1
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Unusual reactivity of a flavin in a bifurcating electron-transferring flavoprotein leads to flavin modification and a charge-transfer complex. J Biol Chem 2022; 298:102606. [PMID: 36257407 PMCID: PMC9713284 DOI: 10.1016/j.jbc.2022.102606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/08/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
From the outset, canonical electron transferring flavoproteins (ETFs) earned a reputation for containing modified flavin. We now show that modification occurs in the recently recognized bifurcating (Bf) ETFs as well. In Bf ETFs, the 'electron transfer' (ET) flavin mediates single electron transfer via a stable anionic semiquinone state, akin to the FAD of canonical ETFs, whereas a second flavin mediates bifurcation (the Bf FAD). We demonstrate that the ET FAD undergoes transformation to two different modified flavins by a sequence of protein-catalyzed reactions that occurs specifically in the ET site, when the enzyme is maintained at pH 9 in an amine-based buffer. Our optical and mass spectrometric characterizations identify 8-formyl flavin early in the process and 8-amino flavins (8AFs) at later times. The latter have not previously been documented in an ETF to our knowledge. Mass spectrometry of flavin products formed in Tris or bis-tris-aminopropane solutions demonstrates that the source of the amine adduct is the buffer. Stepwise reduction of the 8AF demonstrates that it can explain a charge transfer band observed near 726 nm in Bf ETF, as a complex involving the hydroquinone state of the 8AF in the ET site with the oxidized state of unmodified flavin in the Bf site. This supports the possibility that Bf ETF can populate a conformation enabling direct electron transfer between its two flavins, as has been proposed for cofactors brought together in complexes between ETF and its partner proteins.
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2
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WANG M, ZHANG W, WANG N. Covalent flavoproteins: types, occurrence, biogenesis and catalytic mechanisms. Chin J Nat Med 2022; 20:749-760. [DOI: 10.1016/s1875-5364(22)60194-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Indexed: 11/03/2022]
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3
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Pereira MS, de Araújo SS, Nagem RAP, Richard JP, Brandão TAS. The role of remote flavin adenine dinucleotide pieces in the oxidative decarboxylation catalyzed by salicylate hydroxylase. Bioorg Chem 2022; 119:105561. [PMID: 34965488 PMCID: PMC8824312 DOI: 10.1016/j.bioorg.2021.105561] [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: 09/17/2021] [Revised: 11/19/2021] [Accepted: 12/11/2021] [Indexed: 02/03/2023]
Abstract
Salicylate hydroxylase (NahG) has a single redox site in which FAD is reduced by NADH, the O2 is activated by the reduced flavin, and salicylate undergoes an oxidative decarboxylation by a C(4a)-hydroperoxyflavin intermediate to give catechol. We report experimental results that show the contribution of individual pieces of the FAD cofactor to the observed enzymatic activity for turnover of the whole cofactor. A comparison of the kinetic parameters and products for the NahG-catalyzed reactions of FMN and riboflavin cofactor fragments reveal that the adenosine monophosphate (AMP) and ribitol phosphate pieces of FAD act to anchor the flavin to the enzyme and to direct the partitioning of the C(4a)-hydroperoxyflavin reaction intermediate towards hydroxylation of salicylate. The addition of AMP or ribitol phosphate pieces to solutions of the truncated flavins results in a partial restoration of the enzymatic activity lost upon truncation of FAD, and the pieces direct the reaction of the C(4a)-hydroperoxyflavin intermediate towards hydroxylation of salicylate.
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Affiliation(s)
- Mozart S. Pereira
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Simara S. de Araújo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Ronaldo A. P. Nagem
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - John P. Richard
- Department of Chemistry, University at Buffalo, SUNY, Buffalo, New York 14260-3000,CORRESPONDING AUTHOR: ;
| | - Tiago A. S. Brandão
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil.,CORRESPONDING AUTHOR: ;
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4
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Pan D, Gong X, Wang X, Li M. Role of Active Components of Medicinal Food in the Regulation of Angiogenesis. Front Pharmacol 2021; 11:594050. [PMID: 33716724 PMCID: PMC7944143 DOI: 10.3389/fphar.2020.594050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/10/2020] [Indexed: 11/16/2022] Open
Abstract
Angiogenesis refers to the formation of new blood vessels from the endothelial cells of existing arteries, veins, and capillaries. Angiogenesis is involved in a variety of physiological and pathological processes, such as the formation of malignant and development of atherosclerosis and other diseases. In recent years, many studies have shown that the active components of food have a certain regulatory effect on angiogenesis and negligible clinical limitations. With the increasing attention being paid to medicine and food homology, exploring the effect of active food components on angiogenesis is of great significance. In this review, we discuss the source, composition, pharmacological activity, and mechanism of action of certain active components of medicinal foods in detail. These could help prevent angiogenesis-related complications or provide a basis for healthier dietary habits. This review can provide a theoretical basis for the research and development of highly efficient anti-angiogenic drugs with low toxicity.
