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Kolling D, Stierhof M, Lasch C, Myronovskyi M, Luzhetskyy A. A Promiscuous Halogenase for the Derivatization of Flavonoids. Molecules 2021; 26:molecules26206220. [PMID: 34684801 PMCID: PMC8539768 DOI: 10.3390/molecules26206220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 11/17/2022] Open
Abstract
Halogenation often improves the bioactive properties of natural products and is used in pharmaceutical research for the generation of new potential drug leads. High regio- and stereospecificity, simple reaction conditions and straightforward downstream processing are the main advantages of halogenation using enzymatic biocatalysts compared to chemical synthetic approaches. The identification of new promiscuous halogenases for the modification of various natural products is of great interest in modern drug discovery. In this paper, we report the identification of a new promiscuous FAD-dependent halogenase, DklH, from Frankia alni ACN14a. The identified halogenase readily modifies various flavonoid compounds, including those with well-studied biological activities. This halogenase has been demonstrated to modify not only flavones and isoflavones, but also flavonols, flavanones and flavanonols. The structural requirements for DklH substrate recognition were determined using a feeding approach. The homology model of DklH and the mechanism of substrate recognition are also proposed in this paper.
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Affiliation(s)
- Dominik Kolling
- Department of Pharmaceutical Biotechnology, Saarland University, 66123 Saarbruecken, Germany; (D.K.); (M.S.); (C.L.); (M.M.)
| | - Marc Stierhof
- Department of Pharmaceutical Biotechnology, Saarland University, 66123 Saarbruecken, Germany; (D.K.); (M.S.); (C.L.); (M.M.)
| | - Constanze Lasch
- Department of Pharmaceutical Biotechnology, Saarland University, 66123 Saarbruecken, Germany; (D.K.); (M.S.); (C.L.); (M.M.)
| | - Maksym Myronovskyi
- Department of Pharmaceutical Biotechnology, Saarland University, 66123 Saarbruecken, Germany; (D.K.); (M.S.); (C.L.); (M.M.)
| | - Andriy Luzhetskyy
- Department of Pharmaceutical Biotechnology, Saarland University, 66123 Saarbruecken, Germany; (D.K.); (M.S.); (C.L.); (M.M.)
- AMEG Department, Helmholtz Institute for Pharmaceutical Research Saarland, 66123 Saarbruecken, Germany
- Correspondence: ; Tel.: +49-681-302-70200
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Sana B, Ho T, Kannan S, Ke D, Li EHY, Seayad J, Verma CS, Duong HA, Ghadessy FJ. Engineered RebH Halogenase Variants Demonstrating a Specificity Switch from Tryptophan towards Novel Indole Compounds. Chembiochem 2021; 22:2791-2798. [PMID: 34240527 PMCID: PMC8518859 DOI: 10.1002/cbic.202100210] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/06/2021] [Indexed: 01/21/2023]
Abstract
Activating industrially important aromatic hydrocarbons by installing halogen atoms is extremely important in organic synthesis and often improves the pharmacological properties of drug molecules. To this end, tryptophan halogenase enzymes are potentially valuable tools for regioselective halogenation of arenes, including various industrially important indole derivatives and similar scaffolds. Although endogenous enzymes show reasonable substrate scope towards indole compounds, their efficacy can often be improved by engineering. Using a structure-guided semi-rational mutagenesis approach, we have developed two RebH variants with expanded biocatalytic repertoires that can efficiently halogenate several novel indole substrates and produce important pharmaceutical intermediates. Interestingly, the engineered enzymes are completely inactive towards their natural substrate tryptophan in spite of their high tolerance to various functional groups in the indole ring. Computational modelling and molecular dynamics simulations provide mechanistic insights into the role of gatekeeper residues in the substrate binding site and the dramatic switch in substrate specificity when these are mutated.
