1
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Johnson S, Li H, Valentino H, Sobrado P. Mechanism of Nitrone Formation by a Flavin-Dependent Monooxygenase. Biochemistry 2024; 63:1445-1459. [PMID: 38779817 PMCID: PMC11154958 DOI: 10.1021/acs.biochem.3c00656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
OxaD is a flavin-dependent monooxygenase (FMO) responsible for catalyzing the oxidation of an indole nitrogen atom, resulting in the formation of a nitrone. Nitrones serve as versatile intermediates in complex syntheses, including challenging reactions like cycloadditions. Traditional organic synthesis methods often yield limited results and involve environmentally harmful chemicals. Therefore, the enzymatic synthesis of nitrone-containing compounds holds promise for more sustainable industrial processes. In this study, we explored the catalytic mechanism of OxaD using a combination of steady-state and rapid-reaction kinetics, site-directed mutagenesis, spectroscopy, and structural modeling. Our investigations showed that OxaD catalyzes two oxidations of the indole nitrogen of roquefortine C, ultimately yielding roquefortine L. The reductive-half reaction analysis indicated that OxaD rapidly undergoes reduction and follows a "cautious" flavin reduction mechanism by requiring substrate binding before reduction can take place. This characteristic places OxaD in class A of the FMO family, a classification supported by a structural model featuring a single Rossmann nucleotide binding domain and a glutathione reductase fold. Furthermore, our spectroscopic analysis unveiled both enzyme-substrate and enzyme-intermediate complexes. Our analysis of the oxidative-half reaction suggests that the flavin dehydration step is the slow step in the catalytic cycle. Finally, through mutagenesis of the conserved D63 residue, we demonstrated its role in flavin motion and product oxygenation. Based on our findings, we propose a catalytic mechanism for OxaD and provide insights into the active site architecture within class A FMOs.
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Affiliation(s)
- Sydney
B. Johnson
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hao Li
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hannah Valentino
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Pablo Sobrado
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
- Center
of Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United
States
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2
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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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3
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Phintha A, Chaiyen P. Unifying and versatile features of flavin-dependent monooxygenases: Diverse catalysis by a common C4a-(hydro)peroxyflavin. J Biol Chem 2023; 299:105413. [PMID: 37918809 PMCID: PMC10696468 DOI: 10.1016/j.jbc.2023.105413] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/18/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023] Open
Abstract
Flavin-dependent monooxygenases (FDMOs) are known for their remarkable versatility and for their crucial roles in various biological processes and applications. Extensive research has been conducted to explore the structural and functional relationships of FDMOs. The majority of reported FDMOs utilize C4a-(hydro)peroxyflavin as a reactive intermediate to incorporate an oxygen atom into a wide range of compounds. This review discusses and analyzes recent advancements in our understanding of the structural and mechanistic features governing the enzyme functions. State-of-the-art discoveries related to common and distinct structural properties governing the catalytic versatility of the C4a-(hydro)peroxyflavin intermediate in selected FDMOs are discussed. Specifically, mechanisms of hydroxylation, dehalogenation, halogenation, and light-emitting reactions by FDMOs are highlighted. We also provide new analysis based on the structural and mechanistic features of these enzymes to gain insights into how the same intermediate can be harnessed to perform a wide variety of reactions. Challenging questions to obtain further breakthroughs in the understanding of FDMOs are also proposed.
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Affiliation(s)
- Aisaraphon Phintha
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand.
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4
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Pimviriyakul P, Chaiyen P. Formation and stabilization of C4a-hydroperoxy-FAD by the Arg/Asn pair in HadA monooxygenase. FEBS J 2023; 290:176-195. [PMID: 35942637 DOI: 10.1111/febs.16591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/25/2022] [Accepted: 08/08/2022] [Indexed: 01/14/2023]
Abstract
HadA monooxygenase catalyses the detoxification of halogenated phenols and nitrophenols via dehalogenation and denitration respectively. C4a-hydroperoxy-FAD is a key reactive intermediate wherein its formation, protonation and stabilization reflect enzyme efficiency. Herein, transient kinetics, site-directed mutagenesis and pH-dependent behaviours of HadA reaction were employed to identify key features stabilizing C4a-adducts in HadA. The formation of C4a-hydroperoxy-FAD is pH independent, whereas its decay and protonation of distal oxygen are associated with pKa values of 8.5 and 8.4 respectively. These values are correlated with product formation within a pH range of 7.6-9.1, indicating the importance of adduct stabilization to enzymatic efficiency. We identified Arg101 as a key residue for reduced FAD (FADH- ) binding and C4a-hydroperoxy-FAD formation due to the loss of these abilities as well as enzyme activity in HadAR101A and HadAR101Q . Mutations of the neighbouring Asn447 do not affect the rate of C4a-hydroperoxy-FAD formation; however, they impair FADH- binding. The disruption of Arg101/Asn447 hydrogen bond networking in HadAN447A increases the pKa value of C4a-hydroperoxy-FAD decay to 9.5; however, this pKa was not altered in HadAN447D (pKa of 8.5). Thus, Arg101/Asn447 pair should provide important interactions for FADH- binding and maintain the pKa associated with H2 O2 elimination from C4a-hydroperoxy-FAD in HadA. In the presence of substrate, the formation of C4a-hydroxy-FAD at the hydroxylation step is pH insensitive, and it dehydrates to form the oxidized FAD with pKa of 7.9. This structural feature might help elucidate how the reactive intermediate was stabilized in other flavin-dependent monooxygenases.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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5
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Pimviriyakul P, Jaruwat A, Chitnumsub P, Chaiyen P. Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking. J Biol Chem 2021; 297:100952. [PMID: 34252455 PMCID: PMC8342789 DOI: 10.1016/j.jbc.2021.100952] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 12/20/2022] Open
Abstract
HadA is a flavin-dependent monooxygenase catalyzing hydroxylation plus dehalogenation/denitration, which is useful for biodetoxification and biodetection. In this study, the X-ray structure of wild-type HadA (HadAWT) co-complexed with reduced FAD (FADH–) and 4-nitrophenol (4NP) (HadAWT−FADH–−4NP) was solved at 2.3-Å resolution, providing the first full package (with flavin and substrate bound) structure of a monooxygenase of this type. Residues Arg101, Gln158, Arg161, Thr193, Asp254, Arg233, and Arg439 constitute a flavin-binding pocket, whereas the 4NP-binding pocket contains the aromatic side chain of Phe206, which provides π-π stacking and also is a part of the hydrophobic pocket formed by Phe155, Phe286, Thr449, and Leu457. Based on site-directed mutagenesis and stopped-flow experiments, Thr193, Asp254, and His290 are important for C4a-hydroperoxyflavin formation with His290, also serving as a catalytic base for hydroxylation. We also identified a novel structural motif of quadruple π-stacking (π-π-π-π) provided by two 4NP and two Phe441 from two subunits. This motif promotes 4NP binding in a nonproductive dead-end complex, which prevents C4a-hydroperoxy-FAD formation when HadA is premixed with aromatic substrates. We also solved the structure of the HadAPhe441Val−FADH–−4NP complex at 2.3-Å resolution. Although 4NP can still bind to this variant, the quadruple π-stacking motif was disrupted. All HadAPhe441 variants lack substrate inhibition behavior, confirming that quadruple π-stacking is a main cause of dead-end complex formation. Moreover, the activities of these HadAPhe441 variants were improved by ⁓20%, suggesting that insights gained from the flavin-dependent monooxygenases illustrated here should be useful for future improvement of HadA’s biocatalytic applications.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Aritsara Jaruwat
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand.
