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Hird K, Campeciño JO, Lehnert N, Hegg EL. Recent mechanistic developments for cytochrome c nitrite reductase, the key enzyme in the dissimilatory nitrate reduction to ammonium pathway. J Inorg Biochem 2024; 256:112542. [PMID: 38631103 DOI: 10.1016/j.jinorgbio.2024.112542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/19/2024] [Accepted: 03/23/2024] [Indexed: 04/19/2024]
Abstract
Cytochrome c nitrite reductase, NrfA, is a soluble, periplasmic pentaheme cytochrome responsible for the reduction of nitrite to ammonium in the Dissimilatory Nitrate Reduction to Ammonium (DNRA) pathway, a vital reaction in the global nitrogen cycle. NrfA catalyzes this six-electron and eight-proton reduction of nitrite at a single active site with the help of its quinol oxidase partners. In this review, we summarize the latest progress in elucidating the reaction mechanism of ammonia production, including new findings about the active site architecture of NrfA, as well as recent results that elucidate electron transfer and storage in the pentaheme scaffold of this enzyme.
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Affiliation(s)
- Krystina Hird
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Julius O Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Eric L Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, USA.
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2
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Deng Y, Carnevale V, Ditchfield R, Pletneva EV. Applications of the Newly Developed Force-Field Parameters Uncover a Dynamic Nature of Ω-Loop C in the Lys-Ligated Alkaline Form of Cytochrome c. J Phys Chem B 2024; 128:5935-5949. [PMID: 38864552 DOI: 10.1021/acs.jpcb.4c00625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Lys-ligated cytochromes make up an emerging family of heme proteins. Density functional theory calculations on the amine/imidazole-ligated c-type ferric heme were employed to develop force-field parameters for molecular dynamics (MD) simulations of structural and dynamic features of these proteins. The new force-field parameters were applied to the alkaline form of yeast iso-1 cytochrome c to rationalize discrepancies resulting from distinct experimental conditions in prior structural studies and to provide insights into the mechanisms of the alkaline transition. Our simulations have revealed the dynamic nature of Ω-loop C in the Lys-ligated protein and its unfolding in the Lys-ligated conformer having this loop in the same position as in the native Met-ligated protein. The proximity of Tyr67 or Tyr74 to the Lys ligand of ferric heme iron suggests a possible mechanism of the backward alkaline transition where a proton donor Tyr assists in Lys dissociation. The developed force-field parameters will be useful in structural and dynamic characterization of other native or engineered Lys-ligated heme proteins.
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Affiliation(s)
- Yunling Deng
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Vincenzo Carnevale
- Institute for Genomics and Evolutionary Medicine, Institute for Computational Molecular Science, and Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Robert Ditchfield
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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3
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Denkhaus L, Siffert F, Einsle O. An unusual active site architecture in cytochrome c nitrite reductase NrfA-1 from Geobacter metallireducens. FEMS Microbiol Lett 2023; 370:fnad068. [PMID: 37460131 DOI: 10.1093/femsle/fnad068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/21/2023] [Accepted: 07/14/2023] [Indexed: 08/13/2023] Open
Abstract
Dissimilatory nitrate reduction to ammonia (DNRA) is a central pathway in the biogeochemical nitrogen cycle, allowing for the utilization of nitrate or nitrite as terminal electron acceptors. In contrast to the competing denitrification to N2, a major part of the essential nutrient nitrogen in DNRA is retained within the ecosystem and made available as ammonium to serve as a nitrogen source for other organisms. The second step of DNRA is mediated by the pentahaem cytochrome c nitrite reductase NrfA that catalyzes the six-electron reduction of nitrite to ammonium and is widely distributed among bacteria. A recent crystal structure of an NrfA ortholog from Geobacter lovleyi was the first characterized representative of a novel subclass of NrfA enzymes that lacked the canonical Ca2+ ion close to the active site haem 1. Here, we report the structural and functional characterization of NrfA from the closely related G. metallireducens. We established the recombinant production of catalytically active NrfA with its unique, lysine-coordinated active site haem heterologously in Escherichia coli and determined its three-dimensional structure by X-ray crystallography to 1.9 Å resolution. The structure confirmed GmNrfA as a further calcium-independent NrfA protein, and it also shows an altered active site that contained an unprecedented aspartate residue, D80, close to the substrate-binding site. This residue formed part of a loop that also caused a changed arrangement of the conserved substrate/product channel relative to other NrfA proteins and rendered the protein insensitive to the inhibitor sulphate. To elucidate the relevance of D80, we produced and studied the variants D80A and D80N that showed significantly reduced catalytic activity.
