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Luo Z, Li Z, Sun J, Shi K, Lei M, Tie B, Du H. Multiple mechanisms collectively mediate tungsten homeostasis and resistance in Citrobacter sp. Lzp2. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130877. [PMID: 36731318 DOI: 10.1016/j.jhazmat.2023.130877] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/19/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Tungsten (W) is an emerging contaminant, and current knowledge on W resistance profiles of microorganisms remains scarce and fragmentary. This study aimed to explore the physiological responses of bacteria under W stress and to resolve genes and metabolic pathways involved in W resistance using a transcriptome expression profiling assay. The results showed that the bacterium Citrobacter sp. Lzp2, screened from W-contaminated soil, could tolerate hundreds of mM W(VI) with a 50% inhibiting concentration of ∼110 mM. To cope with W stress, Citrobacter sp. Lzp2 secreted large amounts of proteins through the type VI secretory system (T6SS) to chelate W oxoanions via carboxylic groups in extracellular polymeric substances (EPS), and could transport cytosolic W outside via the multidrug efflux pumps (mdtABC and acrD). Intracellular W is probably bound by chaperone proteins and metal-binding pterin (tungstopterin) through the sulfur relay system. We propose that tetrathionate respiration is a new metabolic pathway for cellular W detoxification likely producing thio-tungstate. We conclude that multiple mechanisms collectively mediate W homeostasis and resistance in Citrobacter sp. Lzp2. Our results have important implications not only for understanding the intricate regulatory network of W homeostasis in microbes but also for bio-recovery and bioremediation of W in contaminated environments.
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Affiliation(s)
- Zipei Luo
- College of Resources and Environment, Hunan Agricultural University, 410127 Changsha, China
| | - Zhen Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, 210095 Nanjing, China
| | - Jing Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081 Guiyang, China
| | - Kaixiang Shi
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ming Lei
- College of Resources and Environment, Hunan Agricultural University, 410127 Changsha, China
| | - Boqing Tie
- College of Resources and Environment, Hunan Agricultural University, 410127 Changsha, China
| | - Huihui Du
- College of Resources and Environment, Hunan Agricultural University, 410127 Changsha, China.
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Beliaeva M, Seebeck FP. Discovery and Characterization of the Metallopterin-Dependent Ergothioneine Synthase from Caldithrix abyssi. JACS AU 2022; 2:2098-2107. [PMID: 36186560 PMCID: PMC9516567 DOI: 10.1021/jacsau.2c00365] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 05/29/2023]
Abstract
Ergothioneine is a histidine derivative with a 2-mercaptoimidazole side chain and a trimethylated α-amino group. Although the physiological function of this natural product is not yet understood, the facts that many bacteria, some archaea, and most fungi produce ergothioneine and that plants and animals have specific mechanisms to absorb and distribute ergothioneine in specific tissues suggest a fundamental role in cellular life. The observation that ergothioneine biosynthesis has emerged multiple times in molecular evolution points to the same conclusion. Aerobic bacteria and fungi attach sulfur to the imidazole ring of trimethylhistidine via an O2-dependent reaction that is catalyzed by a mononuclear non-heme iron enzyme. Green sulfur bacteria and archaea use a rhodanese-like sulfur transferase to attach sulfur via oxidative polar substitution. In this report, we describe a third unrelated class of enzymes that catalyze sulfur transfer in ergothioneine production. The metallopterin-dependent ergothioneine synthase from Caldithrix abyssi contains an N-terminal module that is related to the tungsten-dependent acetylene hydratase and a C-terminal domain that is a functional cysteine desulfurase. The two modules cooperate to transfer sulfur from cysteine onto trimethylhistidine. Inactivation of the C-terminal desulfurase blocks ergothioneine production but maintains the ability of the metallopterin to exchange sulfur between ergothioneine and trimethylhistidine. Homologous bifunctional enzymes are encoded exclusively in anaerobic bacterial and archaeal species.
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Affiliation(s)
- Mariia
A. Beliaeva
- Department
of Chemistry, University of Basel, Mattenstrasse 24a, 4002 Basel, Switzerland
- Molecular
Systems Engineering, National Competence
Center in Research (NCCR), 4058 Basel, Switzerland
| | - Florian P. Seebeck
- Department
of Chemistry, University of Basel, Mattenstrasse 24a, 4002 Basel, Switzerland
- Molecular
Systems Engineering, National Competence
Center in Research (NCCR), 4058 Basel, Switzerland
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3
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Ćorović MZ, Wiedemaier F, Belaj F, Mösch-Zanetti NC. Replacement of Molybdenum by Tungsten in a Biomimetic Complex Leads to an Increase in Oxygen Atom Transfer Catalytic Activity. Inorg Chem 2022; 61:12415-12424. [PMID: 35894844 PMCID: PMC9367641 DOI: 10.1021/acs.inorgchem.2c01868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Upon replacement of molybdenum by tungsten in DMSO reductase isolated from the Rhodobacteraceae family, the derived enzyme catalyzes DMSO reduction faster. To better understand this behavior, we synthesized two tungsten(VI) dioxido complexes [WVIO2L2] with pyridine- (PyS) and pyrimidine-2-thiolate (PymS) ligands, isostructural to analogous molybdenum complexes we reported recently. Higher oxygen atom transfer (OAT) catalytic activity was observed with [WO2(PyS)2] compared to the Mo species, independent of whether PMe3 or PPh3 was used as the oxygen acceptor. [WVIO2L2] complexes undergo reduction with an excess of PMe3, yielding the tungsten(IV) oxido species [WOL2(PMe3)2], while with PPh3, no reactions are observed. Although OAT reactions from DMSO to phosphines are known for tungsten complexes, [WOL2(PMe3)2] are the first fully characterized phosphine-stabilized intermediates. By following the reaction of these reduced species with excess DMSO via UV-vis spectroscopy, we observed that tungsten compounds directly react to WVIO2 complexes while the Mo analogues first form μ-oxo Mo(V) dimers [Mo2O3L4]. Density functional theory calculations confirm that the oxygen atom abstraction from WVIO2 is an endergonic process contrasting the respective reaction with molybdenum. Here, we suggest that depending on the sacrificial oxygen acceptor, the tungsten complex may participate in catalysis either via a redox reaction or as an electrophile.
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Affiliation(s)
- Miljan Z Ćorović
- Institute of Chemistry, Inorganic Chemistry, University of Graz, 8010 Graz, Austria
| | - Fabian Wiedemaier
- Institute of Chemistry, Inorganic Chemistry, University of Graz, 8010 Graz, Austria
| | - Ferdinand Belaj
- Institute of Chemistry, Inorganic Chemistry, University of Graz, 8010 Graz, Austria
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4
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Harnessing Escherichia coli for Bio-Based Production of Formate under Pressurized H 2 and CO 2 Gases. Appl Environ Microbiol 2021; 87:e0029921. [PMID: 34647819 DOI: 10.1128/aem.00299-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Escherichia coli is a Gram-negative bacterium that is a workhorse for biotechnology. The organism naturally performs a mixed-acid fermentation under anaerobic conditions where it synthesizes formate hydrogenlyase (FHL-1). The physiological role of the enzyme is the disproportionation of formate into H2 and CO2. However, the enzyme has been observed to catalyze hydrogenation of CO2 given the correct conditions, and so it has possibilities in bio-based carbon capture and storage if it can be harnessed as a hydrogen-dependent CO2 reductase (HDCR). In this study, an E. coli host strain was engineered for the continuous production of formic acid from H2 and CO2 during bacterial growth in a pressurized batch bioreactor. Incorporation of tungsten, in place of molybdenum, in FHL-1 helped to impose a degree of catalytic bias on the enzyme. This work demonstrates that it is possible to couple cell growth to simultaneous, unidirectional formate production from carbon dioxide and develops a process for growth under pressurized gases. IMPORTANCE Greenhouse gas emissions, including waste carbon dioxide, are contributing to global climate change. A basket of solutions is needed to steadily reduce emissions, and one approach is bio-based carbon capture and storage. Here, we present our latest work on harnessing a novel biological solution for carbon capture. The Escherichia coli formate hydrogenlyase (FHL-1) was engineered to be constitutively expressed. Anaerobic growth under pressurized H2 and CO2 gases was established, and aqueous formic acid was produced as a result. Incorporation of tungsten into the enzyme in place of molybdenum proved useful in poising FHL-1 as a hydrogen-dependent CO2 reductase (HDCR).