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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6
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Reis RAG, Li H, Johnson M, Sobrado P. New frontiers in flavin-dependent monooxygenases. Arch Biochem Biophys 2021; 699:108765. [PMID: 33460580 DOI: 10.1016/j.abb.2021.108765] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/15/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of redox reactions in important biological processes and are responsible for the synthesis of highly complex natural products. Although much has been learned about FMO chemistry in the last ~80 years of research, several aspects of the reactions catalyzed by these enzymes remain unknown. In this review, we summarize recent advancements in the flavin-dependent monooxygenase field including aspects of flavin dynamics, formation and stabilization of reactive species, and the hydroxylation mechanism. Novel catalysis of flavin-dependent N-oxidases involving consecutive oxidations of amines to generate oximes or nitrones is presented and the biological relevance of the products is discussed. In addition, the activity of some FMOs have been shown to be essential for the virulence of several human pathogens. We also discuss the biomedical relevance of FMOs in antibiotic resistance and the efforts to identify inhibitors against some members of this important and growing family enzymes.
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Affiliation(s)
| | - Hao Li
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Maxim Johnson
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Pablo Sobrado
- Department of Biochemistry, Blacksburg, VA, 24061, USA; Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
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7
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Tinikul R, Lawan N, Akeratchatapan N, Pimviriyakul P, Chinantuya W, Suadee C, Sucharitakul J, Chenprakhon P, Ballou DP, Entsch B, Chaiyen P. Protonation status and control mechanism of flavin-oxygen intermediates in the reaction of bacterial luciferase. FEBS J 2020; 288:3246-3260. [PMID: 33289305 DOI: 10.1111/febs.15653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 11/15/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022]
Abstract
Bacterial luciferase catalyzes a bioluminescent reaction by oxidizing long-chain aldehydes to acids using reduced FMN and oxygen as co-substrates. Although a flavin C4a-peroxide anion is postulated to be the intermediate reacting with aldehyde prior to light liberation, no clear identification of the protonation status of this intermediate has been reported. Here, transient kinetics, pH variation, and site-directed mutagenesis were employed to probe the protonation state of the flavin C4a-hydroperoxide in bacterial luciferase. The first observed intermediate, with a λmax of 385 nm, transformed to an intermediate with a λmax of 375 nm. Spectra of the first observed intermediate were pH-dependent, with a λmax of 385 nm at pH < 8.5 and 375 at pH > 9, correlating with a pKa of 7.7-8.1. These data are consistent with the first observed flavin C4a intermediate at pH < 8.5 being the protonated flavin C4a-hydroperoxide, which loses a proton to become an active flavin C4a-peroxide. Stopped-flow studies of His44Ala, His44Asp, and His44Asn variants showed only a single intermediate with a λmax of 385 nm at all pH values, and none of these variants generate light. These data indicate that His44 variants only form a flavin C4a-hydroperoxide, but not an active flavin C4a-peroxide, indicating an essential role for His44 in deprotonating the flavin C4a-hydroperoxide and initiating chemical catalysis. We also investigated the function of the adjacent His45; stopped-flow data and molecular dynamics simulations identify the role of this residue in binding reduced FMN.
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Affiliation(s)
- Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of Science, Chiangmai University, Thailand
| | - Nattanon Akeratchatapan
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Wachirawit Chinantuya
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Chutintorn Suadee
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand
| | - David P Ballou
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Barrie Entsch
- School of Science and Technology, University of New England, Armidale, NSW, Australia
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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8
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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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9
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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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10
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Lisitsa AE, Sukovatyi LA, Kratasyuk VA, Nemtseva EV. Viscous Media Slow Down the Decay of the Key Intermediate in Bacterial Bioluminescent Reaction. DOKL BIOCHEM BIOPHYS 2020; 492:162-165. [PMID: 32632596 DOI: 10.1134/s1607672920020106] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 11/23/2022]
Abstract
The effects of medium viscosity on the decay rate of the 4a-hydroperoxyflavin intermediate of the bioluminescent reaction was investigated. It was found that at low concentrations of glycerol or sucrose (viscosity 1.1-1.3 cP) the decay rate rises, whereas a further increase in viscosity to 6.2 cP leads to a decrease in the decay rate following a power function with an exponent of 0.82-0.84. Using molecular dynamics methods, it was shown that the presence of glycerol and sucrose molecules causes a change in the mobility of the amino acid residues in the active center of luciferase, particularly those responsible for binding of flavin. The results obtained are indicative of two opposite effects of viscous media with glycerol and sucrose: (1) destabilization of 4a-hydroperoxyflavin due to a change in the structural and dynamic properties of the protein and (2) stabilization of this intermediate by the decrease in the diffusion rate of its decay products.
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Affiliation(s)
- A E Lisitsa
- Siberian Federal University, Krasnoyarsk, Russia.
| | | | - V A Kratasyuk
- Siberian Federal University, Krasnoyarsk, Russia.,Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, Russia
| | - E V Nemtseva
- Siberian Federal University, Krasnoyarsk, Russia.,Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, Russia
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11
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Trisrivirat D, Lawan N, Chenprakhon P, Matsui D, Asano Y, Chaiyen P. Mechanistic insights into the dual activities of the single active site of l-lysine oxidase/monooxygenase from Pseudomonas sp. AIU 813. J Biol Chem 2020; 295:11246-11261. [PMID: 32527725 DOI: 10.1074/jbc.ra120.014055] [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: 04/24/2020] [Revised: 06/10/2020] [Indexed: 12/19/2022] Open
Abstract
l-Lysine oxidase/monooxygenase (l-LOX/MOG) from Pseudomonas sp. AIU 813 catalyzes the mixed bioconversion of l-amino acids, particularly l-lysine, yielding an amide and carbon dioxide by an oxidative decarboxylation (i.e. apparent monooxygenation), as well as oxidative deamination (hydrolysis of oxidized product), resulting in α-keto acid, hydrogen peroxide (H2O2), and ammonia. Here, using high-resolution MS and monitoring transient reaction kinetics with stopped-flow spectrophotometry, we identified the products from the reactions of l-lysine and l-ornithine, indicating that besides decarboxylating imino acids (i.e. 5-aminopentanamide from l-lysine), l-LOX/MOG also decarboxylates keto acids (5-aminopentanoic acid from l-lysine and 4-aminobutanoic acid from l-ornithine). The reaction of reduced enzyme and oxygen generated an imino acid and H2O2, with no detectable C4a-hydroperoxyflavin. Single-turnover reactions in which l-LOX/MOG was first reduced by l-lysine to form imino acid before mixing with various compounds revealed that under anaerobic conditions, only hydrolysis products are present. Similar results were obtained upon H2O2 addition after enzyme denaturation. H2O2 addition to active l-LOX/MOG resulted in formation of more 5-aminopentanoic acid, but not 5-aminopentamide, suggesting that H2O2 generated from l-LOX/MOG in situ can result in decarboxylation of the imino acid, yielding an amide product, and extra H2O2 resulted in decarboxylation only of keto acids. Molecular dynamics simulations and detection of charge transfer species suggested that interactions between the substrate and its binding site on l-LOX/MOG are important for imino acid decarboxylation. Structural analysis indicated that the flavoenzyme oxidases catalyzing decarboxylation of an imino acid all share a common plug loop configuration that may facilitate this decarboxylation.