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Affiliation(s)
- Barindra Sana
- Disease Intervention Technology LaboratoryInstitute of Molecular and Cell BiologyAgency for Science Technology and Research (A*STAR)8 A Biomedical Grove, #06-04/05 Neuros/ImmunosSingapore138648Singapore
| | - Timothy Ho
- Institute of Chemical and Engineering SciencesAgency for Science Technology And Research (A*STAR)8 Biomedical Grove, Neuros, #07-01Singapore138665Singapore
| | - Srinivasaraghavan Kannan
- Bioinformatics InstituteAgency for Science Technology And Research (A*STAR)30 Biopolis Street, #07-01 MatrixSingapore138671Singapore
| | - Ding Ke
- Disease Intervention Technology LaboratoryInstitute of Molecular and Cell BiologyAgency for Science Technology and Research (A*STAR)8 A Biomedical Grove, #06-04/05 Neuros/ImmunosSingapore138648Singapore
| | - Eunice H. Y. Li
- Institute of Chemical and Engineering SciencesAgency for Science Technology And Research (A*STAR)8 Biomedical Grove, Neuros, #07-01Singapore138665Singapore
| | - Jayasree Seayad
- Institute of Chemical and Engineering SciencesAgency for Science Technology And Research (A*STAR)8 Biomedical Grove, Neuros, #07-01Singapore138665Singapore
| | - Chandra S. Verma
- Bioinformatics InstituteAgency for Science Technology And Research (A*STAR)30 Biopolis Street, #07-01 MatrixSingapore138671Singapore
- School of Biological SciencesNanyang Technological University60 Nanyang DriveSingapore637551Singapore
- Department of Biological SciencesNational University of Singapore14 Science Drive 4Singapore117558Singapore
| | - Hung A. Duong
- Institute of Chemical and Engineering SciencesAgency for Science Technology And Research (A*STAR)8 Biomedical Grove, Neuros, #07-01Singapore138665Singapore
| | - Farid J. Ghadessy
- Disease Intervention Technology LaboratoryInstitute of Molecular and Cell BiologyAgency for Science Technology and Research (A*STAR)8 A Biomedical Grove, #06-04/05 Neuros/ImmunosSingapore138648Singapore
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Walter A, Storch G. Synthetic C6-Functionalized Aminoflavin Catalysts Enable Aerobic Bromination of Oxidation-Prone Substrates. Angew Chem Int Ed Engl 2020; 59:22505-22509. [PMID: 32790228 PMCID: PMC7756793 DOI: 10.1002/anie.202009657] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/08/2020] [Indexed: 12/19/2022]
Abstract
Flavoenzymes catalyze oxidations via hydroperoxide intermediates that result from activation of molecular O2. These reactions—such as hydroxylation and halogenation—depend on the additional catalytic activity of functional groups in the peptide environment of the flavin cofactor. We report synthetic flavin catalysts that contain C6 amino modifications at the isoalloxazine core and are consequently capable of mediating halogenations outside the peptide surrounding. The catalysts are competent in the selective, biomimetic bromination of oxidation‐prone phenols, flavones, and flavanones using a halide salt in combination with 2,6‐lutidinium oxalate as a flavin reductant under visible‐light irradiation. Our studies show the beneficial effect of stacked bisflavins as well as the catalytic activity of the flavin modifications. The designed flavin catalysts outperform isolated natural (−)‐riboflavin and contribute to the continuing search for tailored flavins in oxidation reactions.