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Affiliation(s)
- Lukas Denkhaus
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Fanny Siffert
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg im Breisgau, Germany
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Zhang Q, Tian F, Zhou Q, Zhang C, Tang S, Jiang L, Du S. Targeted ginkgo kernel biomass precursor using eco-friendly synthesis of efficient carbon quantum dots for detection of trace nitrite ions and cell imaging. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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5
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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: 96] [Impact Index Per Article: 32.0] [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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6
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Kroneck PMH. Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen. J Biol Inorg Chem 2021; 27:1-21. [PMID: 34865208 PMCID: PMC8840924 DOI: 10.1007/s00775-021-01921-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/22/2021] [Indexed: 12/26/2022]
Abstract
Since the characterization of cytochrome c552 as a multiheme nitrite reductase, research on this enzyme has gained major interest. Today, it is known as pentaheme cytochrome c nitrite reductase (NrfA). Part of the NH4+ produced from NO2- is released as NH3 leading to nitrogen loss, similar to denitrification which generates NO, N2O, and N2. NH4+ can also be used for assimilatory purposes, thus NrfA contributes to nitrogen retention. It catalyses the six-electron reduction of NO2- to NH4+, hosting four His/His ligated c-type hemes for electron transfer and one structurally differentiated active site heme. Catalysis occurs at the distal side of a Fe(III) heme c proximally coordinated by lysine of a unique CXXCK motif (Sulfurospirillum deleyianum, Wolinella succinogenes) or, presumably, by the canonical histidine in Campylobacter jejeuni. Replacement of Lys by His in NrfA of W. succinogenes led to a significant loss of enzyme activity. NrfA forms homodimers as shown by high resolution X-ray crystallography, and there exist at least two distinct electron transfer systems to the enzyme. In γ-proteobacteria (Escherichia coli) NrfA is linked to the menaquinol pool in the cytoplasmic membrane through a pentaheme electron carrier (NrfB), in δ- and ε-proteobacteria (S. deleyianum, W. succinogenes), the NrfA dimer interacts with a tetraheme cytochrome c (NrfH). Both form a membrane-associated respiratory complex on the extracellular side of the cytoplasmic membrane to optimize electron transfer efficiency. This minireview traces important steps in understanding the nature of pentaheme cytochrome c nitrite reductases, and discusses their structural and functional features.
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Affiliation(s)
- Peter M H Kroneck
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
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Shahid S, Ali M, Legaspi-Humiston D, Wilcoxen J, Pacheco AA. A Kinetic Investigation of the Early Steps in Cytochrome c Nitrite Reductase (ccNiR)-Catalyzed Reduction of Nitrite. Biochemistry 2021; 60:2098-2115. [PMID: 34143605 DOI: 10.1021/acs.biochem.1c00172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The decaheme enzyme cytochrome c nitrite reductase (ccNiR) catalyzes reduction of nitrite to ammonium in a six-electron, eight-proton process. With a strong reductant as the electron source, ammonium is the sole product. However, intermediates accumulate when weaker reductants are employed, facilitating study of the ccNiR mechanism. Herein, the early stages of Shewanella oneidensis ccNiR-catalyzed nitrite reduction were investigated by using the weak reductants N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and ferrocyanide. In stopped-flow experiments, reduction of nitrite-loaded ccNiR by TMPD generated a transient intermediate, identified as FeH1II(NO2-), where FeH1 represents the ccNiR active site. FeH1II(NO2-) accumulated rapidly and was then more slowly converted to the two-electron-reduced moiety {FeH1NO}7; ccNiR was not reduced beyond the {FeH1NO}7 state. The midpoint potentials for sequential reduction of FeH1III(NO2-) to FeH1II(NO2-) and then to {FeH1NO}7 were estimated to be 130 and 370 mV versus the standard hydrogen electrode, respectively. FeH1II(NO2-) does not accumulate at equilibrium because its reduction to {FeH1NO}7 is so much easier than the reduction of FeH1III(NO2-) to FeH1II(NO2-). With weak reductants, free NO• was released from nitrite-loaded ccNiR. The release of NO• from {FeH1NO}7 is exceedingly slow (k ∼ 0.001 s-1), but it is somewhat faster (k ∼ 0.050 s-1) while FeH1III(NO2-) is being reduced to {FeH1NO}7; then, the release of NO• from the undetectable transient {FeH1NO}6 can compete with reduction of {FeH1NO}6 to {FeH1NO}7. CcNiR appears to be optimized to capture nitrite and minimize the release of free NO•. Nitrite capture is achieved by reducing bound nitrite with even weak electron donors, while NO• release is minimized by stabilizing the substitutionally inert {FeH1NO}7 over the more labile {FeH1NO}6.
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Affiliation(s)
- Shahid Shahid
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Mahbbat Ali
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Desiree Legaspi-Humiston
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Jarett Wilcoxen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - A Andrew Pacheco
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
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Amanullah S, Saha P, Nayek A, Ahmed ME, Dey A. Biochemical and artificial pathways for the reduction of carbon dioxide, nitrite and the competing proton reduction: effect of 2nd sphere interactions in catalysis. Chem Soc Rev 2021; 50:3755-3823. [DOI: 10.1039/d0cs01405b] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Reduction of oxides and oxoanions of carbon and nitrogen are of great contemporary importance as they are crucial for a sustainable environment.
