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Nguyen D, Vigil W, Niks D, Hille R. The rapid-reaction kinetics of an electron-bifurcating flavoprotein, the crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase EtfAB:bcd. J Biol Chem 2024; 300:107745. [PMID: 39236874 DOI: 10.1016/j.jbc.2024.107745] [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: 06/06/2024] [Revised: 08/14/2024] [Accepted: 08/27/2024] [Indexed: 09/07/2024] Open
Abstract
We have investigated the kinetic behavior of the electron-bifurcating crotonyl-CoA-dependent NADH: ferredoxin oxidoreductase EtfAB:bcd from Megasphaera elsdenii. The overall behavior of the complex in both the reductive and the oxidative half-reactions is consistent with that previously determined for the individual EtfAB and bcd components. This includes an uncrossing of the half-potentials of the bifurcating flavin of the EtfAB component in the course of ferredoxin-reducing catalysis, ionization of the bcd flavin semiquinone and the appearance of a charge transfer complex upon binding of the high potential acceptor crotonyl-CoA. The observed rapid-reaction rates of ferredoxin reduction are independent of [NADH], [crotonyl-CoA], and [ferredoxin], with an observed rate of ∼0.2 s-1, consistent with the observed steady-state kinetics. In enzyme-monitored turnover experiments, an approach to steady-state where the complex's flavins become reduced but no ferredoxin is generated is followed by a steady-state phase characterized by extensive ferredoxin reduction but little change in overall levels of flavin reduction. The approach to the steady-state phase can be eliminated by prior reduction of the complex, in which case there is no lag in the onset of ferredoxin reduction; this is consistent with the et FAD needing to be reduced to the level of the (anionic) semiquinone for bifurcation and concomitant ferredoxin reduction to occur. Single-turnover experiments support this conclusion, with the accumulation of the anionic semiquinone of the et FAD apparently required to prime the system for subsequent bifurcation and ferredoxin reduction.
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Affiliation(s)
- Derek Nguyen
- Department of Biochemistry, The University of California, Riverside, California, USA
| | - Wayne Vigil
- Department of Biochemistry, The University of California, Riverside, California, USA
| | - Dimitri Niks
- Department of Biochemistry, The University of California, Riverside, California, USA
| | - Russ Hille
- Department of Biochemistry, The University of California, Riverside, California, USA.
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2
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Narayanan B, Xia C, McAndrew R, Shen AL, Kim JJP. Structural basis for expanded substrate specificities of human long chain acyl-CoA dehydrogenase and related acyl-CoA dehydrogenases. Sci Rep 2024; 14:12976. [PMID: 38839792 PMCID: PMC11153573 DOI: 10.1038/s41598-024-63027-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Crystal structures of human long-chain acyl-CoA dehydrogenase (LCAD) and the catalytically inactive Glu291Gln mutant, have been determined. These structures suggest that LCAD harbors functions beyond its historically defined role in mitochondrial β-oxidation of long and medium-chain fatty acids. LCAD is a homotetramer containing one FAD per 43 kDa subunit with Glu291 as the catalytic base. The substrate binding cavity of LCAD reveals key differences which makes it specific for longer and branched chain substrates. The presence of Pro132 near the start of the E helix leads to helix unwinding that, together with adjacent smaller residues, permits binding of bulky substrates such as 3α, 7α, l2α-trihydroxy-5β-cholestan-26-oyl-CoA. This structural element is also utilized by ACAD11, a eucaryotic ACAD of unknown function, as well as bacterial ACADs known to metabolize sterol substrates. Sequence comparison suggests that ACAD10, another ACAD of unknown function, may also share this substrate specificity. These results suggest that LCAD, ACAD10, ACAD11 constitute a distinct class of eucaryotic acyl CoA dehydrogenases.
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Affiliation(s)
- Beena Narayanan
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Chuanwu Xia
- Department of Chemistry and Biochemistry, College of Arts and Sciences, University of North Florida, Jacksonville, FL, 32224, USA
| | - Ryan McAndrew
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94740, USA
| | - Anna L Shen
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jung-Ja P Kim
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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3
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Narayanan B, Xia C, McAndrew R, Shen AL, Kim JJP. Structural Basis for Expanded Substrate Speci ficities of Human Long Chain Acyl-CoA Dehydrogenase and Related Acyl- CoA Dehydrogenases. RESEARCH SQUARE 2024:rs.3.rs-3980524. [PMID: 38464032 PMCID: PMC10925408 DOI: 10.21203/rs.3.rs-3980524/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Crystal structures of human long-chain acyl-CoA dehydrogenase (LCAD) and the E291Q mutant, have been determined. These structures suggest that LCAD harbors functions beyond its historically defined role in mitochondrial β-oxidation of long and medium-chain fatty acids. LCAD is a homotetramer containing one FAD per 43kDa subunit with Glu291 as the catalytic base. The substrate binding cavity of LCAD reveals key differences which makes it specific for longer and branched chain substrates. The presence of Pro132 near the start of the E helix leads to helix unwinding that, together with adjacent smaller residues, permits binding of bulky substrates such as 3α, 7α, l2α-trihydroxy-5β-cholestan-26-oyl-CoA. This structural element is also utilized by ACAD11, a eucaryotic ACAD of unknown function, as well as bacterial ACADs known to metabolize sterol substrates. Sequence comparison suggests that ACAD10, another ACAD of unknown function, may also share this substrate specificity. These results suggest that LCAD, ACAD10, ACAD11 constitute a distinct class of eucaryotic acyl CoA dehydrogenases.
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4
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Gnaiger E. Complex II ambiguities-FADH 2 in the electron transfer system. J Biol Chem 2024; 300:105470. [PMID: 38118236 PMCID: PMC10772739 DOI: 10.1016/j.jbc.2023.105470] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/01/2023] [Accepted: 11/06/2023] [Indexed: 12/22/2023] Open
Abstract
The prevailing notion that reduced cofactors NADH and FADH2 transfer electrons from the tricarboxylic acid cycle to the mitochondrial electron transfer system creates ambiguities regarding respiratory Complex II (CII). CII is the only membrane-bound enzyme in the tricarboxylic acid cycle and is part of the electron transfer system of the mitochondrial inner membrane feeding electrons into the coenzyme Q-junction. The succinate dehydrogenase subunit SDHA of CII oxidizes succinate and reduces the covalently bound prosthetic group FAD to FADH2 in the canonical forward tricarboxylic acid cycle. However, several graphical representations of the electron transfer system depict FADH2 in the mitochondrial matrix as a substrate to be oxidized by CII. This leads to the false conclusion that FADH2 from the β-oxidation cycle in fatty acid oxidation feeds electrons into CII. In reality, dehydrogenases of fatty acid oxidation channel electrons to the Q-junction but not through CII. The ambiguities surrounding Complex II in the literature and educational resources call for quality control, to secure scientific standards in current communications of bioenergetics, and ultimately support adequate clinical applications. This review aims to raise awareness of the inherent ambiguity crisis, complementing efforts to address the well-acknowledged issues of credibility and reproducibility.
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Szrok-Jurga S, Czumaj A, Turyn J, Hebanowska A, Swierczynski J, Sledzinski T, Stelmanska E. The Physiological and Pathological Role of Acyl-CoA Oxidation. Int J Mol Sci 2023; 24:14857. [PMID: 37834305 PMCID: PMC10573383 DOI: 10.3390/ijms241914857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 10/15/2023] Open
Abstract
Fatty acid metabolism, including β-oxidation (βOX), plays an important role in human physiology and pathology. βOX is an essential process in the energy metabolism of most human cells. Moreover, βOX is also the source of acetyl-CoA, the substrate for (a) ketone bodies synthesis, (b) cholesterol synthesis, (c) phase II detoxication, (d) protein acetylation, and (d) the synthesis of many other compounds, including N-acetylglutamate-an important regulator of urea synthesis. This review describes the current knowledge on the importance of the mitochondrial and peroxisomal βOX in various organs, including the liver, heart, kidney, lung, gastrointestinal tract, peripheral white blood cells, and other cells. In addition, the diseases associated with a disturbance of fatty acid oxidation (FAO) in the liver, heart, kidney, lung, alimentary tract, and other organs or cells are presented. Special attention was paid to abnormalities of FAO in cancer cells and the diseases caused by mutations in gene-encoding enzymes involved in FAO. Finally, issues related to α- and ω- fatty acid oxidation are discussed.
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Affiliation(s)
- Sylwia Szrok-Jurga
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Aleksandra Czumaj
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdansk, 80-211 Gdansk, Poland;
| | - Jacek Turyn
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Areta Hebanowska
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
| | - Julian Swierczynski
- Institue of Nursing and Medical Rescue, State University of Applied Sciences in Koszalin, 75-582 Koszalin, Poland;
| | - Tomasz Sledzinski
- Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Medical University of Gdansk, 80-211 Gdansk, Poland;
| | - Ewa Stelmanska
- Department of Biochemistry, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (S.S.-J.); (J.T.); (A.H.)
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6
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Madeira CA, Anselmo C, Costa JM, Bonito CA, Ferreira RJ, Santos DJVA, Wanders RJ, Vicente JB, Ventura FV, Leandro P. Functional and structural impact of 10 ACADM missense mutations on human medium chain acyl-Coa dehydrogenase. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166766. [PMID: 37257730 DOI: 10.1016/j.bbadis.2023.166766] [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: 02/06/2023] [Revised: 05/10/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023]
Abstract
Medium chain acyl-CoA dehydrogenase (MCAD) deficiency (MCADD) is associated with ACADM gene mutations, leading to an impaired function and/or structure of MCAD. Importantly, after import into the mitochondria, MCAD must incorporate a molecule of flavin adenine dinucleotide (FAD) per subunit and assemble into tetramers. However, the effect of MCAD amino acid substitutions on FAD incorporation has not been investigated. Herein, the commonest MCAD variant (p.K304E) and 11 additional rare variants (p.Y48C, p.R55G, p.A88P, p.Y133C, p.A140T, p.D143V, p.G224R, p.L238F, p.V264I, p.Y372N, and p.G377V) were functionally and structurally characterized. Half of the studied variants presented a FAD content <65 % compared to the wild-type. Most of them were recovered as tetramers, except the p.Y372N (mainly as dimers). No correlation was found between the levels of tetramers and FAD content. However, a correlation between FAD content and the cofactor's affinity, proteolytic stability, thermostability, and thermal inactivation was established. We showed that the studied amino acid changes in MCAD may alter the substrate chain-length dependence and the interaction with electron-transferring-flavoprotein (ETF) necessary for a proper functioning electron transfer thus adding additional layers of complexity to the pathological effect of ACADM missense mutations. Although the majority of the variant MCADs presented an impaired capacity to retain FAD during their synthesis, some of them were structurally rescued by cofactor supplementation, suggesting that in the mitochondrial environment the levels and activity of those variants may be dependent of FAD's availability thus contributing for the heterogeneity of the MCADD phenotype found in patients presenting the same genotype.
