1
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Bohn A, Robinson AL, Sénéchal-David K, Herrero C, Kanoufi F, Anxolabéhère-Mallart E, Banse F. Electrochemical approach of the reductive activation of O 2 by a nonheme Fe II complex. Some clues for the development of catalytic oxidations. Dalton Trans 2024. [PMID: 39246009 DOI: 10.1039/d4dt01870b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024]
Abstract
We report an in-depth study of the reductive activation of O2 by the nonheme [FeII(L25)(MeCN)]2+ complex carried out by cyclic voltammetry. Experimental evidence is obtained for the slow coordination of dioxygen to the ferrous center yielding an FeII/O2 adduct with a strong FeII-O2 character rather than an FeIII-superoxo one. Electron injection in the FeII-O2 species occurs at a potential of ca. -700 mV vs. SCE, i.e. 200 mV above the O2 to O2˙- reduction, leading to the formation of a FeIII-peroxo intermediate and then FeIII-hydroperoxo upon protonation by residual water. The experimental CVs recorded at variable scan rate or variable FeII concentration are well simulated taking into account a detailed mechanism initiated by the competitive reduction of O2 and the FeII-O2 adduct. Analysis of the concentration of the reaction intermediates generated as a function of the applied potential indicates that the FeIII-peroxo intermediate significantly accumulates at a potential of -650 mV. Oxidative bromination of anisole is assayed under electrolytic conditions at this potential to yield bromoanisole products. The low faradaic yields observed reveal that deleterious reactions such as direct reduction of reaction intermediates likely occur. Based on the detailed mechanism elucidated, a number of improvements to achieve more efficient catalytic reactions can be proposed.
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Affiliation(s)
- Antoine Bohn
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400, Orsay, France.
| | - Amanda Lyn Robinson
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400, Orsay, France.
| | - Katell Sénéchal-David
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400, Orsay, France.
| | - Christian Herrero
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400, Orsay, France.
| | - Frédéric Kanoufi
- Interfaces, Traitements, Organisation et Dynamique des Systèmes, Université de Paris, CNRS, F-75013 Paris, France
| | | | - Frédéric Banse
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay, 91400, Orsay, France.
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2
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Wang Y, Liu Y. Computational Insights into the Non-Heme Diiron Alkane Monooxygenase Enzyme AlkB: Electronic Structures, Dioxygen Activation, and Hydroxylation Mechanism of Liquid Alkanes. Inorg Chem 2024. [PMID: 39238331 DOI: 10.1021/acs.inorgchem.4c02721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Abstract
Alkane monooxygenase (AlkB) is a membrane-spanning metalloenzyme that catalyzes the terminal hydroxylation of straight-chain alkanes involved in the microbially mediated degradation of liquid alkanes. According to the cryoEM structures, AlkB features a unique multihistidine ligand coordination environment with a long Fe-Fe distance in its active center. Up to now, how AlkB employs the diiron center to activate dioxygen and which species is responsible for triggering the hydroxylation are still elusive. In this work, we constructed computational models and performed quantum mechanics/molecular mechanics (QM/MM) calculations to illuminate the electronic characteristics of the diiron active center and how AlkB carries out the terminal hydroxylation. Our calculations revealed that the spin-spin interaction between two irons is rather weak. The dioxygen may ligate to either the Fe1 or Fe2 atom and prefers to act as a linker to increase the spin-spin interaction of two irons, facilitating the dioxygen cleavage to generate the highly reactive Fe(IV)═O. Thus, AlkB employs Fe(IV)═O to trigger the hydrogen abstraction. In addition, the previously suggested mechanism that AlkB uses both the dioxygen and Fe-coordinated water to perform hydroxylation was calculated to be unlikely. Besides, our results indicate that AlkB cannot use the Fe-coordinated dioxygen to directly trigger hydrogen abstraction.
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Affiliation(s)
- Yue Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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3
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Török P, Lakk-Bogáth D, Unjaroen D, Browne WR, Kaizer J. Effect of monodentate heterocycle co-ligands on the μ-1,2-peroxo-diiron(III) mediated aldehyde deformylation reactions. J Inorg Biochem 2024; 258:112620. [PMID: 38824901 DOI: 10.1016/j.jinorgbio.2024.112620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/17/2024] [Accepted: 05/25/2024] [Indexed: 06/04/2024]
Abstract
Peroxo-diiron(III) species are present in the active sites of many metalloenzymes that carry out challenging organic transformations. The reactivity of these species is influenced by various factors, such as the structure and topology of the supporting ligands, the identity of the axial and equatorial co-ligands, and the oxidation states of the metal ion(s). In this study, we aim to diversify the importance of equatorial ligands in controlling the reactivity of peroxo-diiron(III) species. As a model compound, we chose the previously published and fully characterized [(PBI)2(CH3CN)FeIII(μ-O2)FeIII(CH3CN)(PBI)2]4+ complex, where the steric effect of the four PBI ligands is minimal, so the labile CH3CN molecules easily can be replaced by different monodentate co-ligands (substituted pyridines and N-donor heterocyclic compounds). Thus, their effect on the electronic and spectral properties of peroxo-divas(III) intermediates could be easily investigated. The relationship between structure and reactivity was also investigated in the stoichiometric deformylation of PPA mediated by peroxo-diiron(III) complexes. It was found that the deformylation rates are influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the FeIII/FeII redox potentials (in the range of 197 to 415 mV).
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Affiliation(s)
- Patrik Török
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Dóra Lakk-Bogáth
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Duenpen Unjaroen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - 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, Universtiy of Pannonia, 8201 Veszprém, Hungary.
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4
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Schneider JE, Zeng S, Anferov SW, Filatov AS, Anderson JS. Isolation and Crystallographic Characterization of an Octavalent Co 2O 2 Diamond Core. J Am Chem Soc 2024; 146:23998-24008. [PMID: 39146525 DOI: 10.1021/jacs.4c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
High-valent cobalt oxides play a pivotal role in alternative energy technology as catalysts for water splitting and as cathodes in lithium-ion batteries. Despite this importance, the properties governing the stability of high-valent cobalt oxides and specifically possible oxygen evolution pathways are not clear. One root of this limited understanding is the scarcity of high-valent Co(IV)-containing model complexes; there are no reports of stable, well-defined complexes with multiple Co(IV) centers. Here, an oxidatively robust fluorinated ligand scaffold enables the isolation and crystallographic characterization of a Co(IV)2-bis-μ-oxo complex. This complex is remarkably stable, in stark contrast with previously reported Co(IV)2 species that are highly reactive, which demonstrates that oxy-Co(IV)2 species are not necessarily unstable with respect to oxygen evolution. This example underscores a new design strategy for highly oxidizing transition-metal fragments and provides detailed data on a previously inaccessible chemical unit of relevance to O-O bond formation and oxygen evolution.
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Affiliation(s)
- Joseph E Schneider
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Shilin Zeng
- 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
| | - 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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5
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Nguyen N, Forstater JH, McIntosh JA. Decarboxylation in Natural Products Biosynthesis. JACS AU 2024; 4:2715-2745. [PMID: 39211618 PMCID: PMC11350588 DOI: 10.1021/jacsau.4c00425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 09/04/2024]
Abstract
Decarboxylation reactions are frequently found in the biosynthesis of primary and secondary metabolites. Decarboxylase enzymes responsible for these transformations operate via diverse mechanisms and act on a large variety of substrates, making them appealing in terms of biotechnological applications. This Perspective focuses on the occurrence of decarboxylation reactions in natural product biosynthesis and provides a perspective on their applications in biocatalysis for fine chemicals and pharmaceuticals.
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6
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Gravogl L, Keilwerth M, Körber E, Heinemann FW, Meyer K. From d 8 to d 1: Iron(0) and Iron(I) Complexes Complete the Series of Eight Fe Oxidation States within the TIMMN Mes Ligand Framework. Inorg Chem 2024; 63:15888-15905. [PMID: 39145894 DOI: 10.1021/acs.inorgchem.4c02129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Reduction of the ferrous precursor [(TIMMNMes)Fe(Cl)]+ (1) (TIMMNMes = tris-[(3-mesitylimidazol-2-ylidene)methyl]amine) to the low-valent iron(0) complex [(TIMMNMes)Fe(CO)3] (2) is presented, where the tris(N-heterocyclic carbene) (NHC) ligand framework remains intact, yet the coordination mode changed from 3-fold to 2-fold coordination of the carbene arms. Further, the corresponding iron(I) complexes [(TIMMNMes)Fe(L)]+ (L = free site, η1-N2, CO, py) (3) are synthesized and fully characterized. Complexes 1-3 demonstrate the notable steric and electronic flexibility of the TIMMNMes ligand framework by variation of the Fe-N anchor and Fe-carbene distances and the variable size of the axial cavity occupation. This is further underpinned by the oxidation of 3-N2 in a reaction with benzophenone to yield the corresponding, charge-separated iron(II) radical complex [(TIMMNMes)Fe(OCPh2)]+ (4). We found rather surprising similarities in the reactivity behavior when going to low- or high-valent oxidation states of the central iron ion. This is demonstrated by the closely related reactivity of 3-N2, where H atom abstraction with TEMPO triggers the formation of the metallacycle [(TIMMNMes*)Fe(py)]+ (5), and the reactivity of the highly unstable Fe(VII) nitride complex [(TIMMNMes)Fe(N)(F)]3+ to give the metallacyclic Fe(V) imido complex [(TIMMNMesN)Fe(NMes)(MeCN)]3+ (6) upon warming. Thus, the employed tris(carbene) chelate is not only capable of stabilizing the superoxidized Fe(VI) and Fe(VII) nitrides but equally supports the iron center in its low oxidation states 0 and +1. Isolation and characterization of these zero- and monovalent iron complexes demonstrate the extraordinary capability of the tris(carbene) chelate TIMMN to support iron in eight different oxidation states within the very same ligand platform.
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Affiliation(s)
- Lisa Gravogl
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Eva Körber
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
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7
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Menezes L, Sampaio RMSN, Meurer L, Szpoganicz B, Cervo R, Cargnelutti R, Wang L, Yang J, Prabhakar R, Fernandes C, Horn A. A Multipurpose Metallophore and Its Copper Complexes with Diverse Catalytic Antioxidant Properties to Deal with Metal and Oxidative Stress Disorders: A Combined Experimental, Theoretical, and In Vitro Study. Inorg Chem 2024; 63:14827-14850. [PMID: 39078252 PMCID: PMC11323273 DOI: 10.1021/acs.inorgchem.4c00232] [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: 01/18/2024] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 07/31/2024]
Abstract
We report the discovery that the molecule 1-(pyridin-2-ylmethylamino)propan-2-ol (HL) can reduce oxidative stress in neuronal C6 glioma cells exposed to reactive oxygen species (O2-•, H2O2, and •OH) and metal (Cu+) stress conditions. Furthermore, its association with Cu2+ generates [Cu(HL)Cl2] (1) and [Cu(HL)2](ClO4)2 (2) complexes that also exhibit antioxidant properties. Potentiometric titration data show that HL can coordinate to Cu2+ in 1:1 and 1:2 Cu2+:ligand ratios, which was confirmed by monocrystal X-ray studies. The subsequent ultraviolet-visible, electrospray ionization mass spectrometry, and electron paramagnetic resonance experiments show that they can decompose a variety of reactive oxygen species (ROS). Kinetic studies revealed that 1 and 2 mimic the superoxide dismutase and catalase activities. Complex 1 promotes the fastest decomposition of H2O2 (kobs = 2.32 × 107 M-1 s-1), efficiently dismutases the superoxide anion (kcat = 3.08 × 107 M-1 s-1), and scavenges the hydroxyl radical (RSA50 = 25.7 × 10-6 M). Density functional theory calculations support the formation of dinuclear Cu-peroxide and mononuclear Cu-superoxide species in the reactions of [Cu(HL)Cl2] with H2O2 and O2•-, respectively. Furthermore, both 1 and 2 also reduce the oxidative stress of neuronal glioma C6 cells exposed to different ROS, including O2•- and •OH.
