1
|
DeLucia AA, Olshansky L. Carboxylate Shift Dynamics in Biomimetic Co 2(μ-OH) 2 Complexes. Inorg Chem 2024; 63:1109-1118. [PMID: 38170989 DOI: 10.1021/acs.inorgchem.3c03470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Carboxylate shift mechanisms provide low-energy pathways to accommodate changes in oxidation state and coordination number required during catalysis in metalloenzyme active sites. These processes are challenging to observe in their native enzymes and molecular models can provide insight into their mechanistic details. We report here the direct observation of a carboxylate shift reaction in biomimetic yet structurally stable dicobalt complexes featuring both monodentate and bridging acetate ligands, as well as intramolecular hydrogen-bonding interactions. Subjecting the series of complexes [Co2(μ-OH)2(μ-1,3-OAc)(κ-OAc)2(pyR)4]PF6 ([1R]PF6, OAc = acetate, pyR = pyridine with para-R substituents: OMe, H, or CN) to a Lewis acid triggers conversion of a monodentate acetate to a μ-1,3 bridging mode, forming [Co2(μ-OH)2(μ-1,3-OAc)2(pyR)4]2+ ([2R]2+). [2R]2+ is susceptible to solvent binding, affording [Co2(μ-OH)2(μ-1,3-OAc)(κ-OAc)(MeCN)(pyR)4]2+ ([3R]2+) in MeCN. These reaction products and intermediates were isolated and characterized in the solid state by isotopic labeling and Fourier transform infrared (FTIR) spectroscopy, as well as by X-ray diffraction. The kinetics of the formation and decay of [1R]+, [2R]2+, and [3R]2+ were also examined in situ by 1H-NMR spectroscopy to provide a kinetic model for the carboxylate shift reaction. The rate constants extracted from global fit analyses of these reactions increase with increasing electron donation from R. Leveraging robust diamagnetic CoIII complexes, these studies provide mechanistic details of carboxylate shift reactivity and highlight the utility of ligand dynamicity in mediating the transient formation of unstable metal complexes.
Collapse
Affiliation(s)
- Alyssa A DeLucia
- Department of Chemistry, Center for Biophysics and Quantitative Biology, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3028, United States
| | - Lisa Olshansky
- Department of Chemistry, Center for Biophysics and Quantitative Biology, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3028, United States
| |
Collapse
|
2
|
Kajita Y, Kubo M, Arii H, Ishikawa S, Saito Y, Wasada-Tsutsui Y, Funahashi Y, Ozawa T, Masuda H. Preparations of trans- and cis- μ-1,2-Peroxodiiron(III) Complexes. Molecules 2023; 29:205. [PMID: 38202788 PMCID: PMC10780643 DOI: 10.3390/molecules29010205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
The iron(II) complex with cis,cis-1,3,5-tris(benzylamino)cyclohexane (Bn3CY) (1) has been synthesized and characterized, which reacted with dioxygen to form the peroxo complex 2 in acetone at -60 °C. On the basis of spectroscopic measurements for 2, it was confirmed that the peroxo complex 2 has a trans-μ-1,2 fashion. Additionally, the peroxo complex 2 was reacted with benzoate anion as a bridging agent to give a peroxo complex 3. The results of resonance Raman and 1H-NMR studies supported that the peroxo complex 3 is a cis-μ-1,2-peroxodiiron(III) complex. These spectral features were interpreted by using DFT calculations.
Collapse
Affiliation(s)
- Yuji Kajita
- Department of Applied Chemistry, Graduate School of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan;
| | - Masaki Kubo
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Hidekazu Arii
- Department of Education, Graduate School of Education, University of Miyazaki, Gakuenkibanadai-Nishi, Miyazaki 889-2192, Japan;
| | - Shinya Ishikawa
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yamato Saito
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yuko Wasada-Tsutsui
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yasuhiro Funahashi
- Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-0043, Japan;
| | - Tomohiro Ozawa
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Hideki Masuda
- Department of Applied Chemistry, Graduate School of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan;
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| |
Collapse
|
3
|
Gordon JB, Albert T, Dey A, Sabuncu S, Siegler MA, Bill E, Moënne-Loccoz P, Goldberg DP. A Reactive, Photogenerated High-Spin ( S = 2) Fe IV(O) Complex via O 2 Activation. J Am Chem Soc 2021; 143:21637-21647. [PMID: 34913683 PMCID: PMC9109941 DOI: 10.1021/jacs.1c10051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Addition of dioxygen at low temperature to the non-heme ferrous complex FeII(Me3TACN)((OSiPh2)2O) (1) in 2-MeTHF produces a peroxo-bridged diferric complex Fe2III(μ-O2)(Me3TACN)2((OSiPh2)2O)2 (2), which was characterized by UV-vis, resonance Raman, and variable field Mössbauer spectroscopies. Illumination of a frozen solution of 2 in THF with white light leads to homolytic O-O bond cleavage and generation of a FeIV(O) complex 4 (ν(Fe=O) = 818 cm-1; δ = 0.22 mm s-1, ΔEQ = 0.23 mm s-1). Variable field Mössbauer spectroscopy measurements show that 4 is a rare example of a high-spin S = 2 FeIV(O) complex and the first synthetic example to be generated directly from O2. Complex 4 is highly reactive, as expected for a high-spin ferryl, and decays rapidly in fluid solution at cryogenic temperatures. This decay process in 2-MeTHF involves C-H cleavage of the solvent. However, the controlled photolysis of 2 in situ with visible light and excess phenol substrate leads to competitive phenol oxidation, via the proposed transient generation of 4 as the active oxidant.
