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Bhadra M, Albert T, Franke A, Josef V, Ivanović-Burmazović I, Swart M, Moënne-Loccoz P, Karlin KD. Reductive Coupling of Nitric Oxide by Cu(I): Stepwise Formation of Mono- and Dinitrosyl Species En Route to a Cupric Hyponitrite Intermediate. J Am Chem Soc 2023; 145:2230-2242. [PMID: 36652374 PMCID: PMC10122266 DOI: 10.1021/jacs.2c09874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Transition-metal-mediated reductive coupling of nitric oxide (NO(g)) to nitrous oxide (N2O(g)) has significance across the fields of industrial chemistry, biochemistry, medicine, and environmental health. Herein, we elucidate a density functional theory (DFT)-supplemented mechanism of NO(g) reductive coupling at a copper-ion center, [(tmpa)CuI(MeCN)]+ (1) {tmpa = tris(2-pyridylmethyl)amine}. At -110 °C in EtOH (<-90 °C in MeOH), exposing 1 to NO(g) leads to a new binuclear hyponitrite intermediate [{(tmpa)CuII}2(μ-N2O22-)]2+ (2), exhibiting temperature-dependent irreversible isomerization to the previously characterized κ2-O,O'-trans-[(tmpa)2Cu2II(μ-N2O22-)]2+ (OOXray) complex. Complementary stopped-flow kinetic analysis of the reaction in MeOH reveals an initial mononitrosyl species [(tmpa)Cu(NO)]+ (1-(NO)) that binds a second NO molecule, forming a dinitrosyl species [(tmpa)CuII(NO)2] (1-(NO)2). The decay of 1-(NO)2 requires an available starting complex 1 to form a dicopper-dinitrosyl species hypothesized to be [{(tmpa)Cu}2(μ-NO)2]2+ (D) bearing a diamond-core motif, en route to the formation of hyponitrite intermediate 2. In contrast, exposing 1 to NO(g) in 2-MeTHF/THF (v/v 4:1) at <-80 °C leads to the newly observed transient metastable dinitrosyl species [(tmpa)CuII(NO)2] (1-(NO)2) prior to its disproportionation-mediated transformation to the nitrite product [(tmpa)CuII(NO2)]+. Our study furnishes a near-complete profile of NO(g) activation at a reduced Cu site with tripodal tetradentate ligation in two distinctly different solvents, aided by detailed spectroscopic characterization of metastable intermediates, including resonance Raman characterization of the new dinitrosyl and hyponitrite species detected.
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Affiliation(s)
- Mayukh Bhadra
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Alicja Franke
- Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
- Department of Chemistry, Ludwig-Maximilians University, Munich, 81377 Munich, Germany
| | - Verena Josef
- Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Ivana Ivanović-Burmazović
- Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
- Department of Chemistry, Ludwig-Maximilians University, Munich, 81377 Munich, Germany
| | - Marcel Swart
- IQCC & Departament de Química, Universitat de Girona, Campus Montilivi (Ciencies), 17003 Girona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, United States
| | - Kenneth D Karlin
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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Varotsis C, Tselios C, Yiannakkos KA, Andreou C, Papageorgiou M, Nicolaides A. Application of double-pulse laser-induced breakdown spectroscopy (DP-LIBS), Fourier transform infrared micro-spectroscopy and Raman microscopy for the characterization of copper-sulfides. RSC Adv 2021; 12:631-639. [PMID: 35425097 PMCID: PMC8978887 DOI: 10.1039/d1ra07189k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 12/14/2021] [Indexed: 12/28/2022] Open
Abstract
The combined application of the structure sensitive techniques Fourier transform infrared μ-spectroscopy and Raman microscopy in conjunction with different approaches of laser-induced breakdown spectroscopy (LIBS) including the two-color double pulse (DP-LIBS) have been applied towards the characterization of whole ore copper-sulfide minerals. Discrete information from the surface of the whole ore minerals that lead to the establishment of infrared marker bands and from the surface of bioleached samples that allow the monitoring of jarosite and biofilm formation are provided by FTIR mapping experiments. Raman data can provide information related to the type of the mineral and of the secondary minerals formed on the surface of the ore. Of the four different LIBS approaches applied towards the characterization of the composition of the whole ore minerals, the DP-LIBS shows the highest sensitivity with increasing signals for both the Fe and Cu metals in the whole ore samples. Raman and FTIR microspectroscopies, laser induced breakdown spectroscopy (LIBS) and DP-LIBS have been applied towards our understanding of the characterization of the structure and structure–function relationship in copper-sulfide minerals.![]()
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Affiliation(s)
- Constantinos Varotsis
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
| | - Charalampos Tselios
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
| | - Konstantinos A Yiannakkos
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
| | - Charalampos Andreou
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
| | - Marios Papageorgiou
