1
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Harland JB, Samanta S, Lehnert N. Bacterial nitric oxide reductase (NorBC) models employing click chemistry. J Inorg Biochem 2023; 246:112280. [PMID: 37352656 DOI: 10.1016/j.jinorgbio.2023.112280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/15/2023] [Accepted: 05/30/2023] [Indexed: 06/25/2023]
Abstract
Bacterial NO Reductase (NorBC or cNOR) is a membrane-bound enzyme found in denitrifying bacteria that catalyzes the two-electron reduction of NO to N2O and water. The mechanism by which NorBC operates is highly debated, due to the fact that this enzyme is difficult to work with, and no intermediates of the NO reduction reaction could have been identified so far. The unique active site of NorBC consists of a heme b3/non-heme FeB diiron center. Synthetic model complexes provide the opportunity to obtain insight into possible mechanistic alternatives for this enzyme. In this paper, we present three new synthetic model systems for NorBC, consisting of a tetraphenylporphyrin-derivative clicked to modified BMPA-based ligands (BMPA = bis(methylpyridyl)amine) that model the non-heme site in the enzyme. These complexes have been characterized by EPR, IR and UV-Vis spectroscopy. The reactivity with NO was then investigated, and it was found that the complex with the BMPA-carboxylate ligand as the non-heme component has a very low affinity for NO at the non-heme iron site. If the carboxylate functional group is replaced with a phenolate or pyridine group, reactivity is restored and formation of a diiron dinitrosyl complex was observed. Upon one-electron reduction of the nitrosylated complexes, following the semireduced pathway for NO reduction, formation of dinitrosyl iron complexes (DNICs) was observed in all three cases, but no N2O could be detected.
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Affiliation(s)
- Jill B Harland
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Subhra Samanta
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States.
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2
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Blomberg MRA, Ädelroth P. Reduction of Nitric Oxide to Nitrous Oxide in Flavodiiron Proteins: Catalytic Mechanism and Plausible Intermediates. ACS Catal 2023. [DOI: 10.1021/acscatal.2c04932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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3
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Ghosh P, Stauffer M, Hosseininasab V, Kundu S, Bertke JA, Cundari TR, Warren TH. NO Coupling at Copper to cis-Hyponitrite: N 2O Formation via Protonation and H-Atom Transfer. J Am Chem Soc 2022; 144:15093-15099. [PMID: 35948086 PMCID: PMC9536194 DOI: 10.1021/jacs.2c04033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Copper nitrite reductases (CuNIRs) convert NO2- to NO as well as NO to N2O under high NO flux at a mononuclear type 2 Cu center. While model complexes illustrate N-N coupling from NO that results in symmetric trans-hyponitrite [CuII]-ONNO-[CuII] complexes, we report NO assembly at a single Cu site in the presence of an external reductant Cp*2M (M = Co, Fe) to give the first copper cis-hyponitrites [Cp*2M]{[CuII](κ2-O2N2)[CuI]}. Importantly, the κ1-N-bound [CuI] fragment may be easily removed by the addition of mild Lewis bases such as CNAr or pyridine to form the spectroscopically similar anion {[CuII](κ2-O2N2)}-. The addition of electrophiles such as H+ to these anionic copper(II) cis-hyponitrites leads to N2O generation with the formation of the dicopper(II)-bis-μ-hydroxide [CuII]2(μ-OH)2. One-electron oxidation of the {[CuII](κ2-O2N2)}- core turns on H-atom transfer reactivity, enabling the oxidation of 9,10-dihydroanthracene to anthracene with concomitant formation of N2O and [CuII]2(μ-OH)2. These studies illustrate both the reductive coupling of NO at a single copper center and a way to harness the strong oxidizing power of nitric oxide via the neutral cis-hyponitrite [Cu](κ2-O2N2).
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Affiliation(s)
- Pokhraj Ghosh
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Washington, D. C. 20057, United States
| | - Molly Stauffer
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Washington, D. C. 20057, United States
| | | | - Subrata Kundu
- Department of Chemistry, Georgetown University, Washington, D. C. 20057, United States
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551, India
| | - Jeffery A. Bertke
- Department of Chemistry, Georgetown University, Washington, D. C. 20057, United States
| | - Thomas R. Cundari
- Department of Chemistry, University of North Texas, Denton, Texas 76203, United States
| | - Timothy H. Warren
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Washington, D. C. 20057, United States
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4
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Matsumura H, Faponle AS, Hagedoorn PL, Tosha T, de Visser SP, Moënne-Loccoz P. Mechanism of substrate inhibition in cytochrome-c dependent NO reductases from denitrifying bacteria (cNORs). J Inorg Biochem 2022; 231:111781. [DOI: 10.1016/j.jinorgbio.2022.111781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 12/24/2022]
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5
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Kametani Y, Abe T, Yoshizawa K, Shiota Y. Mechanistic study on reduction of nitric oxide to nitrous oxide using a dicopper complex. Dalton Trans 2022; 51:5399-5403. [PMID: 35316312 DOI: 10.1039/d2dt00275b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A density functional theory study was carried out to investigate the reduction mechanisms of NO to N2O using a dicopper complex reported by Zhang and coworkers (J. Am. Chem. Soc., 2019, 141, 10159-10164). The reaction mechanism consists of three steps: N-N bond formation, isomerization of the resultant N2O2 moiety, and cleavage of the N-O bond.
