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Schulte NB, Pushie MJ, Martinez A, Sendzik M, Escobedo M, Kuter K, Haas KL. Exploration of the Potential Role of Serum Albumin in the Delivery of Cu(I) to Ctr1. Inorg Chem 2023; 62:4021-4034. [PMID: 36826341 DOI: 10.1021/acs.inorgchem.2c03753] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Human serum albumin (HSA) is the major copper (Cu) carrier in blood. The majority of previous studies that have investigated Cu interactions with HSA have focused primarily on the Cu(II) oxidation state. Yet, cellular Cu uptake by the human copper transport protein (Ctr1), a plasma membrane-embedded protein responsible for Cu uptake into cells, requires Cu(I). Recent in vitro work has determined that reducing agents, such as the ascorbate present in blood, are sufficient to reduce the Cu(II)HSA complex to form Cu(I)HSA and that Cu(I) is bound to HSA with pM affinity. The biological accessibility of Cu(I)HSA suggests that HSA-bound Cu(I) may be an unappreciated form of Cu cargo and a key player in extracellular Cu trafficking. To better understand Cu trafficking by HSA, we sought to investigate the exchange of Cu(I) from HSA to a model peptide of the Cu-binding ectodomain of Ctr1. In this study, we used X-ray absorption near-edge spectroscopy to show that Cu(I) becomes more highly coordinated as increasing amounts of the Ctr1-14 model peptide are added to a solution of Cu(I)HSA. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to further characterize the interaction of Cu(I)HSA with Ctr1-14 by determining the ligands coordinating Cu(I) and their bond lengths. The EXAFS data support that some Cu(I) likely undergoes complete transfer from HSA to Ctr1-14. This finding of HSA interacting with and releasing Cu(I) to an ectodomain model peptide of Ctr1 suggests a mechanism by which HSA delivers Cu(I) to cells under physiological conditions.
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Affiliation(s)
- Natalie B Schulte
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - M Jake Pushie
- Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Ana Martinez
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Madison Sendzik
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Maria Escobedo
- Department of Mathematics and Computer Science, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Kristin Kuter
- Department of Mathematics and Computer Science, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Kathryn L Haas
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
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2
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Mintmier B, McGarry JM, Bain DJ, Basu P. Kinetic consequences of the endogenous ligand to molybdenum in the DMSO reductase family: a case study with periplasmic nitrate reductase. J Biol Inorg Chem 2020; 26:13-28. [PMID: 33131003 DOI: 10.1007/s00775-020-01833-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/20/2020] [Indexed: 11/24/2022]
Abstract
The molybdopterin enzyme family catalyzes a variety of substrates and plays a critical role in the cycling of carbon, nitrogen, arsenic, and selenium. The dimethyl sulfoxide reductase (DMSOR) subfamily is the most diverse family of molybdopterin enzymes and the members of this family catalyze a myriad of reactions that are important in microbial life processes. Enzymes in the DMSOR family can transform multiple substrates; however, quantitative information about the substrate preference is sparse, and, more importantly, the reasons for the substrate selectivity are not clear. Molybdenum coordination has long been proposed to impact the catalytic activity of the enzyme. Specifically, the molybdenum-coordinating residue may tune substrate preference. As such, molybdopterin enzyme periplasmic nitrate reductase (Nap) is utilized as a vehicle to understand the substrate preference and delineate the kinetic underpinning of the differences imposed by exchanging the molybdenum ligands. To this end, NapA from Campylobacter jejuni has been heterologously overexpressed, and a series of variants, where the molybdenum coordinating cysteine has been replaced with another amino acid, has been produced. The kinetic properties of these variants are discussed and compared with those of the native enzyme, providing quantitative information to understand the function of the molybdenum-coordinating residue.
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Affiliation(s)
- Breeanna Mintmier
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN, 46202, USA
| | - Jennifer M McGarry
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN, 46202, USA
| | - Daniel J Bain
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, IN, 46202, USA.
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3
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Djeghader A, Rossotti M, Abdulkarim S, Biaso F, Gerbaud G, Nitschke W, Schoepp-Cothenet B, Soulimane T, Grimaldi S. Structural evidence for a reaction intermediate mimic in the active site of a sulfite dehydrogenase. Chem Commun (Camb) 2020; 56:9850-9853. [DOI: 10.1039/d0cc03634j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide structural and spectroscopic evidence for a molybdenum–phosphate adduct mimicking a proposed reaction intermediate in the active site of a prokaryotic sulfite oxidizing enzyme.