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Affiliation(s)
- Dezhi Pan
- Department of Pharmacy, Inner Mongolia Medical University, Hohhot, China
| | - Xue Gong
- Department of Pharmacy, Baotou Medical College, Baotou, China
| | - Xiaoqin Wang
- Department of Pharmacy, Inner Mongolia Medical University, Hohhot, China
| | - Minhui Li
- Department of Pharmacy, Inner Mongolia Medical University, Hohhot, China
- Department of Pharmacy, Baotou Medical College, Baotou, China
- Pharmaceutical Laboratory, Inner Mongolia Institute of Traditional Chinese Medicine, Hohhot, China
- Inner Mongolia Key Laboratory of Characteristic Geoherbs Resources Protection and Utilization, Baotou Medical College, Baotou, China
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5
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The roles of SDHAF2 and dicarboxylate in covalent flavinylation of SDHA, the human complex II flavoprotein. Proc Natl Acad Sci U S A 2020; 117:23548-23556. [PMID: 32887801 DOI: 10.1073/pnas.2007391117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial complex II, also known as succinate dehydrogenase (SDH), is an integral-membrane heterotetramer (SDHABCD) that links two essential energy-producing processes, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. A significant amount of information is available on the structure and function of mature complex II from a range of organisms. However, there is a gap in our understanding of how the enzyme assembles into a functional complex, and disease-associated complex II insufficiency may result from incorrect function of the mature enzyme or from assembly defects. Here, we investigate the assembly of human complex II by combining a biochemical reconstructionist approach with structural studies. We report an X-ray structure of human SDHA and its dedicated assembly factor SDHAF2. Importantly, we also identify a small molecule dicarboxylate that acts as an essential cofactor in this process and works in synergy with SDHAF2 to properly orient the flavin and capping domains of SDHA. This reorganizes the active site, which is located at the interface of these domains, and adjusts the pKa of SDHAR451 so that covalent attachment of the flavin adenine dinucleotide (FAD) cofactor is supported. We analyze the impact of disease-associated SDHA mutations on assembly and identify four distinct conformational forms of the complex II flavoprotein that we assign to roles in assembly and catalysis.
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6
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Abstract
This review presents a historical outline of the research on vanillyl alcohol oxidase (VAO) from Penicillium simplicissimum, one of the canonical members of the VAO/PCMH flavoprotein family. After describing its discovery and initial biochemical characterization, we discuss the physiological role, substrate scope, and catalytic mechanism of VAO, and review its three-dimensional structure and mechanism of covalent flavinylation. We also explain how protein engineering provided a deeper insight into the role of certain amino acid residues in determining the substrate specificity and enantioselectivity of the enzyme. Finally, we summarize recent computational studies about the migration of substrates and products through the enzyme's structure and the phylogenetic distribution of VAO and related enzymes.
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Affiliation(s)
- Tom A Ewing
- Wageningen Food & Biobased Research, Wageningen University & Research, Wageningen, The Netherlands
| | - Gudrun Gygli
- Institute for Biological Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Groningen, The Netherlands
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University & Research, Wageningen, The Netherlands.
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7
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Fujieda N. His-Cys and Trp-Cys cross-links generated by post-translational chemical modification. Biosci Biotechnol Biochem 2019; 84:445-454. [PMID: 31771431 DOI: 10.1080/09168451.2019.1696178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Galactose oxidase and amine oxidase contain a cofactor which is generated by post-translational chemical modification to the corresponding amino acid side chains near the copper active center. Such cofactors provide proteins unusual catalytic ability that canonical amino acids cannot exert as well as their structural stability, and thereby are called as protein-derived cofactors. These cofactors and modifications are mostly derived from aromatic amino acid residues, especially Tyr, Trp, and His. Current information about unusual cofactors derived from two of those, heteroaromatic residues (Trp and His) is summarized, especially chemical properties and maturation process of the cross-links between cysteine and heteroaromatic amino acids (His-Cys and Trp-Cys cross-links).Abbreviations: FMN: flavin mononucleotide; FAD: flavin adenine nucleotide; RNA: ribonucleic acid; PDC: protein-derived cofactor; GFP: green fluorescent protein; MIO: 3,5-dihydro-5-methylidene-4-imidazol-4-one; LTQ: lysyl tyrosylquinone; CTQ: cysteine tryptophylquinone; TTQ: tryptophan tryptophylquinone; E.coli: Escherichia coli; WT: wild type.
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Affiliation(s)
- Nobutaka Fujieda
- Department of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan
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8
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Moosavi B, Berry EA, Zhu XL, Yang WC, Yang GF. The assembly of succinate dehydrogenase: a key enzyme in bioenergetics. Cell Mol Life Sci 2019; 76:4023-4042. [PMID: 31236625 PMCID: PMC11105593 DOI: 10.1007/s00018-019-03200-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/30/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022]
Abstract
Succinate dehydrogenase (SDH) also known as complex II or succinate:quinone oxidoreductase is an enzyme involved in both oxidative phosphorylation and tricarboxylic acid cycle; the processes that generate energy. SDH is a multi-subunit enzyme which requires a series of proteins for its proper assembly at several steps. This enzyme has medical significance as there is a broad range of human diseases from cancers to neurodegeneration related to SDH malfunction. Some of these disorders have recently been linked to defective assembly factors, reinvigorating further research in this area. Apart from that this enzyme has agricultural importance as many fungicides have been/will be designed targeting specifically this enzyme in plant fungal pathogens. In addition, we speculate it might be possible to design novel fungicides specifically targeting fungal assembly factors. Considering the medical and agricultural implications of SDH, the aim of this review is an overview of the SDH assembly factors and critical analysis of controversial issues around them.