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Rapid Detection of Gut Microbial Metabolite Trimethylamine N-Oxide for Chronic Kidney Disease Prevention. BIOSENSORS-BASEL 2021; 11:bios11090339. [PMID: 34562929 PMCID: PMC8469701 DOI: 10.3390/bios11090339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/07/2021] [Accepted: 09/10/2021] [Indexed: 01/21/2023]
Abstract
The gut microbiota plays a critical role in chronic kidney disease (CKD) and hypertension. Trimethylamine-N-oxide (TMAO) and trimethylamine (TMA) are gut microbiota-derived metabolites, and both are known uraemic toxins that are implicated in CKD, atherosclerosis, colorectal cancer and cardiovascular risk. Therefore, the detection and quantification of TMAO, which is a metabolite from gut microbes, are important for the diagnosis of diseases such as atherosclerosis, thrombosis and colorectal cancer. In this study, a new “colour-switch” method that is based on the combination of a plasma separation pad/absorption pad and polyallylamine hydrochloride-capped manganese dioxide (PAH@MnO2) nanozyme was developed for the direct quantitative detection of TMAO in whole blood without blood sample pretreatment. As a proof of concept, a limit of quantitation (LOQ) of less than 6.7 μM for TMAO was obtained with a wide linear quantification range from 15.6 to 500 μM through quantitative analysis, thereby suggesting potential clinical applications in blood TMAO monitoring for CKD patients.
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Waffo AFT, Mitrova B, Tiedemann K, Iobbi-Nivol C, Leimkühler S, Wollenberger U. Electrochemical Trimethylamine N-Oxide Biosensor with Enzyme-Based Oxygen-Scavenging Membrane for Long-Term Operation under Ambient Air. BIOSENSORS 2021; 11:bios11040098. [PMID: 33801724 PMCID: PMC8066520 DOI: 10.3390/bios11040098] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 05/28/2023]
Abstract
An amperometric trimethylamine N-oxide (TMAO) biosensor is reported, where TMAO reductase (TorA) and glucose oxidase (GOD) and catalase (Cat) were immobilized on the electrode surface, enabling measurements of mediated enzymatic TMAO reduction at low potential under ambient air conditions. The oxygen anti-interference membrane composed of GOD, Cat and polyvinyl alcohol (PVA) hydrogel, together with glucose concentration, was optimized until the O2 reduction current of a Clark-type electrode was completely suppressed for at least 3 h. For the preparation of the TMAO biosensor, Escherichia coli TorA was purified under anaerobic conditions and immobilized on the surface of a carbon electrode and covered by the optimized O2 scavenging membrane. The TMAO sensor operates at a potential of -0.8 V vs. Ag/AgCl (1 M KCl), where the reduction of methylviologen (MV) is recorded. The sensor signal depends linearly on TMAO concentrations between 2 µM and 15 mM, with a sensitivity of 2.75 ± 1.7 µA/mM. The developed biosensor is characterized by a response time of about 33 s and an operational stability over 3 weeks. Furthermore, measurements of TMAO concentration were performed in 10% human serum, where the lowest detectable concentration is of 10 µM TMAO.
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Affiliation(s)
- Armel F. T. Waffo
- Institute for Biochemistry and Biology, University Potsdam, 14476 Potsdam, Germany; (A.F.T.W.); (B.M.); (K.T.); (S.L.)
| | - Biljana Mitrova
- Institute for Biochemistry and Biology, University Potsdam, 14476 Potsdam, Germany; (A.F.T.W.); (B.M.); (K.T.); (S.L.)
| | - Kim Tiedemann
- Institute for Biochemistry and Biology, University Potsdam, 14476 Potsdam, Germany; (A.F.T.W.); (B.M.); (K.T.); (S.L.)
| | - Chantal Iobbi-Nivol
- CNRS, Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Laboratoire de Bioénergétique et Ingénierie des Protéines, 13402 Marseille, France;
| | - Silke Leimkühler
- Institute for Biochemistry and Biology, University Potsdam, 14476 Potsdam, Germany; (A.F.T.W.); (B.M.); (K.T.); (S.L.)
| | - Ulla Wollenberger
- Institute for Biochemistry and Biology, University Potsdam, 14476 Potsdam, Germany; (A.F.T.W.); (B.M.); (K.T.); (S.L.)
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7
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Bioinformatics analysis and biochemical characterisation of ABC transporter-associated periplasmic substrate-binding proteins ModA and MetQ from Helicobacter pylori strain SS1. Biophys Chem 2021; 272:106577. [PMID: 33756269 DOI: 10.1016/j.bpc.2021.106577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/23/2021] [Accepted: 03/06/2021] [Indexed: 12/29/2022]
Abstract
The human gastric pathogen Helicobacter pylori relies on the uptake of host-provided nutrients for its proliferation and pathogenicity. ABC transporters that mediate import of small molecules into the cytoplasm of H. pylori employ their cognate periplasmic substrate-binding proteins (SBPs) for ligand capture in the periplasm. The genome of the mouse-adapted strain SS1 of H. pylori encodes eight ABC transporter-associated SBPs, but little is known about their specificity or structure. In this study, we demonstrated that the SBP annotated as ModA binds molybdate (MoO42-, KD = 3.8 nM) and tungstate (WO42-, KD = 7.8 nM). In addition, we showed that MetQ binds D-methionine (KD = 9.5 μM), but not L-methionine, which suggests the existence of as yet unknown pathway for L-methionine uptake. Homology modelling has led to identification of the ligand-binding residues.
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8
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Abstract
Tungsten is the heaviest element used in biological systems. It occurs in the active sites of several bacterial or archaeal enzymes and is ligated to an organic cofactor (metallopterin or metal binding pterin; MPT) which is referred to as tungsten cofactor (Wco). Wco-containing enzymes are found in the dimethyl sulfoxide reductase (DMSOR) and the aldehyde:ferredoxin oxidoreductase (AOR) families of MPT-containing enzymes. Some depend on Wco, such as aldehyde oxidoreductases (AORs), class II benzoyl-CoA reductases (BCRs) and acetylene hydratases (AHs), whereas others may incorporate either Wco or molybdenum cofactor (Moco), such as formate dehydrogenases, formylmethanofuran dehydrogenases or nitrate reductases. The obligately tungsten-dependent enzymes catalyze rather unusual reactions such as ones with extremely low-potential electron transfers (AOR, BCR) or an unusual hydration reaction (AH). In recent years, insights into the structure and function of many tungstoenzymes have been obtained. Though specific and unspecific ABC transporter uptake systems have been described for tungstate and molybdate, only little is known about further discriminative steps in Moco and Wco biosynthesis. In bacteria producing Moco- and Wco-containing enzymes simultaneously, paralogous isoforms of the metal insertase MoeA may be specifically involved in the molybdenum- and tungsten-insertion into MPT, and in targeting Moco or Wco to their respective apo-enzymes. Wco-containing enzymes are of emerging biotechnological interest for a number of applications such as the biocatalytic reduction of CO2, carboxylic acids and aromatic compounds, or the conversion of acetylene to acetaldehyde.
