1
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Bopp C, Bernet NM, Meyer F, Khan R, Robinson SL, Kohler HPE, Buller R, Hofstetter TB. Elucidating the Role of O 2 Uncoupling for the Adaptation of Bacterial Biodegradation Reactions Catalyzed by Rieske Oxygenases. ACS ENVIRONMENTAL AU 2024; 4:204-218. [PMID: 39035869 PMCID: PMC11258757 DOI: 10.1021/acsenvironau.4c00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 07/23/2024]
Abstract
Oxygenation of aromatic and aliphatic hydrocarbons by Rieske oxygenases is the initial step of various biodegradation pathways for environmental organic contaminants. Microorganisms carrying Rieske oxygenases are able to quickly adapt their substrate spectra to alternative carbon and energy sources that are structurally related to the original target substrate, yet the molecular events responsible for this rapid adaptation are not well understood. Here, we evaluated the hypothesis that reactive oxygen species (ROS) generated by unproductive activation of O2, the so-called O2 uncoupling, in the presence of the alternative substrate exert a selective pressure on the bacterium for increasing the oxygenation efficiency of Rieske oxygenases. To that end, we studied wild-type 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 and five enzyme variants that have evolved from adaptive laboratory evolution experiments with 3- and 4-nitrotoluene as alternative growth substrates. The enzyme variants showed a substantially increased oxygenation efficiency toward the new target substrates concomitant with a reduction of ROS production, while mechanisms and kinetics of enzymatic O2 activation remained unchanged. Structural analyses and docking studies suggest that amino acid substitutions in enzyme variants occurred at residues lining both substrate and O2 transport tunnels, enabling tighter binding of the target substrates in the active site. Increased oxygenation efficiencies measured in vitro for the various enzyme (variant)-substrate combinations correlated linearly with in vivo changes in growth rates for evolved Acidovorax strains expressing the variants. Our data suggest that the selective pressure from oxidative stress toward more efficient oxygenation by Rieske oxygenases was most notable when O2 uncoupling exceeded 60%.
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Affiliation(s)
- Charlotte
E. Bopp
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Nora M. Bernet
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Fabian Meyer
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Riyaz Khan
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Serina L. Robinson
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Hans-Peter E. Kohler
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Rebecca Buller
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Thomas B. Hofstetter
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
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2
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Li Q, Zhang S, Liu F, Su H, Sheng X. Quantum chemical modeling of enantioselective sulfoxidation and epoxidation reactions by indole monooxygenase VpIndA1. Phys Chem Chem Phys 2024; 26:16521-16528. [PMID: 38809594 DOI: 10.1039/d4cp00552j] [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: 05/30/2024]
Abstract
Indole monooxygenases (IMOs) are enzymes from the family of Group E monooxygenases, requiring flavin adenine dinucleotide (FAD) for their activities. IMOs play important roles in both sulfoxidation and epoxidation reactions. The broad substrate range and high selectivity of IMOs make them promising biocatalytic tools for synthesizing chiral compounds. In the present study, quantum chemical calculations using the cluster approach were performed to investigate the reaction mechanism and the enantioselectivity of the IMO from Variovorax paradoxus EPS (VpIndA1). The sulfoxidation of methyl phenyl sulfide (MPS) and the epoxidation of indene were chosen as the representative reactions. The calculations confirmed that the FADOOH intermediate is the catalytic species in the VpIndA1 reactions. The oxidation of MPS adopts a one-step mechanism involving the direct oxygen-transfer from FADOOH to the substrate and the proton transfer from the -OH group back to FAD, while the oxidation of indene follows a stepwise mechanism involving a carbocation intermediate. It was computationally predicted that VpIndA1 prefers the formation of (S)-product for the MPS sulfoxidation and (1S,2R)-product for the indene epoxidation, consistent with the experimental observations. Importantly, the factors controlling the stereo-preference of the two reactions are identified. The findings in the present study provide valuable insights into the VpIndA1-catalyzed reactions, which are essential for the rational design of this enzyme and other IMOs for industrial applications. It is also worth emphasizing that the quantum chemical cluster approach is again demonstrated to be powerful in studying the enantioselectivity of enzymatic reactions.
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Affiliation(s)
- Qinrou Li
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, P. R. China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China.
| | - Shiqing Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China.
- National Center of Technology Innovation for Synthetic Biology, National Engineering Research Center of Industrial Enzymes and Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin 300308, P. R. China
| | - Fufeng Liu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, P. R. China
| | - Hao Su
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China.
- National Center of Technology Innovation for Synthetic Biology, National Engineering Research Center of Industrial Enzymes and Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin 300308, P. R. China
| | - Xiang Sheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, P. R. China.
- National Center of Technology Innovation for Synthetic Biology, National Engineering Research Center of Industrial Enzymes and Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin 300308, P. R. China
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3
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Shi T, Sun X, Yuan Q, Wang J, Shen X. Exploring the role of flavin-dependent monooxygenases in the biosynthesis of aromatic compounds. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:46. [PMID: 38520003 PMCID: PMC10958861 DOI: 10.1186/s13068-024-02490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Hydroxylated aromatic compounds exhibit exceptional biological activities. In the biosynthesis of these compounds, three types of hydroxylases are commonly employed: cytochrome P450 (CYP450), pterin-dependent monooxygenase (PDM), and flavin-dependent monooxygenase (FDM). Among these, FDM is a preferred choice due to its small molecular weight, stable expression in both prokaryotic and eukaryotic fermentation systems, and a relatively high concentration of necessary cofactors. However, the catalytic efficiency of many FDMs falls short of meeting the demands of large-scale production. Additionally, challenges arise from the limited availability of cofactors and compatibility issues among enzyme components. Recently, significant progress has been achieved in improving its catalytic efficiency, but have not yet detailed and informative viewed so far. Therefore, this review emphasizes the advancements in FDMs for the biosynthesis of hydroxylated aromatic compounds and presents a summary of three strategies aimed at enhancing their catalytic efficiency: (a) Developing efficient enzyme mutants through protein engineering; (b) enhancing the supply and rapid circulation of critical cofactors; (c) facilitating cofactors delivery for enhancing FDMs catalytic efficiency. Furthermore, the current challenges and further perspectives on improving catalytic efficiency of FDMs are also discussed.
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Affiliation(s)
- Tong Shi
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Xinxiao Sun
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China
| | - Jia Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
| | - Xiaolin Shen
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
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4
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Sun P, Xu S, Tian Y, Chen P, Wu D, Zheng P. 4-Hydroxyphenylacetate 3-Hydroxylase (4HPA3H): A Vigorous Monooxygenase for Versatile O-Hydroxylation Applications in the Biosynthesis of Phenolic Derivatives. Int J Mol Sci 2024; 25:1222. [PMID: 38279222 PMCID: PMC10816480 DOI: 10.3390/ijms25021222] [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: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
4-Hydroxyphenylacetate 3-hydroxylase (4HPA3H) is a long-known class of two-component flavin-dependent monooxygenases from bacteria, including an oxygenase component (EC 1.14.14.9) and a reductase component (EC 1.5.1.36), with the latter being accountable for delivering the cofactor (reduced flavin) essential for o-hydroxylation. 4HPA3H has a broad substrate spectrum involved in key biological processes, including cellular catabolism, detoxification, and the biosynthesis of bioactive molecules. Additionally, it specifically hydroxylates the o-position of the C4 position of the benzene ring in phenolic compounds, generating high-value polyhydroxyphenols. As a non-P450 o-hydroxylase, 4HPA3H offers a viable alternative for the de novo synthesis of valuable natural products. The enzyme holds the potential to replace plant-derived P450s in the o-hydroxylation of plant polyphenols, addressing the current significant challenge in engineering specific microbial strains with P450s. This review summarizes the source distribution, structural properties, and mechanism of 4HPA3Hs and their application in the biosynthesis of natural products in recent years. The potential industrial applications and prospects of 4HPA3H biocatalysts are also presented.
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Affiliation(s)
| | | | | | | | | | - Pu Zheng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (P.S.); (Y.T.); (P.C.); (D.W.)
