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Milić JV, Schneeberger T, Zalibera M, Diederich F, Boudon C, Ruhlmann L. Spectro-electrochemical toolbox for monitoring and controlling quinone-mediated redox-driven molecular gripping. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.04.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Jasniewski AJ, Que L. Dioxygen Activation by Nonheme Diiron Enzymes: Diverse Dioxygen Adducts, High-Valent Intermediates, and Related Model Complexes. Chem Rev 2018; 118:2554-2592. [PMID: 29400961 PMCID: PMC5920527 DOI: 10.1021/acs.chemrev.7b00457] [Citation(s) in RCA: 304] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A growing subset of metalloenzymes activates dioxygen with nonheme diiron active sites to effect substrate oxidations that range from the hydroxylation of methane and the desaturation of fatty acids to the deformylation of fatty aldehydes to produce alkanes and the six-electron oxidation of aminoarenes to nitroarenes in the biosynthesis of antibiotics. A common feature of their reaction mechanisms is the formation of O2 adducts that evolve into more reactive derivatives such as diiron(II,III)-superoxo, diiron(III)-peroxo, diiron(III,IV)-oxo, and diiron(IV)-oxo species, which carry out particular substrate oxidation tasks. In this review, we survey the various enzymes belonging to this unique subset and the mechanisms by which substrate oxidation is carried out. We examine the nature of the reactive intermediates, as revealed by X-ray crystallography and the application of various spectroscopic methods and their associated reactivity. We also discuss the structural and electronic properties of the model complexes that have been found to mimic salient aspects of these enzyme active sites. Much has been learned in the past 25 years, but key questions remain to be answered.
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Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Milić J, Zalibera M, Talaat D, Nomrowski J, Trapp N, Ruhlmann L, Boudon C, Wenger OS, Savitsky A, Lubitz W, Diederich F. Photoredox-Switchable Resorcin[4]arene Cavitands: Radical Control of Molecular Gripping Machinery via Hydrogen Bonding. Chemistry 2017; 24:1431-1440. [DOI: 10.1002/chem.201704788] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Indexed: 01/10/2023]
Affiliation(s)
- Jovana Milić
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Michal Zalibera
- Institute of Physical Chemistry and Chemical Physics; Slovak University of Technology; Radlinského 9 81237 Bratislava Slovakia
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Darius Talaat
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Julia Nomrowski
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 4056 Basel Switzerland
| | - Nils Trapp
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Laurent Ruhlmann
- Laboratoire d'Électrochimie et Chimie Physique du Corps Solide, Institut de Chimie de Strasbourg; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
| | - Corinne Boudon
- Laboratoire d'Électrochimie et Chimie Physique du Corps Solide, Institut de Chimie de Strasbourg; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
| | - Oliver S. Wenger
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 4056 Basel Switzerland
| | - Anton Savitsky
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - François Diederich
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
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Bhagi-Damodaran A, Hosseinzadeh P, Mirts E, Reed J, Petrik ID, Lu Y. Design of Heteronuclear Metalloenzymes. Methods Enzymol 2016; 580:501-37. [PMID: 27586347 PMCID: PMC5156654 DOI: 10.1016/bs.mie.2016.05.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Heteronuclear metalloenzymes catalyze some of the most fundamentally interesting and practically useful reactions in nature. However, the presence of two or more metal ions in close proximity in these enzymes makes them more difficult to prepare and study than homonuclear metalloenzymes. To meet these challenges, heteronuclear metal centers have been designed into small and stable proteins with rigid scaffolds to understand how these heteronuclear centers are constructed and the mechanism of their function. This chapter describes methods for designing heterobinuclear metal centers in a protein scaffold by giving specific examples of a few heme-nonheme bimetallic centers engineered in myoglobin and cytochrome c peroxidase. We provide step-by-step procedures on how to choose the protein scaffold, design a heterobinuclear metal center in the protein scaffold computationally, incorporate metal ions into the protein, and characterize the resulting metalloproteins, both structurally and functionally. Finally, we discuss how an initial design can be further improved by rationally tuning its secondary coordination sphere, electron/proton transfer rates, and the substrate affinity.
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Affiliation(s)
- A Bhagi-Damodaran
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - P Hosseinzadeh
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - E Mirts
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - J Reed
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - I D Petrik
- University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Y Lu
- University of Illinois at Urbana-Champaign, Urbana, IL, United States.
