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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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Takeda H, Shimba K, Horitani M, Kimura T, Nomura T, Kubo M, Shiro Y, Tosha T. Trapping of a Mononitrosyl Nonheme Intermediate of Nitric Oxide Reductase by Cryo-Photolysis of Caged Nitric Oxide. J Phys Chem B 2023; 127:846-854. [PMID: 36602896 DOI: 10.1021/acs.jpcb.2c05852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Characterization of short-lived reaction intermediates is essential for elucidating the mechanism of the reaction catalyzed by metalloenzymes. Here, we demonstrated that the photolysis of a caged compound under cryogenic temperature followed by thermal annealing is an invaluable technique for trapping of short-lived reaction intermediates of metalloenzymes through the study of membrane-integrated nitric oxide reductase (NOR) that catalyzes reductive coupling of two NO molecules to N2O at its heme/nonheme FeB binuclear center. Although NO produced by the photolysis of caged NO did not react with NOR under cryogenic temperature, annealing to ∼160 K allowed NO to diffuse and react with NOR, which was evident from the appearance of EPR signals assignable to the S = 3/2 state. This indicates that the nonheme FeB-NO species can be trapped as the intermediate. Time-resolved IR spectroscopy with the use of the photolysis of caged NO as a reaction trigger showed that the intermediate formed at 10 μs gave the NO stretching frequency at 1683 cm-1 typical of nonheme Fe-NO, confirming that the combination of the cryo-photolysis of caged NO and annealing enabled us to trap the reaction intermediate. Thus, the cryo-photolysis of the caged compound has great potential for the characterization of short-lived reaction intermediates.
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Affiliation(s)
- Hanae Takeda
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan.,RIKEN SPring-8 center, Sayo, Hyogo 679-5148, Japan
| | - Kanji Shimba
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan.,RIKEN SPring-8 center, Sayo, Hyogo 679-5148, Japan
| | - Masaki Horitani
- Department of Applied Biochemistry & Food Science, Saga University, Saga 840-8502, Japan.,The United Graduate School of Agricultural Science, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Tetsunari Kimura
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - Takashi Nomura
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Takehiko Tosha
- Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan.,RIKEN SPring-8 center, Sayo, Hyogo 679-5148, Japan
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3
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Dey A, Albert T, Kong RY, Macmillan SN, Moënne-Loccoz P, Lancaster KM, Goldberg DP. Direct Reduction of NO to N 2O by a Mononuclear Nonheme Thiolate Ligated Iron(II) Complex via Formation of a Metastable {FeNO} 7 Complex. Inorg Chem 2022; 61:14909-14917. [PMID: 36107151 PMCID: PMC9555345 DOI: 10.1021/acs.inorgchem.2c02383] [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: 11/30/2022]
Abstract
Addition of NO to a nonheme dithiolate-ligated iron(II) complex, FeII(Me3TACN)(S2SiMe2) (1), results in the generation of N2O. Low-temperature spectroscopic studies reveal a metastable six-coordinate {FeNO}7 intermediate (S = 3/2) that was trapped at -135 °C and was characterized by low-temperature UV-vis, resonance Raman, EPR, Mössbauer, XAS, and DFT studies. Thermal decay of the {FeNO}7 species leads to the evolution of N2O, providing a rare example of a mononuclear thiolate-ligated {FeNO}7 that mediates NO reduction to N2O without the requirement of any exogenous electron or proton sources.
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Affiliation(s)
- Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218, United States
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, Unites States
| | - Richard Y. Kong
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, Unites States
| | - Samantha N. Macmillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, Unites States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, Unites States
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, Unites States
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218, United States
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4
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Albert T, Moënne-Loccoz P. Spectroscopic Characterization of a Diferric Mycobacterial Hemerythrin-Like Protein with Unprecedented Reactivity toward Nitric Oxide. J Am Chem Soc 2022; 144:17611-17621. [PMID: 36099449 DOI: 10.1021/jacs.2c07113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hemerythrin-like proteins (HLPs) are broadly distributed across taxonomic groups and appear to play highly diverse functional roles in prokaryotes. Mycobacterial HLPs contribute to the survival of these pathogenic bacteria in mammalian macrophages, but their modes of action remain unclear. A recent crystallographic characterization of Mycobacterium kansasii HLP (Mka-HLP) revealed the unexpected presence of a tyrosine sidechain (Tyr54) near the coordination sphere of one of the two iron centers. Here, we show that Tyr54 is a true ligand to the Fe2(III) ion which, in conjunction with the presence of a μ-oxo group bridging the two iron(III), brings unique reactivity toward nitric oxide (NO). Monitoring the titration of Mka-HLP with NO by Fourier-transform infrared and electron paramagnetic resonance spectroscopies shows that both diferric and diferrous forms of Mka-HLP accumulate an uncoupled high-spin and low-spin {FeNO}7 pair. We assign the reactivity of the diferric protein to an initial radical reaction between NO and the μ-oxo bridge to form nitrite and a mixed-valent diiron center that can react further with NO. Amperometric measurements of NO consumption by Mka-HLP confirm that this reactivity can proceed at low micromolar concentrations of NO, before additional NO consumption, supporting a NO scavenging role for mycobacterial HLPs.