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Affiliation(s)
- Duangthip Trisrivirat
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand
| | - Daisuke Matsui
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Imizu, Japan.,Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Japan
| | - Yasuhisa Asano
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Imizu, Japan
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand .,School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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12
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Lin KH, Lyu SY, Yeh HW, Li YS, Hsu NS, Huang CM, Wang YL, Shih HW, Wang ZC, Wu CJ, Li TL. Structural and chemical trapping of flavin-oxide intermediates reveals substrate-directed reaction multiplicity. Protein Sci 2020; 29:1655-1666. [PMID: 32362037 PMCID: PMC7314388 DOI: 10.1002/pro.3879] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/02/2020] [Accepted: 04/28/2020] [Indexed: 11/29/2022]
Abstract
Though reactive flavin‐N5/C4α‐oxide intermediates can be spectroscopically profiled for some flavin‐assisted enzymatic reactions, their exact chemical configurations are hardly visualized. Structural systems biology and stable isotopic labelling techniques were exploited to correct this stereotypical view. Three transition‐like complexes, the α‐ketoacid…N5‐FMNox complex (I), the FMNox‐N5‐aloxyl‐C′α−‐C4α+ zwitterion (II), and the FMN‐N5‐ethenol‐N5‐C4α‐epoxide (III), were determined from mandelate oxidase (Hmo) or its mutant Y128F (monooxygenase) crystals soaked with monofluoropyruvate (a product mimic), establishing that N5 of FMNox an alternative reaction center can polarize to an ylide‐like mesomer in the active site. In contrast, four distinct flavin‐C4α‐oxide adducts (IV–VII) from Y128F crystals soaked with selected substrates materialize C4α of FMN an intrinsic reaction center, witnessing oxidation, Baeyer–Villiger/peroxide‐assisted decarboxylation, and epoxidation reactions. In conjunction with stopped‐flow kinetics, the multifaceted flavin‐dependent reaction continuum is physically dissected at molecular level for the first time. PDB Code(s): 5ZZT, 6A24, 6A1W, 6A01, 6A1N, 6A1B, 6A0B, 6A36, 6A4H, 6A4G, 6A3D, and 7BSR
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Affiliation(s)
- Kuan-Hung Lin
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.,The Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Syue-Yi Lyu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Hsien-Wei Yeh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Yi-Shan Li
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Ning-Shian Hsu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chun-Man Huang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Yung-Lin Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Hao-Wei Shih
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Zhe-Chong Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chang-Jer Wu
- Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan
| | - Tsung-Lin Li
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.,Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan.,Biotechnology Center, National Chung Hsing University, Taichung City, Taiwan
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13
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Su D, Smitherman C, Gadda G. A Metastable Photoinduced Protein–Flavin Adduct in Choline Oxidase, an Enzyme Not Involved in Light-Dependent Processes. J Phys Chem B 2020; 124:3936-3943. [DOI: 10.1021/acs.jpcb.0c02633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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14
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Phonbuppha J, Tinikul R, Wongnate T, Intasian P, Hollmann F, Paul CE, Chaiyen P. A Minimized Chemoenzymatic Cascade for Bacterial Luciferase in Bioreporter Applications. Chembiochem 2020; 21:2073-2079. [PMID: 32187433 DOI: 10.1002/cbic.202000100] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Indexed: 12/17/2022]
Abstract
Bacterial luciferase (Lux) catalyzes a bioluminescence reaction by using long-chain aldehyde, reduced flavin and molecular oxygen as substrates. The reaction can be applied in reporter gene systems for biomolecular detection in both prokaryotic and eukaryotic organisms. Because reduced flavin is unstable under aerobic conditions, another enzyme, flavin reductase, is needed to supply reduced flavin to the Lux-catalyzed reaction. To create a minimized cascade for Lux that would have greater ease of use, a chemoenzymatic reaction with a biomimetic nicotinamide (BNAH) was used in place of the flavin reductase reaction in the Lux system. The results showed that the minimized cascade reaction can be applied to monitor bioluminescence of the Lux reporter in eukaryotic cells effectively, and that it can achieve higher efficiencies than the system with flavin reductase. This development is useful for future applications as high-throughput detection tools for drug screening applications.
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Affiliation(s)
- Jittima Phonbuppha
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Moo 1, Payupnai, Wangchan, Rayong, 21210, Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, 272 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Moo 1, Payupnai, Wangchan, Rayong, 21210, Thailand
| | - Pattarawan Intasian
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Moo 1, Payupnai, Wangchan, Rayong, 21210, Thailand
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft (The, Netherlands
| | - Caroline E Paul
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft (The, Netherlands
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Moo 1, Payupnai, Wangchan, Rayong, 21210, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, 272 Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand
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15
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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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16
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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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17
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18
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Fabara AN, Fraaije MW. An overview of microbial indigo-forming enzymes. Appl Microbiol Biotechnol 2019; 104:925-933. [PMID: 31834440 PMCID: PMC6962290 DOI: 10.1007/s00253-019-10292-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/23/2019] [Accepted: 11/28/2019] [Indexed: 11/03/2022]
Abstract
Indigo is one of the oldest textile dyes and was originally prepared from plant material. Nowadays, indigo is chemically synthesized at a large scale to satisfy the demand for dyeing jeans. The current indigo production processes are based on fossil feedstocks; therefore, it is highly attractive to develop a more sustainable and environmentally friendly biotechnological process for the production of this popular dye. In the past decades, a number of natural and engineered enzymes have been identified that can be used for the synthesis of indigo. This mini-review provides an overview of the various microbial enzymes which are able to produce indigo and discusses the advantages and disadvantages of each biocatalytic system.
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Affiliation(s)
- Andrea N Fabara
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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19
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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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20
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Catalytic mechanism for the conversion of salicylate into catechol by the flavin-dependent monooxygenase salicylate hydroxylase. Int J Biol Macromol 2019; 129:588-600. [DOI: 10.1016/j.ijbiomac.2019.01.135] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/24/2019] [Accepted: 01/24/2019] [Indexed: 11/17/2022]
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21
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Robinson RM, Klancher CA, Rodriguez PJ, Sobrado P. Flavin oxidation in flavin-dependent N-monooxygenases. Protein Sci 2018; 28:90-99. [PMID: 30098072 DOI: 10.1002/pro.3487] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/14/2018] [Accepted: 07/23/2018] [Indexed: 01/08/2023]
Abstract
Siderophore A (SidA) from Aspergillus fumigatus is a flavin-containing monooxygenase that hydroxylates ornithine (Orn) at the amino group of the side chain. Lysine (Lys) also binds to the active site of SidA; however, hydroxylation is not efficient and H2 O2 is the main product. The effect of pH on steady-state kinetic parameters was measured and the results were consistent with Orn binding with the side chain amino group in the neutral form. From the pH dependence on flavin oxidation in the absence of Orn, a pKa value >9 was determined and assigned to the FAD-N5 atom. In the presence of Orn, the pH dependence displayed a pKa value of 6.7 ±0.1 and of 7.70 ±0.10 in the presence of Lys. Q102 interacts with NADPH and, upon mutation to alanine, leads to destabilization of the C4a-hydroperoxyflavin (FADOOH ). Flavin oxidation with Q102A showed a pKa value of ~8.0. The data are consistent with the pKa of the FAD N5-atom being modulated to a value >9 in the absence of Orn, which aids in the stabilization of FADOOH . Changes in the FAD-N5 environment lead to a decrease in the pKa value, which facilitates elimination of H2 O2 or H2 O. These findings are supported by solvent kinetic isotope effect experiments, which show that proton transfer from the FAD N5-atom is rate limiting in the absence of a substrate, however, is significantly less rate limiting in the presence of Orn and or Lys.
