1
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Gong Z, Wang L, Xu Y, Xie D, Qi X, Nam W, Guo M. Enhanced Reactivities of Iron(IV)-Oxo Porphyrin Species in Oxidation Reactions Promoted by Intramolecular Hydrogen-Bonding. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2310333. [PMID: 38477431 PMCID: PMC11109629 DOI: 10.1002/advs.202310333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/19/2024] [Indexed: 03/14/2024]
Abstract
High-valent iron-oxo species are one of the common intermediates in both biological and biomimetic catalytic oxidation reactions. Recently, hydrogen-bonding (H-bonding) has been proved to be critical in determining the selectivity and reactivity. However, few examples have been established for mechanistic insights into the H-bonding effect. Moreover, intramolecular H-bonding effect on both C-H activation and oxygen atom transfer (OAT) reactions in synthetic porphyrin model system has not been investigated yet. In this study, a series of heme-containing iron(IV)-oxo porphyrin species with or without intramolecular H-bonding are synthesized and characterized. Kinetic studies revealed that intramolecular H-bonding can significantly enhance the reactivity of iron(IV)-oxo species in OAT, C-H activation, and electron-transfer reactions. This unprecedented unified H-bonding effect is elucidated by theoretical calculations, which showed that intramolecular H-bonding interactions lower the energy of the anti-bonding orbital of iron(IV)-oxo porphyrin species, resulting in the enhanced reactivities in oxidation reactions irrespective of the reaction type. To the best of the knowledge, this is the first extensive investigation on the intramolecular H-bonding effect in heme system. The results show that H-bonding interactions have a unified effect with iron(IV)-oxo porphyrin species in all three investigated reactions.
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Affiliation(s)
- Zhe Gong
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Liwei Wang
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Yiran Xu
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Duanfeng Xie
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Xiaotian Qi
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Wonwoo Nam
- Department of Chemistry and Nano ScienceEwha Womans UniversitySeoul03760South Korea
| | - Mian Guo
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
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2
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Ansari M, Bhattacharjee S, Pantazis DA. Correlating Structure with Spectroscopy in Ascorbate Peroxidase Compound II. J Am Chem Soc 2024; 146:9640-9656. [PMID: 38530124 PMCID: PMC11009960 DOI: 10.1021/jacs.3c13169] [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] [Received: 11/23/2023] [Revised: 03/15/2024] [Accepted: 03/15/2024] [Indexed: 03/27/2024]
Abstract
Structural and spectroscopic investigations of compound II in ascorbate peroxidase (APX) have yielded conflicting conclusions regarding the protonation state of the crucial Fe(IV) intermediate. Neutron diffraction and crystallographic data support an iron(IV)-hydroxo formulation, whereas Mössbauer, X-ray absorption (XAS), and nuclear resonance vibrational spectroscopy (NRVS) studies appear consistent with an iron(IV)-oxo species. Here we examine APX with spectroscopy-oriented QM/MM calculations and extensive exploration of the conformational space for both possible formulations of compound II. We establish that irrespective of variations in the orientation of a vicinal arginine residue and potential reorganization of proximal water molecules and hydrogen bonding, the Fe-O distances for the oxo and hydroxo forms consistently fall within distinct, narrow, and nonoverlapping ranges. The accuracy of geometric parameters is validated by coupled-cluster calculations with the domain-based local pair natural orbital approach, DLPNO-CCSD(T). QM/MM calculations of spectroscopic properties are conducted for all structural variants, encompassing Mössbauer, optical, X-ray absorption, and X-ray emission spectroscopies and NRVS. All spectroscopic observations can be assigned uniquely to an Fe(IV)═O form. A terminal hydroxy group cannot be reconciled with the spectroscopic data. Under no conditions can the Fe(IV)═O distance be sufficiently elongated to approach the crystallographically reported Fe-O distance. The latter is consistent only with a hydroxo species, either Fe(IV) or Fe(III). Our findings strongly support the Fe(IV)═O formulation of APX-II and highlight unresolved discrepancies in the nature of samples used across different experimental studies.
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Affiliation(s)
- Mursaleem Ansari
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz
1, Mülheim an der Ruhr 45470, Germany
| | - Sinjini Bhattacharjee
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz
1, Mülheim an der Ruhr 45470, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für
Kohlenforschung, Kaiser-Wilhelm-Platz
1, Mülheim an der Ruhr 45470, Germany
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3
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Hou Z, Li Y, Zheng M, Liu X, Zhang Q, Wang W. Regioselective oxidation of heterocyclic aromatic hydrocarbons catalyzed by cytochrome P450: A case study of carbazole. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 258:114964. [PMID: 37121081 DOI: 10.1016/j.ecoenv.2023.114964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/11/2023] [Accepted: 04/26/2023] [Indexed: 05/22/2023]
Abstract
Recently there are increasing interests in accurately evaluating the health effects of heterocyclic PAHs. However, the activation mechanism and possible metabolites of heterocyclic PAHs catalyzed by human CYP1A1 is still elusive to a great extent. Here, leveraged to high level QM/MM calculations, the corresponding activation pathways of a representative heterocyclic PAHs, carbazole, were systematically explored. The first stage is electrophilic addition or hydrogen abstraction from N-H group. Electrophilic addition was evidenced to be more feasible and regioselectivity at C3 and C4 sites were identified. Correlations between energy barriers and key structural/electrostatic parameters reveal that O-Cα distance and Fe-O-Cα angle are the main origin for the catalytic regioselectivity. Electrophilic addition was determined as the rate-determining step and the subsequent possible reactions include epoxidation, NIH shift (the hydrogen migration from the site of hydroxylation to the adjacent carbon) and proton shuttle. The corresponding products are epoxides, ketones and hydroxylated carbazoles, respectively. The main metabolites (hydroxylated carbazoles) are estimated to be more toxic than carbazole. The regioselectivity of carbazole activated by CYP1A1 is different from the environmental processes (gas and aqueous phase). Collectively, these results will inform the in-depth understanding the metabolic processes of heterocyclic PAHs and aid the accurate evaluation of their health effects.
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Affiliation(s)
- Zexi Hou
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Yanwei Li
- Environment Research Institute, Shandong University, Qingdao 266237, PR China; Shenzhen Research Institute, Shandong University, Shenzhen 518057, PR China.
| | - Mingna Zheng
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Xinning Liu
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
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4
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Yuan F, Su B, Yu Y, Wang J. Study and design of amino acid-based radical enzymes using unnatural amino acids. RSC Chem Biol 2023; 4:431-446. [PMID: 37292061 PMCID: PMC10246556 DOI: 10.1039/d2cb00250g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 05/17/2023] [Indexed: 06/10/2023] Open
Abstract
Radical enzymes harness the power of reactive radical species by placing them in a protein scaffold, and they are capable of catalysing many important reactions. New native radical enzymes, especially those with amino acid-based radicals, in the category of non-heme iron enzymes (including ribonucleotide reductases), heme enzymes, copper enzymes, and FAD-radical enzymes have been discovered and characterized. We discussed recent research efforts to discover new native amino acid-based radical enzymes, and to study the roles of radicals in processes such as enzyme catalysis and electron transfer. Furthermore, design of radical enzymes in a small and simple scaffold not only allows us to study the radical in a well-controlled system and test our understanding of the native enzymes, but also allows us to create powerful enzymes. In the study and design of amino acid-based radical enzymes, the use of unnatural amino acids allows precise control of pKa values and reduction potentials of the residue, as well as probing the location of the radical through spectroscopic methods, making it a powerful research tool. Our understanding of amino acid-based radical enzymes will allow us to tailor them to create powerful catalysts and better therapeutics.
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Affiliation(s)
- Feiyan Yuan
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Binbin Su
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Yang Yu
- Institute of Biochemical Engineering, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, Ministry of Industry and Information Technology, School of Chemistry and Chemical Engineering, Beijing Institute of Technology Beijing 102488 China
| | - Jiangyun Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences Beijing 100101 China
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5
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Xiong J, Liu Q, Lavina B, Hu MY, Zhao J, Alp EE, Deng L, Ye S, Guo Y. Spin polarization assisted facile C-H activation by an S = 1 iron(iv)-bisimido complex: a comprehensive spectroscopic and theoretical investigation. Chem Sci 2023; 14:2808-2820. [PMID: 36937578 PMCID: PMC10016330 DOI: 10.1039/d2sc06273a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
High valent iron terminal imido species (Fe[double bond, length as m-dash]NR) have been shown to be key reactive intermediates in C-H functionalization. However, the detailed structure-reactivity relationship in Fe[double bond, length as m-dash]NR species derived from studies of structurally well-characterized high-valent Fe[double bond, length as m-dash]NR complexes are still scarce, and the impact of imido N-substituents (electron-donating vs. electron-withdrawing) on their electronic structures and reactivities has not been thoroughly explored. In this study, we report spectroscopic and computational studies on a rare S = 1 iron(iv)-bisimido complex featuring trifluoromethyl groups on the imido N-substituents, [(IPr)Fe(NC(CF3)2Ph)2] (2), and two closely related S = 0 congeners bearing alkyl and aryl substituents, [(IPr)Fe(NC(CMe3)2Ph)2] (3) and [(IPr)Fe(NDipp)2] (1), respectively. Compared with 1 and 3, 2 exhibits a decreased Fe[double bond, length as m-dash]NR bond covalency due to the electron-withdrawing and the steric effect of the N-substituents, which further leads to a pseudo doubly degenerate ground electronic structure and spin polarization induced β spin density on the imido nitrogens. This unique electronic structure, which differs from those of the well-studied Fe(iv)-oxido complexes and many previously reported Fe(iv)-imido complexes, provides both kinetic and thermodynamic advantages for facile C-H activation, compared to the S = 0 counterparts.