Collapse
Affiliation(s)
- Jesse B. Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Sinan Sabuncu
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Maxime A. Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Eckhard Bill
- Department of Inorganic Spectroscopy / Joint Workspace, Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim-an-der-Ruhr, Germany,Corresponding Author: , ,
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA,Corresponding Author: , ,
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA,Corresponding Author: , ,
| |
Collapse
|
4
|
Török P, Unjaroen D, Viktória Csendes F, Giorgi M, Browne WR, Kaizer J. A nonheme peroxo-diiron(III) complex exhibiting both nucleophilic and electrophilic oxidation of organic substrates. Dalton Trans 2021; 50:7181-7185. [PMID: 34019062 PMCID: PMC8168641 DOI: 10.1039/d1dt01502h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The complex [FeIII2(μ-O2)(L3)4(S)2]4+ (L3 = 2-(4-thiazolyl)benzimidazole, S = solvent) forms upon reaction of [FeII(L3)2] with H2O2 and is a functional model of peroxo-diiron intermediates invoked during the catalytic cycle of oxidoreductases. The spectroscopic properties of the complex are in line with those of complexes formed with N-donor ligands. [FeIII2(μ-O2)(L3)4(S)2]4+ shows both nucleophilic (aldehydes) and electrophilic (phenol, N,N-dimethylanilines) oxidative reactivity and unusually also electron transfer oxidation. A bidentate ligand based iron complex shows nucleophillic and electrophillice reactivity in the oxidation of organic substrates.![]()
Collapse
Affiliation(s)
- Patrik Török
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8200 Veszprém, Hungary.
| | - Duenpen Unjaroen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - Flóra Viktória Csendes
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8200 Veszprém, Hungary.
| | - Michel Giorgi
- Aix-Marseille Université, FR1739, Spectropole, Campus St Jérome, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France
| | - Wesley R Browne
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8200 Veszprém, Hungary.
| |
Collapse
|
5
|
Banerjee S, Draksharapu A, Crossland PM, Fan R, Guo Y, Swart M, Que L. Sc 3+-Promoted O-O Bond Cleavage of a (μ-1,2-Peroxo)diiron(III) Species Formed from an Iron(II) Precursor and O 2 to Generate a Complex with an Fe IV2(μ-O) 2 Core. J Am Chem Soc 2020; 142:4285-4297. [PMID: 32017545 DOI: 10.1021/jacs.9b12081] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Soluble methane monooxygenase (sMMO) carries out methane oxidation at 4 °C and under ambient pressure in a catalytic cycle involving the formation of a peroxodiiron(III) intermediate (P) from the oxygenation of the diiron(II) enzyme and its subsequent conversion to Q, the diiron(IV) oxidant that hydroxylates methane. Synthetic diiron(IV) complexes that can serve as models for Q are rare and have not been generated by a reaction sequence analogous to that of sMMO. In this work, we show that [FeII(Me3NTB)(CH3CN)](CF3SO3)2 (Me3NTB = tris((1-methyl-1H-benzo[d]imidazol-2-yl)methyl)amine) (1) reacts with O2 in the presence of base, generating a (μ-1,2-peroxo)diiron(III) adduct with a low O-O stretching frequency of 825 cm-1 and a short Fe···Fe distance of 3.07 Å. Even more interesting is the observation that the peroxodiiron(III) complex undergoes O-O bond cleavage upon treatment with the Lewis acid Sc3+ and transforms into a bis(μ-oxo)diiron(IV) complex, thus providing a synthetic precedent for the analogous conversion of P to Q in the catalytic cycle of sMMO.
Collapse
Affiliation(s)
- Saikat Banerjee
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Patrick M Crossland
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Marcel Swart
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.,IQCC and Department of Chemistry, University of Girona, 17003 Girona, Spain
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
6
|
Trehoux A, Guillot R, Clemancey M, Blondin G, Latour JM, Mahy JP, Avenier F. Bioinspired symmetrical and unsymmetrical diiron complexes for selective oxidation catalysis with hydrogen peroxide. Dalton Trans 2020; 49:16657-16661. [DOI: 10.1039/d0dt03308a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Two new symmetrical and unsymmetrical diiron(iii) complexes were synthesized and characterized by X-ray diffraction analysis, mass spectrometry, UV-visible and Mössbauer spectroscopies. They were then used for selective oxidation catalysis.
Collapse
Affiliation(s)
- Alexandre Trehoux
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | - Régis Guillot
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | | | | | | | - Jean-Pierre Mahy
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | - Frédéric Avenier
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| |
Collapse
|
7
|
Gordon JB, Vilbert AC, DiMucci IM, MacMillan SN, Lancaster KM, Moënne-Loccoz P, Goldberg DP. Activation of Dioxygen by a Mononuclear Nonheme Iron Complex: Sequential Peroxo, Oxo, and Hydroxo Intermediates. J Am Chem Soc 2019; 141:17533-17547. [PMID: 31647656 DOI: 10.1021/jacs.9b05274] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The activation of dioxygen by FeII(Me3TACN)(S2SiMe2) (1) is reported. Reaction of 1 with O2 at -135 °C in 2-MeTHF generates a thiolate-ligated (peroxo)diiron complex FeIII2(O2)(Me3TACN)2(S2SiMe2)2 (2) that was characterized by UV-vis (λmax = 300, 390, 530, 723 nm), Mössbauer (δ = 0.53, |ΔEQ| = 0.76 mm s-1), resonance Raman (RR) (ν(O-O) = 849 cm-1), and X-ray absorption (XAS) spectroscopies. Complex 2 is distinct from the outer-sphere oxidation product 1ox (UV-vis (λmax = 435, 520, 600 nm), Mössbauer (δ = 0.45, |ΔEQ| = 3.6 mm s-1), and EPR (S = 5/2, g = [6.38, 5.53, 1.99])), obtained by one-electron oxidation of 1. Cleavage of the peroxo O-O bond can be initiated either photochemically or thermally to produce a new species assigned as an FeIV(O) complex, FeIV(O)(Me3TACN)(S2SiMe2) (3), which was identified by UV-vis (λmax = 385, 460, 890 nm), Mössbauer (δ = 0.21, |ΔEQ| = 1.57 mm s-1), RR (ν(FeIV═O) = 735 cm-1), and X-ray absorption spectroscopies, as well as reactivity patterns. Reaction of 3 at low temperature with H atom donors gives a new species, FeIII(OH)(Me3TACN)(S2SiMe2) (4). Complex 4 was independently synthesized from 1 by the stoichiometric addition of a one-electron oxidant and a hydroxide source. This work provides a rare example of dioxygen activation at a mononuclear nonheme iron(II) complex that produces both FeIII-O-O-FeIII and FeIV(O) species in the same reaction with O2. It also demonstrates the feasibility of forming Fe/O2 intermediates with strongly donating sulfur ligands while avoiding immediate sulfur oxidation.