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Affiliation(s)
- Catarina A Madeira
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Carolina Anselmo
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - João M Costa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cátia A Bonito
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | | | - Daniel J V A Santos
- LAQV@REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal; Center for Research in Biosciences & Health Technologies (CBIOS), Universidade Lusófona de Humanidades e Tecnologias, Lisboa, Portugal
| | - Ronald J Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Centers-University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
| | - Fátima V Ventura
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
| | - Paula Leandro
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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Falnes PØ, Małecki JM, Herrera MC, Bengtsen M, Davydova E. Human seven-β-strand (METTL) methyltransferases - conquering the universe of protein lysine methylation. J Biol Chem 2023; 299:104661. [PMID: 36997089 DOI: 10.1016/j.jbc.2023.104661] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
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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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Tummolo A, Leone P, Tolomeo M, Solito R, Mattiuzzo M, Lepri FR, Lorè T, Cardinali R, De Giovanni D, Simonetti S, Barile M. Combined isobutyryl-CoA and multiple acyl-CoA dehydrogenase deficiency in a boy with altered riboflavin homeostasis. JIMD Rep 2022; 63:276-291. [PMID: 35822092 PMCID: PMC9259400 DOI: 10.1002/jmd2.12292] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 11/24/2022] Open
Abstract
In this report, we describe the case of an 11-year-old boy, who came to our attention for myalgia and muscle weakness, associated with inappetence and vomiting. Hypertransaminasemia was also noted, with ultrasound evidence of hepatomegaly. Biochemical investigations revealed acylcarnitine and organic acid profiles resembling those seen in MADD, that is, multiple acyl-CoA dehydrogenase deficiencies (OMIM #231680) a rare inherited disorder of fatty acids, amino acids, and choline metabolism. The patient carried a single pathogenetic variant in the ETFDH gene (c.524G>A, p.Arg175His) and no pathogenetic variant in the riboflavin (Rf) homeostasis related genes (SLC52A1, SLC52A2, SLC52A3, SLC25A32, FLAD1). Instead, compound heterozygosity was found in the ACAD8 gene (c.512C>G, p.Ser171Cys; c.822C>A, p.Asn274Lys), coding for isobutyryl-CoA dehydrogenase (IBD), whose pathogenic variants are associated to IBD deficiency (OMIM #611283), a rare autosomal recessive disorder of valine catabolism. The c.822C>A was never previously described in a patient. Subsequent further analyses of Rf homeostasis showed reduced levels of flavins in plasma and altered FAD-dependent enzymatic activities in erythrocytes, as well as a significant reduction in the level of the plasma membrane Rf transporter 2 in erythrocytes. The observed Rf/flavin scarcity in this patient, possibly associated with a decreased ETF:QO efficiency might be responsible for the observed MADD-like phenotype. The patient's clinical picture improved after supplementation of Rf, l-carnitine, Coenzyme Q10, and also 3OH-butyrate. This report demonstrates that, even in the absence of genetic defects in genes involved in Rf homeostasis, further targeted molecular analysis may reveal secondary and possibly treatable biochemical alterations in this pattern.
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Affiliation(s)
- Albina Tummolo
- Metabolic Diseases and Clinical Genetics UnitChildren's Hospital “Giovanni XXIII”BariItaly
| | - Piero Leone
- Department of Biosciences, Biotechnology and BiopharmaceuticsUniversity of Bari “A. Moro”BariItaly
| | - Maria Tolomeo
- Department of Biosciences, Biotechnology and BiopharmaceuticsUniversity of Bari “A. Moro”BariItaly
| | - Rita Solito
- Department of Biosciences, Biotechnology and BiopharmaceuticsUniversity of Bari “A. Moro”BariItaly
| | - Matteo Mattiuzzo
- Laboratory of Medical GeneticsTranslational Cytogenomics Research Unit, Bambino Gesù Children HospitalRomeItaly
| | - Francesca Romana Lepri
- Laboratory of Medical GeneticsTranslational Cytogenomics Research Unit, Bambino Gesù Children HospitalRomeItaly
| | - Tania Lorè
- Regional Centre for Neonatal ScreeningChildren's Hospital “Giovanni XXIII”BariItaly
| | - Roberta Cardinali
- Regional Centre for Neonatal ScreeningChildren's Hospital “Giovanni XXIII”BariItaly
| | - Donatella De Giovanni
- Metabolic Diseases and Clinical Genetics UnitChildren's Hospital “Giovanni XXIII”BariItaly
| | - Simonetta Simonetti
- Regional Centre for Neonatal ScreeningChildren's Hospital “Giovanni XXIII”BariItaly
| | - Maria Barile
- Department of Biosciences, Biotechnology and BiopharmaceuticsUniversity of Bari “A. Moro”BariItaly
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Małecki JM, Davydova E, Falnes PØ. Protein methylation in mitochondria. J Biol Chem 2022; 298:101791. [PMID: 35247388 PMCID: PMC9006661 DOI: 10.1016/j.jbc.2022.101791] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/15/2022] Open
Abstract
Many proteins are modified by posttranslational methylation, introduced by a number of methyltransferases (MTases). Protein methylation plays important roles in modulating protein function and thus in optimizing and regulating cellular and physiological processes. Research has mainly focused on nuclear and cytosolic protein methylation, but it has been known for many years that also mitochondrial proteins are methylated. During the last decade, significant progress has been made on identifying the MTases responsible for mitochondrial protein methylation and addressing its functional significance. In particular, several novel human MTases have been uncovered that methylate lysine, arginine, histidine, and glutamine residues in various mitochondrial substrates. Several of these substrates are key components of the bioenergetics machinery, e.g., respiratory Complex I, citrate synthase, and the ATP synthase. In the present review, we report the status of the field of mitochondrial protein methylation, with a particular emphasis on recently discovered human MTases. We also discuss evolutionary aspects and functional significance of mitochondrial protein methylation and present an outlook for this emergent research field.
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Affiliation(s)
- Jędrzej M Małecki
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway.
| | - Erna Davydova
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Pål Ø Falnes
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway.
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Mohamed-Raseek N, Miller AF. Contrasting roles for two conserved arginines: stabilizing flavin semiquinone or quaternary structure, in bifurcating electron transfer flavoproteins. J Biol Chem 2022; 298:101733. [PMID: 35176283 PMCID: PMC8958531 DOI: 10.1016/j.jbc.2022.101733] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 01/02/2023] Open
Abstract
Bifurcating electron transfer flavoproteins (Bf ETFs) are important redox enzymes that contain two flavin adenine dinucleotide (FAD) cofactors, with contrasting reactivities and complementary roles in electron bifurcation. However, for both the “electron transfer” (ET) and the “bifurcating” (Bf) FADs, the only charged amino acid within 5 Å of the flavin is a conserved arginine (Arg) residue. To understand how the two sites produce different reactivities utilizing the same residue, we investigated the consequences of replacing each of the Arg residues with lysine, glutamine, histidine, or alanine. We show that absence of a positive charge in the ET site diminishes accumulation of the anionic semiquinone (ASQ) that enables the ET flavin to act as a single electron carrier, due to depression of the oxidized versus. ASQ reduction midpoint potential, E°OX/ASQ. Perturbation of the ET site also affected the remote Bf site, whereas abrogation of Bf FAD binding accelerated chemical modification of the ET flavin. In the Bf site, removal of the positive charge impaired binding of FAD or AMP, resulting in unstable protein. Based on pH dependence, we propose that the Bf site Arg interacts with the phosphate(s) of Bf FAD or AMP, bridging the domain interface via a conserved peptide loop (“zipper”) and favoring nucleotide binding. We further propose a model that rationalizes conservation of the Bf site Arg even in non-Bf ETFs, as well as AMP's stabilizing role in the latter, and provides a mechanism for coupling Bf flavin redox changes to domain-scale motion.
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12
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Kung JW, Meier AK, Willistein M, Weidenweber S, Demmer U, Ermler U, Boll M. Structural Basis of Cyclic 1,3-Diene Forming Acyl-Coenzyme A Dehydrogenases. Chembiochem 2021; 22:3173-3177. [PMID: 34555236 PMCID: PMC9293079 DOI: 10.1002/cbic.202100421] [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: 08/16/2021] [Revised: 09/15/2021] [Indexed: 11/20/2022]
Abstract
The biologically important, FAD‐containing acyl‐coenzyme A (CoA) dehydrogenases (ACAD) usually catalyze the anti‐1,2‐elimination of a proton and a hydride of aliphatic CoA thioesters. Here, we report on the structure and function of an ACAD from anaerobic bacteria catalyzing the unprecedented 1,4‐elimination at C3 and C6 of cyclohex‐1‐ene‐1‐carboxyl‐CoA (Ch1CoA) to cyclohex‐1,5‐diene‐1‐carboxyl‐CoA (Ch1,5CoA) and at C3 and C4 of the latter to benzoyl‐CoA. Based on high‐resolution Ch1CoA dehydrogenase crystal structures, the unorthodox reactivity is explained by the presence of a catalytic aspartate base (D91) at C3, and by eliminating the catalytic glutamate base at C1. Moreover, C6 of Ch1CoA and C4 of Ch1,5CoA are positioned towards FAD‐N5 to favor the biologically relevant C3,C6‐ over the C3,C4‐dehydrogenation activity. The C1,C2‐dehydrogenation activity was regained by structure‐inspired amino acid exchanges. The results provide the structural rationale for the extended catalytic repertoire of ACADs and offer previously unknown biocatalytic options for the synthesis of cyclic 1,3‐diene building blocks.