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Affiliation(s)
- Jin Xiong
- Department of Chemistry, Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA
| | - Qing Liu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 P. R. China
| | - Barbara Lavina
- Advanced Photon Source, Argonne National Laboratory Argonne Illinois 60439 USA
- Center for Advanced Radiation Sources, University of Chicago Chicago Illinois 60439 USA
| | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory Argonne Illinois 60439 USA
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory Argonne Illinois 60439 USA
| | - Esen E Alp
- Advanced Photon Source, Argonne National Laboratory Argonne Illinois 60439 USA
| | - Liang Deng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 P. R. China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 P. R. China
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA
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6
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Gable JA, Poulos TL, Follmer AH. Cooperative Substrate Binding Controls Catalysis in Bacterial Cytochrome P450terp (CYP108A1). J Am Chem Soc 2023; 145:10.1021/jacs.2c12388. [PMID: 36779970 PMCID: PMC10576961 DOI: 10.1021/jacs.2c12388] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Despite being one of the most well-studied aspects of cytochrome P450 chemistry, important questions remain regarding the nature and ubiquity of allosteric regulation of catalysis. The crystal structure of a bacterial P450, P450terp, in the presence of substrate reveals two binding sites, one above the heme in position for regioselective hydroxylation and another in the substrate access channel. Unlike many bacterial P450s, P450terp does not exhibit an open to closed conformational change when substrate binds; instead, P450terp uses the second substrate molecule to hold the first substrate molecule in position for catalysis. Spectral titrations clearly show that substrate binding to P450terp is cooperative with a Hill coefficient of 1.4 and is supported by isothermal titration calorimetry. The importance of the allosteric site was explored by a series of mutations that weaken the second site and that help hold the first substrate in position for proper catalysis. We further measured the coupling efficiency of both the wild-type (WT) enzyme and the mutant enzymes. While the WT enzyme exhibits 97% efficiency, each of the variants showed lower catalytic efficiency. Additionally, the variants show decreased spin shifts upon binding of substrate. These results are the first clear example of positive homotropic allostery in a class 1 bacterial P450 with its natural substrate. Combined with our recent results from P450cam showing complex substrate allostery and conformational dynamics, our present study with P450terp indicates that bacterial P450s may not be as simple as once thought and share complex substrate binding properties usually associated with only mammalian P450s.
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Affiliation(s)
- Jessica A Gable
- Departments of Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Thomas L Poulos
- Departments of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697-3900, United States
- Departments of Pharmaceutical Sciences, University of California, Irvine, Irvine, California 92697-3900, United States
- Departments of Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Alec H Follmer
- Departments of Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
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7
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Effect of Brшnsted Acid on the Reactivity and Selectivity of the Oxoiron(V) Intermediates in C-H and C=C Oxidation Reactions. Catalysts 2022. [DOI: 10.3390/catal12090949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The effect of HClO4 on the reactivity and selectivity of the catalyst systems 1,2/H2O2/AcOH, based on nonheme iron complexes of the PDP families, [(Me2OMePDP)FeIII(μ-OH)2FeIII(MeOMe2PDP)](OTf)4 (1) and [(NMe2PDP)FeIII(μ-OH)2FeIII(NMe2PDP](OTf)4 (2), toward oxidation of benzylideneacetone (bna), adamantane (ada), and (3aR)-(+)-sclareolide (S) has been studied. Adding HClO4 (2–10 equiv. vs. Fe) has been found to result in the simultaneous improvement of the observed catalytic efficiency (i.e., product yields) and the oxidation regio- or enantioselectivity. At the same time, HClO4 causes a threefold increase of the second-order rate constant for the reaction of the key oxygen-transferring intermediate [(Me2OMePDP)FeV=O(OAc)]2+ (1a), with cyclohexane at −70 °C. The effect of strong Brønsted acid on the catalytic reactivity is discussed in terms of the reversible protonation of the Fe=O moiety of the parent perferryl intermediates.
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8
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Abstract
The Gouterman four-orbital model conceptualizes porphyrin UV-visible spectra as dominated by four frontier molecular orbitals-two nearly degenerate HOMOs and two exactly degenerate LUMOS under D 4h symmetry. These are well separated from all the other molecular orbitals, and normal spectra involve transitions among these MOs. Unusual spectra occur when additional orbitals appear in this energy range, typically as a consequence of the central coordinated atom. For example, metals with empty d orbitals in a suitable energy range may lead to charge transfer from porphyrin (ligand) to metal, that is, so-called LMCT transitions. Metals with filled p or d orbitals may lead to charge transfer from metal to porphyrin, MLCT transitions. These cases lead to additional peaks and/or significant redshifts in the spectra and were classified as hyperporphyrins by Gouterman. Cases in which spectra are blueshifted were classified as hypsoporphyrins; they are common for relatively electronegative late transition metal porphyrins. Many of the same principles apply to porphyrin analogues, especially corroles. In this Perspective, we focus on two newer classes of hyperporphyrins: one reflecting substituent effects in protonated or deprotonated free-base tetraphenyporphyrins and the other reflecting "noninnocent" interactions between central metal ions and corroles. Hyperporphyrin effects on spectra can be dramatic, yet they can be generated by relatively simple changes and subtle structural variations, such as acid-base reactions or the selection of a central metal ion. These concepts suggest strategies for engineering porphyrin or porphyrinoid dyes for specific applications, especially those requiring far-red or near-infrared absorption or emission.
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Affiliation(s)
- Carl C. Wamser
- Department
of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Abhik Ghosh
- Department
of Chemistry and Arctic Center for Sustainable Energy, UiT − The Arctic University of Norway, N-9037 Tromsø, Norway
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9
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Poulos TL, Follmer AH. Updating the Paradigm: Redox Partner Binding and Conformational Dynamics in Cytochromes P450. Acc Chem Res 2022; 55:373-380. [PMID: 34965086 PMCID: PMC8959394 DOI: 10.1021/acs.accounts.1c00632] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This Account summarizes recent findings centered on the role that redox partner binding, allostery, and conformational dynamics plays in cytochrome P450 proton coupled electron transfer. P450s are one of Nature's largest enzyme families and it is not uncommon to find a P450 wherever substrate oxidation is required in the formation of essential molecules critical to the life of the organism or in xenobiotic detoxification. P450s can operate on a remarkably large range of substrates from the very small to the very large, yet the overall P450 three-dimensional structure is conserved. Given this conservation of structure, it is generally assumed that the basic catalytic mechanism is conserved. In nearly all P450s, the O2 O-O bond must be cleaved heterolytically enabling one oxygen atom, the distal oxygen, to depart as water and leave behind a heme iron-linked O atom as the powerful oxidant that is used to activate the nearby substrate. For this process to proceed efficiently, externally supplied electrons and protons are required. Two protons must be added to the departing O atom while an electron is transferred from a redox partner that typically contains either a Fe2S2 or FMN redox center. The paradigm P450 used to unravel the details of these mechanisms has been the bacterial CYP101A1 or P450cam. P450cam is specific for its own Fe2S2 redox partner, putidaredoxin or Pdx, and it has long been postulated that Pdx plays an effector/allosteric role by possibly switching P450cam to an active conformation. Crystal structures, spectroscopic data, and direct binding experiments of the P450cam-Pdx complex provide some answers. Pdx shifts the conformation of P450cam to a more open state, a transition that is postulated to trigger the proton relay network required for O2 activation. An essential part of this proton relay network is a highly conserved Asp (sometimes Glu) that is known to be critical for activity in a number of P450s. How this Asp and proton delivery networks are connected to redox partner binding is quite simple. In the closed state, this Asp is tied down by salt bridges, but these salt bridges are ruptured when Pdx binds, leaving the Asp free to serve its role in proton transfer. An alternative hypothesis suggests that a specific proton relay network is not really necessary. In this scenario, the Asp plays a structural role in the open/close transition and merely opening the active site access channel is sufficient to enable solvent protons in for O2 protonation. Experiments designed to test these various hypotheses have revealed some surprises in both P450cam and other bacterial P450s. Molecular dynamics and crystallography show that P450cam can undergo rather significant conformational gymnastics that result in a large restructuring of the active site requiring multiple cis/trans proline isomerizations. It also has been found that X-ray driven substrate hydroxylation is a useful tool for better understanding the role that the essential Asp and surrounding residues play in catalysis. Here we summarize these recent results which provide a much more dynamic picture of P450 catalysis.
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Affiliation(s)
- Thomas L. Poulos
- Departments of Molecular Biology & Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Alec H. Follmer
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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10
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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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11
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Karmalkar DG, Seo MS, Lee YM, Kim Y, Lee E, Sarangi R, Fukuzumi S, Nam W. Deeper Understanding of Mononuclear Manganese(IV)-Oxo Binding Brønsted and Lewis Acids and the Manganese(IV)-Hydroxide Complex. Inorg Chem 2021; 60:16996-17007. [PMID: 34705465 DOI: 10.1021/acs.inorgchem.1c02119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of Lewis acidic metal ions and Brønsted acid at the metal-oxo group of high-valent metal-oxo complexes enhances their reactivities significantly in oxidation reactions. However, such a binding of Lewis acids and proton at the metal-oxo group has been questioned in several cases and remains to be clarified. Herein, we report the synthesis, characterization, and reactivity studies of a mononuclear manganese(IV)-oxo complex binding triflic acid, {[(dpaq)MnIV(O)]-HOTf}+ (1-HOTf). First, 1-HOTf was synthesized and characterized using various spectroscopic techniques, including resonance Raman (rRaman) and X-ray absorption spectroscopy/extended X-ray absorption fine structure. In particular, in rRaman experiments, we observed a linear correlation between the Mn-O stretching frequencies of 1-HOTf (e.g., νMn-O at ∼793 cm-1) and 1-Mn+ (Mn+ = Ca2+, Zn2+, Lu3+, Al3+, or Sc3+) and the Lewis acidities of H+ and Mn+ ions, suggesting that H+ and Mn+ bind at the metal-oxo moiety of [(dpaq)MnIV(O)]+. Interestingly, a single-crystal structure of 1-HOTf was obtained by X-ray diffraction analysis, but the structure was not an expected Mn(IV)-oxo complex but a Mn(IV)-hydroxide complex, [(dpaq)MnIV(OH)](OTf)2 (4), with a Mn-O bond distance of 1.8043(19) Å and a Mn-O stretch at 660 cm-1. More interestingly, 4 reverted to 1-HOTf upon dissolution, demonstrating that 1-HOTf and 4 are interconvertible depending on the physical states, such as 1-HOTf in solution and 4 in isolated solid. The reactivity of 1-HOTf was investigated in hydrogen atom transfer (HAT) and oxygen atom transfer (OAT) reactions and then compared with those of 1-Mn+ complexes; an interesting correlation between the Mn-O stretching frequencies of 1-HOTf and 1-Mn+ and their reactivities in the OAT and HAT reactions is reported for the first time in this study.