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Affiliation(s)
- Behrooz Moosavi
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Edward A Berry
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Xiao-Lei Zhu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Wen-Chao Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, People's Republic of China.
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9
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Sharma P, Maklashina E, Cecchini G, Iverson TM. Maturation of the respiratory complex II flavoprotein. Curr Opin Struct Biol 2019; 59:38-46. [PMID: 30851631 DOI: 10.1016/j.sbi.2019.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 12/13/2022]
Abstract
Respiratory complexes are complicated multi-subunit cofactor-containing machines that allow cells to harvest energy from the environment. Maturation of these complexes requires protein folding, cofactor insertion, and assembly of multiple subunits into a final, functional complex. Because the intermediate states in complex maturation are transitory, these processes are poorly understood. This review gives an overview of the process of maturation in respiratory complex II with a focus on recent structural studies on intermediates formed during covalent flavinylation of the catalytic subunit, SDHA. Covalent flavinylation has an evolutionary significance because variants of complex II enzymes with the covalent ligand removed by mutagenesis cannot oxidize succinate, but can still perform the reverse reaction and reduce fumarate. Since succinate oxidation is a key step of aerobic respiration, the covalent bond of complex II appears to be important for aerobic life.
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Affiliation(s)
- Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, United States.
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10
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Huijbers MME, Martínez-Júlvez M, Westphal AH, Delgado-Arciniega E, Medina M, van Berkel WJH. Proline dehydrogenase from Thermus thermophilus does not discriminate between FAD and FMN as cofactor. Sci Rep 2017; 7:43880. [PMID: 28256579 PMCID: PMC5335563 DOI: 10.1038/srep43880] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/30/2017] [Indexed: 12/19/2022] Open
Abstract
Flavoenzymes are versatile biocatalysts containing either FAD or FMN as cofactor. FAD often binds to a Rossmann fold, while FMN prefers a TIM-barrel or flavodoxin-like fold. Proline dehydrogenase is denoted as an exception: it possesses a TIM barrel-like fold while binding FAD. Using a riboflavin auxotrophic Escherichia coli strain and maltose-binding protein as solubility tag, we produced the apoprotein of Thermus thermophilus ProDH (MBP-TtProDH). Remarkably, reconstitution with FAD or FMN revealed that MBP-TtProDH has no preference for either of the two prosthetic groups. Kinetic parameters of both holo forms are similar, as are the dissociation constants for FAD and FMN release. Furthermore, we show that the holo form of MBP-TtProDH, as produced in E. coli TOP10 cells, contains about three times more FMN than FAD. In line with this flavin content, the crystal structure of TtProDH variant ΔABC, which lacks helices αA, αB and αC, shows no electron density for an AMP moiety of the cofactor. To the best of our knowledge, this is the first example of a flavoenzyme that does not discriminate between FAD and FMN as cofactor. Therefore, classification of TtProDH as an FAD-binding enzyme should be reconsidered.
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Affiliation(s)
- Mieke M. E. Huijbers
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Marta Martínez-Júlvez
- Department of Biochemistry and Molecular Cell Biology and Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Adrie H. Westphal
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Estela Delgado-Arciniega
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Milagros Medina
- Department of Biochemistry and Molecular Cell Biology and Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Willem J. H. van Berkel
- Laboratory of Biochemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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11
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Konjik V, Brünle S, Demmer U, Vanselow A, Sandhoff R, Ermler U, Mack M. Die Kristallstruktur von RosB: Einblicke in den Reaktionsmechanismus des ersten Mitglieds einer flavodoxinähnlichen Enzymfamilie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Valentino Konjik
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
| | - Steffen Brünle
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Ulrike Demmer
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Amanda Vanselow
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
| | - Roger Sandhoff
- Deutsches Krebsforschungszentrum (DKFZ); Im Neuenheimer Feld 280 69120 Heidelberg Deutschland
| | - Ulrich Ermler
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Matthias Mack
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
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12
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Konjik V, Brünle S, Demmer U, Vanselow A, Sandhoff R, Ermler U, Mack M. The Crystal Structure of RosB: Insights into the Reaction Mechanism of the First Member of a Family of Flavodoxin-like Enzymes. Angew Chem Int Ed Engl 2016; 56:1146-1151. [DOI: 10.1002/anie.201610292] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Valentino Konjik
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
| | - Steffen Brünle
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Ulrike Demmer
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Amanda Vanselow
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
| | - Roger Sandhoff
- German Cancer Research Center (DKFZ); Im Neuenheimer Feld 280 69120 Heidelberg Germany
| | - Ulrich Ermler
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Matthias Mack
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
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13
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Jhulki I, Chanani PK, Abdelwahed SH, Begley TP. A Remarkable Oxidative Cascade That Replaces the Riboflavin C8 Methyl with an Amino Group during Roseoflavin Biosynthesis. J Am Chem Soc 2016; 138:8324-7. [PMID: 27331868 PMCID: PMC5610575 DOI: 10.1021/jacs.6b02469] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Roseoflavin is a naturally occurring riboflavin analogue with antibiotic properties. It is biosynthesized from riboflavin in a reaction involving replacement of the C8 methyl with a dimethylamino group. Herein we report the identification of a flavin-dependent enzyme that converts flavin mononucleotide (FMN) and glutamate to 8-amino-FMN via the intermediacy of 8-formyl-FMN. A mechanistic proposal for this remarkable transformation is proposed.