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Affiliation(s)
- Therese Albert
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
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5
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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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6
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Stredansky M, Moro S, Corva M, Sturmeit H, Mischke V, Janas D, Cojocariu I, Jugovac M, Cossaro A, Verdini A, Floreano L, Feng Z, Sala A, Comelli G, Windischbacher A, Puschnig P, Hohner C, Kettner M, Libuda J, Cinchetti M, Schneider CM, Feyer V, Vesselli E, Zamborlini G. Disproportionation of Nitric Oxide at a Surface‐Bound Nickel Porphyrinoid. Angew Chem Int Ed Engl 2022; 61:e202201916. [PMID: 35267236 PMCID: PMC9314816 DOI: 10.1002/anie.202201916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Indexed: 11/28/2022]
Abstract
Uncommon metal oxidation states in porphyrinoid cofactors are responsible for the activity of many enzymes. The F430 and P450nor co‐factors, with their reduced NiI‐ and FeIII‐containing tetrapyrrolic cores, are prototypical examples of biological systems involved in methane formation and in the reduction of nitric oxide, respectively. Herein, using a comprehensive range of experimental and theoretical methods, we raise evidence that nickel tetraphenyl porphyrins deposited in vacuo on a copper surface are reactive towards nitric oxide disproportionation at room temperature. The interpretation of the measurements is far from being straightforward due to the high reactivity of the different nitrogen oxides species (eventually present in the residual gas background) and of the possible reaction intermediates. The picture is detailed in order to disentangle the challenging complexity of the system, where even a small fraction of contamination can change the scenario.
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Affiliation(s)
- Matus Stredansky
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Stefania Moro
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
| | - Manuel Corva
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | | | | | - David Janas
- Department of Physics TU Dortmund University Dortmund Germany
| | - Iulia Cojocariu
- Peter Grünberg Institute (PGI-6) Forschungszentrum Jülich GmbH Jülich Germany
| | - Matteo Jugovac
- Peter Grünberg Institute (PGI-6) Forschungszentrum Jülich GmbH Jülich Germany
| | - Albano Cossaro
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
- Department of Chemistry and Pharmaceutical Science University of Trieste via L-Giorgieri 1 34127 Trieste Italy
| | - Alberto Verdini
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Luca Floreano
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Zhijing Feng
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Alessandro Sala
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Giovanni Comelli
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | | | - Peter Puschnig
- Institut für Physik Karl-Franzens-Universität Graz 8010 Graz Austria
| | - Chantal Hohner
- Erlangen Center for Interface Research and Catalysis Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Miroslav Kettner
- Erlangen Center for Interface Research and Catalysis Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Jörg Libuda
- Erlangen Center for Interface Research and Catalysis Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Mirko Cinchetti
- Department of Physics TU Dortmund University Dortmund Germany
| | - Claus Michael Schneider
- Peter Grünberg Institute (PGI-6) Forschungszentrum Jülich GmbH Jülich Germany
- Fakultät f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE) Universität Duisburg-Essen 47048 Duisburg Germany
| | - Vitaliy Feyer
- Peter Grünberg Institute (PGI-6) Forschungszentrum Jülich GmbH Jülich Germany
- Fakultät f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE) Universität Duisburg-Essen 47048 Duisburg Germany
| | - Erik Vesselli
- Physics Department University of Trieste via A. Valerio 2 34127 Trieste Italy
- CNR-IOM, Area Science Park S.S. 14 km 163,5 34149 Trieste Italy
| | - Giovanni Zamborlini
- Department of Physics TU Dortmund University Dortmund Germany
- Peter Grünberg Institute (PGI-6) Forschungszentrum Jülich GmbH Jülich Germany
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7
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Stredansky M, Moro S, Corva M, Sturmeit H, Mischke V, Janas D, Cojocariu I, Jugovac M, Cossaro A, Verdini A, Floreano L, Feng Z, Sala A, Comelli G, Windischbacher A, Puschnig P, Hohner C, Kettner M, Libuda J, Cinchetti M, Schneider CM, Feyer V, Vesselli E, Zamborlini G. Disproportionation of Nitric Oxide at a Surface-Bound Nickel Porphyrinoid. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 134:e202201916. [PMID: 38505699 PMCID: PMC10947138 DOI: 10.1002/ange.202201916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Indexed: 11/07/2022]
Abstract
Uncommon metal oxidation states in porphyrinoid cofactors are responsible for the activity of many enzymes. The F430 and P450nor co-factors, with their reduced NiI- and FeIII-containing tetrapyrrolic cores, are prototypical examples of biological systems involved in methane formation and in the reduction of nitric oxide, respectively. Herein, using a comprehensive range of experimental and theoretical methods, we raise evidence that nickel tetraphenyl porphyrins deposited in vacuo on a copper surface are reactive towards nitric oxide disproportionation at room temperature. The interpretation of the measurements is far from being straightforward due to the high reactivity of the different nitrogen oxides species (eventually present in the residual gas background) and of the possible reaction intermediates. The picture is detailed in order to disentangle the challenging complexity of the system, where even a small fraction of contamination can change the scenario.