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5
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Salerno KM, Domenico J, Le NQ, Balakrishnan K, McQuillen RJ, Stiles CD, Solov'yov IA, Martino CF. Long-Time Oxygen and Superoxide Localization in Arabidopsis thaliana Cryptochrome. J Chem Inf Model 2023; 63:6756-6767. [PMID: 37874902 DOI: 10.1021/acs.jcim.3c00325] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Cryptochromes are proteins that are highly conserved across species and in many instances bind the flavin adenine dinucleotide (FAD) cofactor within their photolyase-homology region (PHR) domain. The FAD cofactor has multiple redox states that help catalyze reactions, and absorbs photons at about 450 nm, a feature linked to the light-related functions of cryptochrome proteins. Reactive oxygen species (ROS) are produced from redox reactions involving molecular oxygen and are involved in a myriad of biological processes. Superoxide O2•- is an exemplary ROS that may be formed through electron transfer from FAD to O2, generating an electron radical pair. Although the formation of a superoxide-FAD radical pair has been speculated, it is still unclear if the required process steps could be realized in cryptochrome. Here, we present results from molecular dynamics (MD) simulations of oxygen interacting with the PHR domain of Arabidopsis thaliana cryptochrome 1 (AtCRY1). Using MD simulation trajectories, oxygen binding locations are characterized through both the O2-FAD intermolecular distance and the local protein environment. Oxygen unbinding times are characterized through replica simulations of the bound oxygen. Simulations reveal that oxygen molecules can localize at certain sites within the cryptochrome protein for tens of nanoseconds, and superoxide molecules can localize for significantly longer. This relatively long-duration molecule binding suggests the possibility of an electron-transfer reaction leading to superoxide formation. Estimates of electron-transfer rates using the Marcus theory are performed for the identified potential binding sites. Molecular oxygen binding results are compared with recent results demonstrating long-time oxygen binding within the electron-transfer flavoprotein (ETF), another FAD binding protein.
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Affiliation(s)
- K Michael Salerno
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Janna Domenico
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Nam Q Le
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Krithika Balakrishnan
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Ryan J McQuillen
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Christopher D Stiles
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
- Centre for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
- Centre for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
| | - Carlos F Martino
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
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6
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Dulchavsky M, Mitra R, Wu K, Li J, Boer K, Liu X, Zhang Z, Vasquez C, Clark CT, Funckes K, Shankar K, Bonnet-Zahedi S, Siddiq M, Sepulveda Y, Suhandynata RT, Momper JD, Calabrese AN, George O, Stull F, Bardwell JCA. Directed evolution unlocks oxygen reactivity for a nicotine-degrading flavoenzyme. Nat Chem Biol 2023; 19:1406-1414. [PMID: 37770699 PMCID: PMC10611581 DOI: 10.1038/s41589-023-01426-y] [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: 01/06/2023] [Accepted: 08/23/2023] [Indexed: 09/30/2023]
Abstract
The flavoenzyme nicotine oxidoreductase (NicA2) is a promising injectable treatment to aid in the cessation of smoking, a behavior responsible for one in ten deaths worldwide. NicA2 acts by degrading nicotine in the bloodstream before it reaches the brain. Clinical use of NicA2 is limited by its poor catalytic activity in the absence of its natural electron acceptor CycN. Without CycN, NicA2 is instead oxidized slowly by dioxygen (O2), necessitating unfeasibly large doses in a therapeutic setting. Here, we report a genetic selection strategy that directly links CycN-independent activity of NicA2 to growth of Pseudomonas putida S16. This selection enabled us to evolve NicA2 variants with substantial improvement in their rate of oxidation by O2. The encoded mutations cluster around a putative O2 tunnel, increasing flexibility and accessibility to O2 in this region. These mutations further confer desirable clinical properties. A variant form of NicA2 is tenfold more effective than the wild type at degrading nicotine in the bloodstream of rats.
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Affiliation(s)
- Mark Dulchavsky
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Rishav Mitra
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Kevin Wu
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Joshua Li
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Karli Boer
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Xiaomeng Liu
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Zhiyao Zhang
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Cristian Vasquez
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | | | - Kaitrin Funckes
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Kokila Shankar
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Selene Bonnet-Zahedi
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Mohammad Siddiq
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yadira Sepulveda
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
| | - Raymond T Suhandynata
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Jeremiah D Momper
- School of Pharmacy and Pharmaceutical Science, University of California, San Diego, La Jolla, CA, USA
| | - Antonio N Calabrese
- Astbury Centre for Structural Molecular Biology, S chool of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Olivier George
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - James C A Bardwell
- Howard Hughes Medical Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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7
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Bui S, Gil-Guerrero S, van der Linden P, Carpentier P, Ceccarelli M, Jambrina PG, Steiner RA. Evolutionary adaptation from hydrolytic to oxygenolytic catalysis at the α/β-hydrolase fold. Chem Sci 2023; 14:10547-10560. [PMID: 37799987 PMCID: PMC10548524 DOI: 10.1039/d3sc03044j] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Protein fold adaptation to novel enzymatic reactions is a fundamental evolutionary process. Cofactor-independent oxygenases degrading N-heteroaromatic substrates belong to the α/β-hydrolase (ABH) fold superfamily that typically does not catalyze oxygenation reactions. Here, we have integrated crystallographic analyses under normoxic and hyperoxic conditions with molecular dynamics and quantum mechanical calculations to investigate its prototypic 1-H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (HOD) member. O2 localization to the "oxyanion hole", where catalysis occurs, is an unfavorable event and the direct competition between dioxygen and water for this site is modulated by the "nucleophilic elbow" residue. A hydrophobic pocket that overlaps with the organic substrate binding site can act as a proximal dioxygen reservoir. Freeze-trap pressurization allowed the structure of the ternary complex with a substrate analogue and O2 bound at the oxyanion hole to be determined. Theoretical calculations reveal that O2 orientation is coupled to the charge of the bound organic ligand. When 1-H-3-hydroxy-4-oxoquinaldine is uncharged, O2 binds with its molecular axis along the ligand's C2-C4 direction in full agreement with the crystal structure. Substrate activation triggered by deprotonation of its 3-OH group by the His-Asp dyad, rotates O2 by approximately 60°. This geometry maximizes the charge transfer between the substrate and O2, thus weakening the double bond of the latter. Electron density transfer to the O2(π*) orbital promotes the formation of the peroxide intermediate via intersystem crossing that is rate-determining. Our work provides a detailed picture of how evolution has repurposed the ABH-fold architecture and its simple catalytic machinery to accomplish metal-independent oxygenation.
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Affiliation(s)
- Soi Bui
- Randall Centre for Cell and Molecular Biophysics, King's College London London SE1 1UL UK
| | - Sara Gil-Guerrero
- Departamento de Química Física, University of Salamanca Salamanca 37008 Spain
| | - Peter van der Linden
- European Synchrotron Radiation Facility (ESRF), Partnership for Soft Condensed Matter (PSCM) 71 Avenue des Martyrs Grenoble 38000 France
| | - Philippe Carpentier
- European Synchrotron Radiation Facility (ESRF) 71 Avenue des Martyrs 38043 Grenoble France
- Université Grenoble Alpes, CNRS, CEA, Interdisciplinary Research Institute of Grenoble (IRIG), Laboratoire Chimie et Biologie des Métaux (LCBM) UMR 5249 17 Avenue des Martyrs 38054 Grenoble France
| | - Matteo Ceccarelli
- Department of Physics, University of Cagliari Monserrato 09042 Italy
- IOM-CNR Unità di Cagliari, Cittadella Universitaria Monserrato 09042 Italy
| | - Pablo G Jambrina
- Departamento de Química Física, University of Salamanca Salamanca 37008 Spain
| | - Roberto A Steiner
- Randall Centre for Cell and Molecular Biophysics, King's College London London SE1 1UL UK
- Department of Biomedical Sciences, University of Padova Italy
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8
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Rafighi P, Nordberg Karlsson E, Zubaida Gulshan Ara K, Pankratova G, Bollella P, Peterbauer CK, Gorton L. A novel membraneless β-glucan/O 2 enzymatic fuel cell based on β-glucosidase (RmBgl3B)/pyranose dehydrogenase (AmPDH) co-immobilized onto buckypaper electrode. Bioelectrochemistry 2022; 148:108254. [PMID: 36122427 DOI: 10.1016/j.bioelechem.2022.108254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/02/2022]
Abstract
A novel membraneless β-glucan/O2 enzymatic fuel cell was developed by combining a bioanode based on buckypaper modified with co-immobilized Agaricus meleagris pyranose dehydrogenase (AmPDH) and Rhodothermus marinus β-glucosidase (RmBgl3B) (RmBgl3B-AmPDH/buckypaper) with a biocathode based on solid graphite modified with Myrothecium verrucaria bilirubin oxidase (MvBOx/graphite). AmPDH was connected electrochemically with the buckypaper using an osmium redox polymer in a mediated reaction, whereas MvBOx was connected with graphite in a direct electron transfer reaction. The fuel for the bioanode was produced by enzymatic hydrolysis of β-glucan by the exoglucanase RmBgl3B into d-glucose, which in turn was enzymatically oxidised by AmPDH to generate a current response. This design allows to obtain an efficient enzymatic fuel cell, where the chemical energy converted into electrical energy is higher than the chemical energy stored in complex carbohydrate based fuel. The maximum power density of the assembled β-glucan/O2 biofuel cell reached 26.3 ± 4.6 μWcm-2 at 0.36 V in phosphate buffer containing 0.5 % (w/v) β-glucan at 40 °C with excellent stability retaining 68.6 % of its initial performance after 5 days. The result confirms that β-glucan can be employed as fuel in an enzymatic biofuel cell.