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Affiliation(s)
- Isita Jhulki
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Prem K. Chanani
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Sameh H. Abdelwahed
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843, United States
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14
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Ewing TA, Gygli G, van Berkel WJH. A single loop is essential for the octamerization of vanillyl alcohol oxidase. FEBS J 2016; 283:2546-59. [PMID: 27214042 DOI: 10.1111/febs.13762] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 05/20/2016] [Indexed: 11/30/2022]
Abstract
UNLABELLED The VAO/PCMH family of flavoenzymes is a family of structurally related proteins that catalyse a wide range of oxidation reactions. It contains a subfamily of enzymes that catalyse the oxidation of para-substituted phenols using covalently bound FAD cofactors (the 4PO subfamily). This subfamily is composed of two oxidases, vanillyl alcohol oxidase (VAO) and eugenol oxidase (EUGO), and two flavocytochrome dehydrogenases, para-cresol methylhydroxylase (PCMH) and eugenol hydroxylase (EUGH). Although they catalyse similar reactions, these enzymes differ in terms of their electron acceptor preference and oligomerization state. For example, VAO forms homo-octamers that can be described as tetramers of stable dimers, whereas EUGO is exclusively dimeric in solution. A possible explanation for this difference is the presence of a loop at the dimer-dimer interface in VAO that is not present in EUGO. Here, the role played by this loop in determining the quaternary structure of these enzymes is investigated. A VAO variant where the loop was deleted, loopless VAO, exclusively formed dimers. However, introduction of the loop into EUGO was not sufficient to induce its octamerization. Neither variant displayed major changes in its catalytic properties as compared to the wild-type enzyme. Bioinformatic analysis revealed that the presence of the loop is conserved within putative fungal oxidases of the 4PO subgroup, but it is never found in putative bacterial oxidases or dehydrogenases. Our results shed light on the molecular mechanism of homo-oligomerization of VAO and the importance of oligomerization for its enzymatic function. ENZYMES p-cresol methylhydroxylase (4-methylphenol:acceptor oxidoreductase (methyl-hydroxylating), EC 1.17.99.1); vanillyl alcohol oxidase (vanillyl alcohol:oxygen oxidoreductase, EC 1.1.3.38).
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Affiliation(s)
- Tom A Ewing
- Laboratory of Biochemistry, Wageningen University, The Netherlands
| | - Gudrun Gygli
- Laboratory of Biochemistry, Wageningen University, The Netherlands
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15
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Cheng VWT, Piragasam RS, Rothery RA, Maklashina E, Cecchini G, Weiner JH. Redox state of flavin adenine dinucleotide drives substrate binding and product release in Escherichia coli succinate dehydrogenase. Biochemistry 2015; 54:1043-52. [PMID: 25569225 DOI: 10.1021/bi501350j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Complex II family of enzymes, comprising respiratory succinate dehydrogenases and fumarate reductases, catalyzes reversible interconversion of succinate and fumarate. In contrast to the covalent flavin adenine dinucleotide (FAD) cofactor assembled in these enzymes, soluble fumarate reductases (e.g., those from Shewanella frigidimarina) that assemble a noncovalent FAD cannot catalyze succinate oxidation but retain the ability to reduce fumarate. In this study, an SdhA-H45A variant that eliminates the site of the 8α-N3-histidyl covalent linkage between the protein and FAD was examined. Variants SdhA-R286A/K/Y and -H242A/Y that target residues thought to be important for substrate binding and catalysis were also studied. The variants SdhA-H45A and -R286A/K/Y resulted in the assembly of a noncovalent FAD cofactor, which led to a significant decrease (-87 mV or more) in its reduction potential. The variant enzymes were studied by electron paramagnetic resonance spectroscopy following stand-alone reduction and potentiometric titrations. The "free" and "occupied" states of the active site were linked to the reduced and oxidized states of FAD, respectively. Our data allow for a proposed model of succinate oxidation that is consistent with tunnel diode effects observed in the succinate dehydrogenase enzyme and a preference for fumarate reduction catalysis in fumarate reductase homologues that assemble a noncovalent FAD.
