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Knaus T, Macheroux P, Mutti FG. Fus-SMO: Kinetics, Biochemical Characterisation and In Silico Modelling of a Chimeric Styrene Monooxygenase Demonstrating Quantitative Coupling Efficiency. Chembiochem 2024; 25:e202300833. [PMID: 38306174 DOI: 10.1002/cbic.202300833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/03/2024]
Abstract
The styrene monooxygenase, a two-component enzymatic system for styrene epoxidation, was characterised through the study of Fus-SMO - a chimera resulting from the fusion of StyA and StyB using a flexible linker. Notably, it remains debated whether the transfer of FADH2 from StyB to StyA occurs through diffusion, channeling, or a combination of both. Fus-SMO was identified as a trimer with one bound FAD molecule. In silico modelling revealed a well-distanced arrangement (45-50 Å) facilitated by the flexible linker's loopy structure. Pre-steady-state kinetics elucidated the FADox reduction intricacies (kred=110 s-1 for bound FADox), identifying free FADox binding as the rate-determining step. The aerobic oxidation of FADH2 (kox=90 s-1) and subsequent decomposition to FADox and H2O2 demonstrated StyA's protective effect on the bound hydroperoxoflavin (kdec=0.2 s-1) compared to free cofactor (kdec=1.8 s-1). At varied styrene concentrations, kox for FADH2 ranged from 80 to 120 s-1. Studies on NADH consumption vs. styrene epoxidation revealed Fus-SMO's ability to achieve quantitative coupling efficiency in solution, surpassing natural two-component SMOs. The results suggest that Fus-SMO exhibits enhanced FADH2 channelling between subunits. This work contributes to comprehending FADH2 transfer mechanisms in SMO and illustrates how protein fusion can elevate catalytic efficiency for biocatalytic applications.
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Affiliation(s)
- Tanja Knaus
- Van 't Hoff Institute for Molecular Sciences, HIMS-Biocat, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12, 8010, Graz, Austria
| | - Francesco G Mutti
- Van 't Hoff Institute for Molecular Sciences, HIMS-Biocat, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands
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2
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Kratky J, Eggerichs D, Heine T, Hofmann S, Sowa P, Weiße RH, Tischler D, Sträter N. Structural and Mechanistic Studies on Substrate and Stereoselectivity of the Indole Monooxygenase VpIndA1: New Avenues for Biocatalytic Epoxidations and Sulfoxidations. Angew Chem Int Ed Engl 2023; 62:e202300657. [PMID: 36762980 DOI: 10.1002/anie.202300657] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/11/2023]
Abstract
Flavoprotein monooxygenases are a versatile group of enzymes for biocatalytic transformations. Among these, group E monooxygenases (GEMs) catalyze enantioselective epoxidation and sulfoxidation reactions. Here, we describe the crystal structure of an indole monooxygenase from the bacterium Variovorax paradoxus EPS, a GEM designated as VpIndA1. Complex structures with substrates reveal productive binding modes that, in conjunction with force-field calculations and rapid mixing kinetics, reveal the structural basis of substrate and stereoselectivity. Structure-based redesign of the substrate cavity yielded variants with new substrate selectivity (for sulfoxidation of benzyl phenyl sulfide) or with greatly enhanced stereoselectivity (from 35.1 % to 99.8 % ee for production of (1S,2R)-indene oxide). This first determination of the substrate binding mode of GEMs combined with structure-function relationships opens the door for structure-based design of these powerful biocatalysts.
