1
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Kirk ML, Lepluart J, Yang J. Resonance Raman spectroscopy of pyranopterin molybdenum enzymes. J Inorg Biochem 2022; 235:111907. [PMID: 35932756 PMCID: PMC10575615 DOI: 10.1016/j.jinorgbio.2022.111907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 05/16/2022] [Accepted: 06/16/2022] [Indexed: 10/17/2022]
Abstract
Resonance Raman spectroscopy (rR) is a powerful spectroscopic probe that is widely used for studying the geometric and electronic structure of metalloproteins. In this focused review, we detail how resonance Raman spectroscopy has contributed to a greater understanding of electronic structure, geometric structure, and the reaction mechanisms of pyranopterin molybdenum enzymes. The review focuses on the enzymes sulfite oxidase (SO), dimethyl sulfoxide reductase (DMSOR), xanthine oxidase (XO), and carbon monoxide dehydrogenase. Specifically, we highlight how Mo-Ooxo, Mo-Ssulfido, Mo-Sdithiolene, and dithiolene CC vibrational modes, isotope and heavy atom perturbations, resonance enhancement, and associated Raman studies of small molecule analogs have provided detailed insight into the nature of these metalloenzyme active sites.
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Affiliation(s)
- Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States.
| | - Jesse Lepluart
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
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2
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Kirk ML, Hille R. Spectroscopic Studies of Mononuclear Molybdenum Enzyme Centers. Molecules 2022; 27:4802. [PMID: 35956757 PMCID: PMC9370002 DOI: 10.3390/molecules27154802] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 02/06/2023] Open
Abstract
A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of mononuclear molybdenum enzymes. Contributions to our understanding of the structure and function of each of the major families of these enzymes is considered, providing a perspective on how spectroscopy has impacted the field.
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Affiliation(s)
- Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA
| | - Russ Hille
- Department of Biochemistry, Boyce Hall 1463, University of California, Riverside, CA 82521, USA
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3
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Vogt LI, Dolgova NV, Cotelesage JJH, Barney M, Sharifi S, Pickering IJ, George GN. Sulfur K-Edge X-ray Absorption Spectroscopy of Aryl and Aryl–Alkyl Sulfides. J Phys Chem A 2019; 123:2861-2866. [DOI: 10.1021/acs.jpca.9b00908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Linda I. Vogt
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Natalia V. Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Julien J. H. Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Monica Barney
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Samin Sharifi
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Ingrid J. Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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4
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Block E, Dethier B, Bechand B, Cotelesage JJH, George GN, Goto K, Pickering IJ, Mendoza Rengifo E, Sheridan R, Sneeden EY, Vogt L. Ajothiolanes: 3,4-Dimethylthiolane Natural Products from Garlic ( Allium sativum). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:10193-10204. [PMID: 30196701 DOI: 10.1021/acs.jafc.8b03638] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stereoisomers of 5-(2-allylsulfinyl)-3,4-dimethylthiolane-2-ol, a family of 3,4-dimethylthiolanes of formula C9H16O2S2 we name ajothiolanes, were isolated from garlic ( Allium sativum) macerates and characterized by a variety of analytical and spectroscopic techniques, including ultraperformance liquid chromatography (UPLC), direct analysis in real time-mass spectrometry (DART-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Ajothiolanes were found to be spectroscopically identical to a family of previously described compounds named garlicnins B1-4 (C9H16O2S2), whose structures we demonstrate have been misassigned. 2D 13C-13C NMR incredible natural abundance double quantum transfer experiments (INADEQUATE) were used to disprove the claim of nine contiguous carbons in these compounds, while X-ray absorption spectroscopy (XAS) along with computational modeling was used to disprove the claim that these compounds were thiolanesulfenic acids. On the basis of the similarity of their NMR spectra to those of the ajothiolanes, we propose that the structures of previously described, biologically active onionins A1-3 (C9H16O2S2), from extracts of onion ( Allium cepa) and Allium fistulosum, and garlicnin A (C12H20O2S4), from garlic extracts, should also be reassigned, in each case as isomeric mixtures of 5-substituted-3,4-dimethylthiolane-2-ols. We conclude that 3,4-dimethylthiolanes may be a common motif in Allium chemistry. Finally, we show that another garlic extract component, garlicnin D (C7H12O2S3), claimed to have an unprecedented structure, is in fact a known compound from garlic with a structure different from that proposed, namely, 2( E)-3-(methylsulfinyl)-2-propenyl 2-propenyl disulfide.