Collapse
Affiliation(s)
- Jesse B Gordon
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Avery C Vilbert
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry , Oregon Health & Science University , Portland , Oregon 97239 , United States
| | - David P Goldberg
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| |
Collapse
|
8
|
Kripli B, Csendes FV, Török P, Speier G, Kaizer J. Stoichiometric Aldehyde Deformylation Mediated by Nucleophilic Peroxo-diiron(III) Complex as a Functional Model of Aldehyde Deformylating Oxygenase. Chemistry 2019; 25:14290-14294. [PMID: 31448834 DOI: 10.1002/chem.201903727] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Indexed: 11/11/2022]
Abstract
The reactivity of the previously reported peroxo adduct [FeIII 2 (μ-O2 )(MeBzim-Py)4 (CH3 CN)2 ]4+ (1) (MeBzim-Py=2-(2'-pyridyl)-N-methylbenzimidazole) towards aldehyde substrates including phenylacetaldehyde (PAA), hydrocinnamaldehyde (HCA), propionaldehyde (PA), 2-phenylpropionaldehyde (PPA), cyclohexanecarboxaldehyde (CCA), and para-substituted benzaldehydes (benzoyl chlorides) has been investigated. Complex 1 proved to be a nucleophilic oxidant in aldehyde deformylation reaction. These models, including detailed kinetic and mechanistic studies, may serve as the first biomimics of aldehyde deformylating oxygenase (ADO) enzymes.
Collapse
Affiliation(s)
- Balázs Kripli
- Department of Chemistry, University of Pannonia, 8201, Veszprém, Hungary
| | | | - Patrik Török
- Department of Chemistry, University of Pannonia, 8201, Veszprém, Hungary
| | - Gábor Speier
- Department of Chemistry, University of Pannonia, 8201, Veszprém, Hungary
| | - József Kaizer
- Department of Chemistry, University of Pannonia, 8201, Veszprém, Hungary
| |
Collapse
|
9
|
Magherusan AM, Nelis DN, Twamley B, McDonald AR. Catechol oxidase activity of comparable dimanganese and dicopper complexes. Dalton Trans 2018; 47:15555-15564. [PMID: 30345446 DOI: 10.1039/c8dt01378k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthetic Cu complexes have been widely investigated as model systems for catechol oxidase enzymes. The catechol oxidase reactivity of Mn complexes has been less explored, and the effect of metal substitution in catecholase mimics has not been explored. A series of Mn and Cu complexes supported by the same poly-benzimidazole ligand framework have been synthesised and investigated in catecholase activity in acetonitrile medium using 3,5-di-tert-butylcatechol (3,5-DTBC) as a substrate. The Cu complexes proved to be good catechol oxidase mimics with moderate kcat values (∼45 h-1). The kinetic parameters for Mn complexes exhibited lower kcat values (∼8-40 h-1) when compared to the Cu complexes. Our findings demonstrate that later transition metals supported by relatively electron rich ligands yield the highest kcat values for catechol oxidation.
Collapse
Affiliation(s)
- Adriana M Magherusan
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.
| | | | | | | |
Collapse
|
10
|
Komor AJ, Jasniewski AJ, Que L, Lipscomb JD. Diiron monooxygenases in natural product biosynthesis. Nat Prod Rep 2018; 35:646-659. [PMID: 29552683 PMCID: PMC6051903 DOI: 10.1039/c7np00061h] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to 2017 The participation of non-heme dinuclear iron cluster-containing monooxygenases in natural product biosynthetic pathways has been recognized only recently. At present, two families have been discovered. The archetypal member of the first family, CmlA, catalyzes β-hydroxylation of l-p-aminophenylalanine (l-PAPA) covalently linked to the nonribosomal peptide synthetase (NRPS) CmlP, thereby effecting the first step in the biosynthesis of chloramphenicol by Streptomyces venezuelae. CmlA houses the diiron cluster in a metallo-β-lactamase protein fold instead of the 4-helix bundle fold of nearly every other diiron monooxygenase. CmlA couples O2 activation and substrate hydroxylation via a structural change caused by formation of the l-PAPA-loaded CmlP:CmlA complex. The other new diiron family is typified by two enzymes, AurF and CmlI, which catalyze conversion of aryl-amine substrates to aryl-nitro products with incorporation of oxygen from O2. AurF from Streptomyces thioluteus catalyzes the formation of p-nitrobenzoate from p-aminobenzoate as a precursor to the biostatic compound aureothin, whereas CmlI from S. venezuelae catalyzes the ultimate aryl-amine to aryl-nitro step in chloramphenicol biosynthesis. Both enzymes stabilize a novel type of peroxo-intermediate as the reactive species. The rare 6-electron N-oxygenation reactions of CmlI and AurF involve two progressively oxidized pathway intermediates. The enzymes optimize efficiency by utilizing one of the reaction pathway intermediates as an in situ reductant for the diiron cluster, while simultaneously generating the next pathway intermediate. For CmlI, this reduction allows mid-pathway regeneration of the peroxo intermediate required to complete the biosynthesis. CmlI ensures specificity by carrying out the multistep aryl-amine oxygenation without dissociating intermediate products.