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Affiliation(s)
- Lucas
B. Menezes
- Departamento
de Química, Universidade Federal
de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Raquel M. S. N. Sampaio
- Laboratório
de Ciências Químicas, Universidade
Estadual do Norte Fluminense Darcy Ribeiro, 28013-602 Campos dos Goytacazes, RJ, Brazil
| | - Lino Meurer
- Departamento
de Química, Universidade Federal
de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Bruno Szpoganicz
- Departamento
de Química, Universidade Federal
de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Rodrigo Cervo
- Departamento
de Química, Universidade Federal
de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Roberta Cargnelutti
- Departamento
de Química, Universidade Federal
de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Lukun Wang
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Jiawen Yang
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Rajeev Prabhakar
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Christiane Fernandes
- Departamento
de Química, Universidade Federal
de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Adolfo Horn
- Departamento
de Química, Universidade Federal
de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
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8
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Ramakrishnan S, Anjukandi P. Superoxide to Peroxide Interconversion in Ni-TMC Complexes: The Significance of Structure and Spin States. Inorg Chem 2024; 63:15186-15196. [PMID: 39072391 DOI: 10.1021/acs.inorgchem.4c02568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
A deeper comprehension of the characteristics of metal-superoxide and metal-peroxide chemical species is imperative, considering their pivotal functions in oxygen transport, enzymatic activation, and catalytic oxygenations. O2 activation is mediated by the interconversion of superoxide and peroxide species. Even though there are multiple studies on metal-superoxide and -peroxide intermediates, robust examples of their interconversion processes are scarce synthetically. For example, Ni-superoxide/peroxide complexes have been characterized with N-Tetramethylated Cyclam (TMC) ligands with different ring sizes, i.e., Nickel(II)-superoxide complex is characterized with 14-TMC while Nickel(III)-peroxide complex with 12-TMC. Later, both complexes were obtained with 13-TMC ligand by employing different bases; interestingly, no evidence of interconversion between them was identified. What are the factors influencing these processes and why is this preference? We attempt a computational analysis of this issue and provide arguments based on our conclusions. 2-dimensional potential energy scan is performed on the 12-TMC, 13-TMC, and 14-TMC systems to identify the reaction path connecting superoxide and peroxide species. Analyses indicate that structure and spin states play a significant role in determining the probability of interconversion. The superoxide-peroxide interconversion process appears to be bound by their propensity for distinct structural features and spin states.
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Affiliation(s)
- Shyama Ramakrishnan
- Department of Chemistry, Indian Institute of Technology, Kanjikode, Palakkad, Kerala 678623, India
| | - Padmesh Anjukandi
- Department of Chemistry, Indian Institute of Technology, Kanjikode, Palakkad, Kerala 678623, India
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9
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Spielvogel KD, Campbell EJ, Chowdhury SR, Benner F, Demir S, Hatzis GP, Petras HR, Sembukuttiarachchige D, Shepherd JJ, Thomas CM, Vlaisavljevich B, Daly SR. Modulation of Fe-Fe distance and spin in diiron complexes using tetradentate ligands with different flanking donors. Chem Commun (Camb) 2024; 60:8399-8402. [PMID: 39028006 DOI: 10.1039/d4cc02522a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Here we report the synthesis and characterization of diiron complexes containing triaryl N4 and N2S2 ligands derived from o-phenylenediamine. The complexes display significant differences in Fe-Fe distances and magnetic properties that depend on the identity of the flanking NMe2 and SMe donor groups.
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Affiliation(s)
- Kyle D Spielvogel
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Emily J Campbell
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Sabyasachi Roy Chowdhury
- The University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA
| | - Florian Benner
- Michigan State University, Department of Chemistry, 578 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Selvan Demir
- Michigan State University, Department of Chemistry, 578 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Gillian P Hatzis
- The Ohio State University, Department of Chemistry and Biochemistry, 100 West 18th Ave, Columbus, OH 43210, USA
| | - Hayley R Petras
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | | | - James J Shepherd
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Christine M Thomas
- The Ohio State University, Department of Chemistry and Biochemistry, 100 West 18th Ave, Columbus, OH 43210, USA
| | - Bess Vlaisavljevich
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
- The University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA
| | - Scott R Daly
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
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10
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Kornowicz A, Pietrzak T, Korona K, Terlecki M, Justyniak I, Kubas A, Lewiński J. Fresh Impetus in the Chemistry of Calcium Peroxides. J Am Chem Soc 2024; 146:18938-18947. [PMID: 38847558 PMCID: PMC11258691 DOI: 10.1021/jacs.4c00906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 05/22/2024] [Accepted: 05/22/2024] [Indexed: 07/18/2024]
Abstract
Redox-inactive metal ions are essential in modulating the reactivity of various oxygen-containing metal complexes and metalloenzymes, including photosystem II (PSII). The heart of this unique membrane-protein complex comprises the Mn4CaO5 cluster, in which the Ca2+ ion acts as a critical cofactor in the splitting of water in PSII. However, there is still a lack of studies involving Ca-based reactive oxygen species (ROS) systems, and the exact nature of the interaction between the Ca2+ center and ROS in PSII still generates intense debate. Here, harnessing a novel Ca-TEMPO complex supported by the β-diketiminate ligand to control the activation of O2, we report the isolation and structural characterization of hitherto elusive Ca peroxides, a homometallic Ca hydroperoxide and a heterometallic Ca/K peroxide. Our studies indicate that the presence of K+ cations is a key factor controlling the outcome of the oxygenation reaction of the model Ca-TEMPO complex. Combining experimental observations with computational investigations, we also propose a mechanistic rationalization for the reaction outcomes. The designed approach demonstrates metal-TEMPO complexes as a versatile platform for O2 activation and advances the understanding of Ca/ROS systems.
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Affiliation(s)
- Arkadiusz Kornowicz
- Institute
of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Tomasz Pietrzak
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Krzesimir Korona
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Michał Terlecki
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Iwona Justyniak
- Institute
of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Adam Kubas
- Institute
of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Janusz Lewiński
- Institute
of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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11
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Kayne M, Murphy PS, Kwon YM, Lee Y, Jackson TA, Wang D. Generation, Characterization and Reactivity of a High-Valent Mononuclear Cobalt(IV)-Diazide Complex. Chemistry 2024; 30:e202401218. [PMID: 38644346 DOI: 10.1002/chem.202401218] [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: 04/17/2024] [Accepted: 04/20/2024] [Indexed: 04/23/2024]
Abstract
High-valent Fe(IV)=O intermediates of metalloenzymes have inspired numerous efforts to generate synthetic analogs to mimic and understand their substrate oxidation reactivities. However, high-valent M(IV) complexes of late transition metals are rare. We have recently reported a novel Co(IV)-dinitrate complex (1-NO3) that activates sp3 C-H bonds up to 87 kcal/mol. In this work, we have shown that the nitrate ligands in 1-NO3 can be replaced by azide, a more basic coordinating base, resulting in the formation of a more potent Co(IV)-diazide species (1-N3) that reacts with substrates (hydrocarbons and phenols) at faster rate constants and activates stronger C-H bonds than the parent complex 1-NO3. We have characterized 1-N3 employing a combination of spectroscopic and computational approaches. Our results clearly show that the coordination of azide leads to the modulation of the Co(IV) electronic structure and the Co(IV/III) redox potential. Together with the higher basicity of azide, these thermodynamic parameters contribute to the higher driving forces of 1-N3 than 1-NO3 for C-H bond activation. Our discoveries are thus insightful for designing more reactive bio-inspired high-valent late transition metal complexes for activating inert aliphatic hydrocarbons.
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Affiliation(s)
- Michael Kayne
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Patrick S Murphy
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, Kansas, 66045, United States
| | - Yubin M Kwon
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, 59812, United States
| | - Yuri Lee
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, Kansas, 66045, United States
| | - Timothy A Jackson
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, Kansas, 66045, United States
| | - Dong Wang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana, 59812, United States
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12
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Depenbrock F, Limpke T, Stammler A, Oldengott J, Bögge H, Glaser T. Increasing the electron donation in a dinucleating ligand family: molecular and electronic structures in a series of Co IICo II complexes. Dalton Trans 2024; 53:9554-9567. [PMID: 38771300 DOI: 10.1039/d4dt00877d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
We have developed a family of dinucleating ligands with varying terminal donors to generate dinuclear peroxo and high-valent complexes and to correlate their stabilities and reactivities with their molecular and electronic structures as a function of the terminal donors. It appears that the electron-donating ability of the terminal donors is an important handle for controlling these stabilities and reactivities. Here, we present the synthesis of a new dinucleating ligand with potentially strong donating terminal imidazole donors. As CoII ions are sensitive to variations in donor strength in terms of coordination number, magnetism, UV-Vis-NIR spectra, redox potentials, we probe the electron donation ability of this new ligand in CoIICoII complexes in comparison to the parent CoIICoII complexes with terminal pyridine donors and we synthesize the analogous CoIICoII complexes with terminal 6-methylpyridines and methoxy-substituted pyridines. The molecular structures show indeed strong variations in coordination numbers and bond lengths. These differences in the molecular structures are reflected in the magnetic properties and in the d-d transitions demonstrating that the molecular structures remain intact upon dissolution. The redox potentials are analyzed with respect to the electron donation ability and are the only handle to observe an effect of the methoxy-substituted pyridines. All data taken together show the following order of electron donating ability for the terminal donors: 6-methylpyridines ≪ pyridines < methoxy-substituted pyridines ≪ imidazoles.
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Affiliation(s)
- Felix Depenbrock
- 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.
| | - Jan Oldengott
- 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.
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
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13
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Chen JY, van der Donk WA. Multinuclear non-heme iron dependent oxidative enzymes (MNIOs) involved in unusual peptide modifications. Curr Opin Chem Biol 2024; 80:102467. [PMID: 38772214 DOI: 10.1016/j.cbpa.2024.102467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/23/2024]
Abstract
Multinuclear non-heme iron dependent oxidative enzymes (MNIOs), formerly known as domain of unknown function 692 (DUF692), are involved in the post-translational modification of peptides during the biosynthesis of peptide-based natural products. These enzymes catalyze highly unusual and diverse chemical modifications. Several class-defining features of this large family (>14 000 members) are beginning to emerge. Structurally, the enzymes are characterized by a TIM-barrel fold and a set of conserved residues for a di- or tri-iron binding site. They use molecular oxygen to modify peptide substrates, often in a four-electron oxidation taking place at a cysteine residue. This review summarizes the current understanding of MNIOs. Four modifications are discussed in detail: oxazolone-thioamide formation, β-carbon excision, hydantoin-macrocycle formation, and 5-thiooxazole formation. Briefly discussed are two other reactions that do not take place on Cys residues.