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Bucinsky L, Rohde GT, Que L, Ozarowski A, Krzystek J, Breza M, Telser J. HFEPR and Computational Studies on the Electronic Structure of a High-Spin Oxidoiron(IV) Complex in Solution. Inorg Chem 2016; 55:3933-45. [PMID: 27031000 DOI: 10.1021/acs.inorgchem.6b00169] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonheme iron enzymes perform diverse and important functions in biochemistry. The active form of these enzymes comprises the ferryl, oxidoiron(IV), [FeO](2+) unit. In enzymes, this unit is in the high-spin, quintet, S = 2, ground state, while many synthetic model compounds exist in the spin triplet, S = 1, ground state. Recently, however, Que and co-workers reported an oxidoiron(IV) complex with a quintet ground state, [FeO(TMG3tren)](OTf)2, where TMG3tren = 1,1,1-tris{2-[N2-(1,1,3,3-tetramethylguanidino)]ethyl}amine and OTf = CF3SO3(-). The trigonal geometry imposed by this ligand, as opposed to the tetragonal geometry of earlier model complexes, favors the high-spin ground state. Although [FeO(TMG3tren)](2+) has been earlier probed by magnetic circular dichroism (MCD) and Mössbauer spectroscopies, the technique of high-frequency and -field electron paramagnetic resonance (HFEPR) is superior for describing the electronic structure of the iron(IV) center because of its ability to establish directly the spin-Hamiltonian parameters of high-spin metal centers with high precision. Herein we describe HFEPR studies on [FeO(TMG3tren)](OTf)2 generated in situ and confirm the S = 2 ground state with the following parameters: D = +4.940(5) cm(-1), E = 0.000(5), B4(0) = -14(1) × 10(-4) cm(-1), g⊥ = 2.006(2), and g∥ = 2.03(2). Extraction of a fourth-order spin-Hamiltonian parameter is unusual for HFEPR and impossible by other techniques. These experimental results are combined with state-of-the-art computational studies along with previous structural and spectroscopic results to provide a complete picture of the electronic structure of this biomimetic complex. Specifically, the calculations reproduce well the spin-Hamiltonian parameters of the complex, provide a satisfying geometrical picture of the S = 2 oxidoiron(IV) moiety, and demonstrate that the TMG3tren is an "innocent" ligand.
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Affiliation(s)
- Lukas Bucinsky
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology , Radlinského 9, SK-81237 Bratislava, Slovakia
| | - Gregory T Rohde
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States
| | - Martin Breza
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology , Radlinského 9, SK-81237 Bratislava, Slovakia
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University , Chicago, Illinois 60605, United States
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Abstract
![]()
2003 marked a banner year in the bioinorganic chemistry of mononuclear
non-heme iron enzymes. The first non-heme oxoiron(IV) intermediate
(called J) was trapped and characterized
by Bollinger and Krebs in the catalytic cycle of taurine dioxygenase
(TauD), and the first crystal structure of a synthetic non-heme oxoiron(IV)
complex was reported by Münck, Nam, and Que. These results
stimulated inorganic chemists to synthesize related oxoiron(IV) complexes
to shed light on the electronic structures and spectroscopic properties
of these novel intermediates and gain mechanistic insights into their
function in biology. All of the biological oxoiron(IV) intermediates
discovered since 2003 have an S = 2 ground spin state,
while over 90% of the 60 or so synthetic oxoiron(IV) complexes reported
to date have an S = 1 ground spin state. This difference
in electronic structure has fueled an interest to more accurately
model these enzymatic intermediates and synthesize S = 2 oxoiron(IV) complexes. This Account follows up on a previous
Account (Acc. Chem.
Res. 2007, 40, 493) that provided
a perspective on the early developments in this field up to 2007 and
details our group’s efforts in the development of synthetic
strategies to obtain oxoiron(IV) complexes with an S = 2 ground state. Upon inspection of a qualitative d-orbital splitting
diagram for a d4 metal–oxo center, it becomes evident
that the key to achieving an S = 2 ground state is
to decrease the energy gap between the dx2–y2 and
dxy orbitals. Described below are two
different synthetic strategies we used to accomplish this goal. The first strategy took advantage of the realization that the dx2–y2 and dxy orbitals become
degenerate in a C3-symmetric ligand environment.
Thus, by employing bulky tripodal ligands, trigonal-bipyramidal S = 2 oxoiron(IV) complexes were obtained. However, substrate
access to the oxoiron(IV) center was hindered by the bulky ligands,
and the complexes showed limited ability to cleave substrate C–H
bonds. The second strategy entailed introducing weaker-field equatorial
ligands in six-coordinate oxoiron(IV) complexes to decrease the dx2–y2/dxy energy gap to
the point where the S = 2 ground state is favored.