Collapse
Affiliation(s)
- Anna J Komor
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - Andrew J Jasniewski
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| |
Collapse
|
11
|
Zimmermann TP, Limpke T, Stammler A, Bögge H, Walleck S, Glaser T. Reversible Carboxylate Shift in a μ-Oxo Diferric Complex in Solution by Acid-/Base-Addition. Inorg Chem 2018; 57:5400-5405. [DOI: 10.1021/acs.inorgchem.8b00376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Philipp Zimmermann
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Thomas Limpke
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Anja Stammler
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Hartmut Bögge
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Stephan Walleck
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| |
Collapse
|
12
|
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: 316] [Impact Index Per Article: 52.7] [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.
Collapse
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
| |
Collapse
|
13
|
Fan R, Serrano-Plana J, Oloo WN, Draksharapu A, Delgado-Pinar E, Company A, Martin-Diaconescu V, Borrell M, Lloret-Fillol J, García-España E, Guo Y, Bominaar EL, Que L, Costas M, Münck E. Spectroscopic and DFT Characterization of a Highly Reactive Nonheme Fe V-Oxo Intermediate. J Am Chem Soc 2018; 140:3916-3928. [PMID: 29463085 DOI: 10.1021/jacs.7b11400] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The reaction of [(PyNMe3)FeII(CF3SO3)2], 1, with excess peracetic acid at -40 °C generates a highly reactive intermediate, 2b(PAA), that has the fastest rate to date for oxidizing cyclohexane by a nonheme iron species. It exhibits an intense 490 nm chromophore associated with an S = 1/2 EPR signal having g-values at 2.07, 2.01, and 1.94. This species was shown to be in a fast equilibrium with a second S = 1/2 species, 2a(PAA), assigned to a low-spin acylperoxoiron(III) center. Unfortunately, contaminants accompanying the 2(PAA) samples prevented determination of the iron oxidation state by Mössbauer spectroscopy. Use of MeO-PyNMe3 (an electron-enriched version of PyNMe3) and cyclohexyl peroxycarboxylic acid as oxidant affords intermediate 3b(CPCA) with a Mössbauer isomer shift δ = -0.08 mm/s that indicates an iron(V) oxidation state. Analysis of the Mössbauer and EPR spectra, combined with DFT studies, demonstrates that the electronic ground state of 3b(CPCA) is best described as a quantum mechanical mixture of [(MeO-PyNMe3)FeV(O)(OC(O)R)]2+ (∼75%) with some FeIV(O)(•OC(O)R) and FeIII(OOC(O)R) character. DFT studies of 3b(CPCA) reveal that the unbound oxygen of the carboxylate ligand, O2, is only 2.04 Å away from the oxo group, O1, corresponding to a Wiberg bond order for the O1-O2 bond of 0.35. This unusual geometry facilitates reversible O1-O2 bond formation and cleavage and accounts for the high reactivity of the intermediate when compared to the rates of hydrogen atom transfer and oxygen atom transfer reactions of FeIII(OC(O)R) ferric acyl peroxides and FeIV(O) complexes. The interaction of O2 with O1 leads to a significant downshift of the Fe-O1 Raman frequency (815 cm-1) relative to the 903 cm-1 value predicted for the hypothetical [(MeO-PyNMe3)FeV(O)(NCMe)]3+ complex.
Collapse
Affiliation(s)
- Ruixi Fan
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Joan Serrano-Plana
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Williamson N Oloo
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - Estefanía Delgado-Pinar
- Grup de Química Supramolecular, Institut de Ciència Molecular, Departament de Química Inorgànica , Universitat de València , 46980 Paterna , Valencia , Spain
| | - Anna Company
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Vlad Martin-Diaconescu
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Margarida Borrell
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Julio Lloret-Fillol
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avinguda Països Catalans 16 , 43007 Tarragona , Spain
| | - Enrique García-España
- Grup de Química Supramolecular, Institut de Ciència Molecular, Departament de Química Inorgànica , Universitat de València , 46980 Paterna , Valencia , Spain
| | - Yisong Guo
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Emile L Bominaar
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455 , United States
| | - Miquel Costas
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Eckard Münck
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| |
Collapse
|
14
|
Jasniewski AJ, Komor AJ, Lipscomb JD, Que L. Unprecedented (μ-1,1-Peroxo)diferric Structure for the Ambiphilic Orange Peroxo Intermediate of the Nonheme N-Oxygenase CmlI. J Am Chem Soc 2017; 139:10472-10485. [PMID: 28673082 PMCID: PMC5568637 DOI: 10.1021/jacs.7b05389] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The final step in the biosynthesis of the antibiotic chloramphenicol is the oxidation of an aryl-amine substrate to an aryl-nitro product catalyzed by the N-oxygenase CmlI in three two-electron steps. The CmlI active site contains a diiron cluster ligated by three histidine and four glutamate residues and activates dioxygen to perform its role in the biosynthetic pathway. It was previously shown that the active oxidant used by CmlI to facilitate this chemistry is a peroxo-diferric intermediate (CmlIP). Spectroscopic characterization demonstrated that the peroxo binding geometry of CmlIP is not consistent with the μ-1,2 mode commonly observed in nonheme diiron systems. Its geometry was tentatively assigned as μ-η2:η1 based on comparison with resonance Raman (rR) features of mixed-metal model complexes in the absence of appropriate diiron models. Here, X-ray absorption spectroscopy (XAS) and rR studies have been used to establish a refined structure for the diferric cluster of CmlIP. The rR experiments carried out with isotopically labeled water identified the symmetric and asymmetric vibrations of an Fe-O-Fe unit in the active site at 485 and 780 cm-1, respectively, which was confirmed by the 1.83 Å Fe-O bond observed by XAS. In addition, a unique Fe···O scatterer at 2.82 Å observed from XAS analysis is assigned as arising from the distal O atom of a μ-1,1-peroxo ligand that is bound symmetrically between the irons. The (μ-oxo)(μ-1,1-peroxo)diferric core structure associated with CmlIP is unprecedented among diiron cluster-containing enzymes and corresponding biomimetic complexes. Importantly, it allows the peroxo-diferric intermediate to be ambiphilic, acting as an electrophilic oxidant in the initial N-hydroxylation of an arylamine and then becoming a nucleophilic oxidant in the final oxidation of an aryl-nitroso intermediate to the aryl-nitro product.