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Affiliation(s)
- Eric Block
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
| | - Bérénice Dethier
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
| | - Benjamin Bechand
- Department of Chemistry , University at Albany, State University of New York , Albany , New York 12222 , United States
| | - Julien J H Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Kei Goto
- Department of Chemistry , Tokyo Institute of Technology , 2-12-1 O̅okayama , Meguro̅ku, Tokyo 152-8551 , Japan
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Emerita Mendoza Rengifo
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Robert Sheridan
- Food Laboratory Division , NYS Department of Agriculture and Markets , Albany , New York 12235 , United States
| | - Eileen Y Sneeden
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Linda Vogt
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
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5
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Gisewhite DR, Yang J, Williams BR, Esmail A, Stein B, Kirk ML, Burgmayer SJN. Implications of Pyran Cyclization and Pterin Conformation on Oxidized Forms of the Molybdenum Cofactor. J Am Chem Soc 2018; 140:12808-12818. [PMID: 30200760 DOI: 10.1021/jacs.8b05777] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The large family of mononuclear molybdenum and tungsten enzymes all possess the special ligand molybdopterin (MPT), which consists of a metal-binding dithiolene chelate covalently bound to a pyranopterin group. MPT pyran cyclization/scission processes have been proposed to modulate the reactivity of the metal center during catalysis. We have designed several small-molecule models for the Mo-MPT cofactor that allow detailed investigation into how pyran cyclization modulates electronic communication between the dithiolene and pterin moieties and how this cyclization alters the electronic environment of the molybdenum catalytic site. Using a combination of cyclic voltammetry, vibrational spectroscopy (FT-IR and rR), electronic absorption spectroscopy, and X-ray absorption spectroscopy, distinct changes in the Mo≡O stretching frequency, Mo(V/IV) reduction potential, and electronic structure across the pterin-dithiolene ligand are observed as a function of pyran ring closure. The results are significant, for they reveal that a dihydropyranopterin is electronically coupled into the Mo-dithiolene group due to a coplanar conformation of the pterin and dithiolene units, providing a mechanism for the electron-deficient pterin to modulate the Mo environment. A spectroscopic signature identified for the dihydropyranopterin-dithiolene ligand on Mo is a strong dithiolene → pterin charge transfer transition. In the absence of a pyran group bridge between pterin and dithiolene, the pterin rotates out of plane, largely decoupling the system. The results support a hypothesis that pyran cyclization/scission processes in MPT may function as a molecular switch to electronically couple and decouple the pterin and dithiolene to adjust the redox properties in certain pyranopterin molybdenum enzymes.
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Affiliation(s)
- Douglas R Gisewhite
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Jing Yang
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Benjamin R Williams
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Alisha Esmail
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
| | - Benjamin Stein
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology , The University of New Mexico , MSC03 2060, 1 University of New Mexico , Albuquerque , New Mexico 87131-0001 , United States
| | - Sharon J N Burgmayer
- Department of Chemistry , Bryn Mawr College , Bryn Mawr , Pennsylvania 19010 , United States
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6
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Nehzati S, Dolgova NV, Sokaras D, Kroll T, Cotelesage JJH, Pickering IJ, George GN. A Photochemically Generated Selenyl Free Radical Observed by High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy. Inorg Chem 2018; 57:10867-10872. [PMID: 30133265 DOI: 10.1021/acs.inorgchem.8b01522] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Selenium-based selenyl free radicals are chemical entities that may be involved in a range of biochemical processes. We report the first X-ray spectroscopic observation of a selenyl radical species generated photochemically by X-ray irradiation of low-temperature solutions of l-selenocysteine. We have employed high energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) and electron paramagnetic resonance (EPR) spectroscopy, coupled with density functional theory calculations, to characterize and understand the species. The HERFD-XAS spectrum of the selenyl radical is distinguished by a uniquely low-energy transition with a peak energy at 12 659.0 eV, which corresponds to a 1s → 4p transition to the singly occupied molecular orbital of the free radical. The EPR spectrum shows the broad features and highly anisotropic g-values that are expected for a selenium free radical species. The availability of spectroscopic probes for selenyl radicals may assist in understanding why life chooses selenium over sulfur in selected biochemical processes.