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Affiliation(s)
- Johannes W Kung
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Anne-Katrin Meier
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Max Willistein
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Sina Weidenweber
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Ulrike Demmer
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Ulrich Ermler
- Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt, Germany
| | - Matthias Boll
- Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
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13
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D'Annibale OM, Koppes EA, Alodaib AN, Kochersperger C, Karunanidhi A, Mohsen AW, Vockley J. Characterization of variants of uncertain significance in isovaleryl-CoA dehydrogenase identified through newborn screening: An approach for faster analysis. Mol Genet Metab 2021; 134:29-36. [PMID: 34535384 PMCID: PMC8578405 DOI: 10.1016/j.ymgme.2021.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Clinical standard of care for newborn screening (NBS) is acylcarnitine metabolites quantitation by tandem mass spectrometry (MS/MS) from dried blood spots. Follow up sequencing often results in identification of one or more variants of uncertain significance (VUS). Isovaleric acidemia (IVA) is an autosomal recessive inborn error of metabolism caused by deficiency of isovaleryl-CoA dehydrogenase (IVDH) in the Leu catabolism pathway. Many IVD mutations are characterized as VUS complicating IVA clinical diagnoses and treatment. We present a testing platform approach to confirm the functional implication of VUS identified in newborns with IVA applicable to multiple inborn errors of metabolism identified by NBS. METHODS An IVD null HEK293T cell culture model was generated by using a dual sgRNA CRISPR/Cas9 genome-editing strategy targeting IVD exons 2-3. Clonal cell lines were confirmed by a combination of genomic breakpoint sequencing and droplet digital PCR. The IVD null model had no IVDH antigen signal and 96% reduction in IVDH enzyme activity. The IVD null model was transfected with vectors containing control or variant IVD and functional assays were performed to determine variant pathogenicity. RESULTS c.149G > C (p.Arg50Pro; precursor numbering), c.986T > C (p.Met329Thr), and c.1010G > A (p.Arg337Gln), c.1179del394 f. mutant proteins had reduced IVDH protein and activity. c.932C > T (p.Ala311Val), c.707C > T (p.Thr236Ile), and c.1232G > A (p.Arg411Gln) had stable IVDH protein, but no enzyme activity. c.521T > G (p.Val174Gly) had normal IVDH protein and activity. IVD variant transfection results confirmed results from IVA fibroblasts containing the same variants. CONCLUSIONS We have developed an IVD null HEK293T cell line to rapidly allow determination of VUS pathogenicity following identification of novel alleles by clinical sequencing following positive NBS results for suspected IVA. We suggest similar models can be generated via genome-editing for high throughput assessment of VUS function for a multitude of inborn errors of metabolism and can ideally supplement NBS programs.
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Affiliation(s)
- Olivia M D'Annibale
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA
| | - Erik A Koppes
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Ahmad N Alodaib
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Clinical Genomics, Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Catherine Kochersperger
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Anuradha Karunanidhi
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Al-Walid Mohsen
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA
| | - Jerry Vockley
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA.
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14
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Park KH, Gooz M, Ye ZW, Zhang J, Beeson GC, Rockey DC, Kim SH. Flavin Adenine Dinucleotide Depletion Caused by electron transfer flavoprotein subunit alpha Haploinsufficiency Leads to Hepatic Steatosis and Injury in Zebrafish. Hepatol Commun 2021; 5:976-991. [PMID: 34141984 PMCID: PMC8183174 DOI: 10.1002/hep4.1691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/24/2020] [Accepted: 01/18/2021] [Indexed: 12/03/2022] Open
Abstract
The electron transfer flavoprotein (ETF) complex, made up of the ETF alpha subunit (ETFA), ETF beta subunit (ETFB), and ETF dehydrogenase (ETFDH), regulates fatty acid β-oxidation activity while scavenging leaked electrons through flavin adenine dinucleotide (FAD)/reduced form FAD (FADH2) redox reactions in mitochondria. Here, we hypothesized that ETF dysfunction-mediated FAD deficiency may result in increased mitochondrial oxidative stress and steatosis and subsequent liver injury. We report that etfa haploinsufficiency caused hyperlipidemia, hypercholesterolemia, and hepatic steatosis and injury in adult zebrafish. Further, etfa+/ - mutant livers had reduced levels of FAD and glutathione and an increase in reactive oxygen species. Because FAD depletion might be critical in the pathogenesis of the liver lesion identified in etfa+/ - mutants, we used riboflavin to elevate FAD levels in the liver and found that riboflavin supplementation significantly suppressed hepatic steatosis and injury in etfa+/ - mutants through suppression of oxidative stress and de novo lipogenesis in the liver. Additionally, we found that adenosine triphosphate-linked mitochondrial oxygen consumption and mitochondrial membrane potential were reduced in etfa+/ - primary hepatocytes and that riboflavin supplementation corrected these defects. Conclusion: FAD depletion caused by etfa haploinsufficiency plays a key role in hepatic steatosis and oxidative stress-mediated hepatic injury in adult zebrafish. This raises the possibility that people with ETFA haploinsufficiency have a high risk for developing liver disease.
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Affiliation(s)
- Ki-Hoon Park
- Department of MedicineMedical University of South CarolinaCharlestonSCUSA
| | - Monika Gooz
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSCUSA
| | - Zhi-Wei Ye
- Department of Cell and Molecular Pharmacology and Experimental TherapeuticsMedical University of South CarolinaCharlestonSCUSA
| | - Jie Zhang
- Department of Cell and Molecular Pharmacology and Experimental TherapeuticsMedical University of South CarolinaCharlestonSCUSA
| | - Gyda C Beeson
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSCUSA
| | - Don C Rockey
- Digestive Disease Research CenterMedical University of South CarolinaCharlestonSCUSA
| | - Seok-Hyung Kim
- Department of MedicineMedical University of South CarolinaCharlestonSCUSA
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15
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Schühle K, Saft M, Vögeli B, Erb TJ, Heider J. Benzylmalonyl-CoA dehydrogenase, an enzyme involved in bacterial auxin degradation. Arch Microbiol 2021; 203:4149-4159. [PMID: 34059946 PMCID: PMC8360864 DOI: 10.1007/s00203-021-02406-3] [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: 03/24/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 11/28/2022]
Abstract
A novel acyl-CoA dehydrogenase involved in degradation of the auxin indoleacetate by Aromatoleum aromaticum was identified as a decarboxylating benzylmalonyl-CoA dehydrogenase (IaaF). It is encoded within the iaa operon coding for enzymes of indoleacetate catabolism. Using enzymatically produced benzylmalonyl-CoA, the reaction was characterized as simultaneous oxidation and decarboxylation of benzylmalonyl-CoA to cinnamoyl-CoA and CO2. Oxygen served as electron acceptor and was reduced to H2O2, whereas electron transfer flavoprotein or artificial dyes serving as electron acceptors for other acyl-CoA dehydrogenases were not used. The enzyme is homotetrameric, contains an FAD cofactor and is enantiospecific in benzylmalonyl-CoA turnover. It shows high catalytic efficiency and strong substrate inhibition with benzylmalonyl-CoA, but otherwise accepts only a few medium-chain alkylmalonyl-CoA compounds as alternative substrates with low activities. Its reactivity of oxidizing 2-carboxyacyl-CoA with simultaneous decarboxylation is unprecedented and indicates a modified reaction mechanism for acyl-CoA dehydrogenases, where elimination of the 2-carboxy group replaces proton abstraction from C2.
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Affiliation(s)
- Karola Schühle
- Laboratory for Microbial Biochemistry, Philipps University of Marburg, 35043, Marburg, Germany
| | - Martin Saft
- Laboratory for Microbial Biochemistry, Philipps University of Marburg, 35043, Marburg, Germany
| | - Bastian Vögeli
- Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Tobias J Erb
- Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.,LOEWE-Center for Synthetic Microbiology, Marburg, Germany
| | - Johann Heider
- Laboratory for Microbial Biochemistry, Philipps University of Marburg, 35043, Marburg, Germany. .,LOEWE-Center for Synthetic Microbiology, Marburg, Germany.
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16
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Cryoelectron microscopy structure and mechanism of the membrane-associated electron-bifurcating flavoprotein Fix/EtfABCX. Proc Natl Acad Sci U S A 2021; 118:2016978118. [PMID: 33372143 DOI: 10.1073/pnas.2016978118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The electron-transferring flavoprotein-menaquinone oxidoreductase ABCX (EtfABCX), also known as FixABCX for its role in nitrogen-fixing organisms, is a member of a family of electron-transferring flavoproteins that catalyze electron bifurcation. EtfABCX enables endergonic reduction of ferredoxin (E°' ∼-450 mV) using NADH (E°' -320 mV) as the electron donor by coupling this reaction to the exergonic reduction of menaquinone (E°' -80 mV). Here we report the 2.9 Å structure of EtfABCX, a membrane-associated flavin-based electron bifurcation (FBEB) complex, from a thermophilic bacterium. EtfABCX forms a superdimer with two membrane-associated EtfCs at the dimer interface that contain two bound menaquinones. The structure reveals that, in contrast to previous predictions, the low-potential electrons bifurcated from EtfAB are most likely directly transferred to ferredoxin, while high-potential electrons reduce the quinone via two [4Fe-4S] clusters in EtfX. Surprisingly, EtfX shares remarkable structural similarity with mammalian [4Fe-4S] cluster-containing ETF ubiquinone oxidoreductase (ETF-QO), suggesting an unexpected evolutionary link between bifurcating and nonbifurcating systems. Based on this structure and spectroscopic studies of a closely related EtfABCX, we propose a detailed mechanism of the catalytic cycle and the accompanying structural changes in this membrane-associated FBEB system.