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Affiliation(s)
- Victor W T Cheng
- Department of Biochemistry, University of Alberta , Edmonton, Alberta T6G 2H7, Canada
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16
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Kopacz MM, Fraaije MW. Turning a monocovalent flavoprotein into a bicovalent flavoprotein by structure-inspired mutagenesis. Bioorg Med Chem 2014; 22:5621-7. [DOI: 10.1016/j.bmc.2014.05.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
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17
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Krondorfer I, Brugger D, Paukner R, Scheiblbrandner S, Pirker KF, Hofbauer S, Furtmüller PG, Obinger C, Haltrich D, Peterbauer CK. Agaricus meleagris pyranose dehydrogenase: influence of covalent FAD linkage on catalysis and stability. Arch Biochem Biophys 2014; 558:111-9. [PMID: 25043975 PMCID: PMC4148704 DOI: 10.1016/j.abb.2014.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 07/04/2014] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
Abstract
Pyranose dehydrogenase (PDH) is a monomeric flavoprotein belonging to the glucose-methanol-choline (GMC) family of oxidoreductases. It catalyzes the oxidation of free, non-phosphorylated sugars to the corresponding keto sugars. The enzyme harbors an FAD cofactor that is covalently attached to histidine 103 via an 8α-N(3) histidyl linkage. Our previous work showed that variant H103Y was still able to bind FAD (non-covalently) and perform catalysis but steady-state kinetic parameters for several substrates were negatively affected. In order to investigate the impact of the covalent FAD attachment in Agaricus meleagris PDH in more detail, pre-steady-state kinetics, reduction potential and stability of the variant H103Y in comparison to the wild-type enzyme were probed. Stopped-flow analysis revealed that the mutation slowed down the reductive half-reaction by around three orders of magnitude whereas the oxidative half-reaction was affected only to a minor degree. This was reflected by a decrease in the standard reduction potential of variant H103Y compared to the wild-type protein. The existence of an anionic semiquinone radical in the resting state of both the wild-type and variant H103Y was demonstrated using electron paramagnetic resonance (EPR) spectroscopy and suggested a higher mobility of the cofactor in the variant H103Y. Unfolding studies showed significant negative effects of the disruption of the covalent bond on thermal and conformational stability. The results are discussed with respect to the role of covalently bound FAD in catalysis and stability.
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Affiliation(s)
- Iris Krondorfer
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Dagmar Brugger
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Regina Paukner
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Stefan Scheiblbrandner
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Katharina F Pirker
- Department of Chemistry, Division of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Stefan Hofbauer
- Department of Chemistry, Division of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Paul G Furtmüller
- Department of Chemistry, Division of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Division of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Dietmar Haltrich
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria
| | - Clemens K Peterbauer
- Department of Food Science and Technology, Food Biotechnology Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria.
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18
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McNeil MB, Hampton HG, Hards KJ, Watson BNJ, Cook GM, Fineran PC. The succinate dehydrogenase assembly factor, SdhE, is required for the flavinylation and activation of fumarate reductase in bacteria. FEBS Lett 2013; 588:414-21. [PMID: 24374335 DOI: 10.1016/j.febslet.2013.12.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 12/04/2013] [Accepted: 12/08/2013] [Indexed: 12/29/2022]
Abstract
The activity of the respiratory enzyme fumarate reductase (FRD) is dependent on the covalent attachment of the redox cofactor flavin adenine dinucleotide (FAD). We demonstrate that the FAD assembly factor SdhE, which flavinylates and activates the respiratory enzyme succinate dehydrogenase (SDH), is also required for the complete activation and flavinylation of FRD. SdhE interacted with, and flavinylated, the flavoprotein subunit FrdA, whilst mutations in a conserved RGxxE motif impaired the complete flavinylation and activation of FRD. These results are of widespread relevance because SDH and FRD play an important role in cellular energetics and are required for virulence in many important bacterial pathogens.
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Affiliation(s)
- Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Hannah G Hampton
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Kiel J Hards
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Bridget N J Watson
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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19
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McNeil MB, Fineran PC. The conserved RGxxE motif of the bacterial FAD assembly factor SdhE is required for succinate dehydrogenase flavinylation and activity. Biochemistry 2013; 52:7628-40. [PMID: 24070374 DOI: 10.1021/bi401006a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Succinate dehydrogenase (SDH) is an important respiratory enzyme that plays a critical role in the generation of energy in the majority of eukaryotes, bacteria, and archaea. The activity of SDH is dependent on the covalent attachment of the redox cofactor FAD to the flavoprotein subunit SdhA. In the Gram-negative bacteria Escherichia coli and Serratia sp. ATCC 39006, the covalent attachment of FAD to SdhA is dependent on the FAD assembly factor SdhE (YgfY). Although mechanisms have been proposed, experimental evidence that elucidates the molecular details of SdhE-mediated flavinylation are scarce. In this study, truncation and alanine swap mutagenesis of SdhE identified a highly conserved RGxxE motif that was important for SdhE function. Interestingly, RGxxE site-directed variants were not impaired in terms of protein folding or interactions with SdhA. Purification and analysis of SdhA from different mutant backgrounds demonstrated that SdhE interacts with and flavinylates folded SdhA without a requirement for the assembly of the entire SDH complex. SdhA was also partially active in the absence of SdhE, suggesting that SdhA is able to attach FAD through an inefficient autocatalytic mechanism. The results presented are of widespread relevance because SdhE and SDH are required for bacterial pathogenesis and mutations in the eukaryotic homologues of SdhE and SDH are associated with cancer in humans.
