices and automated microscopy, this method also has the potential to serve as a novel screening tool in antimicrobial drug discovery.
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16
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Lanz ND, Booker SJ. Auxiliary iron-sulfur cofactors in radical SAM enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1316-34. [PMID: 25597998 DOI: 10.1016/j.bbamcr.2015.01.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/15/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022]
Abstract
A vast number of enzymes are now known to belong to a superfamily known as radical SAM, which all contain a [4Fe-4S] cluster ligated by three cysteine residues. The remaining, unligated, iron ion of the cluster binds in contact with the α-amino and α-carboxylate groups of S-adenosyl-l-methionine (SAM). This binding mode facilitates inner-sphere electron transfer from the reduced form of the cluster into the sulfur atom of SAM, resulting in a reductive cleavage of SAM to methionine and a 5'-deoxyadenosyl radical. The 5'-deoxyadenosyl radical then abstracts a target substrate hydrogen atom, initiating a wide variety of radical-based transformations. A subset of radical SAM enzymes contains one or more additional iron-sulfur clusters that are required for the reactions they catalyze. However, outside of a subset of sulfur insertion reactions, very little is known about the roles of these additional clusters. This review will highlight the most recent advances in the identification and characterization of radical SAM enzymes that harbor auxiliary iron-sulfur clusters. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Nicholas D Lanz
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
| | - Squire J Booker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States; Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States.
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17
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Wang Y, Xu H, Harich KC, White RH. Identification and Characterization of a Tyramine–Glutamate Ligase (MfnD) Involved in Methanofuran Biosynthesis. Biochemistry 2014; 53:6220-30. [DOI: 10.1021/bi500879h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Yu Wang
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Huimin Xu
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Kim C. Harich
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Robert H. White
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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18
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Allen KD, White RH. Identification of structurally diverse methanofuran coenzymes in methanococcales that are both N-formylated and N-acetylated. Biochemistry 2014; 53:6199-210. [PMID: 25203397 DOI: 10.1021/bi500973h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Methanofuran (MF) is a coenzyme necessary for the first step of methanogenesis from CO2. The well-characterized MF core structure is 4-[N-(γ-l-glutamyl-γ-l-glutamyl)-p-(β-aminoethyl)phenoxymethyl]-2-(aminomethyl)furan (APMF-γ-Glu2). Three different MF structures that differ on the basis of the composition of their side chains have been determined previously. Here, we use liquid chromatography coupled with high-resolution mass spectrometry and a variety of biochemical methods to deduce the unique structures of MFs present in four different methanogens in the order Methanococcales. This is the first detailed characterization of the MF occurring in methanogens of this order. MF in each of these organisms contains the expected APMF-γ-Glu2; however, the composition of the side chain is different from that of the previously described MF structures. In Methanocaldococcus jannaschii, additional γ-linked glutamates that range from 7 to 12 residues are present. The MF coenzymes in Methanococcus maripaludis, Methanococcus vannielii, and Methanothermococcus okinawensis also have additional glutamate residues but interestingly also contain a completely different chemical moiety in the middle of the side chain that we have identified as N-(3-carboxy-2- or 3-hydroxy-1-oxopropyl)-l-aspartic acid. This addition results in the terminal γ-linked glutamates being incorporated in the opposite orientation. In addition to these nonacylated MF coenzymes, we also identified the corresponding N-formyl-MF and, surprisingly, N-acetyl-MF derivatives. N-Acetyl-MF has never been observed or implied to be functioning in nature and may represent a new route for acetate formation in methanogens.
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Affiliation(s)
- Kylie D Allen
- Department of Biochemistry, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061-0308, United States
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19
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Nitrotriazole- and imidazole-based amides and sulfonamides as antitubercular agents. Antimicrob Agents Chemother 2014; 58:6828-36. [PMID: 25182645 DOI: 10.1128/aac.03644-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Twenty-three 3-nitrotriazole-based and 2-nitroimidazole-based amides and sulfonamides were screened for antitubercular (anti-TB) activity in aerobic Mycobacterium tuberculosis H37Rv by using the BacTiter-Glo (BTG) microbial cell viability assay. In general, 3-nitrotriazole-based sulfonamides demonstrated anti-TB activity, whereas 3-nitrotriazole-based amides and 2-nitroimidazole-based amides and sulfonamides were inactive. Three 3-nitrotriazole-based sulfonamides (compounds 4, 2, and 7) demonstrated 50% inhibitory concentration (IC50), IC90, and MIC values of 0.38, 0.43, and 1.56 μM (compound 4), 0.57, 0.98, and 3.13 μM (compound 2), and 0.79, 0.87, and 3.13 μM (compound 7), respectively. For 3-nitrotriazole-based sulfonamides, anti-TB activity increased with lipophilicity, whereas the one-electron reduction potential (E1/2) did not play a role. 2-Nitroimidazole-based analogs, which were inactive in the BTG assay, were significantly more active in the low-oxygen assay and more active than the 3-nitrotriazoles. All active nitrotriazoles in the BTG assay were similarly active or more potent (lower MIC values) against resistant strains, with the exception of compounds 2, 3, 4, and 8, which demonstrated greater MIC values against isoniazid-resistant strains. Five 3-nitrotriazole-based sulfonamides demonstrated activity in infected murine J774 macrophages, causing log reductions similar to those seen with rifampin. However, some compounds caused toxicity in uninfected macrophages. In conclusion, the classes of 3-nitrotriazole-based amides and sulfonamides merit further investigation as potential antitubercular agents.