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Affiliation(s)
- Deepika G Karmalkar
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Youngsuk Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
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12
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Guo M, Zhang J, Zhang L, Lee YM, Fukuzumi S, Nam W. Enthalpy-Entropy Compensation Effect in Oxidation Reactions by Manganese(IV)-Oxo Porphyrins and Nonheme Iron(IV)-Oxo Models. J Am Chem Soc 2021; 143:18559-18570. [PMID: 34723505 DOI: 10.1021/jacs.1c08198] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
"Enthalpy-Entropy Compensation Effect" (EECE) is ubiquitous in chemical reactions; however, such an EECE has been rarely explored in biomimetic oxidation reactions. In this study, six manganese(IV)-oxo complexes bearing electron-rich and -deficient porphyrins are synthesized and investigated in various oxidation reactions, such as hydrogen atom transfer (HAT), oxygen atom transfer (OAT), and electron-transfer (ET) reactions. First, all of the six Mn(IV)-oxo porphyrins are highly reactive in the HAT, OAT, and ET reactions. Interestingly, we have observed a reversed reactivity in the HAT and OAT reactions by the electron-rich and -deficient Mn(IV)-oxo porphyrins, depending on reaction temperatures, but not in the ET reactions; the electron-rich Mn(IV)-oxo porphyrins are more reactive than the electron-deficient Mn(IV)-oxo porphyrins at high temperature (e.g., 0 °C), whereas at low temperature (e.g., -60 °C), the electron-deficient Mn(IV)-oxo porphyrins are more reactive than the electron-rich Mn(IV)-oxo porphyrins. Such a reversed reactivity between the electron-rich and -deficient Mn(IV)-oxo porphyrins depending on reaction temperatures is rationalized with EECE; that is, the lower is the activation enthalpy, the more negative is the activation entropy, and vice versa. Interestingly, a unified linear correlation between the activation enthalpies and the activation entropies is observed in the HAT and OAT reactions of the Mn(IV)-oxo porphyrins. Moreover, from the previously reported HAT reactions of nonheme Fe(IV)-oxo complexes, a linear correlation between the activation enthalpies and the activation entropies is also observed. To the best of our knowledge, we report the first detailed mechanistic study of EECE in the oxidation reactions by synthetic high-valent metal-oxo complexes.
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Affiliation(s)
- Mian Guo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China
| | - Jisheng Zhang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Lina Zhang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,Faculty of Science and Engineering, Meijo University, Nagoya, Aichi 468-8502, Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, PR China
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13
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Jesse KA, Anferov SW, Collins KA, Valdez-Moreira JA, Czaikowski ME, Filatov AS, Anderson JS. Direct Aerobic Generation of a Ferric Hydroperoxo Intermediate Via a Preorganized Secondary Coordination Sphere. J Am Chem Soc 2021; 143:18121-18130. [PMID: 34698493 PMCID: PMC8569801 DOI: 10.1021/jacs.1c06911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Indexed: 01/19/2023]
Abstract
Enzymes exert control over the reactivity of metal centers with precise tuning of the secondary coordination sphere of active sites. One particularly elegant illustration of this principle is in the controlled delivery of proton and electron equivalents in order to activate abundant but kinetically inert oxidants such as O2 for oxidative chemistry. Chemists have drawn inspiration from biology in designing molecular systems where the secondary coordination sphere can shuttle protons or electrons to substrates. However, a biomimetic activation of O2 requires the transfer of both protons and electrons, and molecular systems where ancillary ligands are designed to provide both of these equivalents are comparatively rare. Here, we report the use of a dihydrazonopyrrole (DHP) ligand complexed to Fe to perform exactly such a biomimetic activation of O2. In the presence of O2, this complex directly generates a high spin Fe(III)-hydroperoxo intermediate which features a DHP• ligand radical via ligand-based transfer of an H atom. This system displays oxidative reactivity and ultimately releases hydrogen peroxide, providing insight on how secondary coordination sphere interactions influence the evolution of oxidizing intermediates in Fe-mediated aerobic oxidations.
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Affiliation(s)
- Kate A. Jesse
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Sophie W. Anferov
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Kelsey A. Collins
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | | | - Maia E. Czaikowski
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Alexander S. Filatov
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S. Anderson
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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14
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A new regime of heme-dependent aromatic oxygenase superfamily. Proc Natl Acad Sci U S A 2021; 118:2106561118. [PMID: 34667125 DOI: 10.1073/pnas.2106561118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2021] [Indexed: 12/14/2022] Open
Abstract
Two histidine-ligated heme-dependent monooxygenase proteins, TyrH and SfmD, have recently been found to resemble enzymes from the dioxygenase superfamily currently named after tryptophan 2,3-dioxygenase (TDO), that is, the TDO superfamily. These latest findings prompted us to revisit the structure and function of the superfamily. The enzymes in this superfamily share a similar core architecture and a histidine-ligated heme. Their primary functions are to promote O-atom transfer to an aromatic metabolite. TDO and indoleamine 2,3-dioxygenase (IDO), the founding members, promote dioxygenation through a two-step monooxygenation pathway. However, the new members of the superfamily, including PrnB, SfmD, TyrH, and MarE, expand its boundaries and mediate monooxygenation on a broader set of aromatic substrates. We found that the enlarged superfamily contains eight clades of proteins. Overall, this protein group is a more sizeable, structure-based, histidine-ligated heme-dependent, and functionally diverse superfamily for aromatics oxidation. The concept of TDO superfamily or heme-dependent dioxygenase superfamily is no longer appropriate for defining this growing superfamily. Hence, there is a pressing need to redefine it as a heme-dependent aromatic oxygenase (HDAO) superfamily. The revised concept puts HDAO in the context of thiol-ligated heme-based enzymes alongside cytochrome P450 and peroxygenase. It will update what we understand about the choice of heme axial ligand. Hemoproteins may not be as stringent about the type of axial ligand for oxygenation, although thiolate-ligated hemes (P450s and peroxygenases) more frequently catalyze oxygenation reactions. Histidine-ligated hemes found in HDAO enzymes can likewise mediate oxygenation when confronted with a proper substrate.
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15
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Ekanayake DM, Pham D, Probst AL, Miller JR, Popescu CV, Fiedler AT. Electronic structures and spectroscopic signatures of diiron intermediates generated by O 2 activation of nonheme iron(II)-thiolate complexes. Dalton Trans 2021; 50:14432-14443. [PMID: 34570147 PMCID: PMC8721859 DOI: 10.1039/d1dt02286e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The activation of O2 at thiolate-ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron-thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O2 to catalyze tandem S-C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron-thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB and OvoA (Dalton Trans. 2020, 49, 17745-17757). These models feature monodentate thiolate ligands and tripodal N4 ligands with mixed pyridyl/imidazolyl donors. Here, we describe the reactivity of 1 and 2 with O2 at low temperatures to give metastable intermediates (3 and 4, respectively). Characterization with multiple spectroscopic techniques (UV-vis absorption, NMR, variable-field and -temperature Mössbauer, and resonance Raman) revealed that these intermediates are thiolate-ligated iron(III) dimers with a bridging oxo ligand derived from the four-electron reduction of O2. Structural models of 3 and 4 consistent with the experimental data were generated via density functional theory (DFT) calculations. The combined experimental and computational results illuminate the geometric and electronic origins of the unique spectral features of diiron(III)-μ-oxo complexes with thiolate ligands, and the spectroscopic signatures of 3 and 4 are compared to those of closely-related diiron(III)-μ-peroxo species. Collectively, these results will assist in the identification of intermediates that appear on the O2 reaction landscapes of iron-thiolate species in both biological and synthetic environments.
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Affiliation(s)
| | - Dao Pham
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Andrew L Probst
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Joshua R Miller
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, USA
| | - Codrina V Popescu
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, USA.
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16
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Abstract
[Figure: see text].
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Affiliation(s)
- Lu Cheng
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biofunctional Materials, Jiangsu Key Laboratory of New Power Batteries, and Key Laboratory of Applied Photochemistry, Nanjing Normal University, Nanjing 210023, China.,School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Huihui Wang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biofunctional Materials, Jiangsu Key Laboratory of New Power Batteries, and Key Laboratory of Applied Photochemistry, Nanjing Normal University, Nanjing 210023, China.,School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Hengrui Cai
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biofunctional Materials, Jiangsu Key Laboratory of New Power Batteries, and Key Laboratory of Applied Photochemistry, Nanjing Normal University, Nanjing 210023, China.,School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Jie Zhang
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Xu Gong
- School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Wei Han
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biofunctional Materials, Jiangsu Key Laboratory of New Power Batteries, and Key Laboratory of Applied Photochemistry, Nanjing Normal University, Nanjing 210023, China.,School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
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17
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Ledray AP, Mittra K, Green MT. NRVS investigation of ascorbate peroxidase compound II: Observation of Iron(IV)oxo stretching. J Inorg Biochem 2021; 224:111548. [PMID: 34481347 DOI: 10.1016/j.jinorgbio.2021.111548] [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] [Received: 04/23/2021] [Revised: 07/07/2021] [Accepted: 07/13/2021] [Indexed: 11/18/2022]
Abstract
The protonation state of ascorbate peroxidase compound II (APX-II) has been a subject of debate. A combined X-ray/neutron crystallographic study reported that APX-II is best described as an iron(IV)hydroxide species with an FeO distance of 1.88 Å (Kwon, et al. Nat Commun2016, 7, 13,445), while X-ray absorption spectroscopy (XAS) experiments (utilizing extended X-ray absorption fine structure (EXAFS) and pre-edge analyses) indicate APX-II is an authentic iron(IV)oxo species with an FeO distance 1.68 Å (Ledray, et al. Journal of the American Chemical Society2020,142, 20,419). Previous debates concerning ferryl protonation states have been resolved through the application of Badger's rule, which correlates FeO bond distances with FeO vibrational frequencies. To obtain the required vibrational data, we have collected Nuclear Resonance Vibrational Spectroscopy (NRVS) data for APX-II. We observe a broad vibrational feature in the range associated with iron(IV)oxo stretching (700-800 cm-1). This feature appears to have two peaks at 732 cm-1 and 770 cm-1, corresponding to FeO distances of 1.69 and 1.67 Å, respectively. The broad vibrational envelope and the presence of multiple resonances could reflect a distribution of hydrogen bonding interactions within the active-site pocket.