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Affiliation(s)
- Susan Nehzati
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory, Stanford University , Menlo Park , California 94025 , United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory, Stanford University , Menlo Park , California 94025 , United States
| | - Julien J H Cotelesage
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5C9 , Canada
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7
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Sneeden EY, Hackett MJ, Cotelesage JJH, Prince RC, Barney M, Goto K, Block E, Pickering IJ, George GN. Photochemically Generated Thiyl Free Radicals Observed by X-ray Absorption Spectroscopy. J Am Chem Soc 2017; 139:11519-11526. [DOI: 10.1021/jacs.7b05116] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Eileen Y. Sneeden
- Stanford
Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Mark J. Hackett
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, Curtin University, Bentley, Western Australia 6845, Australia
| | - Julien J. H. Cotelesage
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Roger C. Prince
- Stonybrook Apiary, Pittstown, New Jersey 08867, United States
| | - Monica Barney
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Kei Goto
- Tokyo Institute of Technology, Department of Chemistry, 2-12-1 O̅okayama, Meguro̅ku, Tokyo 152-8551, Japan
| | - Eric Block
- Department
of Chemistry, University at Albany, State University of New York, Albany, New York 12222, United States
| | - Ingrid J. Pickering
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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8
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Cotelesage JJH, Barney M, Vogt L, Pickering IJ, George GN. X-ray Absorption Spectroscopy of Aliphatic Organic Sulfides. J Phys Chem A 2017; 121:6256-6261. [DOI: 10.1021/acs.jpca.7b04395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Julien J. H. Cotelesage
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Monica Barney
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Linda Vogt
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Ingrid J. Pickering
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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9
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Robinson WE, Bassegoda A, Reisner E, Hirst J. Oxidation-State-Dependent Binding Properties of the Active Site in a Mo-Containing Formate Dehydrogenase. J Am Chem Soc 2017; 139:9927-9936. [PMID: 28635274 PMCID: PMC5532686 DOI: 10.1021/jacs.7b03958] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Molybdenum-containing formate dehydrogenase H from Escherichia coli (EcFDH-H) is a powerful model system for studies of the reversible reduction of CO2 to formate. However, the mechanism of FDH catalysis is currently under debate, and whether the primary Mo coordination sphere remains saturated or one of the ligands dissociates to allow direct substrate binding during turnover is disputed. Herein, we describe how oxidation-state-dependent changes at the active site alter its inhibitor binding properties. Using protein film electrochemistry, we show that formate oxidation by EcFDH-H is inhibited strongly and competitively by N3-, OCN-, SCN-, NO2-, and NO3-, whereas CO2 reduction is inhibited only weakly and not competitively. During catalysis, the Mo center cycles between the formal Mo(VI)═S and Mo(IV)-SH states, and by modeling chronoamperometry data recorded at different potentials and substrate and inhibitor concentrations, we demonstrate that both formate oxidation and CO2 reduction are inhibited by selective inhibitor binding to the Mo(VI)═S state. The strong dependence of inhibitor-binding affinity on both Mo oxidation state and inhibitor electron-donor strength indicates that inhibitors (and substrates) bind directly to the Mo center. We propose that inhibitors bind to the Mo following dissociation of a selenocysteine ligand to create a vacant coordination site for catalysis and close by considering the implications of our data for the mechanisms of formate oxidation and CO2 reduction.
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Affiliation(s)
- William E Robinson
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Arnau Bassegoda
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
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10
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Sproules S, Eagle AA, George GN, White JM, Young CG. Mononuclear Sulfido-Tungsten(V) Complexes: Completing the Tp*MEXY (M = Mo, W; E = O, S) Series. Inorg Chem 2017; 56:5189-5202. [DOI: 10.1021/acs.inorgchem.7b00331] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Aston A. Eagle
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Graham N. George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Jonathan M. White
- School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Charles G. Young
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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11
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Pickering IJ, Barney M, Cotelesage JJH, Vogt L, Pushie MJ, Nissan A, Prince RC, George GN. Chemical Sensitivity of the Sulfur K-Edge X-ray Absorption Spectra of Organic Disulfides. J Phys Chem A 2016; 120:7279-86. [DOI: 10.1021/acs.jpca.6b06790] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ingrid J. Pickering
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Monica Barney
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Julien J. H. Cotelesage
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Linda Vogt
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - M. Jake Pushie
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Andrew Nissan
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Roger C. Prince
- ExxonMobil Biomedical Sciences, Inc., Annandale, New Jersey 08801, United States
| | - Graham N. George
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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12
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Young CG. Chemical systems modeling the d1 Mo(V) states of molybdenum enzymes. J Inorg Biochem 2016; 162:238-252. [PMID: 27432259 DOI: 10.1016/j.jinorgbio.2016.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/14/2016] [Accepted: 06/03/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Charles G Young