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Characterization of thiosulfate reductase from Pyrobaculum aerophilum heterologously produced in Pyrococcus furiosus. Extremophiles 2019; 24:53-62. [PMID: 31278423 DOI: 10.1007/s00792-019-01112-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/26/2019] [Indexed: 10/26/2022]
Abstract
The genome of the archaeon Pyrobaculum aerophilum (Topt ~ 100 °C) contains an operon (PAE2859-2861) encoding a putative pyranopterin-containing oxidoreductase of unknown function and metal content. These genes (with one gene modified to encode a His-affinity tag) were inserted into the fermentative anaerobic archaeon, Pyrococcus furiosus (Topt ~ 100 °C). Dye-linked assays of cytoplasmic extracts from recombinant P. furiosus show that the P. aerophilum enzyme is a thiosulfate reductase (Tsr) and reduces thiosulfate but not polysulfide. The enzyme (Tsr-Mo) from molybdenum-grown cells contains Mo (Mo:W = 9:1) while the enzyme (Tsr-W) from tungsten-grown cells contains mainly W (Mo:W = 1:6). Purified Tsr-Mo has over ten times the activity (Vmax = 1580 vs. 141 µmol min-1 mg-1) and twice the affinity for thiosulfate (Km = ~ 100 vs. ~ 200 μM) than Tsr-W and is reduced at a lower potential (Epeak = - 255 vs - 402 mV). Tsr-Mo and Tsr-W proteins are heterodimers lacking the membrane anchor subunit (PAE2861). Recombinant P. furiosus expressing P. aerophilum Tsr could not use thiosulfate as a terminal electron acceptor. P. furiosus contains five pyranopterin-containing enzymes, all of which utilize W. P. aerophilum Tsr-Mo is the first example of an active Mo-containing enzyme produced in P. furiosus.
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Mitrova B, Waffo AFT, Kaufmann P, Iobbi‐Nivol C, Leimkühler S, Wollenberger U. Trimethylamine
N
‐Oxide Electrochemical Biosensor with a Chimeric Enzyme. ChemElectroChem 2018. [DOI: 10.1002/celc.201801422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Biljana Mitrova
- Institute for Biochemistry and BiologyUniversity Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
| | - Armel F. T. Waffo
- Institute for Biochemistry and BiologyUniversity Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
| | - Paul Kaufmann
- Institute for Biochemistry and BiologyUniversity Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
| | | | - Silke Leimkühler
- Institute for Biochemistry and BiologyUniversity Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
| | - Ulla Wollenberger
- Institute for Biochemistry and BiologyUniversity Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
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12
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Qian HX, Liao RZ. QM/MM Study of Tungsten-Dependent Benzoyl-Coenzyme A Reductase: Rationalization of Regioselectivity and Predication of W vs Mo Selectivity. Inorg Chem 2018; 57:10667-10678. [DOI: 10.1021/acs.inorgchem.8b01328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hui-Xia Qian
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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13
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Okamura TA, Omi Y, Hirano Y, Onitsuka K. Comparative studies on the contribution of NHS hydrogen bonds in tungsten and molybdenum benzenedithiolate complexes. Dalton Trans 2018; 45:15651-15659. [PMID: 27722343 DOI: 10.1039/c6dt02250b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of monooxotungsten(iv) and dioxotungsten(vi) benzenedithiolates, (NEt4)2[WIVO(1,2-S2-3-RCONHC6H3)2] (1-W; R = CH3 (a), t-Bu (b), or CF3 (c)) and (NEt4)2[WVIO2(1,2-S2-3-RCONHC6H3)2] (2-W), were synthesized and compared with the corresponding molybdenum analogues. Single crystals of trans-1b-W were successfully obtained, and the crystal structure was determined by X-ray analysis although 1b-Mo could not be crystallized. The NHS hydrogen bonds shifted the potential of the W(iv/v) redox couple to more positive values, and the strength of the hydrogen bond and the positive shift value were strongly correlated. The hydrogen bonds in both 1-W and 2-W were weaker than those in the corresponding molybdenum analogues; however, the effect of the hydrogen bonds on the redox potential was greater in 1-W.
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Affiliation(s)
- Taka-Aki Okamura
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - Yui Omi
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - Yasunori Hirano
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - Kiyotaka Onitsuka
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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Synthesis and solution structure of desoxotungsten(IV) and monooxotungsten(VI) benzenedithiolate complexes containing two intramolecular NH⋯S hydrogen bonds. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.08.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Habib U, Hoffman M. Effect of molybdenum and tungsten on the reduction of nitrate in nitrate reductase, a DFT study. Chem Cent J 2017; 11:35. [PMID: 29086812 PMCID: PMC5405038 DOI: 10.1186/s13065-017-0263-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 04/11/2017] [Indexed: 12/03/2022] Open
Abstract
The molybdenum and tungsten active site model complexes, derived from the protein X-ray crystal structure of the first W-containing nitrate reductase isolated from Pyrobaculum aerophilum, were computed for nitrate reduction at the COSMO-B3LYP/SDDp//B3LYP/Lanl2DZ(p) energy level of density functional theory. The molybdenum containing active site model complex (Mo–Nar) has the largest activation energy (34.4 kcal/mol) for the oxygen atom transfer from the nitrate to the metal center as compared to the tungsten containing active site model complex (W–Nar) (12.0 kcal/mol). Oxidation of the educt complex is close to thermoneutral (−1.9 kcal/mol) for the Mo active site model complex but strongly exothermic (−34.7 kcal/mol) for the W containing active site model complex, however, the MVI to MIV reduction requires equal amount of reductive power for both metal complexes, Mo–Nar or W–Nar.
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Affiliation(s)
- Uzma Habib
- Research Center for Modeling and Simulation (RCMS), National University of Science and Technology (NUST), H-12, Islamabad, Pakistan.
| | - Matthias Hoffman
- Institute of Inorganic Chemistry, Heidelberg University, Heidelberg, Germany
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16
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Maia LB, Moura I, Moura JJ. Molybdenum and tungsten-containing formate dehydrogenases: Aiming to inspire a catalyst for carbon dioxide utilization. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2016.07.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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17
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Electrochemical evidence that pyranopterin redox chemistry controls the catalysis of YedY, a mononuclear Mo enzyme. Proc Natl Acad Sci U S A 2015; 112:14506-11. [PMID: 26561582 DOI: 10.1073/pnas.1516869112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A long-standing contradiction in the field of mononuclear Mo enzyme research is that small-molecule chemistry on active-site mimic compounds predicts ligand participation in the electron transfer reactions, but biochemical measurements only suggest metal-centered catalytic electron transfer. With the simultaneous measurement of substrate turnover and reversible electron transfer that is provided by Fourier-transformed alternating-current voltammetry, we show that Escherichia coli YedY is a mononuclear Mo enzyme that reconciles this conflict. In YedY, addition of three protons and three electrons to the well-characterized "as-isolated" Mo(V) oxidation state is needed to initiate the catalytic reduction of either dimethyl sulfoxide or trimethylamine N-oxide. Based on comparison with earlier studies and our UV-vis redox titration data, we assign the reversible one-proton and one-electron reduction process centered around +174 mV vs. standard hydrogen electrode at pH 7 to a Mo(V)-to-Mo(IV) conversion but ascribe the two-proton and two-electron transition occurring at negative potential to the organic pyranopterin ligand system. We predict that a dihydro-to-tetrahydro transition is needed to generate the catalytically active state of the enzyme. This is a previously unidentified mechanism, suggested by the structural simplicity of YedY, a protein in which Mo is the only metal site.