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Affiliation(s)
- Aaron P Ledray
- Department of Chemistry, University of California, Irvine, CA 92697, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
| | - Kaustuv Mittra
- Department of Chemistry, University of California, Irvine, CA 92697, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
| | - Michael T Green
- Department of Chemistry, University of California, Irvine, CA 92697, USA; Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
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18
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Martin CP, Chen M, Martinez MF, Ding Y, Caranto JD. The Ferric-Superoxo Intermediate of the TxtE Nitration Pathway Resists Reduction, Facilitating Its Reaction with Nitric Oxide. Biochemistry 2021; 60:2436-2446. [PMID: 34319079 DOI: 10.1021/acs.biochem.1c00416] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
TxtE is a cytochrome P450 (CYP) homologue that mediates the nitric oxide (NO)-dependent direct nitration of l-tryptophan (Trp) to form 4-nitro-l-tryptophan (4-NO2-Trp). A recent report showed evidence that TxtE activity requires NO to react with a ferric-superoxo intermediate. Given this minimal mechanism, it is not clear how TxtE avoids Trp hydroxylation, a mechanism that also traverses the ferric-superoxo intermediate. To provide insight into canonical CYP intermediates that TxtE can access, electron coupling efficiencies to form 4-NO2-Trp under single- or limited-turnover conditions were measured and compared to steady-state efficiencies. As previously reported, Trp nitration by TxtE is supported by the engineered self-sufficient variant, TB14, as well as by reduced putidaredoxin. Ferrous (FeII) TxtE exhibits excellent electron coupling (70%), which is 50-fold higher than that observed under turnover conditions. In addition, two- or four-electron reduced TB14 exhibits electron coupling (∼6%) that is 2-fold higher than that of one-electron reduced TB14 (3%). The combined results suggest (1) autoxidation is the sole TxtE uncoupling pathway and (2) the TxtE ferric-superoxo intermediate cannot be reduced by these electron transfer partners. The latter conclusion is further supported by ultraviolet-visible absorption spectral time courses showing neither spectral nor kinetic evidence for reduction of the ferric-superoxo intermediate. We conclude that resistance of the ferric-superoxo intermediate to reduction is a key feature of TxtE that increases the lifetime of the intermediate and enables its reaction with NO and efficient nitration activity.
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Affiliation(s)
- Christopher P Martin
- Department of Chemistry, University of Central Florida, 4111 Libra Drive, Room 255, Orlando, Florida 32816, United States
| | - Manyun Chen
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, 1345 Center Drive, Room P6-27, Gainesville, Florida 32610, United States
| | - Maria F Martinez
- Department of Chemistry, University of Central Florida, 4111 Libra Drive, Room 255, Orlando, Florida 32816, United States
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, University of Florida, 1345 Center Drive, Room P6-27, Gainesville, Florida 32610, United States
| | - Jonathan D Caranto
- Department of Chemistry, University of Central Florida, 4111 Libra Drive, Room 255, Orlando, Florida 32816, United States
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19
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Sarmiento-Pavía PD, Sosa-Torres ME. Bioinorganic insights of the PQQ-dependent alcohol dehydrogenases. J Biol Inorg Chem 2021; 26:177-203. [PMID: 33606117 DOI: 10.1007/s00775-021-01852-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/07/2021] [Indexed: 12/19/2022]
Abstract
Among the several alcohol dehydrogenases, PQQ-dependent enzymes are mainly found in the α, β, and γ-proteobacteria. These proteins are classified into three main groups. Type I ADHs are localized in the periplasm and contain one Ca2+-PQQ moiety, being the methanol dehydrogenase (MDH) the most representative. In recent years, several lanthanide-dependent MDHs have been discovered exploding the understanding of the natural role of lanthanide ions. Type II ADHs are localized in the periplasm and possess one Ca2+-PQQ moiety and one heme c group. Finally, type III ADHs are complexes of two or three subunits localized in the cytoplasmic membrane and possess one Ca2+-PQQ moiety and four heme c groups, and in one of these proteins, an additional [2Fe-2S] cluster has been discovered recently. From the bioinorganic point of view, PQQ-dependent alcohol dehydrogenases have been revived recently mainly due to the discovery of the lanthanide-dependent enzymes. Here, we review the three types of PQQ-dependent ADHs with special focus on their structural features and electron transfer processes. The PQQ-Alcohol dehydrogenases are classified into three main groups. Type I and type II ADHs are located in the periplasm, while type III ADHs are in the cytoplasmic membrane. ADH-I have a Ca-PQQ or a Ln-PQQ, ADH-II a Ca-PQQ and one heme-c and ADH-III a Ca-PQQ and four hemes-c. This review focuses on their structural features and electron transfer processes.
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Affiliation(s)
- Pedro D Sarmiento-Pavía
- Facultad de Química, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, 04510, Ciudad de México, Mexico
| | - Martha E Sosa-Torres
- Facultad de Química, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, 04510, Ciudad de México, Mexico.
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20
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Li XX, Xue SS, Lu X, Seo MS, Lee YM, Kim WS, Cho KB, Nam W. Ligand Architecture Perturbation Influences the Reactivity of Nonheme Iron(V)-Oxo Tetraamido Macrocyclic Ligand Complexes: A Combined Experimental and Theoretical Study. Inorg Chem 2021; 60:4058-4067. [PMID: 33645218 DOI: 10.1021/acs.inorgchem.1c00110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron(V)-oxo complexes bearing negatively charged tetraamido macrocyclic ligands (TAMLs) have provided excellent opportunities to investigate the chemical properties and the mechanisms of oxidation reactions of mononuclear nonheme iron(V)-oxo intermediates. Herein, we report the differences in chemical properties and reactivities of two iron(V)-oxo TAML complexes differing by modification on the "Head" part of the TAML framework; one has a phenyl group at the "Head" part (1), whereas the other has four methyl groups replacing the phenyl ring (2). The reactivities of 1 and 2 in both C-H bond activation reactions, such as hydrogen atom transfer (HAT) of 1,4-cyclohexadiene, and oxygen atom transfer (OAT) reactions, such as the oxidation of thioanisole and its derivatives, were compared experimentally. Under identical reaction conditions, 1 showed much greater reactivity than 2, such as a 102-fold decrease in HAT and a 105-fold decrease in OAT by replacing the phenyl group (i.e., 1) with four methyl groups (i.e., 2). Then, density functional theory calculations were performed to rationalize the reactivity differences between 1 and 2. Computations reproduced the experimental findings well and revealed that the replacement of the phenyl group in 1 with four methyl groups in 2 not only increased the steric hindrance but also enlarged the energy gap between the electron-donating orbital and the electron-accepting orbital. These two factors, steric hindrance and the orbital energy gap, resulted in differences in the reduction potentials of 1 and 2 and their reactivities in oxidation reactions.
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Affiliation(s)
- Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Shan-Shan Xue
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Xiaoyan Lu
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Won-Suk Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Kyung-Bin Cho
- Department of Chemistry, Jeonbuk National University, Jeonju 54896, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
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21
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Hong YH, Jang Y, Ezhov R, Seo MS, Lee YM, Pandey B, Hong S, Pushkar Y, Fukuzumi S, Nam W. A Highly Reactive Chromium(V)–Oxo TAML Cation Radical Complex in Electron Transfer and Oxygen Atom Transfer Reactions. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00079] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Young Hyun Hong
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yuri Jang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Roman Ezhov
- Department of Physics and Astronomy, Purdue University 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Bhawana Pandey
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Seungwoo Hong
- Department of Chemistry, Sookmyung Women’s University, Seoul 04310, Korea
| | - Yulia Pushkar
- Department of Physics and Astronomy, Purdue University 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, People’s Republic of China
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22
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Paroxetine-Overview of the Molecular Mechanisms of Action. Int J Mol Sci 2021; 22:ijms22041662. [PMID: 33562229 PMCID: PMC7914979 DOI: 10.3390/ijms22041662] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/31/2021] [Accepted: 02/04/2021] [Indexed: 12/20/2022] Open
Abstract
In the 21st century and especially during a pandemic, the diagnosis and treatment of depression is an essential part of the daily practice of many family doctors. It mainly affects patients in the age category 15–44 years, regardless of gender. Anxiety disorders are often diagnosed in children and adolescents. Social phobias can account for up to 13% of these diagnoses. Social anxiety manifests itself in fear of negative social assessment and humiliation, which disrupts the quality of social functioning. Treatment of the above-mentioned disorders is based on psychotherapy and pharmacotherapy. Serious side effects or mortality from antidepressant drug overdose are currently rare. Recent studies indicate that paroxetine (ATC code: N06AB), belonging to the selective serotonin reuptake inhibitors, has promising therapeutic effects and is used off-label in children and adolescents. The purpose of this review is to describe the interaction of paroxetine with several molecular targets in various points of view including the basic chemical and pharmaceutical properties. The central point of the review is focused on the pharmacodynamic analysis based on the molecular mechanism of binding paroxetine to various therapeutic targets.
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23
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Roos G, Harvey JN. Histidine versus Cysteine-Bearing Heme-Dependent Halogen Peroxidases: Parallels and Differences for Cl - Oxidation. J Phys Chem B 2021; 125:74-85. [PMID: 33350832 DOI: 10.1021/acs.jpcb.0c09409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The homodimeric myeloperoxidase (MPO) features a histidine as a proximal ligand and a sulfonium linkage covalently attaching the heme porphyrin ring to the protein. MPO is able to catalyze Cl- oxidation with about the same efficiency as chloroperoxidase at pH 7.0. In this study, we seek to explore the parallels and differences between the histidine and cysteine heme-dependent halogen peroxidases. Transition states, reaction barriers, and relevant thermodynamic properties are calculated on protein models. Together with electronic structure calculations, it gives an overview of the reaction mechanisms and of the factors that determine the selectivity between one- and two-electron paths. Conclusions point to the innate oxidizing nature of MPO with the ester and sulfonium linkages hiking up the reactivity to enable chloride oxidation. The installation of a deprotonated imidazolate as a proximal ligand does not shift the equilibrium from one- to two-electron events without influencing the chemistry of the oxidation reaction.