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Affiliation(s)
- Matus Stredansky
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | - Stefania Moro
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
| | - Manuel Corva
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | | | | | - David Janas
- Department of PhysicsTU Dortmund UniversityDortmundGermany
| | - Iulia Cojocariu
- Peter Grünberg Institute (PGI-6)Forschungszentrum Jülich GmbHJülichGermany
| | - Matteo Jugovac
- Peter Grünberg Institute (PGI-6)Forschungszentrum Jülich GmbHJülichGermany
| | - Albano Cossaro
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
- Department of Chemistry and Pharmaceutical ScienceUniversity of Triestevia L-Giorgieri 134127TriesteItaly
| | | | - Luca Floreano
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | - Zhijing Feng
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | | | - Giovanni Comelli
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | | | - Peter Puschnig
- Institut für PhysikKarl-Franzens-Universität Graz8010GrazAustria
| | - Chantal Hohner
- Erlangen Center for Interface Research and CatalysisFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Miroslav Kettner
- Erlangen Center for Interface Research and CatalysisFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Jörg Libuda
- Erlangen Center for Interface Research and CatalysisFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | | | - Claus Michael Schneider
- Peter Grünberg Institute (PGI-6)Forschungszentrum Jülich GmbHJülichGermany
- Fakultät f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE)Universität Duisburg-Essen47048DuisburgGermany
| | - Vitaliy Feyer
- Peter Grünberg Institute (PGI-6)Forschungszentrum Jülich GmbHJülichGermany
- Fakultät f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE)Universität Duisburg-Essen47048DuisburgGermany
| | - Erik Vesselli
- Physics DepartmentUniversity of Triestevia A. Valerio 234127TriesteItaly
- CNR-IOM, Area Science ParkS.S. 14 km 163,534149TriesteItaly
| | - Giovanni Zamborlini
- Department of PhysicsTU Dortmund UniversityDortmundGermany
- Peter Grünberg Institute (PGI-6)Forschungszentrum Jülich GmbHJülichGermany
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8
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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: 92] [Impact Index Per Article: 30.7] [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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9
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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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10
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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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11
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DiPrimio DJ, Holland PL. Repurposing metalloproteins as mimics of natural metalloenzymes for small-molecule activation. J Inorg Biochem 2021; 219:111430. [PMID: 33873051 DOI: 10.1016/j.jinorgbio.2021.111430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022]
Abstract
Artificial metalloenzymes (ArMs) consist of an unnatural metal or cofactor embedded in a protein scaffold, and are an excellent platform for applying the concepts of protein engineering to catalysis. In this Focused Review, we describe the application of ArMs as simple, tunable artificial models of the active sites of complex natural metalloenzymes for small-molecule activation. In this sense, ArMs expand the strategies of synthetic model chemistry to protein-based supporting ligands with potential for participation from the second coordination sphere. We focus specifically on ArMs that are structural, spectroscopic, and functional models of enzymes for activation of small molecules like CO, CO2, O2, N2, and NO, as well as production/consumption of H2. These ArMs give insight into the identities and roles of metalloenzyme structural features within and near the cofactor. We give examples of ArM work relevant to hydrogenases, acetyl-coenzyme A synthase, superoxide dismutase, heme oxygenases, nitric oxide reductase, methyl-coenzyme M reductase, copper-O2 enzymes, and nitrogenases.
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Affiliation(s)
- Daniel J DiPrimio
- Department of Chemistry, Yale University, New Haven, CT, 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, CT, 06520, United States.
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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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Klein AS, Zeymer C. Design and engineering of artificial metalloproteins: from de novo metal coordination to catalysis. Protein Eng Des Sel 2021; 34:6150309. [PMID: 33635315 DOI: 10.1093/protein/gzab003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 11/13/2022] Open
Abstract
Metalloproteins are essential to sustain life. Natural evolution optimized them for intricate structural, regulatory and catalytic functions that cannot be fulfilled by either a protein or a metal ion alone. In order to understand this synergy and the complex design principles behind the natural systems, simpler mimics were engineered from the bottom up by installing de novo metal sites in either natural or fully designed, artificial protein scaffolds. This review focuses on key challenges associated with this approach. We discuss how proteins can be equipped with binding sites that provide an optimal coordination environment for a metal cofactor of choice, which can be a single metal ion or a complex multinuclear cluster. Furthermore, we highlight recent studies in which artificial metalloproteins were engineered towards new functions, including electron transfer and catalysis. In this context, the powerful combination of de novo protein design and directed evolution is emphasized for metalloenzyme development.
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Affiliation(s)
- Andreas S Klein
- Department of Chemistry, Technische Universität München, 85747 Garching, Germany
| | - Cathleen Zeymer
- Department of Chemistry, Technische Universität München, 85747 Garching, Germany
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14
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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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15
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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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16
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Caranto JD. The emergence of nitric oxide in the biosynthesis of bacterial natural products. Curr Opin Chem Biol 2019; 49:130-138. [DOI: 10.1016/j.cbpa.2018.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/28/2018] [Accepted: 11/09/2018] [Indexed: 12/16/2022]
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17
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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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18
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Adam SM, Wijeratne GB, Rogler PJ, Diaz DE, Quist DA, Liu JJ, Karlin KD. Synthetic Fe/Cu Complexes: Toward Understanding Heme-Copper Oxidase Structure and Function. Chem Rev 2018; 118:10840-11022. [PMID: 30372042 PMCID: PMC6360144 DOI: 10.1021/acs.chemrev.8b00074] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heme-copper oxidases (HCOs) are terminal enzymes on the mitochondrial or bacterial respiratory electron transport chain, which utilize a unique heterobinuclear active site to catalyze the 4H+/4e- reduction of dioxygen to water. This process involves a proton-coupled electron transfer (PCET) from a tyrosine (phenolic) residue and additional redox events coupled to transmembrane proton pumping and ATP synthesis. Given that HCOs are large, complex, membrane-bound enzymes, bioinspired synthetic model chemistry is a promising approach to better understand heme-Cu-mediated dioxygen reduction, including the details of proton and electron movements. This review encompasses important aspects of heme-O2 and copper-O2 (bio)chemistries as they relate to the design and interpretation of small molecule model systems and provides perspectives from fundamental coordination chemistry, which can be applied to the understanding of HCO activity. We focus on recent advancements from studies of heme-Cu models, evaluating experimental and computational results, which highlight important fundamental structure-function relationships. Finally, we provide an outlook for future potential contributions from synthetic inorganic chemistry and discuss their implications with relevance to biological O2-reduction.