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Affiliation(s)
- Parvin Rafighi
- College of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Gava Zang, Zanjan, Iran
| | | | | | - Galina Pankratova
- National Centre for Nano Fabrication and Characterization, Technical University of Denmark (DTU), Kongens Lyngby, Denmark
| | - Paolo Bollella
- Department of Chemistry, University of Bari A. Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Clemens K Peterbauer
- Department of Food Sciences and Technology BOKU-University of Natural Resources and Life Sciences Muthgasse 18, A-1190 Wien, Austria
| | - Lo Gorton
- Department of Biochemistry and Structural Biology, Lund University, PO Box 124, 221 00 Lund, Sweden.
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9
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At least three xenon binding sites in the glycine binding domain of the N-methyl D-aspartate receptor. Arch Biochem Biophys 2022; 724:109265. [DOI: 10.1016/j.abb.2022.109265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/21/2022]
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10
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Improving the kinetic parameters of nicotine oxidizing enzymes by homologous structure comparison and rational design. Arch Biochem Biophys 2022; 718:109122. [DOI: 10.1016/j.abb.2022.109122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/17/2021] [Accepted: 01/14/2022] [Indexed: 11/17/2022]
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11
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Abstract
We have structure, a wealth of kinetic data, thousands of chemical ligands and clinical information for the effects of a range of drugs on monoamine oxidase activity in vivo. We have comparative information from various species and mutations on kinetics and effects of inhibition. Nevertheless, there are what seem like simple questions still to be answered. This article presents a brief summary of existing experimental evidence the background and poses questions that remain intriguing for chemists and biochemists researching the chemical enzymology of and drug design for monoamine oxidases (FAD-containing EC 4.1.3.4).
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12
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Toward scalable biocatalytic conversion of 5-hydroxymethylfurfural by galactose oxidase using coordinated reaction and enzyme engineering. Nat Commun 2021; 12:4946. [PMID: 34400632 PMCID: PMC8367993 DOI: 10.1038/s41467-021-25034-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 07/06/2021] [Indexed: 02/05/2023] Open
Abstract
5-Hydroxymethylfurfural (HMF) has emerged as a crucial bio-based chemical building block in the drive towards developing materials from renewable resources, due to its direct preparation from sugars and its readily diversifiable scaffold. A key obstacle in transitioning to bio-based plastic production lies in meeting the necessary industrial production efficiency, particularly in the cost-effective conversion of HMF to valuable intermediates. Toward addressing the challenge of developing scalable technology for oxidizing crude HMF to more valuable chemicals, here we report coordinated reaction and enzyme engineering to provide a galactose oxidase (GOase) variant with remarkably high activity toward HMF, improved O2 binding and excellent productivity (>1,000,000 TTN). The biocatalyst and reaction conditions presented here for GOase catalysed selective oxidation of HMF to 2,5-diformylfuran offers a productive blueprint for further development, giving hope for the creation of a biocatalytic route to scalable production of furan-based chemical building blocks from sustainable feedstocks. 5-Hydroxymethylfurfural (HMF) can be transformed to a range of industrially useful derivatives, such as 2,5-diformylfuran (DFF), but the reactions needed for efficient industrial production are hindered by several issues. Here, the authors perform reaction and enzyme engineering resulting in a galactose oxidase variant with high activity towards HMF, improved oxygen binding and high productivity.
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13
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Narayan B, Buchete NV, Elber R. Computer Simulations of the Dissociation Mechanism of Gleevec from Abl Kinase with Milestoning. J Phys Chem B 2021; 125:5706-5715. [PMID: 33930271 DOI: 10.1021/acs.jpcb.1c00264] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gleevec (a.k.a., imatinib) is an important anticancer (e.g., chronic myeloid leukemia) chemotherapeutic drug due to its inhibitory interaction with the Abl kinase. Here, we use atomically detailed simulations within the Milestoning framework to study the molecular dissociation mechanism of Gleevec from Abl kinase. We compute the dissociation free energy profile, the mean first passage time for unbinding, and explore the transition state ensemble of conformations. The milestones form a multidimensional network with average connectivity of about 2.93, which is significantly higher than the connectivity for a one-dimensional reaction coordinate. The free energy barrier for Gleevec dissociation is estimated to be ∼10 kcal/mol, and the exit time is ∼55 ms. We examined the transition state conformations using both, the committor and transition function. We show that near the transition state the highly conserved salt bridge K217 and E286 is transiently broken. Together with the calculated free energy profile, these calculations can advance the understanding of the molecular interaction mechanisms between Gleevec and Abl kinase and play a role in future drug design and optimization studies.
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Affiliation(s)
- Brajesh Narayan
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland.,Institute for Discovery, University College Dublin, Belfield, Dublin 4, Ireland
| | - Nicolae-Viorel Buchete
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland.,Institute for Discovery, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ron Elber
- Oden Institute for Computational Engineering and Science, Department of Chemistry, University of Texas at Austin, Austin Texas 78712, United States
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14
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Lahham M, Jha S, Goj D, Macheroux P, Wallner S. The family of sarcosine oxidases: Same reaction, different products. Arch Biochem Biophys 2021; 704:108868. [PMID: 33812916 DOI: 10.1016/j.abb.2021.108868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 12/11/2022]
Abstract
The subfamily of sarcosine oxidase is a set of enzymes within the larger family of amine oxidases. It is ubiquitously distributed among different kingdoms of life. The member enzymes catalyze the oxidization of an N-methyl amine bond of amino acids to yield unstable imine species that undergo subsequent spontaneous non-enzymatic reactions, forming an array of different products. These products range from demethylated simple species to complex alkaloids. The enzymes belonging to the sarcosine oxidase family, namely, monomeric and heterotetrameric sarcosine oxidase, l-pipecolate oxidase, N-methyltryptophan oxidase, NikD, l-proline dehydrogenase, FsqB, fructosamine oxidase and saccharopine oxidase have unique features differentiating them from other amine oxidases. This review highlights the key attributes of the sarcosine oxidase family enzymes, in terms of their substrate binding motif, type of oxidation reaction mediated and FAD regeneration, to define the boundaries of this group and demarcate these enzymes from other amine oxidase families.
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Affiliation(s)
- Majd Lahham
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria; Department of Biochemistry and Microbiology, Aljazeera Private University, Ghabagheb, Syria
| | - Shalinee Jha
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Dominic Goj
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria.
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15
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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: 65] [Impact Index Per Article: 21.7] [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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16
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Toplak M, Matthews A, Teufel R. The devil is in the details: The chemical basis and mechanistic versatility of flavoprotein monooxygenases. Arch Biochem Biophys 2020; 698:108732. [PMID: 33358998 DOI: 10.1016/j.abb.2020.108732] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/15/2020] [Accepted: 12/19/2020] [Indexed: 02/07/2023]
Abstract
The ubiquitous flavoenzymes commonly catalyze redox chemistry such as the monooxygenation of organic substrates and are both widely utilized in nature (e.g., in primary and secondary metabolism) and of significant industrial interest. In this work, we highlight the structural and mechanistic characteristics of the distinct types of flavoprotein monooxygenases (FPMOs). We thereby illustrate the chemical basis of FPMO catalysis, which enables reactions such as (aromatic) hydroxylation, epoxidation, (de)halogenation, heteroatom oxygenation, Baeyer-Villiger oxidation, α-hydroxylation of ketones, or non-oxidative carbon-hetero bond cleavage. This seemingly unmatched versatility in oxygenation chemistry results from extensive fine-tuning and regiospecific functionalization of the flavin cofactor that is tightly controlled by the surrounding protein matrix. Accordingly, FPMOs steer the formation of covalent flavin-oxygen adducts for oxygen transfer in the form of the classical flavin-C4a-(hydro)peroxide or the recently discovered N5-functionalized flavins (i.e. the flavin-N5-oxide and the flavin-N5-peroxide), while in rare cases covalent oxygen adduct formation may be foregone entirely. Finally, we speculate about hitherto undiscovered flavin-mediated oxygenation reactions and compare FPMOs to cytochrome P450 monooxygenases, before addressing open questions and challenges for the future investigation of FPMOs.
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Affiliation(s)
- Marina Toplak
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Arne Matthews
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.
