1
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Su Y, Lai W. Unraveling the Mechanism of the Oxidative C-C Bond Coupling Reaction Catalyzed by Deoxypodophyllotoxin Synthase. Inorg Chem 2024; 63:13948-13958. [PMID: 39008659 DOI: 10.1021/acs.inorgchem.4c01263] [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: 07/17/2024]
Abstract
Deoxypodophyllotoxin synthase (DPS), a nonheme Fe(II)/2-oxoglutarate (2OG)-dependent oxygenase, is a key enzyme that is involved in the construction of the fused-ring system in (-)-podophyllotoxin biosynthesis by catalyzing the C-C coupling reaction. However, the mechanistic details of DPS-catalyzed ring formation remain unclear. Herein, our quantum mechanics/molecular mechanics (QM/MM) calculations reveal a novel mechanism that involves the recycling of CO2 (a product of decarboxylation of 2OG) to prevent the formation of hydroxylated byproducts. Our results show that CO2 can react with the FeIII-OH species to generate an unusual FeIII-bicarbonate species. In this way, hydroxylation is avoided by consuming the OH group. Then, the C-C coupling followed by desaturation yields the final product, deoxypodophyllotoxin. This work highlights the crucial role of the CO2 molecule, generated in the crevice between the iron active site and the substrate, in controlling the reaction selectivity.
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Affiliation(s)
- Yanzhuang Su
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
| | - Wenzhen Lai
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China
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2
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Meng F, Sun L, Liu Y, Li X, Tan H, Yuan C, Li X. Theoretical investigation of the reaction mechanism of THP oxidative rearrangement catalysed by BBOX. Phys Chem Chem Phys 2024. [PMID: 39015023 DOI: 10.1039/d4cp01661k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
γ-Butyrobetaine hydroxylase (BBOX) is a non-heme FeII/2OG dependent enzyme that is able to perform two different kinds of catalytic reactions on 3-(2,2,2-trimethylhydrazinium) propionate (THP) to produce distinct catalytic products. Although the structure of BBOX complexed with THP has been resolved, the details of its catalytic mechanism are still elusive. In this study, by employing molecular dynamics (MD) simulations and density functional theory (DFT) calculations, the mechanism of the THP oxidative rearrangement reactions catalysed by BBOX was investigated. Our calculations revealed how the enzyme undergoes a conformational conversion to initiate the catalytic reactions. In the first catalytic step, BBOX performs hydrogen abstraction from the substrate THP as a common non-heme iron enzyme. Due to the structure of the substrate stabilizing the radical species and polarizing the adjacent N-N bond, in the next step, THP takes the pathway for N-N bond homolysis but not regular hydroxyl rebounding. The cleaved ammonium radical could either react with the hydroxyl group on the iron centre of the enzyme or recombine with the other cleaved fragment of the substrate to generate the rearranged product. This study revealed the catalytic mechanism of BBOX, detailing how the enzyme and the substrate regulated the hydroxyl rebound process to generate various products.
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Affiliation(s)
- Fanqi Meng
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Lu Sun
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Yueying Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Xiang Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Hongwei Tan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Chang Yuan
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Xichen Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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3
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Pan J, Wenger ES, Lin CY, Zhang B, Sil D, Schaperdoth I, Saryazdi S, Grossman RB, Krebs C, Bollinger JM. An Unusual Ferryl Intermediate and Its Implications for the Mechanism of Oxacyclization by the Loline-Producing Iron(II)- and 2-Oxoglutarate-Dependent Oxygenase, LolO. Biochemistry 2024; 63:1674-1683. [PMID: 38898603 PMCID: PMC11219260 DOI: 10.1021/acs.biochem.4c00166] [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: 06/21/2024]
Abstract
N-Acetylnorloline synthase (LolO) is one of several iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases that catalyze sequential reactions of different types in the biosynthesis of valuable natural products. LolO hydroxylates C2 of 1-exo-acetamidopyrrolizidine before coupling the C2-bonded oxygen to C7 to form the tricyclic loline core. Each reaction requires cleavage of a C-H bond by an oxoiron(IV) (ferryl) intermediate; however, different carbons are targeted, and the carbon radicals have different fates. Prior studies indicated that the substrate-cofactor disposition (SCD) controls the site of H· abstraction and can affect the reaction outcome. These indications led us to determine whether a change in SCD from the first to the second LolO reaction might contribute to the observed reactivity switch. Whereas the single ferryl complex in the C2 hydroxylation reaction was previously shown to have typical Mössbauer parameters, one of two ferryl complexes to accumulate during the oxacyclization reaction has the highest isomer shift seen to date for such a complex and abstracts H· from C7 ∼ 20 times faster than does the first ferryl complex in its previously reported off-pathway hydroxylation of C7. The detectable hydroxylation of C7 in competition with cyclization by the second ferryl complex is not enhanced in 2H2O solvent, suggesting that the C2 hydroxyl is deprotonated prior to C7-H cleavage. These observations are consistent with the coordination of the C2 oxygen to the ferryl complex, which may reorient its oxo ligand, the substrate, or both to positions more favorable for C7-H cleavage and oxacyclization.
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Affiliation(s)
- Juan Pan
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Present address: New England Biolabs, Ipswich, Massachusetts 01938, United States
| | - Eliott S. Wenger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Present address: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Chi-Yun Lin
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Present address: The Janssen Pharmaceutical Companies of Johnson & Johnson, Spring House, Pennsylvania 19477, United States
| | - Debangsu Sil
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Present address: Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Irene Schaperdoth
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Present address: Department of Engineering, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Setareh Saryazdi
- Department of Chemistry, The University of Kentucky, Lexington, Kentucky 40506, United States
- Present address: College of Pharmacy, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Robert B. Grossman
- Department of Chemistry, The University of Kentucky, Lexington, Kentucky 40506, United States
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - J. Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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4
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Thomas M, Jaber Sathik Rifayee SB, Chaturvedi SS, Gorantla KR, White W, Wildey J, Schofield CJ, Christov CZ. The Unique Role of the Second Coordination Sphere to Unlock and Control Catalysis in Nonheme Fe(II)/2-Oxoglutarate Histone Demethylase KDM2A. Inorg Chem 2024; 63:10737-10755. [PMID: 38781256 PMCID: PMC11168414 DOI: 10.1021/acs.inorgchem.4c01365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/26/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024]
Abstract
Nonheme Fe(II) and 2-oxoglutarate (2OG)-dependent histone lysine demethylases 2A (KDM2A) catalyze the demethylation of the mono- or dimethylated lysine 36 residue in the histone H3 peptide (H3K36me1/me2), which plays a crucial role in epigenetic regulation and can be involved in many cancers. Although the overall catalytic mechanism of KDMs has been studied, how KDM2 catalysis takes place in contrast to other KDMs remains unknown. Understanding such differences is vital for enzyme redesign and can help in enzyme-selective drug design. Herein, we employed molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) to explore the complete catalytic mechanism of KDM2A, including dioxygen diffusion and binding, dioxygen activation, and substrate oxidation. Our study demonstrates that the catalysis of KDM2A is controlled by the conformational change of the second coordination sphere (SCS), specifically by a change in the orientation of Y222, which unlocks the 2OG rearrangement from off-line to in-line mode. The study demonstrates that the variant Y222A makes the 2OG rearrangement more favorable. Furthermore, the study reveals that it is the size of H3K36me3 that prevents the 2OG rearrangement, thus rendering the enzyme inactivity with trimethylated lysine. Calculations show that the SCS and long-range interacting residues that stabilize the HAT transition state in KDM2A differ from those in KDM4A, KDM7B, and KDM6A, thus providing the basics for the enzyme-selective redesign and modulation of KDM2A without influencing other KDMs.
