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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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Sarkar A, Bhakta S, Chattopadhyay S, Dey A. Role of distal arginine residue in the mechanism of heme nitrite reductases. Chem Sci 2023; 14:7875-7886. [PMID: 37502318 PMCID: PMC10370594 DOI: 10.1039/d3sc01777j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/14/2023] [Indexed: 07/29/2023] Open
Abstract
Heme nitrite reductases reduce NO2- by 1e-/2H+ to NO or by 6e-/8H+ to NH4+ which are key steps in the global nitrogen cycle. Second-sphere residues, such as arginine (with a guanidine head group), are proposed to play a key role in the reaction by assisting substrate binding and hydrogen bonding and by providing protons to the active site for the reaction. The reactivity of an iron porphyrin with a NO2- covalently attached to a guanidinium arm in its 2nd sphere was investigated to understand the role of arginine residues in the 2nd sphere of heme nitrite reductases. The presence of the guanidinium residue allows the synthetic ferrous porphyrin to reduce NO2- and produce a ferrous nitrosyl species ({FeNO}7), where the required protons are provided by the guanidinium group in the 2nd sphere. However, in the presence of additional proton sources in solution, the reaction of ferrous porphyrin with NO2- results in the formation of ferric porphyrin and the release of NO. Spectroscopic and kinetic data indicated that re-protonation of the guanidine group in the 2nd sphere by an external proton source causes NO to dissociate from a ferric nitrosyl species ({FeNO}6) at rates similar to those observed for enzymatic sites. This re-protonation of the guanidine group mimics the proton recharge mechanism in the active site of NiR. DFT calculations indicated that the lability of the Fe-NO bond in the {FeNO}6 species is derived from the greater binding affinity of anions (e.g. NO2-) to the ferric center relative to neutral NO due to hydrogen bonding and electrostatic interaction of these bound anions with the protonated guanidium group in the 2nd sphere. The reduced {FeNO}7 species, once formed, is not affected significantly by the re-protonation of the guanidine residue. These results provide direct insight into the role of the 2nd sphere arginine residue present in the active sites of heme-based NiRs in determining the fate of NO2- reduction. Specifically, the findings using the synthetic model suggest that rapid re-protonation of these arginine residues may trigger the dissociation of NO from the {FeNO}6, which may also be the case in the protein active site.
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Affiliation(s)
- Ankita Sarkar
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road Kolkata WB 700032 India
| | - Snehadri Bhakta
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road Kolkata WB 700032 India
| | - Samir Chattopadhyay
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road Kolkata WB 700032 India
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road Kolkata WB 700032 India
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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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5
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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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6
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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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8
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Updating NO •/HNO interconversion under physiological conditions: A biological implication overview. J Inorg Biochem 2020; 216:111333. [PMID: 33385637 DOI: 10.1016/j.jinorgbio.2020.111333] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/13/2020] [Accepted: 12/05/2020] [Indexed: 12/12/2022]
Abstract
Azanone (HNO/NO-), also called nitroxyl, is a highly reactive compound whose biological role is still a matter of debate. A key issue that remains to be clarified regarding HNO and its biological activity is that of its endogenous formation. Given the overlap of the molecular targets and reactivity of nitric oxide (NO•) and HNO, its chemical biology was perceived to be similar to that of NO• as a biological signaling agent. However, despite their closely related reactivity, NO• and HNO's biochemical pathways are quite different. Moreover, the reduction of nitric oxide to azanone is possible but necessarily coupled to other reactions, which drive the reaction forward, overcoming the unfavorable thermodynamic barrier. The mechanism of this NO•/HNO interplay and its downstream effects in different contexts were studied recently, showing that more than fifteen moderate reducing agents react with NO• producing HNO. Particularly, it is known that the reaction between nitric oxide and hydrogen sulfide (H2S) produces HNO. However, this rate constant was not reported yet. In this work, firstly the NO•/H2S effective rate constant was measured as a function of the pH. Then, the implications of these chemical (non-enzymatic), biologically compatible, routes to endogenous HNO formation was discussed. There is no doubt that HNO could be (is?) a new endogenously produced messenger that mediates specific physiological responses, many of which were attributed yet to direct NO• effects.