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Affiliation(s)
- Julia Kratky
- Institute of Bioanalytical Chemistry, Leipzig University, Deutscher Platz 5, 04103, Leipzig, Germany
| | - Daniel Eggerichs
- Microbial Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Thomas Heine
- Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599, Freiberg, Germany
| | - Sarah Hofmann
- Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599, Freiberg, Germany
| | - Philipp Sowa
- Microbial Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Renato H Weiße
- Institute of Bioanalytical Chemistry, Leipzig University, Deutscher Platz 5, 04103, Leipzig, Germany
| | - Dirk Tischler
- Microbial Biotechnology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany.,Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599, Freiberg, Germany
| | - Norbert Sträter
- Institute of Bioanalytical Chemistry, Leipzig University, Deutscher Platz 5, 04103, Leipzig, Germany
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3
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Ernst S, Mährlein A, Ritzmann NH, Drees SL, Fetzner S. A comparative study of
N
‐hydroxylating flavoprotein monooxygenases reveals differences in kinetics and cofactor binding. FEBS J 2022; 289:5637-5655. [DOI: 10.1111/febs.16444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/21/2022] [Accepted: 03/18/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Simon Ernst
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Almuth Mährlein
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Niklas H. Ritzmann
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Steffen L. Drees
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
| | - Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology University of Münster Germany
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4
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Two (Chemo)-Enzymatic Cascades for the Production of Opposite Enantiomers of Chiral Azidoalcohols. Catalysts 2021. [DOI: 10.3390/catal11080982] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Multi-step cascade reactions have gained increasing attention in the biocatalysis field in recent years. In particular, multi-enzymatic cascades can achieve high molecular complexity without workup of reaction intermediates thanks to the enzymes’ intrinsic selectivity; and where enzymes fall short, organo- or metal catalysts can further expand the range of possible synthetic routes. Here, we present two enantiocomplementary (chemo)-enzymatic cascades composed of either a styrene monooxygenase (StyAB) or the Shi epoxidation catalyst for enantioselective alkene epoxidation in the first step, coupled with a halohydrin dehalogenase (HHDH)-catalysed regioselective epoxide ring opening in the second step for the synthesis of chiral aliphatic non-terminal azidoalcohols. Through the controlled formation of two new stereocenters, corresponding azidoalcohol products could be obtained with high regioselectivity and excellent enantioselectivity (99% ee) in the StyAB-HHDH cascade, while product enantiomeric excesses in the Shi-HHDH cascade ranged between 56 and 61%.
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Paul CE, Eggerichs D, Westphal AH, Tischler D, van Berkel WJH. Flavoprotein monooxygenases: Versatile biocatalysts. Biotechnol Adv 2021; 51:107712. [PMID: 33588053 DOI: 10.1016/j.biotechadv.2021.107712] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/27/2021] [Accepted: 02/06/2021] [Indexed: 12/13/2022]
Abstract
Flavoprotein monooxygenases (FPMOs) are single- or two-component enzymes that catalyze a diverse set of chemo-, regio- and enantioselective oxyfunctionalization reactions. In this review, we describe how FPMOs have evolved from model enzymes in mechanistic flavoprotein research to biotechnologically relevant catalysts that can be applied for the sustainable production of valuable chemicals. After a historical account of the development of the FPMO field, we explain the FPMO classification system, which is primarily based on protein structural properties and electron donor specificities. We then summarize the most appealing reactions catalyzed by each group with a focus on the different types of oxygenation chemistries. Wherever relevant, we report engineering strategies that have been used to improve the robustness and applicability of FPMOs.
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Affiliation(s)
- Caroline E Paul
- Biocatalysis, Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Daniel Eggerichs
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Dirk Tischler
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
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Enantioselective Epoxidation by Flavoprotein Monooxygenases Supported by Organic Solvents. Catalysts 2020. [DOI: 10.3390/catal10050568] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Styrene and indole monooxygenases (SMO and IMO) are two-component flavoprotein monooxygenases composed of a nicotinamide adenine dinucleotide (NADH)-dependent flavin adenine dinucleotide (FAD)-reductase (StyB or IndB) and a monooxygenase (StyA or IndA). The latter uses reduced FAD to activate oxygen and to oxygenate the substrate while releasing water. We circumvented the need for the reductase by direct FAD reduction in solution using the NAD(P)H-mimic 1-benzyl-1,4-dihydronicotinamide (BNAH) to fuel monooxygenases without NADH requirement. Herein, we report on the hitherto unknown solvent tolerance for the indole monooxygenase from Gemmobacter nectariphilus DSM15620 (GnIndA) and the styrene monooxygenase from Gordonia rubripertincta CWB2 (GrStyA). These enzymes were shown to convert bulky and rather hydrophobic styrene derivatives in the presence of organic cosolvents. Subsequently, BNAH-driven biotransformation was furthermore optimized with regard to the applied cosolvent and its concentration as well as FAD and BNAH concentration. We herein demonstrate that GnIndA and GrStyA enable selective epoxidations of allylic double bonds (up to 217 mU mg−1) in the presence of organic solvents such as tetrahydrofuran, acetonitrile, or several alcohols. Notably, GnIndA was found to resist methanol concentrations up to 25 vol.%. Furthermore, a diverse substrate preference was determined for both enzymes, making their distinct use very interesting. In general, our results seem representative for many IMOs as was corroborated by in silico mutagenetic studies.