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
| | - Antonis Nicolaides
- Department of Chemical Engineering, Cyprus University of Technology Eirinis 95 Limassol 3041 Cyprus +357 25002802
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Lehnert N, Kim E, Dong HT, Harland JB, Hunt AP, Manickas EC, Oakley KM, Pham J, Reed GC, Alfaro VS. The Biologically Relevant Coordination Chemistry of Iron and Nitric Oxide: Electronic Structure and Reactivity. Chem Rev 2021; 121:14682-14905. [PMID: 34902255 DOI: 10.1021/acs.chemrev.1c00253] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule that is involved in a wide range of physiological and pathological events in biology. Metal coordination chemistry, especially with iron, is at the heart of many biological transformations involving NO. A series of heme proteins, nitric oxide synthases (NOS), soluble guanylate cyclase (sGC), and nitrophorins, are responsible for the biosynthesis, sensing, and transport of NO. Alternatively, NO can be generated from nitrite by heme- and copper-containing nitrite reductases (NIRs). The NO-bearing small molecules such as nitrosothiols and dinitrosyl iron complexes (DNICs) can serve as an alternative vehicle for NO storage and transport. Once NO is formed, the rich reaction chemistry of NO leads to a wide variety of biological activities including reduction of NO by heme or non-heme iron-containing NO reductases and protein post-translational modifications by DNICs. Much of our understanding of the reactivity of metal sites in biology with NO and the mechanisms of these transformations has come from the elucidation of the geometric and electronic structures and chemical reactivity of synthetic model systems, in synergy with biochemical and biophysical studies on the relevant proteins themselves. This review focuses on recent advancements from studies on proteins and model complexes that not only have improved our understanding of the biological roles of NO but also have provided foundations for biomedical research and for bio-inspired catalyst design in energy science.
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Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hai T Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B Harland
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Andrew P Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Elizabeth C Manickas
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Kady M Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - John Pham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Garrett C Reed
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Victor Sosa Alfaro
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Papageorgiou M, Tselios C, Varotsis C. Photoreduction of carotenoids in the aerobic anoxygenic photoheterotrophs probed by real time Raman spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 213:112069. [PMID: 33152639 DOI: 10.1016/j.jphotobiol.2020.112069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 11/28/2022]
Abstract
The Aerobic anoxygenic phototrophic bacteria (AAPB) Roseobacter denitrificans and Roseobacter litoralis are widespread in the bacterioplankton community with a particular role in the marine carbon cycle. Measurements of carotenoids isolated from dark-grown cells indicated the presence of spheroidenone (SO, N = 11) and of 3,4 dihydrospheroidenone (N = 10) in the carotenoids isolated from illuminated cells. Time-dependent Raman 514 nm excitation experiments of R. denitrificans and R. litoralis cells grown under illumination demonstrated that v1 (C=C) of SO exhibits a time-dependent substantial frequency upshift relative to its frequency in the dark-grown cells, in a manner resembling shorting the conjugation length (N). We suggest that the irreversible dark-SO to light- 3,4 dihydrospheroidenone transition observed in the intact carotenoids of R. denitrificans and R. litoralis cells is an operative photoreduction strategy of SO containing AAPB that affects the energy transfer mechanism.
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Affiliation(s)
- Marios Papageorgiou
- Department of Chemical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Charalampos Tselios
- Department of Chemical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Constantinos Varotsis
- Department of Chemical Engineering, Cyprus University of Technology, Limassol, Cyprus.
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Wijeratne GB, Bhadra M, Siegler MA, Karlin KD. Copper(I) Complex Mediated Nitric Oxide Reductive Coupling: Ligand Hydrogen Bonding Derived Proton Transfer Promotes N 2O (g) Release. J Am Chem Soc 2019; 141:17962-17967. [PMID: 31621325 DOI: 10.1021/jacs.9b07286] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A cuprous chelate bearing a secondary sphere hydrogen bonding functionality, [(PV-tmpa)CuI]+, transforms •NO(g) to N2O(g) in high-yields in methanol. Ligand derived proton transfer facilitates N-O bond cleavage of a putative hyponitrite intermediate releasing N2O(g), underscoring the crucial balance between H-bonding capabilities and acidities in (bio)chemical •NO(g) coupling systems.