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Affiliation(s)
- Alexandra Walter
- Department ChemieTechnische Universität MünchenLichtenbergstr. 485747GarchingGermany
| | - Golo Storch
- Department ChemieTechnische Universität MünchenLichtenbergstr. 485747GarchingGermany
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Walter A, Storch G. Synthetische, C6‐funktionalisierte Aminoflavinkatalysatoren ermöglichen die aerobe Bromierung oxidationsanfälliger Substrate. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Alexandra Walter
- Department Chemie Technische Universität München Lichtenbergstr. 4 85747 Garching Deutschland
| | - Golo Storch
- Department Chemie Technische Universität München Lichtenbergstr. 4 85747 Garching Deutschland
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Lingkon K, Bellizzi JJ. Structure and Activity of the Thermophilic Tryptophan-6 Halogenase BorH. Chembiochem 2019; 21:1121-1128. [PMID: 31692209 DOI: 10.1002/cbic.201900667] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Indexed: 12/19/2022]
Abstract
Flavin-dependent halogenases carry out regioselective aryl halide synthesis in aqueous solution at ambient temperature and neutral pH using benign halide salts, making them attractive catalysts for green chemistry. BorH and BorF, two proteins encoded by the biosynthetic gene cluster for the chlorinated bisindole alkaloid borregomycin A, are the halogenase and flavin reductase subunits of a tryptophan-6-halogenase. Quantitative conversion of l-tryptophan (Trp) to 6-chlorotryptophan could be achieved using 1.2 mol % BorH and 2 mol % BorF. The optimal reaction temperature for Trp chlorination is 45 °C, and the melting temperatures of BorH and BorF are 48 and 50 °C respectively, which are higher than the thermal parameters for most other halogenases previously studied. Steady-state kinetic analysis of Trp chlorination by BorH determined parameters of kcat =4.42 min-1 , and KM of 9.78 μm at 45 °C. BorH exhibits a broad substrate scope, chlorinating and brominating a variety of aromatic substrates with and without indole groups. Chlorination of Trp at a 100 mg scale with 52 % crude yield, using 0.2 mol % BorH indicates that industrial scale biotransformations using BorH/BorF are feasible. The X-ray crystal structure of BorH with bound Trp provides additional evidence for the model that regioselectivity is determined by substrate positioning in the active site, showing C6 of Trp juxtaposed with the catalytic Lys79 in the same binding pose previously observed in the structure of Thal.
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Affiliation(s)
- Kazi Lingkon
- Department of Chemistry and Biochemistry, The University of Toledo, 2801 W. Bancroft St. MS 602, Toledo, OH, 43606, USA
| | - John J Bellizzi
- Department of Chemistry and Biochemistry, The University of Toledo, 2801 W. Bancroft St. MS 602, Toledo, OH, 43606, USA
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Ni J, Liu H, Tao F, Wu Y, Xu P. Remodeling of the Photosynthetic Chain Promotes Direct CO
2
Conversion into Valuable Aromatic Compounds. Angew Chem Int Ed Engl 2018; 57:15990-15994. [DOI: 10.1002/anie.201808402] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 09/24/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Ni
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Hong‐Yu Liu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Fei Tao
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Yu‐Tong Wu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Ping Xu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
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Ni J, Liu H, Tao F, Wu Y, Xu P. Remodeling of the Photosynthetic Chain Promotes Direct CO2Conversion into Valuable Aromatic Compounds. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jun Ni
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Hong‐Yu Liu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Fei Tao
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Yu‐Tong Wu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Ping Xu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences & BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
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Andorfer MC, Belsare KD, Girlich AM, Lewis JC. Aromatic Halogenation by Using Bifunctional Flavin Reductase-Halogenase Fusion Enzymes. Chembiochem 2017; 18:2099-2103. [PMID: 28879681 PMCID: PMC5898195 DOI: 10.1002/cbic.201700391] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Indexed: 11/11/2022]
Abstract
The remarkable site selectivity and broad substrate scope of flavin-dependent halogenases (FDHs) has led to much interest in their potential as biocatalysts. Multiple engineering efforts have demonstrated that FDHs can be tuned for non-native substrate scope and site selectivity. FDHs have also proven useful as in vivo biocatalysts and have been successfully incorporated into biosynthetic pathways to build new chlorinated aromatic compounds in several heterologous organisms. In both cases, reduced flavin cofactor, usually supplied by a separate flavin reductase (FR), is required. Herein, we report functional synthetic, fused FDH-FR proteins containing various FDHs and FRs joined by different linkers. We show that FDH-FR fusion proteins can increase product titers compared to the individual components for in vivo biocatalysis in Escherichia coli.
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Affiliation(s)
- Mary C Andorfer
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, SCL 302, Chicago, IL, 60637, USA
| | - Ketaki D Belsare
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, SCL 302, Chicago, IL, 60637, USA
| | - Anna M Girlich
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, SCL 302, Chicago, IL, 60637, USA
| | - Jared C Lewis
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, SCL 302, Chicago, IL, 60637, USA
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