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Tischler D, Kumpf A, Eggerichs D, Heine T. Styrene monooxygenases, indole monooxygenases and related flavoproteins applied in bioremediation and biocatalysis. FLAVIN-DEPENDENT ENZYMES: MECHANISMS, STRUCTURES AND APPLICATIONS 2020; 47:399-425. [DOI: 10.1016/bs.enz.2020.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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8
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Heine T, van Berkel WJH, Gassner G, van Pée KH, Tischler D. Two-Component FAD-Dependent Monooxygenases: Current Knowledge and Biotechnological Opportunities. BIOLOGY 2018; 7:biology7030042. [PMID: 30072664 PMCID: PMC6165268 DOI: 10.3390/biology7030042] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/11/2022]
Abstract
Flavoprotein monooxygenases create valuable compounds that are of high interest for the chemical, pharmaceutical, and agrochemical industries, among others. Monooxygenases that use flavin as cofactor are either single- or two-component systems. Here we summarize the current knowledge about two-component flavin adenine dinucleotide (FAD)-dependent monooxygenases and describe their biotechnological relevance. Two-component FAD-dependent monooxygenases catalyze hydroxylation, epoxidation, and halogenation reactions and are physiologically involved in amino acid metabolism, mineralization of aromatic compounds, and biosynthesis of secondary metabolites. The monooxygenase component of these enzymes is strictly dependent on reduced FAD, which is supplied by the reductase component. More and more representatives of two-component FAD-dependent monooxygenases have been discovered and characterized in recent years, which has resulted in the identification of novel physiological roles, functional properties, and a variety of biocatalytic opportunities.
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Affiliation(s)
- Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - George Gassner
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
| | - Karl-Heinz van Pée
- Allgemeine Biochemie, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
- Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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9
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Tischler D, Schwabe R, Siegel L, Joffroy K, Kaschabek SR, Scholtissek A, Heine T. VpStyA1/VpStyA2B of Variovorax paradoxus EPS: An Aryl Alkyl Sulfoxidase Rather than a Styrene Epoxidizing Monooxygenase. Molecules 2018; 23:E809. [PMID: 29614810 PMCID: PMC6017014 DOI: 10.3390/molecules23040809] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 03/27/2018] [Accepted: 04/01/2018] [Indexed: 02/08/2023] Open
Abstract
Herein we describe the first representative of an E2-type two-component styrene monooxygenase of proteobacteria. It comprises a single epoxidase protein (VpStyA1) and a two domain protein (VpStyA2B) harboring an epoxidase (A2) and a FAD-reductase (B) domain. It was annotated as VpStyA1/VpStyA2B of Variovorax paradoxus EPS. VpStyA2B serves mainly as NADH:FAD-oxidoreductase. A Km of 33.6 ± 4.0 µM for FAD and a kcat of 22.3 ± 1.1 s-1 were determined and resulted in a catalytic efficiency (kcatKm-1) of 0.64 s-1 μM-1. To investigate its NADH:FAD-oxidoreductase function the linker between A2- and B-domain (AREAV) was mutated. One mutant (AAAAA) showed 18.7-fold higher affinity for FAD (kcatKm-1 of 5.21 s-1 μM-1) while keeping wildtype NADH-affinity and -oxidation activity. Both components, VpStyA2B and VpStyA1, showed monooxygenase activity on styrene of 0.14 U mg-1 and 0.46 U mg-1, as well as on benzyl methyl sulfide of 1.62 U mg-1 and 3.11 U mg-1, respectively. The high sulfoxidase activity was the reason to test several thioanisole-like substrates in biotransformations. VpStyA1 showed high substrate conversions (up to 95% in 2 h) and produced dominantly (S)-enantiomeric sulfoxides of all tested substrates. The AAAAA-mutant showed a 1.6-fold increased monooxygenase activity. In comparison, the GQWCSQY-mutant did neither show monooxygenase nor efficient FAD-reductase activity. Hence, the linker between the two domains of VpStyA2B has effects on the reductase as well as on the monooxygenase performance. Overall, this monooxygenase represents a promising candidate for biocatalyst development and studying natural fusion proteins.
