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Islam Z, Aldous N, Choi S, Schmidt F, Mifsud B, Abdelalim EM, Kolatkar PR. Flavin Adenine Dinucleotide (FAD) and Pyridoxal 5'-Phosphate (PLP) Bind to Sox9 and Alter the Expression of Key Pancreatic Progenitor Transcription Factors. Int J Mol Sci 2022; 23:ijms232214051. [PMID: 36430529 PMCID: PMC9694089 DOI: 10.3390/ijms232214051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 11/16/2022] Open
Abstract
Cofactor flavin adenine dinucleotide (FAD), a compound with flavin moiety and a derivative of riboflavin (vitamin B2), is shown to bind to Sox9 (a key transcription factor in early pancreatic development) and, subsequently, induce a large increase in markers of pancreatic development, including Ngn3 and PTF1a. Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, also binds to Sox9 and results in a similar increase in pancreatic development markers. Sox9 is known to be specifically important for pancreatic progenitors. Previously, there was no known link between FAD, PLP, or other co-factors and Sox9 for function. Thus, our findings show the mechanism by which FAD and PLP interact with Sox9 and result in the altered expression of pancreatic progenitor transcription factors involved in the pancreas development.
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Affiliation(s)
- Zeyaul Islam
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
| | - Noura Aldous
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
| | - Sunkyu Choi
- Proteomics Core, Weill Cornell Medicine, Doha P.O. Box 24144, Qatar
| | - Frank Schmidt
- Proteomics Core, Weill Cornell Medicine, Doha P.O. Box 24144, Qatar
| | - Borbala Mifsud
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
| | - Essam M. Abdelalim
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
| | - Prasanna R. Kolatkar
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha P.O. Box 34110, Qatar
- Correspondence: ; Tel.: +974-445-45889; Fax: +974-445-41770
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2
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The family of berberine bridge enzyme-like enzymes: A treasure-trove of oxidative reactions. Arch Biochem Biophys 2017; 632:88-103. [PMID: 28676375 DOI: 10.1016/j.abb.2017.06.023] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 12/18/2022]
Abstract
Biological oxidations form the basis of life on earth by utilizing organic compounds as electron donors to drive the generation of metabolic energy carriers, such as ATP. Oxidative reactions are also important for the biosynthesis of complex compounds, i.e. natural products such as alkaloids that provide vital benefits for organisms in all kingdoms of life. The vitamin B2-derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) enable an astonishingly diverse array of oxidative reactions that is based on the versatility of the redox-active isoalloxazine ring. The family of FAD-linked oxidases can be divided into subgroups depending on specific sequence features in an otherwise very similar structural context. The sub-family of berberine bridge enzyme (BBE)-like enzymes has recently attracted a lot of attention due to the challenging chemistry catalyzed by its members and the unique and unusual bi-covalent attachment of the FAD cofactor. This family is the focus of the present review highlighting recent advancements into the structural and functional aspects of members from bacteria, fungi and plants. In view of the unprecedented reaction catalyzed by the family's namesake, BBE from the California poppy, recent studies have provided further insights into nature's treasure chest of oxidative reactions.
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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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4
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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: 140] [Impact Index Per Article: 9.3] [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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5
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Huang CH, Winkler A, Chen CL, Lai WL, Tsai YC, Macheroux P, Liaw SH. Functional roles of the 6-S-cysteinyl, 8alpha-N1-histidyl FAD in glucooligosaccharide oxidase from Acremonium strictum. J Biol Chem 2008; 283:30990-6. [PMID: 18768475 DOI: 10.1074/jbc.m804331200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structure of glucooligosaccharide oxidase from Acremonium strictum was demonstrated to contain a bicovalent flavinylation, with the 6- and 8alpha-positions of the flavin isoalloxazine ring cross-linked to Cys(130) and His(70), respectively. The H70A and C130A single mutants still retain the covalent FAD, indicating that flavinylation at these two residues is independent. Both mutants exhibit a decreased midpoint potential of approximately +69 and +61 mV, respectively, compared with +126 mV for the wild type, and possess lower activities with k(cat) values reduced to approximately 2 and 5%, and the flavin reduction rate reduced to 0.6 and 14%. This indicates that both covalent linkages increase the flavin redox potential and alter the redox properties to promote catalytic efficiency. In addition, the isolated H70A/C130A double mutant does not contain FAD, and addition of exogenous FAD was not able to restore any detectable activity. This demonstrates that the covalent attachment is essential for the binding of the oxidized cofactor. Furthermore, the crystal structure of the C130A mutant displays conformational changes in several cofactor and substrate-interacting residues and hence provides direct evidence for novel functions of flavinylation in assistance of cofactor and substrate binding. Finally, the wild-type enzyme is more heat and guanidine HCl-resistant than the mutants. Therefore, the bicovalent flavin linkage not only tunes the redox potential and contributes to cofactor and substrate binding but also increases structural stability.