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20
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Mechanism of action of 5-nitrothiophenes against Mycobacterium tuberculosis. Antimicrob Agents Chemother 2014; 58:2944-7. [PMID: 24550336 DOI: 10.1128/aac.02693-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
On using the streptomycin-starved 18b strain as a model for nonreplicating Mycobacterium tuberculosis, we identified a 5-nitrothiophene compound as highly active but not cytotoxic. Mutants resistant to 5-nitrothiophenes were found be cross-resistant to the nitroimidazole PA-824 and unable to produce the F420 cofactor. Furthermore, 5-nitrothiophenes were shown to be activated by the F420-dependent nitroreductase Ddn and to release nitric oxide, a mechanism of action identical to that described for nitroimidazoles.
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21
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Kritsky MS, Telegina TA, Vechtomova YL, Buglak AA. Why flavins are not competitors of chlorophyll in the evolution of biological converters of solar energy. Int J Mol Sci 2012; 14:575-93. [PMID: 23271372 PMCID: PMC3565283 DOI: 10.3390/ijms14010575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/10/2012] [Accepted: 12/13/2012] [Indexed: 12/17/2022] Open
Abstract
Excited flavin molecules can photocatalyze reactions, leading to the accumulation of free energy in the products, and the data accumulated through biochemical experiments and by modeling prebiological processes suggest that flavins were available in the earliest stages of evolution. Furthermore, model experiments have shown that abiogenic flavin conjugated with a polyamino acid matrix, a pigment that photocatalyzes the phosphorylation of ADP to form ATP, could have been present in the prebiotic environment. Indeed, excited flavin molecules play key roles in many photoenzymes and regulatory photoreceptors, and the substantial structural differences between photoreceptor families indicate that evolution has repeatedly used flavins as chromophores for photoreceptor proteins. Some of these photoreceptors are equipped with a light-harvesting antenna, which transfers excitation energy to chemically reactive flavins in the reaction center. The sum of the available data suggests that evolution could have led to the formation of a flavin-based biological converter to convert light energy into energy in the form of ATP.
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Affiliation(s)
- Mikhail S. Kritsky
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, House 33, Building 2, Leninsky Prospekt, Moscow 119071, Russia; E-Mails: (T.A.T.); (Y.L.V.); (A.A.B.)
| | - Taisiya A. Telegina
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, House 33, Building 2, Leninsky Prospekt, Moscow 119071, Russia; E-Mails: (T.A.T.); (Y.L.V.); (A.A.B.)
| | - Yulia L. Vechtomova
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, House 33, Building 2, Leninsky Prospekt, Moscow 119071, Russia; E-Mails: (T.A.T.); (Y.L.V.); (A.A.B.)
| | - Andrey A. Buglak
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, House 33, Building 2, Leninsky Prospekt, Moscow 119071, Russia; E-Mails: (T.A.T.); (Y.L.V.); (A.A.B.)
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22
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Decamps L, Philmus B, Benjdia A, White R, Begley TP, Berteau O. Biosynthesis of F0, Precursor of the F420 Cofactor, Requires a Unique Two Radical-SAM Domain Enzyme and Tyrosine as Substrate. J Am Chem Soc 2012; 134:18173-6. [DOI: 10.1021/ja307762b] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Laure Decamps
- Institut National de la Recherche Agronomique, UMR 1319 Micalis, F-78350
Jouy-en-Josas, France
- AgroParisTech, UMR Micalis, F-78350 Jouy-en-Josas,
France
| | - Benjamin Philmus
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Alhosna Benjdia
- Department
of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse
29, 69120 Heidelberg, Germany
| | - Robert White
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United
States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Olivier Berteau
- Institut National de la Recherche Agronomique, UMR 1319 Micalis, F-78350
Jouy-en-Josas, France
- AgroParisTech, UMR Micalis, F-78350 Jouy-en-Josas,
France
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23
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Bandarian V. Radical SAM enzymes involved in the biosynthesis of purine-based natural products. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:1245-53. [PMID: 22902275 DOI: 10.1016/j.bbapap.2012.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 07/21/2012] [Accepted: 07/26/2012] [Indexed: 12/19/2022]
Abstract
The radical S-adenosyl-l-methionine (SAM) superfamily is a widely distributed group of iron-sulfur containing proteins that exploit the reactivity of the high energy intermediate, 5'-deoxyadenosyl radical, which is produced by the reductive cleavage of SAM, to carry-out complex radical-mediated transformations. The reactions catalyzed by radical SAM enzymes range from simple group migrations to complex reactions in protein and RNA modification. This review will highlight three radical SAM enzymes that catalyze reactions involving modified guanosines in the biosynthesis pathways of the hypermodified tRNA base wybutosine; secondary metabolites of 7-deazapurine structure, including the hypermodified tRNA base queuosine; and the redox cofactor F(420). This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology.