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Affiliation(s)
- Jeff Y Chen
- Department of Chemistry, The Carl R. Woese Institute for Genomic Biology, The Howard Hughes Medical Institute at the University of Illinois at Urbana-Champaign, 1206 W Gregory Drive, Urbana, IL 61801, USA
| | - Wilfred A van der Donk
- Department of Chemistry, The Carl R. Woese Institute for Genomic Biology, The Howard Hughes Medical Institute at the University of Illinois at Urbana-Champaign, 1206 W Gregory Drive, Urbana, IL 61801, USA.
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14
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Juda CE, Handford RC, Bartholomew AK, Powers TM, Gu NX, Meyer E, Roth N, Chen YS, Zheng SL, Betley TA. Cluster dynamics of heterometallic trinuclear clusters during ligand substitution, redox chemistry, and group transfer processes. Chem Sci 2024; 15:8242-8248. [PMID: 38817579 PMCID: PMC11134326 DOI: 10.1039/d3sc03606e] [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: 07/13/2023] [Accepted: 02/04/2024] [Indexed: 06/01/2024] Open
Abstract
Stepwise metalation of the hexadentate ligand tbsLH6 (tbsLH6 = 1,3,5-C6H9(NHC6H4-o-NHSiMe2tBu)3) affords bimetallic trinuclear clusters (tbsL)Fe2Zn(thf) and (tbsL)Fe2Zn(py). Reactivity studies were pursued to understand metal atom lability as the clusters undergo ligand substitution, redox chemistry, and group transfer processes. Chloride addition to (tbsL)Fe2Zn(thf) resulted in a mixture of species including both all-zinc and all-iron products. Addition of ArN3 (Ar = Ph, 3,5-(CF3)2C6H3) to (tbsL)Fe2Zn(py) yielded a mixture of two trinuclear products: (tbsL)Fe3(μ3-NAr) and (tbsL)Fe2Zn(μ3-NAr)(py). The two imido species were separated via crystallization, and outer sphere reduction of (tbsL)Fe2Zn(μ3-NAr)(py) resulted in the formation of a single product, [2,2,2-crypt(K)][(tbsL)Fe2Zn(μ3-NAr)]. These results provide insight into the relationship between heterometallic cluster structure and substitutional lability and could help inform both future catalyst design and our understanding of metal atom lability in bioinorganic systems.
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Affiliation(s)
- Cristin E Juda
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Rex C Handford
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | | | - Tamara M Powers
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Nina X Gu
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Elisabeth Meyer
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Nikolaj Roth
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Yu-Sheng Chen
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University Cambridge MA 02139 USA
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15
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Sen A, Britto NJ, Kass D, Ray K, Rajaraman G. Origin of Unprecedented Formation and Reactivity of Fe IV═O Species via Oxygen Activation: Role of Noncovalent Interactions and Magnetic Coupling. Inorg Chem 2024; 63:9809-9822. [PMID: 38739843 DOI: 10.1021/acs.inorgchem.4c00371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Emulating the capabilities of the soluble methane monooxygenase (sMMO) enzymes, which effortlessly activate oxygen at diiron(II) centers to form a reactive diiron(IV) intermediate Q, which then performs the challenging oxidation of methane to methanol, poses a significant challenge. Very recently, one of us reported the mononuclear complex [(cyclam)FeII(CH3CN)2]2+ (1), which performed a rare bimolecular activation of the molecule of O2 to generate two molecules of FeIV═O without the requirement of external proton or electron sources, similar to sMMO. In the present study, we employed the density functional theory (DFT) calculations to investigate this unique mechanism of O2 activation. We show that secondary hydrogen-bonding interactions between ligand N-H groups and O2 play a vital role in reducing the energy barrier associated with the initial O2 binding at 1 and O-O bond cleavage to form the FeIV═O complex. Further, the unique reactivity of FeIV═O species toward simultaneous C-H and O-H bond activation process has been demonstrated. Our study unveils that the nature of the magnetic coupling between the diiron centers is also crucial. Given that the influence of magnetic coupling and noncovalent interactions in catalysis remains largely unexplored, this unexplored realm presents numerous avenues for experimental chemists to develop novel structural and functional analogues of sMMO.
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Affiliation(s)
- Asmita Sen
- Department of Chemistry, IIT Bombay, Powai, Mumbai-400076, India
| | | | - Dustin Kass
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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16
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Fagnano A, Frateloreto F, Paoloni R, Sappino C, Lanzalunga O, Costas M, Di Stefano S, Olivo G. Proximity Effects on the Reactivity of a Nonheme Iron (IV) Oxo Complex in C-H Oxidation. Angew Chem Int Ed Engl 2024; 63:e202401694. [PMID: 38478739 DOI: 10.1002/anie.202401694] [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: 01/24/2024] [Indexed: 04/05/2024]
Abstract
Precise control of substrate positioning and orientation (its proximity to the reactive unit) is often invoked to rationalize the superior enzymatic reaction rates and selectivities when compared to synthetic models. Artificial nonheme iron (IV) oxo (Fe(IV)=O) complexes react with C(sp3)-H bonds via a biomimetic Hydrogen Atom Transfer/Hydroxyl Rebound mechanism, but rates, site-selectivity and even hydroxyl rebound efficiency (ligand rebound versus substrate radical diffusion) are smaller than in oxygenases. Herein, we quantitatively analyze how substrate binding modulates nonheme Fe(IV)=O reactivity by comparing rates and outcomes of C-H oxidation by a pair of Fe(IV)=O complexes that share the same first coordination sphere but only one contains a crown ether receptor that recognizes the substrate. Substrate binding makes the reaction intramolecular, exhibiting Michaelis-Menten kinetics and increased reaction rates. In addition, C-H oxidation occurs with high site selectivity for remote sites. Analysis of Effective Molarity reveals that the system operates at its maximal theoretical capability for the oxidation of these remote sites. Remarkably, substrate positioning also affects Hydroxyl Rebound, whose efficiency only increases on the sites placed in proximity by recognition. Overall, these observations provide evidence that supramolecular control of substrate positioning can effectively modulate the reactivity of oxygenases and its models.
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Affiliation(s)
- Alessandro Fagnano
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Federico Frateloreto
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Roberta Paoloni
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Carla Sappino
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Miquel Costas
- QBIS-Cat, Institut de Química Computacional i Catàlisi (IQCC), Departament de Quimica, Universitat de Girona Campus Montilivi, 17071, Girona, Catalonia, Spain
| | - Stefano Di Stefano
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
| | - Giorgio Olivo
- Dipartimento di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma "La Sapienza", P.le A. Moro, 5 I-00185, Rome, Italy
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17
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Jodts RJ, Ho MB, Reyes RM, Park YJ, Doan PE, Rosenzweig AC, Hoffman BM. Initial Steps in Methanobactin Biosynthesis: Substrate Binding by the Mixed-Valent Diiron Enzyme MbnBC. Biochemistry 2024; 63:1170-1177. [PMID: 38587906 DOI: 10.1021/acs.biochem.4c00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The MbnBC enzyme complex converts cysteine residues in a peptide substrate, MbnA, to oxazolone/thioamide groups during the biosynthesis of copper chelator methanobactin (Mbn). MbnBC belongs to the mixed-valent diiron oxygenase (MVDO) family, of which members use an Fe(II)Fe(III) cofactor to react with dioxygen for substrate modification. Several crystal structures of the inactive Fe(III)Fe(III) form of MbnBC alone and in complex with MbnA have been reported, but a mechanistic understanding requires determination of the oxidation states of the crystallographically observed Fe ions in the catalytically active Fe(II)Fe(III) state, along with the site of MbnA binding. Here, we have used electron nuclear double resonance (ENDOR) spectroscopy to determine such structural and electronic properties of the active site, in particular, the mode of substrate binding to the MV state, information not accessible by X-ray crystallography alone. The oxidation states of the two Fe ions were determined by 15N ENDOR analysis. The presence and locations of both bridging and terminal exogenous solvent ligands were determined using 1H and 2H ENDOR. In addition, 2H ENDOR using an isotopically labeled MbnA substrate indicates that MbnA binds to the Fe(III) ion of the cluster via the sulfur atom of its N-terminal modifiable cysteine residue, with displacement of a coordinated solvent ligand as shown by complementary 1H ENDOR. These results, which underscore the utility of ENDOR in studying MVDOs, provide a molecular picture of the initial steps in Mbn biosynthesis.
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18
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Ferizhendi KK, Simon P, Pelosi L, Séchet E, Arulanandam R, Chehade MH, Rey M, Onal D, Flandrin L, Chreim R, Faivre B, Vo SCDT, Arias-Cartin R, Barras F, Fontecave M, Bouveret E, Lombard M, Pierrel F. An organic O donor for biological hydroxylation reactions. Proc Natl Acad Sci U S A 2024; 121:e2321242121. [PMID: 38507448 PMCID: PMC10990095 DOI: 10.1073/pnas.2321242121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 02/08/2024] [Indexed: 03/22/2024] Open
Abstract
All biological hydroxylation reactions are thought to derive the oxygen atom from one of three inorganic oxygen donors, O2, H2O2, or H2O. Here, we have identified the organic compound prephenate as the oxygen donor for the three hydroxylation steps of the O2-independent biosynthetic pathway of ubiquinone, a widely distributed lipid coenzyme. Prephenate is an intermediate in the aromatic amino acid pathway and genetic experiments showed that it is essential for ubiquinone biosynthesis in Escherichia coli under anaerobic conditions. Metabolic labeling experiments with 18O-shikimate, a precursor of prephenate, demonstrated the incorporation of 18O atoms into ubiquinone. The role of specific iron-sulfur enzymes belonging to the widespread U32 protein family is discussed. Prephenate-dependent hydroxylation reactions represent a unique biochemical strategy for adaptation to anaerobic environments.