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Andoralov V, Shleev S, Dergousova N, Kulikova O, Popov V, Tikhonova T. Octaheme nitrite reductase: The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction. Bioelectrochemistry 2020; 138:107699. [PMID: 33221569 DOI: 10.1016/j.bioelechem.2020.107699] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 11/24/2022]
Abstract
Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
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Affiliation(s)
- Victor Andoralov
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden
| | - Sergey Shleev
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden; Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Natalia Dergousova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Olga Kulikova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Vladimir Popov
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; Kurchatov NBIC Centre, National Research Centre "Kurchatov Institute", 123182 Moscow, Russia
| | - Tamara Tikhonova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
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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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11
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Seefeldt LC, Yang ZY, Lukoyanov DA, Harris DF, Dean DR, Raugei S, Hoffman BM. Reduction of Substrates by Nitrogenases. Chem Rev 2020; 120:5082-5106. [PMID: 32176472 DOI: 10.1021/acs.chemrev.9b00556] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nitrogenase is the enzyme that catalyzes biological N2 reduction to NH3. This enzyme achieves an impressive rate enhancement over the uncatalyzed reaction. Given the high demand for N2 fixation to support food and chemical production and the heavy reliance of the industrial Haber-Bosch nitrogen fixation reaction on fossil fuels, there is a strong need to elucidate how nitrogenase achieves this difficult reaction under benign conditions as a means of informing the design of next generation synthetic catalysts. This Review summarizes recent progress in addressing how nitrogenase catalyzes the reduction of an array of substrates. New insights into the mechanism of N2 and proton reduction are first considered. This is followed by a summary of recent gains in understanding the reduction of a number of other nitrogenous compounds not considered to be physiological substrates. Progress in understanding the reduction of a wide range of C-based substrates, including CO and CO2, is also discussed, and remaining challenges in understanding nitrogenase substrate reduction are considered.
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Affiliation(s)
- Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Dmitriy A Lukoyanov
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Derek F Harris
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Dennis R Dean
- Biochemistry Department, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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12
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Ali M, Stein N, Mao Y, Shahid S, Schmidt M, Bennett B, Pacheco AA. Trapping of a Putative Intermediate in the Cytochrome c Nitrite Reductase (ccNiR)-Catalyzed Reduction of Nitrite: Implications for the ccNiR Reaction Mechanism. J Am Chem Soc 2019; 141:13358-13371. [DOI: 10.1021/jacs.9b03036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mahbbat Ali
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Natalia Stein
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Yingxi Mao
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Shahid Shahid
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Marius Schmidt
- Department of Physics, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Brian Bennett
- Department of Physics, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - A. Andrew Pacheco
- Department of Chemistry and Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53211, United States
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13
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Lintuluoto M, Lintuluoto JM. Intra-electron transfer induced by protonation in copper-containing nitrite reductase. Metallomics 2018. [DOI: 10.1039/c7mt00323d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Electron transfer between two Cu sites in the enzyme induced by protonation of remote catalytic residues.
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Affiliation(s)
- Masami Lintuluoto
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University
- Kyoto 606-8522
- Japan
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14
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Lintuluoto M, Yamada C, Lintuluoto JM. QM/MM Calculation of the Enzyme Catalytic Cycle Mechanism for Copper- and Zinc-Containing Superoxide Dismutase. J Phys Chem B 2017; 121:7235-7246. [DOI: 10.1021/acs.jpcb.7b03589] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masami Lintuluoto
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho, Sakyo, Kyoto 606-8522, Japan
| | - Chiaki Yamada
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho, Sakyo, Kyoto 606-8522, Japan
| | - Juha M. Lintuluoto
- Graduate
School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8530, Japan
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15
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Lintuluoto M, Lintuluoto JM. DFT Study on Enzyme Turnover Including Proton and Electron Transfers of Copper-Containing Nitrite Reductase. Biochemistry 2016; 55:4697-707. [DOI: 10.1021/acs.biochem.6b00423] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Masami Lintuluoto
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho,
Sakyo, Kyoto 606-8522, Japan
| | - Juha M. Lintuluoto
- Graduate
School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8530, Japan
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16
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Lintuluoto M, Lintuluoto JM. DFT Study on Nitrite Reduction Mechanism in Copper-Containing Nitrite Reductase. Biochemistry 2015; 55:210-23. [DOI: 10.1021/acs.biochem.5b00542] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Masami Lintuluoto
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho, Sakyo, Kyoto 606-8522, Japan
| | - Juha M. Lintuluoto
- Graduate