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Affiliation(s)
- Vahe Bandarian
- University of Arizona, Department of Chemistry and Biochemistry, 1041 E. Lowell St., Tucson, AZ 85721‐0088, USA.
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24
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Cellitti SE, Shaffer J, Jones DH, Mukherjee T, Gurumurthy M, Bursulaya B, Boshoff HI, Choi I, Nayyar A, Lee YS, Cherian J, Niyomrattanakit P, Dick T, Manjunatha UH, Barry CE, Spraggon G, Geierstanger BH. Structure of Ddn, the deazaflavin-dependent nitroreductase from Mycobacterium tuberculosis involved in bioreductive activation of PA-824. Structure 2012; 20:101-12. [PMID: 22244759 PMCID: PMC3267046 DOI: 10.1016/j.str.2011.11.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 11/01/2011] [Accepted: 11/01/2011] [Indexed: 11/29/2022]
Abstract
Tuberculosis continues to be a global health threat, making bicyclic nitroimidazoles an important new class of therapeutics. A deazaflavin-dependent nitroreductase (Ddn) from Mycobacterium tuberculosis catalyzes the reduction of nitroimidazoles such as PA-824, resulting in intracellular release of lethal reactive nitrogen species. The N-terminal 30 residues of Ddn are functionally important but are flexible or access multiple conformations, preventing structural characterization of the full-length, enzymatically active enzyme. Several structures were determined of a truncated, inactive Ddn protein core with and without bound F420 deazaflavin coenzyme as well as of a catalytically competent homolog from Nocardia farcinica. Mutagenesis studies based on these structures identified residues important for binding of F420 and PA-824. The proposed orientation of the tail of PA-824 toward the N terminus of Ddn is consistent with current structure-activity relationship data.
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Affiliation(s)
- Susan E Cellitti
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121-1125, USA
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25
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Joshi P, Singh M, Bhargava A, Singh M, Mehrotra R. Autofluorescence--an important ancillary technique for the detection of Mycobacterium tuberculosis: revisited. Diagn Cytopathol 2012; 41:330-4. [PMID: 22351040 DOI: 10.1002/dc.21860] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 09/13/2011] [Indexed: 11/10/2022]
Abstract
Tuberculosis is one of the oldest diseases known to affect humans and is caused by Mycobacterium tuberculosis. Lymph nodes are the most common site of extrapulmonary involvement. Tuberculous lymphadenitis can be presumptively diagnosed morphologically on fine-needle aspiration biopsy of lymph nodes. Additional tests like Ziehl-Neelsen (ZN) stain for detection of acid fast bacilli, fluorescence, and molecular markers are often employed for confirmation of diagnosis. However, culture is essential for obtaining a definitive diagnosis. Unfortunately, culture is time consuming and expensive. Newer investigative methods are required. The efficacy of autofluorescence in the diagnosis of tuberculous lymphadenitis was evaluated for this purpose. Fine-needle aspiration biopsies were collected from patients with a clinical diagnosis of tuberculous lymphadenitis. Cytomorphological examination, ZN staining, autofluorescence, and culture were performed on all specimens. ZN staining was positive in 37.5% (30/80) of cases, while autofluorescence was positive in 57.5% (46/80) of patients and was found to have 81.8% specificity, 95% sensitivity, and a positive predictive value of 82.6%. This technique allowed rapid and early diagnosis of tuberculous lymphadenitis in a number of patients, permitting early institution of appropriate therapy.