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Affiliation(s)
| | - Philippe Simon
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Ludovic Pelosi
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble38000, France
| | - Emmanuel Séchet
- SAMe Unit, Département de Microbiologie, Institut Pasteur, Université Paris-Cité, UMR CNRS 6047, ParisF-75015, France
| | - Roache Arulanandam
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Mahmoud Hajj Chehade
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble38000, France
| | - Martial Rey
- Institut Pasteur, Université Paris Cité, CNRS UAR2024, Mass Spectrometry for Biology, ParisF-75015, France
| | - Deniz Onal
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Laura Flandrin
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble38000, France
| | - Rouba Chreim
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble38000, France
| | - Bruno Faivre
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Samuel Chau-Duy-Tam Vo
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Rodrigo Arias-Cartin
- SAMe Unit, Département de Microbiologie, Institut Pasteur, Université Paris-Cité, UMR CNRS 6047, ParisF-75015, France
| | - Frédéric Barras
- SAMe Unit, Département de Microbiologie, Institut Pasteur, Université Paris-Cité, UMR CNRS 6047, ParisF-75015, France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Emmanuelle Bouveret
- SAMe Unit, Département de Microbiologie, Institut Pasteur, Université Paris-Cité, UMR CNRS 6047, ParisF-75015, France
| | - Murielle Lombard
- Laboratoire de Chimie des Processus Biologiques, Institut de Chimie, Collège de France, CNRS UMR 8229, PSL Research University, Sorbonne Université, Paris75005, France
| | - Fabien Pierrel
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble38000, France
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19
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Chandra B, Ahsan F, Sheng Y, Swart M, Que L. A tale of two topological isomers: Uptuning [Fe IV(O)(Me 4cyclam)] 2+ for olefin epoxidation. Proc Natl Acad Sci U S A 2024; 121:e2319799121. [PMID: 38478690 PMCID: PMC10962992 DOI: 10.1073/pnas.2319799121] [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: 11/15/2023] [Accepted: 01/30/2024] [Indexed: 03/27/2024] Open
Abstract
TMC-anti and TMC-syn, the two topological isomers of [FeIV(O)(TMC)(CH3CN)]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, or Me4cyclam), differ in the orientations of their FeIV=O units relative to the four methyl groups of the TMC ligand framework. The FeIV=O unit of TMC-anti points away from the four methyl groups, while that of TMC-syn is surrounded by the methyl groups, resulting in differences in their oxidative reactivities. TMC-syn reacts with HAT (hydrogen atom transfer) substrates at 1.3- to 3-fold faster rates than TMC-anti, but the reactivity difference increases dramatically in oxygen-atom transfer reactions. R2S substrates are oxidized into R2S=O products at rates 2-to-3 orders of magnitude faster by TMC-syn than TMC-anti. Even more remarkably, TMC-syn epoxidizes all the olefin substrates in this study, while TMC-anti reacts only with cis-cyclooctene but at a 100-fold slower rate. Comprehensive quantum chemical calculations have uncovered the key factors governing such reactivity differences found between these two topological isomers.
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Affiliation(s)
- Bittu Chandra
- Department of Chemistry, University of Minnesota, Minneapolis, MN55455
| | - Faiza Ahsan
- Institut de Química Computacional i Catàlisi and Department of Chemistry, University of Girona, 17003Girona, Spain
| | - Yuan Sheng
- Department of Chemistry, University of Minnesota, Minneapolis, MN55455
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi and Department of Chemistry, University of Girona, 17003Girona, Spain
- ICREA, 08010Barcelona, Spain
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, MN55455
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20
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Kallifidas D, Dhakal D, Chen M, Chen QY, Kokkaliari S, Colon Rosa NA, Ratnayake R, Bruner SD, Paul VJ, Ding Y, Luesch H. Biosynthesis of Dolastatin 10 in Marine Cyanobacteria, a Prototype for Multiple Approved Cancer Drugs. Org Lett 2024; 26:1321-1325. [PMID: 38330916 PMCID: PMC10915760 DOI: 10.1021/acs.orglett.3c04083] [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] [Indexed: 02/10/2024]
Abstract
Dolastatin 10, a potent tubulin-targeting marine anticancer natural product, provided the basis for the development of six FDA-approved antibody-drug conjugates. Through the screening of cyanobacterial Caldora penicillata environmental DNA libraries and metagenome sequencing, we identified its biosynthetic gene cluster. Functional prediction of 10 enzymes encoded in the 39 kb cluster supports the dolastatin 10 biosynthesis. The nonheme diiron monooxygenase DolJ was biochemically characterized to mediate the terminal thiazole formation in dolastatin 10.
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Affiliation(s)
- Dimitris Kallifidas
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Dipesh Dhakal
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Manyun Chen
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Qi-Yin Chen
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Sofia Kokkaliari
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Nicole A. Colon Rosa
- Department of Chemistry, University of Florida, Gainesville, FL 32611, United States
| | - Ranjala Ratnayake
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Steven D. Bruner
- Department of Chemistry, University of Florida, Gainesville, FL 32611, United States
| | - Valerie J. Paul
- Smithsonian Marine Station, Fort Pierce, FL 34949, United States
| | - Yousong Ding
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
| | - Hendrik Luesch
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), University of Florida, Gainesville, FL 32610, United States
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21
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Lee JL, Biswas S, Ziller JW, Bominaar EL, Hendrich MP, Borovik AS. Accessing a synthetic Fe IIIMn IV core to model biological heterobimetallic active sites. Chem Sci 2024; 15:2817-2826. [PMID: 38404374 PMCID: PMC10882444 DOI: 10.1039/d3sc04900k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/22/2023] [Indexed: 02/27/2024] Open
Abstract
Metalloproteins with dinuclear cores are known to bind and activate dioxygen, with a subclass of these proteins having active sites containing FeMn cofactors and activities ranging from long-range proton-coupled electron transfer (PCET) to post-translational peptide modification. While mechanistic studies propose that these metallocofactors access FeIIIMnIV intermediates, there is a dearth of related synthetic analogs. Herein, the first well-characterized synthetic FeIII-(μ-O)-MnIV complex is reported; this complex shows similar spectroscopic features as the catalytically competent FeIIIMnIV intermediate X found in Class Ic ribonucleotide reductase and demonstrates PCET function towards phenolic substrates. This complex is prepared from the oxidation of the isolable FeIII-(μ-O)-MnIII species, whose stepwise assembly is facilitated by a tripodal ligand containing phosphinic amido groups. Structural and spectroscopic studies found proton movement involving the FeIIIMnIII core, whereby the initial bridging hydroxido ligand is converted to an oxido ligand with concomitant protonation of one phosphinic amido group. This series of FeMn complexes allowed us to address factors that may dictate the preference of an active site for a heterobimetallic cofactor over one that is homobimetallic: comparisons of the redox properties of our FeMn complexes with those of the di-Fe analogs suggested that the relative thermodynamic ease of accessing an FeIIIMnIV core can play an important role in determining the metal ion composition when the key catalytic steps do not require an overly potent oxidant. Moreover, these complexes allowed us to demonstrate the effect of the hyperfine interaction from non-Fe nuclei on 57Fe Mössbauer spectra which is relevant to MnFe intermediates in proteins.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University Pittsburgh PA 15213 USA
| | - A S Borovik
- Department of Chemistry, University of California-Irvine Irvine CA 92697 USA
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22
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Jiao R, Zhao G, Zhang T. Structural Insights into the Reaction between Hydrogen Peroxide and Di-iron Complexes at the Ferroxidase Center of Ferritin. Inorg Chem 2024; 63:3359-3365. [PMID: 38315811 DOI: 10.1021/acs.inorgchem.3c03889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The Fe(II) oxidation mechanism in the ferroxidase center of heavy chain ferritin has been studied extensively. However, the actual production of H2O2 was found to be substantially lower than expected at low flux of Fe(II) to ferritin subunits. Here, we demonstrated that H2O2 could interact with the di-iron nuclear center, leading to the production of hydroxyl radicals and oxygen. Two reaction intermediates were captured in the ferroxidase center by using the time-lapse crystallographic techniques in a shellfish ferritin. The crystal structures revealed the binding of H2O2 as a μ -1,2-peroxo-diferric species and the binding of O2 to the diferric structure. This investigation sheds light on the reaction between the di-iron nuclear center and H2O2 and provides insights for the exploitation of metalloenzymes.
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Affiliation(s)
- Ruonan Jiao
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Guanghua Zhao
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Tuo Zhang
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
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23
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Yang B, Song X, Wang B. DFT mechanistic study of biomimetic diiron complex catalyzed dehydrogenation: Unexpected Fe(III)Fe(III)-1,1-μ-hydroperoxy active species for hydride abstraction. J Inorg Biochem 2024; 251:112426. [PMID: 37980877 DOI: 10.1016/j.jinorgbio.2023.112426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/03/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023]
Abstract
The diiron active site is pivotal in catalyzing transformations in both biological and chemical systems. Recently, a range of biomimetic diiron catalysts have been synthesized, drawing inspiration from the active architecture of soluble methane monooxygenase (sMMO). These catalysts have been successfully deployed for the dehydrogenation of indolines, marking a significant advancement in the field. Using density functional theory (DFT) calculations, we have identified a novel mechanistic pathway that governs the dehydrogenation of indolines catalyzed by a biomimetic diiron complex. Specifically, this reaction is facilitated by the transfer of a hybrid atom from the C1 position of the substrate to the distal oxygen atom of the Fe(III)Fe(III)-1,1-μ-hydroperoxy active species. This transfer serves as the rate-limiting step for the heterolytic cleavage of the OO bond, ultimately generating the substrate cation. The mechanism we propose aligns well with mechanistic investigations incorporating both kinetic isotope effect (KIE) measurements and evaluations of stereochemical selectivity. This research contributes to the broader scientific understanding of catalysis involving biomimetic diiron complexes and offers valuable insights into the catalytic behaviors of non-heme diiron metalloenzymes.
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Affiliation(s)
- Boxuan Yang
- Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xitong Song
- Fujian Provincial Key Laboratory of Ecology-Toxicological Effects & Control for Emerging Contaminants, College of Environmental and Biological Engineering, Putian University, Putian 351100, China; Key Laboratory of Ecological Environment and Information Atlas, Fujian Provincial University (Putian University), Putian 351100, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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24
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Murugan S, Iqbal T, Das D. Functional production and biochemical investigation of an integral membrane enzyme for olefin biosynthesis. Protein Sci 2024; 33:e4893. [PMID: 38160318 PMCID: PMC10804661 DOI: 10.1002/pro.4893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/24/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
Integral membrane enzymes play essential roles in a plethora of biochemical processes. The fatty acid desaturases (FADS)-like superfamily is an important group of integral membrane enzymes that catalyze a wide array of reactions, including hydroxylation, desaturation, and cyclization; however, due to the membrane-bound nature, the majority of these enzymes have remained poorly understood. UndB is a member of the FADS-like superfamily, which catalyzes fatty acid decarboxylation, a chemically challenging reaction at the membrane interface. UndB reaction produces terminal olefins that are prominent biofuel candidates and building blocks of polymers with widespread industrial applications. Despite the great importance of UndB for several biotechnological applications, the enzyme has eluded comprehensive investigation. Here, we report details of the expression, solubilization, and purification of several constructs of UndB to achieve the optimally functional enzyme. We gained important insights into the biochemical, biophysical, and catalytic properties of UndB, including the thermal stability and factors influencing the enzyme activity. Additionally, we established the ability and kinetics of UndB to produce dienes by performing di-decarboxylation of diacids. We found that the reaction proceeds by forming a mono-carboxylic acid intermediate. Our findings shed light on the unexplored biochemical properties of the UndB and extend opportunities for its rigorous mechanistic and structural characterization.