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
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13
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Cotelesage JJH, Pushie MJ, Vogt L, Barney M, Nissan A, Pickering IJ, George GN. Insights into the Nature of the Chemical Bonding in Thiophene-2-thiol from X-ray Absorption Spectroscopy. J Phys Chem A 2016; 120:6929-33. [DOI: 10.1021/acs.jpca.6b05874] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julien J. H. Cotelesage
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - M. Jake Pushie
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Linda Vogt
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Monica Barney
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Andrew Nissan
- Chevron Energy Technology Company, Richmond, California 94802, United States
| | - Ingrid J. Pickering
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada
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14
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Affiliation(s)
- Charles G. Young
- Department of Chemistry and PhysicsLa Trobe Institute for Molecular ScienceLa Trobe University3086MelbourneVictoriaAustralia
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15
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Olson AC, Keith JM, Batista ER, Boland KS, Daly SR, Kozimor SA, MacInnes MM, Martin RL, Scott BL. Using solution- and solid-state S K-edge X-ray absorption spectroscopy with density functional theory to evaluate M-S bonding for MS4(2-) (M = Cr, Mo, W) dianions. Dalton Trans 2015; 43:17283-95. [PMID: 25311904 DOI: 10.1039/c4dt02302a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we have evaluated relative changes in M-S electronic structure and orbital mixing in Group 6 MS4(2-) dianions using solid- and solution-phase S K-edge X-ray absorption spectroscopy (XAS; M = Mo, W), as well as density functional theory (DFT; M = Cr, Mo, W) and time-dependent density functional theory (TDDFT) calculations. To facilitate comparison with solution measurements (conducted in acetonitrile), theoretical models included gas-phase calculations as well as those that incorporated an acetonitrile dielectric, the latter of which provided better agreement with experiment. Two pre-edge features arising from S 1s → e* and t electron excitations were observed in the S K-edge XAS spectra and were reasonably assigned as (1)A1 → (1)T2 transitions. For MoS4(2-), both solution-phase pre-edge peak intensities were consistent with results from the solid-state spectra. For WS4(2-), solution- and solid-state pre-edge peak intensities for transitions involving e* were equivalent, while transitions involving the t orbitals were less intense in solution. Experimental and computational results have been presented in comparison to recent analyses of MO4(2-) dianions, which allowed M-S and M-O orbital mixing to be evaluated as the principle quantum number (n) for the metal valence d orbitals increased (3d, 4d, 5d). Overall, the M-E (E = O, S) analyses revealed distinct trends in orbital mixing. For example, as the Group 6 triad was descended, e* (π*) orbital mixing remained constant in the M-S bonds, but increased appreciably for M-O interactions. For the t orbitals (σ* + π*), mixing decreased slightly for M-S bonding and increased only slightly for the M-O interactions. These results suggested that the metal and ligand valence orbital energies and radial extensions delicately influenced the orbital compositions for isoelectronic ME4(2-) (E = O, S) dianions.
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Affiliation(s)
- Angela C Olson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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16
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Doonan CJ, Gourlay C, Nielsen DJ, Ng VWL, Smith PD, Evans DJ, George GN, White JM, Young CG. d(1) Oxosulfido-Mo(V) Compounds: First Isolation and Unambiguous Characterization of an Extended Series. Inorg Chem 2015; 54:6386-96. [PMID: 26046577 DOI: 10.1021/acs.inorgchem.5b00708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction of Tp(iPr)Mo(VI)OS(OAr) with cobaltocene in toluene results in the precipitation of brown, microcrystalline oxosulfido-Mo(V) compounds, [CoCp2][Tp(iPr)Mo(V)OS(OAr)] (Cp(-) = η(5)-C5H5(-), Tp(iPr)(-) = hydrotris(3-isopropylpyrazol-1-yl)borate, OAr(-) = phenolate or 2-(s)Bu, 2-(t)Bu, 3-(t)Bu, 4-(s)Bu, 4-Ph, 3,5-(s)Bu2, 2-CO2Me, 2-CO2Et or 2-CO2Ph derivative thereof). The compounds are air- and water-sensitive and display ν(Mo═O) and ν(Mo[Formula: see text]S) IR absorption bands at ca. 890 and 435 cm(-1), respectively, 20-40 cm(-1) lower in energy than the corresponding bands in Tp(iPr)MoOS(OAr). They are electrochemically active and exhibit three reversible cyclovoltammetric waves (E(Mo(VI)/Mo(V)) = -0.40 to -0.66 V, E([CoCp2](+)/CoCp2) = -0.94 V and E(CoCp2/[CoCp2](-)) = -1.88 V vs SCE). Structural characterization of [CoCp2][Tp(iPr)MoOS(OC6H4CO2Et-2)]·2CH2Cl2 revealed a distorted octahedral Mo(V) anion with Mo═O and Mo[Formula: see text]S distances of 1.761(5) and 2.215(2) Å, respectively, longer than corresponding distances in related Tp(iPr)MoOS(OAr) compounds. The observation of strong S(1s) → (S(3p) + Mo(4d)) S K-preedge transitions indicative of a d(1) sulfido-Mo(V) moiety and the presence of short Mo═O (ca. 1.72 Å) and Mo[Formula: see text]S (ca. 2.25 Å) backscattering contributions in the Mo K-edge EXAFS further support the oxosulfido-Mo(V) formulation. The compounds are EPR-active, exhibiting highly anisotropic (Δg 0.124-0.150), rhombic, frozen-glass spectra with g1 close to the value observed for the free electron (ge = 2.0023). Spectroscopic studies are consistent with the presence of a highly covalent Mo[Formula: see text]S π* singly occupied molecular orbital. The compounds are highly reactive, with reactions localized at the terminal sulfido ligand. For example, the compounds react with cyanide and PPh3 to produce thiocyanate and SPPh3, respectively, and various (depending on solvent) oxo-Mo(V) species. Reactions with copper reagents also generally lead to desulfurization and the formation of oxo-Mo(V) or -Mo(IV) complexes.