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Affiliation(s)
- Parul Joshi
- Department of Pathology, Moti Lal Nehru Medical College, Allahabad, India
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26
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Gurumurthy M, Mukherjee T, Dowd CS, Singh R, Niyomrattanakit P, Tay JA, Nayyar A, Lee YS, Cherian J, Boshoff HI, Dick T, Barry CE, Manjunatha UH. Substrate specificity of the deazaflavin-dependent nitroreductase from Mycobacterium tuberculosis responsible for the bioreductive activation of bicyclic nitroimidazoles. FEBS J 2012; 279:113-25. [PMID: 22023140 PMCID: PMC3444742 DOI: 10.1111/j.1742-4658.2011.08404.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The bicyclic 4-nitroimidazoles PA-824 and OPC-67683 represent a promising novel class of therapeutics for tuberculosis and are currently in phase II clinical development. Both compounds are pro-drugs that are reductively activated by a deazaflavin (F(420)) dependent nitroreductase (Ddn). Herein we describe the biochemical properties of Ddn including the optimal enzymatic turnover conditions and substrate specificity. The preference of the enzyme for the (S) isomer of PA-824 over the (R) isomer is directed by the presence of a long hydrophobic tail. Nitroimidazo-oxazoles bearing only short alkyl substituents at the C-7 position of the oxazole were reduced by Ddn without any stereochemical preference. However, with bulkier substitutions on the tail of the oxazole, Ddn displayed stereospecificity. Ddn mediated metabolism of PA-824 results in the release of reactive nitrogen species. We have employed a direct chemiluminescence based nitric oxide (NO) detection assay to measure the kinetics of NO production by Ddn. Binding affinity of PA-824 to Ddn was monitored through intrinsic fluorescence quenching of the protein facilitating a turnover-independent assessment of affinity. Our results indicate that (R)-PA-824, despite not being turned over by Ddn, binds to the enzyme with the same affinity as the active (S) isomer. This result, in combination with docking studies in the active site, suggests that the (R) isomer probably has a different binding mode than the (S) with the C-3 of the imidazole ring orienting in a non-productive position with respect to the incoming hydride from F(420). The results presented provide insight into the biochemical mechanism of reduction and elucidate structural features important for understanding substrate binding.
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Affiliation(s)
- Meera Gurumurthy
- Novartis Institute for Tropical Diseases (NITD), Singapore-138670
| | | | | | | | | | - Jo Ann Tay
- Novartis Institute for Tropical Diseases (NITD), Singapore-138670
| | - Amit Nayyar
- Tuberculosis Research Section, NIH, Bethesda- 20892, USA
| | - Yong Sok Lee
- Center for Molecular Modeling, Center for Information Technology, NIH, Bethesda- 20892, USA
| | - Joseph Cherian
- Novartis Institute for Tropical Diseases (NITD), Singapore-138670
| | | | - Thomas Dick
- Novartis Institute for Tropical Diseases (NITD), Singapore-138670
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27
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Rehan AM, Bashiri G, Paterson NG, Baker EN, Squire CJ. Cloning, expression, purification, crystallization and preliminary X-ray studies of the C-terminal domain of Rv3262 (FbiB) from Mycobacterium tuberculosis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1274-7. [PMID: 22102046 PMCID: PMC3212381 DOI: 10.1107/s1744309111028958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 07/18/2011] [Indexed: 11/11/2022]
Abstract
During cofactor F(420) biosynthesis, the enzyme F(420)-γ-glutamyl ligase (FbiB) catalyzes the addition of γ-linked L-glutamate residues to form polyglutamylated F(420) derivatives. In Mycobacterium tuberculosis, Rv3262 (FbiB) consists of two domains: an N-terminal domain from the F(420) ligase superfamily and a C-terminal domain with sequence similarity to nitro-FMN reductase superfamily proteins. To characterize the role of the C-terminal domain of FbiB in polyglutamyl ligation, it has been purified and crystallized in an apo form. The crystals diffracted to 2.0 Å resolution using a synchrotron source and belonged to the tetragonal space group P4(1)2(1)2 (or P4(3)2(1)2), with unit-cell parameters a = b = 136.6, c = 101.7 Å, α = β = γ = 90°.
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Affiliation(s)
- Aisyah M Rehan
- Structural Biology Laboratory, School of Biological Sciences, The University of Auckland, Auckland, New Zealand.
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28
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Bashiri G, Rehan AM, Greenwood DR, Dickson JMJ, Baker EN. Metabolic engineering of cofactor F420 production in Mycobacterium smegmatis. PLoS One 2010; 5:e15803. [PMID: 21209917 PMCID: PMC3012119 DOI: 10.1371/journal.pone.0015803] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 11/24/2010] [Indexed: 01/16/2023] Open
Abstract
Cofactor F420 is a unique electron carrier in a number of microorganisms including Archaea and Mycobacteria. It has been shown that F420 has a direct and important role in archaeal energy metabolism whereas the role of F420 in mycobacterial metabolism has only begun to be uncovered in the last few years. It has been suggested that cofactor F420 has a role in the pathogenesis of M. tuberculosis, the causative agent of tuberculosis. In the absence of a commercial source for F420, M. smegmatis has previously been used to provide this cofactor for studies of the F420-dependent proteins from mycobacterial species. Three proteins have been shown to be involved in the F420 biosynthesis in Mycobacteria and three other proteins have been demonstrated to be involved in F420 metabolism. Here we report the over-expression of all of these proteins in M. smegmatis and testing of their importance for F420 production. The results indicate that co–expression of the F420 biosynthetic proteins can give rise to a much higher F420 production level. This was achieved by designing and preparing a new T7 promoter–based co-expression shuttle vector. A combination of co–expression of the F420 biosynthetic proteins and fine-tuning of the culture media has enabled us to achieve F420 production levels of up to 10 times higher compared with the wild type M. smegmatis strain. The high levels of the F420 produced in this study provide a suitable source of this cofactor for studies of F420-dependent proteins from other microorganisms and for possible biotechnological applications.