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Affiliation(s)
- Reeder M Robinson
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24061
| | - Catherine A Klancher
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24061
| | - Pedro J Rodriguez
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24061
| | - Pablo Sobrado
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24061
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22
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Barbosa ACC, Neves RPP, Sousa SF, Ramos MJ, Fernandes PA. Mechanistic Studies of a Flavin Monooxygenase: Sulfur Oxidation of Dibenzothiophenes by DszC. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ana C. C. Barbosa
- UCIBIO,REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Rui P. P. Neves
- UCIBIO,REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Sérgio F. Sousa
- UCIBIO,REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Maria J. Ramos
- UCIBIO,REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Pedro A. Fernandes
- UCIBIO,REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
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23
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Heine T, van Berkel WJH, Gassner G, van Pée KH, Tischler D. Two-Component FAD-Dependent Monooxygenases: Current Knowledge and Biotechnological Opportunities. BIOLOGY 2018; 7:biology7030042. [PMID: 30072664 PMCID: PMC6165268 DOI: 10.3390/biology7030042] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/11/2022]
Abstract
Flavoprotein monooxygenases create valuable compounds that are of high interest for the chemical, pharmaceutical, and agrochemical industries, among others. Monooxygenases that use flavin as cofactor are either single- or two-component systems. Here we summarize the current knowledge about two-component flavin adenine dinucleotide (FAD)-dependent monooxygenases and describe their biotechnological relevance. Two-component FAD-dependent monooxygenases catalyze hydroxylation, epoxidation, and halogenation reactions and are physiologically involved in amino acid metabolism, mineralization of aromatic compounds, and biosynthesis of secondary metabolites. The monooxygenase component of these enzymes is strictly dependent on reduced FAD, which is supplied by the reductase component. More and more representatives of two-component FAD-dependent monooxygenases have been discovered and characterized in recent years, which has resulted in the identification of novel physiological roles, functional properties, and a variety of biocatalytic opportunities.
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Affiliation(s)
- Thomas Heine
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - George Gassner
- Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
| | - Karl-Heinz van Pée
- Allgemeine Biochemie, Technische Universität Dresden, 01062 Dresden, Germany.
| | - Dirk Tischler
- Institute of Biosciences, Environmental Microbiology, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
- Microbial Biotechnology, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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24
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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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25
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Su D, Yuan H, Gadda G. A Reversible, Charge-Induced Intramolecular C4a-S-Cysteinyl-Flavin in Choline Oxidase Variant S101C. Biochemistry 2017; 56:6677-6690. [DOI: 10.1021/acs.biochem.7b00958] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dan Su
- Department
of Chemistry, ‡Department of Biology, §Center for Diagnostics and Therapeutics, and ∥Center for Biotechnology
and Drug Design, Georgia State University, Atlanta, Georgia 30302, United States
| | - Hongling Yuan
- Department
of Chemistry, ‡Department of Biology, §Center for Diagnostics and Therapeutics, and ∥Center for Biotechnology
and Drug Design, Georgia State University, Atlanta, Georgia 30302, United States
| | - Giovanni Gadda
- Department
of Chemistry, ‡Department of Biology, §Center for Diagnostics and Therapeutics, and ∥Center for Biotechnology
and Drug Design, Georgia State University, Atlanta, Georgia 30302, United States
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26
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Inactivation mechanism of N61S mutant of human FMO3 towards trimethylamine. Sci Rep 2017; 7:14668. [PMID: 29116146 PMCID: PMC5676948 DOI: 10.1038/s41598-017-15224-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/23/2017] [Indexed: 12/18/2022] Open
Abstract
Human flavin-containing monooxygenase 3 (hFMO3) catalyses the oxygenation of a wide variety of compounds including drugs as well as dietary compounds. It is the major hepatic enzyme involved in the production of the N-oxide of trimethylamine (TMAO) and clinical studies have uncovered a striking correlation between plasma TMAO concentration and cardiovascular disease. Certain mutations within the hFMO3 gene cause defective trimethylamine (TMA) N-oxygenation leading to trimethylaminuria (TMAU) also known as fish-odour syndrome. In this paper, the inactivation mechanism of a TMAU-causing polymorphic variant, N61S, is investigated. Transient kinetic experiments show that this variant has a > 170-fold lower NADPH binding affinity than the wild type. Thermodynamic and spectroscopic experiments reveal that the poor NADP+ binding affinity accelerates the C4a-hydroperoxyFAD intermediate decay, responsible for an unfavourable oxygen transfer to the substrate. Steady-state kinetic experiments show significantly decreased N61S catalytic activity towards other substrates; methimazole, benzydamine and tamoxifen. The in vitro data are corroborated by in silico data where compared to the wild type enzyme, a hydrogen bond required for the stabilisation of the flavin intermediate is lacking. Taken together, the data presented reveal the molecular basis for the loss of function observed in N61S mutant.
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27
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Flavin-catalyzed redox tailoring reactions in natural product biosynthesis. Arch Biochem Biophys 2017; 632:20-27. [DOI: 10.1016/j.abb.2017.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 11/21/2022]
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28
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Hino T, Hamamoto H, Suzuki H, Yagi H, Ohshiro T, Nagano S. Crystal structures of TdsC, a dibenzothiophene monooxygenase from the thermophile Paenibacillus sp. A11-2, reveal potential for expanding its substrate selectivity. J Biol Chem 2017; 292:15804-15813. [PMID: 28768765 DOI: 10.1074/jbc.m117.788513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/23/2017] [Indexed: 11/06/2022] Open
Abstract
Sulfur compounds in fossil fuels are a major source of environmental pollution, and microbial desulfurization has emerged as a promising technology for removing sulfur under mild conditions. The enzyme TdsC from the thermophile Paenibacillus sp. A11-2 is a two-component flavin-dependent monooxygenase that catalyzes the oxygenation of dibenzothiophene (DBT) to its sulfoxide (DBTO) and sulfone (DBTO2) during microbial desulfurization. The crystal structures of the apo and flavin mononucleotide (FMN)-bound forms of DszC, an ortholog of TdsC, were previously determined, although the structure of the ternary substrate-FMN-enzyme complex remains unknown. Herein, we report the crystal structures of the DBT-FMN-TdsC and DBTO-FMN-TdsC complexes. These ternary structures revealed many hydrophobic and hydrogen-bonding interactions with the substrate, and the position of the substrate could reasonably explain the two-step oxygenation of DBT by TdsC. We also determined the crystal structure of the indole-bound enzyme because TdsC, but not DszC, can also oxidize indole, and we observed that indole binding did not induce global conformational changes in TdsC with or without bound FMN. We also found that the two loop regions close to the FMN-binding site are disordered in apo-TdsC and become structured upon FMN binding. Alanine substitutions of Tyr-93 and His-388, which are located close to the substrate and FMN bound to TdsC, significantly decreased benzothiophene oxygenation activity, suggesting their involvement in supplying protons to the active site. Interestingly, these substitutions increased DBT oxygenation activity by TdsC, indicating that expanding the substrate-binding site can increase the oxygenation activity of TdsC on larger sulfur-containing substrates, a property that should prove useful for future microbial desulfurization applications.