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Affiliation(s)
| | | | | | | | | | | | - Graham N George
- §Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | | | - Charles G Young
- ¶Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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Stein BW, Kirk ML. Electronic structure contributions to reactivity in xanthine oxidase family enzymes. J Biol Inorg Chem 2015; 20:183-94. [PMID: 25425163 PMCID: PMC4867223 DOI: 10.1007/s00775-014-1212-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/30/2014] [Indexed: 11/25/2022]
Abstract
We review the xanthine oxidase (XO) family of pyranopterin molybdenum enzymes with a specific emphasis on electronic structure contributions to reactivity. In addition to xanthine and aldehyde oxidoreductases, which catalyze the two-electron oxidation of aromatic heterocycles and aldehyde substrates, this mini-review highlights recent work on the closely related carbon monoxide dehydrogenase (CODH) that catalyzes the oxidation of CO using a unique Mo-Cu heterobimetallic active site. A primary focus of this mini-review relates to how spectroscopy and computational methods have been used to develop an understanding of critical relationships between geometric structure, electronic structure, and catalytic function.
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Affiliation(s)
- Benjamin W. Stein
- Department of Chemistry and Chemical Biology, University of New Mexico, MSC03 2060, 300 Terrace St. NE, Albuquerque, NM 87131
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, University of New Mexico, MSC03 2060, 300 Terrace St. NE, Albuquerque, NM 87131
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18
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Nitrite reduction by molybdoenzymes: a new class of nitric oxide-forming nitrite reductases. J Biol Inorg Chem 2015; 20:403-33. [DOI: 10.1007/s00775-014-1234-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/14/2014] [Indexed: 02/07/2023]
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19
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Maia LB, Pereira V, Mira L, Moura JJG. Nitrite reductase activity of rat and human xanthine oxidase, xanthine dehydrogenase, and aldehyde oxidase: evaluation of their contribution to NO formation in vivo. Biochemistry 2015; 54:685-710. [PMID: 25537183 DOI: 10.1021/bi500987w] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitrite is presently considered a NO "storage form" that can be made available, through its one-electron reduction, to maintain NO formation under hypoxia/anoxia. The molybdoenzymes xanthine oxidase/dehydrogenase (XO/XD) and aldehyde oxidase (AO) are two of the most promising mammalian nitrite reductases, and in this work, we characterized NO formation by rat and human XO/XD and AO. This is the first characterization of human enzymes, and our results support the employment of rat liver enzymes as suitable models of the human counterparts. A comprehensive kinetic characterization of the effect of pH on XO and AO-catalyzed nitrite reduction showed that the enzyme's specificity constant for nitrite increase 8-fold, while the Km(NO2(-)) decrease 6-fold, when the pH decreases from 7.4 to 6.3. These results demonstrate that the ability of XO/AO to trigger NO formation would be greatly enhanced under the acidic conditions characteristic of ischemia. The dioxygen inhibition was quantified, and the Ki(O2) values found (24.3-48.8 μM) suggest that in vivo NO formation would be fine-tuned by dioxygen availability. The potential in vivo relative physiological relevance of XO/XD/AO-dependent pathways of NO formation was evaluated using HepG2 and HMEC cell lines subjected to hypoxia. NO formation by the cells was found to be pH-, nitrite-, and dioxygen-dependent, and the relative contribution of XO/XD plus AO was found to be as high as 50%. Collectively, our results supported the possibility that XO/XD and AO can contribute to NO generation under hypoxia inside a living human cell. Furthermore, the molecular mechanism of XO/AO-catalyzed nitrite reduction was revised.
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Affiliation(s)
- Luisa B Maia
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal
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20
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George GN, Hackett MJ, Sansone M, Gorbaty ML, Kelemen SR, Prince RC, Harris HH, Pickering IJ. Long-range chemical sensitivity in the sulfur K-edge X-ray absorption spectra of substituted thiophenes. J Phys Chem A 2014; 118:7796-802. [PMID: 25116792 PMCID: PMC4161161 DOI: 10.1021/jp505766f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Thiophenes are the simplest aromatic
sulfur-containing compounds
and are stable and widespread in fossil fuels. Regulation of sulfur
levels in fuels and emissions has become and continues to be ever
more stringent as part of governments’ efforts to address negative
environmental impacts of sulfur dioxide. In turn, more effective removal
methods are continually being sought. In a chemical sense, thiophenes
are somewhat obdurate and hence their removal from fossil fuels poses
problems for the industrial chemist. Sulfur K-edge X-ray absorption
spectroscopy provides key information on thiophenic components in
fuels. Here we present a systematic study of the spectroscopic sensitivity
to chemical modifications of the thiophene system. We conclude that
while the utility of sulfur K-edge X-ray absorption spectra in understanding
the chemical composition of sulfur-containing fossil fuels has already
been demonstrated, care must be exercised in interpreting these spectra
because the assumption of an invariant spectrum for thiophenic forms
may not always be valid.