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Affiliation(s)
- Ghader Bashiri
- Structural Biology Laboratory, School of Biological Sciences, The University of Auckland, Auckland, New Zealand.
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29
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Unexpected abundance of coenzyme F(420)-dependent enzymes in Mycobacterium tuberculosis and other actinobacteria. J Bacteriol 2010; 192:5788-98. [PMID: 20675471 DOI: 10.1128/jb.00425-10] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regimens targeting Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), require long courses of treatment and a combination of three or more drugs. An increase in drug-resistant strains of M. tuberculosis demonstrates the need for additional TB-specific drugs. A notable feature of M. tuberculosis is coenzyme F(420), which is distributed sporadically and sparsely among prokaryotes. This distribution allows for comparative genomics-based investigations. Phylogenetic profiling (comparison of differential gene content) based on F(420) biosynthesis nominated many actinobacterial proteins as candidate F(420)-dependent enzymes. Three such families dominated the results: the luciferase-like monooxygenase (LLM), pyridoxamine 5'-phosphate oxidase (PPOX), and deazaflavin-dependent nitroreductase (DDN) families. The DDN family was determined to be limited to F(420)-producing species. The LLM and PPOX families were observed in F(420)-producing species as well as species lacking F(420) but were particularly numerous in many actinobacterial species, including M. tuberculosis. Partitioning the LLM and PPOX families based on an organism's ability to make F(420) allowed the application of the SIMBAL (sites inferred by metabolic background assertion labeling) profiling method to identify F(420)-correlated subsequences. These regions were found to correspond to flavonoid cofactor binding sites. Significantly, these results showed that M. tuberculosis carries at least 28 separate F(420)-dependent enzymes, most of unknown function, and a paucity of flavin mononucleotide (FMN)-dependent proteins in these families. While prevalent in mycobacteria, markers of F(420) biosynthesis appeared to be absent from the normal human gut flora. These findings suggest that M. tuberculosis relies heavily on coenzyme F(420) for its redox reactions. This dependence and the cofactor's rarity may make F(420)-related proteins promising drug targets.
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Autofluorescence of mycobacteria as a tool for detection of Mycobacterium tuberculosis. J Clin Microbiol 2008; 46:3296-302. [PMID: 18836064 DOI: 10.1128/jcm.02183-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diagnosis of tuberculosis in developing countries still relies on direct sputum examination by light microscopy, a method that is easy to perform and that is widely applied. However, because of its poor sensitivity and requirement for significant labor and training, light microscopy examination detects the bacilli in only 45 to 60% of all people whose specimens are culture positive for Mycobacterium tuberculosis. Therefore, new diagnostic methods that would enable the detection of the undiagnosed infected population and allow the early commencement of antituberculosis treatment are needed. In this work, the potential use of mycobacterial cyan autofluorescence for the detection of Mycobacterium tuberculosis was explored. The tubercle bacilli were easily visualized as brilliant fluorescent bacilli by microscopy and were easily tracked ex vivo during macrophage infection. Assays with seeded sputum and a 96-well microplate reader fluorimeter indicated that <10(6) bacilli ml(-1) of sputum could be detected. Moreover, the use of microplates allowed the examination of only 200 microl of sputum per sample without a loss of sensitivity. Treatment with heat or decontaminating chemical agents did not interfere with the autofluorescence assay; on the contrary, they improved the level of bacterial detection. Autofluorescence for the detection of bacilli is rapid and easy to perform compared to other methodologies and can be performed with minimal training, making this method suitable for implementation in developing countries.