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Affiliation(s)
- Ahmed Djeghader
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
| | | | - Saleh Abdulkarim
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
| | | | | | | | | | - Tewfik Soulimane
- Department of Chemical Sciences and Bernal Institute
- University of Limerick
- Ireland
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4
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Mintmier B, McGarry JM, Sparacino-Watkins CE, Sallmen J, Fischer-Schrader K, Magalon A, McCormick JR, Stolz JF, Schwarz G, Bain DJ, Basu P. Molecular cloning, expression and biochemical characterization of periplasmic nitrate reductase from Campylobacter jejuni. FEMS Microbiol Lett 2019; 365:5040225. [PMID: 29931366 DOI: 10.1093/femsle/fny151] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/17/2018] [Indexed: 02/07/2023] Open
Abstract
Campylobacter jejuni, a human gastrointestinal pathogen, uses nitrate for growth under microaerophilic conditions using periplasmic nitrate reductase (Nap). The catalytic subunit, NapA, contains two prosthetic groups, an iron sulfur cluster and a molybdenum cofactor. Here we describe the cloning, expression, purification, and Michaelis-Menten kinetics (kcat of 5.91 ± 0.18 s-1 and a KM (nitrate) of 3.40 ± 0.44 μM) in solution using methyl viologen as an electron donor. The data suggest that the high affinity of NapA for nitrate could support growth of C. jejuni on nitrate in the gastrointestinal tract. Site-directed mutagenesis was used and the codon for the molybdenum coordinating cysteine residue has been exchanged for serine. The resulting variant NapA is 4-fold less active than the native enzyme confirming the importance of this residue. The properties of the C. jejuni enzyme reported here represent the first isolation and characterization of an epsilonproteobacterial NapA. Therefore, the fundamental knowledge of Nap has been expanded.
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Affiliation(s)
- Breeanna Mintmier
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA
| | - Jennifer M McGarry
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA
| | | | - Joseph Sallmen
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | | | - Axel Magalon
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, 13402 Marseille, France
| | - Joseph R McCormick
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - John F Stolz
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282, USA
| | - Günter Schwarz
- Institute for Biochemistry, University of Cologne, Cologne 50674, Germany
| | - Daniel J Bain
- Department of Geology and Environmental Science, University of Pittsburgh, PA 15260, USA
| | - Partha Basu
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA
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5
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Maia LB, Moura I, Moura JJ. EPR Spectroscopy on Mononuclear Molybdenum-Containing Enzymes. FUTURE DIRECTIONS IN METALLOPROTEIN AND METALLOENZYME RESEARCH 2017. [DOI: 10.1007/978-3-319-59100-1_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Hahn A, Engelhard C, Reschke S, Teutloff C, Bittl R, Leimkühler S, Risse T. Strukturelle Einblicke in den Mo-Cofaktor-Einbau in Sulfitoxidase durch ortsspezifische Spinmarkierung. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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7
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Hahn A, Engelhard C, Reschke S, Teutloff C, Bittl R, Leimkühler S, Risse T. Structural Insights into the Incorporation of the Mo Cofactor into Sulfite Oxidase from Site‐Directed Spin Labeling. Angew Chem Int Ed Engl 2015; 54:11865-9. [DOI: 10.1002/anie.201504772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 06/29/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Aaron Hahn
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)
| | | | - Stefan Reschke
- Institut für Biochemie und Biologie, Universität Potsdam, Karl‐Liebknecht‐Str. 24‐25, 14476 Golm (Germany)
| | - Christian Teutloff
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
| | - Robert Bittl
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
| | - Silke Leimkühler
- Institut für Biochemie und Biologie, Universität Potsdam, Karl‐Liebknecht‐Str. 24‐25, 14476 Golm (Germany)
| | - Thomas Risse
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)
- Berlin Joint EPR Laboratory Freie Universität Berlin (Germany)
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8
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Alvarez S, Menjón B, Falceto A, Casanova D, Alemany P. Stereochemistry of Complexes with Double and Triple Metal–Ligand Bonds: A Continuous Shape Measures Analysis. Inorg Chem 2014; 53:12151-63. [DOI: 10.1021/ic5021077] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
| | - Babil Menjón
- Instituto de Síntesis
Química y Catálisis Homogénea, CSIC−Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain