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Affiliation(s)
- Midhun
George Thomas
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
| | | | - Shobhit S. Chaturvedi
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
| | - Koteswara Rao Gorantla
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
| | - Walter White
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
| | - Jon Wildey
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
| | - Christopher J. Schofield
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12, Mansfield Road, Oxford OX1 5JJ, U.K.
| | - Christo Z. Christov
- Department
of Chemistry, and Department of Chemical Engineering, Michigan
Technological University, Houghton, Michigan 49931, United States
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5
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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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6
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Li RN, Chen SL. Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin. Chemistry 2024; 30:e202303845. [PMID: 38212866 DOI: 10.1002/chem.202303845] [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: 11/19/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of μ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.
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Affiliation(s)
- Rui-Ning Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
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7
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Jaber Sathik Rifayee SB, Chaturvedi SS, Warner C, Wildey J, White W, Thompson M, Schofield CJ, Christov CZ. Catalysis by KDM6 Histone Demethylases - A Synergy between the Non-Heme Iron(II) Center, Second Coordination Sphere, and Long-Range Interactions. Chemistry 2023; 29:e202301305. [PMID: 37258457 PMCID: PMC10526731 DOI: 10.1002/chem.202301305] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/02/2023]
Abstract
KDM6A (UTX) and KDM6B (JMJD3) are human non-heme Fe(II) and 2-oxoglutarate (2OG) dependent JmjC oxygenases that catalyze the demethylation of trimethylated lysine 27 in the N-terminal tail of histone H3, a post-translational modification that regulates transcription. A Combined Quantum Mechanics/ Molecular Mechanics (QM/MM) and Molecular Dynamics (MD) study on the catalytic mechanism of KDM6A/B reveals that the transition state for the rate-limiting hydrogen atom transfer (HAT) reaction in KDM6A catalysis is stabilized by polar (Asn217) and aromatic (Trp369)/non-polar (Pro274) residues in contrast to KDM4, KDM6B and KDM7 demethylases where charged residues (Glu, Arg, Asp) are involved. KDM6A employs both σ- and π-electron transfer pathways for HAT, whereas KDM6B employs the σ-electron pathway. Differences in hydrogen bonding of the Fe-chelating Glu252(KDM6B) contribute to the lower energy barriers in KDM6B vs. KDM6A. The study reveals a dependence of the activation barrier of the rebound hydroxylation on the Fe-O-C angle in the transition state of KDM6A. Anti-correlation of the Zn-binding domain with the active site residues is a key factor distinguishing KDM6A/B from KDM7/4s. The results reveal the importance of communication between the Fe center, second coordination sphere, and long-range interactions in catalysis by KDMs and, by implication, other 2OG oxygenases.
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Affiliation(s)
| | | | - Cait Warner
- Department of Biological Sciences, Michigan Technological University, Houghton, MI-49931, USA
| | - Jon Wildey
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI-49931, USA
| | - Walter White
- Department of Chemistry, Michigan Technological University, Houghton, MI-49931, USA
| | - Martin Thompson
- Department of Chemistry, Michigan Technological University, Houghton, MI-49931, USA
| | - Christopher J. Schofield
- Chemistry Research laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, MI-49931, USA
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8
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Awakawa T, Mori T, Ushimaru R, Abe I. Structure-based engineering of α-ketoglutarate dependent oxygenases in fungal meroterpenoid biosynthesis. Nat Prod Rep 2023; 40:46-61. [PMID: 35642933 DOI: 10.1039/d2np00014h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Non-heme iron- and α-ketoglutarate-dependent oxygenases (αKG OXs) are key enzymes that play a major role in diversifying the structure of fungal meroterpenoids. They activate a specific C-H bond of the substrate to first generate radical species, which is usually followed by oxygen rebound to produce cannonical hydroxylated products. However, in some cases remarkable chemistry induces dramatic structural changes in the molecular scaffolds, depending on the stereoelectronic characters of the substrate/intermediates and the resulting conformational changes/movements of the active site of the enzyme. Their molecular bases have been extensively investigated by crystallographic structural analyses and structure-based mutagenesis, which revealed intimate structural details of the enzyme reactions. This information facilitates the manipulation of the enzyme reactions to create unnatural, novel molecules for drug discovery. This review summarizes recent progress in the structure-based engineering of αKG OX enzymes, involved in the biosynthesis of polyketide-derived fungal meroterpenoids. The literature published from 2016 through February 2022 is reviewed.
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Affiliation(s)
- Takayoshi Awakawa
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. .,Collaborative Research Institute for Innovative Microbiology, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takahiro Mori
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. .,Collaborative Research Institute for Innovative Microbiology, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Richiro Ushimaru
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. .,Collaborative Research Institute for Innovative Microbiology, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.,ACT-X, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. .,Collaborative Research Institute for Innovative Microbiology, the University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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9
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Auman D, Ecker F, Mader SL, Dorst KM, Bräuer A, Widmalm G, Groll M, Kaila VRI. Peroxy Intermediate Drives Carbon Bond Activation in the Dioxygenase AsqJ. J Am Chem Soc 2022; 144:15622-15632. [PMID: 35980821 DOI: 10.1021/jacs.2c05650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dioxygenases catalyze stereoselective oxygen atom transfer in metabolic pathways of biological, industrial, and pharmaceutical importance, but their precise chemical principles remain controversial. The α-ketoglutarate (αKG)-dependent dioxygenase AsqJ synthesizes biomedically active quinolone alkaloids via desaturation and subsequent epoxidation of a carbon-carbon bond in the cyclopeptin substrate. Here, we combine high-resolution X-ray crystallography with enzyme engineering, quantum-classical (QM/MM) simulations, and biochemical assays to describe a peroxidic intermediate that bridges the substrate and active site metal ion in AsqJ. Homolytic cleavage of this moiety during substrate epoxidation generates an activated high-valent ferryl (FeIV = O) species that mediates the next catalytic cycle, possibly without the consumption of the metabolically valuable αKG cosubstrate. Our combined findings provide an important understanding of chemical bond activation principles in complex enzymatic reaction networks and molecular mechanisms of dioxygenases.
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Affiliation(s)
- Dirk Auman
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Felix Ecker
- Center for Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748 Garching, Germany
| | - Sophie L Mader
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Kevin M Dorst
- Department of Organic Chemistry, Stockholm University, 10691 Stockholm, Sweden
| | - Alois Bräuer
- Center for Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748 Garching, Germany
| | - Göran Widmalm
- Department of Organic Chemistry, Stockholm University, 10691 Stockholm, Sweden
| | - Michael Groll
- Center for Protein Assemblies, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748 Garching, Germany
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
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10
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Waheed SO, Varghese A, Chaturvedi SS, Karabencheva-Christova TG, Christov CZ. How Human TET2 Enzyme Catalyzes the Oxidation of Unnatural Cytosine Modifications in Double-Stranded DNA. ACS Catal 2022; 12:5327-5344. [PMID: 36339349 PMCID: PMC9629818 DOI: 10.1021/acscatal.2c00024] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methylation of cytosine bases is strongly linked to gene expression, imprinting, aging, and carcinogenesis. The Ten-eleven translocation (TET) family of enzymes, which are Fe(II)/2-oxoglutarate (2OG)-dependent enzymes, employ Fe(IV)=O species to dealkylate the lesioned bases to an unmodified cytosine. Recently, it has been shown that the TET2 enzyme can catalyze promiscuously DNA substrates containing unnatural alkylated cytosine. Such unnatural substrates of TET can be used as direct probes for measuring the TET activity or capturing TET from cellular samples. Herein, we studied the catalytic mechanisms during the oxidation of the unnatural C5-position modifications (5-ethylcytosine (5eC), 5-vinylcytosine (5vC) and 5-ethynylcytosine (5eyC)) and the demethylation of N4-methylated lesions (4-methylcytosine (4mC) and 4,4-dimethylcytosine(4dmC)) of the cytosine base by the TET2 enzyme using molecular dynamics (MD) and combined quantum mechanics and molecular mechanics (QM/MM) computational approaches. The results reveal that the chemical nature of the alkylation of the double-stranded (ds) DNA substrates induces distinct changes in the interactions in the binding site, the second coordination sphere, and long-range correlated motions of the ES complexes. The rate-determining hydrogen atom transfer (HAT) is faster in N4-methyl substituent substrates than in the C5-alkylations. Importantly, the calculations show the preference of hydroxylation over desaturation in both 5eC and 5vC substrates. The studies elucidate the post-hydroxylation rearrangements of the hydroxylated intermediates of 5eyC and 5vC to ketene and 5-formylmethylcytosine (5fmC), respectively, and hydrolysis of hemiaminal intermediate of 4mC to formaldehyde and unmodified cytosine proceed exclusively in aqueous solution outside of the enzyme environment. Overall, the studies show that the chemical nature of the unnatural alkylated cytosine substrates exercises distinct effects on the binding interactions, reaction mechanism, and dynamics of TET2.