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Affiliation(s)
- Suzanne M. Adam
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gayan B. Wijeratne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Patrick J. Rogler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Daniel E. Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeffrey J. Liu
- 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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19
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20
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Heme redox potentials hold the key to reactivity differences between nitric oxide reductase and heme-copper oxidase. Proc Natl Acad Sci U S A 2018; 115:6195-6200. [PMID: 29802230 DOI: 10.1073/pnas.1720298115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite high structural homology between NO reductases (NORs) and heme-copper oxidases (HCOs), factors governing their reaction specificity remain to be understood. Using a myoglobin-based model of NOR (FeBMb) and tuning its heme redox potentials (E°') to cover the native NOR range, through manipulating hydrogen bonding to the proximal histidine ligand and replacing heme b with monoformyl (MF-) or diformyl (DF-) hemes, we herein demonstrate that the E°' holds the key to reactivity differences between NOR and HCO. Detailed electrochemical, kinetic, and vibrational spectroscopic studies, in tandem with density functional theory calculations, demonstrate a strong influence of heme E°' on NO reduction. Decreasing E°' from +148 to -130 mV significantly impacts electronic properties of the NOR mimics, resulting in 180- and 633-fold enhancements in NO association and heme-nitrosyl decay rates, respectively. Our results indicate that NORs exhibit finely tuned E°' that maximizes their enzymatic efficiency and helps achieve a balance between opposite factors: fast NO binding and decay of dinitrosyl species facilitated by low E°' and fast electron transfer facilitated by high E°'. Only when E°' is optimally tuned in FeBMb(MF-heme) for NO binding, heme-nitrosyl decay, and electron transfer does the protein achieve multiple (>35) turnovers, previously not achieved by synthetic or enzyme-based NOR models. This also explains a long-standing question in bioenergetics of selective cross-reactivity in HCOs. Only HCOs with heme E°' in a similar range as NORs (between -59 and 200 mV) exhibit NOR reactivity. Thus, our work demonstrates efficient tuning of E°' in various metalloproteins for their optimal functionality.
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21
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Vilbert AC, Caranto JD, Lancaster KM. Influences of the heme-lysine crosslink in cytochrome P460 over redox catalysis and nitric oxide sensitivity. Chem Sci 2017; 9:368-379. [PMID: 29629106 PMCID: PMC5872139 DOI: 10.1039/c7sc03450d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/31/2017] [Indexed: 11/21/2022] Open
Abstract
Ammonia (NH3)-oxidizing bacteria (AOB) derive total energy for life from the multi-electron oxidation of NH3 to nitrite (NO2-). One obligate intermediate of this metabolism is hydroxylamine (NH2OH), which can be oxidized to the potent greenhouse agent nitrous oxide (N2O) by the AOB enzyme cytochrome (cyt) P460. We have now spectroscopically characterized a 6-coordinate (6c) {FeNO}7 intermediate on the NH2OH oxidation pathway of cyt P460. This species has two fates: it can either be oxidized to the {FeNO}6 that then undergoes attack by NH2OH to ultimately generate N2O, or it can lose its axial His ligand, thus generating a stable, off-pathway 5-coordinate (5c) {FeNO}7 species. We show that the wild type (WT) cyt P460 exhibits a slow nitric oxide (NO)-independent conversion (kHis-off = 2.90 × 10-3 s-1), whereas a cross-link-deficient Lys70Tyr cyt P460 mutant protein underwent His dissociation via both a NO-independent (kHis-off = 3.8 × 10-4 s-1) and a NO-dependent pathway [kHis-off(NO) = 790 M-1 s-1]. Eyring analyses of the NO-independent pathways for these two proteins revealed a significantly larger (ca. 27 cal mol-1 K-1) activation entropy (ΔS‡) in the cross-link-deficient mutant. Our results suggest that the Lys-heme cross-link confers rigidity to the positioning of the heme P460 cofactor to avoid the fast NO-dependent His dissociation pathway and subsequent formation of the off-pathway 5c {FeNO}7 species. The relevance of these findings to NO signaling proteins such as heme-nitric oxide/oxygen binding (H-NOX) is also discussed.
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Affiliation(s)
- Avery C Vilbert
- Department of Chemistry and Chemical Biology , Baker Laboratory , Cornell University , Ithaca , NY 14853 , USA .
| | - Jonathan D Caranto
- Department of Chemistry and Chemical Biology , Baker Laboratory , Cornell University , Ithaca , NY 14853 , USA .
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology , Baker Laboratory , Cornell University , Ithaca , NY 14853 , USA .