School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8530, Japan
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17
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Bykov D, Neese F. Six-Electron Reduction of Nitrite to Ammonia by Cytochrome c Nitrite Reductase: Insights from Density Functional Theory Studies. Inorg Chem 2015; 54:9303-16. [DOI: 10.1021/acs.inorgchem.5b01506] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Dmytro Bykov
- qLEAP Center
for Theoretical Chemistry, Department of Chemistry, Aarhus University, Gustav
Wieds Vej 10A, DK-8000 Aarhus C, Denmark
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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18
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Trofimov AA, Polyakov KM, Lazarenko VA, Popov AN, Tikhonova TV, Tikhonov AV, Popov VO. Structural study of the X-ray-induced enzymatic reaction of octahaem cytochromecnitrite reductase. ACTA ACUST UNITED AC 2015; 71:1087-94. [DOI: 10.1107/s1399004715003053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/12/2015] [Indexed: 11/10/2022]
Abstract
Octahaem cytochromecnitrite reductase from the bacteriumThioalkalivibrio nitratireducenscatalyzes the reduction of nitrite to ammonium and of sulfite to sulfide. The reducing properties of X-ray radiation and the high quality of the enzyme crystals allow study of the catalytic reaction of cytochromecnitrite reductase directly in a crystal of the enzyme, with the reaction being induced by X-rays. Series of diffraction data sets with increasing absorbed dose were collected from crystals of the free form of the enzyme and its complexes with nitrite and sulfite. The corresponding structures revealed gradual changes associated with the reduction of the catalytic haems by X-rays. In the case of the nitrite complex the conversion of the nitrite ions bound in the active sites to NO species was observed, which is the beginning of the catalytic reaction. For the free form, an increase in the distance between the oxygen ligand bound to the catalytic haem and the iron ion of the haem took place. In the case of the sulfite complex no enzymatic reaction was detected, but there were changes in the arrangement of the active-site water molecules that were presumably associated with a change in the protonation state of the sulfite ions.
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19
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Lockwood CWJ, Burlat B, Cheesman MR, Kern M, Simon J, Clarke TA, Richardson DJ, Butt JN. Resolution of Key Roles for the Distal Pocket Histidine in Cytochrome c Nitrite Reductases. J Am Chem Soc 2015; 137:3059-68. [DOI: 10.1021/ja512941j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | | | | | - Melanie Kern
- Microbial
Energy Conversion and Biotechnology, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany
| | - Jörg Simon
- Microbial
Energy Conversion and Biotechnology, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany
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20
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Doctorovich F, Bikiel DE, Pellegrino J, Suárez SA, Martí MA. Reactions of HNO with metal porphyrins: underscoring the biological relevance of HNO. Acc Chem Res 2014; 47:2907-16. [PMID: 25238532 DOI: 10.1021/ar500153c] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Azanone ((1)HNO, nitroxyl) shows interesting yet poorly understood chemical and biological effects. HNO has some overlapping properties with nitric oxide (NO), sharing its biological reactivity toward heme proteins, thiols, and oxygen. Despite this similarity, HNO and NO show significantly different pharmacological effects. The high reactivity of HNO means that studies must rely on the use of donor molecules such as trioxodinitrate (Angeli's salt). It has been suggested that azanone could be an intermediate in several reactions and that it may be an enzymatically produced signaling molecule. The inherent difficulty in detecting its presence unequivocally prevents evidence from yielding definite answers. On the other hand, metalloporphyrins are widely used as chemical models of heme proteins, providing us with invaluable tools for the study of the coordination chemistry of small molecules, like NO, CO, and O2. Studies with transition metal porphyrins have shown diverse mechanistic, kinetic, structural, and reactive aspects related to the formation of nitrosyl complexes. Porphyrins are also widely used in technical applications, especially when coupled to a surface, where they can be used as electrochemical gas sensors. Given their versatility, they have not escaped their role as key players in chemical studies involving HNO. This Account presents the research performed during the last 10 years in our group concerning azanone reactions with iron, manganese, and cobalt porphyrins. We begin by describing their HNO trapping capabilities, which result in formation of the corresponding nitrosyl complexes. Kinetic and mechanistic studies of these reactions show two alternative operating mechanisms: reaction of the metal center with HNO or with the donor. Moreover, we have also shown that azanone can be stabilized by coordination to iron porphyrins using electron-attracting substituents attached to the porphyrin ring, which balance the negatively charged NO¯. Second, we describe an electrochemical HNO sensing device based on the covalent attachment of a cobalt porphyrin to gold. A surface effect affects the redox potentials and allows discrimination between HNO and NO. The reaction with the former is fast, efficient, and selective, lacking spurious signals due to the presence of reactive nitrogen and oxygen species. The sensor is both biologically compatible and highly sensitive (nanomolar). This time-resolved detection allows kinetic analysis of reactions producing HNO. The sensor thus offers excellent opportunities to be used in experiments looking for HNO. As examples, we present studies concerning (a) HNO donation capabilities of new HNO donors as assessed by the sensor, (b) HNO detection as an intermediate in O atom abstraction to nitrite by phosphines, and (c) NO to HNO interconversion mediated by alcohols and thiols. Finally, we briefly discuss the key experiments required to demonstrate endogenous HNO formation to be done in the near future, involving the in vivo use of the HNO sensing device.