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Affiliation(s)
- Subhashini Murugan
- Department of Inorganic and Physical ChemistryIndian Institute of ScienceBangaloreIndia
| | - Tabish Iqbal
- Department of Inorganic and Physical ChemistryIndian Institute of ScienceBangaloreIndia
| | - Debasis Das
- Department of Inorganic and Physical ChemistryIndian Institute of ScienceBangaloreIndia
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25
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Kumar M, Gupta MK, Ansari M, Ansari A. C-H bond activation by high-valent iron/cobalt-oxo complexes: a quantum chemical modeling approach. Phys Chem Chem Phys 2024; 26:4349-4362. [PMID: 38235511 DOI: 10.1039/d3cp05866b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
High-valent metal-oxo species serve as key intermediates in the activation of inert C-H bonds. Here, we present a comprehensive DFT analysis of the parameters that have been proposed as influencing factors in modeled high-valent metal-oxo mediated C-H activation reactions. Our approach involves utilizing DFT calculations to explore the electronic structures of modeled FeIVO (species 1) and CoIVO ↔ CoIII-O˙ (species 2), scrutinizing their capacity to predict improved catalytic activity. DFT and DLPNO-CCSD(T) calculations predict that the iron-oxo species possesses a triplet as the ground state, while the cobalt-oxo has a doublet as the ground state. Furthermore, we have investigated the mechanistic pathways for the first C-H bond activation, as well as the desaturation of the alkanes. The mechanism was determined to be a two-step process, wherein the first hydrogen atom abstraction (HAA) represents the rate-limiting step, involving the proton-coupled electron transfer (PCET) process. However, we found that the second HAA step is highly exothermic for both species. Our calculations suggest that the iron-oxo species (Fe-O = 1.672 Å) exhibit relatively sluggish behavior compared to the cobalt-oxo species (Co-O = 1.854 Å) in C-H bond activation, attributed to a weak metal-oxygen bond. MO, NBO, and deformation energy analysis reveal the importance of weakening the M-O bond in the cobalt species, thereby reducing the overall barrier to the reaction. This catalyst was found to have a C-H activation barrier relatively smaller than that previously reported in the literature.
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Affiliation(s)
- Manjeet Kumar
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Manoj Kumar Gupta
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
| | - Mursaleem Ansari
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
| | - Azaj Ansari
- Department of Chemistry, Central University of Haryana, Mahendergarh-123031, Haryana, India.
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26
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Liu C, Powell MM, Rao G, Britt RD, Rittle J. Bioinformatic Discovery of a Cambialistic Monooxygenase. J Am Chem Soc 2024; 146:1783-1788. [PMID: 38198693 PMCID: PMC10811679 DOI: 10.1021/jacs.3c12131] [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: 10/30/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/12/2024]
Abstract
Dinuclear monooxygenases mediate challenging C-H bond oxidation reactions throughout nature. Many of these enzymes are presumed to exclusively utilize diiron cofactors. Herein we report the bioinformatic discovery of an orphan dinuclear monooxygenase that preferentially utilizes a heterobimetallic manganese-iron (Mn/Fe) cofactor to mediate an O2-dependent C-H bond hydroxylation reaction. Unlike the structurally similar Mn/Fe-dependent monooxygenase AibH2, the diiron form of this enzyme (SfbO) exhibits a nascent enzymatic activity. This behavior raises the possibility that many other dinuclear monooxygenases may be endowed with the capacity to harness cofactors with a variable metal content.
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Affiliation(s)
- Chang Liu
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Magan M. Powell
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jonathan Rittle
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
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27
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Jeong D, Kim K, Lee Y, Cho J. Synthetic Advances for Mechanistic Insights: Metal-Oxygen Intermediates with a Macrocyclic Pyridinophane System. Acc Chem Res 2024; 57:120-130. [PMID: 38110355 DOI: 10.1021/acs.accounts.3c00582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
ConspectusMetalloenzymes, which are proteins containing earth-abundant transition-metal ions as cofactors in the active site, generate various metal-oxygen intermediates via activating a dioxygen molecule (O2) to mediate vital metabolic functions, such as the oxidative metabolism of xenobiotics and the biotransformation of naturally occurring molecules. By replicating the active sites of metalloenzymes, many bioinorganic chemists have studied the geometric and electronic properties and reactivities of model complexes to understand the nature of enzymatic intermediates and develop bioinspired metal catalysts. Among the reported model complexes, nonporphyrinic macrocyclic ligands are the predominant coordination system widely used in stabilizing and isolating diverse metal-oxygen intermediates, which allows us to extensively investigate the physicochemical characteristics of the analogs of reactive intermediates of metalloenzymes. In particular, it has been reported that the ring size of the macrocyclic ligands, defined by the number of atoms in the macrocyclic ring, drastically affects the identity of the metal-oxygen intermediate. Thus, systematic modification of the macrocyclic ligands has been a great subject being examined in various inorganic fields.In this Account, we describe synthetic advances of a macrocyclic ligand system by introducing pyridine donors into a 12-membered tetraazamacrocyclic ligand (12-TMC) that initially has 4 amine donors. Interestingly, the backbone of the pyridinophane ligand with 2 pyridine and 2 amine donors in a 12-membered ring is shown to be much more folded than in other macrocyclic ligands, thereby allowing the axial and equatorial donors to separately control the electronic structure of metal complexes. Then, we looked over independent electronic and steric effects on metal-oxygen species with thorough physicochemical analysis. The NiIII-peroxo complexes exhibit nucleophilic reactivity dependent on the steric hindrance of the second coordination sphere. Furthermore, the C-H bond strength of the second coordination sphere has also been an important factor in determining the stability of MnIV-bis(hydroxo) intermediates. Electronic tuning on CoIII-hydroperoxo intermediates results in a trend between the electron-donating abilities of para-substituents on pyridine in the pyridinophane ligand and electrophilic reactivities, from which mechanistic insights into the metal-hydroperoxo species have been gained. Importantly, the metal-oxygen intermediates supported by the pyridinophane ligand system have revealed quite challenging chemical reactions, including dioxygenase-like nitrile activation by CoIII-peroxo intermediates and the oxidation of aldehyde and aromatic compounds by manganese-oxygen intermediates. Based on the fine substitution of donors, we have addressed that those novel reactions originated from the unique framework of the pyridinophane system incorporating spin-crossover behavior and high redox potentials of the metal-oxygen intermediates. These results will be valuable for the structure-activity relationship of metal-oxygen intermediates, giving a better understanding on the enzymatic coordination system where amino acid ligands vary for specific chemical reactions.
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Affiliation(s)
- Donghyun Jeong
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kyungmin Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yujeong Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaeheung Cho
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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28
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Zheng Z, Xiong J, Bu J, Ren D, Lee YH, Yeh YC, Lin CI, Parry R, Guo Y, Liu HW. Reconstitution of the Final Steps in the Biosynthesis of Valanimycin Reveals the Origin of Its Characteristic Azoxy Moiety. Angew Chem Int Ed Engl 2024; 63:e202315844. [PMID: 37963815 PMCID: PMC10843709 DOI: 10.1002/anie.202315844] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/11/2023] [Accepted: 11/14/2023] [Indexed: 11/16/2023]
Abstract
Valanimycin is an azoxy-containing natural product isolated from the fermentation broth of Streptomyces viridifaciens MG456-hF10. While the biosynthesis of valanimycin has been partially characterized, how the azoxy group is constructed remains obscure. Herein, the membrane protein VlmO and the putative hydrazine synthetase ForJ from the formycin biosynthetic pathway are demonstrated to catalyze N-N bond formation converting O-(l-seryl)-isobutyl hydroxylamine into N-(isobutylamino)-l-serine. Subsequent installation of the azoxy group is shown to be catalyzed by the non-heme diiron enzyme VlmB in a reaction in which the N-N single bond in the VlmO/ForJ product is oxidized by four electrons to yield the azoxy group. The catalytic cycle of VlmB appears to begin with a resting μ-oxo diferric complex in VlmB, as supported by Mössbauer spectroscopy. This study also identifies N-(isobutylamino)-d-serine as an alternative substrate for VlmB leading to two azoxy regioisomers. The reactions catalyzed by the kinase VlmJ and the lyase VlmK during the final steps of valanimycin biosynthesis are established as well. The biosynthesis of valanimycin was thus fully reconstituted in vitro using the enzymes VlmO/ForJ, VlmB, VlmJ and VlmK. Importantly, the VlmB-catalyzed reaction represents the first example of enzyme-catalyzed azoxy formation and is expected to proceed by an atypical mechanism.
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Affiliation(s)
- Ziyang Zheng
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
| | - Jin Xiong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA-15213, USA
| | - Junling Bu
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX-78712, USA
| | - Daan Ren
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
| | - Yu-Hsuan Lee
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
| | - Yu-Cheng Yeh
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
| | - Chia-I Lin
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
| | - Ronald Parry
- Department of Chemistry, Rice University, Houston, TX-77005, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA-15213, USA
| | - Hung-Wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, TX-78712, USA
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX-78712, USA
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29
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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.
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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.)
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30
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Li Y, Abelson C, Que L, Wang D. 10 6-fold faster C-H bond hydroxylation by a Co III,IV2(µ-O) 2 complex [via a Co III2(µ-O)(µ-OH) intermediate] versus its Fe IIIFe IV analog. Proc Natl Acad Sci U S A 2023; 120:e2307950120. [PMID: 38085777 PMCID: PMC10743362 DOI: 10.1073/pnas.2307950120] [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: 05/11/2023] [Accepted: 11/04/2023] [Indexed: 12/24/2023] Open
Abstract
The hydroxylation of C-H bonds can be carried out by the high-valent CoIII,IV2(µ-O)2 complex 2a supported by the tetradentate tris(2-pyridylmethyl)amine ligand via a CoIII2(µ-O)(µ-OH) intermediate (3a). Complex 3a can be independently generated either by H-atom transfer (HAT) in the reaction of 2a with phenols as the H-atom donor or protonation of its conjugate base, the CoIII2(µ-O)2 complex 1a. Resonance Raman spectra of these three complexes reveal oxygen-isotope-sensitive vibrations at 560 to 590 cm-1 associated with the symmetric Co-O-Co stretching mode of the Co2O2 diamond core. Together with a Co•••Co distance of 2.78(2) Å previously identified for 1a and 2a by Extended X-ray Absorption Fine Structure (EXAFS) analysis, these results provide solid evidence for their "diamond core" structural assignments. The independent generation of 3a allows us to investigate HAT reactions of 2a with phenols in detail, measure the redox potential and pKa of the system, and calculate the O-H bond strength (DO-H) of 3a to shed light on the C-H bond activation reactivity of 2a. Complex 3a is found to be able to transfer its hydroxyl ligand onto the trityl radical to form the hydroxylated product, representing a direct experimental observation of such a reaction by a dinuclear cobalt complex. Surprisingly, reactivity comparisons reveal 2a to be 106-fold more reactive in oxidizing hydrocarbon C-H bonds than corresponding FeIII,IV2(µ-O)2 and MnIII,IV2(µ-O)2 analogs, an unexpected outcome that raises the prospects for using CoIII,IV2(µ-O)2 species to oxidize alkane C-H bonds.