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Affiliation(s)
- Goedele Roos
- UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, University of Lille, CNRS, UMR 8576, F-59000 Lille, France
| | - Jeremy N Harvey
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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24
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Zhang L, Lee YM, Guo M, Fukuzumi S, Nam W. Unprecedented Reactivities of Highly Reactive Manganese(III)-Iodosylarene Porphyrins in Oxidation Reactions. J Am Chem Soc 2020; 142:19879-19884. [PMID: 33186008 DOI: 10.1021/jacs.0c10159] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We report that Mn(III)-iodosylarene porphyrins, [MnIII(Porp)(sArIO)]+, are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, with unprecedented reactivities, such as a low kinetic isotope effect, a saturation behavior of reaction rates, and no electronic effect of porphyrin ligands on the reactivities of [MnIII(Porp)(sArIO)]+. In oxygen atom transfer (OAT) reactions, the sulfoxidation of para-X-substituted thioanisoles by [MnIII(Porp)(sArIO)]+ affords a very unusual behavior in the Hammett plot with the saturation behavior of reaction rates and no electronic effect of porphyrin ligands on reactivities. The reactivities and mechanisms of [MnIII(Porp)(sArIO)]+ are then compared with those of the corresponding MnIV(Porp)(O) complex. The present study reports the first example of highly reactive Mn(III)-iodosylarene porphyrins with unprecedented reactivities in C-H bond activation and OAT reactions.
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Affiliation(s)
- Lina Zhang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Mian Guo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
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25
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Ledray AP, Krest CM, Yosca TH, Mittra K, Green MT. Ascorbate Peroxidase Compound II Is an Iron(IV) Oxo Species. J Am Chem Soc 2020; 142:10.1021/jacs.0c09108. [PMID: 33170000 PMCID: PMC8107191 DOI: 10.1021/jacs.0c09108] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The protonation state of the iron(IV) oxo (or ferryl) form of ascorbate peroxidase compound II (APX-II) is a subject of debate. It has been reported that this intermediate is best described as an iron(IV) hydroxide species. Neutron diffraction data obtained from putative APX-II crystals indicate a protonated oxygenic ligand at 1.88 Å from the heme iron. This finding, if correct, would be unprecedented. A basic iron(IV) oxo species has yet to be spectroscopically observed in a histidine-ligated heme enzyme. The importance of ferryl basicity lies in its connection to our fundamental understanding of C-H bond activation. Basic ferryl species have been proposed to facilitate the oxidation of inert C-H bonds, reactions that are unknown for histidine-ligated hemes enzymes. To provide further insight into the protonation status of APX-II, we examined the intermediate using a combination of Mössbauer and X-ray absorption spectroscopies. Our data indicate that APX-II is an iron(IV) oxo species with an Fe-O bond distance of 1.68 Å, a K-edge pre-edge absorption of 18 units, and Mössbauer parameters of ΔEq = 1.65 mm/s and δ = 0.03 mm/s.
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Affiliation(s)
- Aaron P Ledray
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Courtney M Krest
- Roach & Associates, Limited Liability Company, Seymour, Wisconsin 54942, United States
| | - Timothy H Yosca
- Department of Chemistry, University of California, Irvine, California 92697, United States
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Kaustuv Mittra
- Department of Chemistry, University of California, Irvine, California 92697, United States
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Michael T Green
- Department of Chemistry, University of California, Irvine, California 92697, United States
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
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26
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Ansari M, Senthilnathan D, Rajaraman G. Deciphering the origin of million-fold reactivity observed for the open core diiron [HO-Fe III-O-Fe IV[double bond, length as m-dash]O] 2+ species towards C-H bond activation: role of spin-states, spin-coupling, and spin-cooperation. Chem Sci 2020; 11:10669-10687. [PMID: 33209248 PMCID: PMC7654192 DOI: 10.1039/d0sc02624g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/16/2020] [Indexed: 01/26/2023] Open
Abstract
High-valent metal-oxo species have been characterised as key intermediates in both heme and non-heme enzymes that are found to perform efficient aliphatic hydroxylation, epoxidation, halogenation, and dehydrogenation reactions. Several biomimetic model complexes have been synthesised over the years to mimic both the structure and function of metalloenzymes. The diamond-core [Fe2(μ-O)2] is one of the celebrated models in this context as this has been proposed as the catalytically active species in soluble methane monooxygenase enzymes (sMMO), which perform the challenging chemical conversion of methane to methanol at ease. In this context, a report of open core [HO(L)FeIII-O-FeIV(O)(L)]2+ (1) gains attention as this activates C-H bonds a million-fold faster compared to the diamond-core structure and has the dual catalytic ability to perform hydroxylation as well as desaturation with organic substrates. In this study, we have employed density functional methods to probe the origin of the very high reactivity observed for this complex and also to shed light on how this complex performs efficient hydroxylation and desaturation of alkanes. By modelling fifteen possible spin-states for 1 that could potentially participate in the reaction mechanism, our calculations reveal a doublet ground state for 1 arising from antiferromagnetic coupling between the quartet FeIV centre and the sextet FeIII centre, which regulates the reactivity of this species. The unusual stabilisation of the high-spin ground state for FeIV[double bond, length as m-dash]O is due to the strong overlap of with the orbital, reducing the antibonding interactions via spin-cooperation. The electronic structure features computed for 1 are consistent with experiments offering confidence in the methodology chosen. Further, we have probed various mechanistic pathways for the C-H bond activation as well as -OH rebound/desaturation of alkanes. An extremely small barrier height computed for the first hydrogen atom abstraction by the terminal FeIV[double bond, length as m-dash]O unit was found to be responsible for the million-fold activation observed in the experiments. The barrier height computed for -OH rebound by the FeIII-OH unit is also smaller suggesting a facile hydroxylation of organic substrates by 1. A strong spin-cooperation between the two iron centres also reduces the barrier for second hydrogen atom abstraction, thus making the desaturation pathway competitive. Both the spin-state as well as spin-coupling between the two metal centres play a crucial role in dictating the reactivity for species 1. By exploring various mechanistic pathways, our study unveils the fact that the bridged μ-oxo group is a poor electrophile for both C-H activation as well for -OH rebound. As more and more evidence is gathered in recent years for the open core geometry of sMMO enzymes, the idea of enhancing the reactivity via an open-core motif has far-reaching consequences.
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Affiliation(s)
- Mursaleem Ansari
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
| | - Dhurairajan Senthilnathan
- Center for Computational Chemistry , CRD , PRIST University , Vallam , Thanjavur , Tamilnadu 613403 , India
| | - Gopalan Rajaraman
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
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27
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Cummins DC, Alvarado JG, Zaragoza JPT, Effendy Mubarak MQ, Lin YT, de Visser SP, Goldberg DP. Hydroxyl Transfer to Carbon Radicals by Mn(OH) vs Fe(OH) Corrole Complexes. Inorg Chem 2020; 59:16053-16064. [PMID: 33047596 DOI: 10.1021/acs.inorgchem.0c02640] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The transfer of •OH from metal-hydroxo species to carbon radicals (R•) to give hydroxylated products (ROH) is a fundamental process in metal-mediated heme and nonheme C-H bond oxidations. This step, often referred to as the hydroxyl "rebound" step, is typically very fast, making direct study of this process challenging if not impossible. In this report, we describe the reactions of the synthetic models M(OH)(ttppc) (M = Fe (1), Mn (3); ttppc = 5,10,15-tris(2,4,6-triphenyl)phenyl corrolato3-) with a series of triphenylmethyl carbon radical (R•) derivatives ((4-X-C6H4)3C•; X = OMe, tBu, Ph, Cl, CN) to give the one-electron reduced MIII(ttppc) complexes and ROH products. Rate constants for 3 for the different radicals ranged from 11.4(1) to 58.4(2) M-1 s-1, as compared to those for 1, which fall between 0.74(2) and 357(4) M-1 s-1. Linear correlations for Hammett and Marcus plots for both Mn and Fe were observed, and the small magnitudes of the slopes for both correlations imply a concerted •OH transfer reaction for both metals. Eyring analyses of reactions for 1 and 3 with (4-X-C6H4)3C• (X = tBu, CN) also give good linear correlations, and a comparison of the resulting activation parameters highlight the importance of entropy in these •OH transfer reactions. Density functional theory calculations of the reaction profiles show a concerted process with one transition state for all radicals investigated and help to explain the electronic features of the OH rebound process.
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Affiliation(s)
- Daniel C Cummins
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jessica G Alvarado
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jan Paulo T Zaragoza
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Muhammad Qadri Effendy Mubarak
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Yen-Ting Lin
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Sam P de Visser
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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28
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Xue SS, Li XX, Lee YM, Seo MS, Kim Y, Yanagisawa S, Kubo M, Jeon YK, Kim WS, Sarangi R, Kim SH, Fukuzumi S, Nam W. Enhanced Redox Reactivity of a Nonheme Iron(V)-Oxo Complex Binding Proton. J Am Chem Soc 2020; 142:15305-15319. [PMID: 32786748 DOI: 10.1021/jacs.0c05108] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Acid effects on the chemical properties of metal-oxygen intermediates have attracted much attention recently, such as the enhanced reactivity of high-valent metal(IV)-oxo species by binding proton(s) or Lewis acidic metal ion(s) in redox reactions. Herein, we report for the first time the proton effects of an iron(V)-oxo complex bearing a negatively charged tetraamido macrocyclic ligand (TAML) in oxygen atom transfer (OAT) and electron-transfer (ET) reactions. First, we synthesized and characterized a mononuclear nonheme Fe(V)-oxo TAML complex (1) and its protonated iron(V)-oxo complexes binding two and three protons, which are denoted as 2 and 3, respectively. The protons were found to bind to the TAML ligand of the Fe(V)-oxo species based on spectroscopic characterization, such as resonance Raman, extended X-ray absorption fine structure (EXAFS), and electron paramagnetic resonance (EPR) measurements, along with density functional theory (DFT) calculations. The two-protons binding constant of 1 to produce 2 and the third protonation constant of 2 to produce 3 were determined to be 8.0(7) × 108 M-2 and 10(1) M-1, respectively. The reactivities of the proton-bound iron(V)-oxo complexes were investigated in OAT and ET reactions, showing a dramatic increase in the rate of sulfoxidation of thioanisole derivatives, such as 107 times increase in reactivity when the oxidation of p-CN-thioanisole by 1 was performed in the presence of HOTf (i.e., 200 mM). The one-electron reduction potential of 2 (Ered vs SCE = 0.97 V) was significantly shifted to the positive direction, compared to that of 1 (Ered vs SCE = 0.33 V). Upon further addition of a proton to a solution of 2, a more positive shift of the Ered value was observed with a slope of 47 mV/log([HOTf]). The sulfoxidation of thioanisole derivatives by 2 was shown to proceed via ET from thioanisoles to 2 or direct OAT from 2 to thioanisoles, depending on the ET driving force.