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Affiliation(s)
- Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand
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20
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Hofzumahaus S, Schallmey A. Escherichia coli-based expression system for the heterologous expression and purification of the elicitin β-cinnamomin from Phytophthora cinnamomi. Protein Expr Purif 2013; 90:117-23. [PMID: 23747816 DOI: 10.1016/j.pep.2013.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/17/2013] [Accepted: 05/18/2013] [Indexed: 10/26/2022]
Abstract
Elicitins are sterol carrier proteins from the Oomycete genera Phytophthora and Phytium and elicit a hypersensitive response in many economically important plants, in some cases causing a systemic acquired resistance. Their recombinant expression in bacteria is complicated by the presence of three disulfide bonds in the elicitin structure. In consequence, elicitins have so far only been produced in soluble form by isolation from native Phytophthora or Phytium strains or by recombinant expression in the yeast Pichia pastoris. Here, for the first time, we report the soluble expression of the elicitin β-cinnamomin from Phytophthora cinnamomi in Escherichia coli by secretion of the protein into the periplasm. β-Cinnamomin yields have been significantly improved after careful selection of the optimum secretion signal sequence. In total, 17.6 mg β-cinnamomin per liter cell culture have been obtained in shake flasks with the secretion signal sequence of the maltose-binding protein MalE from E. coli. Furthermore, by making use of a C-terminal His-tag, β-cinnamomin purification has been significantly simplified with only one step of immobilized metal ion affinity chromatography yielding protein of high purity (>90%). The established protocol has further been successfully applied to the soluble expression of another elicitin.
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21
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Schallmey M, Floor RJ, Hauer B, Breuer M, Jekel PA, Wijma HJ, Dijkstra BW, Janssen DB. Biocatalytic and structural properties of a highly engineered halohydrin dehalogenase. Chembiochem 2013; 14:870-81. [PMID: 23585096 DOI: 10.1002/cbic.201300005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Indexed: 01/30/2023]
Abstract
Two highly engineered halohydrin dehalogenase variants were characterized in terms of their performance in dehalogenation and epoxide cyanolysis reactions. Both enzyme variants outperformed the wild-type enzyme in the cyanolysis of ethyl (S)-3,4-epoxybutyrate, a conversion yielding ethyl (R)-4-cyano-3-hydroxybutyrate, an important chiral building block for statin synthesis. One of the enzyme variants, HheC2360, displayed catalytic rates for this cyanolysis reaction enhanced up to tenfold. Furthermore, the enantioselectivity of this variant was the opposite of that of the wild-type enzyme, both for dehalogenation and for cyanolysis reactions. The 37-fold mutant HheC2360 showed an increase in thermal stability of 8 °C relative to the wild-type enzyme. Crystal structures of this enzyme were elucidated with chloride and ethyl (S)-3,4-epoxybutyrate or with ethyl (R)-4-cyano-3-hydroxybutyrate bound in the active site. The observed increase in temperature stability was explained in terms of a substantial increase in buried surface area relative to the wild-type HheC, together with enhanced interfacial interactions between the subunits that form the tetramer. The structures also revealed that the substrate binding pocket was modified both by substitutions and by backbone movements in loops surrounding the active site. The observed changes in the mutant structures are partly governed by coupled mutations, some of which are necessary to remove steric clashes or to allow backbone movements to occur. The importance of interactions between substitutions suggests that efficient directed evolution strategies should allow for compensating and synergistic mutations during library design.