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Affiliation(s)
- Yan Li
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT59812
| | - Chase Abelson
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN55455
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN55455
| | - Dong Wang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT59812
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31
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Shi J, Zang X, Zhao Z, Shen Z, Li W, Zhao G, Zhou J, Du YL. Conserved Enzymatic Cascade for Bacterial Azoxy Biosynthesis. J Am Chem Soc 2023; 145:27131-27139. [PMID: 38018127 DOI: 10.1021/jacs.3c12018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Azoxy compounds exhibit a wide array of biological activities and possess distinctive chemical properties. Although there has been considerable interest in the biosynthetic mechanisms of azoxy metabolites, the enzymatic basis responsible for azoxy bond formation has remained largely enigmatic. In this study, we unveil the enzyme cascade that constructs the azoxy bond in valanimycin biosynthesis. Our research demonstrates that a pair of metalloenzymes, comprising a membrane-bound hydrazine synthase and a nonheme diiron azoxy synthase, collaborate to convert an unstable pathway intermediate to an azoxy product through a hydrazine-azo-azoxy pathway. Additionally, by characterizing homologues of this enzyme pair from other azoxy metabolite pathways, we propose that this two-enzyme cascade could represent a conserved enzymatic strategy for azoxy bond formation in bacteria. These findings provide significant mechanistic insights into biological N-N bond formation and should facilitate the targeted isolation of bioactive azoxy compounds through genome mining.
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Affiliation(s)
- Jingkun Shi
- Department of Microbiology, and Department of Pharmacy of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xin Zang
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Zhijie Zhao
- Department of Microbiology, and Department of Pharmacy of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhuanglin Shen
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Wei Li
- Department of Microbiology, and Department of Pharmacy of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Guiyun Zhao
- Department of Microbiology, and Department of Pharmacy of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiahai Zhou
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yi-Ling Du
- Department of Microbiology, and Department of Pharmacy of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
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32
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Finke S, Stammler A, Oldengott J, Walleck S, Glaser T. Direct and remote control of electronic structures and redox potentials in μ-oxo diferric complexes. Dalton Trans 2023; 52:17548-17561. [PMID: 37962521 DOI: 10.1039/d3dt02734a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Non-heme diiron enzymes activate O2 for the oxidation of substrates in the form of peroxo FeIII2 or high-valent FeIV2 intermediates. We have developed a dinucleating bis(tetradentate) ligand system that stabilizes peroxo and hydroperoxo FeIII2 complexes with terminal 6-methylpyridine donors, while the peroxo FeIII2 intermediate is reactive with terminal pyridine donors presumably via conversion to a fluent high-valent FeIV2 intermediate. We present here a derivative with electron-donating methoxy substituents at the pyridine donors and its diferric complexes with an {FeIIIX(μ-O)FeIIIX} (X- = Cl-, OAc-, and OH-) or an {FeIII(μ-O)(μ-OAc)FeIII} core. The complex-induced oxidation of EtOH with H2O2 provides μ-OAc-, and in acetone, the complex with mixed OH-/OAc- exogenous donors is obtained. Both reactivities indicate a reactive fluent peroxo FeIII2 intermediate. The coupling constant J and the LMCT transitions are insensitive to the nature of the directly bound ligands X- and reflect mainly the electronic structure of the central {FeIII(μ-O)FeIII} core, while Mössbauer spectroscopy and d-d transitions probe the local FeIII sites. The remote methoxy substituents decrease the potential for the oxidation to FeIV by ∼100 mV, while directly bound OH- in {FeIII(OH)(μ-O)FeIII(OH)} with a short 1.91 Å FeIII-OOH bond decreases the potential by 590 mV compared to {FeIII(OAc)(μ-O)FeIII(OAc)} with a 2.01 Å FeIII-OOAc bond. Interestingly, this FeIII-OH bond is even shorter (1.87 Å) in the mixed OH-/OAc- complex but the potential is the mean value of the potentials of the OH-/OH- and OAc-/OAc- complexes, thus reflecting the electron density of the central {FeIII(μ-O)FeIII} core and not of the local FeIII-OH unit.
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Affiliation(s)
- Sebastian Finke
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
| | - Anja Stammler
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
| | - Jan Oldengott
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
| | - Stephan Walleck
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
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Guo YY, Tian ZH, Ma C, Han YC, Bai D, Jiang Z. Unlocking mild-condition benzene ring contraction using nonheme diiron N-oxygenase. Chem Sci 2023; 14:11907-11913. [PMID: 37920353 PMCID: PMC10619644 DOI: 10.1039/d3sc04660e] [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: 09/04/2023] [Accepted: 10/09/2023] [Indexed: 11/04/2023] Open
Abstract
Benzene ring contractions are useful yet rare reactions that offer a convenient synthetic route to various valuable chemicals. However, the traditional methods of benzene contraction rely on noble-metal catalysts under extreme conditions with poor efficiency and uncontrollable selectivity. Mild-condition contractions of the benzene ring are rarely reported. This study presents a one-step, one-pot benzene ring contraction reaction mediated by an engineered nonheme diiron N-oxygenase. Using various aniline substrates as amine sources, the enzyme causes the phloroglucinol-benzene-ring contraction to afford a series of 4-cyclopentene-1,3-dione structures. A reaction detail study reveals that the nonheme diiron N-oxygenase first oxidizes the aromatic amine to a nitroso intermediate, which then attacks the phloroglucinol anion and causes benzene ring contraction. Besides, we have identified two potent antitumor compounds from the ring-contracted products.
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Affiliation(s)
- Yuan-Yang Guo
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
| | - Ze-Hua Tian
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
| | - ChunHua Ma
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
| | - Yu-Chen Han
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
| | - DaChang Bai
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
| | - ZhiYong Jiang
- State Key Laboratory of Antiviral Drugs, Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang Henan 453007 China
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34
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Zhao C, Wang T, Liu X, Zhu Z, Ying X, Li XL, Tang J. Peroxido-bridged chiral double-decker dysprosium macrocycles. Dalton Trans 2023; 52:15456-15461. [PMID: 37466249 DOI: 10.1039/d3dt01540h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Lanthanide peroxides show high reactivity in oxidative coupling of methane (OCM). However, the number of isolated and structurally characterized molecular species remains relatively small. To the best of our knowledge, homochiral molecule-based lanthanide peroxides have not been reported. Herein, two pairs of side-on peroxido-bridged dinuclear hexaazamacrocyclic dysprosium enantiomers with formulas [Dy2(LES/R)2L2O2](BPh4)2·CH3OH·CH3CN (where LE is derived from the condensation reaction between (1S,2S)/(1R,2R)-1,2-diphenylethylenediamine and 2,6-diformylpyridine; HL = 2,6-diphenylphenol) (1/2) and [Dy2(LES/R)2Cl2O2](BPh4)2·2CH3CN (3/4) are specially designed and created with the help of hydrogen peroxide. The out-of-phase alternating-current magnetic susceptibility of 1/2 gives rise to frequency-dependent peaks between 6 and 32 K under a zero applied direct current (dc) field, while no peak at any temperature and frequency was observed for 3/4 implying the presence of a weak axial crystal field (CF).
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Affiliation(s)
- Chen Zhao
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Tingting Wang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Xiaodong Liu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Zhenhua Zhu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xu Ying
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Xiao-Lei Li
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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35
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Depenbrock F, Limpke T, Bill E, SantaLucia DJ, van Gastel M, Walleck S, Oldengott J, Stammler A, Bögge H, Glaser T. Reactivities and Electronic Structures of μ-1,2-Peroxo and μ-1,2-Superoxo Co IIICo III Complexes: Electrophilic Reactivity and O 2 Release Induced by Oxidation. Inorg Chem 2023; 62:17913-17930. [PMID: 37838986 DOI: 10.1021/acs.inorgchem.3c02782] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Peroxo complexes are key intermediates in water oxidation catalysis (WOC). Cobalt plays an important role in WOC, either as oxides CoOx or as {CoIII(μ-1,2-peroxo)CoIII} complexes, which are the oldest peroxo complexes known. The oxidation of {CoIII(μ-1,2-peroxo)CoIII} complexes had usually been described to form {CoIII(μ-1,2-superoxo)CoIII} complexes; however, recently the formation of {CoIV(μ-1,2-peroxo)CoIII} species were suggested. Using a bis(tetradentate) dinucleating ligand, we present here the synthesis and characterization of {CoIII(μ-1,2-peroxo)(μ-OH)CoIII} and {CoIII(μ-OH)2CoIII} complexes. Oxidation of {CoIII(μ-1,2-peroxo)(μ-OH)CoIII} at -40 °C in CH3CN provides the stable {CoIII(μ-1,2-superoxo)(μ-OH)CoIII} species and activates electrophilic reactivity. Moreover, {CoIII(μ-1,2-peroxo)(μ-OH)CoIII} catalyzes water oxidation, not molecularly but rather via CoOx films. While {CoIII(μ-1,2-peroxo)(μ-OH)CoIII} can be reversibly deprotonated with DBU at -40 °C in CH3CN, {CoIII(μ-1,2-superoxo)(μ-OH)CoIII} undergoes irreversible conversions upon reaction with bases to a new intermediate that is also the decay product of {CoIII(μ-1,2-superoxo)(μ-OH)CoIII} in aqueous solution at pH > 2. Based on a combination of experimental methods, the new intermediate is proposed to have a {CoII(μ-OH)CoIII} core formed by the release of O2 from {CoIII(μ-1,2-superoxo)(μ-OH)CoIII} confirmed by a 100% yield of O2 upon photocatalytic oxidation of {CoIII(μ-1,2-peroxo)(μ-OH)CoIII}. This release of O2 by oxidation of a peroxo intermediate corresponds to the last step in molecular WOC.
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Affiliation(s)
- Felix Depenbrock
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Thomas Limpke
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstr. 34-36, Mülheim an der Ruhr D-45470, Germany
| | - Daniel J SantaLucia
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany
| | - Maurice van Gastel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr D-45470, Germany
| | - Stephan Walleck
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Jan Oldengott
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Anja Stammler
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Hartmut Bögge
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, Bielefeld D-33615, Germany
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36
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Xie Y, Ramirez D, Chen G, He G, Sun Y, Murdoch FK, Löffler FE. Genome-Wide Expression Analysis Unravels Fluoroalkane Metabolism in Pseudomonas sp. Strain 273. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15925-15935. [PMID: 37647029 PMCID: PMC11217894 DOI: 10.1021/acs.est.3c03855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Pseudomonas sp. strain 273 grows with medium-chain terminally fluorinated alkanes under oxic conditions, releases fluoride, and synthesizes long-chain fluorofatty acids. To shed light on the genes involved in fluoroalkane metabolism, genome, and transcriptome sequencing of strain 273 grown with 1,10-difluorodecane (DFD), decane, and acetate were performed. Strain 273 harbors three genes encoding putative alkane monooxygenases (AlkB), key enzymes for initiating alkane degradation. Transcripts of alkB-2 were significantly more abundant in both decane- and DFD-grown cells compared to acetate-grown cells, suggesting AlkB-2 catalyzes the attack on terminal CH3 and CH2F groups. Coordinately expressed with alkB-2 was an adjacent gene encoding a fused ferredoxin-ferredoxin reductase (Fd-Fdr). Phylogenetic analysis distinguished AlkB that couples with fused Fd-Fdr reductases from AlkB with alternate architectures. A gene cluster containing an (S)-2-haloacid dehalogenase (had) gene was up-regulated in cells grown with DFD, suggesting a possible role in the removal of the ω-fluorine. Genes involved in long-chain fatty acid biosynthesis were not differentially expressed during growth with acetate, decane, or DFD, suggesting the bacterium's biosynthetic machinery does not discriminate against monofluoro-fatty acid intermediates. The analysis sheds first light on genes and catalysts involved in the microbial metabolism of fluoroalkanes.
