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Papadopoulou A, Meyer F, Buller RM. Engineering Fe(II)/α-Ketoglutarate-Dependent Halogenases and Desaturases. Biochemistry 2023; 62:229-240. [PMID: 35446547 DOI: 10.1021/acs.biochem.2c00115] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Fe(II)/α-ketoglutarate-dependent dioxygenases (α-KGDs) are widespread enzymes in aerobic biology and serve a remarkable array of biological functions, including roles in collagen biosynthesis, plant and animal development, transcriptional regulation, nucleic acid modification, and secondary metabolite biosynthesis. This functional diversity is reflected in the enzymes' catalytic flexibility as α-KGDs can catalyze an intriguing set of synthetically valuable reactions, such as hydroxylations, halogenations, and desaturations, capturing the interest of scientists across disciplines. Mechanistically, all α-KGDs are understood to follow a similar activation pathway to generate a substrate radical, yet how individual members of the enzyme family direct this key intermediate toward the different reaction outcomes remains elusive, triggering structural, computational, spectroscopic, kinetic, and enzyme engineering studies. In this Perspective, we will highlight how first enzyme and substrate engineering examples suggest that the chemical reaction pathway within α-KGDs can be intentionally tailored using rational design principles. We will delineate the structural and mechanistic investigations of the reprogrammed enzymes and how they begin to inform about the enzymes' structure-function relationships that determine chemoselectivity. Application of this knowledge in future enzyme and substrate engineering campaigns will lead to the development of powerful C-H activation catalysts for chemical synthesis.
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Affiliation(s)
- Athena Papadopoulou
- Competence Center for Biocatalysis, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
| | - Fabian Meyer
- Competence Center for Biocatalysis, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
| | - Rebecca M Buller
- Competence Center for Biocatalysis, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
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2
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Gama SR, Stankovic T, Hupp K, Al Hejami A, McClean M, Evans A, Beauchemin D, Hammerschmidt F, Pallitsch K, Zechel DL. Biosynthesis of the Fungal Organophosphonate Fosfonochlorin Involves an Iron(II) and 2-(Oxo)glutarate Dependent Oxacyclase. Chembiochem 2021; 23:e202100352. [PMID: 34375042 DOI: 10.1002/cbic.202100352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/09/2021] [Indexed: 11/07/2022]
Abstract
The fungal metabolite Fosfonochlorin features a chloroacetyl moiety that is unusual within known phosphonate natural product biochemistry. Putative biosynthetic genes encoding Fosfonochlorin in Fusarium and Talaromyces spp. were investigated through reactions of encoded enzymes with synthetic substrates and isotope labelling studies. We show that early biosynthetic steps for Fosfonochlorin involves the reduction of phosphonoacetaldehyde to form 2-hydroxyethylphosphonic acid, followed by oxidative intramolecular cyclization of the resulting alcohol to form ( S )-epoxyethylphosphonic acid. The latter reaction is catalyzed by FfnD, a rare example of a non-heme iron / 2-(oxo)glutarate dependent oxacyclase. In contrast, FfnD behaves as a more typical oxygenase with ethylphosphonic acid, producing ( S )-1-hydroxyethylphosphonic acid. FfnD thus represents a new example of a ferryl generating enzyme that can suppress the typical oxygen rebound reaction that follows abstraction of a substrate hydrogen by a ferryl oxygen, thereby directing the substrate radical towards a fate other than hydroxylation.
