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Hardy FG, Wong HPH, de Visser SP. Computational Study Into the Oxidative Ring-Closure Mechanism During the Biosynthesis of Deoxypodophyllotoxin. Chemistry 2024; 30:e202400019. [PMID: 38323740 DOI: 10.1002/chem.202400019] [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: 01/03/2024] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/08/2024]
Abstract
The nonheme iron dioxygenase deoxypodophyllotoxin synthase performs an oxidative ring-closure reaction as part of natural product synthesis in plants. How the enzyme enables the oxidative ring-closure reaction of (-)-yatein and avoids substrate hydroxylation remains unknown. To gain insight into the reaction mechanism and understand the details of the pathways leading to products and by-products we performed a comprehensive computational study. The work shows that substrate is bound tightly into the substrate binding pocket with the C7'-H bond closest to the iron(IV)-oxo species. The reaction proceeds through a radical mechanism starting with hydrogen atom abstraction from the C7'-H position followed by ring-closure and a final hydrogen transfer to form iron(II)-water and deoxypodophyllotoxin. Alternative mechanisms including substrate hydroxylation and an electron transfer pathway were explored but found to be higher in energy. The mechanism is guided by electrostatic perturbations of charged residues in the second-coordination sphere that prevent alternative pathways.
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Affiliation(s)
- Fintan G Hardy
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
- Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Henrik P H Wong
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
- Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Sam P de Visser
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
- Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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2
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Mei S, Ou Q, Tang X, Xu JF, Zhang X. Stabilization of Carbocation Intermediate by Cucurbit[7]uril Enables High Photolysis Efficiency. Org Lett 2023; 25:5291-5296. [PMID: 37428144 DOI: 10.1021/acs.orglett.3c01854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
A cucurbit[7]uril-based host-guest strategy is employed to enhance the efficiency of photolysis reactions that release caged molecules from photoremovable protecting groups. The photolysis of benzyl acetate follows a heterolytic bond cleavage mechanism, thereby leading to the formation of a contact ion pair as the key reactive intermediate. The Gibbs free energy of the contact ion pair is lowered by 3.06 kcal/mol through the stabilization of cucurbit[7]uril, as revealed by DFT calculations, which results in a 40-fold increase in the quantum yield of the photolysis reaction. This methodology is also applicable to the chloride leaving group and the diphenyl photoremovable protecting group. We anticipate that this research presents a novel strategy to improve reactions involving active cationics, thereby enriching the field of supramolecular catalysis.
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Affiliation(s)
- Shan Mei
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qi Ou
- AI for Science Institute, Beijing 100080, China
- DP Technology, Beijing 100080, China
| | - Xingchen Tang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jiang-Fei Xu
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xi Zhang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
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3
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Rad N, Sashuk V. Effect of Na + and K + on the cucurbituril-mediated hydrolysis of a phenyl acetate. Chem Commun (Camb) 2022; 58:5249-5252. [PMID: 35388837 DOI: 10.1039/d2cc00772j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The environment around the active site affects the catalytic activity of enzymes. Studying the cucurbit[7]uril-promoted acid hydrolysis of a cationic phenyl acetate derivative, we found that the hydrophobic cavity of the macrocycle screens the reaction centre from the positively charged neighbouring group. Moreover, the chelation of alkali metal cations with the cucurbit[7]uril portal and acetyl group of the substrate reduces the hydrolysis rate of the encapsulated ester in an aqueous solution. This type of inhibition corresponds to a rare uncompetitive model in contrast to the more common competitive model that relies on substrate displacement.