Collapse
Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Anna J. Komor
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455
| |
Collapse
|
15
|
Chakov NE, Thuijs AE, Wernsdorfer W, Rheingold AL, Abboud KA, Christou G. Unusual Mn(III/IV)4 Cubane and Mn(III)16M4 (M = Ca, Sr) Looplike Clusters from the Use of Dimethylarsinic Acid. Inorg Chem 2016; 55:8468-77. [PMID: 27504743 DOI: 10.1021/acs.inorgchem.6b01077] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three complexes are reported from the initial use of dimethylarsinic acid (Me2AsO2H) in Mn(III/IV) cluster chemistry, [Mn4O4(O2AsMe2)6] (3; 2Mn(III), 2Mn(IV)), and [Mn16X4O8(O2CPh)16(Me2AsO2)24] (X = Ca(2+) (4) or Sr(2+) (5); 16Mn(III)). They were obtained from reactions with [Mn12O12(O2CR)16(H2O)4] (R = Me, Ph) either without (3) or with (4 and 5) the addition of X(2+) salts. Complex 3 contains a [Mn4O4](6+) cubane, whereas isostructural 4 and 5 contain a planar loop structure comprising four Mn4 asymmetric "butterfly" units linked by alternating anti,anti μ-O2AsMe2 and {X2(O2AsMe2)(O2CPh)2} units. Variable-temperature magnetic susceptibility (χM) data were collected on dried microcrystalline samples of 3-5 in the 5.0-300 K range in a 0.1 T (1000 G) direct-current (dc) magnetic field. Data for 3 were fit to the appropriate Van Vleck equation (using the [Formula: see text] = -2JŜi·Ŝj convention) for a cubane of virtual C2v symmetry, giving J33 = 0.0(1) cm(-1), J34 = -3.4(4) cm(-1), J44 = -9.8(2) cm(-1), and g = 1.99(1), where the Jij subscripts refer to the oxidation states of the interacting Mn atoms. The ground state thus consists of two coupled Mn(IV) and two essentially noninteracting Mn(III). For 4 and 5, low-lying excited states from the high nuclearity and weak couplings prevent fits of dc magnetization data, but in-phase alternating current susceptibility χ'MT data down to 1.8 K indicate them to possess S = 4 ground states, if considered single Mn16 units. If instead they are treated as tetramers of weakly coupled Mn4 units, then each of the latter has an S = 2 ground state. Complexes 4 and 5 also exhibit very weak out-of-phase χ″M signals characteristic of slow relaxation, and magnetization versus dc field scans on a single crystal of 4·15MeCN at T ≥ 0.04 K showed hysteresis loops but with unusual features suggesting the magnetization relaxation barrier consists of more than one contribution.
Collapse
Affiliation(s)
- Nicole E Chakov
- Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States
| | - Annaliese E Thuijs
- Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States
| | | | - Arnold L Rheingold
- Department of Chemistry, University of California at San Diego , La Jolla, California 92093-0358, United States
| | - Khalil A Abboud
- Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States
| | - George Christou
- Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States
| |
Collapse
|
16
|
Jasniewski AJ, Engstrom LM, Vu VV, Park MH, Que L. X-ray absorption spectroscopic characterization of the diferric-peroxo intermediate of human deoxyhypusine hydroxylase in the presence of its substrate eIF5a. J Biol Inorg Chem 2016; 21:605-18. [PMID: 27380180 PMCID: PMC4990465 DOI: 10.1007/s00775-016-1373-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/16/2016] [Indexed: 11/29/2022]
Abstract
Human deoxyhypusine hydroxylase (hDOHH) is an enzyme that is involved in the critical post-translational modification of the eukaryotic translation initiation factor 5A (eIF5A). Following the conversion of a lysine residue on eIF5A to deoxyhypusine (Dhp) by deoxyhypusine synthase, hDOHH hydroxylates Dhp to yield the unusual amino acid residue hypusine (Hpu), a modification that is essential for eIF5A to promote peptide synthesis at the ribosome, among other functions. Purification of hDOHH overexpressed in E. coli affords enzyme that is blue in color, a feature that has been associated with the presence of a peroxo-bridged diiron(III) active site. To gain further insight into the nature of the diiron site and how it may change as hDOHH goes through the catalytic cycle, we have conducted X-ray absorption spectroscopic studies of hDOHH on five samples that represent different species along its reaction pathway. Structural analysis of each species has been carried out, starting with the reduced diferrous state, proceeding through its O2 adduct, and ending with a diferric decay product. Our results show that the Fe⋯Fe distances found for the five samples fall within a narrow range of 3.4-3.5 Å, suggesting that hDOHH has a fairly constrained active site. This pattern differs significantly from what has been associated with canonical dioxygen activating nonheme diiron enzymes, such as soluble methane monooxygenase and Class 1A ribonucleotide reductases, for which the Fe⋯Fe distance can change by as much as 1 Å during the redox cycle. These results suggest that the O2 activation mechanism for hDOHH deviates somewhat from that associated with the canonical nonheme diiron enzymes, opening the door to new mechanistic possibilities for this intriguing family of enzymes.