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Affiliation(s)
- Shan-Shan Xue
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yujeong Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,Western Seoul Center, Korea Basic Science Institute, Seoul 03759, Korea
| | - Sachiko Yanagisawa
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Minoru Kubo
- Graduate School of Life Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Young-Kyo Jeon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Won-Suk Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, California 94025, United States
| | - Sun Hee Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,Western Seoul Center, Korea Basic Science Institute, Seoul 03759, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
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29
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Forneris CC, Nguy AKL, Seyedsayamdost MR. Mapping and Exploiting the Promiscuity of OxyB toward the Biocatalytic Production of Vancomycin Aglycone Variants. ACS Catal 2020; 10:9287-9298. [PMID: 34422446 PMCID: PMC8378672 DOI: 10.1021/acscatal.0c01719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vancomycin is one of the most important clinical antibiotics in the fight against infectious disease. Its biological activity relies on three aromatic cross-links, which create a cup-shaped topology and allow tight binding to nascent peptidoglycan chains. The cytochrome P450 enzymes OxyB, OxyA, and OxyC have been shown to introduce these synthetically challenging aromatic linkages. The ability to utilize the P450 enzymes in a chemo-enzymatic scheme to generate vancomycin derivatives is appealing but requires a thorough understanding of their reactivities and mechanisms. Herein, we systematically explore the scope of OxyB biocatalysis and report installation of diverse diaryl ether and biaryl cross-links with varying macrocycle sizes and compositions, when the enzyme is presented with modified vancomycin precursor peptides. The structures of the resulting products were determined using one-dimensional/two-dimensional nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry (HR-MS), tandem HR-MS, and isotopic labeling, as well as ultraviolet-visible light absorption and fluorescence emission spectroscopies. An exploration of the biological activities of these alternative OxyB products surprisingly revealed antifungal properties. Taking advantage of the promiscuity of OxyB, we chemo-enzymatically generated a vancomycin aglycone variant containing an expanded macrocycle. Mechanistic implications for OxyB and future directions for creating vancomycin analogue libraries are discussed.
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Affiliation(s)
- Clarissa C Forneris
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Andy K L Nguy
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry and Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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30
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Hunt AP, Samanta S, Dent MR, Milbauer MW, Burstyn JN, Lehnert N. Model Complexes Elucidate the Role of the Proximal Hydrogen-Bonding Network in Cytochrome P450s. Inorg Chem 2020; 59:8034-8043. [DOI: 10.1021/acs.inorgchem.0c00245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew P. Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Subhra Samanta
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Matthew R. Dent
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Michael W. Milbauer
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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31
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Lu X, Li XX, Lee YM, Jang Y, Seo MS, Hong S, Cho KB, Fukuzumi S, Nam W. Electron-Transfer and Redox Reactivity of High-Valent Iron Imido and Oxo Complexes with the Formal Oxidation States of Five and Six. J Am Chem Soc 2020; 142:3891-3904. [DOI: 10.1021/jacs.9b11682] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Xiaoyan Lu
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yuri Jang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Seungwoo Hong
- Department of Chemistry, Sookmyung Women’s University, Seoul 04310, Korea
| | - Kyung-Bin Cho
- Department of Chemistry, Jeonbuk National University, Jeonju 54896, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- Graduate School of Science and Engineering, Meijo University, Nagoya, Aichi 468-8502, Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China
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32
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Lu X, Lee YM, Seo MS, Nam W. Proton-promoted disproportionation of iron(v)-imido TAML to iron(v)-imido TAML cation radical and iron(iv) TAML. Chem Commun (Camb) 2020; 56:11207-11210. [DOI: 10.1039/d0cc05145d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
An iron(v)-imido TAML complex is disproportionated to give an iron(v)-imido TAML cation radical and an iron(iv) TAML upon addition of acids.
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Affiliation(s)
- Xiaoyan Lu
- Department of Chemistry and Nano Science
- Ewha Womans University
- Seoul 03760
- Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science
- Ewha Womans University
- Seoul 03760
- Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science
- Ewha Womans University
- Seoul 03760
- Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science
- Ewha Womans University
- Seoul 03760
- Korea
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33
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Dent MR, Milbauer MW, Hunt AP, Aristov MM, Guzei IA, Lehnert N, Burstyn JN. Electron Paramagnetic Resonance Spectroscopy as a Probe of Hydrogen Bonding in Heme-Thiolate Proteins. Inorg Chem 2019; 58:16011-16027. [PMID: 31786931 PMCID: PMC11160398 DOI: 10.1021/acs.inorgchem.9b02506] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Despite utilizing a common cofactor binding motif, hemoproteins bearing a cysteine-derived thiolate ligand (heme-thiolate proteins) are involved in a diverse array of biological processes ranging from drug metabolism to transcriptional regulation. Though the origin of heme-thiolate functional divergence is not well understood, growing evidence suggests that the hydrogen bonding (H-bonding) environment surrounding the Fe-coordinating thiolate influences protein function. Outside of X-ray crystallography, few methods exist to characterize these critical H-bonding interactions. Electron paramagnetic resonance (EPR) spectra of heme-thiolate proteins bearing a six-coordinate, Fe(III) heme exhibit uniquely narrow low-spin (S = 1/2), rhombic signals, which are sensitive to changes in the heme-thiolate H-bonding environment. To establish a well-defined relationship between the magnitude of g-value dispersion in this unique EPR signal and the strength of the heme-thiolate H-bonding environment, we synthesized and characterized of a series of six-coordinate, aryl-thiolate-ligated Fe(III) porphyrin complexes bearing a tunable intramolecular H-bond. Spectroscopic investigation of these complexes revealed a direct correlation between H-bond strength and g-value dispersion in the rhombic EPR signal. Using density functional theory (DFT), we elucidated the electronic origins of the narrow, rhombic EPR signal in heme-thiolates, which arises from an Fe-S pπ-dπ bonding interaction. Computational analysis of the intramolecularly H-bonded heme-thiolate models revealed that H-bond donation to the coordinating thiolate reduces thiolate donor strength and weakens this Fe-S interaction, giving rise to larger g-value dispersion. By defining the relationship between heme-thiolate electronic structure and rhombic EPR signal, it is possible to compare thiolate donor strengths among heme-thiolate proteins through analysis of low-spin, Fe(III) EPR spectra. Thus, this study establishes EPR spectroscopy as a valuable tool for exploring how second coordination sphere effects influence heme-thiolate protein function.
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Affiliation(s)
- Matthew R. Dent
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Michael W. Milbauer
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Andrew P. Hunt
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Michael M. Aristov
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Ilia A. Guzei
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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34
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Li XX, Guo M, Qiu B, Cho KB, Sun W, Nam W. High-Spin Mn(V)-Oxo Intermediate in Nonheme Manganese Complex-Catalyzed Alkane Hydroxylation Reaction: Experimental and Theoretical Approach. Inorg Chem 2019; 58:14842-14852. [PMID: 31621303 DOI: 10.1021/acs.inorgchem.9b02543] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mononuclear nonheme manganese complexes are highly efficient catalysts in the catalytic oxidation of hydrocarbons by hydrogen peroxide in the presence of carboxylic acids. Although high-valent Mn(V)-oxo complexes have been proposed as the active oxidants that afford high regio-, stereo-, and enantioselectivities in the catalytic oxidation reactions, the importance of the spin state (e.g., S = 0 or 1) of the proposed Mn(V)-oxo species is an area that requires further study. In the present study, we have theoretically demonstrated that a mononuclear nonheme Mn(V)-oxo species with an S = 1 ground spin state is the active oxidant that effects the stereo- and enantioselective alkane hydroxylation reaction; it is noted that synthetic octahedral Mn(V)-oxo complexes, characterized spectroscopically and/or structurally, possess an S = 0 spin state and are sluggish oxidants. In an experimental approach, we have investigated the catalytic hydroxylation of alkanes by a mononuclear nonheme Mn(II) complex, [(S-PMB)MnII]2+, and H2O2 in the presence of carboxylic acids; alcohol is the major product with high stereo- and enantioselectivities. A synthetic Mn(IV)-oxo complex, [(S-PMB)MnIV(O)]2+, is inactive in C-H bond activation reactions, ruling out the Mn(IV)-oxo species as an active oxidant. DFT calculations have shown that a Mn(V)-oxo species with an S = 1 spin state, [(S-PMB)MnV(O)(OAc)]2+, is highly reactive and capable of oxygenating the C-H bond via oxygen rebound mechanism; we propose that the triplet spin state of the Mn(V)-oxo species results from the consequence of breaking the equatorial symmetry due to the binding of an equatorial oxygen from an acetate ligand. Thus, the present study reports that, different from the previously reported S = 0 Mn(V)-oxo species, Mn(V)-oxo species with a triplet ground spin state are highly reactive oxidants that are responsible for the regio-, stereo-, and enantioselectivities in the catalytic hydroxylation of alkanes by mononuclear nonheme manganese complexes and terminal oxidants.
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Affiliation(s)
- Xiao-Xi Li
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Mian Guo
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Bin Qiu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, and Suzhou Research Institute of LICP , Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000 , China
| | - Kyung-Bin Cho
- Department of Chemistry , Jeonbuk National University , Jeonju 54896 , Korea
| | - Wei Sun
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, and Suzhou Research Institute of LICP , Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000 , China
| | - Wonwoo Nam
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, and Suzhou Research Institute of LICP , Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000 , China
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35
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Karmalkar DG, Sankaralingam M, Seo MS, Ezhov R, Lee YM, Pushkar YN, Kim WS, Fukuzumi S, Nam W. A High-Valent Manganese(IV)-Oxo-Cerium(IV) Complex and Its Enhanced Oxidizing Reactivity. Angew Chem Int Ed Engl 2019; 58:16124-16129. [PMID: 31489757 DOI: 10.1002/anie.201910032] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Indexed: 12/20/2022]
Abstract
A mononuclear nonheme manganese(IV)-oxo complex binding the Ce4+ ion, [(dpaq)MnIV (O)]+ -Ce4+ (1-Ce4+ ), was synthesized by reacting [(dpaq)MnIII (OH)]+ (2) with cerium ammonium nitrate (CAN). 1-Ce4+ was characterized using various spectroscopic techniques, such as UV/Vis, EPR, CSI-MS, resonance Raman, XANES, and EXAFS, showing an Mn-O bond distance of 1.69 Å with a resonance Raman band at 675 cm-1 . Electron-transfer and oxygen atom transfer reactivities of 1-Ce4+ were found to be greater than those of MnIV (O) intermediates binding redox-inactive metal ions (1-Mn+ ). This study reports the first example of a redox-active Ce4+ ion-bound MnIV -oxo complex and its spectroscopic characterization and chemical properties.