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Affiliation(s)
- Gayan B Wijeratne
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Mayukh Bhadra
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Maxime A Siegler
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Kenneth D Karlin
- Department of Chemistry , The Johns Hopkins University , Baltimore , Maryland 21218 , United States
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Tselios C, Papageorgiou M, Varotsis C. Extracellular electron uptake from carbon-based π electron surface-donors: oxidation of graphite sheets by Sulfobacillus thermosulfidooxidans probed by Raman and FTIR spectroscopies. RSC Adv 2019; 9:19121-19125. [PMID: 35516881 PMCID: PMC9065002 DOI: 10.1039/c9ra03628h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/12/2019] [Indexed: 11/21/2022] Open
Abstract
In this work we report Raman and FTIR evidence for extracellular electron uptake by Sulfobacillus thermosulfidooxidans from the solid phase carbon-based π-electron donor surface of graphite sheets. The primary step in the reaction is the intercalation of water on the surface of graphite followed by the formation of EPS and proceeds to form graphite oxide (GO) with a Raman I D/I G = 0.3 ratio which represents the highest defect content in the carbon lattice reported by bio-oxidation process. We propose and discuss a direct extracellular electron transfer mechanism via outer membrane redox proteins for the electron transfer.
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Affiliation(s)
- Charalampos Tselios
- Cyprus University of Technology, Department of Environmental Science and Technology Lemesos Cyprus +357 25002802
| | - Marios Papageorgiou
- Cyprus University of Technology, Department of Environmental Science and Technology Lemesos Cyprus +357 25002802
| | - Constantinos Varotsis
- Cyprus University of Technology, Department of Environmental Science and Technology Lemesos Cyprus +357 25002802
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Koutsoupakis C, Soulimane T, Varotsis C. Discrete Ligand Binding and Electron Transfer Properties of ba 3-Cytochrome c Oxidase from Thermus thermophilus: Evolutionary Adaption to Low Oxygen and High Temperature Environments. Acc Chem Res 2019; 52:1380-1390. [PMID: 31021078 DOI: 10.1021/acs.accounts.9b00052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome c oxidase (C cO) couples the oxidation of cytochrome c to the reduction of molecular oxygen to water and links these electron transfers to proton translocation. The redox-driven C cO conserves part of the released free energy generating a proton motive force that leads to the synthesis of the main biological energy source ATP. Cytochrome ba3 oxidase is a B-type oxidase from the extremely thermophilic eubacterium Thermus thermophilus with high O2 affinity, expressed under elevated temperatures and limited oxygen supply and possessing discrete structural, ligand binding, and electron transfer properties. The origin and the cause of the peculiar, as compared to other C cOs, thermodynamic and kinetic properties remain unknown. Fourier transform infrared (FTIR) and time-resolved step-scan FTIR (TRS2-FTIR) spectroscopies have been employed to investigate the origin of the binding and electron transfer properties of cytochrome ba3 oxidase in both the fully reduced (FR) and mixed valence (MV) forms. Several independent and not easily separated factors leading to increased thermostability and high O2 affinity have been determined. These include (i) the increased hydrophobicity of the active center, (ii) the existence of a ligand input channel, (iii) the high affinity of CuB for exogenous ligands, (iv) the optimized electron transfer (ET) pathways, (v) the effective proton-input channel and water-exit pathway as well the proton-loading/exit sites, (vi) the specifically engineered protein structure, and (vii) the subtle thermodynamic and kinetic regulation. We correlate the unique ligand binding and electron transfer properties of cytochrome ba3 oxidase with the existence of an adaption mechanism which is necessary for efficient function. These results suggest that a cascade of structural factors have been optimized by evolution, through protein architecture, to ensure the conversion of cytochrome ba3 oxidase into a high O2-affinity enzyme that functions effectively in its extreme native environment. The present results show that ba3-cytochrome c oxidase uses a unique structural pattern of energy conversion that has taken into account all the extreme environmental factors that affect the function of the enzyme and is assembled in such a way that its exclusive functions are secured. Based on the available data of CcOs, we propose possible factors including the rigidity and nonpolar hydrophobic interactions that contribute to the behavior observed in cytochrome ba3 oxidase.