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Affiliation(s)
- Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
- Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Ringo Schwabe
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Lucas Siegel
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Kristin Joffroy
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Stefan R Kaschabek
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Anika Scholtissek
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
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10
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Oelschlägel M, Zimmerling J, Tischler D. A Review: The Styrene Metabolizing Cascade of Side-Chain Oxygenation as Biotechnological Basis to Gain Various Valuable Compounds. Front Microbiol 2018; 9:490. [PMID: 29623070 PMCID: PMC5874493 DOI: 10.3389/fmicb.2018.00490] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/02/2018] [Indexed: 11/16/2022] Open
Abstract
Styrene is one of the most produced and processed chemicals worldwide and is released into the environment during widespread processing. But, it is also produced from plants and microorganisms. The natural occurrence of styrene led to several microbiological strategies to form and also to degrade styrene. One pathway designated as side-chain oxygenation has been reported as a specific route for the styrene degradation among microorganisms. It comprises the following enzymes: styrene monooxygenase (SMO; NADH-consuming and FAD-dependent, two-component system), styrene oxide isomerase (SOI; cofactor independent, membrane-bound protein) and phenylacetaldehyde dehydrogenase (PAD; NAD+-consuming) and allows an intrinsic cofactor regeneration. This specific way harbors a high potential for biotechnological use. Based on the enzymatic steps involved in this degradation route, important reactions can be realized from a large number of substrates which gain access to different interesting precursors for further applications. Furthermore, stereochemical transformations are possible, offering chiral products at high enantiomeric excess. This review provides an actual view on the microbiological styrene degradation followed by a detailed discussion on the enzymes of the side-chain oxygenation. Furthermore, the potential of the single enzyme reactions as well as the respective multi-step syntheses using the complete enzyme cascade are discussed in order to gain styrene oxides, phenylacetaldehydes, or phenylacetic acids (e.g., ibuprofen). Altered routes combining these putative biocatalysts with other enzymes are additionally described. Thus, the substrates spectrum can be enhanced and additional products as phenylethanols or phenylethylamines are reachable. Finally, additional enzymes with similar activities toward styrene and its metabolic intermediates are shown in order to modify the cascade described above or to use these enzyme independently for biotechnological application.
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Affiliation(s)
- Michel Oelschlägel
- Environmental Microbiology Group, Institute of Biosciences, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Juliane Zimmerling
- Environmental Microbiology Group, Institute of Biosciences, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Dirk Tischler
- Environmental Microbiology Group, Institute of Biosciences, Technische Universität Bergakademie Freiberg, Freiberg, Germany
- Microbial Biotechnology, Ruhr University Bochum, Bochum, Germany
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11
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Heine T, Scholtissek A, Westphal AH, van Berkel WJH, Tischler D. N-terminus determines activity and specificity of styrene monooxygenase reductases. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1770-1780. [PMID: 28888693 DOI: 10.1016/j.bbapap.2017.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/10/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Abstract
Styrene monooxygenases (SMOs) are two-enzyme systems that catalyze the enantioselective epoxidation of styrene to (S)-styrene oxide. The FADH2 co-substrate of the epoxidase component (StyA) is supplied by an NADH-dependent flavin reductase (StyB). The genome of Rhodococcus opacus 1CP encodes two SMO systems. One system, which we define as E1-type, displays homology to the SMO from Pseudomonas taiwanensis VLB120. The other system, originally reported as a fused system (RoStyA2B), is defined as E2-type. Here we found that E1-type RoStyB is inhibited by FMN, while RoStyA2B is known to be active with FMN. To rationalize the observed specificity of RoStyB for FAD, we generated an artificial reductase, designated as RoStyBart, in which the first 22 amino acid residues of RoStyB were joined to the reductase part of RoStyA2B, while the oxygenase part (A2) was removed. RoStyBart mainly purified as apo-protein and mimicked RoStyB in being inhibited by FMN. Pre-incubation with FAD yielded a turnover number at 30°C of 133.9±3.5s-1, one of the highest rates observed for StyB reductases. RoStyBart holo-enzyme switches to a ping-pong mechanism and fluorescence analysis indicated for unproductive binding of FMN to the second (co-substrate) binding site. In summary, it is shown for the first time that optimization of the N-termini of StyB reductases allows the evolution of their activity and specificity.