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Affiliation(s)
- Sodiq O. Waheed
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Ann Varghese
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Shobhit S. Chaturvedi
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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11
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Wojdyla Z, Borowski T. Properties of the Reactants and Their Interactions within and with the Enzyme Binding Cavity Determine Reaction Selectivities. The Case of Fe(II)/2-Oxoglutarate Dependent Enzymes. Chemistry 2022; 28:e202104106. [PMID: 34986268 DOI: 10.1002/chem.202104106] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 12/12/2022]
Abstract
Fe(II)/2-oxoglutarate dependent dioxygenases (ODDs) share a double stranded beta helix (DSBH) fold and utilise a common reactive intermediate, ferryl species, to catalyse oxidative transformations of substrates. Despite the structural similarities, ODDs accept a variety of substrates and facilitate a wide range of reactions, that is hydroxylations, desaturations, (oxa)cyclisations and ring rearrangements. In this review we present and discuss the factors contributing to the observed (regio)selectivities of ODDs. They span from inherent properties of the reactants, that is, substrate molecule and iron cofactor, to the interactions between the substrate and the enzyme's binding cavity; the latter can counterbalance the effect of the former. Based on results of both experimental and computational studies dedicated to ODDs, we also line out the properties of the reactants which promote reaction outcomes other than the "default" hydroxylation. It turns out that the reaction selectivity depends on a delicate balance of interactions between the components of the investigated system.
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Affiliation(s)
- Zuzanna Wojdyla
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Niezapominajek 8, 30239 Krakow, Poland
| | - Tomasz Borowski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Niezapominajek 8, 30239 Krakow, Poland
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12
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Ramanan R, Waheed SO, Schofield CJ, Christov CZ. What Is the Catalytic Mechanism of Enzymatic Histone N-Methyl Arginine Demethylation and Can It Be Influenced by an External Electric Field? Chemistry 2021; 27:11827-11836. [PMID: 33989435 PMCID: PMC9212892 DOI: 10.1002/chem.202101174] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Indexed: 11/11/2022]
Abstract
Arginine methylation is an important mechanism of epigenetic regulation. Some Fe(II) and 2-oxoglutarate dependent Jumonji-C (JmjC) Nϵ-methyl lysine histone demethylases also have N-methyl arginine demethylase activity. We report combined molecular dynamic (MD) and Quantum Mechanical/Molecular Mechanical (QM/MM) studies on the mechanism of N-methyl arginine demethylation by human KDM4E and compare the results with those reported for N-methyl lysine demethylation by KDM4A. At the KDM4E active site, Glu191, Asn291, and Ser197 form a conserved scaffold that restricts substrate dynamics; substrate binding is also mediated by an out of active site hydrogen-bond between the substrate Ser1 and Tyr178. The calculations imply that in either C-H or N-H potential bond cleaving pathways for hydrogen atom transfer (HAT) during N-methyl arginine demethylation, electron transfer occurs via a σ-channel; the transition state for the N-H pathway is ∼10 kcal/mol higher than for the C-H pathway due to the higher bond dissociation energy of the N-H bond. The results of applying external electric fields (EEFs) reveal EEFs with positive field strengths parallel to the Fe=O bond have a significant barrier-lowering effect on the C-H pathway, by contrast, such EEFs inhibit the N-H activation rate. The overall results imply that KDM4 catalyzed N-methyl arginine demethylation and N-methyl lysine demethylation occur via similar C-H abstraction and rebound mechanisms leading to methyl group hydroxylation, though there are differences in the interactions leading to productive binding of intermediates.
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Affiliation(s)
- Rajeev Ramanan
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
- Present address: Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769001, India
| | - Sodiq O. Waheed
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Christopher J. Schofield
- The Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, The Chemistry Research Laboratory, Mansfield Road, University of Oxford, OX1 5JJ, United Kingdom
| | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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13
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Yeh CCG, Pierides C, Jameson GNL, de Visser SP. Structure and Functional Differences of Cysteine and 3-Mercaptopropionate Dioxygenases: A Computational Study. Chemistry 2021; 27:13793-13806. [PMID: 34310770 DOI: 10.1002/chem.202101878] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 11/09/2022]
Abstract
Thiol dioxygenases are important enzymes for human health; they are involved in the detoxification and catabolism of toxic thiol-containing natural products such as cysteine. As such, these enzymes have relevance to the development of Alzheimer's and Parkinson's diseases in the brain. Recent crystal structure coordinates of cysteine and 3-mercaptopropionate dioxygenase (CDO and MDO) showed major differences in the second-coordination spheres of the two enzymes. To understand the difference in activity between these two analogous enzymes, we created large, active-site cluster models. We show that CDO and MDO have different iron(III)-superoxo-bound structures due to differences in ligand coordination. Furthermore, our studies show that the differences in the second-coordination sphere and particularly the position of a positively charged Arg residue results in changes in substrate positioning, mobility and enzymatic turnover. Furthermore, the substrate scope of MDO is explored with cysteinate and 2-mercaptosuccinic acid and their reactivity is predicted.
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Affiliation(s)
- C-C George Yeh
- 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
| | - Christos Pierides
- 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
| | - Guy N L Jameson
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Vic, 3010, Australia
| | - 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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14
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Singh W, Hui C, Li C, Huang M. Thebaine is Selectively Demethylated by Thebaine 6- O-Demethylase and Codeine-3- O-demethylase at Distinct Binding Sites: A Computational Study. Inorg Chem 2021; 60:10199-10214. [PMID: 34213893 DOI: 10.1021/acs.inorgchem.1c00468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Two homologous 2-oxoglutarate-dependent (ODD) nonheme enzymes thebaine 6-O-demethylase (T6ODM) and codeine-3-O-demethylase (CODM), are involved in the morphine biosynthesis pathway from thebaine, catalyzing the O-demethylation reaction with precise regioselectivity at C6 and C3 positions of thebaine respectively. We investigated the origin of the regioselectivity of these enzymes by combined molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) calculations and found that Thebaine binds at the two distinct sites of T6ODM and CODM, which determines the regioselectivity of the enzymes. A remarkable oxo rotation is observed in the decarboxylation process. Starting from the closed pentacoordinate configuration, the C-terminal lid adopts an open conformation in the octahedral Fe(IV) = O complex to facilitate the subsequent demethylation. Phe241 and Phe311 stabilize the substrate in the binding pocket, while Arg219 acts as a gatekeeper residue to stabilize the substrate. Our results unravel the regioselectivity in 2-OG dependent nonheme enzymes and may shed light for exploring the substrate scope of these enzymes and developing novel biotechnology for morphine biosynthesis.