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Abstract
Escherichia coli is a versatile facultative anaerobe that can respire on a number of terminal electron acceptors, including oxygen, fumarate, nitrate, and S- and N-oxides. Anaerobic respiration using S- and N-oxides is accomplished by enzymatic reduction of these substrates by dimethyl sulfoxide reductase (DmsABC) and trimethylamine N-oxide reductase (TorCA). Both DmsABC and TorCA are membrane-associated redox enzymes that couple the oxidation of menaquinol to the reduction of S- and N-oxides in the periplasm. DmsABC is membrane bound and is composed of a membrane-extrinsic dimer with a 90.4-kDa catalytic subunit (DmsA) and a 23.1-kDa electron transfer subunit (DmsB). These subunits face the periplasm and are held to the membrane by a 30.8-kDa membrane anchor subunit (DmsC). The enzyme provides the scaffold for an electron transfer relay composed of a quinol binding site, five [4Fe-4S] clusters, and a molybdo-bis(molybdopterin guanine dinucleotide) (present nomenclature: Mo-bis-pyranopterin) (Mo-bisMGD) cofactor. TorCA is composed of a soluble periplasmic subunit (TorA, 92.5 kDa) containing a Mo-bis-MGD. TorA is coupled to the quinone pool via a pentaheme c subunit (TorC, 40.4 kDa) in the membrane. Both DmsABC and TorCA require system-specific chaperones (DmsD or TorD) for assembly, cofactor insertion, and/or targeting to the Tat translocon. In this chapter, we discuss the complex regulation of the dmsABC and torCAD operons, the poorly understood paralogues, and what is known about the assembly and translocation to the periplasmic space by the Tat translocon.
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Okamura TA, Okamura ATA, Omi Y, Fujii M, Tatsumi M, Onitsuka K. Significant differences of monooxotungsten(IV) and dioxotungsten(VI) benzenedithiolates containing two intramolecular NHS hydrogen bonds from molybdenum analogues. Dalton Trans 2015; 44:18090-100. [PMID: 26417921 DOI: 10.1039/c5dt03278d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A monooxotungsten(iv) benzenedithiolate complex containing two intramolecular NHS hydrogen bonds, (NEt4)2[W(IV)O(1,2-S2-3-t-BuNHCOC6H3)2] (1-W), was synthesized via a ligand-exchange reaction between a new starting complex, (NEt4)2[W(IV)O(SC6F5)4], and a partially deprotonated dithiol. When dithiol was used in solution, the oxo ligand was protonated and removed to afford (NEt4)2[W(IV)(1,2-S2-3-t-BuNHCOC6H3)3]. The trans isomer, trans-1-W, was crystallized, and the molecular structure was determined via X-ray analysis. Trans-1-W was gradually isomerized by heating it in solution and it eventually achieved an approximately 1 : 1 mixture of trans/cis isomers after 48 days. However, a slightly excess amount of trans isomer remained, so the isomerization rate was considerably slower than that of the molybdenum analogue. In the presence of NEt4BH4, deuteration of the NH protons was observed in acetonitrile-d3. The oxidation of both trans- and cis-1-W by Me3NO afforded the corresponding dioxotungsten(vi) complex, (NEt4)2[W(VI)O2(1,2-S2-3-t-BuNHCOC6H3)2] (2-W), as a single isomer. The contributions of the NHS hydrogen bonds to the bond distances, vibrational data, and electrochemical properties are described via comparisons with their molybdenum analogues. The results of this comparative study yielded insights into both tungsten and molybdenum enzymes.
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Affiliation(s)
| | - A Taka-Aki Okamura
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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Molybdenum Availability in the Ecosystems (Geochemistry Aspects, When and How Did It Appear?). SPRINGERBRIEFS IN MOLECULAR SCIENCE 2015. [DOI: 10.1007/978-94-017-9972-0_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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21
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Molybdenum and tungsten-dependent formate dehydrogenases. J Biol Inorg Chem 2014; 20:287-309. [DOI: 10.1007/s00775-014-1218-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 11/09/2014] [Indexed: 11/25/2022]
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22
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Valdez CE, Smith QA, Nechay MR, Alexandrova AN. Mysteries of metals in metalloenzymes. Acc Chem Res 2014; 47:3110-7. [PMID: 25207938 DOI: 10.1021/ar500227u] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Natural metalloenzymes are often the most proficient catalysts in terms of their activity, selectivity, and ability to operate at mild conditions. However, metalloenzymes are occasionally surprising in their selection of catalytic metals, and in their responses to metal substitution. Indeed, from the isolated standpoint of producing the best catalyst, a chemist designing from first-principles would likely choose a different metal. For example, some enzymes employ a redox active metal where a simple Lewis acid is needed. Such are several hydrolases. In other cases, substitution of a non-native metal leads to radical improvements in reactivity. For example, histone deacetylase 8 naturally operates with Zn(2+) in the active site but becomes much more active with Fe(2+). For β-lactamases, the replacement of the native Zn(2+) with Ni(2+) was suggested to lead to higher activity as predicted computationally. There are also intriguing cases, such as Fe(2+)- and Mn(2+)-dependent ribonucleotide reductases and W(4+)- and Mo(4+)-dependent DMSO reductases, where organisms manage to circumvent the scarcity of one metal (e.g., Fe(2+)) by creating protein structures that utilize another metal (e.g., Mn(2+)) for the catalysis of the same reaction. Naturally, even though both metal forms are active, one of the metals is preferred in every-day life, and the other metal variant remains dormant until an emergency strikes in the cell. These examples lead to certain questions. When are catalytic metals selected purely for electronic or structural reasons, implying that enzymatic catalysis is optimized to its maximum? When are metal selections a manifestation of competing evolutionary pressures, where choices are dictated not just by catalytic efficiency but also by other factors in the cell? In other words, how can enzymes be improved as catalysts merely through the use of common biological building blocks available to cells? Addressing these questions is highly relevant to the enzyme design community, where the goal is to prepare maximally efficient quasi-natural enzymes for the catalysis of reactions that interest humankind. Due to competing evolutionary pressures, many natural enzymes may not have evolved to be ideal catalysts and can be improved for the isolated purpose of catalysis in vitro when the competing factors are removed. The goal of this Account is not to cover all the possible stories but rather to highlight how variable enzymatic catalysis can be. We want to bring up possible factors affecting the evolution of enzyme structure, and the large- and intermediate-scale structural and electronic effects that metals can induce in the protein, and most importantly, the opportunities for optimization of these enzymes for catalysis in vitro.
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Affiliation(s)
- Crystal E. Valdez
- Department
of Chemistry and Biochemistry, and ‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Quentin A. Smith
- Department
of Chemistry and Biochemistry, and ‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Michael R. Nechay
- Department
of Chemistry and Biochemistry, and ‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Anastassia N. Alexandrova
- Department
of Chemistry and Biochemistry, and ‡California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
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Abstract
In microaerophilic or anaerobic environments, Pseudomonas aeruginosa utilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO4 (2-)). Here, we show that molybdate acquisition in P. aeruginosa occurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of the modA gene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition of P. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth of P. aeruginosa and reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition.