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17
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Vigil W, Niks D, Franz-Badur S, Chowdhury N, Buckel W, Hille R. Spectral deconvolution of redox species in the crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase from Megasphaera elsdenii. A flavin-dependent bifurcating enzyme. Arch Biochem Biophys 2021; 701:108793. [PMID: 33587905 PMCID: PMC8040930 DOI: 10.1016/j.abb.2021.108793] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 11/30/2022]
Abstract
We have undertaken a spectral deconvolution of the three FADs of EtfAB/bcd to the spectral changes seen in the course of reduction, including the spectrally distinct anionic and neutral semiquinone states of electron-transferring and bcd flavins. We also demonstrate that, unlike similar systems, no charge-transfer complex is observed on titration of the reduced M. elsdenii EtfAB with NAD+. Finally, and significantly, we find that removal of the et FAD from EtfAB results in an uncrossing of the half-potentials of the bifurcating FAD that remains in the protein, as reflected in the accumulation of substantial FAD•− in the course of reductive titrations of the depleted EtfAB with sodium dithionite.
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Affiliation(s)
- Wayne Vigil
- Department of Biochemistry, University of California, Riverside, Riverside, CA, 92521, USA
| | - Dimitri Niks
- Department of Biochemistry, University of California, Riverside, Riverside, CA, 92521, USA
| | - Sophie Franz-Badur
- Department of Biochemistry, University of California, Riverside, Riverside, CA, 92521, USA
| | | | - Wolfgang Buckel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Fachbereich Biologie and Synmikro, Philipps-Universität, Marburg, Germany
| | - Russ Hille
- Department of Biochemistry, University of California, Riverside, Riverside, CA, 92521, USA.
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18
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Henriques BJ, Katrine Jentoft Olsen R, Gomes CM, Bross P. Electron transfer flavoprotein and its role in mitochondrial energy metabolism in health and disease. Gene 2021; 776:145407. [PMID: 33450351 DOI: 10.1016/j.gene.2021.145407] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/08/2020] [Accepted: 12/16/2020] [Indexed: 12/15/2022]
Abstract
Electron transfer flavoprotein (ETF) is an enzyme with orthologs from bacteria to humans. Human ETF is nuclear encoded by two separate genes, ETFA and ETFB, respectively. After translation, the two subunits are imported to the mitochondrial matrix space and assemble into a heterodimer containing one FAD and one AMP as cofactors. ETF functions as a hub taking up electrons from at least 14 flavoenzymes, feeding them into the respiratory chain. This represents a major source of reducing power for the electron transport chain from fatty acid oxidation and amino acid degradation. Transfer of electrons from the donor enzymes to ETF occurs by direct transfer between the enzyme bound flavins, a process that is tightly regulated by the polypeptide chain and by protein:protein interactions. ETF, in turn relays electrons to the iron sulfur cluster of the inner membrane protein ETF:QO, from where they travel via the FAD in ETF:QO to ubiquinone, entering the respiratory chain at the level of complex III. ETF recognizes its dehydrogenase partners via a recognition loop that anchors the protein on its partner followed by dynamic movements of the ETF flavin domain that bring redox cofactors in close proximity, thus promoting electron transfer. Genetic mutations in the ETFA or ETFB genes cause the Mendelian disorder multiple acyl-CoA dehydrogenase deficiency (MADD; OMIM #231680). We here review the knowledge on human ETF and investigations of the effects of disease-associated missense mutations in this protein that have promoted the understanding of the essential role that ETF plays in cellular metabolism and human disease.
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Affiliation(s)
- Bárbara J Henriques
- Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
| | - Rikke Katrine Jentoft Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark.
| | - Cláudio M Gomes
- Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
| | - Peter Bross
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark.
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19
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Wang Y, Ehsan M, Wang S, Tian X, Yan R, Song X, Xu L, Li X. Modulatory functions of recombinant electron transfer flavoprotein α subunit protein from Haemonchus contortus on goat immune cells in vitro. Vet Parasitol 2020; 288:109300. [PMID: 33152677 DOI: 10.1016/j.vetpar.2020.109300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 01/13/2023]
Abstract
Suppression and modulation of the host immune response to parasitic nematodes have been extensively studied. In the present study, we cloned and produced recombinant electron transfer flavoprotein α subunit (ETFα) protein from Haemonchus contortus (rHCETFα), a parasitic nematode of small ruminants, and studied the effect of this protein on modulating the immune response of goat peripheral blood mononuclear cells (PBMCs) and monocytes. Immunohistochemical tests verified that the HCETFα protein was localized mainly in the intestinal wall and on the body surface of worms. Immunoblot analysis revealed that rHCETFα was recognized by the serum of goats artificially infected with H. contortus. Immunofluorescence analysis indicated that rHCETFα bound to the surface of PBMCs. rHCETFα was co-incubated with goat PBMCs to observe the immunomodulatory effects exerted by HCETFα on proliferation, apoptosis, cytokine secretion and nitric oxide (NO) production. The results showed that rHCETFα suppressed the proliferation of goat PBMCs stimulated by concanavalin A and induced apoptosis in goat PBMCs. After rHCETFα exposure, IL-2, IL-4, IL-17A and TNF-α expression was markedly reduced, whereas secretion of TGF-β1 was significantly elevated, in goat PBMCs. Moreover, rHCETFα up-regulated NO production in a dose-dependent manner. FITC-dextran internalization assays showed that rHCETFα inhibited phagocytosis of goat monocytes. These results elucidate the interaction between parasites and hosts at the molecular level, suggest a possible immunomodulatory target and contribute to the search for innovative proteins that may be candidate targets for drugs and vaccines.
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Affiliation(s)
- Yujian Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China; School of Life Science, Huizhou University, Huizhou 516007, PR China.
| | - Muhammad Ehsan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Shuai Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Xiaowei Tian
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - RuoFeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - XiaoKai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - LiXin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - XiangRui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
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20
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Lepore R, Kryshtafovych A, Alahuhta M, Veraszto HA, Bomble YJ, Bufton JC, Bullock AN, Caba C, Cao H, Davies OR, Desfosses A, Dunne M, Fidelis K, Goulding CW, Gurusaran M, Gutsche I, Harding CJ, Hartmann MD, Hayes CS, Joachimiak A, Leiman PG, Loppnau P, Lovering AL, Lunin VV, Michalska K, Mir-Sanchis I, Mitra AK, Moult J, Phillips GN, Pinkas DM, Rice PA, Tong Y, Topf M, Walton JD, Schwede T. Target highlights in CASP13: Experimental target structures through the eyes of their authors. Proteins 2019; 87:1037-1057. [PMID: 31442339 PMCID: PMC6851490 DOI: 10.1002/prot.25805] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/09/2019] [Accepted: 08/19/2019] [Indexed: 01/10/2023]
Abstract
The functional and biological significance of selected CASP13 targets are described by the authors of the structures. The structural biologists discuss the most interesting structural features of the target proteins and assess whether these features were correctly reproduced in the predictions submitted to the CASP13 experiment.
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Affiliation(s)
- Rosalba Lepore
- BSC-CNS Barcelona Supercomputing Center, Barcelona, Spain
| | | | - Markus Alahuhta
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Harshul A Veraszto
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Yannick J Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Joshua C Bufton
- Nuffield Department of Medicine; Structural Genomics Consortium, University of Oxford, Oxford, UK.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Alex N Bullock
- Nuffield Department of Medicine; Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Cody Caba
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada
| | - Hongnan Cao
- Department of BioSciences, Rice University, Houston, Texas.,Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, Wisconsin
| | - Owen R Davies
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Ambroise Desfosses
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Matthew Dunne
- Institute of Food, Nutrition and Health, Zurich, Switzerland
| | | | - Celia W Goulding
- Department of Molecular Biology and Biochemistry; Pharmaceutical Sciences, University of California Irvine, Irvine, California
| | - Manickam Gurusaran
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | | | - Marcus D Hartmann
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, Biomolecular Science and Engineering Program, University of California, Santa Barbara, California
| | - Andrzej Joachimiak
- Structural Biology Center, Biosciences Division, Midwest Center for Structural Genomics, Argonne.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois
| | - Petr G Leiman
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas
| | - Peter Loppnau
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | | | - Vladimir V Lunin
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado
| | - Karolina Michalska
- Structural Biology Center, Biosciences Division, Midwest Center for Structural Genomics, Argonne
| | - Ignacio Mir-Sanchis
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois
| | - A K Mitra
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - John Moult
- Institute for Bioscience and Biotechnology Research, Department of Cell Biology and Molecular genetics, University of Maryland, Rockville, Maryland, USA
| | - George N Phillips
- Department of BioSciences, Rice University, Houston, Texas.,Great Lakes Bioenergy Research Center, University of Wisconsin, Madison, Wisconsin
| | - Daniel M Pinkas
- Nuffield Department of Medicine; Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois
| | - Yufeng Tong
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada.,Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Maya Topf
- Institute of Structural and Molecular Biology, Birkbeck, University College London, London, UK
| | - Jonathan D Walton
- Great Lakes Bioenergy Research Center and Department of Plant Biology, Michigan State University, East Lansing, Michigan
| | - Torsten Schwede
- Biozentrum University of Basel, Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, Biozentrum University of Basel, Basel, Switzerland
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21
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McGlaughon JL, Pasquali M, Wallace K, Ross J, Senol-Cosar O, Shen W, Weaver MA, Feigenbaum A, Lyon E, Enns GM, Mao R, Baudet HG. Assessing the strength of evidence for genes implicated in fatty acid oxidation disorders using the ClinGen clinical validity framework. Mol Genet Metab 2019; 128:122-128. [PMID: 31399326 DOI: 10.1016/j.ymgme.2019.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 12/30/2022]
Abstract
Newborn screening is an incredibly useful tool for the early identification of many metabolic disorders, including fatty acid oxidation (FAO) disorders. In many cases, molecular tests are necessary to reach a final diagnosis, highlighting the need for a thorough evaluation of genes implicated in FAO disorders. Using the ClinGen (Clinical Genome Resource) clinical validity framework, thirty genes were analyzed for the strength of evidence supporting their association with FAO disorders. Evidence was gathered from the literature by biocurators and presented to disease experts for review in order to assign a clinical validity classification of Definitive, Strong, Moderate, Limited, Disputed, Refuted, or No Reported Evidence. Of the gene-disease relationships evaluated, 22/30 were classified as Definitive, three as Moderate, one as Limited, three as No Reported Evidence and one as Disputed. Gene-disease relationships with a Limited, Disputed, and No Reported Evidence were found on two, six, and up to four panels out of 30 FAO disorder-specific panels, respectively, in the National Institute of Health Genetic Testing Registry, while over 70% of the genes on panels are definitively associated with an FAO disorder. These results highlight the need to systematically assess the clinical relevance of genes implicated in fatty acid oxidation disorders in order to improve the interpretation of genetic testing results and diagnosis of patients with these disorders.