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Affiliation(s)
- Warispreet Singh
- Department of Chemistry & Chemical Engineering, Queen's University, Belfast BT9 5AG, United Kingdom
| | - Chenggong Hui
- Department of Chemistry & Chemical Engineering, Queen's University, Belfast BT9 5AG, United Kingdom
| | - Chun Li
- Key Lab of Industrial Biocatalysis Ministry of Education, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Meilan Huang
- Department of Chemistry & Chemical Engineering, Queen's University, Belfast BT9 5AG, United Kingdom
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15
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Functional role of residues involved in substrate binding of human 4-hydroxyphenylpyruvate dioxygenase. Biochem J 2021; 478:2201-2215. [PMID: 34047349 DOI: 10.1042/bcj20210005] [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: 01/11/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 11/17/2022]
Abstract
4-Hydroxylphenylpyruvate dioxygenase (HPPD) catalyzes the conversion of 4-hydroxylphenylpyruvate (HPP) to homogentisate, the important step for tyrosine catabolism. Comparison of the structure of human HPPD with the substrate-bound structure of A. thaliana HPPD revealed notably different orientations of the C-terminal helix. This helix performed as a closed conformation in human enzyme. Simulation revealed a different substrate-binding mode in which the carboxyl group of HPP interacted by a H-bond network formed by Gln334, Glu349 (the metal-binding ligand), and Asn363 (in the C-terminal helix). The 4-hydroxyl group of HPP interacted with Gln251 and Gln265. The relative activity and substrate-binding affinity were preserved for the Q334A mutant, implying the alternative role of Asn363 for HPP binding and catalysis. The reduction in kcat/Km of the Asn363 mutants confirmed the critical role in catalysis. Compared to the N363A mutant, the dramatic reduction in the Kd and thermal stability of the N363D mutant implies the side-chain effect in the hinge region rotation of the C-terminal helix. The activity and binding affinity were not recovered by double mutation; however, the 4-hydroxyphenylacetate intermediate formation by the uncoupled reaction of Q334N/N363Q and Q334A/N363D mutants indicated the importance of the H-bond network in the electrophilic reaction. These results highlight the functional role of the H-bond network in a closed conformation of the C-terminal helix to stabilize the bound substrate. The extremely low activity and reduction in Q251E's Kd suggest that interaction coupled with the H-bond network is crucial to locate the substrate for nucleophilic reaction.
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16
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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: 20] [Impact Index Per Article: 6.7] [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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17
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Ali HS, Henchman RH, Visser SP. Mechanism of Oxidative Ring‐Closure as Part of the Hygromycin Biosynthesis Step by a Nonheme Iron Dioxygenase. ChemCatChem 2021. [DOI: 10.1002/cctc.202100393] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hafiz Saqib Ali
- Manchester Institute of Biotechnology The University of Manchester 131 Princess Street Manchester M1 7DN UK
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Richard H. Henchman
- Manchester Institute of Biotechnology The University of Manchester 131 Princess Street Manchester M1 7DN UK
- Department of Chemistry The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Sam P. 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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18
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Han SB, Ali HS, de Visser SP. Glutarate Hydroxylation by the Carbon Starvation-Induced Protein D: A Computational Study into the Stereo- and Regioselectivities of the Reaction. Inorg Chem 2021; 60:4800-4815. [DOI: 10.1021/acs.inorgchem.0c03749] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Sungho Bosco Han
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
- Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Hafiz Saqib Ali
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
- Department of Chemistry, 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 and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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19
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Waheed SO, Chaturvedi SS, Karabencheva-Christova TG, Christov CZ. Catalytic Mechanism of Human Ten-Eleven Translocation-2 (TET2) Enzyme: Effects of Conformational Changes, Electric Field, and Mutations. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05034] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sodiq O. Waheed
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Shobhit S. Chaturvedi
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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20
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Chaturvedi SS, Ramanan R, Hu J, Hausinger RP, Christov CZ. Atomic and Electronic Structure Determinants Distinguish between Ethylene Formation and l-Arginine Hydroxylation Reaction Mechanisms in the Ethylene-Forming Enzyme. ACS Catal 2021. [DOI: 10.1021/acscatal.0c03349] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Shobhit S. Chaturvedi
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | | | | | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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21
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Wang C, Wu P, Wang Z, Wang B. The molecular mechanism of P450-catalyzed amination of the pyrrolidine derivative of lidocaine: insights from multiscale simulations. RSC Adv 2021; 11:27674-27680. [PMID: 35480638 PMCID: PMC9037892 DOI: 10.1039/d1ra04564d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/09/2021] [Indexed: 11/23/2022] Open
Abstract
Nitrogen heterocycles are key and prevalent motifs in drugs. Evolved variants of cytochrome P450BM3 (CYP102A1) from Bacillus megaterium employ high-valent oxo-iron(iv) species to catalyze the synthesis of imidazolidine-4-ones via an intramolecular C–H amination. Herein, we use multi-scale simulations, including classical molecular dynamics (MD) simulations, quantum mechanical/molecular mechanical (QM/MM) calculations and QM calculations, to reveal the molecular mechanism of the intramolecular C–H amination of the pyrrolidine derivative of lidocaine bearing cyclic amino moieties catalyzed by the variant RP/FV/EV of P450BM3, which bears five mutations compared to wild type. Our calculations show that overall catalysis includes both the enzymatic transformation in P450 and non-enzymatic transformation in water solution. The enzymatic transformation involves the exclusive hydroxylation of the C–H bond of the pyrrolidine derivative of lidocaine, leading to the hydroxylated intermediate, during which the substrate radical would be bypassed. The following dehydration and C–N coupling reactions are found to be much favored in aqueous situation compared to that in the non-polar protein environment. The present findings expand our understanding of the P450-catalyzed C(sp3)–H amination reaction. Nitrogen heterocycles are key and prevalent motifs in drugs.![]()
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Affiliation(s)
- Conger Wang
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Peng Wu
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Zhanfeng Wang
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
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22
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Ali HS, Henchman RH, de Visser SP. What Determines the Selectivity of Arginine Dihydroxylation by the Nonheme Iron Enzyme OrfP? Chemistry 2020; 27:1795-1809. [PMID: 32965733 DOI: 10.1002/chem.202004019] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/22/2020] [Indexed: 12/13/2022]
Abstract
The nonheme iron enzyme OrfP reacts with l-Arg selectively to form the 3R,4R-dihydroxyarginine product, which in mammals can inhibit the nitric oxide synthase enzymes involved in blood pressure control. To understand the mechanisms of dioxygen activation of l-Arg by OrfP and how it enables two sequential oxidation cycles on the same substrate, we performed a density functional theory study on a large active site cluster model. We show that substrate binding and positioning in the active site guides a highly selective reaction through C3 -H hydrogen atom abstraction. This happens despite the fact that the C3 -H and C4 -H bond strengths of l-Arg are very similar. Electronic differences in the two hydrogen atom abstraction pathways drive the reaction with an initial C3 -H activation to a low-energy 5 σ-pathway, while substrate positioning destabilizes the C4 -H abstraction and sends it over the higher-lying 5 π-pathway. We show that substrate and monohydroxylated products are strongly bound in the substrate binding pocket and hence product release is difficult and consequently its lifetime will be long enough to trigger a second oxygenation cycle.