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17
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Abstract
Many flavin-dependent phenolic hydroxylases (monooxygenases) have been extensively investigated. Their crystal structures and reaction mechanisms are well understood. These enzymes belong to groups A and D of the flavin-dependent monooxygenases and can be classified as single-component and two-component flavin-dependent monooxygenases. The insertion of molecular oxygen into the substrates catalyzed by these enzymes is beneficial for modifying the biological properties of phenolic compounds and their derivatives. This chapter provides an in-depth discussion of the structural features of single-component and two-component flavin-dependent phenolic hydroxylases. The reaction mechanisms of selected enzymes, including 3-hydroxy-benzoate 4-hydroxylase (PHBH) and 3-hydroxy-benzoate 6-hydroxylase as representatives of single-component enzymes and 3-hydroxyphenylacetate 4-hydroxylase (HPAH) as a representative of two-component enzymes, are discussed in detail. This chapter comprises the following four main parts: general reaction, structures, reaction mechanisms, and enzyme engineering for biocatalytic applications. Enzymes belonging to the same group catalyze similar reactions but have different unique structural features to control their reactivity to substrates and the formation and stabilization of C4a-hydroperoxyflavin. Protein engineering has been employed to improve the ability to use these enzymes to synthesize valuable compounds. A thorough understanding of the structural and mechanistic features controlling enzyme reactivity is useful for enzyme redesign and enzyme engineering for future biocatalytic applications.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand.
| | - Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand; Department of Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand
| | - Chanakan Tongsook
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
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18
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Savino S, Fraaije MW. The vast repertoire of carbohydrate oxidases: An overview. Biotechnol Adv 2020; 51:107634. [PMID: 32961251 DOI: 10.1016/j.biotechadv.2020.107634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/12/2020] [Accepted: 09/06/2020] [Indexed: 01/01/2023]
Abstract
Carbohydrates are widely abundant molecules present in a variety of forms. For their biosynthesis and modification, nature has evolved a plethora of carbohydrate-acting enzymes. Many of these enzymes are of particular interest for biotechnological applications, where they can be used as biocatalysts or biosensors. Among the enzymes catalysing conversions of carbohydrates are the carbohydrate oxidases. These oxidative enzymes belong to different structural families and use different cofactors to perform the oxidation reaction of CH-OH bonds in carbohydrates. The variety of carbohydrate oxidases available in nature reflects their specificity towards different sugars and selectivity of the oxidation site. Thanks to their properties, carbohydrate oxidases have received a lot of attention in basic and applied research, such that nowadays their role in biotechnological processes is of paramount importance. In this review we provide an overview of the available knowledge concerning the known carbohydrate oxidases. The oxidases are first classified according to their structural features. After a description on their mechanism of action, substrate acceptance and characterisation, we report on the engineering of the different carbohydrate oxidases to enhance their employment in biocatalysis and biotechnology. In the last part of the review we highlight some practical applications for which such enzymes have been exploited.
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Affiliation(s)
- Simone Savino
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, the Netherlands.
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19
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Abstract
Flavin-dependent enzymes catalyze a wide variety of biological reactions that are important for all types of living organisms. Knowledge gained from studying the chemistry and biological functions of flavins and flavin-dependent enzymes has continuously made significant contributions to the development of the fields of enzymology and metabolism from the 1970s until now. The enzymes have been applied in various applications such as use as biocatalysts in synthetic processes for the chemical and pharmaceutical industries or in the biodetoxification and bioremediation of toxic or unwanted compounds, and as biosensors or biodetection tools for quantifying various agents of interest. Many flavin-dependent enzymes are also prime targets for drug development. Based on their reaction mechanisms, they can be classified into five categories: oxidase, dehydrogenase, monooxygenase, reductase, and redox neutral flavin-dependent enzymes. In this chapter, the general properties of flavin-dependent enzymes and the nature of their chemical reactions are discussed, along with their practical applications.
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20
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Abstract
This review presents a historical outline of the research on vanillyl alcohol oxidase (VAO) from Penicillium simplicissimum, one of the canonical members of the VAO/PCMH flavoprotein family. After describing its discovery and initial biochemical characterization, we discuss the physiological role, substrate scope, and catalytic mechanism of VAO, and review its three-dimensional structure and mechanism of covalent flavinylation. We also explain how protein engineering provided a deeper insight into the role of certain amino acid residues in determining the substrate specificity and enantioselectivity of the enzyme. Finally, we summarize recent computational studies about the migration of substrates and products through the enzyme's structure and the phylogenetic distribution of VAO and related enzymes.
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Affiliation(s)
- Tom A Ewing
- Wageningen Food & Biobased Research, Wageningen University & Research, Wageningen, The Netherlands
| | - Gudrun Gygli
- Institute for Biological Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Groningen, The Netherlands
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University & Research, Wageningen, The Netherlands.
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21
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Sriwaiyaphram K, Punthong P, Sucharitakul J, Wongnate T. Structure and function relationships of sugar oxidases and their potential use in biocatalysis. Enzymes 2020; 47:193-230. [PMID: 32951824 DOI: 10.1016/bs.enz.2020.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Several sugar oxidases that catalyze the oxidation of sugars have been isolated and characterized. These enzymes can be classified as flavoenzyme due to the presence of flavin adenine dinucleotide (FAD) as a cofactor. Sugar oxidases have been proposed to be the key biocatalyst in biotransformation of carbohydrates which can potentially convert sugars to provide a pool of intermediates for synthesis of rare sugars, fine chemicals and drugs. Moreover, sugar oxidases have been applied in biosensing of various biomolecules in food industries, diagnosis of diseases and environmental pollutant detection. This review provides the discussions on general properties, current mechanistic understanding, structural determination, biocatalytic application, and biosensor integration of representative sugar oxidase enzymes, namely pyranose 2-oxidase (P2O), glucose oxidase (GO), hexose oxidase (HO), and oligosaccharide oxidase. The information regarding the relationship between structure and function of these sugar oxidases points out the key properties of this particular group of enzymes that can be modified by engineering, which had resulted in a remarkable economic importance.
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Affiliation(s)
- Kanokkan Sriwaiyaphram
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Pangrum Punthong
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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22
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Savino S, Jensen S, Terwisscha van Scheltinga A, Fraaije MW. Analysis of the structure and substrate scope of chitooligosaccharide oxidase reveals high affinity for C2-modified glucosamines. FEBS Lett 2020; 594:2819-2828. [PMID: 32491191 DOI: 10.1002/1873-3468.13854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/27/2020] [Accepted: 05/27/2020] [Indexed: 01/01/2023]
Abstract
Chitooligosaccharide oxidase (ChitO) is a fungal carbohydrate oxidase containing a bicovalently bound FAD cofactor. The enzyme is known to catalyse the oxidation of chitooligosaccharides, oligomers of N-acetylated glucosamines derived from chitin degradation. In this study, the unique substrate acceptance was explored by testing a range of N-acetyl-d-glucosamine derivatives, revealing that ChitO preferentially accepts carbohydrates with a hydrophobic group attached to C2. The enzyme also accepts streptozotocin, a natural product used to treat tumours. Elucidation of the crystal structure provides an explanation for the high affinity towards C2-decorated glucosamines: the active site has a secondary binding pocket that accommodates groups attached at C2. Docking simulations are fully in line with the observed substrate preference. This work expands the knowledge on this versatile enzyme.
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Affiliation(s)
- Simone Savino
- Molecular Enzymology Group, University of Groningen, The Netherlands
| | - Sonja Jensen
- Molecular Enzymology Group, University of Groningen, The Netherlands
| | | | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, The Netherlands
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23
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Photoinduced damage of AsLOV2 domain is accompanied by increased singlet oxygen production due to flavin dissociation. Sci Rep 2020; 10:4119. [PMID: 32139757 PMCID: PMC7058016 DOI: 10.1038/s41598-020-60861-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/13/2020] [Indexed: 01/05/2023] Open
Abstract
Flavin mononucleotide (FMN) belongs to the group of very efficient endogenous photosensitizers producing singlet oxygen, 1O2, but with limited ability to be targeted. On the other hand, in genetically-encoded photosensitizers, which can be targeted by means of various tags, the efficiency of FMN to produce 1O2 is significantly diminished due to its interactions with surrounding amino acid residues. Recently, an increase of 1O2 production yield by FMN buried in a protein matrix was achieved by a decrease of quenching of the cofactor excited states by weakening of the protein-FMN interactions while still forming a complex. Here, we suggest an alternative approach which relies on the blue light irradiation-induced dissociation of FMN to solvent. This dissociation unlocks the full capacity of FMN as 1O2 producer. Our suggestion is based on the study of an irradiation effect on two variants of the LOV2 domain from Avena sativa; wild type, AsLOV2 wt, and the variant with a replaced cysteine residue, AsLOV2 C450A. We detected irradiation-induced conformational changes as well as oxidation of several amino acids in both AsLOV2 variants. Detailed analysis of these observations indicates that irradiation-induced increase in 1O2 production is caused by a release of FMN from the protein. Moreover, an increased FMN dissociation from AsLOV2 wt in comparison with AsLOV2 C450A points to a role of C450 oxidation in repelling the cofactor from the protein.