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Affiliation(s)
- Fabio Doctorovich
- Departamento de Química Inorgánica,
Analítica
y Química Física/INQUIMAE-CONICET and †Departamento de Química
Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II (1428), Buenos Aires, Argentina
| | - Damian E. Bikiel
- Departamento de Química Inorgánica,
Analítica
y Química Física/INQUIMAE-CONICET and †Departamento de Química
Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II (1428), Buenos Aires, Argentina
| | - Juan Pellegrino
- Departamento de Química Inorgánica,
Analítica
y Química Física/INQUIMAE-CONICET and †Departamento de Química
Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II (1428), Buenos Aires, Argentina
| | - Sebastián A. Suárez
- Departamento de Química Inorgánica,
Analítica
y Química Física/INQUIMAE-CONICET and †Departamento de Química
Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II (1428), Buenos Aires, Argentina
| | - Marcelo A. Martí
- Departamento de Química Inorgánica,
Analítica
y Química Física/INQUIMAE-CONICET and †Departamento de Química
Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II (1428), Buenos Aires, Argentina
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21
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Shaw S, Lukoyanov D, Danyal K, Dean DR, Hoffman BM, Seefeldt LC. Nitrite and hydroxylamine as nitrogenase substrates: mechanistic implications for the pathway of N₂ reduction. J Am Chem Soc 2014; 136:12776-83. [PMID: 25136926 PMCID: PMC4160268 DOI: 10.1021/ja507123d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
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Investigations of reduction of nitrite
(NO2–) to ammonia (NH3) by
nitrogenase indicate a limiting
stoichiometry, NO2– + 6e– + 12ATP + 7H+ → NH3 + 2H2O + 12ADP + 12Pi. Two intermediates freeze-trapped during
NO2– turnover by nitrogenase variants
and investigated by Q-band ENDOR/ESEEM are identical to states, denoted H and I, formed
on the pathway of N2 reduction. The proposed NO2– reduction intermediate hydroxylamine (NH2OH) is a nitrogenase substrate for which the H and I reduction intermediates
also can be trapped. Viewing N2 and NO2– reductions in light of their common reduction intermediates
and of NO2– reduction by multiheme cytochrome
c nitrite reductase (ccNIR) leads us to propose that NO2– reduction by nitrogenase begins with the generation
of NO2H bound to a state in which the active-site FeMo-co
(M) has accumulated two [e–/H+] (E2), stored as a (bridging) hydride and proton. Proton
transfer to NO2H and H2O loss leaves M–[NO+]; transfer of the E2 hydride to
the [NO+] directly to form HNO bound to FeMo-co is one
of two alternative means for avoiding formation of a terminal M–[NO] thermodynamic “sink”. The N2 and NO2– reduction pathways
converge upon reduction of NH2NH2 and NH2OH bound states to form state H with [−NH2] bound to M. Final reduction
converts H to I, with NH3 bound to M. The results
presented here, combined with the parallels with ccNIR, support a
N2 fixation mechanism in which liberation of the first
NH3 occurs upon delivery of five [e–/H+] to N2, but a total of seven [e–/H+] to FeMo-co when obligate H2 evolution
is considered, and not earlier in the reduction process.