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Affiliation(s)
- Yongchao Xie
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Diana Ramirez
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gao Chen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Guang He
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Yanchen Sun
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Fadime Kara Murdoch
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Frank E Löffler
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, United States
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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37
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Jiang YY, Chen C. Recent advances in computational studies on Cu-catalyzed aerobic reactions: cooperation of copper catalysts and dioxygen. Org Biomol Chem 2023; 21:7852-7872. [PMID: 37725071 DOI: 10.1039/d3ob00976a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
O2, one of the ideal oxidants, suffers from low solubility, low oxidizability, low selectivity and a triplet ground state when applied in organic synthesis. Biomimetic copper catalysis has been demonstrated to be a powerful method for activating and transforming O2 to conduct aerobic reactions for a long time. On the other hand, the structures of Cu-O2 complexes are complex with diverse downstream reactions, whereas active copper intermediates were rarely identified by experimental methods, making the mechanisms of many Cu-catalyzed aerobic reactions far from clear. In this context, computational studies emerged as an effective alternative to mechanistic studies on Cu-catalyzed aerobic reactions. This review introduces the relevant computational studies since 2012, focusing on showing the cooperation of copper catalysts and O2 in dehydrogenation, oxygenation and coupling reactions.
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Affiliation(s)
- Yuan-Ye Jiang
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, People's Republic of China.
| | - Chao Chen
- Key Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, People's Republic of China.
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38
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Carter S, Tao W, Majumder R, Sokolov AY, Zhang S. Two-State Hydrogen Atom Transfer Reactivity of Unsymmetric [Cu 2(O)(NO)] 2+ Complexes. J Am Chem Soc 2023; 145:17779-17785. [PMID: 37540110 DOI: 10.1021/jacs.3c04510] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
We report the temperature-dependent spin switching of dicopper oxo nitrosyl [Cu2(O)(NO)]2+ complexes and their influence on hydrogen atom transfer (HAT) reactivity. Electron paramagnetic resonance (EPR) and Evans method analysis suggest that [Cu2(O)(NO)]2+ complexes transition from the S = 1/2 to the S = 3/2 state around ca. 202 K. At low temperatures (198 K) where S = 3/2 dominates, a strong correlation between the rate of HAT (kHAT) and the population of the S = 1/2 state was identified (R2 = 0.988), suggesting that the HAT by [Cu2(O)(NO)]2+ complexes proceeds by the S = 1/2 isomer. Installation of functional groups that introduce an unsymmetric secondary coordination environment accelerates the HAT rates through perturbation of the spin equilibria. Given the often unsymmetric coordination sphere of bimetallic active sites in natural proteins, we anticipate that similar strategies could be employed by metalloenzymes to control HAT reactions.
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Affiliation(s)
- Samantha Carter
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Wenjie Tao
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Rajat Majumder
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Alexander Yu Sokolov
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Shiyu Zhang
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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39
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Ajaykamal T, Palaniandavar M. Mononuclear nickel(ii)-flavonolate complexes of tetradentate tripodal 4N ligands as structural and functional models for quercetin 2,4-dioxygenase: structures, spectra, redox and dioxygenase activity. RSC Adv 2023; 13:24674-24690. [PMID: 37601601 PMCID: PMC10436029 DOI: 10.1039/d3ra04834a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 08/01/2023] [Indexed: 08/22/2023] Open
Abstract
Three new nickel(ii)-flavonolate complexes of the type [Ni(L)(fla)](ClO4) 1-3, where L is the tripodal 4N ligand tris(pyrid-2-ylmethyl)amine (tpa, L1) or (pyrid-2-ylmethyl)bis(6-methylpyrid-2-ylmethyl)amine (6-Me2-tpa, L2) or tris(N-Et-benzimidazol-2-ylmethyl)amine (Et-ntb, L3), have been isolated as functional models for Ni(ii)-containing quercetin 2,4-dioxygenase. Single crystal X-ray structures of 1 and 3 reveal that Ni(ii) is involved in π-back bonding with flavonolate (fla-), as evident from enhancement in C[double bond, length as m-dash]O bond length upon coordination [H(fla), 1.232(3); 1, 1.245(7); 3, 1.262(8) Å]. More asymmetric chelation of fla- in 3 than in 1 [Δd = (Ni-Ocarbonyl - Ni-Oenolate): 1, 0.126; 3, 0.182 Å] corresponds to lower π-delocalization in 3 with electron-releasing N-Et substituent. The optimized structures of 1-3 and their geometrical isomers have been computed by DFT methods. The HOMO and LUMO, both localized on Ni(ii)-bound fla-, are highly conjugated bonding π- and antibonding π*-orbitals respectively. They are located higher in energy than the Ni(ii)-based MOs (HOMO-1, dx2-y2; HOMO-2/6, dz2), revealing that the Ni(ii)-bound fla- rather than Ni(ii) would undergo oxidation upon exposure to dioxygen. The results of computational studies, in combination with spectral and electrochemical studies, support the involvement of redox-inactive Ni(ii) in π-back bonding with fla-, tuning the π-delocalization in fla- and hence its activation. Upon exposure to dioxygen, all the flavonolate adducts in DMF solution decompose to produce CO and depside, which then is hydrolyzed to give the corresponding acids at 70 °C. The highest rate of dioxygenase reactivity of 3 (kO2: 3 (29.10 ± 0.16) > 1 (16.67 ± 0.70) > 2 (1.81 ± 0.04 × 10-1 M-1 s-1)), determined by monitoring the disappearance of the LMCT band in the range 440-450 nm, is ascribed to the electron-releasing N-Et substituent on bzim ring, which decreases the π-delocalization in fla- and enhances its activation.
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Affiliation(s)
- Tamilarasan Ajaykamal
- Department of Chemistry, Bharathidasan University Tiruchirapalli 620 024 Tamil Nadu India +91-431-2407043 +91-431-2407125
| | - Mallayan Palaniandavar
- Department of Chemistry, Bharathidasan University Tiruchirapalli 620 024 Tamil Nadu India +91-431-2407043 +91-431-2407125
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40
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Guo YY, Tian ZH, Han YC, Ma D, Shao T, Jiang Z. Hantzsch Ester as Efficient and Economical NAD(P)H Mimic for In Vitro Bioredox Reactions. Chemistry 2023; 29:e202301180. [PMID: 37263982 DOI: 10.1002/chem.202301180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/21/2023] [Accepted: 06/01/2023] [Indexed: 06/03/2023]
Abstract
Biocatalysis has emerged as a valuable and reliable tool for industrial and academic societies, particularly in fields related to bioredox reactions. The cost of cofactors, especially those needed to be replenished at stoichiometric amounts or more, is the chief economic concern for bioredox reactions. In this study, a readily accessible, inexpensive, and bench-stable Hantzsch ester is verified as the viable and efficient NAD(P)H mimic by four enzymatic redox transformations, including two non-heme diiron N-oxygenases and two flavin-dependent reductases. This finding provides the potential to significantly reduce the costs of NAD(P)H-relying bioredox reactions.
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Affiliation(s)
- Yuan-Yang Guo
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Ze-Hua Tian
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Yu-Chen Han
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Dandan Ma
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Tianju Shao
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
| | - Zhiyong Jiang
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education NMPA Key Laboratory for Research and Evaluation of Innovative Drug Henan Key Laboratory of Organic Functional Molecule and Drug Innovation School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
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41
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Powell M, Rao G, Britt RD, Rittle J. Enzymatic Hydroxylation of Aliphatic C-H Bonds by a Mn/Fe Cofactor. J Am Chem Soc 2023; 145:16526-16537. [PMID: 37471626 PMCID: PMC10401708 DOI: 10.1021/jacs.3c03419] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Indexed: 07/22/2023]
Abstract
The aerobic oxidation of carbon-hydrogen (C-H) bonds in biology is currently known to be accomplished by a limited set of cofactors that typically include heme, nonheme iron, and copper. While manganese cofactors perform difficult oxidation reactions, including water oxidation within Photosystem II, they are generally not known to be used for C-H bond activation, and those that do catalyze this important reaction display limited intrinsic reactivity. Here we report that the 2-aminoisobutyric acid hydroxylase from Rhodococcus wratislaviensis, AibH1H2, requires manganese to functionalize a strong, aliphatic C-H bond (BDE = 100 kcal/mol). Structural and spectroscopic studies of this enzyme reveal a redox-active, heterobimetallic manganese-iron active site at the locus of O2 activation and substrate coordination. This result expands the known reactivity of biological manganese-iron cofactors, which was previously restricted to single-electron transfer or stoichiometric protein oxidation. Furthermore, the AibH1H2 cofactor is supported by a protein fold distinct from typical bimetallic oxygenases, and bioinformatic analyses identify related proteins abundant in microorganisms. This suggests that many uncharacterized monooxygenases may similarly require manganese to perform oxidative biochemical tasks.
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Affiliation(s)
- Magan
M. Powell
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jonathan Rittle
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
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42
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Li L, Shen S, Bickler P, Jacobson MP, Wu LF, Altschuler SJ. Searching for molecular hypoxia sensors among oxygen-dependent enzymes. eLife 2023; 12:e87705. [PMID: 37494095 PMCID: PMC10371230 DOI: 10.7554/elife.87705] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/09/2023] [Indexed: 07/27/2023] Open
Abstract
The ability to sense and respond to changes in cellular oxygen levels is critical for aerobic organisms and requires a molecular oxygen sensor. The prototypical sensor is the oxygen-dependent enzyme PHD: hypoxia inhibits its ability to hydroxylate the transcription factor HIF, causing HIF to accumulate and trigger the classic HIF-dependent hypoxia response. A small handful of other oxygen sensors are known, all of which are oxygen-dependent enzymes. However, hundreds of oxygen-dependent enzymes exist among aerobic organisms, raising the possibility that additional sensors remain to be discovered. This review summarizes known and potential hypoxia sensors among human O2-dependent enzymes and highlights their possible roles in hypoxia-related adaptation and diseases.
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Affiliation(s)
- Li Li
- Department of Pharmaceutical Chemistry, University of California San Francisco, San FranciscoSan FranciscoUnited States
| | - Susan Shen
- Department of Pharmaceutical Chemistry, University of California San Francisco, San FranciscoSan FranciscoUnited States
- Department of Psychiatry, University of California, San FranciscoSan FranciscoUnited States
| | - Philip Bickler
- Hypoxia Research Laboratory, University of California San Francisco, San FranciscoSan FranciscoUnited States
- Center for Health Equity in Surgery and Anesthesia, University of California San Francisco, San FranciscoSan FranciscoUnited States
- Anesthesia and Perioperative Care, University of California San Francisco, San FranciscoSan FranciscoUnited States
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, University of California San Francisco, San FranciscoSan FranciscoUnited States
| | - Lani F Wu
- Department of Pharmaceutical Chemistry, University of California San Francisco, San FranciscoSan FranciscoUnited States
| | - Steven J Altschuler
- Department of Pharmaceutical Chemistry, University of California San Francisco, San FranciscoSan FranciscoUnited States
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43
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He X, Iliescu A, Yang T, Arguilla MQ, Chen T, Kulik HJ, Dincă M. Reversible O-O Bond Scission and O 2 Evolution at MOF-Supported Tetramanganese Clusters. J Am Chem Soc 2023. [PMID: 37471064 DOI: 10.1021/jacs.3c05374] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
The scission of the O-O bond in O2 during respiration and the formation of the O-O bond during photosynthesis are the engines of aerobic life. Likewise, the reduction of O2 and the oxidation of reduced oxygen species to form O2 are indispensable components for emerging renewable technologies, including energy storage and conversion, yet discrete molecule-like systems that promote these fundamental reactions are rare. Herein, we report a square-planar tetramanganese cluster formed by self-assembly within a metal-organic framework that reversibly reduces O2 by four electrons, facilitating the interconversion between molecular O2 and metal-oxo species. The tetranuclear cluster spontaneously cleaves the O-O bond of O2 at room temperature to generate a tetramanganese-bis(μ2-oxo) species, which, in turn, is competent for O-O bond reformation and O2 evolution at elevated temperatures, enabled by the head-to-head orientation of two oxo species. This study demonstrates the viability of four-electron interconversion between molecular O2 and metal-oxo species and highlights the importance of site isolation for achieving multi-electron chemistry at polynuclear metal clusters.