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Blomberg MRA, Borowski T, Himo F, Liao RZ, Siegbahn PEM. Quantum chemical studies of mechanisms for metalloenzymes. Chem Rev 2014; 114:3601-58. [PMID: 24410477 DOI: 10.1021/cr400388t] [Citation(s) in RCA: 431] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
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25
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Hartmann T, Leimkühler S. The oxygen-tolerant and NAD+-dependent formate dehydrogenase from Rhodobacter capsulatus is able to catalyze the reduction of CO2 to formate. FEBS J 2013; 280:6083-96. [PMID: 24034888 DOI: 10.1111/febs.12528] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/08/2013] [Accepted: 09/10/2013] [Indexed: 11/27/2022]
Abstract
The formate dehydrogenase from Rhodobacter capsulatus (RcFDH) is an oxygen-tolerant protein with an (αβγ)2 subunit composition that is localized in the cytoplasm. It belongs to the group of metal and NAD(+)-dependent FDHs with the coordination of a molybdenum cofactor, four [Fe4S4] clusters and one [Fe2S2] cluster associated with the α-subunit, one [Fe4S4] cluster and one FMN bound to the β-subunit, and one [Fe2S2] cluster bound to the γ-subunit. RcFDH was heterologously expressed in Escherichia coli and characterized. Cofactor analysis showed that the bis-molybdopterin guanine dinucleotide cofactor is bound to the FdsA subunit containing a cysteine ligand at the active site. A turnover rate of 2189 min(-1) with formate as substrate was determined. The back reaction for the reduction of CO2 was catalyzed with a k(cat) of 89 min(-1). The preference for formate oxidation shows an energy barrier for CO2 reduction of the enzyme. Furthermore, the FMN-containing and [Fe4S4]-containing β-subunit together with the [Fe2S2]-containing γ-subunit forms a diaphorase unit with activities for both NAD(+) reduction and NADH oxidation. In addition to the structural genes fdsG, fdsB, and fdsA, the fds operon in R. capsulatus contains the fdsC and fdsD genes. Expression studies showed that RcFDH is only active when both FdsC and FdsD are present. Both proteins are proposed to be involved in bis-molybdopterin guanine dinucleotide modification and insertion into RcFDH.
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Affiliation(s)
- Tobias Hartmann
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Germany
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26
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Why is the molybdenum-substituted tungsten-dependent formaldehyde ferredoxin oxidoreductase not active? A quantum chemical study. J Biol Inorg Chem 2013; 18:175-181. [PMID: 23183892 DOI: 10.1007/s00775-012-0961-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/13/2012] [Indexed: 01/12/2023]
Abstract
Formaldehyde ferredoxin oxidoreductase is a tungsten-dependent enzyme that catalyzes the oxidative degradation of formaldehyde to formic acid. The molybdenum ion can be incorporated into the active site to displace the tungsten ion, but is without activity. Density functional calculations have been employed to understand the incapacitation of the enzyme caused by molybdenum substitution. The calculations show that the enzyme with molybdenum (Mo-FOR) has higher redox potential than that with tungsten, which makes the formation of the Mo(VI)=O complex endothermic by 14 kcal/mol. Following our previously suggested mechanism for this enzyme, the formaldehyde substrate oxidation was also investigated for Mo-FOR using the same quantum-mechanics-only model, except for the displacement of tungsten by molybdenum. The calculations demonstrate that formaldehyde oxidation occurs via a sequential two-step mechanism. Similarly to the tungsten-catalyzed reaction, the Mo(VI)=O species performs the nucleophilic attack on the formaldehyde carbon, followed by proton transfer in concert with two-electron reduction of the metal center. The first step is rate-limiting, with a total barrier of 28.2 kcal/mol. The higher barrier is mainly due to the large energy penalty for the formation of the Mo(VI)=O species.
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The prokaryotic Mo/W-bisPGD enzymes family: a catalytic workhorse in bioenergetic. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1048-85. [PMID: 23376630 DOI: 10.1016/j.bbabio.2013.01.011] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 01/21/2013] [Accepted: 01/23/2013] [Indexed: 01/05/2023]
Abstract
Over the past two decades, prominent importance of molybdenum-containing enzymes in prokaryotes has been put forward by studies originating from different fields. Proteomic or bioinformatic studies underpinned that the list of molybdenum-containing enzymes is far from being complete with to date, more than fifty different enzymes involved in the biogeochemical nitrogen, carbon and sulfur cycles. In particular, the vast majority of prokaryotic molybdenum-containing enzymes belong to the so-called dimethylsulfoxide reductase family. Despite its extraordinary diversity, this family is characterized by the presence of a Mo/W-bis(pyranopterin guanosine dinucleotide) cofactor at the active site. This review highlights what has been learned about the properties of the catalytic site, the modular variation of the structural organization of these enzymes, and their interplay with the isoprenoid quinones. In the last part, this review provides an integrated view of how these enzymes contribute to the bioenergetics of prokaryotes. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems.
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28
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Liao RZ, Yu JG, Himo F. Tungsten-dependent formaldehyde ferredoxin oxidoreductase: Reaction mechanism from quantum chemical calculations. J Inorg Biochem 2011; 105:927-36. [DOI: 10.1016/j.jinorgbio.2011.03.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/25/2011] [Accepted: 03/28/2011] [Indexed: 11/30/2022]
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29
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Magalon A, Fedor JG, Walburger A, Weiner JH. Molybdenum enzymes in bacteria and their maturation. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2010.12.031] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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30
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Holm RH, Solomon EI, Majumdar A, Tenderholt A. Comparative molecular chemistry of molybdenum and tungsten and its relation to hydroxylase and oxotransferase enzymes. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2010.10.017] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Tungsten and molybdenum regulation of formate dehydrogenase expression in Desulfovibrio vulgaris Hildenborough. J Bacteriol 2011; 193:2909-16. [PMID: 21498650 DOI: 10.1128/jb.00042-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Formate is an important energy substrate for sulfate-reducing bacteria in natural environments, and both molybdenum- and tungsten-containing formate dehydrogenases have been reported in these organisms. In this work, we studied the effect of both metals on the levels of the three formate dehydrogenases encoded in the genome of Desulfovibrio vulgaris Hildenborough, with lactate, formate, or hydrogen as electron donors. Using Western blot analysis, quantitative real-time PCR, activity-stained gels, and protein purification, we show that a metal-dependent regulatory mechanism is present, resulting in the dimeric FdhAB protein being the main enzyme present in cells grown in the presence of tungsten and the trimeric FdhABC₃ protein being the main enzyme in cells grown in the presence of molybdenum. The putatively membrane-associated formate dehydrogenase is detected only at low levels after growth with tungsten. Purification of the three enzymes and metal analysis shows that FdhABC₃ specifically incorporates Mo, whereas FdhAB can incorporate both metals. The FdhAB enzyme has a much higher catalytic efficiency than the other two. Since sulfate reducers are likely to experience high sulfide concentrations that may result in low Mo bioavailability, the ability to use W is likely to constitute a selective advantage.
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32
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Ferroni FM, Rivas MG, Rizzi AC, Lucca ME, Perotti NI, Brondino CD. Nitrate reduction associated with respiration in Sinorhizobium meliloti 2011 is performed by a membrane-bound molybdoenzyme. Biometals 2011; 24:891-902. [PMID: 21432624 DOI: 10.1007/s10534-011-9442-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
Abstract
The purification and biochemical characterization of the respiratory membrane-bound nitrate reductase from Sinorhizobium meliloti 2011 (Sm NR) is reported together with the optimal conditions for cell growth and enzyme production. The best biomass yield was obtained under aerobic conditions in a fed-batch system using Luria-Bertani medium with glucose as carbon source. The highest level of Sm NR production was achieved using microaerobic conditions with the medium supplemented with both nitrate and nitrite. Sm NR is a mononuclear Mo-protein belonging to the DMSO reductase family isolated as a heterodimeric enzyme containing two subunits of 118 and 45 kDa. Protein characterization by mass spectrometry showed homology with respiratory nitrate reductases. UV-Vis spectra of as-isolated and dithionite reduced Sm NR showed characteristic absorption bands of iron-sulfur and heme centers. Kinetic studies indicate that Sm NR follows a Michaelis-Menten mechanism (K (m) = 97 ± 11 μM, V = 9.4 ± 0.5 μM min(-1), and k (cat) = 12.1 ± 0.6 s(-1)) and is inhibited by azide, chlorate, and cyanide with mixed inhibition patterns. Physiological and kinetic studies indicate that molybdenum is essential for NR activity and that replacement of this metal for tungsten inhibits the enzyme. Although no narGHI gene cluster has been annotated in the genome of rhizobia, the biochemical characterization indicates that Sm NR is a Mo-containing NR enzyme with molecular organization similar to NarGHI.