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Affiliation(s)
- Deepika G Karmalkar
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | | | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | - Roman Ezhov
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN, 47907, USA
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | - Yulia N Pushkar
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN, 47907, USA
| | - Won-Suk Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.,Faculty of Science and Engineering, Meijo University, Nagoya, Aichi, 468-0073, Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.,School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
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36
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Karmalkar DG, Sankaralingam M, Seo MS, Ezhov R, Lee Y, Pushkar YN, Kim W, Fukuzumi S, Nam W. A High‐Valent Manganese(IV)–Oxo–Cerium(IV) Complex and Its Enhanced Oxidizing Reactivity. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Deepika G. Karmalkar
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
| | | | - Mi Sook Seo
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
| | - Roman Ezhov
- Department of Physics and Astronomy Purdue University 525 Northwestern Ave. West Lafayette IN 47907 USA
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
| | - Yulia N. Pushkar
- Department of Physics and Astronomy Purdue University 525 Northwestern Ave. West Lafayette IN 47907 USA
| | - Won‐Suk Kim
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
- Faculty of Science and Engineering Meijo University Nagoya Aichi 468-0073 Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 Korea
- School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
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37
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Ehudin MA, Quist DA, Karlin KD. Enhanced Rates of C-H Bond Cleavage by a Hydrogen-Bonded Synthetic Heme High-Valent Iron(IV) Oxo Complex. J Am Chem Soc 2019; 141:12558-12569. [PMID: 31318198 PMCID: PMC6734939 DOI: 10.1021/jacs.9b01253] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Secondary coordination sphere interactions are critical in facilitating the formation, stabilization, and enhanced reactivity of high-valent oxidants required for essential biochemical processes. Herein, we compare the C-H bond oxidizing capabilities of spectroscopically characterized synthetic heme iron(IV) oxo complexes, F8Cmpd-II (F8 = tetrakis(2,6-difluorophenyl)porphyrinate), and a 2,6-lutidinium triflate (LutH+) Lewis acid adduct involving ferryl O-atom hydrogen-bonding, F8Cmpd-II(LutH+). Second-order rate constants utilizing C-H and C-D substrates were obtained by UV-vis spectroscopic monitoring, while products were characterized and quantified by EPR spectroscopy and gas chromatography (GC). With xanthene, F8Cmpd-II(LutH+) reacts 40 times faster (k2 = 14.2 M-1 s-1; -90 °C) than does F8Cmpd-II, giving bixanthene plus xanthone and the heme product [F8FeIIIOH2]+. For substrates with greater C-H bond dissociation energies (BDEs) F8Cmpd-II(LutH+) reacts with the second order rate constants k2(9,10-dihydroanthracene; DHA) = 0.485 M-1 s-1 and k2(fluorene) = 0.102 M-1 s-1 (-90 °C); by contrast, F8Cmpd-II is unreactive toward these substrates. For xanthene vs xanthene-(d2), large, nonclassical deuterium kinetic isotope effects are roughly estimated for both F8Cmpd-II and F8Cmpd-II(LutH+). The deuterated H-bonded analog, F8Cmpd-II(LutD+), was also prepared; for the reaction with DHA, an inverse KIE (compared to F8Cmpd-II(LutH+)) was observed. This work originates/inaugurates experimental investigation of the reactivity of authentic H-bonded heme-based FeIV═O compounds, critically establishing the importance of oxo H-bonding (or protonation) in heme complexes and enzyme active sites.
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Affiliation(s)
- Melanie A. Ehudin
- 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
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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38
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Guo M, Seo MS, Lee YM, Fukuzumi S, Nam W. Highly Reactive Manganese(IV)-Oxo Porphyrins Showing Temperature-Dependent Reversed Electronic Effect in C-H Bond Activation Reactions. J Am Chem Soc 2019; 141:12187-12191. [PMID: 31337211 DOI: 10.1021/jacs.9b04496] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report that Mn(IV)-oxo porphyrin complexes, MnIV(O)(TMP) (1) and MnIV(O)(TDCPP) (2), are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, 1 with an electron-rich porphyrin is more reactive than 2 with an electron-deficient porphyrin at a high temperature (e.g., 0 °C). However, at a low temperature (e.g., -40 °C), the reactivity of 1 and 2 is reversed, showing that 2 is more reactive than 1. To the best of our knowledge, the present study reports the first example of highly reactive Mn(IV)-oxo porphyrins and their temperature-dependent reactivity in C-H bond activation reactions.
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Affiliation(s)
- Mian Guo
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,Faculty of Science and Engineering , Meijo University , Nagoya , Aichi 468-0073 , Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710119 , China
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39
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Wegeberg C, Browne WR, McKenzie CJ. cis Donor Influence on O–O Bond Lability in Iron(III) Hydroperoxo Complexes: Oxidation Catalysis and Ligand Transformation. Inorg Chem 2019; 58:8983-8994. [DOI: 10.1021/acs.inorgchem.9b00247] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christina Wegeberg
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Wesley R. Browne
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Christine J. McKenzie
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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40
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Mittra K, Green MT. Reduction Potentials of P450 Compounds I and II: Insight into the Thermodynamics of C-H Bond Activation. J Am Chem Soc 2019; 141:5504-5510. [PMID: 30892878 DOI: 10.1021/jacs.9b00242] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We present a mixed experimental/theoretical determination of the bond strengths and redox potentials that define the ground-state thermodynamics for C-H bond activation in cytochrome P450 catalysis. Using redox titrations with [Ir(IV)Cl6]2-, we have determined the compound II/ferric (or Fe(IV)OH/Fe(III)OH2) couple and its associated D(O-H)Ferric bond strength in CYP158. Knowledge of this potential as well as the compound II/ferric (or Fe(IV)O/Fe(III)OH) reduction potential in horseradish peroxidase and the two-electron compound I/ferric (or Fe(IV)O(Por•)/Fe(III)OH2(Por)) reduction potential in aromatic peroxidase has allowed us to gauge the accuracy of theoretically determined bond strengths. Using the restricted open shell (ROS) method as proposed by Wright and co-workers, we have obtained O-H bond strengths and associated redox potentials for charge-neutral H-atom reductions of these iron(IV)-hydroxo and -oxo porphyrin species that are within 1 kcal/mol of experimentally determined values, suggesting that the ROS method may provide accurate values for the P450-II O-H bond strength and P450-I reduction potential. The efforts detailed here indicate that the ground-state thermodynamics of C-H bond activation in P450 are best described as follows: E0'Comp-I = 1.22 V (at pH 7, vs NHE) with D(O-H)Comp-II = 95 kcal/mol and E0'Comp-II = 0.99 V (at pH 7, vs NHE) with D(O-H)Ferric = 90 kcal/mol.
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Affiliation(s)
- Kaustuv Mittra
- Department of Chemistry and Department of Molecular Biology and Biochemistry , University of California , Irvine , California 92697 , United States
| | - Michael T Green
- Department of Chemistry and Department of Molecular Biology and Biochemistry , University of California , Irvine , California 92697 , United States
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41
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Sankaralingam M, Lee YM, Pineda-Galvan Y, Karmalkar DG, Seo MS, Jeon SH, Pushkar Y, Fukuzumi S, Nam W. Redox Reactivity of a Mononuclear Manganese-Oxo Complex Binding Calcium Ion and Other Redox-Inactive Metal Ions. J Am Chem Soc 2019; 141:1324-1336. [PMID: 30580510 DOI: 10.1021/jacs.8b11492] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mononuclear nonheme manganese(IV)-oxo complexes binding calcium ion and other redox-inactive metal ions, [(dpaq)MnIV(O)]+-M n+ (1-Mn+, M n+ = Ca2+, Mg2+, Zn2+, Lu3+, Y3+, Al3+, and Sc3+) (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino- N-quinolin-8-yl-acetamidate), were synthesized by reacting a hydroxomanganese(III) complex, [(dpaq)MnIII(OH)]+, with iodosylbenzene (PhIO) in the presence of redox-inactive metal ions (M n+). The Mn(IV)-oxo complexes were characterized using various spectroscopic techniques. In reactivity studies, we observed contrasting effects of M n+ on the reactivity of 1-M n+ in redox reactions such as electron-transfer (ET), oxygen atom transfer (OAT), and hydrogen atom transfer (HAT) reactions. In the OAT and ET reactions, the reactivity order of 1-M n+, such as 1-Sc3+ ≈ 1-Al3+ > 1-Y3+ > 1-Lu3+ > 1-Zn2+ > 1-Mg2+ > 1-Ca2+, follows the Lewis acidity of M n+ bound to the Mn-O moiety; that is, the stronger the Lewis acidity of M n+, the higher the reactivity of 1-M n+ becomes. In sharp contrast, the reactivity of 1-M n+ in the HAT reaction was reversed, giving the reactivity order 1-Ca2+ > 1-Mg2+ > 1-Zn2+ > 1-Lu3+> 1-Y3+> 1-Al3+ ≈ 1-Sc3+; that is, the higher is Lewis acidity of M n+, the lower the reactivity of 1-M n+ in the HAT reaction. The latter result implies that the Lewis acidity of M n+ bound to the Mn-O moiety can modulate the basicity of the metal-oxo moiety, thus influencing the HAT reactivity of 1-M n+; cytochrome P450 utilizes the axial thiolate ligand to increase the basicity of the iron-oxo moiety, which enhances the reactivity of compound I in C-H bond activation reactions.
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Affiliation(s)
| | - Yong-Min Lee
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Yuliana Pineda-Galvan
- Department of Physics and Astronomy , Purdue University , 525 Northwestern Avenue , West Lafayette , Indiana 47907 , United States
| | - Deepika G Karmalkar
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - So Hyun Jeon
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Yulia Pushkar
- Department of Physics and Astronomy , Purdue University , 525 Northwestern Avenue , West Lafayette , Indiana 47907 , United States
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,Faculty of Science and Engineering, SENTAN, Japan Science and Technology Agency (JST) , Meijo University , Nagoya , Aichi 468-8502 , Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP) , Chinese Academy of Sciences , Lanzhou , 730000 , China
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42
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Lu X, Li XX, Seo MS, Lee YM, Clémancey M, Maldivi P, Latour JM, Sarangi R, Fukuzumi S, Nam W. A Mononuclear Nonheme Iron(IV)-Amido Complex Relevant for the Compound II Chemistry of Cytochrome P450. J Am Chem Soc 2018; 141:80-83. [PMID: 30558411 DOI: 10.1021/jacs.8b11045] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A mononuclear nonheme iron(IV)-amido complex bearing a tetraamido macrocyclic ligand, [(TAML)FeIV(NHTs)]- (1), was synthesized via a hydrogen atom (H atom) abstraction reaction of an iron(V)-imido complex, [(TAML)FeV(NTs)]- (2), and fully characterized using various spectroscopies. We then investigated (1) the p Ka of 1, (2) the reaction of 1 with a carbon-centered radical, and (3) the H atom abstraction reaction of 1. To the best of our knowledge, the present study reports for the first time the synthesis and chemical properties/reactions of a high-valent iron(IV)-amido complex.