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22
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Harcourt RD. Construction of valence bond structures for {FeNO} 7 nitrosyl heme and non-heme complexes. Nitric Oxide 2017; 69:51-55. [PMID: 28478280 DOI: 10.1016/j.niox.2017.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/30/2017] [Indexed: 02/05/2023]
Abstract
For {FeNO}7 nitrosyl heme and non-heme complexes, with 17 valence shell electrons, FeIINO, FeIINO* and FeIIINO- valence bond structures of the increased-valence type are generated primarily from Lewis valence bond structures by delocalizing non-bonding electrons into diatomic bonding molecular orbitals. Valence bond formulations for the reactions 2MbNO + 2H+ → 2metMb + N2O + H2O and cis MbNO + NO- + 2H+ → metMb + N2O + H2O are also presented.
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Affiliation(s)
- Richard D Harcourt
- School of Chemistry, The University of Melbourne, Victoria 3010 Australia.
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23
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Suzuki T, Hemmi S, Kazama Y, Oyama D, Nagao H. Formation of Doubly Nitrosyl-Bridged Diruthenium Complex Bearing Tridentate Ethylbis(2-pyridylethyl)amine via Conversion of Nitrate. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2017. [DOI: 10.1246/bcsj.20170155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tomoyo Suzuki
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554
| | - Shohei Hemmi
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554
| | - Yuka Kazama
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554
| | - Dai Oyama
- Cluster of Science and Engineering, Fukushima University, 1 Kanayagawa, Fukushima 960-1296
| | - Hirotaka Nagao
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554
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24
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Reed JH, Shi Y, Zhu Q, Chakraborty S, Mirts EN, Petrik ID, Bhagi-Damodaran A, Ross M, Moënne-Loccoz P, Zhang Y, Lu Y. Manganese and Cobalt in the Nonheme-Metal-Binding Site of a Biosynthetic Model of Heme-Copper Oxidase Superfamily Confer Oxidase Activity through Redox-Inactive Mechanism. J Am Chem Soc 2017; 139:12209-12218. [PMID: 28768416 PMCID: PMC5673108 DOI: 10.1021/jacs.7b05800] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The presence of a nonheme metal, such as copper and iron, in the heme-copper oxidase (HCO) superfamily is critical to the enzymatic activity of reducing O2 to H2O, but the exact mechanism the nonheme metal ion uses to confer and fine-tune the activity remains to be understood. We herein report that manganese and cobalt can bind to the same nonheme site and confer HCO activity in a heme-nonheme biosynthetic model in myoglobin. While the initial rates of O2 reduction by the Mn, Fe, and Co derivatives are similar, the percentages of reactive oxygen species (ROS) formation are 7%, 4%, and 1% and the total turnovers are 5.1 ± 1.1, 13.4 ± 0.7, and 82.5 ± 2.5, respectively. These results correlate with the trends of nonheme-metal-binding dissociation constants (35, 22, and 9 μM) closely, suggesting that tighter metal binding can prevent ROS release from the active site, lessen damage to the protein, and produce higher total turnover numbers. Detailed spectroscopic, electrochemical, and computational studies found no evidence of redox cycling of manganese or cobalt in the enzymatic reactions and suggest that structural and electronic effects related to the presence of different nonheme metals lead to the observed differences in reactivity. This study of the roles of nonheme metal ions beyond the Cu and Fe found in native enzymes has provided deeper insights into nature's choice of metal ion and reaction mechanism and allows for finer control of the enzymatic activity, which is a basis for the design of efficient catalysts for the oxygen reduction reaction in fuel cells.
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Affiliation(s)
- Julian H. Reed
- Department of Biochemistry, University of Illinois at
Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yelu Shi
- Department of Biomedical Engineering, Chemistry, and Biological
Sciences, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Qianhong Zhu
- Division of Environmental & Biomolecular Systems, Institute
of Environmental Health, Oregon Health & Science University, Portland, OR,
97239, USA
| | - Saumen Chakraborty
- Department of Chemistry & Biochemistry, University of
Mississippi, Oxford, Mississippi, 38677, USA
| | - Evan N. Mirts
- Center for Biophysics and Quantitative Biology, University of
Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Igor D. Petrik
- Department of Chemistry, University of Illinois at Urbana-Champaign,
Urbana, IL, 61801, USA
| | - Ambika Bhagi-Damodaran
- Department of Pharmaceutical Chemistry, University of California,
San Francisco, San Francisco, CA, 94143, USA
| | - Matthew Ross
- Department of Chemistry, Northwestern University, Evanston, IL,
60208, USA
| | - Pierre Moënne-Loccoz
- Division of Environmental & Biomolecular Systems, Institute
of Environmental Health, Oregon Health & Science University, Portland, OR,
97239, USA
| | - Yong Zhang
- Department of Biomedical Engineering, Chemistry, and Biological
Sciences, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Yi Lu
- Department of Biochemistry, University of Illinois at
Urbana-Champaign, Urbana, IL, 61801, USA
- Center for Biophysics and Quantitative Biology, University of
Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign,
Urbana, IL, 61801, USA
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25
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26
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Rahman MH, Ryan MD. Redox and Spectroscopic Properties of Iron Porphyrin Nitroxyl in the Presence of Weak Acids. Inorg Chem 2017; 56:3302-3309. [DOI: 10.1021/acs.inorgchem.6b02665] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Md. Hafizur Rahman
- Marquette University Chemistry Department, PO Box 1881, Milwaukee, Wisconsin 53201, United States
| | - Michael D. Ryan
- Marquette University Chemistry Department, PO Box 1881, Milwaukee, Wisconsin 53201, United States
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27
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Blomberg MRA. Can Reduction of NO to N2O in Cytochrome c Dependent Nitric Oxide Reductase Proceed through a Trans-Mechanism? Biochemistry 2016; 56:120-131. [DOI: 10.1021/acs.biochem.6b00788] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Margareta R. A. Blomberg
- Department of Organic Chemistry,
Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
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28
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Malko D, Kucernak A, Lopes T. Performance of Fe–N/C Oxygen Reduction Electrocatalysts toward NO2–, NO, and NH2OH Electroreduction: From Fundamental Insights into the Active Center to a New Method for Environmental Nitrite Destruction. J Am Chem Soc 2016; 138:16056-16068. [DOI: 10.1021/jacs.6b09622] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Daniel Malko
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Anthony Kucernak
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Thiago Lopes
- Fuel
Cells and Hydrogen Center, Nuclear and Energy Research Institute, IPEN-CNEN/SP, Sao Paulo-SP 05508-000, Brazil
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29
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Bhagi-Damodaran A, Petrik I, Lu Y. Using Biosynthetic Models of Heme-Copper Oxidase and Nitric Oxide Reductase in Myoglobin to Elucidate Structural Features Responsible for Enzymatic Activities. Isr J Chem 2016; 56:773-790. [PMID: 27994254 PMCID: PMC5161413 DOI: 10.1002/ijch.201600033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In biology, a heme-Cu center in heme-copper oxidases (HCOs) is used to catalyze the four-electron reduction of oxygen to water, while a heme-nonheme diiron center in nitric oxide reductases (NORs) is employed to catalyze the two-electron reduction of nitric oxide to nitrous oxide. Although much progress has been made in biochemical and biophysical studies of HCOs and NORs, structural features responsible for similarities and differences within the two enzymatic systems remain to be understood. Here, we discuss the progress made in the design and characterization of myoglobin-based enzyme models of HCOs and NORs. In particular, we focus on use of these models to understand the structure-function relations between HCOs and NORs, including the role of nonheme metals, conserved amino acids in the active site, heme types and hydrogen-bonding network in tuning enzymatic activities and total turnovers. Insights gained from these studies are summarized and future directions are proposed.
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Affiliation(s)
| | - Igor Petrik
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL. 61801
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL. 61801
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30
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Bhagi-Damodaran A, Hosseinzadeh P, Mirts E, Reed J, Petrik ID, Lu Y. Design of Heteronuclear Metalloenzymes. Methods Enzymol 2016; 580:501-37. [PMID: 27586347 PMCID: PMC5156654 DOI: 10.1016/bs.mie.2016.05.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Heteronuclear metalloenzymes catalyze some of the most fundamentally interesting and practically useful reactions in nature. However, the presence of two or more metal ions in close proximity in these enzymes makes them more difficult to prepare and study than homonuclear metalloenzymes. To meet these challenges, heteronuclear metal centers have been designed into small and stable proteins with rigid scaffolds to understand how these heteronuclear centers are constructed and the mechanism of their function. This chapter describes methods for designing heterobinuclear metal centers in a protein scaffold by giving specific examples of a few heme-nonheme bimetallic centers engineered in myoglobin and cytochrome c peroxidase. We provide step-by-step procedures on how to choose the protein scaffold, design a heterobinuclear metal center in the protein scaffold computationally, incorporate metal ions into the protein, and characterize the resulting metalloproteins, both structurally and functionally. Finally, we discuss how an initial design can be further improved by rationally tuning its secondary coordination sphere, electron/proton transfer rates, and the substrate affinity.
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Affiliation(s)
- A Bhagi-Damodaran
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - P Hosseinzadeh
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - E Mirts
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - J Reed
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - I D Petrik
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Y Lu
- University of Illinois at Urbana-Champaign, Urbana, IL, United States.