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Affiliation(s)
- Felix M Ferroni
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina
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33
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Gates AJ, Kemp GL, To CY, Mann J, Marritt SJ, Mayes AG, Richardson DJ, Butt JN. The relationship between redox enzyme activity and electrochemical potential—cellular and mechanistic implications from protein film electrochemistry. Phys Chem Chem Phys 2011; 13:7720-31. [DOI: 10.1039/c0cp02887h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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de Vries S, Momcilovic M, Strampraad MJF, Whitelegge JP, Baghai A, Schröder I. Adaptation to a high-tungsten environment: Pyrobaculum aerophilum contains an active tungsten nitrate reductase. Biochemistry 2010; 49:9911-21. [PMID: 20863064 DOI: 10.1021/bi100974v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitrate reductases (Nars) belong to the DMSO reductase family of molybdoenzymes. The hyperthermophilic denitrifying archaeon Pyrobaculum aerophilum exhibits nitrate reductase (Nar) activity even at WO(4)(2-) concentrations that are inhibitory to bacterial Nars. In this report, we establish that the enzyme purified from cells grown with 4.5 μM WO(4)(2-) contains W as the metal cofactor but is otherwise identical to the Mo-Nar previously purified from P. aerophilum grown at low WO(4)(2-) concentrations. W is coordinated by a bis-molybdopterin guanine dinucleotide cofactor. The W-Nar has a 2-fold lower turnover number (633 s(-1)) but the same K(m) value for nitrate (56 μM) as the Mo-Nar. Quinol reduction and nitrate oxidation experiments monitored by EPR with both pure W-Nar and mixed W- and Mo-Nar preparations suggest a monodentate ligation by the conserved Asp241 for W(V), while Asp241 acts as a bidentate ligand for Mo(V). Redox titrations of the Mo-Nar revealed a midpoint potential of 88 mV for Mo(V/IV). The E(m) for W(V/IV) of the purified W-Nar was estimated to be -8 mV. This relatively small difference in midpoint potential is consistent with comparable enzyme activities of W- and Mo-Nars. Unlike bacterial Nars, the P. aerophilum Nar contains a unique membrane anchor, NarM, with a single heme of the o(P) type (E(m) = 126 mV). In contrast to bacterial Nars, the P. aerophilum Nar faces the cell's exterior and, hence, does not contribute to the proton motive force. Formate is used as a physiological electron donor. This is the first description of an active W-containing Nar demonstrating the unique ability of hyperthermophiles to adapt to their high-WO(4)(2-) environment.
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Affiliation(s)
- Simon de Vries
- Laboratory of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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35
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Thermostable properties of the periplasmic selenate reductase from Thauera selenatis. Biochimie 2010; 92:1268-73. [DOI: 10.1016/j.biochi.2010.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 06/04/2010] [Indexed: 11/18/2022]
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36
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Taveirne ME, Sikes ML, Olson JW. Molybdenum and tungsten in Campylobacter jejuni: their physiological role and identification of separate transporters regulated by a single ModE-like protein. Mol Microbiol 2010; 74:758-71. [PMID: 19919002 DOI: 10.1111/j.1365-2958.2009.06901.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Campylobacter jejuni is an important human pathogen that causes millions of cases of food-borne enteritis each year. The C. jejuni respiratory chain is highly branched and contains at least four enzymes predicted to contain a metal binding pterin (MPT), with the metal being either molybdenum or tungsten. Also predicted are two separate transport systems, one for molybdenum encoded by modABC and a second for tungsten encoded by tupABC. Both transport systems were mutated and the activities of the four predicted MPT-containing enzymes were assayed in the presence of molybdenum and tungsten in wild-type and mod and tup backgrounds. Results indicate that mod is primarily a molybdenum transporter that can also transport tungsten, while tup is a tungsten-specific transporter. The MPT containing enzymes nitrate reductase, sulphite oxidase, and SN oxide reductase are strict molybdoenzymes while formate dehydrogenase prefers tungsten. A ModE-like protein regulates both transporters, repressing mod in the presence of both molybdenum and tungsten and tup only in the presence of tungsten. Like other ModE proteins, the C. jejuni ModE binds DNA through a helix-turn-helix DNA binding domain, but unlike other members of the ModE family it does not have a metal binding domain.
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Affiliation(s)
- Michael E Taveirne
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695, USA
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37
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Smart JP, Cliff MJ, Kelly DJ. A role for tungsten in the biology of Campylobacter jejuni: tungstate stimulates formate dehydrogenase activity and is transported via an ultra-high affinity ABC system distinct from the molybdate transporter. Mol Microbiol 2009; 74:742-57. [PMID: 19818021 DOI: 10.1111/j.1365-2958.2009.06902.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The food-borne pathogen Campylobacter jejuni possesses no known tungstoenzymes, yet encodes two ABC transporters (Cj0300-0303 and Cj1538-1540) homologous to bacterial molybdate (ModABC) uptake systems and the tungstate transporter (TupABC) of Eubacterium acidaminophilum respectively. The actual substrates and physiological role of these transporters were investigated. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry of the purified periplasmic binding proteins of each system revealed that while Cj0303 is unable to discriminate between molybdate and tungstate (K(D) values for both ligands of 4-8 nM), Cj1540 binds tungstate with a K(D) of 1.0 +/- 0.2 pM; 50 000-fold more tightly than molybdate. Induction-coupled plasma mass spectroscopy of single and double mutants showed that this large difference in affinity is reflected in a lower cellular tungsten content in a cj1540 (tupA) mutant compared with a cj0303c (modA) mutant. Surprisingly, formate dehydrogenase (FDH) activity was decreased approximately 50% in the tupA strain, and supplementation of the growth medium with tungstate significantly increased FDH activity in the wild type, while inhibiting known molybdoenzymes. Our data suggest that C. jejuni possesses a specific, ultra-high affinity tungstate transporter that supplies tungsten for incorporation into FDH. Furthermore, possession of two MoeA paralogues may explain the formation of both molybdopterin and tungstopterin in this bacterium.
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Affiliation(s)
- Jonathan P Smart
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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39
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Regulski EE, Moy RH, Weinberg Z, Barrick JE, Yao Z, Ruzzo WL, Breaker RR. A widespread riboswitch candidate that controls bacterial genes involved in molybdenum cofactor and tungsten cofactor metabolism. Mol Microbiol 2008; 68:918-32. [PMID: 18363797 PMCID: PMC2408646 DOI: 10.1111/j.1365-2958.2008.06208.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have identified a highly conserved RNA motif located upstream of genes encoding molybdate transporters, molybdenum cofactor (Moco) biosynthesis enzymes, and proteins that utilize Moco as a coenzyme. Bioinformatics searches have identified 176 representatives in γ-Proteobacteria, δ-Proteobacteria, Clostridia, Actinobacteria, Deinococcus-Thermus species and DNAs from environmental samples. Using genetic assays, we demonstrate that a Moco RNA in Escherichia coli associated with the Moco biosynthetic operon controls gene expression in response to Moco production. In addition, we provide evidence indicating that this conserved RNA discriminates against closely related analogues of Moco. These results, together with extensive phylogenetic conservation and typical gene control structures near some examples, indicate that representatives of this structured RNA represent a novel class of riboswitches that sense Moco. Furthermore, we identify variants of this RNA that are likely to be triggered by the related tungsten cofactor (Tuco), which carries tungsten in place of molybdenum as the metal constituent.
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Affiliation(s)
- Elizabeth E Regulski
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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40
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A novel caffeine dehydrogenase in Pseudomonas sp. strain CBB1 oxidizes caffeine to trimethyluric acid. J Bacteriol 2007; 190:772-6. [PMID: 17981969 DOI: 10.1128/jb.01390-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A unique heterotrimeric caffeine dehydrogenase was purified from Pseudomonas sp. strain CBB1. This enzyme oxidized caffeine to trimethyluric acid stoichiometrically and hydrolytically, without producing hydrogen peroxide. The enzyme was not NAD(P)(+) dependent; coenzyme Q(0) was the preferred electron acceptor. The enzyme was specific for caffeine and theobromine and showed no activity with xanthine.