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24
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Pitsawong W, Chenprakhon P, Dhammaraj T, Medhanavyn D, Sucharitakul J, Tongsook C, van Berkel WJH, Chaiyen P, Miller AF. Tuning of p Ka values activates substrates in flavin-dependent aromatic hydroxylases. J Biol Chem 2020; 295:3965-3981. [PMID: 32014994 DOI: 10.1074/jbc.ra119.011884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/29/2020] [Indexed: 12/31/2022] Open
Abstract
Hydroxylation of substituted phenols by flavin-dependent monooxygenases is the first step of their biotransformation in various microorganisms. The reaction is thought to proceed via electrophilic aromatic substitution, catalyzed by enzymatic deprotonation of substrate, in single-component hydroxylases that use flavin as a cofactor (group A). However, two-component hydroxylases (group D), which use reduced flavin as a co-substrate, are less amenable to spectroscopic investigation. Herein, we employed 19F NMR in conjunction with fluorinated substrate analogs to directly measure pKa values and to monitor protein events in hydroxylase active sites. We found that the single-component monooxygenase 3-hydroxybenzoate 6-hydroxylase (3HB6H) depresses the pKa of the bound substrate analog 4-fluoro-3-hydroxybenzoate (4F3HB) by 1.6 pH units, consistent with previously proposed mechanisms. 19F NMR was applied anaerobically to the two-component monooxygenase 4-hydroxyphenylacetate 3-hydroxylase (HPAH), revealing depression of the pKa of 3-fluoro-4-hydroxyphenylacetate by 2.5 pH units upon binding to the C2 component of HPAH. 19F NMR also revealed a pKa of 8.7 ± 0.05 that we attributed to an active-site residue involved in deprotonating bound substrate, and assigned to His-120 based on studies of protein variants. Thus, in both types of hydroxylases, we confirmed that binding favors the phenolate form of substrate. The 9 and 14 kJ/mol magnitudes of the effects for 3HB6H and HPAH-C2, respectively, are consistent with pKa tuning by one or more H-bonding interactions. Our implementation of 19F NMR in anaerobic samples is applicable to other two-component flavin-dependent hydroxylases and promises to expand our understanding of their catalytic mechanisms.
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Affiliation(s)
- Warintra Pitsawong
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Taweesak Dhammaraj
- Faculty of Pharmacy, Mahasarakham University, Maha Sarakham 44150, Thailand
| | - Dheeradhach Medhanavyn
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok 10300, Thailand
| | - Chanakan Tongsook
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan Valley, 555 Moo 1 Payupnai, Wangchan, Rayong 21210, Thailand
| | - Anne-Frances Miller
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
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25
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Chenprakhon P, Wongnate T, Chaiyen P. Monooxygenation of aromatic compounds by flavin-dependent monooxygenases. Protein Sci 2020; 28:8-29. [PMID: 30311986 DOI: 10.1002/pro.3525] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/08/2018] [Accepted: 10/08/2018] [Indexed: 12/12/2022]
Abstract
Many flavoenzymes catalyze hydroxylation of aromatic compounds especially phenolic compounds have been isolated and characterized. These enzymes can be classified as either single-component or two-component flavin-dependent hydroxylases (monooxygenases). The hydroxylation reactions catalyzed by the enzymes in this group are useful for modifying the biological properties of phenolic compounds. This review aims to provide an in-depth discussion of the current mechanistic understanding of representative flavin-dependent monooxygenases including 3-hydroxy-benzoate 4-hydroxylase (PHBH, a single-component hydroxylase), 3-hydroxyphenylacetate 4-hydroxylase (HPAH, a two-component hydroxylase), and other monooxygenases which catalyze reactions in addition to hydroxylation, including 2-methyl-3-hydroxypyridine-5-carboxylate oxygenase (MHPCO, a single-component enzyme that catalyzes aromatic-ring cleavage), and HadA monooxygenase (a two-component enzyme that catalyzes additional group elimination reaction). These enzymes have different unique structural features which dictate their reactivity toward various substrates and influence their ability to stabilize flavin intermediates such as C4a-hydroperoxyflavin. Understanding the key catalytic residues and the active site environments important for governing enzyme reactivity will undoubtedly facilitate future work in enzyme engineering or enzyme redesign for the development of biocatalytic methods for the synthesis of valuable compounds.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, 73170, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 14000, Thailand
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26
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Domene C, Jorgensen C, Schofield CJ. Mechanism of Molecular Oxygen Diffusion in a Hypoxia-Sensing Prolyl Hydroxylase Using Multiscale Simulation. J Am Chem Soc 2020; 142:2253-2263. [DOI: 10.1021/jacs.9b09236] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Carmen Domene
- Chemistry Research Laboratory, Mansfield Road, University of Oxford, Oxford OX1 3TA, United Kingdom
- Department of Chemistry, Britannia House, King’s College London, 7 Trinity Street, London SE1 1DB, United Kingdom
- Department of Chemistry, University of Bath, Claverton Down Bath BA2 7AY, United Kingdom
| | - Christian Jorgensen
- Department of Chemistry, Britannia House, King’s College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Mansfield Road, University of Oxford, Oxford OX1 3TA, United Kingdom
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27
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Mondal P, Huix-Rotllant M. Theoretical insights into the formation and stability of radical oxygen species in cryptochromes. Phys Chem Chem Phys 2019; 21:8874-8882. [PMID: 30977757 DOI: 10.1039/c9cp00782b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cryptochrome is a blue-light absorbing flavoprotein containing a flavin adenine dinucleotide (FAD) cofactor. FAD can accept up to two electrons and two protons, which can be subsequently transferred to substrates present in the binding pocket. It is well known that reactive oxygen species are generated when triplet molecular oxygen is present in the cavity. Here, we investigate the formation and stability of radical oxygen species in Drosophila melanogaster cryptochrome using molecular dynamics simulations and electronic structure calculations. We find that the superoxide and hydroxyl radicals in doublet spin states are stabilized in the pocket due to the attractive electrostatic interactions and hydrogen bonding with partially reduced FAD. These findings validate from a molecular dynamics perspective that [FAD˙--HO2˙] or [FADH˙-O2˙-] can be alternative radical pairs at the origin of magnetoreception.
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28
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Lyu SY, Lin KH, Yeh HW, Li YS, Huang CM, Wang YL, Shih HW, Hsu NS, Wu CJ, Li TL. The flavin mononucleotide cofactor in α-hydroxyacid oxidases exerts its electrophilic/nucleophilic duality in control of the substrate-oxidation level. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:918-929. [PMID: 31588923 PMCID: PMC6778850 DOI: 10.1107/s2059798319011938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/28/2019] [Indexed: 11/29/2022]
Abstract
Structural and enzymological explorations of p-hydroxy-mandelate oxidase and its mutants uncover an unprecedented electrophilic/nucleophilic duality for the flavin mononucleotide cofactor as well as an intramolecular disproportionation mechanism for an oxidative decarboxylation reaction. The Y128F single mutant of p-hydroxymandelate oxidase (Hmo) is capable of oxidizing mandelate to benzoate via a four-electron oxidative decarboxylation reaction. When benzoylformate (the product of the first two-electron oxidation) and hydrogen peroxide (an oxidant) were used as substrates the reaction did not proceed, suggesting that free hydrogen peroxide is not the committed oxidant in the second two-electron oxidation. How the flavin mononucleotide (FMN)-dependent four-electron oxidation reaction takes place remains elusive. Structural and biochemical explorations have shed new light on this issue. 15 high-resolution crystal structures of Hmo and its mutants liganded with or without a substrate reveal that oxidized FMN (FMNox) possesses a previously unknown electrophilic/nucleophilic duality. In the Y128F mutant the active-site perturbation ensemble facilitates the polarization of FMNox to a nucleophilic ylide, which is in a position to act on an α-ketoacid, forming an N5-acyl-FMNred dead-end adduct. In four-electron oxidation, an intramolecular disproportionation reaction via an N5-alkanol-FMNred C′α carbanion intermediate may account for the ThDP/PLP/NADPH-independent oxidative decarboxylation reaction. A synthetic 5-deaza-FMNox cofactor in combination with an α-hydroxyamide or α-ketoamide biochemically and structurally supports the proposed mechanism.
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Affiliation(s)
- Syue Yi Lyu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Kuan Hung Lin
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hsien Wei Yeh
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yi Shan Li
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chun Man Huang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yung Lin Wang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hao Wei Shih
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Ning Shian Hsu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chang Jer Wu
- Department of Food Science, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Tsung Lin Li
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
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29
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Engineering glucose oxidase for bioelectrochemical applications. Bioelectrochemistry 2019; 128:218-240. [DOI: 10.1016/j.bioelechem.2019.04.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 01/18/2023]
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Valentino H, Sobrado P. Performing anaerobic stopped-flow spectrophotometry inside of an anaerobic chamber. Methods Enzymol 2019; 620:51-88. [PMID: 31072501 DOI: 10.1016/bs.mie.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The catalytic cycle of most flavin-dependent enzymes can be divided into oxidative and reductive half-reactions. Although some enzymes are oxidized by electron carrier proteins or organic compounds, many use oxygen as the final electron acceptor. In order to properly study the reductive half-reaction of flavin-dependent enzyme that react with oxygen, as in the case of oxidases and monooxygenases, it is necessary to establish anaerobic conditions that will only allow the reduction process to be monitored. The reduced flavoenzyme can be further studied by exposing it to oxygen to monitor the oxidative half-reaction. Anaerobic chambers provide an ideal environment for performing these experiments as they reliably maintain an anaerobic atmosphere inside a large workspace. A common tool used to study flavin-dependent enzymes is the stopped-flow spectrophotometry. This chapter describes methods for performing stopped-flow experiments in an anaerobic chamber. We include information about the chamber components, setting up a stopped-flow spectrophotometer inside of a chamber, preparing anaerobic solutions, and performing experiments to measure the reductive and oxidative half-reactions of flavin-dependent monooxygenases.