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Affiliation(s)
- Chun-Hsiang Huang
- Department of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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6
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Leferink NGH, Heuts DPHM, Fraaije MW, van Berkel WJH. The growing VAO flavoprotein family. Arch Biochem Biophys 2008; 474:292-301. [PMID: 18280246 DOI: 10.1016/j.abb.2008.01.027] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 01/28/2008] [Accepted: 01/30/2008] [Indexed: 11/17/2022]
Abstract
The VAO flavoprotein family is a rapidly growing family of oxidoreductases that favor the covalent binding of the FAD cofactor. In this review we report on the catalytic properties of some newly discovered VAO family members and their mode of flavin binding. Covalent binding of the flavin is a self-catalytic post-translational modification primarily taking place in oxidases. Covalent flavinylation increases the redox potential of the cofactor and thus its oxidation power. Recent findings have revealed that some members of the VAO family anchor the flavin via a dual covalent linkage (6-S-cysteinyl-8alpha-N1-histidyl FAD). Some VAO-type aldonolactone oxidoreductases favor the non-covalent binding of the flavin cofactor. These enzymes act as dehydrogenases, using cytochrome c as electron acceptor.
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Affiliation(s)
- Nicole G H Leferink
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
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7
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Lee MH, Lai WL, Lin SF, Hsu CS, Liaw SH, Tsai YC. Structural characterization of glucooligosaccharide oxidase from Acremonium strictum. Appl Environ Microbiol 2006; 71:8881-7. [PMID: 16332885 PMCID: PMC1317382 DOI: 10.1128/aem.71.12.8881-8887.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucooligosaccharide oxidase from Acremonium strictum was screened for potential applications in oligosaccharide acid production and carbohydrate detection. This protein is a unique covalent flavoenzyme which catalyzes the oxidation of a variety of carbohydrates with high selectivity for cello- and maltooligosaccharides. Kinetic measurements suggested that this enzyme possesses an open carbohydrate-binding groove, which is mainly composed of two glucosyl-binding subsites. The encoding gene was subsequently cloned, and one intron was detected in the genomic DNA. Large amounts of active enzymes were expressed in Pichia pastoris, with a yield of 300 mg per liter medium. The protein was predicted to share structural homology with plant cytokinin dehydrogenase and related flavoproteins that share a conserved flavin adenine dinucleotide (FAD)-binding domain. The closest sequence matches are those of plant berberine bridge enzyme-like proteins, particularly the characteristic flavinylation site. Unexpectedly, mutation of the putative FAD-attaching residue, H70, to alanine, serine, cysteine, and tyrosine did not abolish the covalent FAD linkage and had little effect on the Km. Instead, the variants displayed kcat values that were 50- to 600-fold lower, indicating that H70 is crucial for efficient redox catalysis, perhaps through modulation of the oxidative power of the flavin.
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Affiliation(s)
- Meng-Hwan Lee
- Institute of Biochemistry, National Yang-Ming University, 155, Sec. 2, Li-Nong St., Pei-Tou, Taipei 11221, Taiwan
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8
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Sandu C, Chiribau CB, Sachelaru P, Brandsch R. Plasmids for nicotine-dependent and -independent gene expression in Arthrobacter nicotinovorans and other arthrobacter species. Appl Environ Microbiol 2006; 71:8920-4. [PMID: 16332890 PMCID: PMC1317448 DOI: 10.1128/aem.71.12.8920-8924.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The first inducible Arthrobacter overexpression system, based on the promoter/operator and the repressor of the 6-D-hydroxynicotine oxidase gene of Arthrobacter nicotinovorans, is described here. Nicotine-dependent overproduction and affinity purification of recombinant proteins are presented. The system will allow the production of complex enzymes and genetic complementation studies in Arthrobacter species.