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Affiliation(s)
- Marcus Schallmey
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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22
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Kim HJ, Winge DR. Emerging concepts in the flavinylation of succinate dehydrogenase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:627-36. [PMID: 23380393 DOI: 10.1016/j.bbabio.2013.01.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/28/2022]
Abstract
The Succinate Dehydrogenase (SDH) heterotetrameric complex catalyzes the oxidation of succinate to fumarate in the tricarboxylic acid (TCA) cycle and in the aerobic respiratory chains of eukaryotes and bacteria. Essential in this catalysis is the covalently-linked cofactor flavin adenine dinucleotide (FAD) in subunit1 (Sdh1) of the SDH enzyme complex. The mechanism of FAD insertion and covalent attachment to Sdh1 is unknown. Our working concept of this flavinylation process has relied mostly on foundational works from the 1990s and by applying the principles learned from other enzymes containing a similarly linked FAD. The discovery of the flavinylation factor Sdh5, however, has provided new insight into the possible mechanism associated with Sdh1 flavinylation. This review focuses on encapsulating prior and recent advances towards understanding the mechanism associated with flavinylation of Sdh1 and how this flavinylation process affects the overall assembly of SDH. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- Hyung J Kim
- Department of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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23
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Prokaryotic assembly factors for the attachment of flavin to complex II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:637-47. [PMID: 22985599 DOI: 10.1016/j.bbabio.2012.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/05/2012] [Accepted: 09/07/2012] [Indexed: 01/01/2023]
Abstract
Complex II (also known as Succinate dehydrogenase or Succinate-ubiquinone oxidoreductase) is an important respiratory enzyme that participates in both the tricarboxylic acid cycle and electron transport chain. Complex II consists of four subunits including a catalytic flavoprotein (SdhA), an iron-sulphur subunit (SdhB) and two hydrophobic membrane anchors (SdhC and SdhD). Complex II also contains a number of redox cofactors including haem, Fe-S clusters and FAD, which mediate electron transfer from succinate oxidation to the reduction of the mobile electron carrier ubiquinone. The flavin cofactor FAD is an important redox cofactor found in many proteins that participate in oxidation/reduction reactions. FAD is predominantly bound non-covalently to flavoproteins, with only a small percentage of flavoproteins, such as complex II, binding FAD covalently. Aside from a few examples, the mechanisms of flavin attachment have been a relatively unexplored area. This review will discuss the FAD cofactor and the mechanisms used by flavoproteins to covalently bind FAD. Particular focus is placed on the attachment of FAD to complex II with an emphasis on SdhE (a DUF339/SDH5 protein previously termed YgfY), the first protein identified as an assembly factor for FAD attachment to flavoproteins in prokaryotes. The molecular details of SdhE-dependent flavinylation of complex II are discussed and comparisons are made to known cofactor chaperones. Furthermore, an evolutionary hypothesis is proposed to explain the distribution of SdhE homologues in bacterial and eukaryotic species. Mechanisms for regulating SdhE function and how this may be linked to complex II function in different bacterial species are also discussed. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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24
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Wallner S, Winkler A, Riedl S, Dully C, Horvath S, Gruber K, Macheroux P. Catalytic and structural role of a conserved active site histidine in berberine bridge enzyme. Biochemistry 2012; 51:6139-47. [PMID: 22757961 PMCID: PMC3413249 DOI: 10.1021/bi300411n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Berberine bridge enzyme (BBE) is a paradigm for the class
of bicovalently
flavinylated oxidases, which catalyzes the oxidative cyclization of
(S)-reticuline to (S)-scoulerine.
His174 was identified as an important active site residue because
of its role in the stabilization of the reduced state of the flavin
cofactor. It is also strictly conserved in the family of BBE-like
oxidases. Here, we present a detailed biochemical and structural characterization
of a His174Ala variant supporting its importance during catalysis
and for the structural organization of the active site. Substantial
changes in all kinetic parameters and a decrease in midpoint potential
were observed for the BBE His174Ala variant protein. Moreover, the
crystal structure of the BBE His174Ala variant showed significant
structural rearrangements compared to wild-type enzyme. On the basis
of our findings, we propose that His174 is part of a hydrogen bonding
network that stabilizes the negative charge at the N1–C2=O
locus via interaction with the hydroxyl group at C2′ of the
ribityl side chain of the flavin cofactor. Hence, replacement of this
residue with alanine reduces the stabilizing effect for the transiently
formed negative charge and results in drastically decreased kinetic
parameters as well as a lower midpoint redox potential.
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Affiliation(s)
- Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
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25
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McNeil MB, Clulow JS, Wilf NM, Salmond GPC, Fineran PC. SdhE is a conserved protein required for flavinylation of succinate dehydrogenase in bacteria. J Biol Chem 2012; 287:18418-28. [PMID: 22474332 DOI: 10.1074/jbc.m111.293803] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conserved uncharacterized genes account for ~30% of genes in both eukaryotic and bacterial genomes and are predicted to encode what are often termed "conserved hypothetical proteins." Many of these proteins have a wide phylogenetic distribution and might play important roles in conserved cellular pathways. Using the bacterium Serratia as a model system, we have investigated two conserved uncharacterized proteins, YgfY (a DUF339 protein, renamed SdhE; succinate dehydrogenase protein E) and YgfX (a DUF1434 protein). SdhE was required for growth on succinate as a sole carbon source and for the function, but not stability, of succinate dehydrogenase, an important component of the electron transport chain and the tricarboxylic acid cycle. SdhE interacted with the flavoprotein SdhA, directly bound the flavin adenine dinucleotide co-factor, and was required for the flavinylation of SdhA. This is the first demonstration of a protein required for FAD incorporation in bacteria. Furthermore, the loss of SdhE was highly pleiotropic, suggesting that SdhE might flavinylate other flavoproteins. Our findings are of wide importance to central metabolism because SdhE homologues are present in α-, β-, and γ-proteobacteria and multiple eukaryotes, including humans and yeast.