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Bashiri G, Squire CJ, Moreland NJ, Baker EN. Crystal Structures of F420-dependent Glucose-6-phosphate Dehydrogenase FGD1 Involved in the Activation of the Anti-tuberculosis Drug Candidate PA-824 Reveal the Basis of Coenzyme and Substrate Binding. J Biol Chem 2008; 283:17531-41. [DOI: 10.1074/jbc.m801854200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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32
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Forouhar F, Abashidze M, Xu H, Grochowski LL, Seetharaman J, Hussain M, Kuzin A, Chen Y, Zhou W, Xiao R, Acton TB, Montelione GT, Galinier A, White RH, Tong L. Molecular insights into the biosynthesis of the F420 coenzyme. J Biol Chem 2008; 283:11832-40. [PMID: 18252724 PMCID: PMC2431047 DOI: 10.1074/jbc.m710352200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 01/28/2008] [Indexed: 11/06/2022] Open
Abstract
Coenzyme F(420), a hydride carrier, is found in Archaea and some bacteria and has crucial roles in methanogenesis, antibiotic biosynthesis, DNA repair, and activation of antitubercular compounds. CofD, 2-phospho-l-lactate transferase, catalyzes the last step in the biosynthesis of F(420)-0 (F(420) without polyglutamate), by transferring the lactyl phosphate moiety of lactyl(2)diphospho-(5')guanosine to 7,8-didemethyl-8-hydroxy-5-deazariboflavin ribitol (Fo). CofD is highly conserved among F(420)-producing organisms, and weak sequence homologs are also found in non-F(420)-producing organisms. This superfamily does not share any recognizable sequence conservation with other proteins. Here we report the first crystal structures of CofD, the free enzyme and two ternary complexes, with Fo and P(i) or with Fo and GDP, from Methanosarcina mazei. The active site is located at the C-terminal end of a Rossmann fold core, and three large insertions make significant contributions to the active site and dimer formation. The observed binding modes of Fo and GDP can explain known biochemical properties of CofD and are also supported by our binding assays. The structures provide significant molecular insights into the biosynthesis of the F(420) coenzyme. Large structural differences in the active site region of the non-F(420)-producing CofD homologs suggest that they catalyze a different biochemical reaction.
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Affiliation(s)
- Farhad Forouhar
- Department of Biological Sciences, Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, USA
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33
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Guerra-Lopez D, Daniels L, Rawat M. Mycobacterium smegmatis mc2 155 fbiC and MSMEG_2392 are involved in triphenylmethane dye decolorization and coenzyme F420 biosynthesis. Microbiology (Reading) 2007; 153:2724-2732. [PMID: 17660436 DOI: 10.1099/mic.0.2006/009241-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mycobacteria can tolerate relatively high concentrations of triphenylmethane dyes such as malachite green and methyl violet. To identify mycobacterial genes involved in the decolorization of malachite green, a transposon mutant library of Mycobacterium smegmatis mc2 155 was screened for mutants unable to decolorize this dye. One of the genes identified was MSMEG_5126, an orthologue of Mycobacterium bovis fbiC encoding a 7,8-didemethyl-8-hydroxy-5-deazariboflavin (FO) synthase, which is essential for the biosynthesis of the electron carrier coenzyme F420. The other gene identified was MSMEG_2392, encoding an alanine-rich protein with a DUF121 domain. The minimum inhibitory concentrations (MICs) for malachite green and methyl violet of the six fbiC mutants and two MSMEG_2392 mutants were one-third and one-fifth, respectively, of the MIC of the parent strain M. smegmatis mc2 155. Representative fbiC and MSMEG_2392 mutant strains were also sensitive to oxidative stress caused by the redox-cycling agents plumbagin and menadione, and the sensitivity was reversed in the complemented strains. HPLC analysis of representative fbiC and MSMEG_2392 strains revealed that, while the fbiC mutant lacked both coenzyme F420 and FO, the MSMEG_2392 mutant contained FO but not coenzyme F420. These results indicate that MSMEG_2392 is involved in the biosynthesis of coenzyme F420.
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Affiliation(s)
- Denise Guerra-Lopez
- Department of Biology, California State University-Fresno, Fresno, CA 937401, USA
| | - Lacy Daniels
- Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, TX 78363, USA
| | - Mamta Rawat
- Department of Biology, California State University-Fresno, Fresno, CA 937401, USA
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34
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Bashiri G, Squire CJ, Baker EN, Moreland NJ. Expression, purification and crystallization of native and selenomethionine labeled Mycobacterium tuberculosis FGD1 (Rv0407) using a Mycobacterium smegmatis expression system. Protein Expr Purif 2007; 54:38-44. [PMID: 17376702 DOI: 10.1016/j.pep.2007.01.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 01/22/2007] [Accepted: 01/24/2007] [Indexed: 10/23/2022]
Abstract
FGD1 is an F(420)-dependent glucose-6-phosphate dehydrogenase from Mycobacterium tuberculosis that has been shown to be essential for activation of the anti-TB compound PA-824. Initial attempts to produce recombinant FGD1 using Escherichia coli as a host was unsuccessful, but when the alternative host Mycobacterium smegmatis was used, soluble protein yields of 7 mg/L of culture were achieved. Both native and selenomethionine-substituted FGD1 were obtained by culturing M. smegmatis in autoinduction media protocols originally developed for E. coli. Using these media afforded the advantages of decreased handling, as cultures did not require monitoring of optical density and induction, and reduced cost by removing the need for expensive ADC enrichment normally used in mycobacterial cultures. Selenomethionine was efficiently incorporated at levels required for multiwavelength anomalous diffraction experiments used in crystal structure determination. As far as we are aware this is the first protocol for preparation of selenomethionine-substituted protein in mycobacteria. Native and selenomethionine-labeled FGD1 were successfully crystallized by vapor diffusion, with the crystals diffracting to 2.1 Angstrom resolution.