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Affiliation(s)
- Yohei Kametani
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan.
| | - Tsukasa Abe
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan.
| | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan.
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6
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Bím D, Navrátil M, Gutten O, Konvalinka J, Kutil Z, Culka M, Navrátil V, Alexandrova AN, Bařinka C, Rulíšek L. Predicting Effects of Site-Directed Mutagenesis on Enzyme Kinetics by QM/MM and QM Calculations: A Case of Glutamate Carboxypeptidase II. J Phys Chem B 2022; 126:132-143. [PMID: 34978450 DOI: 10.1021/acs.jpcb.1c09240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Quantum and molecular mechanics (QM/MM) and QM-only (cluster model) modeling techniques represent the two workhorses in mechanistic understanding of enzyme catalysis. One of the stringent tests for QM/MM and/or QM approaches is to provide quantitative answers to real-world biochemical questions, such as the effect of single-point mutations on enzyme kinetics. This translates into predicting the relative activation energies to 1-2 kcal·mol-1 accuracy; such predictions can be used for the rational design of novel enzyme variants with desired/improved characteristics. Herein, we employ glutamate carboxypeptidase II (GCPII), a dizinc metallopeptidase, also known as the prostate specific membrane antigen, as a model system. The structure and activity of this major cancer antigen have been thoroughly studied, both experimentally and computationally, which makes it an ideal model system for method development. Its reaction mechanism is quite well understood: the reaction coordinate comprises a "tetrahedral intermediate" and two transition states and experimental activation Gibbs free energy of ∼17.5 kcal·mol-1 can be inferred for the known kcat ≈ 1 s-1. We correlate experimental kinetic data (including the E424H variant, newly characterized in this work) for various GCPII mutants (kcat = 8.6 × 10-5 s-1 to 2.7 s-1) with the energy profiles calculated by QM/MM and QM-only (cluster model) approaches. We show that the near-quantitative agreement between the experimental values and the calculated activation energies (ΔH⧧) can be obtained and recommend the combination of the two protocols: QM/MM optimized structures and cluster model (QM) energetics. The trend in relative activation energies is mostly independent of the QM method (DFT functional) used. Last but not least, a satisfactory correlation between experimental and theoretical data allows us to provide qualitative and fairly simple explanations of the observed kinetic effects which are thus based on a rigorous footing.
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Affiliation(s)
- Daniel Bím
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic.,Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Michal Navrátil
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
| | - Ondrej Gutten
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
| | - Jan Konvalinka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 2120 00 Prague, Czech Republic
| | - Zsófia Kutil
- Institute of Biotechnology of the Czech Academy of Sciences, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
| | - Václav Navrátil
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Cyril Bařinka
- Institute of Biotechnology of the Czech Academy of Sciences, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
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7
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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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8
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Blomberg MRA. The importance of exact exchange-A methodological investigation of NO reduction in heme-copper oxidases. J Chem Phys 2021; 154:055103. [PMID: 33557557 DOI: 10.1063/5.0035634] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Significant improvements of the density functional theory (DFT) methodology during the past few decades have made DFT calculations a powerful tool in studies of enzymatic reaction mechanisms. For metalloenzymes, however, there are still concerns about the reliability in the DFT-results. Therefore, a systematic study is performed where the fraction of exact exchange in a hybrid DFT functional is used as a parameter. By varying this parameter, a set of different but related functionals are obtained. The various functionals are applied to one of the reactions occurring in the enzyme family heme-copper oxidases, the reduction of nitric oxide (NO) to nitrous oxide (N2O) and water. The results show that, even though certain parts of the calculated energetics exhibit large variations, the qualitative pictures of the reaction mechanisms are quite stable. Furthermore, it is found that the functional with 15% exact exchange (B3LYP*) gives the best agreement with experimental data for the particular reactions studied. An important aspect of the procedure used is that the computational results are carefully combined with a few more general experimental data to obtain a complete description of the entire catalytic cycle of the reactions studied.
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Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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9
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Wang J, Wang X, Ouyang Q, Liu W, Shan J, Tan H, Li X, Chen G. N-Nitrosation Mechanism Catalyzed by Non-heme Iron-Containing Enzyme SznF Involving Intramolecular Oxidative Rearrangement. Inorg Chem 2021; 60:7719-7731. [PMID: 34004115 DOI: 10.1021/acs.inorgchem.1c00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The non-heme iron-dependent enzyme SznF catalyzes a critical N-nitrosation step during the N-nitrosourea pharmacophore biosynthesis in streptozotocin. The intramolecular oxidative rearrangement process is known to proceed at the FeII-containing active site in the cupin domain of SznF, but its mechanism has not been elucidated to date. In this study, based on the density functional theory calculations, a unique mechanism was proposed for the N-nitrosation reaction catalyzed by SznF in which a four-electron oxidation process is accomplished through a series of complicated electron transferring between the iron center and substrate to bypass the high-valent FeIV═O species. In the catalytic reaction pathway, the O2 binds to the iron center and attacks on the substrate to form the peroxo bridge intermediate by obtaining two electrons from the substrate exclusively. Then, instead of cleaving the peroxo bridge, the Cε-Nω bond of the substrate is homolytically cleaved first to form a carbocation intermediate, which polarizes the peroxo bridge and promotes its heterolysis. After O-O bond cleavage, the following reaction steps proceed effortlessly so that the N-nitrosation is accomplished without NO exchange among reaction species.