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Affiliation(s)
- Xiaoyan Lu
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Martin Clémancey
- Université Grenoble Alpes , CEA, CNRS, BIG, LCBM , Grenoble F-38000 , France
| | - Pascale Maldivi
- Université Grenoble Alpes , CEA, CNRS, INAC, SYMMES , Grenoble F-38000 , France
| | - Jean-Marc Latour
- Université Grenoble Alpes , CEA, CNRS, BIG, LCBM , Grenoble F-38000 , France
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Stanford , California 94025 , United States
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP , Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000 , China
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43
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Karmalkar DG, Li XX, Seo MS, Sankaralingam M, Ohta T, Sarangi R, Hong S, Nam W. A Manganese(V)-Oxo Tetraamido Macrocyclic Ligand (TAML) Cation Radical Complex: Synthesis, Characterization, and Reactivity Studies. Chemistry 2018; 24:17927-17931. [PMID: 30267428 DOI: 10.1002/chem.201804898] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Indexed: 11/06/2022]
Abstract
A mononuclear manganese(V)-oxo complex with tetraamido macrocyclic ligand (TAML), [MnV (O)(TAML)]- (1), is a sluggish oxidant in oxidation reactions. Herein, a mononuclear manganese(V)-oxo TAML cation radical complex, [MnV (O)(TAML+. )] (2), is reported. It was synthesized by reacting [MnIII (TAML)]- with 3.0 equivalents of [RuIII (bpy)3 ]3+ or upon addition of one-electron oxidant to 1 and then characterized thoroughly with various spectroscopic techniques along with DFT calculations. Although 1 is a sluggish oxidant, 2 is a strong oxidant capable of activating C-H bonds of hydrocarbons (i.e., hydrogen atom transfer reaction) and transferring its oxygen atom to thioanisoles and olefins (i.e., oxygen atom transfer reaction).
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Affiliation(s)
- Deepika G Karmalkar
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
| | | | - Takehiro Ohta
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH LP Center, Hyogo, 679-5148, Japan
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, California, 94025, USA
| | - Seungwoo Hong
- Department of Chemistry, Sookmyung Women's University, Seoul, 04310, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea
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44
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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: 145] [Impact Index Per Article: 24.2] [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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45
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Albertolle ME, Peter Guengerich F. The relationships between cytochromes P450 and H 2O 2: Production, reaction, and inhibition. J Inorg Biochem 2018; 186:228-234. [PMID: 29990746 PMCID: PMC6084448 DOI: 10.1016/j.jinorgbio.2018.05.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/25/2018] [Accepted: 05/23/2018] [Indexed: 12/26/2022]
Abstract
In this review we address the relationship between cytochromes P450 (P450) and H2O2. This association can affect biology in three distinct ways. First, P450s produce H2O2 as a byproduct either during catalysis or when no substrate is present. This reaction, known as uncoupling, releases reactive oxygen species that may have implications in disease. Second, H2O2 is used as an oxygen-donating co-substrate in peroxygenase and peroxidase reactions catalyzed by P450s. This activity has proven to be important mainly in reactions involving prokaryotic P450s, and investigators have harnessed this reaction with the aim of adaptation for industrial use. Third, H2O2-dependent inhibition of human P450s has been studied in our laboratory, demonstrating heme destruction and also the inactivating oxidation of the heme-thiolate ligand to a sulfenic acid (-SOH). This reversible oxidative modification of P450s may have implications in the prevention of uncoupling and may give new insights into the oxidative regulation of these enzymes. Research has elucidated many of the chemical mechanisms involved in the relationship between P450 and H2O2, but the application to biology is difficult to evaluate. Further studies are needed reveal both the harmful and protective natures of reactive oxygen species in an organismal context.
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Affiliation(s)
- Matthew E Albertolle
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, United States
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, United States.
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46
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Ligand Access Channels in Cytochrome P450 Enzymes: A Review. Int J Mol Sci 2018; 19:ijms19061617. [PMID: 29848998 PMCID: PMC6032366 DOI: 10.3390/ijms19061617] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/27/2018] [Accepted: 05/28/2018] [Indexed: 12/22/2022] Open
Abstract
Quantitative structure-activity relationships may bring invaluable information on structural elements of both enzymes and substrates that, together, govern substrate specificity. Buried active sites in cytochrome P450 enzymes are connected to the solvent by a network of channels exiting at the distal surface of the protein. This review presents different in silico tools that were developed to uncover such channels in P450 crystal structures. It also lists some of the experimental evidence that actually suggest that these predicted channels might indeed play a critical role in modulating P450 functions. Amino acid residues at the entrance of the channels may participate to a first global ligand recognition of ligands by P450 enzymes before they reach the buried active site. Moreover, different P450 enzymes show different networks of predicted channels. The plasticity of P450 structures is also important to take into account when looking at how channels might play their role.
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47
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Affiliation(s)
- Yujie Liang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Jialiang Wei
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Xu Qiu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
| | - Ning Jiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Road 38, Beijing 100191, China
- State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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48
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Ji L, Ji S, Wang C, Kepp KP. Molecular Mechanism of Alternative P450-Catalyzed Metabolism of Environmental Phenolic Endocrine-Disrupting Chemicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:4422-4431. [PMID: 29490136 DOI: 10.1021/acs.est.8b00601] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the bioactivation mechanisms to predict toxic metabolites is critical for risk assessment of phenolic endocrine-disrupting chemicals (EDCs). One mechanism involves ipso-substitution, which may contribute to the total turnover of phenolic EDCs, yet the detailed mechanism and its relationship with other mechanisms are unknown. We used density functional theory to investigate the P450-catalyzed ipso-substitution mechanism of the prominent xenoestrogen bisphenol A. The ipso-substitution proceeds via H-abstraction from bisphenol A by Compound I, followed by essentially barrierless OH-rebound onto the ipso-position forming a quinol, which can spontaneously decompose into the carbocation and hydroquinone. This carbocation can further evolve into the highly estrogenic hydroxylated and dimer-type metabolites. The H-abstraction/OH-rebound reaction mechanism has been verified as a general reaction mode for many other phenolic EDCs, such as bisphenol analogues, alkylphenols and chlorophenols. The identified mechanism enables us to effectively distinguish between type I (eliminating-substituent as anion) and type II (eliminating-substituent as cation) ipso-substitution in various phenolic EDCs. We envision that the identified pathways will be applicable for prediction of metabolites from phenolic EDCs whose fate are affected by this alternative type of P450 reactivity, and accordingly enable the screening of these metabolites for endocrine-disrupting activity.
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Affiliation(s)
- Li Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
- UFZ Department of Ecological Chemistry , Helmholtz Centre for Environmental Research , Permoserstrasse 15 , 04318 Leipzig , Germany
| | - Shujing Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
| | - Chenchen Wang
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
| | - Kasper P Kepp
- DTU Chemistry , Technical University of Denmark , Building 206 , Kongens Lyngby , DK-2800 , Denmark
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49
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Huang X, Groves JT. Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins. Chem Rev 2018; 118:2491-2553. [PMID: 29286645 PMCID: PMC5855008 DOI: 10.1021/acs.chemrev.7b00373] [Citation(s) in RCA: 591] [Impact Index Per Article: 98.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Indexed: 12/20/2022]
Abstract
As a result of the adaptation of life to an aerobic environment, nature has evolved a panoply of metalloproteins for oxidative metabolism and protection against reactive oxygen species. Despite the diverse structures and functions of these proteins, they share common mechanistic grounds. An open-shell transition metal like iron or copper is employed to interact with O2 and its derived intermediates such as hydrogen peroxide to afford a variety of metal-oxygen intermediates. These reactive intermediates, including metal-superoxo, -(hydro)peroxo, and high-valent metal-oxo species, are the basis for the various biological functions of O2-utilizing metalloproteins. Collectively, these processes are called oxygen activation. Much of our understanding of the reactivity of these reactive intermediates has come from the study of heme-containing proteins and related metalloporphyrin compounds. These studies not only have deepened our understanding of various functions of heme proteins, such as O2 storage and transport, degradation of reactive oxygen species, redox signaling, and biological oxygenation, etc., but also have driven the development of bioinorganic chemistry and biomimetic catalysis. In this review, we survey the range of O2 activation processes mediated by heme proteins and model compounds with a focus on recent progress in the characterization and reactivity of important iron-oxygen intermediates. Representative reactions initiated by these reactive intermediates as well as some context from prior decades will also be presented. We will discuss the fundamental mechanistic features of these transformations and delineate the underlying structural and electronic factors that contribute to the spectrum of reactivities that has been observed in nature as well as those that have been invented using these paradigms. Given the recent developments in biocatalysis for non-natural chemistries and the renaissance of radical chemistry in organic synthesis, we envision that new enzymatic and synthetic transformations will emerge based on the radical processes mediated by metalloproteins and their synthetic analogs.
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Affiliation(s)
- Xiongyi Huang
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department
of Chemistry, California Institute of Technology, Pasadena, California 91125, United States
| | - John T. Groves
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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Merlini ML, Britovsek GJP, Swart M, Belanzoni P. Understanding the Catalase-Like Activity of a Bioinspired Manganese(II) Complex with a Pentadentate NSNSN Ligand Framework. A Computational Insight into the Mechanism. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maria Letizia Merlini
- Laboratoire de Chimie et Biochimie Computationnelles, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), Av. F.-A. Forel 2, CH-1015 Lausanne, Switzerland
| | - George J. P. Britovsek
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Facultat de Ciències, 17003 Girona, Spain
- Institució Catalana de Recerca i Estudis Avançats ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Paola Belanzoni
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
- Istituto di Scienze e Tecnologie Molecolari del CNR CNR-ISTM, c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS)2, via Elce di Sotto 8, 06123 Perugia, Italy
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