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Affiliation(s)
- Jennifer L McGlaughon
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, NC, USA
| | - Marzia Pasquali
- University of Utah and ARUP Laboratories, Salt Lake City, UT, USA
| | - Kathleen Wallace
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, NC, USA
| | - Justyne Ross
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, NC, USA
| | - Ozlem Senol-Cosar
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, MA, USA; Department of Pathology, Harvard Medical School/Brigham and Women's Hospital, Boston, MA, USA
| | - Wei Shen
- University of Utah and ARUP Laboratories, Salt Lake City, UT, USA
| | - Meredith A Weaver
- American College of Medical Genetics and Genomics, Bethesda, MD, USA
| | - Annette Feigenbaum
- Department of Pediatrics, University of California San Diego and Rady Children's Hospital, San Diego, CA, USA
| | - Elaine Lyon
- University of Utah and ARUP Laboratories, Salt Lake City, UT, USA
| | - Gregory M Enns
- Department of Pediatrics, Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | - Rong Mao
- University of Utah and ARUP Laboratories, Salt Lake City, UT, USA
| | - Heather G Baudet
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, NC, USA.
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22
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Mitochondrial β-oxidation of saturated fatty acids in humans. Mitochondrion 2018; 46:73-90. [PMID: 29551309 DOI: 10.1016/j.mito.2018.02.009] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/04/2017] [Accepted: 02/27/2018] [Indexed: 12/30/2022]
Abstract
Mitochondrial β-oxidation of fatty acids generates acetyl-coA, NADH and FADH2. Acyl-coA synthetases catalyze the binding of fatty acids to coenzyme A to form fatty acyl-coA thioesters, the first step in the intracellular metabolism of fatty acids. l-carnitine system facilitates the transport of fatty acyl-coA esters across the mitochondrial membrane. Carnitine palmitoyltransferase-1 transfers acyl groups from coenzyme A to l-carnitine, forming acyl-carnitine esters at the outer mitochondrial membrane. Carnitine acyl-carnitine translocase exchanges acyl-carnitine esters that enter the mitochondria, by free l-carnitine. Carnitine palmitoyltransferase-2 converts acyl-carnitine esters back to acyl-coA esters at the inner mitochondrial membrane. The β-oxidation pathway of fatty acyl-coA esters includes four reactions. Fatty acyl-coA dehydrogenases catalyze the introduction of a double bond at the C2 position, producing 2-enoyl-coA esters and reducing equivalents that are transferred to the respiratory chain via electron transferring flavoprotein. Enoyl-coA hydratase catalyzes the hydration of the double bond to generate a 3-l-hydroxyacyl-coA derivative. 3-l-hydroxyacyl-coA dehydrogenase catalyzes the formation of a 3-ketoacyl-coA intermediate. Finally, 3-ketoacyl-coA thiolase catalyzes the cleavage of the chain, generating acetyl-coA and a fatty acyl-coA ester two carbons shorter. Mitochondrial trifunctional protein catalyzes the three last steps in the β-oxidation of long-chain and medium-chain fatty acyl-coA esters while individual enzymes catalyze the β-oxidation of short-chain fatty acyl-coA esters. Clinical phenotype of fatty acid oxidation disorders usually includes hypoketotic hypoglycemia triggered by fasting or infections, skeletal muscle weakness, cardiomyopathy, hepatopathy, and neurological manifestations. Accumulation of non-oxidized fatty acids promotes their conjugation with glycine and l-carnitine and alternate ways of oxidation, such as ω-oxidation.
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Augustin P, Toplak M, Fuchs K, Gerstmann EC, Prassl R, Winkler A, Macheroux P. Oxidation of the FAD cofactor to the 8-formyl-derivative in human electron-transferring flavoprotein. J Biol Chem 2018; 293:2829-2840. [PMID: 29301933 PMCID: PMC5827430 DOI: 10.1074/jbc.ra117.000846] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/14/2017] [Indexed: 11/06/2022] Open
Abstract
The heterodimeric human (h) electron-transferring flavoprotein (ETF) transfers electrons from at least 13 different flavin dehydrogenases to the mitochondrial respiratory chain through a non-covalently bound FAD cofactor. Here, we describe the discovery of an irreversible and pH-dependent oxidation of the 8α-methyl group to 8-formyl-FAD (8f-FAD), which represents a unique chemical modification of a flavin cofactor in the human flavoproteome. Furthermore, a set of hETF variants revealed that several conserved amino acid residues in the FAD-binding pocket of electron-transferring flavoproteins are required for the conversion to the formyl group. Two of the variants generated in our study, namely αR249C and αT266M, cause glutaric aciduria type II, a severe inherited disease. Both of the variants showed impaired formation of 8f-FAD shedding new light on the potential molecular cause of disease development. Interestingly, the conversion of FAD to 8f-FAD yields a very stable flavin semiquinone that exhibited slightly lower rates of electron transfer in an artificial assay system than hETF containing FAD. In contrast, the formation of 8f-FAD enhanced the affinity to human dimethylglycine dehydrogenase 5-fold, indicating that formation of 8f-FAD modulates the interaction of hETF with client enzymes in the mitochondrial matrix. Thus, we hypothesize that the FAD cofactor bound to hETF is subject to oxidation in the alkaline (pH 8) environment of the mitochondrial matrix, which may modulate electron transport between client dehydrogenases and the respiratory chain. This discovery challenges the current concepts of electron transfer processes in mitochondria.
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Affiliation(s)
- Peter Augustin
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II
| | - Marina Toplak
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II
| | - Katharina Fuchs
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II
| | | | - Ruth Prassl
- Institute of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/IV, 8010 Graz, Austria
| | - Andreas Winkler
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II.
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24
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Molecular basis of the flavin-based electron-bifurcating caffeyl-CoA reductase reaction. FEBS Lett 2018; 592:332-342. [DOI: 10.1002/1873-3468.12971] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/04/2018] [Accepted: 01/04/2018] [Indexed: 11/07/2022]
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25
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Shimazu T, Furuse T, Balan S, Yamada I, Okuno S, Iwanari H, Suzuki T, Hamakubo T, Dohmae N, Yoshikawa T, Wakana S, Shinkai Y. Role of METTL20 in regulating β-oxidation and heat production in mice under fasting or ketogenic conditions. Sci Rep 2018; 8:1179. [PMID: 29352221 PMCID: PMC5775328 DOI: 10.1038/s41598-018-19615-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/04/2018] [Indexed: 12/18/2022] Open
Abstract
METTL20 is a seven-β-strand methyltransferase that is localised to the mitochondria and tri-methylates the electron transfer flavoprotein (ETF) β subunit (ETFB) at lysines 200 and 203. It has been shown that METTL20 decreases the ability of ETF to extract electrons from medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) and glutaryl-CoA dehydrogenase in vitro. METTL20-mediated methylation of ETFB influences the oxygen consumption rate in permeabilised mitochondria, suggesting that METTL20-mediated ETFB methylation may also play a regulatory role in mitochondrial metabolism. In this study, we generated Mettl20 knockout (KO) mice to uncover the in vivo functions of METTL20. The KO mice were viable, and a loss of ETFB methylation was confirmed. In vitro enzymatic assays revealed that mitochondrial ETF activity was higher in the KO mice than in wild-type mice, suggesting that the KO mice had higher β-oxidation capacity. Calorimetric analysis showed that the KO mice fed a ketogenic diet had higher oxygen consumption and heat production. A subsequent cold tolerance test conducted after 24 h of fasting indicated that the KO mice had a better ability to maintain their body temperature in cold environments. Thus, METTL20 regulates ETF activity and heat production through lysine methylation when β-oxidation is highly activated.
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Affiliation(s)
- Tadahiro Shimazu
- Cellular Memory Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Tamio Furuse
- Japan Mouse Clinic, RIKEN BRC, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | - Shabeesh Balan
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
| | - Ikuko Yamada
- Japan Mouse Clinic, RIKEN BRC, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | - Shuzo Okuno
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8507, Japan
| | - Hiroko Iwanari
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198, Japan
| | - Takao Hamakubo
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198, Japan
| | - Takeo Yoshikawa
- Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
| | - Shigeharu Wakana
- Japan Mouse Clinic, RIKEN BRC, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
| | - Yoichi Shinkai
- Cellular Memory Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
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26
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Demmer JK, Pal Chowdhury N, Selmer T, Ermler U, Buckel W. The semiquinone swing in the bifurcating electron transferring flavoprotein/butyryl-CoA dehydrogenase complex from Clostridium difficile. Nat Commun 2017; 8:1577. [PMID: 29146947 PMCID: PMC5691135 DOI: 10.1038/s41467-017-01746-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 10/13/2017] [Indexed: 11/29/2022] Open
Abstract
The electron transferring flavoprotein/butyryl-CoA dehydrogenase (EtfAB/Bcd) catalyzes the reduction of one crotonyl-CoA and two ferredoxins by two NADH within a flavin-based electron-bifurcating process. Here we report on the X-ray structure of the Clostridium difficile (EtfAB/Bcd)4 complex in the dehydrogenase-conducting D-state, α-FAD (bound to domain II of EtfA) and δ-FAD (bound to Bcd) being 8 Å apart. Superimposing Acidaminococcus fermentans EtfAB onto C. difficile EtfAB/Bcd reveals a rotation of domain II of nearly 80°. Further rotation by 10° brings EtfAB into the bifurcating B-state, α-FAD and β-FAD (bound to EtfB) being 14 Å apart. This dual binding mode of domain II, substantiated by mutational studies, resembles findings in non-bifurcating EtfAB/acyl-CoA dehydrogenase complexes. In our proposed mechanism, NADH reduces β-FAD, which bifurcates. One electron goes to ferredoxin and one to α-FAD, which swings over to reduce δ-FAD to the semiquinone. Repetition affords a second reduced ferredoxin and δ-FADH−, which reduces crotonyl-CoA. The electron-transferring flavoprotein / butyryl-CoA dehydrogenase (EtfAB/Bcd) complex catalyzes the reduction of crotonyl-CoA and ferredoxins by NADH in anaerobic microbes. Here, the authors present the crystal structure of Clostridium difficile EtfAB/Bcd and discuss the bifurcation mechanism for electron flow.