These pseudo-octahedral S = 2 oxoiron(IV) complexes
exhibit high H-atom transfer reactivity relative to their S = 1 counterparts and shed light on the role that the spin
state may play in these reactions. Among these complexes is a highly
reactive species that to date represents the closest electronic and
functional model of the enzymatic intermediate, TauD-J.
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Affiliation(s)
- Mayank Puri
- Department
of Chemistry and
Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department
of Chemistry and
Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Yoon H, Lee YM, Wu X, Cho KB, Sarangi R, Nam W, Fukuzumi S. Enhanced electron-transfer reactivity of nonheme manganese(IV)-oxo complexes by binding scandium ions. J Am Chem Soc 2013; 135:9186-94. [PMID: 23742163 PMCID: PMC3934761 DOI: 10.1021/ja403965h] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
One and two scandium ions (Sc(3+)) are bound strongly to nonheme manganese(IV)-oxo complexes, [(N4Py)Mn(IV)(O)](2+) (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) and [(Bn-TPEN)Mn(IV)(O)](2+) (Bn-TPEN = N-benzyl-N,N',N'-tris(2-pyridylmethyl)-1,2-diaminoethane), to form Mn(IV)(O)-(Sc(3+))1 and Mn(IV)(O)-(Sc(3+))2 complexes, respectively. The binding of Sc(3+) ions to the Mn(IV)(O) complexes was examined by spectroscopic methods as well as by DFT calculations. The one-electron reduction potentials of the Mn(IV)(O) complexes were markedly shifted to a positive direction by binding of Sc(3+) ions. Accordingly, rates of the electron transfer reactions of the Mn(IV)(O) complexes were enhanced as much as 10(7)-fold by binding of two Sc(3+) ions. The driving force dependence of electron transfer from various electron donors to the Mn(IV)(O) and Mn(IV)(O)-(Sc(3+))2 complexes was examined and analyzed in light of the Marcus theory of electron transfer to determine the reorganization energies of electron transfer. The smaller reorganization energies and much more positive reduction potentials of the Mn(IV)(O)-(Sc(3+))2 complexes resulted in remarkable enhancement of the electron-transfer reactivity of the Mn(IV)(O) complexes. Such a dramatic enhancement of the electron-transfer reactivity of the Mn(IV)(O) complexes by binding of Sc(3+) ions resulted in the change of mechanism in the sulfoxidation of thioanisoles by Mn(IV)(O) complexes from a direct oxygen atom transfer pathway without metal ion binding to an electron-transfer pathway with binding of Sc(3+) ions.
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Affiliation(s)
- Heejung Yoon
- Department of Material and Life Science, Graduate School of Engineering, ALCA, Japan Science and Technology Agency (JST), Osaka University, Suita, Osaka 565-0871, Japan
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Yong-Min Lee
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Xiujuan Wu
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Kyung-Bin Cho
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Ritimukta Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Wonwoo Nam
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Shunichi Fukuzumi
- Department of Material and Life Science, Graduate School of Engineering, ALCA, Japan Science and Technology Agency (JST), Osaka University, Suita, Osaka 565-0871, Japan
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
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Xue G, Geng C, Ye S, Fiedler AT, Neese F, Que L. Hydrogen-bonding effects on the reactivity of [X-Fe(III)-O-Fe(IV)═O] (X = OH, F) complexes toward C-H bond cleavage. Inorg Chem 2013; 52:3976-84. [PMID: 23496330 DOI: 10.1021/ic3027896] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Complexes 1-OH and 1-F are related complexes that share similar [X-Fe(III)-O-Fe(IV)═O](3+) core structures with a total spin S of ½, which arises from antiferromagnetic coupling of an S = 5/2 Fe(III)-X site and an S = 2 Fe(IV)═O site. EXAFS analysis shows that 1-F has a nearly linear Fe(III)-O-Fe(IV) core compared to that of 1-OH, which has an Fe-O-Fe angle of ~130° due to the presence of a hydrogen bond between the hydroxo and oxo groups. Both complexes are at least 1000-fold more reactive at C-H bond cleavage than 2, a related complex with a [OH-Fe(IV)-O-Fe(IV)═O](4+) core having individual S = 1 Fe(IV) units. Interestingly, 1-F is 10-fold more reactive than 1-OH. This raises an interesting question about what gives rise to the reactivity difference. DFT calculations comparing 1-OH and 1-F strongly suggest that the H-bond in 1-OH does not significantly change the electrophilicity of the reactive Fe(IV)═O unit and that the lower reactivity of 1-OH arises from the additional activation barrier required to break its H-bond in the course of H-atom transfer by the oxoiron(IV) moiety.
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Affiliation(s)
- Genqiang Xue
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
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