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Affiliation(s)
- Junkai Wang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xixi Wang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Qingwen Ouyang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jiankai Shan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Hongwei Tan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xichen Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Guangju Chen
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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10
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Wei WM, Xu YL, Zheng RH, Zhao T, Fang W, Qin YD. Theoretical Study on the Mechanism of the Acylate Reaction of β-Lactamase. ACS OMEGA 2021; 6:12598-12604. [PMID: 34056410 PMCID: PMC8154126 DOI: 10.1021/acsomega.1c00592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/26/2021] [Indexed: 05/25/2023]
Abstract
Using density functional theory and a cluster approach, we study the reaction potential surface and compute Gibbs free energies for the acylate reaction of β-lactamase with penicillin G, where the solvent effect is important and taken into consideration. Two reaction paths are investigated: one is a multi-step process with a rate-limit energy barrier of 19.1 kcal/mol, which is relatively small, and the reaction can easily occur; the other is a one-step process with a barrier of 45.0 kcal/mol, which is large and thus makes the reaction hard to occur. The reason why the two paths have different barriers is explained.
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Affiliation(s)
- Wen-Mei Wei
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Yan-Li Xu
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Ren-Hui Zheng
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, Institute of
Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, P. R. China
| | - Tingting Zhao
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Weijun Fang
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Yi-De Qin
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
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11
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Blomberg MRA. Activation of O 2 and NO in heme-copper oxidases - mechanistic insights from computational modelling. Chem Soc Rev 2021; 49:7301-7330. [PMID: 33006348 DOI: 10.1039/d0cs00877j] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Heme-copper oxidases are transmembrane enzymes involved in aerobic and anaerobic respiration. The largest subgroup contains the cytochrome c oxidases (CcO), which reduce molecular oxygen to water. A significant part of the free energy released in this exergonic process is conserved as an electrochemical gradient across the membrane, via two processes, electrogenic chemistry and proton pumping. A deviant subgroup is the cytochrome c dependent NO reductases (cNOR), which reduce nitric oxide to nitrous oxide and water. This is also an exergonic reaction, but in this case none of the released free energy is conserved. Computational studies applying hybrid density functional theory to cluster models of the bimetallic active sites in the heme-copper oxidases are reviewed. To obtain a reliable description of the reaction mechanisms, energy profiles of the entire catalytic cycles, including the reduction steps have to be constructed. This requires a careful combination of computational results with certain experimental data. Computational studies have elucidated mechanistic details of the chemical parts of the reactions, involving cleavage and formation of covalent bonds, which have not been obtainable from pure experimental investigations. Important insights regarding the mechanisms of energy conservation have also been gained. The computational studies show that the reduction potentials of the active site cofactors in the CcOs are large enough to afford electrogenic chemistry and proton pumping, i.e. efficient energy conservation. These results solve a conflict between different types of experimental data. A mechanism for the proton pumping, involving a specific and crucial role for the active site tyrosine, conserved in all CcOs, is suggested. For the cNORs, the calculations show that the low reduction potentials of the active site cofactors are optimized for fast elimination of the toxic NO molecules. At the same time, the low reduction potentials lead to endergonic reduction steps with high barriers. To prevent even higher barriers, which would lead to a too slow reaction, when the electrochemical gradient across the membrane is present, the chemistry must occur in a non-electrogenic manner. This explains why there is no energy conservation in cNOR.
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Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden.
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12
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Reed CJ, Lam QN, Mirts EN, Lu Y. Molecular understanding of heteronuclear active sites in heme-copper oxidases, nitric oxide reductases, and sulfite reductases through biomimetic modelling. Chem Soc Rev 2021; 50:2486-2539. [PMID: 33475096 PMCID: PMC7920998 DOI: 10.1039/d0cs01297a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Heme-copper oxidases (HCO), nitric oxide reductases (NOR), and sulfite reductases (SiR) catalyze the multi-electron and multi-proton reductions of O2, NO, and SO32-, respectively. Each of these reactions is important to drive cellular energy production through respiratory metabolism and HCO, NOR, and SiR evolved to contain heteronuclear active sites containing heme/copper, heme/nonheme iron, and heme-[4Fe-4S] centers, respectively. The complexity of the structures and reactions of these native enzymes, along with their large sizes and/or membrane associations, make it challenging to fully understand the crucial structural features responsible for the catalytic properties of these active sites. In this review, we summarize progress that has been made to better understand these heteronuclear metalloenzymes at the molecular level though study of the native enzymes along with insights gained from biomimetic models comprising either small molecules or proteins. Further understanding the reaction selectivity of these enzymes is discussed through comparisons of their similar heteronuclear active sites, and we offer outlook for further investigations.