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Affiliation(s)
- Sk Amanullah
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Paramita Saha
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Abhijit Nayek
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Md Estak Ahmed
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
| | - Abhishek Dey
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata
- India
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Campeciño J, Lagishetty S, Wawrzak Z, Sosa Alfaro V, Lehnert N, Reguera G, Hu J, Hegg EL. Cytochrome c nitrite reductase from the bacterium Geobacter lovleyi represents a new NrfA subclass. J Biol Chem 2020; 295:11455-11465. [PMID: 32518164 PMCID: PMC7450111 DOI: 10.1074/jbc.ra120.013981] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/07/2020] [Indexed: 01/07/2023] Open
Abstract
Cytochrome c nitrite reductase (NrfA) catalyzes the reduction of nitrite to ammonium in the dissimilatory nitrate reduction to ammonium (DNRA) pathway, a process that competes with denitrification, conserves nitrogen, and minimizes nutrient loss in soils. The environmental bacterium Geobacter lovleyi has recently been recognized as a key driver of DNRA in nature, but its enzymatic pathway is still uncharacterized. To address this limitation, here we overexpressed, purified, and characterized G. lovleyi NrfA. We observed that the enzyme crystallizes as a dimer but remains monomeric in solution. Importantly, its crystal structure at 2.55-Å resolution revealed the presence of an arginine residue in the region otherwise occupied by calcium in canonical NrfA enzymes. The presence of EDTA did not affect the activity of G. lovleyi NrfA, and site-directed mutagenesis of this arginine reduced enzymatic activity to <3% of the WT levels. Phylogenetic analysis revealed four separate emergences of Arg-containing NrfA enzymes. Thus, the Ca2+-independent, Arg-containing NrfA from G. lovleyi represents a new subclass of cytochrome c nitrite reductase. Most genera from the exclusive clades of Arg-containing NrfA proteins are also represented in clades containing Ca2+-dependent enzymes, suggesting convergent evolution.
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Affiliation(s)
- Julius Campeciño
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Satyanarayana Lagishetty
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois, USA
| | - Victor Sosa Alfaro
- Department of Chemistry and Biophysics, The University of Michigan, Ann Arbor, Michigan, USA
| | - Nicolai Lehnert
- Department of Chemistry and Biophysics, The University of Michigan, Ann Arbor, Michigan, USA
| | - Gemma Reguera
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jian Hu
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,Department of Chemistry, Michigan State University, East Lansing, Michigan, USA
| | - Eric L. Hegg
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, Michigan, USA,For correspondence: Eric L. Hegg,
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Expression, characterization and molecular docking of the assimilatory NaDH-nitrite reductase from Acidovorax wautersii QZ-4. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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11
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Amanullah S, Dey A. The role of porphyrin peripheral substituents in determining the reactivities of ferrous nitrosyl species. Chem Sci 2020; 11:5909-5921. [PMID: 32832056 PMCID: PMC7407271 DOI: 10.1039/d0sc01625j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/07/2020] [Indexed: 12/02/2022] Open
Abstract
Ferrous nitrosyl {FeNO}7 species is an intermediate common to the catalytic cycles of Cd1NiR and CcNiR, two heme-based nitrite reductases (NiR), and its reactivity varies dramatically in these enzymes.
Ferrous nitrosyl {FeNO}7 species is an intermediate common to the catalytic cycles of Cd1NiR and CcNiR, two heme-based nitrite reductases (NiR), and its reactivity varies dramatically in these enzymes. The former reduces NO2– to NO in the denitrification pathway while the latter reduces NO2– to NH4+ in a dissimilatory nitrite reduction. With very similar electron transfer partners and heme based active sites, the origin of this difference in reactivity has remained unexplained. Differences in the structure of the heme d1 (Cd1NiR), which bears electron-withdrawing groups and has saturated pyrroles, relative to heme c (CcNiR) are often invoked to explain these reactivities. A series of iron porphyrinoids, designed to model the electron-withdrawing peripheral substitution as well as the saturation present in heme d1 in Cd1NiR, and their NO adducts were synthesized and their properties were investigated. The data clearly show that the presence of electron-withdrawing groups (EWGs) and saturated pyrroles together in a synthetic porphyrinoid (FeDEsC) weakens the Fe–NO bond in {FeNO}7 adducts along with decreasing the bond dissociation free energies (BDFENH) of the {FeHNO}8 species. The EWG raises the E° of the {FeNO}7/8 process, making the electron transfer (ET) facile, but decreases the pKa of {FeNO}8 species, making protonation (PT) difficult, while saturation has the opposite effect. The weakening of the Fe–NO bonding biases the {FeNO}7 species of FeDEsC for NO dissociation, as in Cd1NiR, which is otherwise set-up for a proton-coupled electron transfer (PCET) to form an {FeHNO}8 species eventually leading to its further reduction to NH4+.
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Affiliation(s)
- Sk Amanullah
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja SC Mullick Road , Kolkata , India - 700032 .
| | - Abhishek Dey
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A & 2B Raja SC Mullick Road , Kolkata , India - 700032 .
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