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Affiliation(s)
- Tomoya Hino
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Haruka Hamamoto
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Hirokazu Suzuki
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Hisashi Yagi
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Takashi Ohshiro
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
| | - Shingo Nagano
- From the Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan
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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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30
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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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31
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van Beek HL, Romero E, Fraaije MW. Engineering Cyclohexanone Monooxygenase for the Production of Methyl Propanoate. ACS Chem Biol 2017; 12:291-299. [PMID: 27935281 DOI: 10.1021/acschembio.6b00965] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A previous study showed that cyclohexanone monooxygenase from Acinetobacter calcoaceticus (AcCHMO) catalyzes the Baeyer-Villiger oxidation of 2-butanone, yielding ethyl acetate and methyl propanoate as products. Methyl propanoate is of industrial interest as a precursor of acrylic plastic. Here, various residues near the substrate and NADP+ binding sites in AcCHMO were subjected to saturation mutagenesis to enhance both the activity on 2-butanone and the regioselectivity toward methyl propanoate. The resulting libraries were screened using whole cell biotransformations, and headspace gas chromatography-mass spectrometry was used to identify improved AcCHMO variants. This revealed that the I491A AcCHMO mutant exhibits a significant improvement over the wild type enzyme in the desired regioselectivity using 2-butanone as a substrate (40% vs 26% methyl propanoate, respectively). Another interesting mutant is the T56S AcCHMO mutant, which exhibits a higher conversion yield (92%) and kcat (0.5 s-1) than wild type AcCHMO (52% and 0.3 s-1, respectively). Interestingly, the uncoupling rate for the T56S AcCHMO mutant is also significantly lower than that for the wild type enzyme. The T56S/I491A double mutant combined the beneficial effects of both mutations leading to higher conversion and improved regioselectivity. This study shows that even for a relatively small aliphatic substrate (2-butanone), catalytic efficiency and regioselectivity can be tuned by structure-inspired enzyme engineering.
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Affiliation(s)
- Hugo L. van Beek
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Elvira Romero
- 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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32
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Thotsaporn K, Tinikul R, Maenpuen S, Phonbuppha J, Watthaisong P, Chenprakhon P, Chaiyen P. Enzymes in the p-hydroxyphenylacetate degradation pathway of Acinetobacter baumannii. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2016.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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33
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Gonzalez-Osorio L, Luong K, Jirde S, Palfey BA, Vey JL. Initial investigations of C4a-(hydro)peroxyflavin intermediate formation by dibenzothiophene monooxygenase. Biochem Biophys Res Commun 2016; 481:189-194. [PMID: 27815073 DOI: 10.1016/j.bbrc.2016.10.145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/29/2016] [Indexed: 11/17/2022]
Abstract
Dibenzothiophene monooxygenase is the initiating enzyme in the Rhodococcus 4S biodesulfurization pathway. A member of the Class D flavin monooxygenases, it uses FMN to activate molecular oxygen for oxygenation of the substrate, dibenzothiophene. Here, we have used stopped-flow spectrophotometry to show that DszC forms a peroxyflavin intermediate in the absence of substrate. Mutagenesis of Ser163 and His391 to Ala appears to decrease the binding affinity for reduced FMN and eliminates the enzyme's ability to stabilize the peroxyflavin intermediate.
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Affiliation(s)
- Liliana Gonzalez-Osorio
- Department of Chemistry and Biochemistry, California State University, Northridge, Northridge, CA 91330-8262, United States
| | - Kelvin Luong
- Department of Chemistry and Biochemistry, California State University, Northridge, Northridge, CA 91330-8262, United States
| | - Samatar Jirde
- Department of Chemistry and Biochemistry, California State University, Northridge, Northridge, CA 91330-8262, United States
| | - Bruce A Palfey
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Jessica L Vey
- Department of Chemistry and Biochemistry, California State University, Northridge, Northridge, CA 91330-8262, United States.
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Dhammaraj T, Pinthong C, Visitsatthawong S, Tongsook C, Surawatanawong P, Chaiyen P. A Single-Site Mutation at Ser146 Expands the Reactivity of the Oxygenase Component of p-Hydroxyphenylacetate 3-Hydroxylase. ACS Chem Biol 2016; 11:2889-2896. [PMID: 27541707 DOI: 10.1021/acschembio.6b00402] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxygenase component (C2) of p-hydroxyphenylacetate (4-HPA) 3-hydroxylase (HPAH) from Acinetobacter baumannii catalyzes the hydroxylation of various phenolic acids. In this report, we found that substitution of a residue close to the phenolic group binding site to yield the S146A variant resulted in an enzyme that is more effective than the wild-type in catalyzing the hydroxylation of 4-aminophenylacetate (4-APA). Product yields for both wild-type and S146A enzymes are better at lower pH values. Multiple turnover reactions of the wild-type and S146A enzymes indicate that both enzymes first hydroxylate 3-APA to give 3-hydroxy-4-aminophenylacetate (3-OH-4-APA), which is further hydroxylated to give 3,5-dihydroxy-4-aminophenylacetate, similar to the reaction of C2 with 4-HPA. Stopped-flow experiments showed that 4-APA can only bind to the wild-type enzyme at pH 6.0 and not at pH 9.0, while it can bind to S146A under both pH conditions. Rapid-quench flow results indicate that the wild-type enzyme has low reactivity toward 4-APA hydroxylation, with a hydroxylation rate constant (kOH) for 4-APA of 0.028 s-1 compared to 17 s-1 for 4-HPA, the native substrate. In contrast, for S146A, the hydroxylation rate constants for both substrates are very similar (2.6 s-1 for 4-HPA versus 2.5 s-1 for 4-APA). These data indicate that Ser146 is a key catalytic residue involved in optimizing C2 reactivity toward a phenolic compound. Removing this hydroxyl group expands C2 activity toward a non-natural aniline substrate. This understanding should be helpful for future rational engineering of other two-component flavin-dependent monooxygenases that have this conserved Ser residue.
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Affiliation(s)
- Taweesak Dhammaraj
- Department
of Biochemistry and Center for Excellence in Protein and Enzyme Technology,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Chatchadaporn Pinthong
- Department
of Biochemistry and Center for Excellence in Protein and Enzyme Technology,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
- Institute
for Innovative Learning, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Surawit Visitsatthawong
- Department
of Chemistry and Center of Excellence for Innovation in Chemistry,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Chanakan Tongsook
- Department
of Biochemistry and Center for Excellence in Protein and Enzyme Technology,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Panida Surawatanawong
- Department
of Chemistry and Center of Excellence for Innovation in Chemistry,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Pimchai Chaiyen
- Department
of Biochemistry and Center for Excellence in Protein and Enzyme Technology,
Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
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35
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Flavin-Dependent Redox Transfers by the Two-Component Diketocamphane Monooxygenases of Camphor-Grown Pseudomonas putida NCIMB 10007. Microorganisms 2016; 4:microorganisms4040038. [PMID: 27754389 PMCID: PMC5192521 DOI: 10.3390/microorganisms4040038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 11/23/2022] Open
Abstract
The progressive titres of key monooxygenases and their requisite native donors of reducing power were used to assess the relative contribution of various camphor plasmid (CAM plasmid)- and chromosome-coded activities to biodegradation of (rac)-camphor at successive stages throughout growth of Pseudomonas putida NCIMB 10007 on the bicylic monoterpenoid. A number of different flavin reductases (FRs) have the potential to supply reduced flavin mononucleotide to both 2,5- and 3,6-diketocamphane monooxygenase, the key isoenzymic two-component monooxygenases that delineate respectively the (+)- and (−)-camphor branches of the convergent degradation pathway. Two different constitutive chromosome-coded ferric reductases able to act as FRs can serve such as role throughout all stages of camphor-dependent growth, whereas Fred, a chromosome-coded inducible FR can only play a potentially significant role in the relatively late stages. Putidaredoxin reductase, an inducible CAM plasmid-coded flavoprotein that serves an established role as a redox intermediate for plasmid-coded cytochrome P450 monooxygenase also has the potential to serve as an important FR for both diketocamphane monooxygenases (DKCMOs) throughout most stages of camphor-dependent growth.