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Matsumura H, Chakraborty S, Reed J, Lu Y, Moënne-Loccoz P. Effect of Outer-Sphere Side Chain Substitutions on the Fate of the trans Iron-Nitrosyl Dimer in Heme/Nonheme Engineered Myoglobins (Fe(B)Mbs): Insights into the Mechanism of Denitrifying NO Reductases. Biochemistry 2016; 55:2091-9. [PMID: 27003474 DOI: 10.1021/acs.biochem.5b01109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Denitrifying NO reductases are transmembrane protein complexes that utilize a heme/nonheme diiron center at their active sites to reduce two NO molecules to the innocuous gas N2O. Fe(B)Mb proteins, with their nonheme iron sites engineered into the heme distal pocket of sperm whale myoglobin, are attractive models for studying the molecular details of the NO reduction reaction. Spectroscopic and structural studies of Fe(B)Mb constructs have confirmed that they reproduce the metal coordination spheres observed at the active site of the cytochrome c-dependent NO reductase from Pseudomonas aeruginosa. Exposure of Fe(B)Mb to excess NO, as examined by analytical and spectroscopic techniques, results primarily in the formation of a five-coordinate heme-nitrosyl complex without N2O production. However, substitution of the outer-sphere residue Ile107 with a glutamic acid (i.e., I107E) decreases the formation rate of the five-coordinate heme-nitrosyl complex and allows for the substoichiometric production of N2O. Here, we aim to better characterize the formation of the five-coordinate heme-nitrosyl complex and to explain why the level of N2O production increases with the I107E substitution. We follow the formation of the five-coordinate heme-nitrosyl inhibitory complex through the sequential exposure of Fe(B)Mb to different NO isotopomers using rapid-freeze-quench resonance Raman spectroscopy. The data show that the complex is formed by the displacement of the proximal histidine by a new NO molecule after the weakening of the Fe(II)-His bond in the intermediate six-coordinate low-spin (6cLS) heme-nitrosyl complex. These results lead us to explore diatomic migration within the scaffold of myoglobin and whether substitutions at residue 107 can be sufficient to control access to the proximal heme cavities. Results on a new Fe(B)Mb construct with an I107F substitution (Fe(B)Mb3) show an increased rate for the formation of the five-coordinate low-spin heme-nitrosyl complex without N2O production. Taken together, our results suggest that production of N2O from the [6cLS heme {FeNO}(7)/{Fe(B)NO}(7)] trans iron-nitrosyl dimer intermediate requires a proton transfer event facilitated by an outer-sphere residue such as E107 in Fe(B)Mb2 and E280 in P. aeruginosa cNOR.
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Affiliation(s)
- Hirotoshi Matsumura
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University , Portland, Oregon 97239, United States
| | - Saumen Chakraborty
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Julian Reed
- Department of Biochemistry, 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.,Department of Biochemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Pierre Moënne-Loccoz
- Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University , Portland, Oregon 97239, United States
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32
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Chuang CH, Liaw WF, Hung CH. Conversion of Nitric Oxide into Nitrous Oxide as Triggered by the Polarization of Coordinated NO by Hydrogen Bonding. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201512063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chuan-Hung Chuang
- Institute of Chemistry; Academia Sinica; Nankang 11529 Taipei Taiwan
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Chen-Hsiung Hung
- Institute of Chemistry; Academia Sinica; Nankang 11529 Taipei Taiwan
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33
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Chuang CH, Liaw WF, Hung CH. Conversion of Nitric Oxide into Nitrous Oxide as Triggered by the Polarization of Coordinated NO by Hydrogen Bonding. Angew Chem Int Ed Engl 2016; 55:5190-4. [DOI: 10.1002/anie.201512063] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 02/08/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Chuan-Hung Chuang
- Institute of Chemistry; Academia Sinica; Nankang 11529 Taipei Taiwan
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Wen-Feng Liaw
- Department of Chemistry; National Tsing Hua University; Hsinchu 30013 Taiwan
| | - Chen-Hsiung Hung
- Institute of Chemistry; Academia Sinica; Nankang 11529 Taipei Taiwan
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34
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Petrik ID, Davydov R, Ross M, Zhao X, Hoffman B, Lu Y. Spectroscopic and Crystallographic Evidence for the Role of a Water-Containing H-Bond Network in Oxidase Activity of an Engineered Myoglobin. J Am Chem Soc 2016; 138:1134-7. [PMID: 26716352 PMCID: PMC4750474 DOI: 10.1021/jacs.5b12004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heme-copper oxidases (HCOs) catalyze efficient reduction of oxygen to water in biological respiration. Despite progress in studying native enzymes and their models, the roles of non-covalent interactions in promoting this activity are still not well understood. Here we report EPR spectroscopic studies of cryoreduced oxy-F33Y-CuBMb, a functional model of HCOs engineered in myoglobin (Mb). We find that cryoreduction at 77 K of the O2-bound form, trapped in the conformation of the parent oxyferrous form, displays a ferric-hydroperoxo EPR signal, in contrast to the cryoreduced oxy-wild-type (WT) Mb, which is unable to deliver a proton and shows a signal from the peroxo-ferric state. Crystallography of oxy-F33Y-CuBMb reveals an extensive H-bond network involving H2O molecules, which is absent from oxy-WTMb. This H-bonding proton-delivery network is the key structural feature that transforms the reversible oxygen-binding protein, WTMb, into F33Y-CuBMb, an oxygen-activating enzyme that reduces O2 to H2O. These results provide direct evidence of the importance of H-bond networks involving H2O in conferring enzymatic activity to a designed protein. Incorporating such extended H-bond networks in designing other metalloenzymes may allow us to confer and fine-tune their enzymatic activities.
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Affiliation(s)
- Igor D Petrik
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Roman Davydov
- The Department of Chemistry, Northwestern University , Evanston, Illinois 60201, United States
| | - Matthew Ross
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.,The Department of Chemistry, Northwestern University , Evanston, Illinois 60201, United States
| | - Xuan Zhao
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Brian Hoffman
- The Department of Chemistry, Northwestern University , Evanston, Illinois 60201, United States
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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Xu N, Abucayon EG, Powell DR, Richter-Addo GB. A bridged di-iron porphyrin hyponitrite complex as a model for biological N2O production from hyponitrite. Nitric Oxide 2015; 52:16-20. [PMID: 26529479 DOI: 10.1016/j.niox.2015.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 10/20/2015] [Accepted: 10/27/2015] [Indexed: 11/30/2022]
Abstract
Heme-hyponitrites are intermediates that form at the bimetallic active sites of bacterial nitric oxide reductases. To probe a possible effect of the Fe-Fe distance on hyponitrite stability, we prepared a bridged bis-porphyrin Fe-hyponitrite compound, namely [(OEP-CH2)Fe]2(μ2,η(1),η(1)-ONNO). Its υNO of 992 cm(-1) (υ15NO of 976 cm(-1)) is close to the υNO of 983 cm(-1) reported previously by us for the crystallographically characterized [(OEP)Fe]2(μ2,η(1),η(1)-ONNO) compound. The bridged bis-porphyrin Fe-hyponitrite complex is unstable with respect to N2O production, supporting the role of the bis-Fe porphyrin system in hyponitrite conversion to N2O. The preparation and crystallographic determination of the bridging sulfato derivative is also reported.