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Affiliation(s)
- Simanga R Gama
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Toda Stankovic
- Institut für Organische Chemie, Universität Wien, 1090, Wien, Österreich
| | - Kendall Hupp
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Ahmed Al Hejami
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Mimi McClean
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Alysa Evans
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Diane Beauchemin
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | | | | | - David L Zechel
- Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
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3
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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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4
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Meyer F, Frey R, Ligibel M, Sager E, Schroer K, Snajdrova R, Buller R. Modulating Chemoselectivity in a Fe(II)/α-Ketoglutarate-Dependent Dioxygenase for the Oxidative Modification of a Nonproteinogenic Amino Acid. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00678] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Fabian Meyer
- Competence Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
| | - Raphael Frey
- Competence Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
| | - Mathieu Ligibel
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, 4056 Basel, Switzerland
| | - Emine Sager
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, 4056 Basel, Switzerland
| | - Kirsten Schroer
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, 4056 Basel, Switzerland
| | - Radka Snajdrova
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, 4056 Basel, Switzerland
| | - Rebecca Buller
- Competence Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland
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Dunham NP, Del Río Pantoja JM, Zhang B, Rajakovich LJ, Allen BD, Krebs C, Boal AK, Bollinger JM. Hydrogen Donation but not Abstraction by a Tyrosine (Y68) during Endoperoxide Installation by Verruculogen Synthase (FtmOx1). J Am Chem Soc 2019; 141:9964-9979. [PMID: 31117657 PMCID: PMC6901024 DOI: 10.1021/jacs.9b03567] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hydrogen-atom transfer (HAT) from a substrate carbon to an iron(IV)-oxo (ferryl) intermediate initiates a diverse array of enzymatic transformations. For outcomes other than hydroxylation, coupling of the resultant carbon radical and hydroxo ligand (oxygen rebound) must generally be averted. A recent study of FtmOx1, a fungal iron(II)- and 2-(oxo)glutarate-dependent oxygenase that installs the endoperoxide of verruculogen by adding O2 between carbons 21 and 27 of fumitremorgin B, posited that tyrosine (Tyr or Y) 224 serves as HAT intermediary to separate the C21 radical (C21•) and Fe(III)-OH HAT products and prevent rebound. Our reinvestigation of the FtmOx1 mechanism revealed, instead, direct HAT from C21 to the ferryl complex and surprisingly competitive rebound. The C21-hydroxylated (rebound) product, which undergoes deprenylation, predominates when low [O2] slows C21•-O2 coupling in the next step of the endoperoxidation pathway. This pathway culminates with addition of the C21-O-O• peroxyl adduct to olefinic C27 followed by HAT to the C26• from a Tyr. The last step results in sequential accumulation of Tyr radicals, which are suppressed without detriment to turnover by inclusion of the reductant, ascorbate. Replacement of each of four candidates for the proximal C26 H• donor (including Y224) with phenylalanine (F) revealed that only the Y68F variant (i) fails to accumulate the first Tyr• and (ii) makes an altered major product, identifying Y68 as the donor. The implied proximities of C21 to the iron cofactor and C26 to Y68 support a new docking model of the enzyme-substrate complex that is consistent with all available data.
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Affiliation(s)
- Noah P. Dunham
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Present Address: Division of Chemistry and Chemical
Engineering, California Institute of Technology, Pasadena, CA 91125
| | - José M. Del Río Pantoja
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Present Address: Department of Chemistry and Chemical
Biology, Harvard University, Cambridge, MA 02138
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
- Present Address: Renewable Energy Group, Inc., 600 Gateway
Blvd, South San Francisco, CA 94080
| | - Lauren J. Rajakovich
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Present Address: Department of Chemistry and Chemical
Biology, Harvard University, Cambridge, MA 02138
| | - Benjamin D. Allen
- The Huck Institutes for Life Sciences, The Pennsylvania
State University, University Park, PA 16802
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Amie K. Boal
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - J. Martin Bollinger
- Department of Biochemistry and Molecular Biology, The
Pennsylvania State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