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Affiliation(s)
- Christopher J Reed
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA.
| | - Quan N Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA
| | - Evan N Mirts
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA. and Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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13
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Tosha T, Yamagiwa R, Sawai H, Shiro Y. NO Dynamics in Microbial Denitrification System. CHEM LETT 2021. [DOI: 10.1246/cl.200629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Takehiko Tosha
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Raika Yamagiwa
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hitomi Sawai
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
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14
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Yu L, Harris E, Lewicka-Szczebak D, Barthel M, Blomberg MRA, Harris SJ, Johnson MS, Lehmann MF, Liisberg J, Müller C, Ostrom NE, Six J, Toyoda S, Yoshida N, Mohn J. What can we learn from N 2 O isotope data? - Analytics, processes and modelling. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8858. [PMID: 32548934 DOI: 10.1002/rcm.8858] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 05/21/2023]
Abstract
The isotopic composition of nitrous oxide (N2 O) provides useful information for evaluating N2 O sources and budgets. Due to the co-occurrence of multiple N2 O transformation pathways, it is, however, challenging to use isotopic information to quantify the contribution of distinct processes across variable spatiotemporal scales. Here, we present an overview of recent progress in N2 O isotopic studies and provide suggestions for future research, mainly focusing on: analytical techniques; production and consumption processes; and interpretation and modelling approaches. Comparing isotope-ratio mass spectrometry (IRMS) with laser absorption spectroscopy (LAS), we conclude that IRMS is a precise technique for laboratory analysis of N2 O isotopes, while LAS is more suitable for in situ/inline studies and offers advantages for site-specific analyses. When reviewing the link between the N2 O isotopic composition and underlying mechanisms/processes, we find that, at the molecular scale, the specific enzymes and mechanisms involved determine isotopic fractionation effects. In contrast, at plot-to-global scales, mixing of N2 O derived from different processes and their isotopic variability must be considered. We also find that dual isotope plots are effective for semi-quantitative attribution of co-occurring N2 O production and reduction processes. More recently, process-based N2 O isotopic models have been developed for natural abundance and 15 N-tracing studies, and have been shown to be effective, particularly for data with adequate temporal resolution. Despite the significant progress made over the last decade, there is still great need and potential for future work, including development of analytical techniques, reference materials and inter-laboratory comparisons, further exploration of N2 O formation and destruction mechanisms, more observations across scales, and design and validation of interpretation and modelling approaches. Synthesizing all these efforts, we are confident that the N2 O isotope community will continue to advance our understanding of N2 O transformation processes in all spheres of the Earth, and in turn to gain improved constraints on regional and global budgets.
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Affiliation(s)
- Longfei Yu
- Laboratory for Air Pollution & Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland
- Institute of Groundwater and Earth Sciences, Jinan University, Guangzhou, 510632, China
| | - Eliza Harris
- Department of Ecology, University of Innsbruck, Sternwartestrasse 15, Innsbruck, A-6020, Austria
| | - Dominika Lewicka-Szczebak
- Centre for Stable Isotope Research and Analysis (KOSI), Büsgen Institute, Georg-August University of Göttingen, Germany
| | - Matti Barthel
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, SE-10691, Sweden
| | - Stephen J Harris
- School of Biological, Earth and Environmental Sciences, UNSW, Sydney, NSW, Australia
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Matthew S Johnson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø, DK-2100, Denmark
| | - Moritz F Lehmann
- Department of Environmental Science, University of Basel, Basel, Switzerland
| | - Jesper Liisberg
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Christoph Müller
- Institute of Plant Ecology (IFZ), Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, Giessen, 35392, Germany
- School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Nathaniel E Ostrom
- Department of Integrative Biology and DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
| | - Johan Six
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, 226-8502, Japan
| | - Naohiro Yoshida
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, 226-8502, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Joachim Mohn
- Laboratory for Air Pollution & Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland
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15
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Blomberg MRA. Role of the Two Metals in the Active Sites of Heme Copper Oxidases-A Study of NO Reduction in cbb3 Cytochrome c Oxidase. Inorg Chem 2020; 59:11542-11553. [PMID: 32799475 DOI: 10.1021/acs.inorgchem.0c01351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The superfamily of heme copper oxidases reduces molecular oxygen or nitric oxide, and the active sites comprise a high-spin heme group (a3 or b3) and a non-heme metal (CuB or FeB). The cbb3 C family of cytochrome c oxidases, with the high-spin heme b3 and CuB in the active site, is a subfamily of the heme copper oxidases that can reduce both molecular oxygen, which is the main substrate, and nitric oxide. The mechanism for NO reduction in cbb3 oxidase is studied here using hybrid density functional theory and compared to other cytochrome c oxidases (A and B families), with a high-spin heme a3 and CuB in the active site, and to cytochrome c dependent NO reductase, with a high-spin heme b3 and a non-heme FeB in the active site. It is found that the reaction mechanism and the detailed reaction energetics of the cbb3 oxidases are not similar to those of cytochrome c dependent NO reductase, which has the same type of high-spin heme group but a different non-heme metal. This is in contrast to earlier expectations. Instead, the NO reduction mechanism in cbb3 oxidases is very similar to that in the other cytochrome c oxidases, with the same non-heme metal, CuB, and is independent of the type of high-spin heme group. The conclusion is that the type of non-heme metal (CuB or FeB) in the active site of the heme copper oxidases is more important for the reaction mechanisms than the type of high-spin heme, at least for the NO reduction reaction. The reason is that the proton-coupled reduction potentials of the active site cofactors determine the energetics for the NO reduction reaction, and they depend to a larger extent on the non-heme metal. Observed differences in NO reduction reactivity among the various cytochrome c oxidases may be explained by differences outside the BNC, affecting the rate of proton transfer, rather than in the BNC itself.