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Affiliation(s)
- Julius K Demmer
- Max-Planck-Institut für Biophysik, Max-von-Laue-Str. 3, 60438, Frankfurt am Main, Germany
| | - Nilanjan Pal Chowdhury
- Laboratorium für Mikrobiologie, Fachbereich Biologie and SYNMIKRO, Philipps-Universität, 35032, Marburg, Germany.,Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany
| | - Thorsten Selmer
- Fachbereich Chemie und Biotechnologie, FH Aachen, Heinrich-Mußmann-Str. 1, 52428, Jülich, Germany
| | - Ulrich Ermler
- Max-Planck-Institut für Biophysik, Max-von-Laue-Str. 3, 60438, Frankfurt am Main, Germany.
| | - Wolfgang Buckel
- Laboratorium für Mikrobiologie, Fachbereich Biologie and SYNMIKRO, Philipps-Universität, 35032, Marburg, Germany. .,Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany.
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27
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Schmiesing J, Lohmöller B, Schweizer M, Tidow H, Gersting SW, Muntau AC, Braulke T, Mühlhausen C. Disease-causing mutations affecting surface residues of mitochondrial glutaryl-CoA dehydrogenase impair stability, heteromeric complex formation and mitochondria architecture. Hum Mol Genet 2017; 26:538-551. [PMID: 28062662 DOI: 10.1093/hmg/ddw411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 11/28/2016] [Indexed: 01/22/2023] Open
Abstract
The neurometabolic disorder glutaric aciduria type 1 (GA1) is caused by mutations in the GCDH gene encoding the mitochondrial matrix protein glutaryl-CoA dehydrogenase (GCDH), which forms homo- and heteromeric complexes. Twenty percent of all pathogenic mutations affect single amino acid residues on the surface of GCDH resulting in a severe clinical phenotype. We report here on heterologous expression studies of 18 missense mutations identified in GA1 patients affecting surface amino acids. Western blot and pulse chase experiments revealed that the stability of half of the GCDH mutants was significantly reduced. In silico analyses showed that none of the mutations impaired the 3D structure of GCDH. Immunofluorescence co-localisation studies in HeLa cells demonstrated that all GCDH mutants were correctly translocated into mitochondria. Surprisingly, the expression of p.Arg88Cys GCDH as well as further substitutions by alanine, lysine, or methionine but not histidine or leucine resulted in the disruption of mitochondrial architecture forming longitudinal structures composed of stacks of cristae and partial loss of the outer mitochondrial membrane. The expression of mitochondrial fusion or fission proteins was not affected in these cells. Bioluminescence resonance energy transfer analyses revealed that all GCDH mutants exhibit an increased binding affinity to electron transfer flavoprotein beta, whereas only p.Tyr155His GCDH showed a reduced interaction with dihydrolipoamide succinyl transferase. Our data underscore the impact of GCDH protein interactions mediated by amino acid residues on the surface of GCDH required for proper enzymatic activity.
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Affiliation(s)
- Jessica Schmiesing
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Benjamin Lohmöller
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michaela Schweizer
- Center of Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Henning Tidow
- The Hamburg Centre for Ultrafast Imaging & Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Søren W Gersting
- Department of Molecular Pediatrics, Dr. von Hauner Childrens Hospital, Ludwig-Maximilians-University, Munich, Germany and
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Braulke
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Chris Mühlhausen
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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28
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Coupling between d-3-phosphoglycerate dehydrogenase and d-2-hydroxyglutarate dehydrogenase drives bacterial l-serine synthesis. Proc Natl Acad Sci U S A 2017; 114:E7574-E7582. [PMID: 28827360 DOI: 10.1073/pnas.1619034114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
l-Serine biosynthesis, a crucial metabolic process in most domains of life, is initiated by d-3-phosphoglycerate (d-3-PG) dehydrogenation, a thermodynamically unfavorable reaction catalyzed by d-3-PG dehydrogenase (SerA). d-2-Hydroxyglutarate (d-2-HG) is traditionally viewed as an abnormal metabolite associated with cancer and neurometabolic disorders. Here, we reveal that bacterial anabolism and catabolism of d-2-HG are involved in l-serine biosynthesis in Pseudomonas stutzeri A1501 and Pseudomonas aeruginosa PAO1. SerA catalyzes the stereospecific reduction of 2-ketoglutarate (2-KG) to d-2-HG, responsible for the major production of d-2-HG in vivo. SerA combines the energetically favorable reaction of d-2-HG production to overcome the thermodynamic barrier of d-3-PG dehydrogenation. We identified a bacterial d-2-HG dehydrogenase (D2HGDH), a flavin adenine dinucleotide (FAD)-dependent enzyme, that converts d-2-HG back to 2-KG. Electron transfer flavoprotein (ETF) and ETF-ubiquinone oxidoreductase (ETFQO) are also essential in d-2-HG metabolism through their capacity to transfer electrons from D2HGDH. Furthermore, while the mutant with D2HGDH deletion displayed decreased growth, the defect was rescued by adding l-serine, suggesting that the D2HGDH is functionally tied to l-serine synthesis. Substantial flux flows through d-2-HG, being produced by SerA and removed by D2HGDH, ETF, and ETFQO, maintaining d-2-HG homeostasis. Overall, our results uncover that d-2-HG-mediated coupling between SerA and D2HGDH drives bacterial l-serine synthesis.
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29
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Rhein VF, Carroll J, Ding S, Fearnley IM, Walker JE. Human METTL12 is a mitochondrial methyltransferase that modifies citrate synthase. FEBS Lett 2017; 591:1641-1652. [PMID: 28391595 PMCID: PMC5518231 DOI: 10.1002/1873-3468.12649] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 01/13/2023]
Abstract
The protein methylome in mammalian mitochondria has been little studied until recently. Here, we describe that lysine-368 of human citrate synthase is methylated and that the modifying enzyme, localized in the mitochondrial matrix, is methyltransferase-like protein 12 (METTL12), a member of the family of 7β-strand methyltransferases. Lysine-368 is near the active site of citrate synthase, but removal of methylation has no effect on its activity. In mitochondria, it is possible that some or all of the enzymes of the citric acid cycle, including citrate synthase, are organized in metabolons to facilitate the channelling of substrates between participating enzymes. Thus, possible roles for the methylation of Lys-368 are in controlling substrate channelling itself, or in influencing protein-protein interactions in the metabolon.
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Affiliation(s)
- Virginie F Rhein
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - Joe Carroll
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - Shujing Ding
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - Ian M Fearnley
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - John E Walker
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
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30
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Bonito CA, Leandro P, Ventura FV, Guedes RC. Insights into Medium-chain Acyl-CoA Dehydrogenase Structure by Molecular Dynamics Simulations. Chem Biol Drug Des 2016; 88:281-92. [PMID: 26992026 DOI: 10.1111/cbdd.12755] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/27/2016] [Accepted: 02/29/2016] [Indexed: 11/29/2022]
Abstract
The medium-chain acyl-CoA dehydrogenase (MCAD) is a mitochondrial enzyme that catalyzes the first step of mitochondrial fatty acid β-oxidation (mFAO) pathway. Its deficiency is the most common genetic disorder of mFAO. Many of the MCAD disease-causing variants, including the most common p.K304E variant, show loss of function due to protein misfolding. Herein, we used molecular dynamics simulations to provide insights into the structural stability and dynamic behavior of MCAD wild-type (MCADwt) and validate a structure that would allow reliable new studies on its variants. Our results revealed that in both proteins the flavin adenine dinucleotide (FAD) has an important structural role on the tetramer stability and also in maintaining the volume of the enzyme catalytic pockets. We confirmed that the presence of substrate changes the dynamics of the catalytic pockets and increases FAD affinity. A comparison between the porcine MCADwt (pMCADwt) and human MCADwt (hMCADwt) structures revealed that both proteins are essentially similar and that the reversion of the double mutant E376G/T255E of hMCAD enzyme does not affect the structure of the protein neither its behavior in simulation. Our validated hMCADwt structure is crucial for complementing and accelerating the experimental studies aiming for the discovery and development of potential stabilizers of MCAD variants as candidates for the treatment of MCAD deficiency (MCADD).
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Affiliation(s)
- Cátia A Bonito
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, 1649-003, Portugal.,Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal.,Medicinal Chemistry, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal.,Department of Pharmaceutical Chemistry and Therapeutics, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, 1649-003, Portugal
| | - Paula Leandro
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, 1649-003, Portugal.,Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
| | - Fátima V Ventura
- Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, 1649-003, Portugal.,Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
| | - Rita C Guedes
- Medicinal Chemistry, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal.,Department of Pharmaceutical Chemistry and Therapeutics, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, 1649-003, Portugal
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31
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Chowdhury NP, Klomann K, Seubert A, Buckel W. Reduction of Flavodoxin by Electron Bifurcation and Sodium Ion-dependent Reoxidation by NAD+ Catalyzed by Ferredoxin-NAD+ Reductase (Rnf). J Biol Chem 2016; 291:11993-2002. [PMID: 27048649 DOI: 10.1074/jbc.m116.726299] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Indexed: 12/31/2022] Open
Abstract
Electron-transferring flavoprotein (Etf) and butyryl-CoA dehydrogenase (Bcd) from Acidaminococcus fermentans catalyze the endergonic reduction of ferredoxin by NADH, which is also driven by the concomitant reduction of crotonyl-CoA by NADH, a process called electron bifurcation. Here we show that recombinant flavodoxin from A. fermentans produced in Escherichia coli can replace ferredoxin with almost equal efficiency. After complete reduction of the yellow quinone to the blue semiquinone, a second 1.4 times faster electron transfer affords the colorless hydroquinone. Mediated by a hydrogenase, protons reoxidize the fully reduced flavodoxin or ferredoxin to the semi-reduced species. In this hydrogen-generating system, both electron carriers act catalytically with apparent Km = 0.26 μm ferredoxin or 0.42 μm flavodoxin. Membrane preparations of A. fermentans contain a highly active ferredoxin/flavodoxin-NAD(+) reductase (Rnf) that catalyzes the irreversible reduction of flavodoxin by NADH to the blue semiquinone. Using flavodoxin hydroquinone or reduced ferredoxin obtained by electron bifurcation, Rnf can be measured in the forward direction, whereby one NADH is recycled, resulting in the simple equation: crotonyl-CoA + NADH + H(+) = butyryl-CoA + NAD(+) with Km = 1.4 μm ferredoxin or 2.0 μm flavodoxin. This reaction requires Na(+) (Km = 0.12 mm) or Li(+) (Km = 0.25 mm) for activity, indicating that Rnf acts as a Na(+) pump. The redox potential of the quinone/semiquinone couple of flavodoxin (Fld) is much higher than that of the semiquinone/hydroquinone couple. With free riboflavin, the opposite is the case. Based on this behavior, we refine our previous mechanism of electron bifurcation.