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41
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Park MO, Mizutani T, Jones PR. Glyceraldehyde-3-phosphate ferredoxin oxidoreductase from Methanococcus maripaludis. J Bacteriol 2007; 189:7281-9. [PMID: 17704226 PMCID: PMC2168465 DOI: 10.1128/jb.00828-07] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome sequence of the non-sugar-assimilating mesophile Methanococcus maripaludis contains three genes encoding enzymes: a nonphosphorylating NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR); all these enzymes are potentially capable of catalyzing glyceraldehyde-3-phosphate (G3P) metabolism. GAPOR, whose homologs have been found mainly in archaea, catalyzes the reduction of ferredoxin coupled with oxidation of G3P. GAPOR has previously been isolated and characterized only from a sugar-assimilating hyperthermophile, Pyrococcus furiosus (GAPOR(Pf)), and contains the rare metal tungsten as an irreplaceable cofactor. Active recombinant M. maripaludis GAPOR (GAPOR(Mm)) was purified from Escherichia coli grown in minimal medium containing 100 muM sodium molybdate. In contrast, GAPOR(Mm) obtained from cells grown in medium containing tungsten (W) and W and molybdenum (Mo) or in medium without added W and Mo did not display any activity. Activity and transcript analysis of putative G3P-metabolizing enzymes and corresponding genes were performed with M. maripaludis cultured under autotrophic conditions in chemically defined medium. The activity of GAPOR(Mm) was constitutive throughout the culture period and exceeded that of GAPDH at all time points. As GAPDH activity was detected in only the gluconeogenic direction and GAPN activity was completely absent, only GAPOR(Mm) catalyzes oxidation of G3P in M. maripaludis. Recombinant GAPOR(Mm) is posttranscriptionally regulated as it exhibits pronounced and irreversible substrate inhibition and is completely inhibited by 1 muM ATP. With support from flux balance analysis, it is concluded that the major physiological role of GAPOR(Mm) in M. maripaludis most likely involves only nonoptimal growth conditions.
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Affiliation(s)
- Myong-Ok Park
- Research and Development Division, Fujirebio Inc, Hachioji-shi, Tokyo, Japan
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42
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Hofmann M. Density functional theory studies of model complexes for molybdenum-dependent nitrate reductase active sites. J Biol Inorg Chem 2007; 12:989-1001. [PMID: 17636351 DOI: 10.1007/s00775-007-0271-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 06/11/2007] [Indexed: 11/25/2022]
Abstract
Molybdenum and tungsten complexes as models for the active sites of assimilatory or dissimilatory nitrate reductases (NR) were computed at the CPCM-B98/SDDp//B3LYP/Lanl2DZp* plus zero point energy level of density functional theory. The ligands were chosen on the basis of available experimental protein or small chemical model structures. A water molecule is found to bind to assimilatory NR models [(Me(2)C(2)S(2))MO(YMe)](-) (-11.5 kcal mol(-1) for M is Mo, Y is S) and may be replaced by nitrate (-4.5 kcal mol(-1)) (but a hydroxy group may not). Nature's choice of M is Mo and Y is S for NR has the largest activation energy for protein-free models (13.3 kcal mol(-1)) and the least exothermic reaction energy for the nitrate reduction (-14.9 kcal mol(-1)) compared with M is W and Y is O or Se alternatives. Water binding to dissimilatory NR model complexes [(Me(2)C(2)S(2))(2)M(YR)](-) is considerably endothermic (10.3 kcal mol(-1)); nitrate binding is only slightly so (1.5 kcal mol(-1) for RY(-) is MeS(-)). The exchange of an oxo ligand (assimilatory NR) for a dithiolato ligand (dissimilatory NR model) reduces the exothermicity (-8.6 kcal mol(-1) relative to the fivefold-coordinate reduced complex) and raises the barrier for oxygen atom transfer (OAT) in the nitrate complex (19.2 kcal mol(-1)). Not for the mono but only for the bisdithiolato complexes hydrogen bonding involving the coordinated substrate may significantly lower the OAT barrier as shown by explicitly adding water molecules. Substitution of tungsten for molybdenum generally lowers OAT activation energies and makes nitrate reduction reaction energies more negative. Bidentate carboxylato binding identified in Escherichia coli NarGHI is the preferred binding mode also for an acetato model. However, one dithiolato ligand folds when the Mo(VI) center is bare of a good pi-donor ligand, e.g., an oxo group. Computations on [(mnt)(2)Mo(IV)(YR)(PPh(3))](-) [mnt is (CN)(2)C(2)S(2) (2-)] gave a smaller nitrate reduction activation energy for RY(-) is Cl(-), compared with RY(-) is PhS(-), although experimentally only the phenyl thiolato complex and not the chloro complex was found to be a functional NR model.
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Affiliation(s)
- Matthias Hofmann
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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43
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Dridge EJ, Richardson DJ, Lewis RJ, Butler CS. Developing structure-based models to predict substrate specificity of D-group (Type II) molybdenum enzymes: application to a molybdo-enzyme of unknown function from Archaeoglobus fulgidus. Biochem Soc Trans 2006; 34:118-21. [PMID: 16417498 DOI: 10.1042/bst0340118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The AF0174-AF0176 gene cluster in Archaeoglobus fulgidus encodes a putative oxyanion reductase of the D-type (Type II) family of molybdo-enzymes. Sequence analysis reveals that the catalytic subunit AF0176 shares low identity (31-32%) and similarity (41-42%) to both NarG and SerA, the catalytic components of the respiratory nitrate and selenate reductases respectively. Consequently, predicting the oxyanion substrate selectivity of AF0176 has proved difficult based solely on sequence alignments. In the present study, we have modelled both AF0176 and SerA on the recently determined X-ray structure of the NAR (nitrate reductase) from Escherichia coli and have identified a number of key amino acid residues, conserved in all known NAR sequences, including AF0176, that we speculate may enhance selectivity towards trigonal planar (NO(3)(-)) rather than tetrahedral (SeO(4)(2-) and ClO(4)(-)) substrates.
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Affiliation(s)
- E J Dridge
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
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44
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Morozkina EV, Nosikov AN, Zvyagilskaya RA, L'vov NP. Isolation, Purification, and Characterization of Nitrate Reductase from a Salt-Tolerant Rhodotorula glutinis Yeast Strain Grown in the Presence of Tungsten. BIOCHEMISTRY (MOSCOW) 2005; 70:809-14. [PMID: 16097946 DOI: 10.1007/s10541-005-0188-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The salt-tolerant Rhodotorula glutinis yeast strain grew in medium containing nitrate, 1 mM tungsten, and trace amounts of molybdenum (as impurities from the reagents used). Isolation of electrophoretically homogenous preparation of nitrate reductase from the Rh. glutinis cells grown under these growth conditions is described. The isolated nitrate reductase is a molybdenum-containing homodimer with molecular mass of 130 kD, containing 0.177 mol of Mo per mol of the enzyme. The activity of the enzyme is maximal at pH 7.0 and 35-45 degrees C and is inhibited by low concentrations of azide and cyanide. The enzyme is almost insensitive to 1 mM tungsten.
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Affiliation(s)
- E V Morozkina
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia.