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16
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Takeda H, Kimura T, Nomura T, Horitani M, Yokota A, Matsubayashi A, Ishii S, Shiro Y, Kubo M, Tosha T. Timing of NO Binding and Protonation in the Catalytic Reaction of Bacterial Nitric Oxide Reductase as Established by Time-Resolved Spectroscopy. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Hanae Takeda
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
| | - Tetsunari Kimura
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Takashi Nomura
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
| | - Masaki Horitani
- Department of Applied Biochemistry & Food Science, Saga University, Saga 840-8502, Japan
| | - Azusa Yokota
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Akiko Matsubayashi
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Shoko Ishii
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
| | - Takehiko Tosha
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
- RIKEN SPring-8 Center, Hyogo 679-5148, Japan
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17
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Ferousi C, Majer SH, DiMucci IM, Lancaster KM. Biological and Bioinspired Inorganic N-N Bond-Forming Reactions. Chem Rev 2020; 120:5252-5307. [PMID: 32108471 PMCID: PMC7339862 DOI: 10.1021/acs.chemrev.9b00629] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The metallobiochemistry underlying the formation of the inorganic N-N-bond-containing molecules nitrous oxide (N2O), dinitrogen (N2), and hydrazine (N2H4) is essential to the lifestyles of diverse organisms. Similar reactions hold promise as means to use N-based fuels as alternative carbon-free energy sources. This review discusses research efforts to understand the mechanisms underlying biological N-N bond formation in primary metabolism and how the associated reactions are tied to energy transduction and organismal survival. These efforts comprise studies of both natural and engineered metalloenzymes as well as synthetic model complexes.
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Affiliation(s)
- Christina Ferousi
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Sean H Majer
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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18
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Sheng X, Kazemi M, Planas F, Himo F. Modeling Enzymatic Enantioselectivity using Quantum Chemical Methodology. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00983] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xiang Sheng
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
| | - Masoud Kazemi
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
| | - Ferran Planas
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
| | - Fahmi Himo
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
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19
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Abucayon EG, Khade RL, Powell DR, Zhang Y, Richter-Addo GB. Not Limited to Iron: A Cobalt Heme-NO Model Facilitates N-N Coupling with External NO in the Presence of a Lewis Acid to Generate N 2 O. Angew Chem Int Ed Engl 2019; 58:18598-18603. [PMID: 31591802 DOI: 10.1002/anie.201909137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/17/2019] [Indexed: 01/15/2023]
Abstract
Some bacterial heme proteins catalyze the coupling of two NO molecules to generate N2 O. We previously reported that a heme Fe-NO model engages in this N-N bond-forming reaction with NO. We now demonstrate that (OEP)CoII (NO) similarly reacts with 1 equiv of NO in the presence of the Lewis acids BX3 (X=F, C6 F5 ) to generate N2 O. DFT calculations support retention of the CoII oxidation state for the experimentally observed adduct (OEP)CoII (NO⋅BF3 ), the presumed hyponitrite intermediate (P.+ )CoII (ONNO⋅BF3 ), and the porphyrin π-radical cation by-product of this reaction, and that the π-radical cation formation likely occurs at the hyponitrite stage. In contrast, the Fe analogue undergoes a ferrous-to-ferric oxidation state conversion during this reaction. Our work shows that cobalt hemes are chemically competent to engage in the NO-to-N2 O conversion reaction.