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Affiliation(s)
- Matthew B McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
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26
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Winter RT, van den Berg TE, Colpa DI, van Bloois E, Fraaije MW. Functionalization of oxidases with peroxidase activity creates oxiperoxidases: a new breed of hybrid enzyme capable of cascade chemistry. Chembiochem 2011; 13:252-8. [PMID: 22213198 DOI: 10.1002/cbic.201100639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Indexed: 11/09/2022]
Abstract
The covalent flavoprotein alditol oxidase (AldO) from Streptomyces coelicolor A3(2) was endowed with an extra catalytic functionality by fusing it to a microperoxidase. Purification of the construct resulted in the isolation of a synthetic bifunctional enzyme that was both fully covalently flavinylated and heminylated: an oxiperoxidase. Characterization revealed that both oxidase and peroxidase functionalities were active, with the construct functioning as a single-component xylitol biosensor. In an attempt to reduce the size of the oxidase-peroxidase fusion, we replaced portions of the native AldO sequence with the bacterial cytochrome c CXXCH heme-binding motif. By mutating only three residues of the AldO protein we were able to create a functional oxidase-peroxidase hybrid.
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Affiliation(s)
- Remko T Winter
- Laboratory of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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27
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Kopacz MM, Rovida S, van Duijn E, Fraaije MW, Mattevi A. Structure-based redesign of cofactor binding in putrescine oxidase. Biochemistry 2011; 50:4209-17. [PMID: 21486042 DOI: 10.1021/bi200372u] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Putrescine oxidase (PuO) from Rhodococcus erythropolis is a soluble homodimeric flavoprotein, which oxidizes small aliphatic diamines. In this study, we report the crystal structures and cofactor binding properties of wild-type and mutant enzymes. From a structural viewpoint, PuO closely resembles the sequence-related human monoamine oxidases A and B. This similarity is striking in the flavin-binding site even if PuO does not covalently bind the cofactor as do the monoamine oxidases. A remarkable conserved feature is the cis peptide conformation of the Tyr residue whose conformation is important for substrate recognition in the active site cavity. The structure of PuO in complex with the reaction product reveals that Glu324 is crucial in recognizing the terminal amino group of the diamine substrate and explains the narrow substrate specificity of the enzyme. The structural analysis also provides clues for identification of residues that are responsible for the competitive binding of ADP versus FAD (~50% of wild-type PuO monomers isolated are occupied by ADP instead of FAD). By replacing Pro15, which is part of the dinucleotide-binding domain, enzyme preparations were obtained that are almost 100% in the FAD-bound form. Furthermore, mutants have been designed and prepared that form a covalent 8α-S-cysteinyl-FAD linkage. These data provide new insights into the molecular basis for substrate recognition in amine oxidases and demonstrate that engineering of flavoenzymes to introduce covalent linkage with the cofactor is a possible route to develop more stable protein molecules, better suited for biocatalytic purposes.
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Affiliation(s)
- Malgorzata M Kopacz
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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28
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Sucharitakul J, Wongnate T, Chaiyen P. Kinetic Isotope Effects on the Noncovalent Flavin Mutant Protein of Pyranose 2-Oxidase Reveal Insights into the Flavin Reduction Mechanism. Biochemistry 2010; 49:3753-65. [DOI: 10.1021/bi100187b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Patumwan, Bangkok 10330, Thailand
| | - Thanyaporn Wongnate
- Department of Biochemistry and Center of Excellence in Protein Structure and Function, 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, Bangkok 10400, Thailand
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29
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Heuts DPHM, Scrutton NS, McIntire WS, Fraaije MW. What's in a covalent bond? On the role and formation of covalently bound flavin cofactors. FEBS J 2009; 276:3405-27. [PMID: 19438712 DOI: 10.1111/j.1742-4658.2009.07053.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many enzymes use one or more cofactors, such as biotin, heme, or flavin. These cofactors may be bound to the enzyme in a noncovalent or covalent manner. Although most flavoproteins contain a noncovalently bound flavin cofactor (FMN or FAD), a large number have these cofactors covalently linked to the polypeptide chain. Most covalent flavin-protein linkages involve a single cofactor attachment via a histidyl, tyrosyl, cysteinyl or threonyl linkage. However, some flavoproteins contain a flavin that is tethered to two amino acids. In the last decade, many studies have focused on elucidating the mechanism(s) of covalent flavin incorporation (flavinylation) and the possible role(s) of covalent protein-flavin bonds. These endeavors have revealed that covalent flavinylation is a post-translational and self-catalytic process. This review presents an overview of the known types of covalent flavin bonds and the proposed mechanisms and roles of covalent flavinylation.
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Affiliation(s)
- Dominic P H M Heuts
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands
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30
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Grandori R, Santambrogio C, Brocca S, Invernizzi G, Lotti M. Electrospray-ionization mass spectrometry as a tool for fast screening of protein structural properties. Biotechnol J 2009; 4:73-87. [DOI: 10.1002/biot.200800250] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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