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Affiliation(s)
- Hannah Valentino
- Department of Biochemistry, Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States
| | - Pablo Sobrado
- Department of Biochemistry, Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States.
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31
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Saleem-Batcha R, Teufel R. Structural methods for probing the interaction of flavoenzymes with dioxygen and its surrogates. Methods Enzymol 2019; 620:349-363. [DOI: 10.1016/bs.mie.2019.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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32
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Liu Y, Mohammadi M, Vashisth H. Diffusion network of CO in FeFe-Hydrogenase. J Chem Phys 2018; 149:204108. [PMID: 30501239 DOI: 10.1063/1.5054877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
FeFe-hydrogenase is an efficient enzyme to produce H2 under optimal conditions. However, the activity of this enzyme is highly sensitive to the presence of inhibitory gases CO and O2 that cause irreversible damage to the active site. Therefore, a detailed knowledge of the diffusion pathways of these inhibitory gases is necessary to develop strategies for designing novel enzymes that are tolerant to these gases. In this work, we studied the diffusion pathways of CO in the CpI FeFe-hydrogenase from Clostridium pasteurianum. Specifically, we used several enhanced sampling and free-energy simulation methods to reconstruct a three-dimensional free-energy surface for CO diffusion which revealed 45 free-energy minima forming an interconnected network of pathways. We discovered multiple pathways of minimal free-energy as diffusion portals for CO and found that previously suggested hydrophobic pathways are not thermodynamically favorable for CO diffusion. We also observed that the global minimum in the free-energy surface is located in the vicinity of the active-site metal cluster, the H-cluster, which suggests a high-affinity for CO near the active site. Among 19 potential residues that we propose as candidates for future mutagenesis studies, 11 residues are shared with residues that have been previously proposed to increase the tolerance of this enzyme for O2. We hypothesize that these shared candidate residues are potentially useful for designing new variants of this enzyme that are tolerant to both inhibitory gases.
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Affiliation(s)
- Yong Liu
- Department of Chemical Engineering, University of New Hampshire, 33 Academic Way, Durham, New Hampshire 03824, USA
| | - Mohammadjavad Mohammadi
- Department of Chemical Engineering, University of New Hampshire, 33 Academic Way, Durham, New Hampshire 03824, USA
| | - Harish Vashisth
- Department of Chemical Engineering, University of New Hampshire, 33 Academic Way, Durham, New Hampshire 03824, USA
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33
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Pimviriyakul P, Chaiyen P. A complete bioconversion cascade for dehalogenation and denitration by bacterial flavin-dependent enzymes. J Biol Chem 2018; 293:18525-18539. [PMID: 30282807 DOI: 10.1074/jbc.ra118.005538] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/29/2018] [Indexed: 12/17/2022] Open
Abstract
Halogenated phenol and nitrophenols are toxic compounds that are widely accumulated in the environment. Enzymes in the had operon from the bacterium Ralstonia pickettii DTP0602 have the potential for application as biocatalysts in the degradation of many of these toxic chemicals. HadA monooxygenase previously was identified as a two-component reduced FAD (FADH-)-utilizing monooxygenase with dual activities of dehalogenation and denitration. However, the partner enzymes of HadA, that is, the flavin reductase and quinone reductase that provide the FADH- for HadA and reduce quinone to hydroquinone, remain to be identified. In this report, we overexpressed and purified the flavin reductases, HadB and HadX, to investigate their functional and catalytic properties. Our results indicated that HadB is an FMN-dependent quinone reductase that converts the quinone products from HadA to hydroquinone compounds that are more stable and can be assimilated by downstream enzymes in the pathway. Transient kinetics indicated that HadB prefers NADH and menadione as the electron donor and acceptor, respectively. We found that HadX is an FAD-bound flavin reductase, which can generate FADH- for HadA to catalyze dehalogenation or denitration reactions. Thermodynamic and transient kinetic experiments revealed that HadX prefers to bind FAD over FADH- and that HadX can transfer FADH- from HadX to HadA via free diffusion. Moreover, HadX rapidly catalyzed NADH-mediated reduction of flavin and provided the FADH- for a monooxygenase of a different system. Combination of all three flavin-dependent enzymes, i.e. HadA/HadB/HadX, reconstituted an effective dehalogenation and denitration cascade, which may be useful for future bioremediation applications.
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Affiliation(s)
- Panu Pimviriyakul
- From the School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210 and.,the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 14000, Thailand
| | - Pimchai Chaiyen
- From the School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210 and
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34
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Zhang W, Hollmann F. Nonconventional regeneration of redox enzymes - a practical approach for organic synthesis? Chem Commun (Camb) 2018; 54:7281-7289. [PMID: 29714371 DOI: 10.1039/c8cc02219d] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxidoreductases have become useful tools in the hands of chemists to perform selective and mild oxidation and reduction reactions. Instead of mimicking native catalytic cycles, generally involving costly and unstable nicotinamide cofactors, more direct, NAD(P)-independent methodologies are being developed. The promise of these approaches not only lies with simpler and cheaper reaction schemes but also with higher selectivity as compared to whole cell approaches and their mimics.
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Affiliation(s)
- Wuyuan Zhang
- Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands.
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35
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Enzymatic control of dioxygen binding and functionalization of the flavin cofactor. Proc Natl Acad Sci U S A 2018; 115:4909-4914. [PMID: 29686059 DOI: 10.1073/pnas.1801189115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reactions of enzymes and cofactors with gaseous molecules such as dioxygen (O2) are challenging to study and remain among the most contentious subjects in biochemistry. To date, it is largely enigmatic how enzymes control and fine-tune their reactions with O2, as exemplified by the ubiquitous flavin-dependent enzymes that commonly facilitate redox chemistry such as the oxygenation of organic substrates. Here we employ O2-pressurized X-ray crystallography and quantum mechanical calculations to reveal how the precise positioning of O2 within a flavoenzyme's active site enables the regiospecific formation of a covalent flavin-oxygen adduct and oxygenating species (i.e., the flavin-N5-oxide) by mimicking a critical transition state. This study unambiguously demonstrates how enzymes may control the O2 functionalization of an organic cofactor as prerequisite for oxidative catalysis. Our work thus illustrates how O2 reactivity can be harnessed in an enzymatic environment and provides crucial knowledge for future rational design of O2-reactive enzymes.
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36
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Im D, Matsui D, Arakawa T, Isobe K, Asano Y, Fushinobu S. Ligand complex structures of l-amino acid oxidase/monooxygenase from Pseudomonas sp. AIU 813 and its conformational change. FEBS Open Bio 2018; 8:314-324. [PMID: 29511608 PMCID: PMC5832979 DOI: 10.1002/2211-5463.12387] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/26/2017] [Accepted: 01/16/2018] [Indexed: 11/06/2022] Open
Abstract
l-Amino acid oxidase/monooxygenase from Pseudomonas sp. AIU 813 (l-AAO/MOG) catalyzes both the oxidative deamination and oxidative decarboxylation of the α-group of l-Lys to produce a keto acid and amide, respectively. l-AAO/MOG exhibits limited specificity for l-amino acid substrates with a basic side chain. We previously determined its ligand-free crystal structure and identified a key residue for maintaining the dual activities. Here, we determined the structures of l-AAO/MOG complexed with l-Lys, l-ornithine, and l-Arg and revealed its substrate recognition. Asp238 is located at the ceiling of a long hydrophobic pocket and forms a strong interaction with the terminal, positively charged group of the substrates. A mutational analysis on the D238A mutant indicated that the interaction is critical for substrate binding but not for catalytic control between the oxidase/monooxygenase activities. The catalytic activities of the D238E mutant unexpectedly increased, while the D238F mutant exhibited altered substrate specificity to long hydrophobic substrates. In the ligand-free structure, there are two channels connecting the active site and solvent, and a short region located at the dimer interface is disordered. In the l-Lys complex structure, a loop region is displaced to plug the channels. Moreover, the disordered region in the ligand-free structure forms a short helix in the substrate complex structures and creates the second binding site for the substrate. It is assumed that the amino acid substrate enters the active site of l-AAO/MOG through this route. Database The atomic coordinates and structure factors (codes 5YB6, 5YB7, and 5YB8) have been deposited in the Protein Data Bank (http://wwpdb.org/). EC numbers 1.4.3.2 (l-amino acid oxidase), 1.13.12.2 (lysine 2-monooxygenase).