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Affiliation(s)
- Thomas Heine
- Environmental Microbiology, Interdisciplinary Ecological Center, TU Bergakadmie Freiberg, Leipziger Straße 29, 09599 Freiberg, Germany; Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Anika Scholtissek
- Environmental Microbiology, Interdisciplinary Ecological Center, TU Bergakadmie Freiberg, Leipziger Straße 29, 09599 Freiberg, Germany; Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Dirk Tischler
- Environmental Microbiology, Interdisciplinary Ecological Center, TU Bergakadmie Freiberg, Leipziger Straße 29, 09599 Freiberg, Germany.
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12
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Latham J, Brandenburger E, Shepherd SA, Menon BRK, Micklefield J. Development of Halogenase Enzymes for Use in Synthesis. Chem Rev 2017; 118:232-269. [PMID: 28466644 DOI: 10.1021/acs.chemrev.7b00032] [Citation(s) in RCA: 207] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nature has evolved halogenase enzymes to regioselectively halogenate a diverse range of biosynthetic precursors, with the halogens introduced often having a profound effect on the biological activity of the resulting natural products. Synthetic endeavors to create non-natural bioactive small molecules for pharmaceutical and agrochemical applications have also arrived at a similar conclusion: halogens can dramatically improve the properties of organic molecules for selective modulation of biological targets in vivo. Consequently, a high proportion of pharmaceuticals and agrochemicals on the market today possess halogens. Halogenated organic compounds are also common intermediates in synthesis and are particularly valuable in metal-catalyzed cross-coupling reactions. Despite the potential utility of organohalogens, traditional nonenzymatic halogenation chemistry utilizes deleterious reagents and often lacks regiocontrol. Reliable, facile, and cleaner methods for the regioselective halogenation of organic compounds are therefore essential in the development of economical and environmentally friendly industrial processes. A potential avenue toward such methods is the use of halogenase enzymes, responsible for the biosynthesis of halogenated natural products, as biocatalysts. This Review will discuss advances in developing halogenases for biocatalysis, potential untapped sources of such biocatalysts and how further optimization of these enzymes is required to achieve the goal of industrial scale biohalogenation.
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Affiliation(s)
- Jonathan Latham
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Eileen Brandenburger
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Sarah A Shepherd
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Binuraj R K Menon
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Jason Micklefield
- School of Chemistry and Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
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Heine T, Tucker K, Okonkwo N, Assefa B, Conrad C, Scholtissek A, Schlömann M, Gassner G, Tischler D. Engineering Styrene Monooxygenase for Biocatalysis: Reductase-Epoxidase Fusion Proteins. Appl Biochem Biotechnol 2016; 181:1590-1610. [PMID: 27830466 DOI: 10.1007/s12010-016-2304-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/24/2016] [Indexed: 11/25/2022]
Abstract
The enantioselective epoxidation of styrene and related compounds by two-component styrene monooxygenases (SMOs) has targeted these enzymes for development as biocatalysts. In the present work, we prepare genetically engineered fusion proteins that join the C-terminus of the epoxidase (StyA) to the N-terminus of the reductase (StyB) through a linker peptide and demonstrate their utility as biocatalysts in the synthesis of Tyrain purple and other indigoid dyes. A single-vector expression system offers a simplified platform for transformation and expansion of the catalytic function of styrene monooxygenases, and the resulting fusion proteins are self-regulated and couple efficiently NADH oxidation to styrene epoxidation. We find that the reductase domain proceeds through a sequential ternary-complex mechanism at low FAD concentration and a double-displacement mechanism at higher concentrations of FAD. Single-turnover studies indicate an observed rate constant for FAD-to-FAD hydride transfer of ~8 s-1. This step is rate limiting in the styrene epoxidation reaction and helps to ensure that flavin reduction and styrene epoxidation reactions proceed without wasteful side reactions. Comparison of the reductase activity of the fusion proteins with the naturally occurring reductase, SMOB, and N-terminally histidine-tagged reductase, NSMOB, suggests that the observed changes in catalytic mechanism are due in part to an increase in flavin-binding affinity associated with the N-terminal extension of the reductase.