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Affiliation(s)
- Nazar Rad
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Volodymyr Sashuk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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4
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Jin Y, Li M, Liu M, Ge Q, Cong H, Tao Z. Cucurbit[7]uril‐Catalyzed Controllable Pinacol Rearrangement with Activated Hydride Migration. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ye Jin
- Guizhou University Enterprise Technology Center of Guizhou Province CHINA
| | - Min Li
- Guizhou University Enterprise Technology Center of Guizhou Province CHINA
| | - Mao Liu
- Guizhou University Enterprise Technology Center of Guizhou Province CHINA
| | - Qingmei Ge
- Guizhou University Enterprise Technology Center of Guizhou Province Huaxi district 550025 Guiyang CHINA
| | - Hang Cong
- Guizhou University Enterprise Technology Center of Guizhou Province CHINA
| | - Zhu Tao
- Guizhou University Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province CHINA
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5
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Rad N, Sashuk V. A light-gated regulation of the reaction site by a cucurbit[7]uril macrocycle. Chem Sci 2022; 13:12440-12444. [DOI: 10.1039/d2sc02077g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 10/10/2022] [Indexed: 11/21/2022] Open
Abstract
On–off competitive inhibition is presented. Photoswitchable pseudorotaxane controls the rate of self-reaction and product selectivity of external reactions.
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Affiliation(s)
- Nazar Rad
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Volodymyr Sashuk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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6
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Negative catalysis / non-Bell-Evans-Polanyi reactivity by metalloenzymes: Examples from mononuclear heme and non-heme iron oxygenases. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213914] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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7
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Lin YT, Ali HS, de Visser SP. Electrostatic Perturbations from the Protein Affect C-H Bond Strengths of the Substrate and Enable Negative Catalysis in the TmpA Biosynthesis Enzyme. Chemistry 2021; 27:8851-8864. [PMID: 33978257 DOI: 10.1002/chem.202100791] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/08/2022]
Abstract
The nonheme iron dioxygenase 2-(trimethylammonio)-ethylphosphonate dioxygenase (TmpA) is an enzyme involved in the regio- and chemoselective hydroxylation at the C1 -position of the substrate as part of the biosynthesis of glycine betaine in bacteria and carnitine in humans. To understand how the enzyme avoids breaking the weak C2 -H bond in favor of C1 -hydroxylation, we set up a cluster model of 242 atoms representing the first and second coordination sphere of the metal center and substrate binding pocket, and investigated possible reaction mechanisms of substrate activation by an iron(IV)-oxo species by density functional theory methods. In agreement with experimental product distributions, the calculations predict a favorable C1 -hydroxylation pathway. The calculations show that the selectivity is guided through electrostatic perturbations inside the protein from charged residues, external electric fields and electric dipole moments. In particular, charged residues influence and perturb the homolytic bond strength of the C1 -H and C2 -H bonds of the substrate, and strongly strengthens the C2 -H bond in the substrate-bound orientation.
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Affiliation(s)
- Yen-Ting Lin
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Hafiz Saqib Ali
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Sam P de Visser
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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8
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Goswami A, Gaikwad S, Schmittel M. A Switchable Catalyst Duo for Acyl Transfer Proximity Catalysis and Regulation of Substrate Selectivity. Chemistry 2021; 27:2997-3001. [PMID: 33022776 PMCID: PMC7898682 DOI: 10.1002/chem.202004416] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Indexed: 12/15/2022]
Abstract
Enzymes are encoded with a gamut of information to catalyze a highly selective transformation by selecting the proper reactants from an intricate mixture of constituents. Mimicking biological machinery, two switchable catalysts with differently sized cavities and allosteric control are conceived that allow complementary size-selective acyl transfer in an on/off manner by modulating the effective local concentration of the substrates. Selective activation of one of two catalysts in a mixture of reactants of similar reactivity enabled upregulation of the desired product.