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Affiliation(s)
- Constantinos Koutsoupakis
- Department of Environmental Science and Technology, Cyprus University of Technology, P.O. Box 50329, 3603 Lemesos, Cyprus
| | - Tewfik Soulimane
- Chemical and Environmental Science Department and Materials & Surface Science Institute (MSSI), University of Limerick, Limerick, Ireland
| | - Constantinos Varotsis
- Department of Environmental Science and Technology, Cyprus University of Technology, P.O. Box 50329, 3603 Lemesos, Cyprus
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Papageorgiou M, Tselios C, Varotsis C. Photosensitivity responses ofSagittula stellataprobed by FTIR, fluorescence and Raman microspectroscopy. RSC Adv 2019; 9:27391-27397. [PMID: 35529232 PMCID: PMC9070597 DOI: 10.1039/c9ra03630j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/26/2019] [Indexed: 12/05/2022] Open
Abstract
Raman, fluorescence and FTIR experiments of prestine Sagittula stellata and Sagittula stellata–metal ion complexes grown in light and in dark were performed to probe the photosensitivity response of the cellular components in the marine bacterium. In the presence of Cu(ii) and Zn(ii) the frequency shifts of PO2−, C–O–C and C–O–P vibrations indicate metal binding to nucleic acids, carbohydrates and polysaccharides. We assign the observed bands in the 514.1 nm Raman spectra of the prestine S. Stellata and of the extracted carotenoids to the C
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C and C–C stretching vibrations. The fluorescence excitation–emission matrix (EEM) of S. stellata in light, dark and in the presence of metal ions are reported and compared with the Raman and FTIR data. The novel ability of S. stellata although heterotrophic, to show light-dependent metal binding ability may be an important feature property that maintains a stable heterotroph–prototroph interaction and a dynamic system. Raman, fluorescence and FTIR experiments of prestine Sagittula stellata and Sagittula stellata–metal ion complexes grown in light and in dark were performed to probe the photosensitivity response of the cellular components in the marine bacterium.![]()
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Affiliation(s)
- Marios Papageorgiou
- Department of Environmental Science and Technology
- Cyprus University of Technology
- Lemesos
- Cyprus
| | - Charalampos Tselios
- Department of Environmental Science and Technology
- Cyprus University of Technology
- Lemesos
- Cyprus
| | - Constantinos Varotsis
- Department of Environmental Science and Technology
- Cyprus University of Technology
- Lemesos
- Cyprus
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Blomberg MRA, Ädelroth P. Mechanisms for enzymatic reduction of nitric oxide to nitrous oxide - A comparison between nitric oxide reductase and cytochrome c oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1223-1234. [PMID: 30248312 DOI: 10.1016/j.bbabio.2018.09.368] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/23/2018] [Accepted: 09/17/2018] [Indexed: 12/22/2022]
Abstract
Cytochrome c oxidases (CcO) reduce O2 to H2O in the respiratory chain of mitochondria and many aerobic bacteria. In addition, some species of CcO can also reduce NO to N2O and water while others cannot. Here, the mechanism for NO-reduction in CcO is investigated using quantum mechanical calculations. Comparison is made to the corresponding reaction in a "true" cytochrome c-dependent NO reductase (cNOR). The calculations show that in cNOR, where the reduction potentials are low, the toxic NO molecules are rapidly reduced, while the higher reduction potentials in CcO lead to a slower or even impossible reaction, consistent with experimental observations. In both enzymes the reaction is initiated by addition of two NO molecules to the reduced active site, forming a hyponitrite intermediate. In cNOR, N2O can then be formed using only the active-site electrons. In contrast, in CcO, one proton-coupled reduction step most likely has to occur before N2O can be formed, and furthermore, proton transfer is most likely rate-limiting. This can explain why different CcO species with the same heme a3-Cu active site differ with respect to NO reduction efficiency, since they have a varying number and/or properties of proton channels. Finally, the calculations also indicate that a conserved active site valine plays a role in reducing the rate of NO reduction in CcO.
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Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden.
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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Wijeratne GB, Hematian S, Siegler MA, Karlin KD. Copper(I)/NO (g) Reductive Coupling Producing a trans-Hyponitrite Bridged Dicopper(II) Complex: Redox Reversal Giving Copper(I)/NO (g) Disproportionation. J Am Chem Soc 2017; 139:13276-13279. [PMID: 28820592 PMCID: PMC5630263 DOI: 10.1021/jacs.7b07808] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A copper complex, [CuI(tmpa)(MeCN)]+, effectively reductively couples NO(g) at RT in methanol (MeOH), giving a structurally characterized hyponitrito-dicopper(II) adduct. Hydrogen-bonding from MeOH is critical for the hyponitrite complex formation and stabilization. This complex exhibits the reverse redox process in aprotic solvents, giving CuI + NO(g), leading to CuI-mediated NO(g)-disproportionation. The relationship of this chemistry to biological iron and/or copper mediated NO(g) reductive coupling to give N2O(g) is discussed.