| | | | - David Casanova
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), P.K: 1072, 20080 Donostia, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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9
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Pushie MJ, Nienaber KH, McDonald A, Millhauser GL, George GN. Combined EXAFS and DFT structure calculations provide structural insights into the 1:1 multi-histidine complexes of Cu(II) , Cu(I) , and Zn(II) with the tandem octarepeats of the mammalian prion protein. Chemistry 2014; 20:9770-83. [PMID: 25042361 DOI: 10.1002/chem.201304201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 04/06/2014] [Indexed: 02/01/2023]
Abstract
The metal-coordinating properties of the prion protein (PrP) have been the subject of intense focus and debate since the first reports of its interaction with copper just before the turn of the century. The picture of metal coordination to PrP has been improved and refined over the past decade, but structural details of the various metal coordination modes have not been fully elucidated in some cases. In the present study, we have employed X-ray absorption near-edge spectroscopy as well as extended X-ray absorption fine structure (EXAFS) spectroscopy to structurally characterize the dominant 1:1 coordination modes for Cu(II) , Cu(I) , and Zn(II) with an N-terminal fragment of PrP. The PrP fragment corresponds to four tandem repeats representative of the mammalian octarepeat domain, designated as OR4 , which is also the most studied PrP fragment for metal interactions, making our findings applicable to a large body of previous work. Density functional theory (DFT) calculations have provided additional structural and thermodynamic data, and candidate structures have been used to inform EXAFS data analysis. The optimized geometries from DFT calculations have been used to identify potential coordination complexes for multi-histidine coordination of Cu(II) , Cu(I) , and Zn(II) in an aqueous medium, modelled using 4-methylimidazole to represent the histidine side chain. Through a combination of in silico coordination chemistry as well as rigorous EXAFS curve-fitting, using full multiple scattering on candidate structures derived from DFT calculations, we have characterized the predominant coordination modes for the 1:1 complexes of Cu(II) , Cu(I) , and Zn(II) with the OR4 peptide at pH 7.4 at atomic resolution, which are best represented as square-planar [Cu(II) (His)4 ](2+) , digonal [Cu(I) (His)2 ](+) , and tetrahedral [Zn(II) (His)3 (OH2 )](2+) , respectively.
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Affiliation(s)
- M Jake Pushie
- Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK, S7N 5E2 (Canada), Fax: (+1) 306-966-8593.
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10
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - James Hall
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, United States
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11
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Sparacino-Watkins CE, Tejero J, Sun B, Gauthier MC, Thomas J, Ragireddy V, Merchant BA, Wang J, Azarov I, Basu P, Gladwin MT. Nitrite reductase and nitric-oxide synthase activity of the mitochondrial molybdopterin enzymes mARC1 and mARC2. J Biol Chem 2014; 289:10345-10358. [PMID: 24500710 DOI: 10.1074/jbc.m114.555177] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial amidoxime reducing component (mARC) proteins are molybdopterin-containing enzymes of unclear physiological function. Both human isoforms mARC-1 and mARC-2 are able to catalyze the reduction of nitrite when they are in the reduced form. Moreover, our results indicate that mARC can generate nitric oxide (NO) from nitrite when forming an electron transfer chain with NADH, cytochrome b5, and NADH-dependent cytochrome b5 reductase. The rate of NO formation increases almost 3-fold when pH was lowered from 7.5 to 6.5. To determine if nitrite reduction is catalyzed by molybdenum in the active site of mARC-1, we mutated the putative active site cysteine residue (Cys-273), known to coordinate molybdenum binding. NO formation was abolished by the C273A mutation in mARC-1. Supplementation of transformed Escherichia coli with tungsten facilitated the replacement of molybdenum in recombinant mARC-1 and abolished NO formation. Therefore, we conclude that human mARC-1 and mARC-2 are capable of catalyzing reduction of nitrite to NO through reaction with its molybdenum cofactor. Finally, expression of mARC-1 in HEK cells using a lentivirus vector was used to confirm cellular nitrite reduction to NO. A comparison of NO formation profiles between mARC and xanthine oxidase reveals similar Kcat and Vmax values but more sustained NO formation from mARC, possibly because it is not vulnerable to autoinhibition via molybdenum desulfuration. The reduction of nitrite by mARC in the mitochondria may represent a new signaling pathway for NADH-dependent hypoxic NO production.