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36
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Sartor L, Ibarra C, Al-Mestarihi A, Bachmann BO, Vey JL. Structure of DnmZ, a nitrososynthase in the Streptomyces peucetius anthracycline biosynthetic pathway. Acta Crystallogr F Struct Biol Commun 2015; 71:1205-14. [PMID: 26457508 PMCID: PMC4601581 DOI: 10.1107/s2053230x15014272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/28/2015] [Indexed: 11/10/2022] Open
Abstract
The anthracyclines are a class of highly effective natural product chemotherapeutics and are used to treat a range of cancers, including leukemia. The toxicity of the anthracyclines has stimulated efforts to further diversify the scaffold of the natural product, which has led to renewed interest in the biosynthetic pathway responsible for the formation and modification of this family of molecules. DnmZ is an N-hydroxylating flavin monooxygenase (a nitrososynthase) that catalyzes the oxidation of the exocyclic amine of the sugar nucleotide dTDP-L-epi-vancosamine to its nitroso form. Its specific role in the anthracycline biosynthetic pathway involves the synthesis of the seven-carbon acetal moiety attached to C4 of L-daunosamine observed in the anthracycline baumycin. Here, X-ray crystallography was used to elucidate the three-dimensional structure of DnmZ. Two crystal structures of DnmZ were yielded: that of the enzyme alone, solved to 3.00 Å resolution, and that of the enzyme in complex with thymidine diphosphate, the nucleotide carrier portion of the substrate, solved to 2.74 Å resolution. These models add insights into the structural features involved in substrate specificity and conformational changes involved in thymidine diphosphate binding by the nitrososynthases.
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Affiliation(s)
- Lauren Sartor
- Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330, USA
| | - Charmaine Ibarra
- Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330, USA
| | - Ahmad Al-Mestarihi
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Brian O. Bachmann
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica L. Vey
- Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA 91330, USA
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37
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Visitsatthawong S, Chenprakhon P, Chaiyen P, Surawatanawong P. Mechanism of Oxygen Activation in a Flavin-Dependent Monooxygenase: A Nearly Barrierless Formation of C4a-Hydroperoxyflavin via Proton-Coupled Electron Transfer. J Am Chem Soc 2015; 137:9363-74. [DOI: 10.1021/jacs.5b04328] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Surawit Visitsatthawong
- Department
of Chemistry and Center of Excellence for Innovation in
Chemistry, Faculty of Science, †Institute for Innovative Learning, and ∥Department of
Biochemistry and Center of Excellence in Protein Structure and Function,
Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Pirom Chenprakhon
- Department
of Chemistry and Center of Excellence for Innovation in
Chemistry, Faculty of Science, †Institute for Innovative Learning, and ∥Department of
Biochemistry and Center of Excellence in Protein Structure and Function,
Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Pimchai Chaiyen
- Department
of Chemistry and Center of Excellence for Innovation in
Chemistry, Faculty of Science, †Institute for Innovative Learning, and ∥Department of
Biochemistry and Center of Excellence in Protein Structure and Function,
Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Panida Surawatanawong
- Department
of Chemistry and Center of Excellence for Innovation in
Chemistry, Faculty of Science, †Institute for Innovative Learning, and ∥Department of
Biochemistry and Center of Excellence in Protein Structure and Function,
Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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38
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Dhammaraj T, Phintha A, Pinthong C, Medhanavyn D, Tinikul R, Chenprakhon P, Sucharitakul J, Vardhanabhuti N, Jiarpinitnun C, Chaiyen P. p-Hydroxyphenylacetate 3-Hydroxylase as a Biocatalyst for the Synthesis of Trihydroxyphenolic Acids. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00439] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Taweesak Dhammaraj
- Department of Biochemistry and Center of
Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Aisaraphon Phintha
- Department of Biochemistry and Center of
Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Chatchadaporn Pinthong
- Department of Biochemistry and Center of
Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Dheeradhach Medhanavyn
- Department of Biochemistry and Center of
Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
| | - Ruchanok Tinikul
- Mahidol University, Nakhonsawan Campus, Nakhonsawan 60130, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Jeerus Sucharitakul
- Department
of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant
Road, Patumwan, Bangkok 10300, Thailand
| | - Nontima Vardhanabhuti
- Department of Pharmacy,
Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10300, Thailand
| | - Chutima Jiarpinitnun
- Department of Chemistry
and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Pimchai Chaiyen
- Department of Biochemistry and Center of
Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
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39
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Maenpuen S, Watthaisong P, Supon P, Sucharitakul J, Parsonage D, Karplus PA, Claiborne A, Chaiyen P. Kinetic mechanism of L-α-glycerophosphate oxidase from Mycoplasma pneumoniae. FEBS J 2015; 282:3043-59. [PMID: 25712468 DOI: 10.1111/febs.13247] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/17/2015] [Accepted: 02/20/2015] [Indexed: 12/16/2022]
Abstract
L-α-glycerophosphate oxidase is an FAD-dependent enzyme that catalyzes the oxidation of L-α-glycerophosphate (Glp) by molecular oxygen to generate dihydroxyacetone phosphate (DHAP) and hydrogen peroxide (H2O2). The catalytic properties of recombinant His6-GlpO from Mycoplasma pneumoniae (His6-MpGlpO) were investigated through transient and steady-state kinetics and ligand binding studies. The results indicate that the reaction mechanism of His6-MpGlpO follows a ping-pong model. Double-mixing mode stopped-flow experiments show that, after flavin-mediated substrate oxidation, DHAP leaves rapidly prior to the oxygen reaction. The values determined for the individual rate constants and kcat (4.2 s(-1) at 4 °C), in addition to the finding that H2 O2 binds to the oxidized enzyme, suggest that H2O2 release is the rate-limiting step for the overall reaction. The results indicate that His6 -MpGlpO contains mixed populations of fast- and slow-reacting species. It is predominantly the fast-reacting species that participates in turnover. In contrast to other GlpO enzymes previously described, His6-MpGlpO is able to catalyze the reverse reaction of reduced enzyme and DHAP. This result may be explained by the standard reduction potential value of His6-MpGlpO (-167 ± 1 mV), which is lower than those of GlpO from other species. We found that D,L-glyceraldehyde 3-phosphate (GAP) may be used as a substrate in the His6-MpGlpO reaction, although it exhibited an approximately 100-fold lower kcat value in comparison with the reaction of Glp. These results also imply involvement of GlpO in glycolysis, as well as in lipid and glycerol metabolism. The kinetic models and distinctive properties of His6-MpGlpO reported here should be useful for future drug development against Mycoplasma pneumoniae infection.
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Affiliation(s)
- Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Pratchaya Watthaisong
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Pacharee Supon
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Patumwan, Bangkok, Thailand
| | - Derek Parsonage
- Department of Biochemistry and Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - P Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Al Claiborne
- Department of Biochemistry and Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Pimchai Chaiyen
- Department of Biochemistry and Center of Excellence in Protein Structure & Function, Faculty of Science, Mahidol University, Bangkok, Thailand
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40
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Zafred D, Steiner B, Teufelberger AR, Hromic A, Karplus PA, Schofield CJ, Wallner S, Macheroux P. Rationally engineered flavin-dependent oxidase reveals steric control of dioxygen reduction. FEBS J 2015; 282:3060-74. [PMID: 25619330 DOI: 10.1111/febs.13212] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 01/12/2023]
Abstract
UNLABELLED The ability of flavoenzymes to reduce dioxygen varies greatly, and is controlled by the protein environment, which may cause either a rapid reaction (oxidases) or a sluggish reaction (dehydrogenases). Previously, a 'gatekeeper' amino acid residue was identified that controls the reactivity to dioxygen in proteins from the vanillyl alcohol oxidase superfamily of flavoenzymes. We have identified an alternative gatekeeper residue that similarly controls dioxygen reactivity in the grass pollen allergen Phl p 4, a member of this superfamily that has glucose dehydrogenase activity and the highest redox potential measured in a flavoenzyme. A substitution at the alternative gatekeeper site (I153V) transformed the enzyme into an efficient oxidase by increasing dioxygen reactivity by a factor of 60,000. An inverse exchange (V169I) in the structurally related berberine bridge enzyme (BBE) decreased its dioxygen reactivity by a factor of 500. Structural and biochemical characterization of these and additional variants showed that our model enzymes possess a cavity that binds an anion and resembles the 'oxyanion hole' in the proximity of the flavin ring. We showed also that steric control of access to this site is the most important parameter affecting dioxygen reactivity in BBE-like enzymes. Analysis of flavin-dependent oxidases from other superfamilies revealed similar structural features, suggesting that dioxygen reactivity may be governed by a common mechanistic principle. DATABASE Structural data are available in PDB database under the accession numbers 4PVE, 4PVH, 4PVJ, 4PVK, 4PWB, 4PWC and 4PZF.