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45
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Cabello P, Roldán MD, Moreno-Vivián C. Nitrate reduction and the nitrogen cycle in archaea. MICROBIOLOGY-SGM 2005; 150:3527-3546. [PMID: 15528644 DOI: 10.1099/mic.0.27303-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The nitrogen cycle (N-cycle) in the biosphere, mainly driven by prokaryotes, involves different reductive or oxidative reactions used either for assimilatory purposes or in respiratory processes for energy conservation. As the N-cycle has important agricultural and environmental implications, bacterial nitrogen metabolism has become a major research topic in recent years. Archaea are able to perform different reductive pathways of the N-cycle, including both assimilatory processes, such as nitrate assimilation and N(2) fixation, and dissimilatory reactions, such as nitrate respiration and denitrification. However, nitrogen metabolism is much less known in archaea than in bacteria. The availability of the complete genome sequences of several members of the eury- and crenarchaeota has enabled new approaches to the understanding of archaeal physiology and biochemistry, including metabolic reactions involving nitrogen compounds. Comparative studies reveal that significant differences exist in the structure and regulation of some enzymes involved in nitrogen metabolism in archaea, giving rise to important conclusions and new perspectives regarding the evolution, function and physiological relevance of the different N-cycle processes. This review discusses the advances that have been made in understanding nitrate reduction and other aspects of the inorganic nitrogen metabolism in archaea.
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Affiliation(s)
- Purificación Cabello
- Departamento de Biología Vegetal, Área de Fisiología Vegetal, Universidad de Córdoba, Spain
| | - M Dolores Roldán
- Departamento de Bioquímica y Biología Molecular, Edificio Severo Ochoa, 1a planta, Campus Universitario de Rabanales, Universidad de Córdoba, 14071-Córdoba, Spain
| | - Conrado Moreno-Vivián
- Departamento de Bioquímica y Biología Molecular, Edificio Severo Ochoa, 1a planta, Campus Universitario de Rabanales, Universidad de Córdoba, 14071-Córdoba, Spain
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46
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Nichols JD, Rajagopalan KV. In vitro molybdenum ligation to molybdopterin using purified components. J Biol Chem 2005; 280:7817-22. [PMID: 15632135 DOI: 10.1074/jbc.m413783200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that Escherichia coli MoeA and MogA are required in vivo for the final step of molybdenum cofactor biosynthesis, the addition of the molybdenum atom to the dithiolene of molybdopterin. MoeA was also shown to facilitate the addition of molybdenum in an assay using crude extracts from E. coli moeA(-) cells. The experiments detailed in this report utilized an in vitro assay for MoeA-mediated molybdenum ligation to de novo synthesized molybdopterin using only purified components and monitoring the reconstitution of human aposulfite oxidase. In this assay, maximum activation was achieved by delaying the addition of aposulfite oxidase to allow for adequate molybdenum coordination to occur. Tungsten, which substitutes for molybdenum in hyperthermophilic organisms, could also be ligated to molybdopterin using this system, though not as efficiently as molybdenum. Addition of thiol compounds to the assay inhibited activity. Addition of MogA also inhibited the reaction. However, in the presence of ATP and magnesium, addition of MogA to the assay increased the level of aposulfite oxidase reconstitution beyond that observed with MoeA alone. This effect was not observed in the absence of MoeA. The results presented here demonstrate that MoeA is responsible for mediating molybdenum ligation to molybdopterin, whereas MogA stimulates this activity in an ATP-dependent manner.
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Affiliation(s)
- Jason D Nichols
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Vergnes A, Gouffi-Belhabich K, Blasco F, Giordano G, Magalon A. Involvement of the Molybdenum Cofactor Biosynthetic Machinery in the Maturation of the Escherichia coli Nitrate Reductase A. J Biol Chem 2004; 279:41398-403. [PMID: 15247236 DOI: 10.1074/jbc.m407087200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The maturation of Escherichia coli nitrate reductase A requires the incorporation of the Mo-(bis-MGD) cofactor to the apoprotein. For this process, the NarJ chaperone is strictly required. We report the first description of protein interactions between molybdenum cofactor biosynthetic proteins (MogA, MoeA, MobA, and MobB) and the aponitrate reductase (NarG) using a bacterial two-hybrid approach. Two conditions have to be satisfied to allow the visualization of the interactions, (i) the presence of an active and mature molybdenum cofactor and (ii) the presence of the NarJ chaperone and of the NarG structural partner subunit, NarH. Formation of tungsten-substituted cofactor prevents the interaction between NarG and the four biosynthetic proteins. Our results suggested that the final stages of molybdenum cofactor biosynthesis occur on a complex made up by MogA, MoeA, MobA, and MobB, which is also in charge with the delivery of the mature cofactor onto the aponitrate reductase A in a NarJ-assisted process.
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Affiliation(s)
- Alexandra Vergnes
- Laboratoire de Chimie Bactérienne, Institut Biologie Structurale et Microbiologie, CNRS 31, chemin Joseph Aiguier cedex 09, 13402 Marseille, France
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48
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Loschi L, Brokx SJ, Hills TL, Zhang G, Bertero MG, Lovering AL, Weiner JH, Strynadka NCJ. Structural and biochemical identification of a novel bacterial oxidoreductase. J Biol Chem 2004; 279:50391-400. [PMID: 15355966 DOI: 10.1074/jbc.m408876200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By using a bioinformatics screen of the Escherichia coli genome for potential molybdenum-containing enzymes, we have identified a novel oxidoreductase conserved in the majority of Gram-negative bacteria. The identified operon encodes for a proposed heterodimer, YedYZ in Escherichia coli, consisting of a soluble catalytic subunit termed YedY, which is likely anchored to the membrane by a heme-containing trans-membrane subunit termed YedZ. YedY is uniquely characterized by the presence of one molybdenum molybdopterin not conjugated by an additional nucleotide, and it represents the only molybdoenzyme isolated from E. coli characterized by the presence of this cofactor form. We have further characterized the catalytic subunit YedY in both the molybdenum- and tungsten-substituted forms by using crystallographic analysis. YedY is very distinct in overall architecture from all known bacterial reductases but does show some similarity with the catalytic domain of the eukaryotic chicken liver sulfite oxidase. However, the strictly conserved residues involved in the metal coordination sphere and in the substrate binding pocket of YedY are strikingly different from that of chicken liver sulfite oxidase, suggesting a catalytic activity more in keeping with a reductase than that of a sulfite oxidase. Preliminary kinetic analysis of YedY with a variety of substrates supports our proposal that YedY and its many orthologues may represent a new type of membrane-associated bacterial reductase.
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Affiliation(s)
- Lodovica Loschi
- Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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49
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Moura JJG, Brondino CD, Trincão J, Romão MJ. Mo and W bis-MGD enzymes: nitrate reductases and formate dehydrogenases. J Biol Inorg Chem 2004; 9:791-9. [PMID: 15311335 DOI: 10.1007/s00775-004-0573-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Accepted: 06/14/2004] [Indexed: 10/26/2022]
Abstract
Molybdenum and tungsten are second- and third-row transition elements, respectively, which are found in a mononuclear form in the active site of a diverse group of enzymes that generally catalyze oxygen atom transfer reactions. Mononuclear Mo-containing enzymes have been classified into three families: xanthine oxidase, DMSO reductase, and sulfite oxidase. The proteins of the DMSO reductase family present the widest diversity of properties among its members and our knowledge about this family was greatly broadened by the study of the enzymes nitrate reductase and formate dehydrogenase, obtained from different sources. We discuss in this review the information of the better characterized examples of these two types of Mo enzymes and W enzymes closely related to the members of the DMSO reductase family. We briefly summarize, also, the few cases reported so far for enzymes that can function either with Mo or W at their active site.
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Affiliation(s)
- José J G Moura
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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50
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Enemark JH, Cooney JJA, Wang JJ, Holm RH. Synthetic Analogues and Reaction Systems Relevant to the Molybdenum and Tungsten Oxotransferases. Chem Rev 2003; 104:1175-200. [PMID: 14871153 DOI: 10.1021/cr020609d] [Citation(s) in RCA: 424] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- John H Enemark
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
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