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Affiliation(s)
- Sudipta Shaw
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322, United States
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22
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Judd ET, Stein N, Pacheco AA, Elliott SJ. Hydrogen bonding networks tune proton-coupled redox steps during the enzymatic six-electron conversion of nitrite to ammonia. Biochemistry 2014; 53:5638-46. [PMID: 25137350 PMCID: PMC4159211 DOI: 10.1021/bi500854p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
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Multielectron
multiproton reactions play an important role in both
biological systems and chemical reactions involved in energy storage
and manipulation. A key strategy employed by nature in achieving such
complex chemistry is the use of proton-coupled redox steps. Cytochrome c nitrite reductase (ccNiR) catalyzes the six-electron seven-proton
reduction of nitrite to ammonia. While a catalytic mechanism for ccNiR
has been proposed on the basis of studies combining computation and
crystallography, there have been few studies directly addressing the
nature of the proton-coupled events that are predicted to occur along
the nitrite reduction pathway. Here we use protein film voltammetry
to directly interrogate the proton-coupled steps that occur during
nitrite reduction by ccNiR. We find that conversion of nitrite to
ammonia by ccNiR adsorbed to graphite electrodes is defined by two
distinct phases; one is proton-coupled, and the other is not. Mutation
of key active site residues (H257, R103, and Y206) modulates these
phases and specifically alters the properties of the detected proton-dependent
step but does not inhibit the ability of ccNiR to conduct the full
reduction of nitrite to ammonia. We conclude that the active site
residues examined are responsible for tuning the protonation steps
that occur during catalysis, likely through an extensive hydrogen
bonding network, but are not necessarily required for the reaction
to proceed. These results provide important insight into how enzymes
can specifically tune proton- and electron transfer steps to achieve
high turnover numbers in a physiological pH range.
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Affiliation(s)
- Evan T Judd
- Department of Chemistry, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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23
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Speelman AL, Lehnert N. Heme versus non-heme iron-nitroxyl {FeN(H)O}⁸ complexes: electronic structure and biologically relevant reactivity. Acc Chem Res 2014; 47:1106-16. [PMID: 24555413 DOI: 10.1021/ar400256u] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Researchers have completed extensive studies on heme and non-heme iron-nitrosyl complexes, which are labeled {FeNO}(7) in the Enemark-Feltham notation, but they have had very limited success in producing corresponding, one-electron reduced, {FeNO}(8) complexes where a nitroxyl anion (NO(-)) is formally bound to an iron(II) center. These complexes, and their protonated iron(II)-NHO analogues, are proposed key intermediates in nitrite (NO2(-)) and nitric oxide (NO) reducing enzymes in bacteria and fungi. In addition, HNO is known to have a variety of physiological effects, most notably in the cardiovascular system. HNO may also serve as a signaling molecule in mammals. For these functions, iron-containing proteins may mediate the production of HNO and serve as receptors for HNO in vivo. In this Account, we highlight recent key advances in the preparation, spectroscopic characterization, and reactivity of ferrous heme and non-heme nitroxyl (NO(-)/HNO) complexes that have greatly enhanced our understanding of the potential biological roles of these species. Low-spin (ls) heme {FeNO}(7) complexes (S = 1/2) can be reversibly reduced to the corresponding {FeNO}(8) species, which are stable, diamagnetic compounds. Because the reduction is ligand (NO) centered in these cases, it occurs at extremely negative redox potentials that are at the edge of the biologically feasible range. Interestingly, the electronic structures of ls-{FeNO}(7) and ls-{FeNO}(8) species are strongly correlated with very similar frontier molecular orbitals (FMOs) and thermodynamically strong Fe-NO bonds. In contrast, high-spin (hs) non-heme {FeNO}(7) complexes (S = 3/2) can be reduced at relatively mild redox potentials. Here, the reduction is metal-centered and leads to a paramagnetic (S = 1) {FeNO}(8) complex. The increased electron density at the iron center in these species significantly decreases the covalency of the Fe-NO bond, making the reduced complexes highly reactive. In the absence of steric bulk, monomeric high-spin {FeNO}(8) complexes decompose rapidly. Notably, in a recently prepared, dimeric [{FeNO}(7)]2 species, we observed that reduction leads to rapid N-N bond formation and N2O generation, which directly models the reactivity of flavodiiron NO reductases (FNORs). We have also made key progress in the preparation and stabilization of corresponding HNO complexes, {FeNHO}(8), using both heme and non-heme ligand sets. In both cases, we have taken advantage of sterically bulky coligands to stabilize these species. ls-{FeNO}(8) complexes are basic and easily form corresponding ls-{FeNHO}(8) species, which, however, decompose rapidly via disproportionation and H2 release. Importantly, we recently showed that we can suppress this reaction via steric protection of the bound HNO ligand. As a result, we have demonstrated that ls-{FeNHO}(8) model complexes are stable and amenable to spectroscopic characterization. Neither ls-{FeNO}(8) nor ls-{FeNHO}(8) model complexes are active for N-N coupling, and hence, seem unsuitable as reactive intermediates in nitric oxide reductases (NORs). Hs-{FeNO}(8) complexes are more basic than their hs-{FeNO}(7) precursors, but their electronic structure and reactivity is not as well characterized.