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Affiliation(s)
- Courtney E Sparacino-Watkins
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Jesús Tejero
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Bin Sun
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Marc C Gauthier
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - John Thomas
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Venkata Ragireddy
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Bonnie A Merchant
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Jun Wang
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Ivan Azarov
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282
| | - Mark T Gladwin
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
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12
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Pushie MJ, Cotelesage JJ, George GN. Molybdenum and tungsten oxygen transferases – structural and functional diversity within a common active site motif. Metallomics 2014; 6:15-24. [DOI: 10.1039/c3mt00177f] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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13
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Reschke S, Sigfridsson KGV, Kaufmann P, Leidel N, Horn S, Gast K, Schulzke C, Haumann M, Leimkühler S. Identification of a bis-molybdopterin intermediate in molybdenum cofactor biosynthesis in Escherichia coli. J Biol Chem 2013; 288:29736-45. [PMID: 24003231 DOI: 10.1074/jbc.m113.497453] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molybdenum cofactor is an important cofactor, and its biosynthesis is essential for many organisms, including humans. Its basic form comprises a single molybdopterin (MPT) unit, which binds a molybdenum ion bearing three oxygen ligands via a dithiolene function, thus forming Mo-MPT. In bacteria, this form is modified to form the bis-MPT guanine dinucleotide cofactor with two MPT units coordinated at one molybdenum atom, which additionally contains GMPs bound to the terminal phosphate group of the MPTs (bis-MGD). The MobA protein catalyzes the nucleotide addition to MPT, but the mechanism of the biosynthesis of the bis-MGD cofactor has remained enigmatic. We have established an in vitro system for studying bis-MGD assembly using purified compounds. Quantification of the MPT/molybdenum and molybdenum/phosphorus ratios, time-dependent assays for MPT and MGD detection, and determination of the numbers and lengths of Mo-S and Mo-O bonds by X-ray absorption spectroscopy enabled identification of a novel bis-Mo-MPT intermediate on MobA prior to nucleotide attachment. The addition of Mg-GTP to MobA loaded with bis-Mo-MPT resulted in formation and release of the final bis-MGD product. This cofactor was fully functional and reconstituted the catalytic activity of apo-TMAO reductase (TorA). We propose a reaction sequence for bis-MGD formation, which involves 1) the formation of bis-Mo-MPT, 2) the addition of two GMP units to form bis-MGD on MobA, and 3) the release and transfer of the mature cofactor to the target protein TorA, in a reaction that is supported by the specific chaperone TorD, resulting in an active molybdoenzyme.
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Affiliation(s)
- Stefan Reschke
- From the Institute for Biochemistry and Biology, Department of Molecular Enzymology, and
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14
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Pushie MJ, Cotelesage JJH, Lyashenko G, Hille R, George GN. X-ray Absorption Spectroscopy of a Quantitatively Mo(V) Dimethyl Sulfoxide Reductase Species. Inorg Chem 2013; 52:2830-7. [DOI: 10.1021/ic301660e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- M. Jake Pushie
- Molecular and Environmental Sciences Research Group, Department of
Geological Sciences, University of Saskatchewan, SK, S7N 5E2, Canada
| | - Julien J. H. Cotelesage
- Molecular and Environmental Sciences Research Group, Department of
Geological Sciences, University of Saskatchewan, SK, S7N 5E2, Canada
- Canadian Light Source, 101 Perimeter Road,
Saskatoon, SK, S7N 0X4, Canada
| | - Ganna Lyashenko
- Department of Biochemistry, University of California-Riverside, Riverside, California 92521, United States
| | - Russ Hille
- Department of Biochemistry, University of California-Riverside, Riverside, California 92521, United States
| | - Graham N. George
- Molecular and Environmental Sciences Research Group, Department of
Geological Sciences, University of Saskatchewan, SK, S7N 5E2, Canada
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15
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George GN, Pickering IJ, Pushie MJ, Nienaber K, Hackett MJ, Ascone I, Hedman B, Hodgson KO, Aitken JB, Levina A, Glover C, Lay PA. X-ray-induced photo-chemistry and X-ray absorption spectroscopy of biological samples. JOURNAL OF SYNCHROTRON RADIATION 2012; 19:875-86. [PMID: 23093745 PMCID: PMC3480274 DOI: 10.1107/s090904951203943x] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 09/16/2012] [Indexed: 05/03/2023]
Abstract
As synchrotron light sources and optics deliver greater photon flux on samples, X-ray-induced photo-chemistry is increasingly encountered in X-ray absorption spectroscopy (XAS) experiments. The resulting problems are particularly pronounced for biological XAS experiments. This is because biological samples are very often quite dilute and therefore require signal averaging to achieve adequate signal-to-noise ratios, with correspondingly greater exposures to the X-ray beam. This paper reviews the origins of photo-reduction and photo-oxidation, the impact that they can have on active site structure, and the methods that can be used to provide relief from X-ray-induced photo-chemical artifacts.