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Affiliation(s)
- Cristinel Sandu
- Institute of Biochemistry and Molecular Biology, University of Freiburg, Hermann Herder Str. 7, 79104 Freiburg, Germany.
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9
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Sirikantaramas S, Morimoto S, Shoyama Y, Ishikawa Y, Wada Y, Shoyama Y, Taura F. The gene controlling marijuana psychoactivity: molecular cloning and heterologous expression of Delta1-tetrahydrocannabinolic acid synthase from Cannabis sativa L. J Biol Chem 2004; 279:39767-74. [PMID: 15190053 DOI: 10.1074/jbc.m403693200] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Delta(1)-tetrahydrocannabinolic acid (THCA) synthase is the enzyme that catalyzes oxidative cyclization of cannabigerolic acid into THCA, the precursor of Delta(1)-tetrahydrocannabinol. We cloned a novel cDNA (GenBank trade mark accession number AB057805) encoding THCA synthase by reverse transcription and polymerase chain reactions from rapidly expanding leaves of Cannabis sativa. This gene consists of a 1635-nucleotide open reading frame, encoding a 545-amino acid polypeptide of which the first 28 amino acid residues constitute the signal peptide. The predicted molecular weight of the 517-amino acid mature polypeptide is 58,597 Da. Interestingly, the deduced amino acid sequence exhibited high homology to berberine bridge enzyme from Eschscholtzia californica, which is involved in alkaloid biosynthesis. The liquid culture of transgenic tobacco hairy roots harboring the cDNA produced THCA upon feeding of cannabigerolic acid, demonstrating unequivocally that this gene encodes an active THCA synthase. Overexpression of the recombinant THCA synthase was achieved using a baculovirus-insect expression system. The purified recombinant enzyme contained covalently attached FAD cofactor at a molar ratio of FAD to protein of 1:1. The mutant enzyme constructed by changing His-114 of the wild-type enzyme to Ala-114 exhibited neither absorption characteristics of flavoproteins nor THCA synthase activity. Thus, we concluded that the FAD binding residue is His-114 and that the THCA synthase reaction is FAD-dependent. This is the first report on molecular characterization of an enzyme specific to cannabinoid biosynthesis.
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10
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Fraaije MW, van den Heuvel RH, Mattevi A, van Berkel WJ. Covalent flavinylation enhances the oxidative power of vanillyl-alcohol oxidase. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1177(02)00133-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Edmondson DE, Newton-Vinson P. The covalent FAD of monoamine oxidase: structural and functional role and mechanism of the flavinylation reaction. Antioxid Redox Signal 2001; 3:789-806. [PMID: 11761328 DOI: 10.1089/15230860152664984] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The family of flavoenzymes in which the flavin coenzyme redox cofactor is covalently attached to the protein through an amino acid side chain is covered in this review. Flavin-protein covalent linkages have been shown to exist through each of five known linkages: (a) 8alpha-N(3)-histidyl, (b) 8alpha-N(1)-histidyl, (c) 8alpha-S-cysteinyl, (d) 8alpha-O-tyrosyl, or (e) 6-S-cysteinyl with the flavin existing at either the flavin mononucleotide or flavin adenine dinucleotide (FAD) levels. This class of enzymes is widely distributed in diverse biological systems and catalyzes a variety of enzymatic reactions. Current knowledge on the mechanism of covalent flavin attachment is discussed based on studies on the 8alpha-S-cysteinylFAD of monoamine oxidases A and B, as well as studies on other flavoenzymes. The evidence supports an autocatalytic quinone-methide mechanism of protein flavinylation. Proposals to explain the structural and mechanistic advantages of a covalent flavin linkage in flavoenzymes are presented. It is concluded that multiple factors are involved and include: (a) stabilization of the apoenzyme structure, (b) steric alignment of the cofactor in the active site to facilitate catalysis, and (c) modulation of the redox potential of the covalent flavin through electronic effects of 8alpha-substitution.
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Affiliation(s)
- D E Edmondson
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.