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Affiliation(s)
| | | | - Maxime A. Siegler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Yi J, Campbell ALO, Richter-Addo GB. Nitric oxide coupling to generate N 2O promoted by a single-heme system as examined by density functional theory. Nitric Oxide 2016; 60:69-75. [PMID: 27646954 DOI: 10.1016/j.niox.2016.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/11/2016] [Accepted: 09/14/2016] [Indexed: 11/25/2022]
Abstract
Bacteria utilize a heme/non-heme enzyme system to detoxify nitric oxide (NO) to N2O. In order to probe the capacity of a single-heme system to mediate this NO-to-N2O transformation, various scenarios for addition of electrons, protons, and a second NO molecule to a heme nitrosyl to generate N2O were explored by density functional theory calculations. We describe, utilizing this single-heme system, several stepwise intermediates along pathways that enable the critical N-N bond formation step yielding the desired Fe-N2O product. We also report a hitherto unreported directional second protonation that results in either productive N2O formation with loss of water, or formation of a non-productive hyponitrous acid adduct Fe{HONNOH}.
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Affiliation(s)
- Jun Yi
- Department of Biological Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei Road, Nanjing, Jiangsu Province, 210094, PR China; Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, 73019, USA.
| | - Adam L O Campbell
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, 73019, USA
| | - George B Richter-Addo
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, 73019, USA.
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Lionetti D, de Ruiter G, Agapie T. A trans-Hyponitrite Intermediate in the Reductive Coupling and Deoxygenation of Nitric Oxide by a Tricopper-Lewis Acid Complex. J Am Chem Soc 2016; 138:5008-11. [PMID: 27028157 DOI: 10.1021/jacs.6b01083] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reduction of nitric oxide (NO) to nitrous oxide (N2O) is a process relevant to biological chemistry as well as to the abatement of certain environmental pollutants. One of the proposed key intermediates in NO reduction is hyponitrite (N2O2(2-)), the product of reductive coupling of two NO molecules. We report the reductive coupling of NO by an yttrium-tricopper complex generating a trans-hyponitrite moiety supported by two μ-O-bimetallic (Y,Cu) cores, a previously unreported coordination mode. Reaction of the hyponitrite species with Brønsted acids leads to the generation of N2O, demonstrating the viability of the hyponitrite complex as an intermediate in NO reduction to N2O. The additional reducing equivalents stored in each tricopper unit are employed in a subsequent step for N2O reduction to N2, for an overall (partial) conversion of NO to N2. The combination of Lewis acid and multiple redox active metals facilitates this four electron conversion via an isolable hyponitrite intermediate.
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Affiliation(s)
- Davide Lionetti
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
| | - Graham de Ruiter
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, MC 127-72, Pasadena, California 91125, United States
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Suzuki T, Tanaka H, Shiota Y, Sajith PK, Arikawa Y, Yoshizawa K. Proton-Assisted Mechanism of NO Reduction on a Dinuclear Ruthenium Complex. Inorg Chem 2015; 54:7181-91. [PMID: 26186365 DOI: 10.1021/acs.inorgchem.5b00394] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Density-functional-theory (DFT) calculations are performed for the proposal of a plausible mechanism on the reduction of NO to N2O by a dinuclear ruthenium complex, reported by Arikawa and co-workers [J. Am. Chem. Soc. 2007, 129, 14160]. On the basis of the experimental fact that the reduction proceeds under strongly acidic conditions, the role of protons in the mechanistic pathways is investigated with model complexes, where one or two NO ligands are protonated. The reaction mechanism of the NO reduction is partitioned into three steps: reorientation of N2O2 (cis-NO dimer), O-N bond cleavage, and N2O elimination. A key finding is that the protonation of the NO ligand(s) significantly reduces the activation barrier in the rate-determining reorientation step. The activation energy of 43.1 kcal/mol calculated for the proton-free model is reduced to 30.2 and 17.6 kcal/mol for the mono- and diprotonated models, respectively. The protonation induces the electron transfer from the Ru(II)Ru(II) core to the O═N-N═O moiety to give a Ru(III)Ru(III) core and a hyponitrite (O-N═N-O)(2-) species. The formation of the hyponitrite species provides an alternative pathway for the N2O2 reorientation, resulting in the lower activation energies in the presence of proton(s). The protonation also has a marginal effect on the O-N bond cleavage and the N2O elimination steps. Our calculations reveal a remarkable role of protons in the NO reduction via N2O formation and provide new insights into the mechanism of NO reduction catalyzed by metalloenzymes such as nitric oxide reductase (NOR) that contains a diiron active site.