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Affiliation(s)
- Domen Zafred
- Institute of Biochemistry, Graz University of Technology, Austria.,Institute of Molecular Biosciences, University of Graz, Austria
| | - Barbara Steiner
- Institute of Biochemistry, Graz University of Technology, Austria
| | | | - Altijana Hromic
- Institute of Molecular Biosciences, University of Graz, Austria
| | - P Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | | | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Austria
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41
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Sucharitakul J, Tinikul R, Chaiyen P. Mechanisms of reduced flavin transfer in the two-component flavin-dependent monooxygenases. Arch Biochem Biophys 2014; 555-556:33-46. [DOI: 10.1016/j.abb.2014.05.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/10/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
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42
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Chenprakhon P, Trisrivirat D, Thotsaporn K, Sucharitakul J, Chaiyen P. Control of C4a-Hydroperoxyflavin Protonation in the Oxygenase Component of p-Hydroxyphenylacetate-3-hydroxylase. Biochemistry 2014; 53:4084-6. [DOI: 10.1021/bi500480n] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
| | | | - Kittisak Thotsaporn
- Department
of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant, Patumwan, Bangkok 10300, Thailand
| | - Jeerus Sucharitakul
- Department
of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant, Patumwan, Bangkok 10300, Thailand
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43
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Frederick RE, Ojha S, Lamb A, Dubois JL. How pH modulates the reactivity and selectivity of a siderophore-associated flavin monooxygenase. Biochemistry 2014; 53:2007-16. [PMID: 24490904 PMCID: PMC3985866 DOI: 10.1021/bi401256b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Flavin-containing
monooxygenases (FMOs) catalyze the oxygenation
of diverse organic molecules using O2, NADPH, and the flavin
adenine dinucleotide (FAD) cofactor. The fungal FMO SidA initiates
peptidic siderophore biosynthesis via the highly selective hydroxylation
of l-ornithine, while the related amino acid l-lysine
is a potent effector of reaction uncoupling to generate H2O2. We hypothesized that protonation states could critically
influence both substrate-selective hydroxylation and H2O2 release, and therefore undertook a study of SidA’s
pH-dependent reaction kinetics. Consistent with other FMOs that stabilize
a C4a-OO(H) intermediate, SidA’s reductive half reaction is
pH independent. The rate constant for the formation of the reactive
C4a-OO(H) intermediate from reduced SidA and O2 is likewise
independent of pH. However, the rate constants for C4a-OO(H) reactions,
either to eliminate H2O2 or to hydroxylate l-Orn, were strongly pH-dependent and influenced by the nature
of the bound amino acid. Solvent kinetic isotope effects of 6.6 ±
0.3 and 1.9 ± 0.2 were measured for the C4a-OOH/H2O2 conversion in the presence and absence of l-Lys, respectively. A model is proposed in which l-Lys accelerates
H2O2 release via an acid–base mechanism
and where side-chain position determines whether H2O2 or the hydroxylation product is observed.
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Affiliation(s)
- Rosanne E Frederick
- Department of Chemistry and Biochemistry, University of Notre Dame , Notre Dame, Indiana 46556, United States
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44
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Wongnate T, Surawatanawong P, Visitsatthawong S, Sucharitakul J, Scrutton NS, Chaiyen P. Proton-Coupled Electron Transfer and Adduct Configuration Are Important for C4a-Hydroperoxyflavin Formation and Stabilization in a Flavoenzyme. J Am Chem Soc 2013; 136:241-53. [DOI: 10.1021/ja4088055] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Thanyaporn Wongnate
- Department
of Biochemistry and Center of Excellence in Protein Structure and
Function, Faculty of Science, Mahidol University, Bangkok, 10400 Thailand
| | - Panida Surawatanawong
- Department
of Chemistry and Center of Excellence for Innovation in Chemistry, Mahidol University, Bangkok 10400 Thailand
| | - Surawit Visitsatthawong
- Department
of Chemistry and Center of Excellence for Innovation in Chemistry, Mahidol University, Bangkok 10400 Thailand
| | - Jeerus Sucharitakul
- Department
of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant
Road, Patumwan, Bangkok, 10300 Thailand
| | - Nigel S. Scrutton
- Manchester
Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, Manchester M1 7DN United Kingdom
| | - Pimchai Chaiyen
- Department
of Biochemistry and Center of Excellence in Protein Structure and
Function, Faculty of Science, Mahidol University, Bangkok, 10400 Thailand
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45
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Huijbers MME, Montersino S, Westphal AH, Tischler D, van Berkel WJH. Flavin dependent monooxygenases. Arch Biochem Biophys 2013; 544:2-17. [PMID: 24361254 DOI: 10.1016/j.abb.2013.12.005] [Citation(s) in RCA: 359] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 11/29/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of chemo-, regio- and enantioselective oxygenation reactions. As such, they are involved in key biological processes ranging from catabolism, detoxification and biosynthesis, to light emission and axon guidance. Based on fold and function, flavin-dependent monooxygenases can be distributed into eight groups. Groups A and B comprise enzymes that rely on NAD(P)H as external electron donor. Groups C-F are two-protein systems, composed of a monooxygenase and a flavin reductase. Groups G and H comprise internal monooxygenases that reduce the flavin cofactor through substrate oxidation. Recently, many new flavin-dependent monooxygenases have been discovered. In addition to posing basic enzymological questions, these proteins attract attention of pharmaceutical and fine-chemical industries, given their importance as regio- and enantioselective biocatalysts. In this review we present an update of the classification of flavin-dependent monooxygenases and summarize the latest advances in our understanding of their catalytic and structural properties.
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Affiliation(s)
- Mieke M E Huijbers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Stefania Montersino
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Dirk Tischler
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands; Interdisciplinary Ecological Center, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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46
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Robinson R, Badieyan S, Sobrado P. C4a-hydroperoxyflavin formation in N-hydroxylating flavin monooxygenases is mediated by the 2'-OH of the nicotinamide ribose of NADP⁺. Biochemistry 2013; 52:9089-91. [PMID: 24321106 DOI: 10.1021/bi4014903] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Flavin-dependent monooxygenases must stabilize a C4a-hydroperoxyflavin intermediate to hydroxylate their respective substrates. Formation and decay of the C4a-hydroperoxyflavin were monitored under rapid reaction kinetic conditions in SidA, an N-hydroxylating monooxygenase involved in siderophore biosynthesis. Solvent kinetic isotope effect studies of flavin oxidation indicate that both hydrogen peroxide elimination and water elimination occur via abstraction of hydrogen from the N5 of the flavin. Kinetic isotope effect and density functional theory results are consistent with the transfer of a proton from the 2'-OH of the nicotinamide ribose of nicotinamide adenine dinucleotide phosphate (NADP⁺) to the C4a-peroxyflavin to form the C4a-hydroperoxyflavin. This represents a novel role for NADP⁺ in the reaction of flavin-dependent enzymes.