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Affiliation(s)
- Hafiz Saqib Ali
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Richard H Henchman
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,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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23
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Wojdyla Z, Borowski T. Enzyme Multifunctionality by Control of Substrate Positioning Within the Catalytic Cycle—A QM/MM Study of Clavaminic Acid Synthase. Chemistry 2020; 27:2196-2211. [DOI: 10.1002/chem.202004426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Zuzanna Wojdyla
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences Niezapominajek 8 30239 Krakow Poland
| | - Tomasz Borowski
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences Niezapominajek 8 30239 Krakow Poland
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24
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Ramanan R, Chaturvedi SS, Lehnert N, Schofield CJ, Karabencheva-Christova TG, Christov CZ. Catalysis by the JmjC histone demethylase KDM4A integrates substrate dynamics, correlated motions and molecular orbital control. Chem Sci 2020; 11:9950-9961. [PMID: 34094257 PMCID: PMC8162366 DOI: 10.1039/d0sc03713c] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Nε-methyl lysine status of histones is important in the regulation of eukaryotic transcription. The Fe(ii) and 2-oxoglutarate (2OG) -dependent JmjC domain enzymes are the largest family of histone Nε-methyl lysine demethylases (KDMs). The human KDM4 subfamily of JmjC KDMs is linked with multiple cancers and some of its members are medicinal chemistry targets. We describe the use of combined molecular dynamics (MD) and Quantum Mechanical/Molecular Mechanical (QM/MM) methods to study the mechanism of KDM4A, which catalyzes demethylation of both tri- and di-methylated forms of histone H3 at K9 and K36. The results show that the oxygen activation at the active site of KDM4A is optimized towards the generation of the reactive Fe(iv)-oxo intermediate. Factors including the substrate binding mode, correlated motions of the protein and histone substrates, and molecular orbital control synergistically contribute to the reactivity of the Fe(iv)-oxo intermediate. In silico substitutions were performed to investigate the roles of residues (Lys241, Tyr177, and Asn290) in substrate orientation. The Lys241Ala substitution abolishes activity due to altered substrate orientation consistent with reported experimental studies. Calculations with a macrocyclic peptide substrate analogue reveal that induced conformational changes/correlated motions in KDM4A are sequence-specific in a manner that influences substrate binding affinity. Second sphere residues, such as Ser288 and Thr289, may contribute to KDM4A catalysis by correlated motions with active site residues. Residues that stabilize key intermediates, and which are predicted to be involved in correlated motions with other residues in the second sphere and beyond, are shown to be different in KDM4A compared to those in another JmjC KDM (PHF8), which acts on H3K9 di- and mono-methylated forms, suggesting that allosteric type inhibition is of interest from the perspective of developing selective JmjC KDM inhibitors. The second sphere residues and regions of the protein in histone demethylase enzymes that makes correlated motion with the active site contribute to efficient catalysis.![]()
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Affiliation(s)
- Rajeev Ramanan
- Department of Chemistry, Michigan Technological University Houghton Michigan 49931 USA
| | - Shobhit S Chaturvedi
- Department of Chemistry, Michigan Technological University Houghton Michigan 49931 USA
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan Ann Arbor MI 48019 USA
| | | | | | - Christo Z Christov
- Department of Chemistry, Michigan Technological University Houghton Michigan 49931 USA
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25
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Waheed S, Ramanan R, Chaturvedi SS, Lehnert N, Schofield CJ, Christov CZ, Karabencheva-Christova TG. Role of Structural Dynamics in Selectivity and Mechanism of Non-heme Fe(II) and 2-Oxoglutarate-Dependent Oxygenases Involved in DNA Repair. ACS CENTRAL SCIENCE 2020; 6:795-814. [PMID: 32490196 PMCID: PMC7256942 DOI: 10.1021/acscentsci.0c00312] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Indexed: 05/08/2023]
Abstract
AlkB and its human homologue AlkBH2 are Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases that repair alkylated DNA bases occurring as a consequence of reactions with mutagenic agents. We used molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) methods to investigate how structural dynamics influences the selectivity and mechanisms of the AlkB- and AlkBH2-catalyzed demethylation of 3-methylcytosine (m3C) in single (ssDNA) and double (dsDNA) stranded DNA. Dynamics studies reveal the importance of the flexibility in both the protein and DNA components in determining the preferences of AlkB for ssDNA and of AlkBH2 for dsDNA. Correlated motions, including of a hydrophobic β-hairpin, are involved in substrate binding in AlkBH2-dsDNA. The calculations reveal that 2OG rearrangement prior to binding of dioxygen to the active site Fe is preferred over a ferryl rearrangement to form a catalytically productive Fe(IV)=O intermediate. Hydrogen atom transfer proceeds via a σ-channel in AlkBH2-dsDNA and AlkB-dsDNA; in AlkB-ssDNA, there is a competition between σ- and π-channels, implying that the nature of the complexed DNA has potential to alter molecular orbital interactions during the substrate oxidation. Our results reveal the importance of the overall protein-DNA complex in determining selectivity and how the nature of the substrate impacts the mechanism.
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Affiliation(s)
- Sodiq
O. Waheed
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Shobhit S. Chaturvedi
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Nicolai Lehnert
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Christopher J. Schofield
- The
Chemistry Research Laboratory, The Department of Chemistry, Mansfield
Road, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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26
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Li J, Liao HJ, Tang Y, Huang JL, Cha L, Lin TS, Lee JL, Kurnikov IV, Kurnikova MG, Chang WC, Chan NL, Guo Y. Epoxidation Catalyzed by the Nonheme Iron(II)- and 2-Oxoglutarate-Dependent Oxygenase, AsqJ: Mechanistic Elucidation of Oxygen Atom Transfer by a Ferryl Intermediate. J Am Chem Soc 2020; 142:6268-6284. [PMID: 32131594 PMCID: PMC7343540 DOI: 10.1021/jacs.0c00484] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mechanisms of enzymatic epoxidation via oxygen atom transfer (OAT) to an olefin moiety is mainly derived from the studies on thiolate-heme containing epoxidases, such as cytochrome P450 epoxidases. The molecular basis of epoxidation catalyzed by nonheme-iron enzymes is much less explored. Herein, we present a detailed study on epoxidation catalyzed by the nonheme iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenase, AsqJ. The native substrate and analogues with different para substituents ranging from electron-donating groups (e.g., methoxy) to electron-withdrawing groups (e.g., trifluoromethyl) were used to probe the mechanism. The results derived from transient-state enzyme kinetics, Mössbauer spectroscopy, reaction product analysis, X-ray crystallography, density functional theory calculations, and molecular dynamic simulations collectively revealed the following mechanistic insights: (1) The rapid O2 addition to the AsqJ Fe(II) center occurs with the iron-bound 2OG adopting an online-binding mode in which the C1 carboxylate group of 2OG is trans to the proximal histidine (His134) of the 2-His-1-carboxylate facial triad, instead of assuming the offline-binding mode with the C1 carboxylate group trans to the distal histidine (His211); (2) The decay rate constant of the ferryl intermediate is not strongly affected by the nature of the para substituents of the substrate during the OAT step, a reactivity behavior that is drastically different from nonheme Fe(IV)-oxo synthetic model complexes; (3) The OAT step most likely proceeds through a stepwise process with the initial formation of a C(benzylic)-O bond to generate an Fe-alkoxide species, which is observed in the AsqJ crystal structure. The subsequent C3-O bond formation completes the epoxide installation.