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Affiliation(s)
- Tatsuya Suzuki
- †Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hiromasa Tanaka
- ‡Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Nishikyo-ku, Kyoto 615-8245, Japan
| | - Yoshihito Shiota
- †Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - P K Sajith
- †Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yasuhiro Arikawa
- §Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo-machi 1-14, Nagasaki 852-8521, Japan
| | - Kazunari Yoshizawa
- †Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan.,‡Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Nishikyo-ku, Kyoto 615-8245, Japan
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14
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Koutsoupakis C, Soulimane T, Varotsis C. Photobiochemical production of carbon monoxide by Thermus thermophilus ba3 -cytochrome c oxidase. Chemistry 2015; 21:4958-61. [PMID: 25689606 DOI: 10.1002/chem.201406239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Indexed: 11/08/2022]
Abstract
We report the photobiochemical production of carbon monoxide by a terminal ba3 -cytochrome c oxidase from T. thermophilus HB8. FTIR and time-resolved step-scan FTIR spectroscopies were combined to probe this process and also monitor the concomitant binding of the produced gas to other intact ba3 molecules forming the ba3 -CO complex. The activation of this mechanism by ba3 -oxidase under visible excitation raises the question as to whether such a mechanism is physiologically relevant to the extreme environment in which it operates.
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Affiliation(s)
- Constantinos Koutsoupakis
- Department of Environmental Science and Technology, Cyprus University of Technology, P.O. Box 50329, 3603 Lemesos (Cyprus)
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15
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Ohta T, Soulimane T, Kitagawa T, Varotsis C. Nitric oxide activation by caa3 oxidoreductase from Thermus thermophilus. Phys Chem Chem Phys 2015; 17:10894-8. [DOI: 10.1039/c5cp01013f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present UV-Raman evidence for the formation of the hyponitrite (HO–NN–O−) species in the binuclear heme a3 Fe–CuB center (νN–N = 1330 cm−1) of caa3 heme-copper oxidoreductase from Thermus thermophilus.
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Affiliation(s)
- Takehiro Ohta
- Graduate School of Life Science
- University of Hyogo
- Hyogo 678-1297
- Japan
| | - Tewfik Soulimane
- Chemical & Environmental Sciences Department and Materials & Surface Science Institute
- University of Limerick
- Limerick
- Ireland
| | - Teizo Kitagawa
- Graduate School of Life Science
- University of Hyogo
- Hyogo 678-1297
- Japan
| | - Constantinos Varotsis
- Cyprus University of Technology
- Department of Environmental Science and Technology
- 3603 Lemesos
- Cyprus
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16
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Loullis A, Noor MR, Soulimane T, Pinakoulaki E. Observation of ligand transfer in ba3 oxidase from Thermus thermophilus: simultaneous FTIR detection of photolabile heme a3(2+)-CN and transient Cu(B)(2+)-CN complexes. J Phys Chem B 2012; 116:8955-60. [PMID: 22765881 DOI: 10.1021/jp305096y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
FTIR and light-minus-dark FTIR spectroscopy have been employed to investigate the reaction of oxidized and fully reduced ba(3) oxidase with cyanide. The characterization of the structures of the bound CN(-) in the binuclear heme Fe-Cu(B) center is essential, given that a central issue in the function of ba(3) oxidase is the extent to which the partially reduced substrates interact with the two metals. In the reaction of oxidized ba(3) oxidase with cyanide the initially formed heme a(3)(3+)-C≡N-Cu(B)(2+) species with ν(CN) frequency at 2152 cm(-1) was replaced by a photolabile complex with a frequency at 2075 cm(-1) characteristic of heme a(3)(2+)-CN(-). Photolysis of the heme a(3)(2+)-CN(-) adduct produced a band at 2146 cm(-1) attributed to the formation of a transient Cu(B)(2+)-CN(-) complex. All forms are pH independent between pH 5.5-9.5 and at pD 7.5 indicating the absence of ionizable groups that influence the properties of the cyanide complexes. In contrast to previous reports, our results show that CN(-) does not bind simultaneously to both heme a(3)(2+) and Cu(B)(2+) to form the mixed valence a(3)(2+)-CN·Cu(B)(2+)CN species. The photolysis products of the heme a(3)(2+)-CN(-)/Cu(B)(2+) and heme a(3)(2+)-CN(-)/Cu(B)(1+) species are different suggesting that relaxation dynamics in the binuclear center following ligand photodissociation are dependent on the oxidation state of Cu(B).