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Affiliation(s)
- Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5E2, Canada
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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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22
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Affiliation(s)
- Luisa B. Maia
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - 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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23
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Ng VWL, White JM, Young CG. Structural Characterization and Unusual Reactivity of Oxosulfido-Mo(V) Compounds: Implications for the Structure and Electronic Description of the Very Rapid Form of Xanthine Oxidase. J Am Chem Soc 2013; 135:7106-9. [DOI: 10.1021/ja4022057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Victor W. L. Ng
- School
of Chemistry and ‡Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010,
Australia
| | - Jonathan M. White
- School
of Chemistry and ‡Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010,
Australia
| | - Charles G. Young
- School
of Chemistry and ‡Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010,
Australia
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24
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Abstract
We have performed a computational study of substrate C-H bond activation in enzymes of the XO family. The C-H H-atom for all XO substrates studied is transferred to the terminal sulfido at the transition state with near neutral charge, and this is consistent with both Mo=S π→ C-H σ* and C-H σ→Mo=S π* donor-acceptor interactions activating the C-H bond. A C-H bond scission and Mo reduction appear to be highly correlated along the reaction coordinate for all XO substrates studied, with Mo reduction being a continuous and exponential function of C-H bond breaking along the reaction coordinate.
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Affiliation(s)
- Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC02 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA.
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Sempombe J, Stein B, Kirk ML. Spectroscopic and electronic structure studies probing covalency contributions to C-H bond activation and transition-state stabilization in xanthine oxidase. Inorg Chem 2011; 50:10919-28. [PMID: 21972782 DOI: 10.1021/ic201477n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A detailed electron paramagnetic resonance (EPR) and computational study of a key paramagnetic form of xanthine oxidase (XO) has been performed and serves as a basis for developing a valence-bond description of C-H activation and transition-state (TS) stabilization along the reaction coordinate with aldehyde substrates. EPR spectra of aldehyde-inhibited XO have been analyzed in order to provide information regarding the relationship between the g, (95,97)Mo hyperfine (A(Mo)), and (13)C hyperfine (A(C)) tensors. Analysis of the EPR spectra has allowed for greater insight into the electronic origin of key delocalizations within the Mo-O(eq)-C fragment and how these contribute to C-H bond activation/cleavage and TS stabilization. A natural bond orbital analysis of the enzyme reaction coordinate with aldehyde substrates shows that both Mo═S π → C-H σ* (ΔE = 24.3 kcal mol(-1)) and C-H σ → Mo═S π* (ΔE = 20.0 kcal mol(-1)) back-donation are important in activating the substrate C-H bond for cleavage. Additional contributions to C-H activation derive from O(eq) lp → C-H σ* (lp = lone pair; ΔE = 8.2 kcal mol(-1)) and S lp → C-H σ* (ΔE = 13.2 kcal mol(-1)) stabilizing interactions. The O(eq)-donor ligand that derives from water is part of the Mo-O(eq)-C fragment probed in the EPR spectra of inhibited XO, and the observation of O(eq) lp → C-H σ* back-donation indicates a key role for O(eq) in activating the substrate C-H bond for cleavage. We also show that the O(eq) donor plays an even more important role in TS stabilization. We find that O(eq) → Mo + C charge transfer dominantly contributes to stabilization of the TS (ΔE = 89.5 kcal mol(-1)) and the Mo-O(eq)-C delocalization pathway reduces strong electronic repulsions that contribute to the classical TS energy barrier. The Mo-O(eq)-C delocalization at the TS allows for the TS to be described in valence-bond terms as a resonance hybrid of the reactant (R) and product (P) valence-bond wave functions.
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Affiliation(s)
- Joseph Sempombe
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
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26
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Samuel PP, Horn S, Döring A, Havelius KGV, Reschke S, Leimkühler S, Haumann M, Schulzke C. A Crystallographic and Mo K-Edge XAS Study of Molybdenum Oxo Bis-, Mono-, and Non-Dithiolene Complexes - First-Sphere Coordination Geometry and Noninnocence of Ligands. Eur J Inorg Chem 2011. [DOI: 10.1002/ejic.201100331] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Lu TT, Lai SH, Li YW, Hsu IJ, Jang LY, Lee JF, Chen IC, Liaw WF. Discrimination of Mononuclear and Dinuclear Dinitrosyl Iron Complexes (DNICs) by S K-Edge X-ray Absorption Spectroscopy: Insight into the Electronic Structure and Reactivity of DNICs. Inorg Chem 2011; 50:5396-406. [DOI: 10.1021/ic102108b] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tsai-Te Lu
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Szu-Hsueh Lai
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ya-Wen Li
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
| | - I-Jui Hsu
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
| | - Ling-Yun Jang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Jyh-Fu Lee
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - I-Chia Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
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29
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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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30