Collapse
Affiliation(s)
- Andrew J Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Lisa M Engstrom
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Van V Vu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 298-300A Nguyen Tat Thanh Street, Ward 13, District 4, Ho Chi Minh City, Vietnam
| | - Myung Hee Park
- National Institute of Dental and Craniofacial Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA.
| |
Collapse
|
17
|
Han Z, Sakai N, Böttger LH, Klinke S, Hauber J, Trautwein AX, Hilgenfeld R. Crystal Structure of the Peroxo-diiron(III) Intermediate of Deoxyhypusine Hydroxylase, an Oxygenase Involved in Hypusination. Structure 2015; 23:882-892. [PMID: 25865244 DOI: 10.1016/j.str.2015.03.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
Deoxyhypusine hydroxylase (DOHH) is a non-heme diiron enzyme involved in the posttranslational modification of a critical lysine residue of eukaryotic translation initiation factor 5A (eIF-5A) to yield the unusual amino acid residue hypusine. This modification is essential for the role of eIF-5A in translation and in nuclear export of a group of specific mRNAs. The diiron center of human DOHH (hDOHH) forms a peroxo-diiron(III) intermediate (hDOHHperoxo) when its reduced form reacts with O2. hDOHHperoxo has a lifetime exceeding that of the peroxo intermediates of other diiron enzymes by several orders of magnitude. Here we report the 1.7-Å crystal structures of hDOHHperoxo and a complex with glycerol. The structure of hDOHHperoxo reveals the presence of a μ-1,2-peroxo-diiron(III) species at the active site. Augmented by UV/Vis and Mössbauer spectroscopic studies, the crystal structures offer explanations for the extreme longevity of hDOHHperoxo and illustrate how the enzyme specifically recognizes its only substrate, deoxyhypusine-eIF-5A.
Collapse
Affiliation(s)
- Zhenggang Han
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Naoki Sakai
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Lars H Böttger
- Institute of Physics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Sebastián Klinke
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Joachim Hauber
- Heinrich Pette Institute - Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany; German Center for Infection Research (DZIF) c/o Heinrich-Pette-Institute - Leibniz Institute for Experimental Virology, Martinistraße 52, 20251 Hamburg, Germany
| | - Alfred X Trautwein
- Institute of Physics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany; German Center for Infection Research (DZIF) c/o Institute of Biochemistry, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.
| |
Collapse
|
18
|
Makris TM, Vu VV, Meier KK, Komor AJ, Rivard BS, Münck E, Que L, Lipscomb JD. An unusual peroxo intermediate of the arylamine oxygenase of the chloramphenicol biosynthetic pathway. J Am Chem Soc 2015; 137:1608-17. [PMID: 25564306 PMCID: PMC4318726 DOI: 10.1021/ja511649n] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Streptomyces venezuelae CmlI catalyzes the six-electron oxygenation of the arylamine precursor of chloramphenicol in a nonribosomal peptide synthetase (NRPS)-based pathway to yield the nitroaryl group of the antibiotic. Optical, EPR, and Mössbauer studies show that the enzyme contains a nonheme dinuclear iron cluster. Addition of O(2) to the diferrous state of the cluster results in an exceptionally long-lived intermediate (t(1/2) = 3 h at 4 °C) that is assigned as a peroxodiferric species (CmlI-peroxo) based upon the observation of an (18)O(2)-sensitive resonance Raman (rR) vibration. CmlI-peroxo is spectroscopically distinct from the well characterized and commonly observed cis-μ-1,2-peroxo (μ-η(1):η(1)) intermediates of nonheme diiron enzymes. Specifically, it exhibits a blue-shifted broad absorption band around 500 nm and a rR spectrum with a ν(O-O) that is at least 60 cm(-1) lower in energy. Mössbauer studies of the peroxo state reveal a diferric cluster having iron sites with small quadrupole splittings and distinct isomer shifts (0.54 and 0.62 mm/s). Taken together, the spectroscopic comparisons clearly indicate that CmlI-peroxo does not have a μ-η(1):η(1)-peroxo ligand; we propose that a μ-η(1):η(2)-peroxo ligand accounts for its distinct spectroscopic properties. CmlI-peroxo reacts with a range of arylamine substrates by an apparent second-order process, indicating that CmlI-peroxo is the reactive species of the catalytic cycle. Efficient production of chloramphenicol from the free arylamine precursor suggests that CmlI catalyzes the ultimate step in the biosynthetic pathway and that the precursor is not bound to the NRPS during this step.
Collapse
Affiliation(s)
- Thomas M. Makris
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
| | - Van V. Vu
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University,
Pittsburgh, PA 15213, United States
| | - Anna J. Komor
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - Brent S. Rivard
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University,
Pittsburgh, PA 15213, United States
| | - Lawrence Que
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
- Department of Chemistry, University of Minnesota, Minneapolis,
Minnesota 55455, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and
Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of
Minnesota, Minneapolis, MN 55455
| |
Collapse
|
19
|
Abstract
In order to address how diverse metalloprotein active sites, in particular those containing iron and copper, guide O₂binding and activation processes to perform diverse functions, studies of synthetic models of the active sites have been performed. These studies have led to deep, fundamental chemical insights into how O₂coordinates to mono- and multinuclear Fe and Cu centers and is reduced to superoxo, peroxo, hydroperoxo, and, after O-O bond scission, oxo species relevant to proposed intermediates in catalysis. Recent advances in understanding the various factors that influence the course of O₂activation by Fe and Cu complexes are surveyed, with an emphasis on evaluating the structure, bonding, and reactivity of intermediates involved. The discussion is guided by an overarching mechanistic paradigm, with differences in detail due to the involvement of disparate metal ions, nuclearities, geometries, and supporting ligands providing a rich tapestry of reaction pathways by which O₂is activated at Fe and Cu sites.