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Affiliation(s)
- Andreas Loullis
- Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
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17
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Mayer T, Böttcher HC. Reduktive Dimerisierung von NO an Dirutheniumkomplexen und Bildung eines tridentaten 2, 2-Bis(diphenylphosphanyl)ethanolato-Liganden. Z Anorg Allg Chem 2012. [DOI: 10.1002/zaac.201200073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Arikawa Y, Onishi M. Reductive N–N coupling of NO molecules on transition metal complexes leading to N2O. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.10.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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19
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Reductive NO dimerization to trans-hyponitrite in diruthenium complexes: Intramolecular attack of hyponitrite on a CO ligand. J Organomet Chem 2012. [DOI: 10.1016/j.jorganchem.2011.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Mayer T, Böttcher HC. Crystal and Molecular Structure of the trans-Hyponitrite Compounds Ph3E(μ-ONNO)EPh3 (E = Ge, Pb). Z Anorg Allg Chem 2012. [DOI: 10.1002/zaac.201100543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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21
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Böttcher HC, Mayer T. Synthese und Kristallstruktur von [Ru2(CO)4(μ-H)(μ-NO)(μ-PtBu2)(μ-PPh2CH2PPh2)]BF4. Z Anorg Allg Chem 2011. [DOI: 10.1002/zaac.201100226] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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Mayer T, Beck W, Böttcher HC. Crystal and Molecular Structure of the trans-Hyponitrite Compound Ph3Sn(μ-ONNO)SnPh3. Z Anorg Allg Chem 2011. [DOI: 10.1002/zaac.201000444] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Ghosh Dey S, Dey A. NO and O2 reactivities of synthetic functional models of nitric oxide reductase and cytochrome c oxidase. Dalton Trans 2011; 40:12633-47. [DOI: 10.1039/c1dt10451a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Arikawa Y, Matsumoto N, Asayama T, Umakoshi K, Onishi M. Conversion of oxido-bridged dinuclear ruthenium complex to dicationic dinitrosyl ruthenium complex using proton and nitric oxide: Completion of NO reduction cycle. Dalton Trans 2011; 40:2148-50. [DOI: 10.1039/c0dt01002b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Xu N, Yi J, Richter-Addo GB. Linkage isomerization in heme-NOx compounds: understanding NO, nitrite, and hyponitrite interactions with iron porphyrins. Inorg Chem 2010; 49:6253-66. [PMID: 20666385 DOI: 10.1021/ic902423v] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Nitric oxide (NO) and its derivatives such as nitrite and hyponitrite are biologically important species of relevance to human health. Much of their physiological relevance stems from their interactions with the iron centers in heme proteins. The chemical reactivities displayed by the heme-NOx species (NOx = NO, nitrite, hyponitrite) are a function of the binding modes of the NOx ligands. Hence, an understanding of the types of binding modes extant in heme-NOx compounds is important if we are to unravel the inherent chemical properties of these NOx metabolites. In this Forum Article, the experimentally characterized linkage isomers of heme-NOx models and proteins are presented and reviewed. Nitrosyl linkage isomers of synthetic iron and ruthenium porphyrins have been generated by photolysis at low temperatures and characterized by spectroscopy and density functional theory calculations. Nitrite linkage isomers in synthetic metalloporphyrin derivatives have been generated from photolysis experiments and in low-temperature matrices. In the case of nitrite adducts of heme proteins, both N and O binding have been determined crystallographically, and the role of the distal H-bonding residue in myoglobin in directing the O-binding mode of nitrite has been explored using mutagenesis. To date, only one synthetic metalloporphyrin complex containing a hyponitrite ligand (displaying an O-binding mode) has been characterized by crystallography. This is contrasted with other hyponitrite binding modes experimentally determined for coordination compounds and computationally for NO reductase enzymes. Although linkage isomerism in heme-NOx derivatives is still in its infancy, opportunities now exist for a detailed exploration of the existence and stabilities of the metastable states in both heme models and heme proteins.
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Affiliation(s)
- Nan Xu
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019, USA