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Affiliation(s)
- Jikun Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yijie Tang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jhih-Liang Huang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Lide Cha
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Te-Sheng Lin
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Justin L. Lee
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Igor V. Kurnikov
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Maria G. Kurnikova
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Wei-chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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27
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Chaturvedi S, Ramanan R, Lehnert N, Schofield CJ, Karabencheva-Christova TG, Christov CZ. Catalysis by the Non-Heme Iron(II) Histone Demethylase PHF8 Involves Iron Center Rearrangement and Conformational Modulation of Substrate Orientation. ACS Catal 2020; 10:1195-1209. [PMID: 31976154 PMCID: PMC6970271 DOI: 10.1021/acscatal.9b04907] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/10/2019] [Indexed: 02/07/2023]
Abstract
PHF8 (KDM7B) is a human non-heme 2-oxoglutarate (2OG) JmjC domain oxygenase that catalyzes the demethylation of the di/mono-Nε-methylated K9 residue of histone H3. Altered PHF8 activity is linked to genetic diseases and cancer; thus, it is an interesting target for epigenetic modulation. We describe the use of combined quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) simulations to explore the mechanism of PHF8, including dioxygen activation, 2OG binding modes, and substrate demethylation steps. A PHF8 crystal structure manifests the 2OG C-1 carboxylate bound to iron in a nonproductive orientation, i.e., trans to His247. A ferryl-oxo intermediate formed by activating dioxygen bound to the vacant site in this complex would be nonproductive, i.e., "off-line" with respect to reaction with Nε-methylated K9. We show rearrangement of the "off-line" ferryl-oxo intermediate to a productive "in-line" geometry via a solvent exchange reaction (called "ferryl-flip") is energetically unfavorable. The calculations imply that movement of the 2OG C-1 carboxylate prior to dioxygen binding at a five-coordination stage in catalysis proceeds with a low barrier, suggesting that two possible 2OG C-1 carboxylate geometries can coexist at room temperature. We explored alternative mechanisms for hydrogen atom transfer and show that second sphere interactions orient the Nε-methylated lysine in a conformation where hydrogen abstraction from a methyl C-H bond is energetically more favorable than hydrogen abstraction from the N-H bond of the protonated Nε-methyl group. Using multiple HAT reaction path calculations, we demonstrate the crucial role of conformational flexibility in effective hydrogen transfer. Subsequent hydroxylation occurs through a rebound mechanism, which is energetically preferred compared to desaturation, due to second sphere interactions. The overall mechanistic insights reveal the crucial role of iron-center rearrangement, second sphere interactions, and conformational flexibility in PHF8 catalysis and provide knowledge useful for the design of mechanism-based PHF8 inhibitors.
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Affiliation(s)
- Shobhit
S. Chaturvedi
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Nicolai Lehnert
- Department
of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | | | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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28
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Yuan C, Zhang Y, Tan H, Li X, Chen G, Jia Z. ONIOM investigations of the heme degradation mechanism by MhuD: the critical function of heme ruffling. Phys Chem Chem Phys 2020; 22:8817-8826. [DOI: 10.1039/c9cp05868k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A unique ruffling conformation of hydroxyheme in MhuD inhibits its “on-site” monooxygenation but induces “remote-site” dioxygenation.
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Affiliation(s)
- Chang Yuan
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Ying Zhang
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Hongwei Tan
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Xichen Li
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Guangju Chen
- College of Chemistry
- Key Laboratories of Theoretical and Computational Photochemistry
- Ministry of Education
- Beijing Normal University
- Beijing
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences
- Queen's University
- Kingston
- Ontario
- Canada
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29
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Ghafoor S, Mansha A, de Visser SP. Selective Hydrogen Atom Abstraction from Dihydroflavonol by a Nonheme Iron Center Is the Key Step in the Enzymatic Flavonol Synthesis and Avoids Byproducts. J Am Chem Soc 2019; 141:20278-20292. [PMID: 31749356 DOI: 10.1021/jacs.9b10526] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The plant non-heme iron dioxygenase flavonol synthase performs a regioselective desaturation reaction as part of the biosynthesis of the signaling molecule flavonol that triggers the growing of leaves and flowers. These compounds also have health benefits for humans. Desaturation of aliphatic compounds generally proceeds through two consecutive hydrogen atom abstraction steps from two adjacent carbon atoms and in nature often is performed by a high-valent iron(IV)-oxo species. We show that the order of the hydrogen atom abstraction steps, however, is opposite of those expected from the C-H bond strengths in the substrate and determines the product distributions. As such, flavonol synthase follows a negative catalysis mechanism. Using density functional theory methods on large active-site model complexes, we investigated pathways for desaturation and hydroxylation by an iron(IV)-oxo active-site model. Contrary to thermochemical predictions, we find that the oxidant abstracts the hydrogen atom from the strong C2-H bond rather than the weaker C3-H bond of the substrate first. We analyze the origin of this unexpected selective hydrogen atom abstraction pathway and find that the alternative C3-H hydrogen atom abstraction would be followed by a low-energy and competitive substrate hydroxylation mechanism hence, should give considerable amount of byproducts. Our computational modeling studies show that substrate positioning in flavonol synthase is essential, as it guides the reactivity to a chemo- and regioselective substrate desaturation from the C2-H group, leading to desaturation products efficiently.
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Affiliation(s)
- Sidra Ghafoor
- The Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science , The University of Manchester , 131 Princess Street , Manchester M1 7DN , United Kingdom.,Department of Chemistry , Government College University Faisalabad , New Campus, Jhang Road , Faisalabad 38000 , Pakistan
| | - Asim Mansha
- Department of Chemistry , Government College University Faisalabad , New Campus, Jhang Road , Faisalabad 38000 , Pakistan
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science , The University of Manchester , 131 Princess Street , Manchester M1 7DN , United Kingdom
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30
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Lin Y, Stańczak A, Manchev Y, Straganz GD, Visser SP. Can a Mononuclear Iron(III)‐Superoxo Active Site Catalyze the Decarboxylation of Dodecanoic Acid in UndA to Produce Biofuels? Chemistry 2019; 26:2233-2242. [DOI: 10.1002/chem.201903783] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/24/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Yen‐Ting Lin
- The Manchester Institute of Biotechnology and Department of, Chemical Engineering and Analytical ScienceThe University of, Manchester 131 Princess Street Manchester M1 7DN UK
| | - Agnieszka Stańczak
- The Manchester Institute of Biotechnology and Department of, Chemical Engineering and Analytical ScienceThe University of, Manchester 131 Princess Street Manchester M1 7DN UK
- Faculty of ChemistrySilesian University of Technology ks. Marcina Strzody 9 44-100 Gliwice Poland
- Tunneling Group, Biotechnology CentreSilesian University of Technology ul. Krzywoustego 8 44–100 Gliwice Poland
| | - Yulian Manchev
- The Manchester Institute of Biotechnology and Department of, Chemical Engineering and Analytical ScienceThe University of, Manchester 131 Princess Street Manchester M1 7DN UK
| | - Grit D. Straganz
- Graz University of TechnologyInstitute of Biochemistry Petergasse 12 8010 Graz Austria
| | - Sam P. Visser
- The Manchester Institute of Biotechnology and Department of, Chemical Engineering and Analytical ScienceThe University of, Manchester 131 Princess Street Manchester M1 7DN UK
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31
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Pan J, Wenger ES, Matthews ML, Pollock CJ, Bhardwaj M, Kim AJ, Allen BD, Grossman RB, Krebs C, Bollinger JM. Evidence for Modulation of Oxygen Rebound Rate in Control of Outcome by Iron(II)- and 2-Oxoglutarate-Dependent Oxygenases. J Am Chem Soc 2019; 141:15153-15165. [PMID: 31475820 DOI: 10.1021/jacs.9b06689] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases generate iron(IV)-oxo (ferryl) intermediates that can abstract hydrogen from aliphatic carbons (R-H). Hydroxylation proceeds by coupling of the resultant substrate radical (R•) and oxygen of the Fe(III)-OH complex ("oxygen rebound"). Nonhydroxylation outcomes result from different fates of the Fe(III)-OH/R• state; for example, halogenation results from R• coupling to a halogen ligand cis to the hydroxide. We previously suggested that halogenases control substrate-cofactor disposition to disfavor oxygen rebound and permit halogen coupling to prevail. Here, we explored the general implication that, when a ferryl intermediate can ambiguously target two substrate carbons for different outcomes, rebound to the site capable of the alternative outcome should be slower than to the adjacent, solely hydroxylated site. We evaluated this prediction for (i) the halogenase SyrB2, which exclusively hydroxylates C5 of norvaline appended to its carrier protein but can either chlorinate or hydroxylate C4 and (ii) two bifunctional enzymes that normally hydroxylate one carbon before coupling that oxygen to a second carbon (producing an oxacycle) but can, upon encountering deuterium at the first site, hydroxylate the second site instead. In all three cases, substrate hydroxylation incorporates a greater fraction of solvent-derived oxygen at the site that can also undergo the alternative outcome than at the other site, most likely reflecting an increased exchange of the initially O2-derived oxygen ligand in the longer-lived Fe(III)-OH/R• states. Suppression of rebound may thus be generally important for nonhydroxylation outcomes by these enzymes.