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Sugimoto H, Tano H, Suyama K, Kobayashi T, Miyake H, Itoh S, Mtei RP, Kirk ML. Chalcogenidobis(ene-1,2-dithiolate)molybdenum(IV) complexes (chalcogenide E = O, S, Se): probing Mo≡E and ene-1,2-dithiolate substituent effects on geometric and electronic structure. Dalton Trans 2011; 40:1119-31. [PMID: 21165484 PMCID: PMC3168557 DOI: 10.1039/c0dt00871k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New square-pyramidal bis(ene-1,2-dithiolate)MoSe complexes, [Mo(IV)Se(L)(2)](2-), have been synthesised along with their terminal sulfido analogues, [Mo(IV)S(L)(2)](2-), using alkyl (L(C(4)H(8))), phenyl (L(Ph)) and methyl carboxylate (L(COOMe)) substituted dithiolene ligands (L). These complexes now complete three sets of Mo(IV)O, Mo(IV)S and Mo(IV)Se species that are coordinated with identical ene-1,2-dithiolate ligands. The [alkyl substituted Mo(S/Se)(L(C(4)H(8)))(2)](2-) complexes were reported in prior investigations (H. Sugimoto, T. Sakurai, H. Miyake, K. Tanaka and H. Tsukube, Inorg. Chem. 2005, 44, 6927, H. Tano, R. Tajima, H. Miyake, S. Itoh and H. Sugimoto, Inorg. Chem. 2008, 47, 7465). The new series of complexes enable a systematic investigation of terminal chalcogenido and supporting ene-1,2-dithiolate ligand effects on geometric structure, electronic structure, and spectroscopic properties. X-ray crystallographic analysis of these (Et(4)N)(2)[MoEL(2)] (E = terminal chalocogenide) complexes reveals an isostructural Mo centre that adopts a distorted square pyramidal geometry. The M≡E bond distances observed in the crystal structures and the ν(M≡E) vibrational frequencies indicate that these bonds are weakened with an increase in L→Mo electron donation (L(COOMe) < L(Ph) < L(C(4)H(8))), and this order is confirmed by an electrochemical study of the complexes. The (77)Se NMR resonances in MoSeL complexes appear at lower magnetic fields as the selenido ion became less basic from MoSeL(C(4)H(8)), MoSeL(Ph) and MoSeL(COOMe). Electronic absorption and resonance Raman spectroscopies have been used to assign key ligand-field, MLCT, LMCT and intraligand CT bands in complexes that possess the L(COOMe) ligand. The presence of low-energy intraligand CT transition in these MoEL(COOMe) compounds directly probes the electron withdrawing nature of the -COOMe substituents, and this underscores the complex electronic structure of square pyramidal bis(ene-1,2-dithiolate)-Mo(IV) complexes that possess extended dithiolene conjugation.
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Affiliation(s)
- Hideki Sugimoto
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871Japan
| | - Hiroyuki Tano
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Koichiro Suyama
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tomoya Kobayashi
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hiroyuki Miyake
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shinobu Itoh
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871Japan
| | - Regina P. Mtei
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131–0001, USA
| | - Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131–0001, USA
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31
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Alfaro JF, Jones JP. Studies on the mechanism of aldehyde oxidase and xanthine oxidase. J Org Chem 2010; 73:9469-72. [PMID: 18998731 DOI: 10.1021/jo801053u] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DFT calculations support a concerted mechanism for xanthine oxidase and aldehyde oxidase hydride displacement from the sp(2) carbon of 6-substituted 4-quinazolinones. The variations in transition state structure show that C-O bond formation is nearly complete in the transition state and the transition state changes are anti-Hammond with the C-H and C-O bond lengths being more product-like for the faster reactions. The C-O bond length in the transition state is around 90% formed. However, the C-H bond is only about 80% broken. This leads to a very tetrahedral transition state with an O-C-N angle of 109 degrees. Thus, while the mechanism is concerted, the antibonding orbital of the C-H bond that is broken is not directly attacked by the nucleophile and instead hydride displacement occurs after almost complete tetrahedral transition state formation. In support of this the C=N bond is lengthened in the transition state indicating that attack on the electrophilic carbon occurs by addition to the C=N bond with negative charge increasing on the nitrogen. Differences in experimental reaction rates are accurately reproduced by these calculations and tend to support this mechanism.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
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32
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Bradley JA, Yang P, Batista ER, Boland KS, Burns CJ, Clark DL, Conradson SD, Kozimor SA, Martin RL, Seidler GT, Scott BL, Shuh DK, Tyliszczak T, Wilkerson MP, Wolfsberg LE. Experimental and Theoretical Comparison of the O K-Edge Nonresonant Inelastic X-ray Scattering and X-ray Absorption Spectra of NaReO4. J Am Chem Soc 2010; 132:13914-21. [DOI: 10.1021/ja1040978] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Joseph A. Bradley
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Ping Yang
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Enrique R. Batista
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Kevin S. Boland
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Carol J. Burns
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - David L. Clark
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Steven D. Conradson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Stosh A. Kozimor
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Richard L. Martin
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Gerald T. Seidler
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Brian L. Scott
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - David K. Shuh
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Tolek Tyliszczak
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Marianne P. Wilkerson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Laura E. Wolfsberg