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Affiliation(s)
- Reeder Robinson
- Department of Biochemistry and ‡Virginia Tech Center for Drug Discovery, Virginia Tech , Blacksburg, Virginia 24061, United States
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47
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Teufel R, Miyanaga A, Michaudel Q, Stull F, Louie G, Noel JP, Baran PS, Palfey B, Moore BS. Flavin-mediated dual oxidation controls an enzymatic Favorskii-type rearrangement. Nature 2013; 503:552-556. [PMID: 24162851 PMCID: PMC3844076 DOI: 10.1038/nature12643] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 09/09/2013] [Indexed: 12/25/2022]
Abstract
Flavoproteins catalyze a diversity of fundamental redox reactions and are one of the most studied enzyme families1,2. As monooxygenases, they are universally thought to control oxygenation by means of a peroxyflavin species that transfers a single atom of molecular oxygen to an organic substrate1,3,4. Here we report that the bacterial flavoenzyme EncM5,6 catalyzes the peroxyflavin-independent oxygenation-dehydrogenation dual oxidation of a highly reactive poly(β-carbonyl). The crystal structure of EncM with bound substrate mimics coupled with isotope labeling studies reveal previously unknown flavin redox biochemistry. We show that EncM maintains an unanticipated stable flavin oxygenating species, proposed to be a flavin-N5-oxide, to promote substrate oxidation and trigger a rare Favorskii-type rearrangement that is central to the biosynthesis of the antibiotic enterocin. This work provides new insight into the fine-tuning of the flavin cofactor in offsetting the innate reactivity of a polyketide substrate to direct its efficient electrocyclization.
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Affiliation(s)
- Robin Teufel
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Akimasa Miyanaga
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Quentin Michaudel
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Frederick Stull
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Gordon Louie
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, Jack H. Skirball Center for Chemical Biology and Proteomics, La Jolla, California 92037, USA
| | - Joseph P Noel
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, Jack H. Skirball Center for Chemical Biology and Proteomics, La Jolla, California 92037, USA
| | - Phil S Baran
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Bruce Palfey
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, USA.,Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bradley S Moore
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, USA
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48
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Tischler D, Schlömann M, van Berkel WJH, Gassner GT. FAD C(4a)-hydroxide stabilized in a naturally fused styrene monooxygenase. FEBS Lett 2013; 587:3848-52. [PMID: 24157359 DOI: 10.1016/j.febslet.2013.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/08/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
Abstract
StyA2B represents a new class of styrene monooxygenases that integrates flavin-reductase and styrene-epoxidase activities into a single polypeptide. This naturally-occurring fusion protein offers new avenues for studying and engineering biotechnologically relevant enantioselective biochemical epoxidation reactions. Stopped-flow kinetic studies of StyA2B reported here identify reaction intermediates similar to those reported for the separate reductase and epoxidase components of related two-component systems. Our studies identify substrate epoxidation and elimination of water from the FAD C(4a)-hydroxide as rate-limiting steps in the styrene epoxidation reaction. Efforts directed at accelerating these reaction steps are expected to greatly increase catalytic efficiency and the value of StyA2B as biocatalyst.
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Affiliation(s)
- Dirk Tischler
- Interdisciplinary Ecological Center, TU Bergakadmie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany; Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands; Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, United States.
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49
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Sucharitakul J, Tongsook C, Pakotiprapha D, van Berkel WJH, Chaiyen P. The reaction kinetics of 3-hydroxybenzoate 6-hydroxylase from Rhodococcus jostii RHA1 provide an understanding of the para-hydroxylation enzyme catalytic cycle. J Biol Chem 2013; 288:35210-21. [PMID: 24129570 DOI: 10.1074/jbc.m113.515205] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
3-Hydroxybenzoate 6-hydroxylase (3HB6H) from Rhodococcus jostii RHA1 is an NADH-specific flavoprotein monooxygenase that catalyzes the para-hydroxylation of 3-hydroxybenzoate (3HB) to form 2,5-dihydroxybenzoate (2,5-DHB). Based on results from stopped-flow spectrophotometry, the reduced enzyme-3HB complex reacts with oxygen to form a C4a-peroxy flavin with a rate constant of 1.13 ± 0.01 × 10(6) m(-1) s(-1) (pH 8.0, 4 °C). This intermediate is subsequently protonated to form a C4a-hydroperoxyflavin with a rate constant of 96 ± 3 s(-1). This step shows a solvent kinetic isotope effect of 1.7. Based on rapid-quench measurements, the hydroxylation occurs with a rate constant of 36 ± 2 s(-1). 3HB6H does not exhibit substrate inhibition on the flavin oxidation step, a common characteristic found in most ortho-hydroxylation enzymes. The apparent kcat at saturating concentrations of 3HB, NADH, and oxygen is 6.49 ± 0.02 s(-1). Pre-steady state and steady-state kinetic data were used to construct the catalytic cycle of the reaction. The data indicate that the steps of product release (11.7 s(-1)) and hydroxylation (36 ± 2 s(-1)) partially control the overall turnover.
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Affiliation(s)
- Jeerus Sucharitakul
- From the Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri Dunant Road, Patumwan, Bangkok 10330, Thailand
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50
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Tinikul R, Pitsawong W, Sucharitakul J, Nijvipakul S, Ballou DP, Chaiyen P. The transfer of reduced flavin mononucleotide from LuxG oxidoreductase to luciferase occurs via free diffusion. Biochemistry 2013; 52:6834-43. [PMID: 24004065 DOI: 10.1021/bi4006545] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacterial luciferase (LuxAB) is a two-component flavin mononucleotide (FMN)-dependent monooxygenase that catalyzes the oxidation of reduced FMN (FMNH(-)) and a long-chain aliphatic aldehyde by molecular oxygen to generate oxidized FMN, the corresponding aliphatic carboxylic acid, and concomitant emission of light. The LuxAB reaction requires a flavin reductase to generate FMNH(-) to serve as a luciferin in its reaction. However, FMNH(-) is unstable and can react with oxygen to generate H2O2, so that it is important to transfer it efficiently to LuxAB. Recently, LuxG has been identified as a NADH:FMN oxidoreductase that supplies FMNH(-) to luciferase in vivo. In this report, the mode of transfer of FMNH(-) between LuxG from Photobacterium leiognathi TH1 and LuxABs from both P. leiognathi TH1 and Vibrio campbellii (PlLuxAB and VcLuxAB, respectively) was investigated using single-mixing and double-mixing stopped-flow spectrophotometry. The oxygenase component of p-hydroxyphenylacetate hydroxylase (C2) from Acinetobacter baumannii, which has no structural similarity to LuxAB, was used to measure the kinetics of release of FMNH(-) from LuxG. With all FMNH(-) acceptors used (C2, PlLuxAB, and VcLuxAB), the kinetics of FMN reduction on LuxG were the same, showing that LuxG releases FMNH(-) with a rate constant of 4.5-6 s(-1). Our data showed that the kinetics of binding of FMNH(-)to PlLuxAB and VcLuxAB and the subsequent reactions with oxygen were the same with either free FMNH(-) or FMNH(-) generated in situ by LuxG. These results strongly suggest that no complexes between LuxG and the various species are necessary to transfer FMNH(-) to the acceptors. The kinetics of the overall reactions and the individual rate constants correlate well with a free diffusion model for the transfer of FMNH(-) from LuxG to either LuxAB.
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Affiliation(s)
- Ruchanok Tinikul
- Mahidol University , Nakhonsawan Campus, Nakhonsawan 60130, Thailand
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