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Wang J, Schopfer MP, Puiu SC, Sarjeant AAN, Karlin KD. Reductive coupling of nitrogen monoxide (*NO) facilitated by heme/copper complexes. Inorg Chem 2010; 49:1404-19. [PMID: 20030370 DOI: 10.1021/ic901431r] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The interactions of nitrogen monoxide (*NO; nitric oxide) with transition metal centers continue to be of great interest, in part due to their importance in biochemical processes. Here, we describe *NO((g)) reductive coupling chemistry of possible relevance to that process (i.e., nitric oxide reductase (NOR) biochemistry), which occurs at the heme/Cu active site of cytochrome c oxidases (CcOs). In this report, heme/Cu/*NO((g)) activity is studied using 1:1 ratios of heme and copper complex components, (F(8))Fe (F(8) = tetrakis(2,6-difluorophenyl)porphyrinate(2-)) and [(tmpa)Cu(I)(MeCN)](+) (TMPA = tris(2-pyridylmethyl)amine). The starting point for heme chemistry is the mononitrosyl complex (F(8))Fe(NO) (lambda(max) = 399 (Soret), 541 nm in acetone). Variable-temperature (1)H and (2)H NMR spectra reveal a broad peak at delta = 6.05 ppm (pyrrole) at room temperature (RT), which gives rise to asymmetrically split pyrrole peaks at 9.12 and 8.54 ppm at -80 degrees C. A new heme dinitrosyl species, (F(8))Fe(NO)(2), obtained by bubbling (F(8))Fe(NO) with *NO((g)) at -80 degrees C, could be reversibly formed, as monitored by UV-vis (lambda(max) = 426 (Soret), 538 nm in acetone), EPR (silent), and NMR spectroscopies; that is, the mono-NO complex was regenerated upon warming to RT. (F(8))Fe(NO)(2) reacts with [(tmpa)Cu(I)(MeCN)](+) and 2 equiv of acid to give [(F(8))Fe(III)](+), [(tmpa)Cu(II)(solvent)](2+), and N(2)O((g)), fitting the stoichiometric *NO((g)) reductive coupling reaction: 2*NO((g)) + Fe(II) + Cu(I) + 2H(+) --> N(2)O((g)) + Fe(III) + Cu(II) + H(2)O, equivalent to one enzyme turnover. Control reaction chemistry shows that both iron and copper centers are required for the NOR-type chemistry observed and that, if acid is not present, half the *NO is trapped as a (F(8))Fe(NO) complex, while the remaining nitrogen monoxide undergoes copper complex promoted disproportionation chemistry. As part of this study, [(F(8))Fe(III)]SbF(6) was synthesized and characterized by X-ray crystallography, along with EPR (77 K: g = 5.84 and 6.12 in CH(2)Cl(2) and THF, respectively) and variable-temperature NMR spectroscopies. These structural and physical properties suggest that at RT this complex consists of an admixture of high and intermediate spin states.
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Affiliation(s)
- Jun Wang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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27
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Böttcher HC, Mayer P. Hyponitrite complexes: Crystal and molecular structure of [Ru2(CO)4(μ-PtBu2)(μ-Ph2PCH2PPh2)(μ-η2-ONNOMe)]. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2009.11.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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O2 reduction by a functional heme/nonheme bis-iron NOR model complex. Proc Natl Acad Sci U S A 2009; 106:10528-33. [PMID: 19541624 DOI: 10.1073/pnas.0904634106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
O(2) reactivity of a functional NOR model is investigated by using electrochemistry and spectroscopy. The electrochemical measurements using interdigitated electrodes show very high selectivity for 4e O(2) reduction with minimal production of partially reduced oxygen species (PROS) under both fast and slow electron flux. Intermediates trapped at cryogenic temperatures and characterized by using resonance Raman spectroscopy under single-turnover conditions indicate that an initial bridging peroxide intermediate undergoes homolytic O--O bond cleavage generating a trans heme/nonheme bis-ferryl intermediate. This bis ferryl species can oxygenate 2 equivalents of a reactive substrate.
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29
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Wang J, Schopfer MP, Sarjeant AAN, Karlin KD. Heme-copper assembly mediated reductive coupling of nitrogen monoxide (*NO). J Am Chem Soc 2009; 131:450-1. [PMID: 19099478 DOI: 10.1021/ja8084324] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A iron-dinitrosyl species ((6)L)Fe(NO)(2) (2), generated from nitrogen monoxide (*NO) binding to its related iron(II)-mononitrosyl complex ((6)L)Fe(NO) (1), efficiently effects reductive coupling of two *NO molecules to release nitrous oxide (N(2)O), when Cu(+) ion and 2 equiv acid are added; the heme/Cu product is [((6)L)Fe(III)...Cu(II)(D)](3+) (D = H(2)O or MeCN). In a control experiment where only ((6)L)Fe(NO)(2) (2) is exposed to 2 equiv acid, no UV-vis change is observed; upon warming, *NO((g)) is released and ((6)L)Fe(NO) is reformed. The copper ion complex within the (6)L ligand framework is required for the *NO coupling chemistry. In a further control experiment Cu(+) ion is added to ((6)L)Fe(NO)(2) without acid present, [((6)L)Fe(NO)...Cu(II)(NO(2)(-))](+) is obtained, with the amount of N(2)O((g)) released fitting with copper(I) ion promoted disproportionation chemistry, 3*NO + ligand-Cu(I) --> N(2)O + ligand-Cu(II)(NO(2)(-)). The chemical system described represents a (stoichiometric) functional model for heme/Cu protein nitric oxide reductase activity.
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Affiliation(s)
- Jun Wang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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30
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Abstract
A functional heme/nonheme nitric oxide reductase (NOR) model is presented. The fully reduced diiron compound reacts with two equivalents of NO leading to the formation of one equivalent of N(2)O and the bis-ferric product. NO binds to both heme Fe and nonheme Fe complexes forming individual ferrous nitrosyl species. The mixed-valence species with an oxidized heme and a reduced nonheme Fe(B) does not show NO reduction activity. These results are consistent with a so-called "trans" mechanism for the reduction of NO by bacterial NOR.
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