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Affiliation(s)
| | | | | | | | - Minakshi Bhardwaj
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40546-0312 , United States
| | | | | | - Robert B Grossman
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40546-0312 , United States
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32
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Xue J, Lu J, Lai W. Mechanistic insights into a non-heme 2-oxoglutarate-dependent ethylene-forming enzyme: selectivity of ethylene-formation versusl-Arg hydroxylation. Phys Chem Chem Phys 2019; 21:9957-9968. [PMID: 31041955 DOI: 10.1039/c9cp00794f] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ethylene-forming enzyme (EFE) is a unique member of the Fe(ii)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases. It converts 2OG into ethylene plus three CO2 molecules (ethylene-forming reaction) and also catalyzes the C5 hydroxylation of l-arginine coupled to the oxidative decarboxylation of 2OG (l-Arg hydroxylation reaction). To uncover the mechanisms of the dual transformations by EFE, quantum mechanical/molecular mechanical (QM/MM) calculations were carried out. Based on the results, a branched mechanism was proposed. An FeII-peroxysuccinate complex with a dissociated CO2 generated through the nucleophilic attack of the superoxo moiety of the Fe-O2 species on the keto carbon of 2OG is the key common intermediate in both reactions. A competition between the subsequent CO2 insertion (a key step in the ethylene-forming pathway) and the O-O bond cleavage (leading to the formation of succinate) governs the product selectivity. The calculated reaction barriers suggested that the CO2 insertion is favored over the O-O bond cleavage. This is consistent with the product preference observed in experiments. By comparison with the results of AsqJ (an Fe/2OG oxygenase that leads to substrate oxidation exclusively), the protein environment was found to be crucial for the selectivity. Further calculations demonstrated that the local electric field of the protein environment in EFE promotes ethylene formation by acting as a charge template, exemplifying the importance of the electrostatic interaction in enzyme catalysis. These findings offer mechanistic insights into the EFE catalysis and provide important clues for better understanding the unique ethylene-forming capability of EFE compared with other Fe/2OG oxygenases.
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Affiliation(s)
- Junqin Xue
- Department of Chemistry, Renmin University of China, Beijing, 100872, China.
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33
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Lu J, Lai W. Mechanistic Insights into a Stibene Cleavage Oxygenase NOV1 from Quantum Mechanical/Molecular Mechanical Calculations. ChemistryOpen 2019; 8:228-235. [PMID: 30828510 PMCID: PMC6382310 DOI: 10.1002/open.201800259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/30/2019] [Indexed: 12/03/2022] Open
Abstract
NOV1, a stilbene cleavage oxygenase, catalyzes the cleavage of the central double bond of stilbenes to two phenolic aldehydes, using a 4-His Fe(II) center and dioxygen. Herein, we use in-protein quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the reaction mechanism of the central double bond cleavage of phytoalexin resveratrol by NOV1. Our results showed that the oxygen molecule prefers to bind to the iron center in a side-on fashion, as suggested from the experiment. The quintet Fe-O2 complex with the side-on superoxo antiferromagnetic coupled to the resveratrol radical is identified as the reactive oxygen species. The QM/MM results support the dioxygenase mechanism involving a dioxetane intermediate with a rate-limiting barrier of 10.0 kcal mol-1. The alternative pathway through an epoxide intermediate is ruled out due to a larger rate-limiting barrier (26.8 kcal mol-1). These findings provide important insight into the catalytic mechanism of carotenoid cleavage oxygenases and also the dioxygen activation of non-heme enzymes.
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Affiliation(s)
- Jiarui Lu
- Department of ChemistryRenmin University of ChinaNo. 59 Zhongguancun Street, Haidian DistrictBeijing100872P. R. China
| | - Wenzhen Lai
- Department of ChemistryRenmin University of ChinaNo. 59 Zhongguancun Street, Haidian DistrictBeijing100872P. R. China
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34
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Li S, Lu J, Lai W. Mechanistic insights into ring cleavage of hydroquinone by PnpCD from quantum mechanical/molecular mechanical calculations. Org Biomol Chem 2019; 17:8194-8205. [DOI: 10.1039/c9ob01084j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
QM/MM calculations for ring cleavage of hydroquinone by PnpCD show that Asn258 loses coordination to the iron when the reaction begins. The first-sphere Glu262 can act as an acid–base catalyst to lower the rate-limiting barrier.
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Affiliation(s)
- Senzhi Li
- Department of Chemistry
- Renmin University of China
- Beijing
- China
| | - Jiarui Lu
- Department of Chemistry
- Renmin University of China
- Beijing
- China
| | - Wenzhen Lai
- Department of Chemistry
- Renmin University of China
- Beijing
- China
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35
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Ushimaru R, Ruszczycky MW, Liu HW. Changes in Regioselectivity of H Atom Abstraction during the Hydroxylation and Cyclization Reactions Catalyzed by Hyoscyamine 6β-Hydroxylase. J Am Chem Soc 2018; 141:1062-1066. [PMID: 30545219 DOI: 10.1021/jacs.8b11585] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Hyoscyamine 6β-hydroxylase (H6H) is an αKG-dependent nonheme iron oxidase that catalyzes the oxidation of hyoscyamine to scopolamine via two separate reactions: hydroxylation followed by oxidative cyclization. Both of these reactions are expected to involve H atom abstraction from each of two adjacent carbon centers (C6 vs C7) in the substrate. During hydroxylation, there is a roughly 85:1 preference for H atom abstraction from C6 versus C7; however, this inverts to a 1:16 preference during cyclization. Furthermore, 18O incorporation experiments in the presence of deuterated substrate are consistent with the catalytic iron(IV)-oxo complex being able to support the coordination of an additional ligand during hydroxylation. These observations suggest that subtle differences in the substrate binding configuration can have significant consequences for the catalytic cycle of H6H.