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Affiliation(s)
- Dohyun Im
- Department of Biotechnology The University of Tokyo Japan.,Present address: Department of Cell Biology Graduate School of Medicine Kyoto University Yoshidakonoe-cho, Sakyo-ku Kyoto 606-8501 Japan
| | - Daisuke Matsui
- Department of Biotechnology Biotechnology Research Center Toyama Prefectural University Imizu Japan.,Asano Active Enzyme Molecule Project ERATOJS TImizu Japan
| | | | - Kimiyasu Isobe
- Asano Active Enzyme Molecule Project ERATOJS TImizu Japan
| | - Yasuhisa Asano
- Department of Biotechnology Biotechnology Research Center Toyama Prefectural University Imizu Japan.,Asano Active Enzyme Molecule Project ERATOJS TImizu Japan
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37
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El Hage K, Mondal P, Meuwly M. Free energy simulations for protein ligand binding and stability. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2017.1416115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Krystel El Hage
- Department of Chemistry, University of Basel , Basel, Switzerland
| | - Padmabati Mondal
- Department of Chemistry, University of Basel , Basel, Switzerland
| | - Markus Meuwly
- Department of Chemistry, University of Basel , Basel, Switzerland
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38
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Romero E, Gómez Castellanos JR, Gadda G, Fraaije MW, Mattevi A. Same Substrate, Many Reactions: Oxygen Activation in Flavoenzymes. Chem Rev 2018; 118:1742-1769. [DOI: 10.1021/acs.chemrev.7b00650] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Elvira Romero
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - J. Rubén Gómez Castellanos
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Giovanni Gadda
- Departments of Chemistry and Biology, Center for Diagnostics and Therapeutics, and Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia 30302-3965, United States
| | - Marco W. Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Andrea Mattevi
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
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39
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Molecular Basis for Converting (2S)-Methylsuccinyl-CoA Dehydrogenase into an Oxidase. Molecules 2017; 23:molecules23010068. [PMID: 29283425 PMCID: PMC6017585 DOI: 10.3390/molecules23010068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/18/2017] [Accepted: 12/21/2017] [Indexed: 11/17/2022] Open
Abstract
Although flavoenzymes have been studied in detail, the molecular basis of their dioxygen reactivity is only partially understood. The members of the flavin adenosine dinucleotide (FAD)-dependent acyl-CoA dehydrogenase and acyl-CoA oxidase families catalyze similar reactions and share common structural features. However, both enzyme families feature opposing reaction specificities in respect to dioxygen. Dehydrogenases react with electron transfer flavoproteins as terminal electron acceptors and do not show a considerable reactivity with dioxygen, whereas dioxygen serves as a bona fide substrate for oxidases. We recently engineered (2S)-methylsuccinyl-CoA dehydrogenase towards oxidase activity by rational mutagenesis. Here we characterized the (2S)-methylsuccinyl-CoA dehydrogenase wild-type, as well as the engineered (2S)-methylsuccinyl-CoA oxidase, in detail. Using stopped-flow UV-spectroscopy and liquid chromatography-mass spectrometry (LC-MS) based assays, we explain the molecular base for dioxygen reactivity in the engineered oxidase and show that the increased oxidase function of the engineered enzyme comes at a decreased dehydrogenase activity. Our findings add to the common notion that an increased activity for a specific substrate is achieved at the expense of reaction promiscuity and provide guidelines for rational engineering efforts of acyl-CoA dehydrogenases and oxidases.
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40
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Gygli G, Lucas MF, Guallar V, van Berkel WJH. The ins and outs of vanillyl alcohol oxidase: Identification of ligand migration paths. PLoS Comput Biol 2017; 13:e1005787. [PMID: 28985219 PMCID: PMC5646868 DOI: 10.1371/journal.pcbi.1005787] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/18/2017] [Accepted: 09/21/2017] [Indexed: 01/03/2023] Open
Abstract
Vanillyl alcohol oxidase (VAO) is a homo-octameric flavoenzyme belonging to the VAO/PCMH family. Each VAO subunit consists of two domains, the FAD-binding and the cap domain. VAO catalyses, among other reactions, the two-step conversion of p-creosol (2-methoxy-4-methylphenol) to vanillin (4-hydroxy-3-methoxybenzaldehyde). To elucidate how different ligands enter and exit the secluded active site, Monte Carlo based simulations have been performed. One entry/exit path via the subunit interface and two additional exit paths have been identified for phenolic ligands, all leading to the si side of FAD. We argue that the entry/exit path is the most probable route for these ligands. A fourth path leading to the re side of FAD has been found for the co-ligands dioxygen and hydrogen peroxide. Based on binding energies and on the behaviour of ligands in these four paths, we propose a sequence of events for ligand and co-ligand migration during catalysis. We have also identified two residues, His466 and Tyr503, which could act as concierges of the active site for phenolic ligands, as well as two other residues, Tyr51 and Tyr408, which could act as a gateway to the re side of FAD for dioxygen. Most of the residues in the four paths are also present in VAO’s closest relatives, eugenol oxidase and p-cresol methylhydroxylase. Key path residues show movements in our simulations that correspond well to conformations observed in crystal structures of these enzymes. Preservation of other path residues can be linked to the electron acceptor specificity and oligomerisation state of the three enzymes. This study is the first comprehensive overview of ligand and co-ligand migration in a member of the VAO/PCMH family, and provides a proof of concept for the use of an unbiased method to sample this process. Enzymes are bionanomachines, which speed up chemical reactions in organisms. To understand how they achieve that, we need to study their mechanisms. Computational enzymology can show us what happens in the enzyme’s active site during a reaction. But molecules need first to reach the active site before a reaction can start. The process of substrate entry and product exit to the active site is often neglected when studying enzymes. However, these two events are of fundamental importance to the proper functioning of any enzyme. We are interested in these dynamic processes to complete our understanding of the mode of action of enzymes. In our work, we have studied substrate and product migration in vanillyl alcohol oxidase. This enzyme can produce the flavour vanillin and enantiopure alcohols, but also catalyses other reactions. The named products are of interest to the flavour- and fine-chemical industries.
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Affiliation(s)
- Gudrun Gygli
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, WE Wageningen, The Netherlands
| | - Maria Fátima Lucas
- Joint BSC-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona, Spain
| | - Victor Guallar
- Joint BSC-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Jordi Girona 29, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, Barcelona, Spain
| | - Willem J. H. van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, WE Wageningen, The Netherlands
- * E-mail:
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41
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Ewing TA, Fraaije MW, Mattevi A, van Berkel WJ. The VAO/PCMH flavoprotein family. Arch Biochem Biophys 2017; 632:104-117. [DOI: 10.1016/j.abb.2017.06.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 01/15/2023]
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Westberg M, Bregnhøj M, Etzerodt M, Ogilby PR. No Photon Wasted: An Efficient and Selective Singlet Oxygen Photosensitizing Protein. J Phys Chem B 2017; 121:9366-9371. [PMID: 28892628 DOI: 10.1021/acs.jpcb.7b07831] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Optogenetics has been, and will continue to be, a boon to mechanistic studies of cellular processes. Genetically encodable proteins that sensitize the production of reactive oxygen species (ROS) are expected to play an increasingly important role, particularly in elucidating mechanisms of temporally and spatially dependent cell signaling. However, a substantial challenge in developing such photosensitizing proteins has been to funnel the optical excitation energy into the initial selective production of only one ROS. Singlet molecular oxygen, O2(a1Δg), is a ROS known to have a wide range of effects on cell function. Nevertheless, mechanistic details of singlet oxygen's behavior in a cell are lacking. On the basis of the rational optimization of a LOV-derived flavoprotein, we now report the development and photophysical characterization of a protein-encased photosensitizer that efficiently and selectively produces singlet oxygen at the expense of other ROS, especially ROS that derive from photoinduced electron transfer reactions. These results set the stage for a plethora of new experiments to elucidate ROS-mediated events in cells.