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Affiliation(s)
- Erwin G Abucayon
- Price Family Foundation of Structural Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ, 07030, USA
| | - Douglas R Powell
- Price Family Foundation of Structural Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ, 07030, USA
| | - George B Richter-Addo
- Price Family Foundation of Structural Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA
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20
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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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21
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Abucayon EG, Khade RL, Powell DR, Zhang Y, Richter‐Addo GB. Not Limited to Iron: A Cobalt Heme–NO Model Facilitates N–N Coupling with External NO in the Presence of a Lewis Acid to Generate N
2
O. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Erwin G. Abucayon
- Price Family Foundation of Structural Biology Department of Chemistry and Biochemistry University of Oklahoma Norman OK 73019 USA
| | - Rahul L. Khade
- Department of Chemistry and Chemical Biology Stevens Institute of Technology Castle Point on Hudson Hoboken NJ 07030 USA
| | - Douglas R. Powell
- Price Family Foundation of Structural Biology Department of Chemistry and Biochemistry University of Oklahoma Norman OK 73019 USA
| | - Yong Zhang
- Department of Chemistry and Chemical Biology Stevens Institute of Technology Castle Point on Hudson Hoboken NJ 07030 USA
| | - George B. Richter‐Addo
- Price Family Foundation of Structural Biology Department of Chemistry and Biochemistry University of Oklahoma Norman OK 73019 USA
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22
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Lehnert N, Fujisawa K, Camarena S, Dong HT, White CJ. Activation of Non-Heme Iron-Nitrosyl Complexes: Turning Up the Heat. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03219] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Kiyoshi Fujisawa
- Department of Chemistry, Ibaraki University, Mito 310-8512, Japan
| | - Stephanie Camarena
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Hai T. Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Corey J. White
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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23
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Kahle M, Blomberg MRA, Jareck S, Ädelroth P. Insights into the mechanism of nitric oxide reductase from a Fe B -depleted variant. FEBS Lett 2019; 593:1351-1359. [PMID: 31077353 DOI: 10.1002/1873-3468.13436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/29/2019] [Accepted: 05/09/2019] [Indexed: 11/06/2022]
Abstract
A key step of denitrification, the reduction of toxic nitric oxide to nitrous oxide, is catalysed by cytochrome c-dependent NO reductase (cNOR). cNOR contains four redox-active cofactors: three hemes and a nonheme iron (FeB ). Heme b3 and FeB constitute the active site, but the specific mechanism of NO-binding events and reduction is under debate. Here, we used a recently constructed, fully folded and hemylated cNOR variant that lacks FeB to investigate the role of FeB during catalysis. We show that in the FeB -less cNOR, binding of both NO and O2 to heme b3 still occurs but further reduction is impaired, although to a lesser degree for O2 than for NO. Implications for the catalytic mechanisms of cNOR are discussed.
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Affiliation(s)
- Maximilian Kahle
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | | | - Sascha Jareck
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
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24
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Weitz AC, Giri N, Frederick RE, Kurtz DM, Bominaar EL, Hendrich MP. Spectroscopy and DFT Calculations of Flavo-Diiron Nitric Oxide Reductase Identify Bridging Structures of NO-Coordinated Diiron Intermediates. ACS Catal 2018; 8:11704-11715. [PMID: 31263628 PMCID: PMC6602092 DOI: 10.1021/acscatal.8b03051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Flavo-diiron proteins (FDPs) are widespread in anaerobic bacteria, archaea, and protozoa, where they serve as the terminal components of dioxygen and nitric oxide reductive scavenging pathways. FDPs contain an N,O-ligated diiron site adjacent to a flavin mononucleotide (FMN) cofactor. The diiron site is structurally similar to those in hemerythrin, ribonucleotide reductase, and methane monooxygenase. However, only FDPs turn over NO to N2O at significant rates and yields. Previous studies revealed sequential binding of two NO molecules to the diferrous site, forming mono- and dinitrosyl intermediates leading to N2O formation. In the present work, these mono- and dinitrosyl intermediates have been characterized by EPR and Mössbauer spectroscopies and DFT calculations. Our results show that the iron proximal to the cofactor binds the first NO to form the diiron mononitrosyl complex, implying the iron distal to the FMN binds the second NO to form the diiron dinitrosyl intermediate. The exchange-coupling constants, J (H = JS1·S2), were found to differ substantially, +17 cm-1 for the diiron mononitrosyl and +60 cm-1 for the diiron dinitrosyl. Notwithstanding this large difference, our findings indicate retention of at least one hydroxo bridge throughout the NOR catalytic cycle. The Mossbauer hyperfine parameters and DFT calculations confirmed a semibridging NO- ligand in the mononitrosyl intermediate that lowers the exchange parameter. The DFT calculations on the dinitrosyl intermediate suggest a contribution to J from direct exchange between the S = 1 spins on the NO- ligands, which could initiate N-N bond formation. Our results provide insight into why FDPs are the only known nonheme diiron enzymes that competently turn over NO to N2O.
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Affiliation(s)
- Andrew C. Weitz
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Nitai Giri
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Rosanne E. Frederick
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Donald M. Kurtz
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael P. Hendrich
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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25
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Sabuncu S, Reed JH, Lu Y, Moënne-Loccoz P. Nitric Oxide Reductase Activity in Heme-Nonheme Binuclear Engineered Myoglobins through a One-Electron Reduction Cycle. J Am Chem Soc 2018; 140:17389-17393. [PMID: 30512937 DOI: 10.1021/jacs.8b11037] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
FeBMbs are structural and functional models of native bacterial nitric oxide reductases (NORs) generated through engineering of myoglobin. These biosynthetic models replicate the heme-nonheme diiron site of NORs and allow substitutions of metal centers and heme cofactors. Here, we provide evidence for multiple NOR turnover in monoformyl-heme-containing FeBMb1 proteins loaded with FeII, CoII, or ZnII metal ions at the FeB site (FeII/CoII/ZnII-FeBMb1(MF-heme)). FTIR detection of the ν(NNO) band of N2O at 2231 cm-1 provides a direct quantitative measurement of the product in solution. A maximum number of turnover is observed with FeII-FeBMb1(MF-heme), but the NOR activity is retained when the FeB site is loaded with ZnII. These data support the viability of a one-electron semireduced pathway for the reduction of NO at binuclear centers in reducing conditions.