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Affiliation(s)
- Xin He
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Andrei Iliescu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Tzuhsiung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Maxx Q Arguilla
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Tianyang Chen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Mircea Dincă
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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44
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Zars E, Gravogl L, Gau MR, Carroll PJ, Meyer K, Mindiola DJ. Isostructural bridging diferrous chalcogenide cores [Fe II(μ-E)Fe II] (E = O, S, Se, Te) with decreasing antiferromagnetic coupling down the chalcogenide series. Chem Sci 2023; 14:6770-6779. [PMID: 37350823 PMCID: PMC10283490 DOI: 10.1039/d3sc01094e] [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: 02/27/2023] [Accepted: 05/24/2023] [Indexed: 06/24/2023] Open
Abstract
Iron compounds containing a bridging oxo or sulfido moiety are ubiquitous in biological systems, but substitution with the heavier chalcogenides selenium and tellurium, however, is much rarer, with only a few examples reported to date. Here we show that treatment of the ferrous starting material [(tBupyrpyrr2)Fe(OEt2)] (1-OEt2) (tBupyrpyrr2 = 3,5-tBu2-bis(pyrrolyl)pyridine) with phosphine chalcogenide reagents E = PR3 results in the neutral phosphine chalcogenide adduct series [(tBupyrpyrr2)Fe(EPR3)] (E = O, S, Se; R = Ph; E = Te; R = tBu) (1-E) without any electron transfer, whereas treatment of the anionic starting material [K]2[(tBupyrpyrr2)Fe2(μ-N2)] (2-N2) with the appropriate chalcogenide transfer source yields cleanly the isostructural ferrous bridging mono-chalcogenide ate complexes [K]2[(tBupyrpyrr2)Fe2(μ-E)] (2-E) (E = O, S, Se, and Te) having significant deviation in the Fe-E-Fe bridge from linear in the case of E = O to more acute for the heaviest chalcogenide. All bridging chalcogenide complexes were analyzed using a variety of spectroscopic techniques, including 1H NMR, UV-Vis electronic absorbtion, and 57Fe Mössbauer. The spin-state and degree of communication between the two ferrous ions were probed via SQUID magnetometry, where it was found that all iron centers were high-spin (S = 2) FeII, with magnetic exchange coupling between the FeII ions. Magnetic studies established that antiferromagnetic coupling between the ferrous ions decreases as the identity of the chalcogen is tuned from O to the heaviest congener Te.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Lisa Gravogl
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Michael R Gau
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Karsten Meyer
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
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45
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Shen J, Wu G, Pierce BS, Tsai AL, Zhou M. Free ferrous ions sustain activity of mammalian stearoyl-CoA desaturase-1. J Biol Chem 2023:104897. [PMID: 37290533 PMCID: PMC10359943 DOI: 10.1016/j.jbc.2023.104897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/26/2023] [Accepted: 06/05/2023] [Indexed: 06/10/2023] Open
Abstract
Mammalian stearoyl-CoA desaturase-1 (SCD1) introduces a double-bond to a saturated long-chain fatty acid in a reaction catalyzed by a diiron center. The diiron center is well-coordinated by conserved histidine residues and is thought to remain with the enzyme. However, we find here that SCD1 progressively loses its activity during catalysis and becomes fully inactive after nine turnovers. Further studies show that the inactivation of SCD1 is due to the loss of an iron (Fe) ion in the diiron center, and that the addition of free ferrous ions (Fe2+) sustains the enzymatic activity. Using SCD1 labeled with Fe isotope, we further show that free Fe2+ is incorporated into the diiron center only during catalysis. We also discover that the diiron center in SCD1 has prominent electron paramagnetic resonance signals in its diferric state, indicative of distinct coupling between the two ferric ions. These results reveal that the diiron center in SCD1 is structurally dynamic during catalysis and that labile Fe2+ in cells could regulate SCD1 activity, and hence lipid metabolism.
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Affiliation(s)
- Jiemin Shen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gang Wu
- Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX 77030, USA.
| | - Brad S Pierce
- Department of Chemistry & Biochemistry, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Ah-Lim Tsai
- Department of Internal Medicine, University of Texas McGovern Medical School, Houston, TX 77030, USA.
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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46
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Suremann NF, McCarthy BD, Gschwind W, Kumar A, Johnson BA, Hammarström L, Ott S. Molecular Catalysis of Energy Relevance in Metal-Organic Frameworks: From Higher Coordination Sphere to System Effects. Chem Rev 2023; 123:6545-6611. [PMID: 37184577 DOI: 10.1021/acs.chemrev.2c00587] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The modularity and synthetic flexibility of metal-organic frameworks (MOFs) have provoked analogies with enzymes, and even the term MOFzymes has been coined. In this review, we focus on molecular catalysis of energy relevance in MOFs, more specifically water oxidation, oxygen and carbon dioxide reduction, as well as hydrogen evolution in context of the MOF-enzyme analogy. Similar to enzymes, catalyst encapsulation in MOFs leads to structural stabilization under turnover conditions, while catalyst motifs that are synthetically out of reach in a homogeneous solution phase may be attainable as secondary building units in MOFs. Exploring the unique synthetic possibilities in MOFs, specific groups in the second and third coordination sphere around the catalytic active site have been incorporated to facilitate catalysis. A key difference between enzymes and MOFs is the fact that active site concentrations in the latter are often considerably higher, leading to charge and mass transport limitations in MOFs that are more severe than those in enzymes. High catalyst concentrations also put a limit on the distance between catalysts, and thus the available space for higher coordination sphere engineering. As transport is important for MOF-borne catalysis, a system perspective is chosen to highlight concepts that address the issue. A detailed section on transport and light-driven reactivity sets the stage for a concise review of the currently available literature on utilizing principles from Nature and system design for the preparation of catalytic MOF-based materials.
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Affiliation(s)
- Nina F Suremann
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Brian D McCarthy
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Wanja Gschwind
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Amol Kumar
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Ben A Johnson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
- Technical University Munich (TUM), Campus Straubing for Biotechnology and Sustainability, Uferstraße 53, 94315 Straubing, Germany
| | - Leif Hammarström
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Sascha Ott
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
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47
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D'Alonzo D, De Fenza M, Pavone V, Lombardi A, Nastri F. Selective Oxidation of Halophenols Catalyzed by an Artificial Miniaturized Peroxidase. Int J Mol Sci 2023; 24:ijms24098058. [PMID: 37175773 PMCID: PMC10178546 DOI: 10.3390/ijms24098058] [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: 03/27/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
The development of artificial enzymes for application in sustainable technologies, such as the transformation of environmental pollutants or biomass, is one of the most challenging goals in metalloenzyme design. In this work, we describe the oxidation of mono-, di-, tri- and penta-halogenated phenols catalyzed by the artificial metalloenzyme Fe-MC6*a. It promoted the dehalogenation of 4-fluorophenol into the corresponding 1,4-benzoquinone, while under the same experimental conditions, 4-chloro, 4-bromo and 4-iodophenol were selectively converted into higher molecular weight compounds. Analysis of the 4-chlorophenol oxidation products clarified that oligomers based on C-O bonds were exclusively formed in this case. All results show that Fe-MC6*a holds intriguing enzymatic properties, as it catalyzes halophenol oxidation with substrate-dependent chemoselectivity.
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Affiliation(s)
- Daniele D'Alonzo
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Maria De Fenza
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Vincenzo Pavone
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Angela Lombardi
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Flavia Nastri
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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48
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Ortega P, Gil-Guerrero S, González-Sánchez L, Sanz-Sanz C, Jambrina PG. Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates-Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid. Int J Mol Sci 2023; 24:ijms24087424. [PMID: 37108586 PMCID: PMC10138960 DOI: 10.3390/ijms24087424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.
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Affiliation(s)
- Pablo Ortega
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Sara Gil-Guerrero
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
- CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Cristina Sanz-Sanz
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pablo G Jambrina
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
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49
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Jeong D, Selverstone Valentine J, Cho J. Bio-inspired mononuclear nonheme metal peroxo complexes: Synthesis, structures and mechanistic studies toward understanding enzymatic reactions. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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50
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Ji L, Zhang H, Ding W, Song R, Han Y, Yu H, Paneth P. Theoretical Kinetic Isotope Effects in Establishing the Precise Biodegradation Mechanisms of Organic Pollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:4915-4929. [PMID: 36926881 DOI: 10.1021/acs.est.2c04755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Compound-specific isotope analysis (CSIA) for natural isotope ratios has been recognized as a promising tool to elucidate biodegradation pathways of organic pollutants by microbial enzymes by relating reported kinetic isotope effects (KIEs) to apparent KIEs (AKIEs) derived from bulk isotope fractionations (εbulk). However, for many environmental reactions, neither are the reference KIE ranges sufficiently narrow nor are the mechanisms elucidated to the point that rate-determining steps have been identified unequivocally. In this work, besides providing reference KIEs and rationalizing AKIEs, good relationships have been explained by DFT computations for diverse biodegradation pathways with known enzymatic models between the theoretical isotope fractionations (εbulk') from intrinsic KIEs on the rate-determining steps and the observed εbulk. (1) To confirm the mechanistic details of previously reported pathway-dependent CSIA, it includes isotope changes in MTBE biodegradation between hydroxylation by CYP450 and SN2 reaction by cobalamin-dependent methyltransferase, the regioselectivity of toluene biodegradation by CYP450, and the rate-determining step in toluene biodegradation by benzylsuccinate synthase. (2) To yield new fundamental insights into some unclear biodegradation pathways, it consists of the oxidative function of toluene dioxygenase in biodegradation of TCE, the epoxidation mode in biodegradation of TCE by toluene 4-monooxygenase, and the weighted average mechanism in biodegradation of cDCE by CYP450.
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Affiliation(s)
- Li Ji
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Daxue Road 1, Xuzhou 221116, China
| | - Huanni Zhang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Daxue Road 1, Xuzhou 221116, China
- College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Wen Ding
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Daxue Road 1, Xuzhou 221116, China
| | - Runqian Song
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Daxue Road 1, Xuzhou 221116, China
- College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Ye Han
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Daxue Road 1, Xuzhou 221116, China
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Piotr Paneth
- Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, Lodz 90-924, Poland
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