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Affiliation(s)
- Michael Westberg
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Mikkel Bregnhøj
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Michael Etzerodt
- Department of Molecular Biology and Genetics, Aarhus University , DK-8000 Aarhus, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
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43
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Tremey E, Stines-Chaumeil C, Gounel S, Mano N. Designing an O2
-Insensitive Glucose Oxidase for Improved Electrochemical Applications. ChemElectroChem 2017. [DOI: 10.1002/celc.201700646] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Emilie Tremey
- CNRS, CRPP - UPR 8641; 115 Avenue du Docteur Schweitzer 33600 Pessac France
- Univ Bordeaux; 146 rue Léo Saignat 33076 Bordeaux Cedex France
| | - Claire Stines-Chaumeil
- CNRS, CRPP - UPR 8641; 115 Avenue du Docteur Schweitzer 33600 Pessac France
- Univ Bordeaux; 146 rue Léo Saignat 33076 Bordeaux Cedex France
| | - Sébastien Gounel
- CNRS, CRPP - UPR 8641; 115 Avenue du Docteur Schweitzer 33600 Pessac France
- Univ Bordeaux; 146 rue Léo Saignat 33076 Bordeaux Cedex France
| | - Nicolas Mano
- CNRS, CRPP - UPR 8641; 115 Avenue du Docteur Schweitzer 33600 Pessac France
- Univ Bordeaux; 146 rue Léo Saignat 33076 Bordeaux Cedex France
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44
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Mi L, Yu J, He F, Jiang L, Wu Y, Yang L, Han X, Li Y, Liu A, Wei W, Zhang Y, Tian Y, Liu S, Jiang L. Boosting Gas Involved Reactions at Nanochannel Reactor with Joint Gas–Solid–Liquid Interfaces and Controlled Wettability. J Am Chem Soc 2017; 139:10441-10446. [DOI: 10.1021/jacs.7b05249] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Li Mi
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Jiachao Yu
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Fei He
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Ling Jiang
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Yafeng Wu
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Lijun Yang
- Key
Laboratory of Bioinspired Smart Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiaofeng Han
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Ying Li
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Anran Liu
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Wei Wei
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Yuanjian Zhang
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Ye Tian
- Beijing
National Laboratory for Molecular Sciences (BNLMS), Key Laboratory
of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Songqin Liu
- Key
Laboratory of Environmental Medicine Engineering, Ministry of Education,
Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and
Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China
| | - Lei Jiang
- Key
Laboratory of Bioinspired Smart Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
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45
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Abstract
Cysteine thiols are among the most reactive functional groups in proteins, and their pairing in disulfide linkages is a common post-translational modification in proteins entering the secretory pathway. This modest amino acid alteration, the mere removal of a pair of hydrogen atoms from juxtaposed cysteine residues, contrasts with the substantial changes that characterize most other post-translational reactions. However, the wide variety of proteins that contain disulfides, the profound impact of cross-linking on the behavior of the protein polymer, the numerous and diverse players in intracellular pathways for disulfide formation, and the distinct biological settings in which disulfide bond formation can take place belie the simplicity of the process. Here we lay the groundwork for appreciating the mechanisms and consequences of disulfide bond formation in vivo by reviewing chemical principles underlying cysteine pairing and oxidation. We then show how enzymes tune redox-active cofactors and recruit oxidants to improve the specificity and efficiency of disulfide formation. Finally, we discuss disulfide bond formation in a cellular context and identify important principles that contribute to productive thiol oxidation in complex, crowded, dynamic environments.
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Affiliation(s)
- Deborah Fass
- Department of Structural Biology, Weizmann Institute of Science , Rehovot 7610001, Israel
| | - Colin Thorpe
- Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States
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46
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The family of berberine bridge enzyme-like enzymes: A treasure-trove of oxidative reactions. Arch Biochem Biophys 2017; 632:88-103. [PMID: 28676375 DOI: 10.1016/j.abb.2017.06.023] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 12/18/2022]
Abstract
Biological oxidations form the basis of life on earth by utilizing organic compounds as electron donors to drive the generation of metabolic energy carriers, such as ATP. Oxidative reactions are also important for the biosynthesis of complex compounds, i.e. natural products such as alkaloids that provide vital benefits for organisms in all kingdoms of life. The vitamin B2-derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) enable an astonishingly diverse array of oxidative reactions that is based on the versatility of the redox-active isoalloxazine ring. The family of FAD-linked oxidases can be divided into subgroups depending on specific sequence features in an otherwise very similar structural context. The sub-family of berberine bridge enzyme (BBE)-like enzymes has recently attracted a lot of attention due to the challenging chemistry catalyzed by its members and the unique and unusual bi-covalent attachment of the FAD cofactor. This family is the focus of the present review highlighting recent advancements into the structural and functional aspects of members from bacteria, fungi and plants. In view of the unprecedented reaction catalyzed by the family's namesake, BBE from the California poppy, recent studies have provided further insights into nature's treasure chest of oxidative reactions.
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47
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Waldman AJ, Ng TL, Wang P, Balskus EP. Heteroatom-Heteroatom Bond Formation in Natural Product Biosynthesis. Chem Rev 2017; 117:5784-5863. [PMID: 28375000 PMCID: PMC5534343 DOI: 10.1021/acs.chemrev.6b00621] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Natural products that contain functional groups with heteroatom-heteroatom linkages (X-X, where X = N, O, S, and P) are a small yet intriguing group of metabolites. The reactivity and diversity of these structural motifs has captured the interest of synthetic and biological chemists alike. Functional groups containing X-X bonds are found in all major classes of natural products and often impart significant biological activity. This review presents our current understanding of the biosynthetic logic and enzymatic chemistry involved in the construction of X-X bond containing functional groups within natural products. Elucidating and characterizing biosynthetic pathways that generate X-X bonds could both provide tools for biocatalysis and synthetic biology, as well as guide efforts to uncover new natural products containing these structural features.
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Affiliation(s)
- Abraham J. Waldman
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Tai L. Ng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Peng Wang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
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48
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Chenprakhon P, Dhammaraj T, Chantiwas R, Chaiyen P. Hydroxylation of 4-hydroxyphenylethylamine derivatives by R263 variants of the oxygenase component of p -hydroxyphenylacetate-3-hydroxylase. Arch Biochem Biophys 2017; 620:1-11. [DOI: 10.1016/j.abb.2017.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 11/29/2022]
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49
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Westberg M, Bregnhøj M, Etzerodt M, Ogilby PR. Temperature Sensitive Singlet Oxygen Photosensitization by LOV-Derived Fluorescent Flavoproteins. J Phys Chem B 2017; 121:2561-2574. [PMID: 28257211 DOI: 10.1021/acs.jpcb.7b00561] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Optogenetic sensitizers that selectively produce a given reactive oxygen species (ROS) constitute a promising tool for studying cell signaling processes with high levels of spatiotemporal control. However, to harness the full potential of this tool for live cell studies, the photophysics of currently available systems need to be explored further and optimized. Of particular interest in this regard, are the flavoproteins miniSOG and SOPP, both of which (1) contain the chromophore flavin mononucleotide, FMN, in a LOV-derived protein enclosure, and (2) photosensitize the production of singlet oxygen, O2(a1Δg). Here we present an extensive experimental study of the singlet and triplet state photophysics of FMN in SOPP and miniSOG over a physiologically relevant temperature range. Although changes in temperature only affect the singlet excited state photophysics slightly, the processes that influence the deactivation of the triplet excited state are more sensitive to temperature. Most notably, for both proteins, the rate constant for quenching of 3FMN by ground state oxygen, O2(X3Σg-), increases ∼10-fold upon increasing the temperature from 10 to 43 °C, while the oxygen-independent channels of triplet state deactivation are less affected. As a consequence, this increase in temperature results in higher yields of O2(a1Δg) formation for both SOPP and miniSOG. We also show that the quantum yields of O2(a1Δg) production by both miniSOG and SOPP are mainly limited by the fraction of FMN triplet states quenched by O2(X3Σg-). The results presented herein provide a much-needed quantitative framework that will facilitate the future development of optogenetic ROS sensitizers.
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Affiliation(s)
- Michael Westberg
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Mikkel Bregnhøj
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Michael Etzerodt
- Department of Molecular Biology and Genetics, Aarhus University , DK-8000 Aarhus, Denmark
| | - Peter R Ogilby
- Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
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50
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Pimviriyakul P, Thotsaporn K, Sucharitakul J, Chaiyen P. Kinetic Mechanism of the Dechlorinating Flavin-dependent Monooxygenase HadA. J Biol Chem 2017; 292:4818-4832. [PMID: 28159841 DOI: 10.1074/jbc.m116.774448] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 01/30/2017] [Indexed: 01/26/2023] Open
Abstract
The accumulation of chlorophenols (CPs) in the environment, due to their wide use as agrochemicals, has become a serious environmental problem. These organic halides can be degraded by aerobic microorganisms, where the initial steps of various biodegradation pathways include an oxidative dechlorinating process in which chloride is replaced by a hydroxyl substituent. Harnessing these dechlorinating processes could provide an opportunity for environmental remediation, but detailed catalytic mechanisms for these enzymes are not yet known. To close this gap, we now report transient kinetics and product analysis of the dechlorinating flavin-dependent monooxygenase, HadA, from the aerobic organism Ralstonia pickettii DTP0602, identifying several mechanistic properties that differ from other enzymes in the same class. We first overexpressed and purified HadA to homogeneity. Analyses of the products from single and multiple turnover reactions demonstrated that HadA prefers 4-CP and 2-CP over CPs with multiple substituents. Stopped-flow and rapid-quench flow experiments of HadA with 4-CP show the involvement of specific intermediates (C4a-hydroperoxy-FAD and C4a-hydroxy-FAD) in the reaction, define rate constants and the order of substrate binding, and demonstrate that the hydroxylation step occurs prior to chloride elimination. The data also identify the non-productive and productive paths of the HadA reactions and demonstrate that product formation is the rate-limiting step. This is the first elucidation of the kinetic mechanism of a two-component flavin-dependent monooxygenase that can catalyze oxidative dechlorination of various CPs, and as such it will serve as the basis for future investigation of enzyme variants that will be useful for applications in detoxifying chemicals hazardous to human health.
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Affiliation(s)
- Panu Pimviriyakul
- From the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400 and
| | - Kittisak Thotsaporn
- the Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok 10300, Thailand
| | - Jeerus Sucharitakul
- the Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok 10300, Thailand
| | - Pimchai Chaiyen
- From the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400 and
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