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Affiliation(s)
- Nilanjan Pal Chowdhury
- From the Laboratorium für Mikrobiologie, Fachbereich Biologie and Synmikro and the Max-Plank-Institut für terrestrische Mikrobiologie, 35043 Marburg, Germany
| | - Katharina Klomann
- From the Laboratorium für Mikrobiologie, Fachbereich Biologie and Synmikro and
| | - Andreas Seubert
- the Fachbereich Chemie, Philipps-Universität, 35032 Marburg, and
| | - Wolfgang Buckel
- From the Laboratorium für Mikrobiologie, Fachbereich Biologie and Synmikro and the Max-Plank-Institut für terrestrische Mikrobiologie, 35043 Marburg, Germany
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32
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Małecki J, Dahl HA, Moen A, Davydova E, Falnes PØ. The METTL20 Homologue from Agrobacterium tumefaciens Is a Dual Specificity Protein-lysine Methyltransferase That Targets Ribosomal Protein L7/L12 and the β Subunit of Electron Transfer Flavoprotein (ETFβ). J Biol Chem 2016; 291:9581-95. [PMID: 26929405 DOI: 10.1074/jbc.m115.709261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Indexed: 12/31/2022] Open
Abstract
Human METTL20 is a mitochondrial, lysine-specific methyltransferase that methylates the β-subunit of electron transfer flavoprotein (ETFβ). Interestingly, putative METTL20 orthologues are found in a subset of α-proteobacteria, including Agrobacterium tumefaciens Using an activity-based approach, we identified in bacterial extracts two substrates of recombinant METTL20 from A. tumefaciens (AtMETTL20), namely ETFβ and the ribosomal protein RpL7/L12. We show that AtMETTL20, analogous to the human enzyme, methylates ETFβ on Lys-193 and Lys-196 both in vitro and in vivo ETF plays a key role in mediating electron transfer from various dehydrogenases, and we found that its electron transferring ability was diminished by AtMETTL20-mediated methylation of ETFβ. Somewhat surprisingly, AtMETTL20 also catalyzed monomethylation of RpL7/L12 on Lys-86, a common modification also found in many bacteria that lack METTL20. Thus, we here identify AtMETTL20 as the first enzyme catalyzing RpL7/L12 methylation. In summary, here we have identified and characterized a novel bacterial lysine-specific methyltransferase with unprecedented dual substrate specificity within the seven β-strand class of lysine-specific methyltransferases, as it targets two apparently unrelated substrates, ETFβ and RpL7/L12. Moreover, the present work establishes METTL20-mediated methylation of ETFβ as the first lysine methylation event occurring in both bacteria and humans.
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Affiliation(s)
- Jędrzej Małecki
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo 0316, Norway
| | - Helge-André Dahl
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo 0316, Norway
| | - Anders Moen
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo 0316, Norway
| | - Erna Davydova
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo 0316, Norway
| | - Pål Ø Falnes
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo 0316, Norway
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33
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Leferink NGH, Hay S, Rigby SEJ, Scrutton NS. Towards the free energy landscape for catalysis in mammalian nitric oxide synthases. FEBS J 2014; 282:3016-29. [PMID: 25491181 DOI: 10.1111/febs.13171] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/05/2014] [Accepted: 12/05/2014] [Indexed: 01/30/2023]
Abstract
The general requirement for conformational sampling in biological electron transfer reactions catalysed by multi-domain redox systems has been emphasized in recent years. Crucially, we lack insight into the extent of the conformational space explored and the nature of the energy landscapes associated with these reactions. The nitric oxide synthases (NOS) produce the signalling molecule NO through a series of complex electron transfer reactions. There is accumulating evidence that protein domain dynamics and calmodulin binding are implicated in regulating electron flow from NADPH, through the FAD and FMN cofactors, to the haem oxygenase domain, where NO is generated. Simple models based on static crystal structures of the isolated reductase domain have suggested a role for large-scale motions of the FMN-binding domain in shuttling electrons from the reductase domain to the oxygenase domain. However, detailed insight into the higher-order domain architecture and dynamic structural transitions in NOS enzymes during enzyme turnover is lacking. In this review, we discuss the recent advances made towards mapping the catalytic free energy landscapes of NOS enzymes through integration of both structural techniques (e.g. cryo-electron microscopy) and biophysical techniques (e.g. pulsed-electron paramagnetic resonance). The general picture that emerges from these experiments is that NOS enzymes exist in an equilibrium of conformations, comprising a 'rugged' or 'frustrated' energy landscape, with a key regulatory role for calmodulin in driving vectorial electron transfer by altering the conformational equilibrium. A detailed understanding of these landscapes may provide new opportunities for discovery of isoform-specific inhibitors that bind at the dynamic interfaces of these multi-dimensional energy landscapes.
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Affiliation(s)
- Nicole G H Leferink
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Stephen E J Rigby
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and Faculty of Life Sciences, The University of Manchester, UK
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Małecki J, Ho AYY, Moen A, Dahl HA, Falnes PØ. Human METTL20 is a mitochondrial lysine methyltransferase that targets the β subunit of electron transfer flavoprotein (ETFβ) and modulates its activity. J Biol Chem 2014; 290:423-34. [PMID: 25416781 DOI: 10.1074/jbc.m114.614115] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Proteins are frequently modified by post-translational methylation of lysine residues, catalyzed by S-adenosylmethionine-dependent lysine methyltransferases (KMTs). Lysine methylation of histone proteins has been extensively studied, but it has recently become evident that methylation of non-histone proteins is also abundant and important. The human methyltransferase METTL20 belongs to a group of 10 established and putative human KMTs. We here found METTL20 to be associated with mitochondria and determined that recombinant METTL20 methylated a single protein in extracts from human cells. Using an methyltransferase activity-based purification scheme, we identified the β-subunit of the mitochondrially localized electron transfer flavoprotein (ETFβ) as the substrate of METTL20. Furthermore, METTL20 was found to specifically methylate two adjacent lysine residues, Lys(200) and Lys(203), in ETFβ both in vitro and in cells. Interestingly, the residues methylated by METTL20 partially overlap with the so-called "recognition loop" in ETFβ, which has been shown to mediate its interaction with various dehydrogenases. Accordingly, we found that METTL20-mediated methylation of ETFβ in vitro reduced its ability to receive electrons from the medium chain acyl-CoA dehydrogenase and the glutaryl-CoA dehydrogenase. In conclusion, the present study establishes METTL20 as the first human KMT localized to mitochondria and suggests that it may regulate cellular metabolism through modulating the interaction between its substrate ETFβ and dehydrogenases. Based on the previous naming of similar enzymes, we suggest the renaming of human METTL20 to ETFβ-KMT.
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Affiliation(s)
- Jędrzej Małecki
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
| | - Angela Y Y Ho
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
| | - Anders Moen
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
| | - Helge-André Dahl
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
| | - Pål Ø Falnes
- From the Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, 0316, Norway
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Kinetic and spectral properties of isovaleryl-CoA dehydrogenase and interaction with ligands. Biochimie 2014; 108:108-19. [PMID: 25450250 DOI: 10.1016/j.biochi.2014.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 11/10/2014] [Indexed: 11/21/2022]
Abstract
Isovaleryl-CoA dehydrogenase (IVD) catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA and the transfer of electrons to the electron transfer flavoprotein (ETF). Recombinant human IVD purifies with bound CoA-persulfide. A modified purification protocol was developed to isolate IVD without bound CoA-persulfide and to protect the protein thiols from oxidation. The CoA-persulfide-free IVD specific activity was 112.5 μmol porcine ETF min(-)(1) mg(-)(1), which was ∼20-fold higher than that of its CoA-persulfide bound form. The Km and catalytic efficiency (kcat/Km) for isovaleryl-CoA were 1.0 μM and 4.3 × 10(6) M(-1) s(-1) per monomer, respectively, and its Km for ETF was 2.0 μM. Anaerobic titration of isovaleryl-CoA into an IVD solution resulted in a stable blue complex with increased absorbance at 310 nm, decreased absorbance at 373 and 447 nm, and the appearance of the charge transfer complex band at 584 nm. The apparent dissociation constant (KDapp) determined spectrally for isovaleryl-CoA was 0.54 μM. Isovaleryl-CoA, acetoacetyl-CoA, methylenecyclopropyl-acetyl-CoA, and ETF induced CD spectral changes at the 250-500 nm region while isobutyryl-CoA did not, suggesting conformational changes occur at the flavin ring that are ligand specific. Replacement of the IVD Trp166 with a Phe did not block IVD interaction with ETF, indicating that its indole ring is not essential for electron transfer to ETF. A twelve amino acid synthetic peptide that matches the sequence of the ETF docking peptide competitively inhibited the enzyme reaction when ETF was used as the electron acceptor with a Ki of 1.5 mM.