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Affiliation(s)
- Graham N. George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Ingrid J. Pickering
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - M. Jake Pushie
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Kurt Nienaber
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Mark J. Hackett
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Isabella Ascone
- ENSCP Chimie ParisTech, LCF, CNRS, UMR 7223, 75005 Paris, France
| | - Britt Hedman
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Keith O. Hodgson
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jade B. Aitken
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
- Australian Synchrotron, Clayton, VIC 3168, Australia
- Institute of Materials Structure Science, KEK, Tsukuba, Ibaraki 305-0801, Japan
| | - Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Peter A. Lay
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
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16
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Cotelesage JJ, Pushie MJ, Grochulski P, Pickering IJ, George GN. Metalloprotein active site structure determination: Synergy between X-ray absorption spectroscopy and X-ray crystallography. J Inorg Biochem 2012; 115:127-37. [DOI: 10.1016/j.jinorgbio.2012.06.019] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/21/2012] [Accepted: 06/22/2012] [Indexed: 11/30/2022]
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17
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Qiu JA, Wilson HL, Rajagopalan KV. Structure-based alteration of substrate specificity and catalytic activity of sulfite oxidase from sulfite oxidation to nitrate reduction. Biochemistry 2012; 51:1134-47. [PMID: 22263579 DOI: 10.1021/bi201206v] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eukaryotic sulfite oxidase is a dimeric protein that contains the molybdenum cofactor and catalyzes the metabolically essential conversion of sulfite to sulfate as the terminal step in the metabolism of cysteine and methionine. Nitrate reductase is an evolutionarily related molybdoprotein in lower organisms that is essential for growth on nitrate. In this study, we describe human and chicken sulfite oxidase variants in which the active site has been modified to alter substrate specificity and activity from sulfite oxidation to nitrate reduction. On the basis of sequence alignments and the known crystal structure of chicken sulfite oxidase, two residues are conserved in nitrate reductases that align with residues in the active site of sulfite oxidase. On the basis of the crystal structure of yeast nitrate reductase, both positions were mutated in human sulfite oxidase and chicken sulfite oxidase. The resulting double-mutant variants demonstrated a marked decrease in sulfite oxidase activity but gained nitrate reductase activity. An additional methionine residue in the active site was proposed to be important in nitrate catalysis, and therefore, the triple variant was also produced. The nitrate reducing ability of the human sulfite oxidase triple mutant was nearly 3-fold greater than that of the double mutant. To obtain detailed structural data for the active site of these variants, we introduced the analogous mutations into chicken sulfite oxidase to perform crystallographic analysis. The crystal structures of the Mo domains of the double and triple mutants were determined to 2.4 and 2.1 Å resolution, respectively.