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Physics, University of Washington, Seattle, Washington 98195, Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and W.R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
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Active transition metal oxo and hydroxo moieties in nature's redox, enzymes and their synthetic models: Structure and reactivity relationships. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2010.01.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Gourlay C, Taylor MK, Smith PD, Young CG. Isovalent and mixed-valent molybdenum complexes containing MoV(μ-E)(μ-S2)MoV/IV (E = O, S) core units. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2009.09.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yang J, Rothery R, Sempombe J, Weiner JH, Kirk ML. Spectroscopic characterization of YedY: the role of sulfur coordination in a Mo(V) sulfite oxidase family enzyme form. J Am Chem Soc 2010; 131:15612-4. [PMID: 19860477 DOI: 10.1021/ja903087k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic paramagnetic resonance (EPR), electronic absorption, and magnetic circular dichroism spectroscopies have been performed on YedY, a SUOX fold protein with a Mo domain that is remarkably similar to that found in chicken sulfite oxidase, Arabidopsis thaliana plant sulfite oxidase, and the bacterial sulfite dehydrogenase from Starkeya novella. Low-energy dithiolene --> Mo and cysteine thiolate --> Mo charge-transfer bands have been assigned for the first time in a Mo(V) form of a SUOX fold protein, and the spectroscopic data have been used to interpret the results of bonding calculations. The analysis shows that second coordination sphere effects modulate dithiolene and cysteine sulfur covalency contributions to the Mo bonding scheme. In particular, a more acute O(oxo)-Mo-S(Cys)-C dihedral angle results in increased cysteine thiolate S --> Mo charge transfer and a large g(1) in the EPR spectrum. The spectrosocopic results, coupled with the available structural data, indicate that these second coordination sphere effects may play key roles in modulating the active-site redox potential, facilitating hole superexchange pathways for electron transfer regeneration, and affecting the type of reactions catalyzed by sulfite oxidase family enzymes.
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Affiliation(s)
- Jing Yang
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, USA
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Alfaro JF, Joswig-Jones CA, Ouyang W, Nichols J, Crouch GJ, Jones JP. Purification and mechanism of human aldehyde oxidase expressed in Escherichia coli. Drug Metab Dispos 2009; 37:2393-8. [PMID: 19741035 DOI: 10.1124/dmd.109.029520] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Human aldehyde oxidase 1 (AOX1) has been subcloned into a vector suitable for expression in Escherichia coli, and the protein has been expressed. The resulting protein is active, with sulfur being incorporated in the molybdopterin cofactor. Expression levels are modest, but 1 liter of cells supplies enough protein for both biochemical and kinetic characterization. Partial purification is achieved by nickel affinity chromatography through the addition of six histidines to the amino-terminal end of the protein. Kinetic analysis, including kinetic isotope effects and comparison with xanthine oxidase, reveal similar mechanisms, with some subtle differences. This expression system will allow for the interrogation of human aldehyde oxidase structure/function relationships by site-directed mutagenesis and provide protein for characterizing the role of AOX1 in drug metabolism.
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Affiliation(s)
- Joshua F Alfaro
- Department of Chemistry, Washington State University, Pullman, WA 99163, USA
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Groysman S, Holm RH. Biomimetic chemistry of iron, nickel, molybdenum, and tungsten in sulfur-ligated protein sites. Biochemistry 2009; 48:2310-20. [PMID: 19206188 PMCID: PMC2765533 DOI: 10.1021/bi900044e] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biomimetic inorganic chemistry has as its primary goal the synthesis of molecules that approach or achieve the structures, oxidation states, and electronic and reactivity features of native metal-containing sites of variant nuclearity. Comparison of properties of accurate analogues and these sites ideally provides insight into the influence of protein structure and environment on intrinsic properties as represented by the analogue. For polynuclear sites in particular, the goal provides a formidable challenge for, with the exception of iron-sulfur clusters, all such site structures have never been achieved and few have even been closely approximated by chemical synthesis. This account describes the current status of the synthetic analogue approach as applied to the mononuclear sites in certain molybdoenzymes and the polynuclear sites in hydrogenases, nitrogenase, and carbon monoxide dehydrogenases.
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Affiliation(s)
- Stanislav Groysman
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - R. H. Holm
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
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Bayse CA. Density-functional theory models of xanthine oxidoreductase activity: comparison of substrate tautomerization and protonation. Dalton Trans 2009:2306-14. [DOI: 10.1039/b821878a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tano H, Tajima R, Miyake H, Itoh S, Sugimoto H. Selenidobis(dithiolene)metal(IV) Complexes (Metal M = Mo, W) Potentially Related to the Nicotinic Acid Hydroxylase Reaction Center: Redox Aspects in Electrochemistry and Oxygen Atom Transfer from Me3NO to MIV Centers. Inorg Chem 2008; 47:7465-7. [DOI: 10.1021/ic8009942] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroyuki Tano
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Reiko Tajima
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hiroyuki Miyake
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shinobu Itoh
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hideki Sugimoto
- Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
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