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12
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Fraaije MW, van den Heuvel RH, van Berkel WJ, Mattevi A. Covalent flavinylation is essential for efficient redox catalysis in vanillyl-alcohol oxidase. J Biol Chem 1999; 274:35514-20. [PMID: 10585424 DOI: 10.1074/jbc.274.50.35514] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By mutating the target residue of covalent flavinylation in vanillyl-alcohol oxidase, the functional role of the histidyl-FAD bond was studied. Three His(422) mutants (H422A, H422T, and H422C) were purified, which all contained tightly but noncovalently bound FAD. Steady state kinetics revealed that the mutants have retained enzyme activity, although the turnover rates have decreased by 1 order of magnitude. Stopped-flow analysis showed that the H422A mutant is still able to form a stable binary complex of reduced enzyme and a quinone methide product intermediate, a crucial step during vanillyl-alcohol oxidase-mediated catalysis. The only significant change in the catalytic cycle of the H422A mutant is a marked decrease in reduction rate. Redox potentials of both wild type and H422A vanillyl-alcohol oxidase have been determined. During reduction of H422A, a large portion of the neutral flavin semiquinone is observed. Using suitable reference dyes, the redox potentials for the two one-electron couples have been determined: -17 and -113 mV. Reduction of wild type enzyme did not result in any formation of flavin semiquinone and revealed a remarkably high redox potential of +55 mV. The marked decrease in redox potential caused by the missing covalent histidyl-FAD bond is reflected in the reduced rate of substrate-mediated flavin reduction limiting the turnover rate. Elucidation of the crystal structure of the H422A mutant established that deletion of the histidyl-FAD bond did not result in any significant structural changes. These results clearly indicate that covalent interaction of the isoalloxazine ring with the protein moiety can markedly increase the redox potential of the flavin cofactor, thereby facilitating redox catalysis. Thus, formation of a histidyl-FAD bond in specific flavoenzymes might have evolved as a way to contribute to the enhancement of their oxidative power.
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Affiliation(s)
- M W Fraaije
- Department of Genetics, University of Pavia, via Abbiategrasso 207, 27100 Pavia, Italy.
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13
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Mewies M, McIntire WS, Scrutton NS. Covalent attachment of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) to enzymes: the current state of affairs. Protein Sci 1998; 7:7-20. [PMID: 9514256 PMCID: PMC2143808 DOI: 10.1002/pro.5560070102] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The first identified covalent flavoprotein, a component of mammalian succinate dehydrogenase, was reported 42 years ago. Since that time, more than 20 covalent flavoenzymes have been described, each possessing one of five modes of FAD or FMN linkage to protein. Despite the early identification of covalent flavoproteins, the mechanisms of covalent bond formation and the roles of the covalent links are only recently being appreciated. The main focus of this review is, therefore, one of mechanism and function, in addition to surveying the types of linkage observed and the methods employed for their identification. Case studies are presented for a variety of covalent flavoenzymes, from which general findings are beginning to emerge.
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Affiliation(s)
- M Mewies
- Department of Biochemistry, University of Leicester, UK
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14
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Affiliation(s)
- K Decker
- Institute of Biochemistry and Molecular Biology, Albert-Ludwig University, Freiburg i. Br., Germany
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15
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Stoltz M, Rassow J, Bückmann AF, Brandsch R. Covalent attachment of FAD derivatives to a fusion protein consisting of 6-hydroxy-D-nicotine oxidase and a mitochondrial presequence. Folding, enzyme activity, and import of the modified protein into yeast mitochondria. J Biol Chem 1996; 271:25208-12. [PMID: 8810280 DOI: 10.1074/jbc.271.41.25208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Autoflavinylation of 6-hydroxy-D-nicotine oxidase (6-HDNO) was successfully employed to modify the protein covalently with FAD derivatives. The model compounds N6-(2-aminoethyl)-FAD and N6-(6-carboxyhexyl)-FAD were spontaneously bound to a fusion protein consisting of the mitochondrial targeting sequence of Neurospora crassa F0-ATPase subunit 9 (Su9) attached to 6-HDNO. When translated in the rabbit reticulocyte lysate, Su9-6-HDNO was in the trypsin-sensitive apoenzyme form; when translated in the presence of flavins it adopted a trypsin-resistant conformation characteristic of the 6-HDNO holoenzyme. With flavin derivatives, Su9-6-HDNO exhibited approximately 50% of the 6-HDNO activity observed with FAD. The covalently modified Su9-6-HDNO was imported into Saccharomyces cerevisiae mitochondria with an efficiency equal to that of the apoenzyme. Apparently the increase in size and charge of the FAD moiety did not hamper translocation across the mitochondrial membranes. Yeast mutant ssc1-2 mitochondria deficient in mtHsp70 unfoldase activity imported the flavinylated Su9-6-HDNO protein. In mutant ssc1-3 mitochondria deficient in both mtHsp70 unfoldase and translocase activity Su9-6-HDNO was trapped as translocation intermediate; the Su9 presequence was passed to the matrix where it was proteolytically cleaved by the mitochondrial processing peptidase; (MPP); the translocation-arrested 6-HDNO moiety adopted a trypsin-sensitive conformation. Our results indicate that unfolding of the FAD-stabilized flavin-binding domain of 6-HDNO in passage through the mitochondrial general insertion pore does not require the activity of mtHsp70.