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Affiliation(s)
- Sinan Sabuncu
- Department of Biochemistry & Molecular Biology , Oregon Health & Science University , Portland , Oregon 97239 , United States
| | - Julian H Reed
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yi Lu
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Pierre Moënne-Loccoz
- Department of Biochemistry & Molecular Biology , Oregon Health & Science University , Portland , Oregon 97239 , United States
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26
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Beck D, Klüfers P. HN 2 O 2 - as a Ligand in Mononuclear Hydrogenhyponitrite-κ 2 -N,O Ruthenium Complexes with Bisphosphane Co-Ligands. Chemistry 2018; 24:16019-16028. [PMID: 30144196 DOI: 10.1002/chem.201803770] [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: 07/23/2018] [Indexed: 01/21/2023]
Abstract
The hyponitrite anion is a tentative intermediate in the reduction of nitric oxide (NO) to nitrous oxide (N2 O) catalyzed by nitric-oxide reductase (NOR) in the process of bacterial denitrification. Owing to the considerable number of known coordination modes for the hyponitrito ligand, its actual bonding form in the enzymatic cycle is a point of current discussion. Here, we contribute to the hardly known ligand properties of a key intermediate, the monoprotonated hyponitrite anion. Three air- and water-stable ruthenium complexes with hydrogenhyponitrite as the ligand were synthesized by using commercially available bisphosphane co-ligands (1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)ethene (dppv)). The starting compounds [Ru(dppe)2 (tos)]BF4 (1) and [Ru(dppp)2 (tos)]BF4 (2) contained the bidentate coordinating tosylate anion (tos) as a particularly well-suited leaving group. To confirm the protonated and deprotonated species, X-ray diffraction, IR, UV/Vis spectroscopy (solution and solid state), solid-state NMR spectroscopy, and high-resolution mass spectroscopy were used. DFT calculations give insight into the bonding situation. We report on [Ru(dppe)2 (HN2 O2 )]BF4 (5), [Ru(dppp)2 (HN2 O2 )]BF4 (6), [Ru(dppv)2 (HN2 O2 )]BF4 (7), [Ru(dppp)2 (HN2 O2 )]BF4 ⋅Imi (9; Imi=imidazole) as the first mononuclear trans-hydrogenhyponitrite complexes. Isolated deprotonated analogs are [Ru(dppe)2 (N2 O2 )]⋅HImi(BF4 ) (8) and [Ru(dppv)2 (N2 O2 )] ⋅HImi(BF4 )⋅Imi (10).
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Affiliation(s)
- Daniel Beck
- Ludwig-Maximilians-Universitaet, Department of Chemistry, Butenandtstrasse 5-13, Haus D, München, 81377, Germany
| | - Peter Klüfers
- Ludwig-Maximilians-Universitaet, Department of Chemistry, Butenandtstrasse 5-13, Haus D, München, 81377, Germany
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27
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28
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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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29
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Kato M, Nakagawa S, Tosha T, Shiro Y, Masuda Y, Nakata K, Yagi I. Surface-Enhanced Infrared Absorption Spectroscopy of Bacterial Nitric Oxide Reductase under Electrochemical Control Using a Vibrational Probe of Carbon Monoxide. J Phys Chem Lett 2018; 9:5196-5200. [PMID: 30141632 DOI: 10.1021/acs.jpclett.8b02581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nitric oxide reductases (NORs) reduce nitric oxide to nitrous oxide in the denitrification pathway of the global nitrogen cycle. NORs contain four iron cofactors and the NO reduction occurs at the heme b3/nonheme FeB binuclear active site. The determination of reduction potentials of the iron cofactors will help us elucidate the enzymatic reaction mechanism. However, previous reports on these potentials remain controversial. Herein, we performed electrochemical and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements of Pseudomonas aeruginosa NOR immobilized on gold electrodes. Cyclic voltammograms exhibited two reduction peaks at -0.11 and -0.44 V vs SHE, and a SEIRA spectrum using a vibrational probe of CO showed a characteristic band at 1972 cm-1 at -0.4 V vs SHE, which was assigned to νCO of heme b3-CO. Our results suggest that the reduction of heme b3 initiates the enzymatic NO reduction.