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Affiliation(s)
- Ghader Bashiri
- Maurice Wilkins Center for Molecular Biodiscovery, Laboratory of Structural Biology, School of Biological Sciences, University of Auckland, Private Bag 92019, New Zealand
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35
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Manjunatha UH, Boshoff H, Dowd CS, Zhang L, Albert TJ, Norton JE, Daniels L, Dick T, Pang SS, Barry CE. Identification of a nitroimidazo-oxazine-specific protein involved in PA-824 resistance in Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2006; 103:431-6. [PMID: 16387854 PMCID: PMC1326169 DOI: 10.1073/pnas.0508392103] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Accepted: 11/21/2005] [Indexed: 11/18/2022] Open
Abstract
PA-824 is a promising new compound for the treatment of tuberculosis that is currently undergoing human trials. Like its progenitors metronidazole and CGI-17341, PA-824 is a prodrug of the nitroimidazole class, requiring bioreductive activation of an aromatic nitro group to exert an antitubercular effect. We have confirmed that resistance to PA-824 (a nitroimidazo-oxazine) and CGI-17341 (a nitroimidazo-oxazole) is most commonly mediated by loss of a specific glucose-6-phosphate dehydrogenase (FGD1) or its deazaflavin cofactor F420, which together provide electrons for the reductive activation of this class of molecules. Although FGD1 and F420 are necessary for sensitivity to these compounds, they are not sufficient and require additional accessory proteins that directly interact with the nitroimidazole. To understand more proximal events in the reductive activation of PA-824, we examined mutants that were wild-type for both FGD1 and F420 and found that, although these mutants had acquired high-level resistance to PA-824 (and another nitroimidazo-oxazine), they retained sensitivity to CGI-17341 (and a related nitroimidazo-oxazole). Microarray-based comparative genome sequencing of these mutants identified lesions in Rv3547, a conserved hypothetical protein with no known function. Complementation with intact Rv3547 fully restored sensitivity to nitroimidazo-oxazines and restored the ability of Mtb to metabolize PA-824. These results suggest that the sensitivity of Mtb to PA-824 and related compounds is mediated by a protein that is highly specific for subtle structural variations in these bicyclic nitroimidazoles.
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Affiliation(s)
- Ujjini H Manjunatha
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, 12441 Parklawn Drive, Twinbrook II, Rockville, MD 20852, USA
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36
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Abstract
The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate. The imidazole ring of GTP is hydrolytically opened, yielding a 2,5-diaminopyrimidine that is converted to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction, and dephosphorylation. Condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate affords 6,7-dimethyl-8-ribityllumazine. Dismutation of the lumazine derivative yields riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is recycled in the biosynthetic pathway. The enzymes of the riboflavin pathway are potential targets for antibacterial agents.
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Affiliation(s)
- Markus Fischer
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747, Garching, Germany.
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37
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Graupner M, White RH. Methanococcus jannaschii coenzyme F420 analogs contain a terminal alpha-linked glutamate. J Bacteriol 2003; 185:4662-5. [PMID: 12867481 PMCID: PMC165758 DOI: 10.1128/jb.185.15.4662-4665.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Accepted: 05/12/2003] [Indexed: 11/20/2022] Open
Abstract
Analyses of the F(420)s present in Methanococcus jannaschii have shown that these cells contain a series of gamma-glutamyl-linked F(420)s capped with a single, terminal alpha-linked L-glutamate. The predominant form of F(420) was designated as alpha-F(420)-3 and represented 86% of the F(420)s in these cells. Analyses of Methanosarcina thermophila, Methanosarcina barkeri, Methanobacterium thermoautotrophicum, Archaeoglobus fulgidus, and Mycobacterium smegmatis showed that they contained only gamma-glutamyl-linked F(420)s.