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Affiliation(s)
- Abir Goswami
- Center of Micro and Nanochemistry and Engineering, Organische Chemie IUniversity of SiegenAdolf-Reichwein Str. 257068SiegenGermany
| | - Sudhakar Gaikwad
- Center of Micro and Nanochemistry and Engineering, Organische Chemie IUniversity of SiegenAdolf-Reichwein Str. 257068SiegenGermany
| | - Michael Schmittel
- Center of Micro and Nanochemistry and Engineering, Organische Chemie IUniversity of SiegenAdolf-Reichwein Str. 257068SiegenGermany
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9
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Tang B, Zhao J, Xu J, Zhang X. Cucurbit[
n
]urils for Supramolecular Catalysis. Chemistry 2020; 26:15446-15460. [DOI: 10.1002/chem.202003897] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/08/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Bohan Tang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Jiantao Zhao
- Key Laboratory of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Jiang‐Fei Xu
- Key Laboratory of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Xi Zhang
- Key Laboratory of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 P. R. China
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10
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Berta D, Szabó I, Scherman OA, Rosta E. Toward Understanding CB[7]-Based Supramolecular Diels-Alder Catalysis. Front Chem 2020; 8:587084. [PMID: 33240848 PMCID: PMC7677497 DOI: 10.3389/fchem.2020.587084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/28/2020] [Indexed: 11/16/2022] Open
Abstract
Cucurbiturils (CBs) are robust and versatile macrocyclic compounds, often used as molecular hosts in complex supramolecular systems. In previous work, remarkable catalytic activity has been observed for asymmetric cycloadditions under very mild conditions. Herein, we investigate the nature of supramolecular catalysis using DFT calculations and QM/MM techniques. We discuss induced conformational changes, electrostatic shielding effects from the highly polar aqueous environment and cooperativity in hydrogen bonding of the substrates in explicit water using QM/MM simulation techniques. Our results show little specificity for the chosen molecules, suggesting an excellent opportunity to expand the scope for catalytic use of these supramolecular macrocyclic containers.
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Affiliation(s)
- Dénes Berta
- Department of Physics and Astronomy, University College London, London, United Kingdom.,Department of Chemistry, King's College London, London, United Kingdom
| | - István Szabó
- Department of Chemistry, King's College London, London, United Kingdom
| | - Oren A Scherman
- Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Edina Rosta
- Department of Physics and Astronomy, University College London, London, United Kingdom.,Department of Chemistry, King's College London, London, United Kingdom
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11
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Affiliation(s)
- Sandra Kosiorek
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Nazar Rad
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Volodymyr Sashuk
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
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12
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Niedek D, Erb FR, Topp C, Seitz A, Wende RC, Eckhardt AK, Kind J, Herold D, Thiele CM, Schreiner PR. In Situ Switching of Site-Selectivity with Light in the Acetylation of Sugars with Azopeptide Catalysts. J Org Chem 2020; 85:1835-1846. [PMID: 31763833 DOI: 10.1021/acs.joc.9b01913] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We present a novel concept for the in situ control of site-selectivity of catalytic acetylations of partially protected sugars using light as external stimulus and oligopeptide catalysts equipped with an azobenzene moiety. The isomerizable azobenzene-peptide backbone defines the size and shape of the catalytic pocket, while the π-methyl-l-histidine (Pmh) moiety transfers the electrophile. Photoisomerization of the E- to the Z-azobenzene catalyst (monitored via NMR) with an LED (λ = 365 nm) drastically changes the chemical environment around the catalytically active Pmh moiety, so that the light-induced change in the catalyst shape alters site-selectivity. As a proof of principle, we employed (4,6-O-benzylidene)methyl-α-d-pyranosides, which provide a change in regioselectivity from 2:1 (E) to 1:5 (Z) for the monoacetylated products at room temperature. The validity of this new catalyst-design concept is further demonstrated with the regioselective acetylation of the natural product quercetin. In situ irradiation NMR spectroscopy was used to quantify photostationary states under continuous irradiation with UV light.
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Affiliation(s)
- Dominik Niedek
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Frederik R Erb
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Christopher Topp
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Alexander Seitz
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Raffael C Wende
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - André K Eckhardt
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Jonas Kind
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie , Technische Universität Darmstadt , Alarich-Weiss-Str. 16 , 64287 Darmstadt , Germany
| | - Dominik Herold
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie , Technische Universität Darmstadt , Alarich-Weiss-Str. 16 , 64287 Darmstadt , Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie , Technische Universität Darmstadt , Alarich-Weiss-Str. 16 , 64287 Darmstadt , Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
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