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Affiliation(s)
- Nan Xu
- Division of Mathematics and Natural Sciences, Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601, USA; Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019, USA.
| | - Erwin G Abucayon
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019, USA
| | - Douglas R Powell
- 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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36
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Structure and properties of the catalytic site of nitric oxide reductase at ambient temperature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1240-4. [DOI: 10.1016/j.bbabio.2015.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/13/2015] [Accepted: 06/29/2015] [Indexed: 11/24/2022]
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37
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Chakraborty S, Reed J, Sage JT, Branagan NC, Petrik ID, Miner KD, Hu MY, Zhao J, Alp EE, Lu Y. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies. Inorg Chem 2015; 54:9317-29. [PMID: 26274098 PMCID: PMC4677664 DOI: 10.1021/acs.inorgchem.5b01105] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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This Forum Article focuses on recent
advances in structural and spectroscopic studies of biosynthetic models
of nitric oxide reductases (NORs). NORs are complex metalloenzymes
found in the denitrification pathway of Earth’s nitrogen cycle
where they catalyze the proton-dependent two-electron reduction of
nitric oxide (NO) to nitrous oxide (N2O). While much progress
has been made in biochemical and biophysical studies of native NORs
and their variants, a clear mechanistic understanding of this important
metalloenzyme related to its function is still elusive. We report
herein UV–vis and nuclear resonance vibrational spectroscopy
(NRVS) studies of mononitrosylated intermediates of the NOR reaction
of a biosynthetic model. The ability to selectively substitute metals
at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation
of analogues of stable reaction intermediates by replacing either
metal with a redox inactive metal. Together with previous structural
and spectroscopic results, we summarize insights gained from studying
these biosynthetic models toward understanding structural features
responsible for the NOR activity and its mechanism. The outlook on
NOR modeling is also discussed, with an emphasis on the design of
models capable of catalytic turnovers designed based on close mimics
of the secondary coordination sphere of native NORs. New insights into nitric oxide reductases (NORs) are obtained. Using
nuclear resonance vibrational spectroscopy, we probe both iron atoms
in mononitrosylated intermediates of the NOR reaction in a biosynthetic
protein model that reveal new insights into the structural and electronic
features responsible for the NOR activity and its likely mechanism.
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Affiliation(s)
| | | | - J Timothy Sage
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
| | - Nicole C Branagan
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
| | | | | | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - E Ercan Alp
- Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
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38
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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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Servid AE, McKay AL, Davis CA, Garton EM, Manole A, Dobbin PS, Hough MA, Andrew CR. Resonance Raman Spectra of Five-Coordinate Heme-Nitrosyl Cytochromes c′: Effect of the Proximal Heme-NO Environment. Biochemistry 2015; 54:3320-7. [DOI: 10.1021/acs.biochem.5b00227] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amy E. Servid
- Department of Chemistry & Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Alison L. McKay
- Department of Chemistry & Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Cherry A. Davis
- Department of Chemistry & Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Elizabeth M. Garton
- Department of Chemistry & Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Andreea Manole
- School
of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Paul S. Dobbin
- School
of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Michael A. Hough
- School
of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Colin R. Andrew
- Department of Chemistry & Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
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40
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Jiang Y, Hayashi T, Matsumura H, Do LH, Majumdar A, Lippard SJ, Moënne-Loccoz P. Light-induced N₂O production from a non-heme iron-nitrosyl dimer. J Am Chem Soc 2014; 136:12524-7. [PMID: 25158917 PMCID: PMC4160282 DOI: 10.1021/ja504343t] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
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Two
non-heme iron–nitrosyl species, [Fe2(N-Et-HPTB)(O2CPh)(NO)2](BF4)2 (1a) and [Fe2(N-Et-HPTB)(DMF)2(NO)(OH)](BF4)3 (2a), are characterized by FTIR
and resonance Raman spectroscopy. Binding of NO is reversible in both
complexes, which are prone to NO photolysis under visible light illumination.
Photoproduction of N2O occurs in high yield for 1a but not 2a. Low-temperature FTIR photolysis experiments
with 1a in acetonitrile do not reveal any intermediate
species, but in THF at room temperature, a new {FeNO}7 species
quickly forms under illumination and exhibits a ν(NO) vibration
indicative of nitroxyl-like character. This metastable species reacts
further under illumination to produce N2O. A reaction mechanism
is proposed, and implications for NO reduction in flavodiiron
proteins are discussed.
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Affiliation(s)
- Yunbo Jiang
- Institute of Environmental Health, Oregon Health and Science University , Portland, Oregon 97239, United States
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