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Affiliation(s)
- Masaru Kato
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN) , National Institute for Materials Science (NIMS) , Tsukuba 305-0044 , Japan
| | | | - Takehiko Tosha
- RIKEN , SPring-8 Center , Kouto, Sayo , Hyogo 679-5148 , Japan
| | - Yoshitsugu Shiro
- Graduate School of Life Science , University of Hyogo , Hyogo 678-1297 , Japan
| | | | | | - Ichizo Yagi
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN) , National Institute for Materials Science (NIMS) , Tsukuba 305-0044 , Japan
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30
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Van Stappen C, Lehnert N. Mechanism of N–N Bond Formation by Transition Metal–Nitrosyl Complexes: Modeling Flavodiiron Nitric Oxide Reductases. Inorg Chem 2018; 57:4252-4269. [DOI: 10.1021/acs.inorgchem.7b02333] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Casey Van Stappen
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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31
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Abucayon EG, Khade RL, Powell DR, Zhang Y, Richter-Addo GB. Lewis Acid Activation of the Ferrous Heme-NO Fragment toward the N-N Coupling Reaction with NO To Generate N 2O. J Am Chem Soc 2018; 140:4204-4207. [PMID: 29502400 DOI: 10.1021/jacs.7b13681] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Bacterial NO reductase (bacNOR) enzymes utilize a heme/non-heme active site to couple two NO molecules to N2O. We show that BF3 coordination to the nitrosyl O-atom in (OEP)Fe(NO) activates it toward N-N bond formation with NO to generate N2O. 15N-isotopic labeling reveals a reversible nitrosyl exchange reaction and follow-up N-O bond cleavage in the N2O formation step. Other Lewis acids (B(C6F5)3 and K+) also promote the NO coupling reaction with (OEP)Fe(NO). These results, complemented by DFT calculations, provide experimental support for the cis: b3 pathway in bacNOR.
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Affiliation(s)
- Erwin G Abucayon
- Department of Chemistry and Biochemistry , University of Oklahoma , Norman , Oklahoma 73019 , United States
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology , Stevens Institute of Technology , Castle Point on Hudson , Hoboken , New Jersey 07030 , United States
| | - Douglas R Powell
- Department of Chemistry and Biochemistry , University of Oklahoma , Norman , Oklahoma 73019 , United States
| | - Yong Zhang
- Department of Chemistry and Chemical Biology , Stevens Institute of Technology , Castle Point on Hudson , Hoboken , New Jersey 07030 , United States
| | - George B Richter-Addo
- Department of Chemistry and Biochemistry , University of Oklahoma , Norman , Oklahoma 73019 , United States
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32
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Fukuda R, Sakai S, Takagi N, Matsui M, Ehara M, Hosokawa S, Tanaka T, Sakaki S. Mechanism of NO–CO reaction over highly dispersed cuprous oxide on γ-alumina catalyst using a metal–support interfacial site in the presence of oxygen: similarities to and differences from biological systems. Catal Sci Technol 2018. [DOI: 10.1039/c8cy00080h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The NO–CO reaction mechanism over the Cu/γ-Al2O3 catalyst was elucidated using DFT and a cluster model.
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Affiliation(s)
- Ryoichi Fukuda
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Shogo Sakai
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Nozomi Takagi
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Masafuyu Matsui
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Masahiro Ehara
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Saburo Hosokawa
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Tsunehiro Tanaka
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Shigeyoshi Sakaki
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
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33
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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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34
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Blomberg MRA, Ädelroth P. The mechanism for oxygen reduction in cytochrome c dependent nitric oxide reductase (cNOR) as obtained from a combination of theoretical and experimental results. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:884-894. [PMID: 28801051 DOI: 10.1016/j.bbabio.2017.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/29/2017] [Accepted: 08/05/2017] [Indexed: 11/30/2022]
Abstract
Bacterial NO-reductases (NOR) belong to the heme-copper oxidase (HCuO) superfamily, in which most members are O2-reducing, proton-pumping enzymes. This study is one in a series aiming to elucidate the reaction mechanisms of the HCuOs, including the mechanisms for cellular energy conservation. One approach towards this goal is to compare the mechanisms for the different types of HCuOs, cytochrome c oxidase (CcO) and NOR, reducing the two substrates O2 and NO. Specifically in this study, we describe the mechanism for oxygen reduction in cytochrome c dependent NOR (cNOR). Hybrid density functional calculations were performed on large cluster models of the cNOR binuclear active site. Our results are used, together with published experimental information, to construct a free energy profile for the entire catalytic cycle. Although the overall reaction is quite exergonic, we show that during the reduction of molecular oxygen in cNOR, two of the reduction steps are endergonic with high barriers for proton uptake, which is in contrast to oxygen reduction in CcO, where all reduction steps are exergonic. This difference between the two enzymes is suggested to be important for their differing capabilities for energy conservation. An additional result from this study is that at least three of the four reduction steps are initiated by proton transfer to the active site, which is in contrast to CcO, where electrons always arrive before the protons to the active site. The roles of the non-heme metal ion and the redox-active tyrosine in the active site are also discussed.
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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, Stockholm SE-106 91, Sweden
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Abstract
The quantum chemical cluster approach is a powerful method for investigating enzymatic reactions. Over the past two decades, a large number of highly diverse systems have been studied and a great wealth of mechanistic insight has been developed using this technique. This Perspective reviews the current status of the methodology. The latest technical developments are highlighted, and challenges are discussed. Some recent applications are presented to illustrate the capabilities and progress of this approach, and likely future directions are outlined.
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Affiliation(s)
- Fahmi Himo
- Arrhenius Laboratory, Department of Organic Chemistry, Stockholm University , SE-106 91 Stockholm, Sweden
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