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Dunham NP, Chang WC, Mitchell AJ, Martinie RJ, Zhang B, Bergman JA, Rajakovich LJ, Wang B, Silakov A, Krebs C, Boal AK, Bollinger JM. Two Distinct Mechanisms for C-C Desaturation by Iron(II)- and 2-(Oxo)glutarate-Dependent Oxygenases: Importance of α-Heteroatom Assistance. J Am Chem Soc 2018; 140:7116-7126. [PMID: 29708749 PMCID: PMC5999578 DOI: 10.1021/jacs.8b01933] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydroxylation of aliphatic carbons by nonheme Fe(IV)-oxo (ferryl) complexes proceeds by hydrogen-atom (H•) transfer (HAT) to the ferryl and subsequent coupling between the carbon radical and Fe(III)-coordinated oxygen (termed rebound). Enzymes that use H•-abstracting ferryl complexes for other transformations must either suppress rebound or further process hydroxylated intermediates. For olefin-installing C-C desaturations, it has been proposed that a second HAT to the Fe(III)-OH complex from the carbon α to the radical preempts rebound. Deuterium (2H) at the second site should slow this step, potentially making rebound competitive. Desaturations mediated by two related l-arginine-modifying iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases behave oppositely in this key test, implicating different mechanisms. NapI, the l-Arg 4,5-desaturase from the naphthyridinomycin biosynthetic pathway, abstracts H• first from C5 but hydroxylates this site (leading to guanidine release) to the same modest extent whether C4 harbors 1H or 2H. By contrast, an unexpected 3,4-desaturation of l-homoarginine (l-hArg) by VioC, the l-Arg 3-hydroxylase from the viomycin biosynthetic pathway, is markedly disfavored relative to C4 hydroxylation when C3 (the second hydrogen donor) harbors 2H. Anchimeric assistance by N6 permits removal of the C4-H as a proton in the NapI reaction, but, with no such assistance possible in the VioC desaturation, a second HAT step (from C3) is required. The close proximity (≤3.5 Å) of both l-hArg carbons to the oxygen ligand in an X-ray crystal structure of VioC harboring a vanadium-based ferryl mimic supports and rationalizes the sequential-HAT mechanism. The results suggest that, although the sequential-HAT mechanism is feasible, its geometric requirements may make competing hydroxylation unavoidable, thus explaining the presence of α-heteroatoms in nearly all native substrates for Fe/2OG desaturases.
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Affiliation(s)
- Noah P. Dunham
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Wei-chen Chang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Andrew J. Mitchell
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Ryan J. Martinie
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Jonathan A. Bergman
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Lauren J. Rajakovich
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Bo Wang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Alexey Silakov
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Amie K. Boal
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - J. Martin Bollinger
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
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7
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Martinie RJ, Pollock CJ, Matthews ML, Bollinger JM, Krebs C, Silakov A. Vanadyl as a Stable Structural Mimic of Reactive Ferryl Intermediates in Mononuclear Nonheme-Iron Enzymes. Inorg Chem 2017; 56:13382-13389. [PMID: 28960972 DOI: 10.1021/acs.inorgchem.7b02113] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases catalyze an array of challenging transformations via a common iron(IV)-oxo (ferryl) intermediate, which in most cases abstracts hydrogen (H•) from an aliphatic carbon of the substrate. Although it has been shown that the relative disposition of the Fe-O and C-H bonds can control the rate of H• abstraction and fate of the resultant substrate radical, there remains a paucity of structural information on the actual ferryl states, owing to their high reactivity. We demonstrate here that the stable vanadyl ion [(VIV-oxo)2+] binds along with 2OG or its decarboxylation product, succinate, in the active site of two different Fe/2OG enzymes to faithfully mimic their transient ferryl states. Both ferryl and vanadyl complexes of the Fe/2OG halogenase, SyrB2, remain stably bound to its carrier protein substrate (l-aminoacyl-S-SyrB1), whereas the corresponding complexes harboring transition metals (Fe, Mn) in lower oxidation states dissociate. In the well-studied taurine:2OG dioxygenase (TauD), the disposition of the substrate C-H bond relative to the vanadyl ion defined by pulse electron paramagnetic resonance methods is consistent with the crystal structure of the reactant complex and computational models of the ferryl state. Vanadyl substitution may thus afford access to structural details of the key ferryl intermediates in this important enzyme class.
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Affiliation(s)
| | | | - Megan L Matthews
- Department of Chemical Physiology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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