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Affiliation(s)
- Richiro Ushimaru
- Department of Chemistry , University of Texas at Austin , Austin , TX 78712 , United States
| | - Mark W Ruszczycky
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy , University of Texas at Austin , Austin , TX 78712 , United States
| | - Hung-Wen Liu
- Department of Chemistry , University of Texas at Austin , Austin , TX 78712 , United States.,Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy , University of Texas at Austin , Austin , TX 78712 , United States
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36
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Chang WC, Liu P, Guo Y. Mechanistic Elucidation of Two Catalytically Versatile Iron(II)- and α-Ketoglutarate-Dependent Enzymes: Cases Beyond Hydroxylation. COMMENT INORG CHEM 2018. [DOI: 10.1080/02603594.2018.1509856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Wei-chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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37
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Enzymatic one-step ring contraction for quinolone biosynthesis. Nat Commun 2018; 9:2826. [PMID: 30026518 PMCID: PMC6053404 DOI: 10.1038/s41467-018-05221-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/29/2018] [Indexed: 12/25/2022] Open
Abstract
The 6,6-quinolone scaffolds on which viridicatin-type fungal alkaloids are built are frequently found in metabolites that display useful biological activities. Here we report in vitro and computational analyses leading to the discovery of a hemocyanin-like protein AsqI from the Aspergillus nidulans aspoquinolone biosynthetic pathway that forms viridicatins via a conversion of the cyclopenin-type 6,7-bicyclic system into the viridicatin-type 6,6-bicyclic core through elimination of carbon dioxide and methylamine through methyl isocyanate. Viridicatin is a fungal alkaloid. Here, the authors identify and characterize the cyclopenase that catalyzes the last step of its biosynthesis in Aspergillus nidulans, the conversion of cyclopenin to viridicatin, and find that the reaction proceeds via an unusual elimination mechanism.
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38
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Nakashima Y, Mitsuhashi T, Matsuda Y, Senda M, Sato H, Yamazaki M, Uchiyama M, Senda T, Abe I. Structural and Computational Bases for Dramatic Skeletal Rearrangement in Anditomin Biosynthesis. J Am Chem Soc 2018; 140:9743-9750. [DOI: 10.1021/jacs.8b06084] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yu Nakashima
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takaaki Mitsuhashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yudai Matsuda
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Miki Senda
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Hajime Sato
- Graduate School of Pharmaceutical Science, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
- Cluster of Pioneering Research (CPR), Advanced Elements Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mami Yamazaki
- Graduate School of Pharmaceutical Science, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Cluster of Pioneering Research (CPR), Advanced Elements Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Department of Materials Structure Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (Soken-dai), 1−1 Oho, Tsukuba, Ibaraki 305−0801, Japan
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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39
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On how the binding cavity of AsqJ dioxygenase controls the desaturation reaction regioselectivity: a QM/MM study. J Biol Inorg Chem 2018; 23:795-808. [PMID: 29876666 PMCID: PMC6015105 DOI: 10.1007/s00775-018-1575-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/23/2018] [Indexed: 02/03/2023]
Abstract
The Fe(II)/2-oxoglutarate-dependent dioxygenase AsqJ from Aspergillus nidulans catalyses two pivotal steps in the synthesis of quinolone antibiotic 4'-methoxyviridicatin, i.e., desaturation and epoxidation of a benzodiazepinedione. The previous experimental results signal that, during the desaturation reaction, hydrogen atom transfer (HAT) from the benzylic carbon atom (C10) is a more likely step to initiate the reaction than the alternative HAT from the ring moiety (C3 atom). To unravel the origins of this regioselectivity and to explain why the observed reaction is desaturation and not the "default" hydroxylation, we performed a QM/MM study on the reaction catalysed by AsqJ. Herein, we report results that complement the experimental findings and suggest that HAT at the C10 position is the preferred reaction due to favourable interactions between the substrate and the binding cavity that compensate for the relatively high intrinsic barrier associated with the process. For the resultant radical intermediate, the desaturation/hydroxylation selectivity is governed by electronic properties of the reactants, i.e., the energy gap between the orbital that hosts the unpaired electron and the sigma orbital for the C-H bond as well as the gap between the orbitals mixing in transition state structures for each elementary step. Regiospecificity of the AsqJ dehydrogenation reaction is dictated by substrate-protein interactions. 82 × 44 mm (300 × 300 dpi).
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40
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Herr CQ, Hausinger RP. Amazing Diversity in Biochemical Roles of Fe(II)/2-Oxoglutarate Oxygenases. Trends Biochem Sci 2018; 43:517-532. [PMID: 29709390 DOI: 10.1016/j.tibs.2018.04.002] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/21/2018] [Accepted: 04/01/2018] [Indexed: 12/13/2022]
Abstract
Since their discovery in the 1960s, the family of Fe(II)/2-oxoglutarate-dependent oxygenases has undergone a tremendous expansion to include enzymes catalyzing a vast diversity of biologically important reactions. Recent examples highlight roles in controlling chromatin modification, transcription, mRNA demethylation, and mRNA splicing. Others generate modifications in tRNA, translation factors, ribosomes, and other proteins. Thus, oxygenases affect all components of molecular biology's central dogma, in which information flows from DNA to RNA to proteins. These enzymes also function in biosynthesis and catabolism of cellular metabolites, including antibiotics and signaling molecules. Due to their critical importance, ongoing efforts have targeted family members for the development of specific therapeutics. This review provides a general overview of recently characterized oxygenase reactions and their key biological roles.
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Affiliation(s)
- Caitlyn Q Herr
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
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41
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Catalytic mechanism and molecular engineering of quinolone biosynthesis in dioxygenase AsqJ. Nat Commun 2018; 9:1168. [PMID: 29563492 PMCID: PMC5862883 DOI: 10.1038/s41467-018-03442-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 02/13/2018] [Indexed: 12/02/2022] Open
Abstract
The recently discovered FeII/α-ketoglutarate-dependent dioxygenase AsqJ from Aspergillus nidulans stereoselectively catalyzes a multistep synthesis of quinolone alkaloids, natural products with significant biomedical applications. To probe molecular mechanisms of this elusive catalytic process, we combine here multi-scale quantum and classical molecular simulations with X-ray crystallography, and in vitro biochemical activity studies. We discover that methylation of the substrate is essential for the activity of AsqJ, establishing molecular strain that fine-tunes π-stacking interactions within the active site. To rationally engineer AsqJ for modified substrates, we amplify dispersive interactions within the active site. We demonstrate that the engineered enzyme has a drastically enhanced catalytic activity for non-methylated surrogates, confirming our computational data and resolved high-resolution X-ray structures at 1.55 Å resolution. Our combined findings provide crucial mechanistic understanding of the function of AsqJ and showcase how combination of computational and experimental data enables to rationally engineer enzymes. The catalytic activity of dioxygenase AsqJ is strictly relying on the methylation of quinolone substrates. Here, the authors apply molecular simulations, X-ray crystallography and in vitro biochemical studies to the engineering of dioxygenase AsqJ with improved catalytic activity for modified non-methylated surrogates.
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42
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Nakamura H, Matsuda Y, Abe I. Unique chemistry of non-heme iron enzymes in fungal biosynthetic pathways. Nat Prod Rep 2018. [DOI: 10.1039/c7np00055c] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions by non-heme iron enzymes in structurally intriguing fungal natural products pathways are summarized and discussed.
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Affiliation(s)
- Hitomi Nakamura
- Graduate School of Pharmaceutical Sciences
- The University of Tokyo
- Tokyo
- Japan
| | - Yudai Matsuda
- Graduate School of Pharmaceutical Sciences
- The University of Tokyo
- Tokyo
- Japan
- Department of Chemistry
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences
- The University of Tokyo
- Tokyo
- Japan
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Rugg G, Senn HM. Formation and structure of the ferryl [FeO] intermediate in the non-haem iron halogenase SyrB2: classical and QM/MM modelling agree. Phys Chem Chem Phys 2017; 19:30107-30119. [DOI: 10.1039/c7cp05937j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
All O2 activation roads for three substrates and three spin states in SyrB2 lead to the same [FeO] structure.
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Affiliation(s)
- G. Rugg
- WestCHEM and School of Chemistry
- University of Glasgow
- Glasgow G12 8QQ
- UK
| | - H. M. Senn
- WestCHEM and School of Chemistry
- University of Glasgow
- Glasgow G12 8QQ
- UK
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