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Affiliation(s)
- Amy L. Speelman
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicolai Lehnert
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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Affiliation(s)
- Luisa B. Maia
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - José J. G. Moura
- REQUIMTE/CQFB, Departamento
de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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25
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Blomberg MRA, Borowski T, Himo F, Liao RZ, Siegbahn PEM. Quantum chemical studies of mechanisms for metalloenzymes. Chem Rev 2014; 114:3601-58. [PMID: 24410477 DOI: 10.1021/cr400388t] [Citation(s) in RCA: 431] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Margareta R A Blomberg
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University , SE-106 91 Stockholm, Sweden
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26
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Abstract
The global biogeochemical nitrogen cycle is essential for life on Earth. Many of the underlying biotic reactions are catalyzed by a multitude of prokaryotic and eukaryotic life forms whereas others are exclusively carried out by microorganisms. The last century has seen the rise of a dramatic imbalance in the global nitrogen cycle due to human behavior that was mainly caused by the invention of the Haber-Bosch process. Its main product, ammonia, is a chemically reactive and biotically favorable form of bound nitrogen. The anthropogenic supply of reduced nitrogen to the biosphere in the form of ammonia, for example during environmental fertilization, livestock farming, and industrial processes, is mandatory in feeding an increasing world population. In this chapter, environmental ammonia pollution is linked to the activity of microbial metalloenzymes involved in respiratory energy metabolism and bioenergetics. Ammonia-producing multiheme cytochromes c are discussed as paradigm enzymes.
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Affiliation(s)
- Jörg Simon
- Microbial Energy Conversion and Biotechnology, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, D-64287, Darmstadt, Germany,
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27
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Historical Introduction to Nitrosyl Complexes. NITROSYL COMPLEXES IN INORGANIC CHEMISTRY, BIOCHEMISTRY AND MEDICINE I 2014. [DOI: 10.1007/430_2013_116] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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28
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Heme-bound nitroxyl, hydroxylamine, and ammonia ligands as intermediates in the reaction cycle of cytochrome c nitrite reductase: a theoretical study. J Biol Inorg Chem 2013; 19:97-112. [DOI: 10.1007/s00775-013-1065-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/05/2013] [Indexed: 11/25/2022]
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29
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Design and synthesis of novel 3,5-bis-N-(aryl/heteroaryl) carbamoyl-4-aryl-1,4-dihydropyridines as small molecule BACE-1 inhibitors. Bioorg Med Chem 2013; 21:6893-909. [DOI: 10.1016/j.bmc.2013.09.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 11/23/2022]
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30
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Contrasting catalytic profiles of multiheme nitrite reductases containing CxxCK heme-binding motifs. J Biol Inorg Chem 2013; 18:655-67. [DOI: 10.1007/s00775-013-1011-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 06/01/2013] [Indexed: 10/26/2022]
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31
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Ebadi A, Razzaghi-Asl N, Khoshneviszadeh M, Miri R. Comparative amino acid decomposition analysis of potent type I p38α inhibitors. ACTA ACUST UNITED AC 2013; 21:41. [PMID: 23714278 PMCID: PMC3680208 DOI: 10.1186/2008-2231-21-41] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 05/25/2013] [Indexed: 12/21/2022]
Abstract
Background and purpose of the study p38α is a member of mitogen-activated protein kinases (MAPK) considered as a prominent target in development of anti-inflammatory agents. Any abnormality in the phosphorylation process leads to the different human diseases such as cancer, diabetes and inflammatory diseases. Several small molecule p38α inhibitors have been developed up to now. In this regard, structural elucidation of p38 inhibitors needs to be done enabling us in rational lead development strategies. Methods Various interactions of three potent inhibitors with p38α active site have been evaluated in terms of binding energies and bond lengths via density function theory and MD simulations. Results Our comparative study showed that both ab initio and MD simulation led to the relatively similar results in pharmacophore discrimination of p38α inhibitors. Conclusion The results of the present study may find their usefulness in pharmacophore based modification of p38α inhibitors.
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Affiliation(s)
- Ahmad Ebadi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, PO Box 3288-71345, Shiraz, Iran.
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32
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Lehnert N, Scheidt WR, Wolf MW. Structure and Bonding in Heme–Nitrosyl Complexes and Implications for Biology. NITROSYL COMPLEXES IN INORGANIC CHEMISTRY, BIOCHEMISTRY AND MEDICINE II 2013. [DOI: 10.1007/430_2013_92] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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