Collapse
|
20
|
Pap JS, Draksharapu A, Giorgi M, Browne WR, Kaizer J, Speier G. Stabilisation of μ-peroxido-bridged Fe(III) intermediates with non-symmetric bidentate N-donor ligands. Chem Commun (Camb) 2014; 50:1326-9. [PMID: 24343416 DOI: 10.1039/c3cc48196d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The spectroscopic characterisation of the (μ-1,2-peroxido)diiron(iii) species formed transiently upon reaction of [Fe(ii)(NN)3](2+) complexes with H2O2 by UV/vis absorption and resonance Raman spectroscopy is reported. The intermediacy of such species in the disproportionation of H2O2 is demonstrated.
Collapse
Affiliation(s)
- József S Pap
- Department of Chemistry, University of Pannonia, H-8200 Veszprém, Hungary.
| | | | | | | | | | | |
Collapse
|
21
|
Poater A, Chaitanya Vummaleti SV, Cavallo L. The "innocent" role of Sc(3+) on a non-heme Fe catalyst in an O2 environment. Dalton Trans 2014; 43:11190-4. [PMID: 24740434 DOI: 10.1039/c4dt00321g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory calculations have been used to investigate the reaction mechanism proposed for the formation of an oxoiron(iv) complex [Fe(IV)(TMC)O](2+) (P) (TMC = 1,4,8,11-tetramethylcyclam) starting from a non-heme reactant complex [Fe(II)(TMC)](2+) (R) and O2 in the presence of acid H(+) and reductant BPh4(-). We also addressed the possible role of redox-inactive Sc(3+) as a replacement for H(+) acid in this reaction to trigger the formation of P. Our computational results substantially confirm the proposed mechanism and, more importantly, support that Sc(3+) could trigger the O2 activation, mainly dictated by the availability of two electrons from BPh4(-), by forming a thermodynamically stable Sc(3+)-peroxo-Fe(3+) core that facilitates O-O bond cleavage to generate P by reducing the energy barrier. These insights may pave the way to improve the catalytic reactivity of metal-oxo complexes in O2 activation at non-heme centers.
Collapse
Affiliation(s)
- Albert Poater
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Catalonia, Spain.
| | | | | |
Collapse
|
22
|
Stoian SA, Xue G, Bominaar EL, Que L, Münck E. Spectroscopic and theoretical investigation of a complex with an [O═Fe(IV)-O-Fe(IV)═O] core related to methane monooxygenase intermediate Q. J Am Chem Soc 2014; 136:1545-58. [PMID: 24380398 DOI: 10.1021/ja411376u] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Previous efforts to model the diiron(IV) intermediate Q of soluble methane monooxygenase have led to the synthesis of a diiron(IV) TPA complex, 2, with an O=Fe(IV)-O-Fe(IV)-OH core that has two ferromagnetically coupled Sloc = 1 sites. Addition of base to 2 at -85 °C elicits its conjugate base 6 with a novel O═Fe(IV)-O-Fe(IV)═O core. In frozen solution, 6 exists in two forms, 6a and 6b, that we have characterized extensively using Mössbauer and parallel mode EPR spectroscopy. The conversion between 2 and 6 is quantitative, but the relative proportions of 6a and 6b are solvent dependent. 6a has two equivalent high-spin (Sloc = 2) sites, which are antiferromagnetically coupled; its quadrupole splitting (0.52 mm/s) and isomer shift (0.14 mm/s) match those of intermediate Q. DFT calculations suggest that 6a assumes an anti conformation with a dihedral O═Fe-Fe═O angle of 180°. Mössbauer and EPR analyses show that 6b is a diiron(IV) complex with ferromagnetically coupled Sloc = 1 and Sloc = 2 sites to give total spin St = 3. Analysis of the zero-field splittings and magnetic hyperfine tensors suggests that the dihedral O═Fe-Fe═O angle of 6b is ∼90°. DFT calculations indicate that this angle is enforced by hydrogen bonding to both terminal oxo groups from a shared water molecule. The water molecule preorganizes 6b, facilitating protonation of one oxo group to regenerate 2, a protonation step difficult to achieve for mononuclear Fe(IV)═O complexes. Complex 6 represents an intriguing addition to the handful of diiron(IV) complexes that have been characterized.
Collapse
Affiliation(s)
- Sebastian A Stoian
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | | | | | | | | |
Collapse
|
23
|
Pap JS, Cranswick MA, Balogh-Hergovich E, Baráth G, Giorgi M, Rohde GT, Kaizer J, Speier G, Que L. An Iron(II)(1,3-bis(2'-pyridylimino)isoindoline) Complex as a Catalyst for Substrate Oxidation with H 2O 2. Evidence for a Transient Peroxodiiron(III) Species. Eur J Inorg Chem 2013; 2013:3858-3866. [PMID: 24587695 PMCID: PMC3935335 DOI: 10.1002/ejic.201300162] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Indexed: 11/06/2022]
Abstract
The complex [Fe(indH)(solvent)3](ClO4)2 (1) has been isolated from the reaction of equimolar amounts of 1,3-bis(2'-pyridylimino)isoindoline (indH) and Fe(ClO4)2 in acetonitrile and characterized by X-ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H2O2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal-based oxidant. A metastable green species (2) is observed when 1 is reacted with H2O2 at -40 °C, which has been characterized to have a FeIII(μ-O)(μ-O2)FeIII core on the basis of UV-Vis, electron paramagnetic resonance, resonance Raman, and X-ray absorption spectroscopic data.