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Affiliation(s)
- M Stoltz
- Institut für Biochemie und Molekularbiologie, D-79104 Freiburg, Germany
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16
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Stoltz M, Henninger HP, Brandsch R. The design of an alternative, covalently flavinylated 6-hydroxy-D-nicotine oxidase by replacing the FAD-binding histidine by cysteine and reconstitution of the holoenzyme with 8-(methylsulfonyl)FAD. FEBS Lett 1996; 386:194-6. [PMID: 8647280 DOI: 10.1016/0014-5793(96)00438-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The cofactor of several flavoenzymes is autocatalytically bound to the polypeptide via a histidyl(N3)-(8alpha)-FAD linkage which makes the generation of apoenzyme difficult. We introduced an alternative covalent protein-FAD bond at the active site of 6-hydroxy-D-nicotine oxidase (6HDNO) by replacing the FAD-binding histidine with cysteine. The resulting mutant enzyme was expressed with noncovalently attached cofactor. Incubation with 8-(methylsulfonyl)FAD, and less efficiently with 8-chloro-FAD, resulted in the spontaneous replacement of the noncovalently bound FAD by the flavin derivative and the formation of an 8-(N-acetylcysteinyl)FAD linkage. The flavinylated 6HDNO.cys exhibited close to wild-type activity levels. This strategy may be generally applicable to the attachment of artificially designed flavin derivatives to the active site of covalently flavinylated enzymes.
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Affiliation(s)
- M Stoltz
- Institut für Biochemie und Molekularbiologie, Frieburg, Germany
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17
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Mushegian AR, Koonin EV. A putative FAD-binding domain in a distinct group of oxidases including a protein involved in plant development. Protein Sci 1995; 4:1243-4. [PMID: 7549889 PMCID: PMC2143151 DOI: 10.1002/pro.5560040623] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Using methods for database screening with individual protein sequences and alignment blocks, a conserved domain is delineated in a group of proteins including several FAD-dependent oxidases. Two motifs within this domain resemble phosphate-binding loops and may be directly involved in FAD binding. These motifs can be readily distinguished from previously described nucleotide-binding sites using a method for database screening with position-dependent weight matrices derived from alignment blocks. Unexpectedly, this group of known and predicted FAD-dependent oxidases includes the product of the DIMINUTO gene, which is involved in Arabidopsis development, and its homologues from man and Mycobacterium leprae.
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Affiliation(s)
- A R Mushegian
- Department of Microbiology, University of Washington, Seattle 98195, USA
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18
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Robinson KM, Lemire BD. Flavinylation of succinate: ubiquinone oxidoreductase from Saccharomyces cerevisiae. Methods Enzymol 1995; 260:34-51. [PMID: 8592458 DOI: 10.1016/0076-6879(95)60128-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- K M Robinson
- Medical Research Council of Canada Group in the Molecular Biology of Membranes, Department of Biochemistry, University of Alberta, Edmonton, Canada
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19
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Assembly of redox centers in the trimethylamine dehydrogenase of bacterium W3A1. Properties of the wild-type enzyme and a C30A mutant expressed from a cloned gene in Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36739-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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20
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Lysine can replace arginine 67 in the mediation of covalent attachment of FAD to histidine 71 of 6-hydroxy-D-nicotine oxidase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38220-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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