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Affiliation(s)
- James A Qiu
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
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Pushie MJ, Doonan CJ, Wilson HL, Rajagopalan KV, George GN. Nature of Halide Binding to the Molybdenum Site of Sulfite Oxidase. Inorg Chem 2011; 50:9406-13. [DOI: 10.1021/ic201030u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Jake Pushie
- Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Christian J. Doonan
- Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Heather L. Wilson
- School of Medicine, Duke University, Durham, North Carolina 27710, United States
| | - K. V. Rajagopalan
- School of Medicine, Duke University, Durham, North Carolina 27710, United States
| | - Graham. N. George
- Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
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The Chlamydomonas reinhardtii molybdenum cofactor enzyme crARC has a Zn-dependent activity and protein partners similar to those of its human homologue. EUKARYOTIC CELL 2011; 10:1270-82. [PMID: 21803866 DOI: 10.1128/ec.05096-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ARC (amidoxime reducing component) proteins are molybdenum cofactor (Moco) enzymes named hmARC1 and hmARC2 (human ARCs [hmARCs]) in humans and YcbX in Escherichia coli. They catalyze the reduction of a broad range of N-hydroxylated compounds (NHC) using reducing power supplied by other proteins. Some NHC are prodrugs or toxic compounds. YcbX contains a ferredoxin (Fd) domain and requires the NADPH flavin reductase CysJ to reduce NHC. In contrast, hmARCs lack the Fd domain and require a human cytochrome b5 (hCyt b5) and a human NADH Cyt b5 reductase (hCyt b5-R) to reduce NHC. The ARC proteins in the plant kingdom are uncharacterized. We demonstrate that Chlamydomonas reinhardtii mutants defective in Moco biosynthesis genes are sensitive to the NHC N(6)-hydroxylaminopurine (HAP). The Chlamydomonas reinhardtii ARC protein crARC has been purified and characterized. The six Chlamydomonas Fds were isolated, but none of them are required by crARC to reduce HAP. We have also purified and characterized five C. reinhardtii Cyt b5 (crCyt b5) and two flavin reductases, one that is NADPH dependent (crCysJ) and one that is NADH dependent (crCyt b5-R). The data show that crARC uses crCyt b5-1 and crCyt b5-R to reduce HAP. The crARC has a Zn-dependent activity, and the presence of Zn increases its V(max) more than 14-fold. In addition, all five cysteines of crARC were substituted by alanine, and we demonstrate that the fully conserved cysteine 252 is essential for both Moco binding and catalysis. Therefore, it is proposed that crARC belongs to the sulfite oxidase family of Moco enzymes.
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Abstract
Recent progress in our understanding of the structural and catalytic properties of molybdenum-containing enzymes in eukaryotes is reviewed, along with aspects of the biosynthesis of the cofactor and its insertion into apoprotein.
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Affiliation(s)
- Russ Hille
- Department of Biochemistry, University of California, Riverside, CA 92521
| | - Takeshi Nishino
- Department of Biochemistry and Molecular Biology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan and Department of Biochemistry, University of California, Riverside, CA 92521
| | - Florian Bittner
- Department of Plant Biology, Technical University of Braunschweig, 38023 Braunschweig, Germany
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Pushie MJ, Doonan CJ, Moquin K, Weiner JH, Rothery R, George GN. Molybdenum Site Structure of Escherichia coli YedY, a Novel Bacterial Oxidoreductase. Inorg Chem 2010; 50:732-40. [DOI: 10.1021/ic101280m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Jake Pushie
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Christian J. Doonan
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Kamila Moquin
- School of Molecular and Systems Medicine, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Joel H. Weiner
- School of Molecular and Systems Medicine, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Richard Rothery
- School of Molecular and Systems Medicine, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Graham N. George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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Pérez E, Cardemil E. Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase: the relevance of Glu299 and Leu460 for nucleotide binding. Protein J 2010; 29:299-305. [PMID: 20524049 DOI: 10.1007/s10930-010-9252-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A homology model of Saccharomyces cerevisiae phosphoenolpyruvate (PEP) carboxykinase (ATP + oxaloacetate right arrow over left arrow ADP + PEP + CO(2)) in complex with its substrates shows that the isobutyl group of Leu460 is in close proximity to the adenine ring of the nucleotide, while the carboxyl group of Glu299 is within hydrogen-bonding distance of the ribose 2'OH. The Leu460Ala mutation caused three-fold and seven-fold increases in the K (m) for ADPMn(-) and ATPMn(2-), respectively, while the Glu299Ala mutation had no effect. Binding studies showed losses of approximately 2 kcal mol(-1) in the nucleotide binding affinity due to the Leu460Ala mutation and no effect for the Glu299Ala mutation. PEP carboxykinase utilized 2'deoxyADP and 2'deoxyATP as substrates with kinetic and equilibrium dissociation constants very similar to those of ADP and ATP, respectively. These results show that the hydrophobic interaction between Leu460 and the adenine ring of the nucleotide significantly contributed to the nucleotide affinity of the enzyme. The 2'deoxy nucleotide studies and the lack of an effect of the Glu299Ala mutation in nucleotide binding suggest that the possible hydrogen bond contributed by Glu299 and the ribose 2'OH group may not be relevant for nucleotide binding.
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Affiliation(s)
- Estela Pérez
- Facultad de Química y Biología, Universidad de Santiago de Chile, Av. B. O'Higgins 3363, Santiago, Chile
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