Collapse
Affiliation(s)
- József S Pap
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Matthew A Cranswick
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
| | - E Balogh-Hergovich
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Gábor Baráth
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Michel Giorgi
- Aix-Marseille Université, FR1739, Spectropole, Campus St. Jérôme, Avenue Escadrille Normandie-Niemen, 13397 Marseille cedex 20, France
| | - Gregory T Rohde
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
| | - József Kaizer
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Gábor Speier
- Department of Chemistry, University of Pannonia, 8201 Veszprém, Wartha Vince u. 1., Hungary
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA
| |
Collapse
|
24
|
Frisch JR, McDonnell R, Rybak-Akimova EV, Que L. Factors affecting the carboxylate shift upon formation of nonheme diiron-O2 adducts. Inorg Chem 2013; 52:2627-36. [PMID: 23432330 DOI: 10.1021/ic302543n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several [Fe(II)2(N-EtHPTB)(μ-O2X)](2+) complexes (1·O2X) have been synthesized, where N-EtHPTB is the anion of N,N,N'N'-tetrakis(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopropane and O2X is an oxyanion bridge. Crystal structures reveal five-coordinate (μ-alkoxo)diiron(II) cores. These diiron(II) complexes react with O2 at low temperatures in CH2Cl2 (-90 °C) to form blue-green O2 adducts that are best described as triply bridged (μ-η(1):η(1)-peroxo)diiron(III) species (2·O2X). With one exception, all 2·O2X intermediates convert irreversibly to doubly bridged, blue (μ-η(1):η(1)-peroxo)diiron(III) species (3·O2X). Where possible, 2·O2X and 3·O2X intermediates were characterized using resonance Raman spectroscopy, showing respective νO-O values of ∼850 and ∼900 cm(-1). How the steric and electronic properties of O2X affect conversion of 2·O2X to 3·O2X was examined. Stopped-flow analysis reveals that oxygenation kinetics of 1·O2X is unaffected by the nature of O2X, and for the first time, the benzoate analog of 2·O2X (2·O2CPh) is observed.
Collapse
Affiliation(s)
- Jonathan R Frisch
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. S.E., Minneapolis, Minnesota 55455, United States
| | | | | | | |
Collapse
|
25
|
Cranswick MA, Meier KK, Shan X, Stubna A, Kaizer J, Mehn MP, Münck E, Que L. Protonation of a peroxodiiron(III) complex and conversion to a diiron(III/IV) intermediate: implications for proton-assisted O-O bond cleavage in nonheme diiron enzymes. Inorg Chem 2012; 51:10417-26. [PMID: 22971084 PMCID: PMC3462276 DOI: 10.1021/ic301642w] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Oxygenation of a diiron(II) complex, [Fe(II)(2)(μ-OH)(2)(BnBQA)(2)(NCMe)(2)](2+) [2, where BnBQA is N-benzyl-N,N-bis(2-quinolinylmethyl)amine], results in the formation of a metastable peroxodiferric intermediate, 3. The treatment of 3 with strong acid affords its conjugate acid, 4, in which the (μ-oxo)(μ-1,2-peroxo)diiron(III) core of 3 is protonated at the oxo bridge. The core structures of 3 and 4 are characterized in detail by UV-vis, Mössbauer, resonance Raman, and X-ray absorption spectroscopies. Complex 4 is shorter-lived than 3 and decays to generate in ~20% yield of a diiron(III/IV) species 5, which can be identified by electron paramagnetic resonance and Mössbauer spectroscopies. This reaction sequence demonstrates for the first time that protonation of the oxo bridge of a (μ-oxo)(μ-1,2-peroxo)diiron(III) complex leads to cleavage of the peroxo O-O bond and formation of a high-valent diiron complex, thereby mimicking the steps involved in the formation of intermediate X in the activation cycle of ribonucleotide reductase.
Collapse
Affiliation(s)
- Matthew A. Cranswick
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Katlyn K. Meier
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Xiaopeng Shan
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Audria Stubna
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Jószef Kaizer
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Mark P. Mehn
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| |
Collapse
|
26
|
Do LH, Wang H, Tinberg CE, Dowty E, Yoda Y, Cramer SP, Lippard SJ. Characterization of a synthetic peroxodiiron(III) protein model complex by nuclear resonance vibrational spectroscopy. Chem Commun (Camb) 2011; 47:10945-7. [PMID: 21897991 DOI: 10.1039/c1cc13836g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The vibrational spectrum of an η(1),η(1)-1,2-peroxodiiron(III) complex was measured by nuclear resonance vibrational spectroscopy and fit using an empirical force field analysis. Isotopic (18)O(2) labelling studies revealed a feature involving motion of the {Fe(2)(O(2))}(4+) core that was not previously observed by resonance Raman spectroscopy.
Collapse
Affiliation(s)
- Loi H Do
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | | | | | | | | | | | | |
Collapse
|
27
|
Mukherjee A, Cranswick MA, Chakrabarti M, Paine TK, Fujisawa K, Münck E, Que L. Oxygen activation at mononuclear nonheme iron centers: a superoxo perspective. Inorg Chem 2010; 49:3618-28. [PMID: 20380464 DOI: 10.1021/ic901891n] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dioxygen (O(2)) activation by iron enzymes is responsible for many metabolically important transformations in biology. Often a high-valent iron oxo oxidant is proposed to form upon O(2) activation at a mononuclear nonheme iron center, presumably via intervening iron superoxo and iron peroxo species. While iron(IV) oxo intermediates have been trapped and characterized in enzymes and models, less is known of the putative iron(III) superoxo species. Utilizing a synthetic model for the 2-oxoglutarate-dependent monoiron enzymes, [(Tp(iPr2))Fe(II)(O(2)CC(O)CH(3))], we have obtained indirect evidence for the formation of the putative iron(III) superoxo species, which can undergo one-electron reduction, hydrogen-atom transfer, or conversion to an iron(IV) oxo species, depending on the reaction conditions. These results demonstrate the various roles that the iron(III) superoxo species can play in the course of O(2) activation at a nonheme iron center.
Collapse
Affiliation(s)
- Anusree Mukherjee
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | | | |
Collapse
|