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Affiliation(s)
| | | | - Nonye Okonkwo
- San Francisco State University, San Francisco, CA, USA
| | | | | | | | | | | | - Dirk Tischler
- TU Bergakademie Freiberg, Freiberg, Germany.
- San Francisco State University, San Francisco, CA, USA.
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Holtmann D, Hollmann F. The Oxygen Dilemma: A Severe Challenge for the Application of Monooxygenases? Chembiochem 2016; 17:1391-8. [PMID: 27194219 PMCID: PMC5096067 DOI: 10.1002/cbic.201600176] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 12/12/2022]
Abstract
Monooxygenases are promising catalysts because they in principle enable the organic chemist to perform highly selective oxyfunctionalisation reactions that are otherwise difficult to achieve. For this, monooxygenases require reducing equivalents, to allow reductive activation of molecular oxygen at the enzymes' active sites. However, these reducing equivalents are often delivered to O2 either directly or via a reduced intermediate (uncoupling), yielding hazardous reactive oxygen species and wasting valuable reducing equivalents. The oxygen dilemma arises from monooxygenases' dependency on O2 and the undesired uncoupling reaction. With this contribution we hope to generate a general awareness of the oxygen dilemma and to discuss its nature and some promising solutions.
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Affiliation(s)
- Dirk Holtmann
- DECHEMA Research Institute, Theodor-Heuss-Allee 25, 60486, Frankfurt am Main, Germany
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Julianalaan 136, 2628BL, Delft, The Netherlands.
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Holtmann D, Fraaije MW, Arends IWCE, Opperman DJ, Hollmann F. The taming of oxygen: biocatalytic oxyfunctionalisations. Chem Commun (Camb) 2015; 50:13180-200. [PMID: 24902635 DOI: 10.1039/c3cc49747j] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The scope and limitations of oxygenases as catalysts for preparative organic synthesis is discussed.
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Affiliation(s)
- Dirk Holtmann
- DECHEMA Research Institute, Theodor-Heuss-Allee 25, 60486 Frankfurt am Main, Germany
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Huijbers MME, Montersino S, Westphal AH, Tischler D, van Berkel WJH. Flavin dependent monooxygenases. Arch Biochem Biophys 2013; 544:2-17. [PMID: 24361254 DOI: 10.1016/j.abb.2013.12.005] [Citation(s) in RCA: 369] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 11/29/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of chemo-, regio- and enantioselective oxygenation reactions. As such, they are involved in key biological processes ranging from catabolism, detoxification and biosynthesis, to light emission and axon guidance. Based on fold and function, flavin-dependent monooxygenases can be distributed into eight groups. Groups A and B comprise enzymes that rely on NAD(P)H as external electron donor. Groups C-F are two-protein systems, composed of a monooxygenase and a flavin reductase. Groups G and H comprise internal monooxygenases that reduce the flavin cofactor through substrate oxidation. Recently, many new flavin-dependent monooxygenases have been discovered. In addition to posing basic enzymological questions, these proteins attract attention of pharmaceutical and fine-chemical industries, given their importance as regio- and enantioselective biocatalysts. In this review we present an update of the classification of flavin-dependent monooxygenases and summarize the latest advances in our understanding of their catalytic and structural properties.
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Affiliation(s)
- Mieke M E Huijbers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Stefania Montersino
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Dirk Tischler
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands; Interdisciplinary Ecological Center, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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