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Affiliation(s)
- Marion Graupner
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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38
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Isabelle D, Simpson DR, Daniels L. Large-scale production of coenzyme F420-5,6 by using Mycobacterium smegmatis. Appl Environ Microbiol 2002; 68:5750-5. [PMID: 12406775 PMCID: PMC129890 DOI: 10.1128/aem.68.11.5750-5755.2002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Production of coenzyme F420 and its biosynthetic precursor FO was examined with a variety of aerobic actinomycetes to identify an improved source for these materials. Based on fermentation costs, safety, and ease of growth, Mycobacterium smegmatis was the best source for F420-5,6. M. smegmatis produced 1 to 3 micromol of intracellular F420 per liter of culture, which was more than the 0.85 to 1.0 micromol of F420-2 per liter usually obtained with Methanobacterium thermoautotrophicum and approximately 10-fold higher than what was previously reported for the best aerobic actinomycetes. An improved chromatography system using rapidly flowing quaternary aminoethyl ion-exchange material and Florisil was used to more quickly and easily purify F420 than with previous methods.
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Affiliation(s)
- Dale Isabelle
- Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, USA
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39
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Choi KP, Kendrick N, Daniels L. Demonstration that fbiC is required by Mycobacterium bovis BCG for coenzyme F(420) and FO biosynthesis. J Bacteriol 2002; 184:2420-8. [PMID: 11948155 PMCID: PMC134996 DOI: 10.1128/jb.184.9.2420-2428.2002] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using the nitroimidazopyran-based antituberculosis drug PA-824 as a selective agent, transposon-generated Mycobacterium bovis strain BCG (M. bovis) mutants that could not make coenzyme F(420) were identified. Four independent mutants that could not make F(420) or the biosynthesis intermediate FO were examined more closely. These mutants contained transposons inserted in the M. bovis homologue of the Mycobacterium tuberculosis gene Rv1173, which we have named fbiC. Complementation of an M. bovis FbiC(-) mutant with fbiC restored the F(420) phenotype. These data demonstrate that fbiC is essential for F(420) production and that FbiC participates in a portion of the F(420) biosynthetic pathway between pyrimidinedione and FO. Homologues of fbiC were found in all 11 microorganisms that have been fully sequenced and that are known to make F(420). Four of these homologues (all from members of the aerobic actinomycetes) coded for proteins homologous over the entire length of the M. bovis FbiC, but in seven microorganisms two separate genes were found to code for proteins homologous with either the N-terminal or C-terminal portions of the M. bovis FbiC. Histidine-tagged FbiC overexpressed in Escherichia coli produced a fusion protein of the molecular mass predicted from the M. bovis BCG sequence (approximately 95,000 Da), as well as three other histidine-tagged proteins of significantly smaller size, which are thought to be proteolysis products of the FbiC fusion protein.
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Affiliation(s)
- Kwang-Pil Choi
- Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, USA
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40
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Choi KP, Bair TB, Bae YM, Daniels L. Use of transposon Tn5367 mutagenesis and a nitroimidazopyran-based selection system to demonstrate a requirement for fbiA and fbiB in coenzyme F(420) biosynthesis by Mycobacterium bovis BCG. J Bacteriol 2001; 183:7058-66. [PMID: 11717263 PMCID: PMC95553 DOI: 10.1128/jb.183.24.7058-7066.2001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three transposon Tn5367 mutagenesis vectors (phAE94, pPR28, and pPR29) were used to create a collection of insertion mutants of Mycobacterium bovis strain BCG. A strategy to select for transposon-generated mutants that cannot make coenzyme F(420) was developed using the nitroimidazopyran-based antituberculosis drug PA-824. One-third of 134 PA-824-resistant mutants were defective in F(420) accumulation. Two mutants that could not make F(420)-5,6 but which made the biosynthesis intermediate FO were examined more closely. These mutants contained transposons inserted in two adjacent homologues of Mycobacterium tuberculosis genes, which we have named fbiA and fbiB for F(420) biosynthesis. Homologues of fbiA were found in all seven microorganisms that have been fully sequenced and annotated and that are known to make F(420). fbiB homologues were found in all but one such organism. Complementation of the fbiA mutant with fbiAB and complementation of the fbiB mutant with fbiB both restored the F(420)-5,6 phenotype. Complementation of the fbiA mutant with fbiA or fbiB alone did not restore the F(420)-5,6 phenotype, but the fbiA mutant complemented with fbiA produced F(420)-2,3,4 at levels similar to F(420)-5,6 made by the wild-type strain, but produced much less F(420)-5. These data demonstrate that both genes are essential for normal F(420)-5,6 production and suggest that the fbiA mutation has a partial polar effect on fbiB. Reverse transcription-PCR data demonstrated that fbiA and fbiB constitute an operon. However, very low levels of fbiB mRNA are produced by the fbiA mutant, suggesting that a low-level alternative start site is located upstream of fbiB. The specific reactions catalyzed by FbiA and FbiB are unknown, but both function between FO and F(420)-5,6, since FO is made by both mutants.
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Affiliation(s)
- K P Choi
- Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, USA
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