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Koster KL, Sturm M, Herebian D, Smits SHJ, Spiekerkoetter U. Functional studies of 18 heterologously expressed medium-chain acyl-CoA dehydrogenase (MCAD) variants. J Inherit Metab Dis 2014; 37:917-28. [PMID: 24966162 DOI: 10.1007/s10545-014-9732-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 05/22/2014] [Accepted: 06/02/2014] [Indexed: 12/30/2022]
Abstract
Medium-chain acyl-coenzyme-A dehydrogenase (MCAD) catalyzes the first step of mitochondrial beta-oxidation for medium-chain acyl-CoAs. Mutations in the ACADM gene cause MCAD deficiency presenting with life-threatening symptoms during catabolism. Since fatty-acid-oxidation disorders are part of newborn screening (NBS), many novel mutations with unknown clinical relevance have been identified in asymptomatic newborns. Eighteen of these mutations were separately cloned into the human ACADM gene, heterologously overexpressed in Escherichia coli and functionally characterized by using different substrates, molecular chaperones, and measured at different temperatures. In addition, they were mapped to the three-dimensional MCAD structure, and cross-link experiments were performed. This study identified variants that only moderately affect the MCAD protein in vitro, such as Y42H, E18K, and R6H, in contrast to the remaining 15 mutants. These three mutants display residual octanoyl-CoA oxidation activities in the range of 22 % to 47 %, are as temperature sensitive as the wild type, and reach 100 % activity with molecular chaperone co-overexpression. Projection into the three-dimensional protein structure gave some indication as to possible reasons for decreased enzyme activities. Additionally, six of the eight novel mutations, functionally characterized for the first time, showed severely reduced residual activities < 5 % despite high expression levels. These studies are of relevance because they classify novel mutants in vitro on the basis of their corresponding functional effects. This basic knowledge should be taken into consideration for individual management after NBS.
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Affiliation(s)
- Kira-Lee Koster
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Moorenstr.5, 40225, Duesseldorf, Germany
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Rhein VF, Carroll J, He J, Ding S, Fearnley IM, Walker JE. Human METTL20 methylates lysine residues adjacent to the recognition loop of the electron transfer flavoprotein in mitochondria. J Biol Chem 2014; 289:24640-51. [PMID: 25023281 PMCID: PMC4148887 DOI: 10.1074/jbc.m114.580464] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In mammalian mitochondria, protein methylation is a relatively uncommon post-transcriptional modification, and the extent of the mitochondrial protein methylome, the modifying methyltransferases, and their substrates have been little studied. As shown here, the β-subunit of the electron transfer flavoprotein (ETF) is one such methylated protein. The ETF is a heterodimer of α- and β-subunits. Lysine residues 199 and 202 of mature ETFβ are almost completely trimethylated in bovine heart mitochondria, whereas ETFα is not methylated. The enzyme responsible for the modifications was identified as methyltransferase-like protein 20 (METTL20). In human 143B cells, the methylation of ETFβ is less extensive and is diminished further by suppression of METTL20. Tagged METTL20 expressed in HEK293T cells specifically associates with the ETF and promotes the trimethylation of ETFβ lysine residues 199 and 202. ETF serves as a mobile electron carrier linking dehydrogenases involved in fatty acid oxidation and one-carbon metabolism to the membrane-associated ubiquinone pool. The methylated residues in ETFβ are immediately adjacent to a protein loop that recognizes and binds to the dehydrogenases. Suppression of trimethylation of ETFβ in mouse C2C12 cells oxidizing palmitate as an energy source reduced the consumption of oxygen by the cells. These experiments suggest that the oxidation of fatty acids in mitochondria and the passage of electrons via the ETF may be controlled by modulating the protein-protein interactions between the reduced dehydrogenases and the β-subunit of the ETF by trimethylation of lysine residues. METTL20 is the first lysine methyltransferase to be found to be associated with mitochondria.
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Affiliation(s)
- Virginie F Rhein
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Joe Carroll
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Jiuya He
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Shujing Ding
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Ian M Fearnley
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - John E Walker
- From The Medical Research Council Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom
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Sobolewska-Stawiarz A, Leferink NGH, Fisher K, Heyes DJ, Hay S, Rigby SEJ, Scrutton NS. Energy landscapes and catalysis in nitric-oxide synthase. J Biol Chem 2014; 289:11725-11738. [PMID: 24610812 PMCID: PMC4002082 DOI: 10.1074/jbc.m114.548834] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nitric oxide (NO) plays diverse roles in mammalian physiology. It is involved in blood pressure regulation, neurotransmission, and immune response, and is generated through complex electron transfer reactions catalyzed by NO synthases (NOS). In neuronal NOS (nNOS), protein domain dynamics and calmodulin binding are implicated in regulating electron flow from NADPH, through the FAD and FMN cofactors, to the heme oxygenase domain, the site of NO generation. Simple models based on crystal structures of nNOS reductase have invoked a role for large scale motions of the FMN-binding domain in shuttling electrons from the FAD-binding domain to the heme oxygenase domain. However, molecular level insight of the dynamic structural transitions in NOS enzymes during enzyme catalysis is lacking. We use pulsed electron-electron double resonance spectroscopy to derive inter-domain distance relationships in multiple conformational states of nNOS. These distance relationships are correlated with enzymatic activity through variable pressure kinetic studies of electron transfer and turnover. The binding of NADPH and calmodulin are shown to influence interdomain distance relationships as well as reaction chemistry. An important effect of calmodulin binding is to suppress adventitious electron transfer from nNOS to molecular oxygen and thereby preventing accumulation of reactive oxygen species. A complex landscape of conformations is required for nNOS catalysis beyond the simple models derived from static crystal structures of nNOS reductase. Detailed understanding of this landscape advances our understanding of nNOS catalysis/electron transfer, and could provide new opportunities for the discovery of small molecule inhibitors that bind at dynamic protein interfaces of this multidimensional energy landscape.
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Affiliation(s)
- Anna Sobolewska-Stawiarz
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nicole G H Leferink
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Karl Fisher
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Derren J Heyes
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Sam Hay
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Stephen E J Rigby
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Nigel S Scrutton
- From the Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, Manchester M1 7DN, United Kingdom.
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Schmiesing J, Schlüter H, Ullrich K, Braulke T, Mühlhausen C. Interaction of glutaric aciduria type 1-related glutaryl-CoA dehydrogenase with mitochondrial matrix proteins. PLoS One 2014; 9:e87715. [PMID: 24498361 PMCID: PMC3912011 DOI: 10.1371/journal.pone.0087715] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/02/2014] [Indexed: 01/15/2023] Open
Abstract
Glutaric aciduria type 1 (GA1) is an inherited neurometabolic disorder caused by mutations in the GCDH gene encoding glutaryl-CoA dehydrogenase (GCDH), which forms homo- and heteromeric complexes in the mitochondrial matrix. GA1 patients are prone to the development of encephalopathic crises which lead to an irreversible disabling dystonic movement disorder. The clinical and biochemical manifestations of GA1 vary considerably and lack correlations to the genotype. Using an affinity chromatography approach we report here for the first time on the identification of mitochondrial proteins interacting directly with GCDH. Among others, dihydrolipoamide S-succinyltransferase (DLST) involved in the formation of glutaryl-CoA, and the β-subunit of the electron transfer flavoprotein (ETFB) serving as electron acceptor, were identified as GCDH binding partners. We have adapted the yellow fluorescent protein-based fragment complementation assay and visualized the oligomerization of GCDH as well as its direct interaction with DLST and ETFB in mitochondria of living cells. These data suggest that GCDH is a constituent of multimeric mitochondrial dehydrogenase complexes, and the characterization of their interrelated functions may provide new insights into the regulation of lysine oxidation and the pathophysiology of GA1.
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Affiliation(s)
- Jessica Schmiesing
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hartmut Schlüter
- Department of Clinical Chemistry, Laboratory for Mass Spectrometric Proteomics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kurt Ullrich
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Braulke
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (TB); (CM)
| | - Chris Mühlhausen
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail: (TB); (CM)
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Chowdhury NP, Mowafy AM, Demmer JK, Upadhyay V, Koelzer S, Jayamani E, Kahnt J, Hornung M, Demmer U, Ermler U, Buckel W. Studies on the mechanism of electron bifurcation catalyzed by electron transferring flavoprotein (Etf) and butyryl-CoA dehydrogenase (Bcd) of Acidaminococcus fermentans. J Biol Chem 2013; 289:5145-57. [PMID: 24379410 DOI: 10.1074/jbc.m113.521013] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Electron bifurcation is a fundamental strategy of energy coupling originally discovered in the Q-cycle of many organisms. Recently a flavin-based electron bifurcation has been detected in anaerobes, first in clostridia and later in acetogens and methanogens. It enables anaerobic bacteria and archaea to reduce the low-potential [4Fe-4S] clusters of ferredoxin, which increases the efficiency of the substrate level and electron transport phosphorylations. Here we characterize the bifurcating electron transferring flavoprotein (EtfAf) and butyryl-CoA dehydrogenase (BcdAf) of Acidaminococcus fermentans, which couple the exergonic reduction of crotonyl-CoA to butyryl-CoA to the endergonic reduction of ferredoxin both with NADH. EtfAf contains one FAD (α-FAD) in subunit α and a second FAD (β-FAD) in subunit β. The distance between the two isoalloxazine rings is 18 Å. The EtfAf-NAD(+) complex structure revealed β-FAD as acceptor of the hydride of NADH. The formed β-FADH(-) is considered as the bifurcating electron donor. As a result of a domain movement, α-FAD is able to approach β-FADH(-) by about 4 Å and to take up one electron yielding a stable anionic semiquinone, α-FAD, which donates this electron further to Dh-FAD of BcdAf after a second domain movement. The remaining non-stabilized neutral semiquinone, β-FADH(•), immediately reduces ferredoxin. Repetition of this process affords a second reduced ferredoxin and Dh-FADH(-) that converts crotonyl-CoA to butyryl-CoA.
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Affiliation(s)
- Nilanjan Pal Chowdhury
- From the Laboratorium für Mikrobiologie, Fachbereich Biologie and SYNMIKRO, Philipps-Universität, 35032 Marburg, Germany
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Moncoq K, Regad L, Mann S, Méjean A, Ploux O. Structure of the prolyl-acyl carrier protein oxidase involved in the biosynthesis of the cyanotoxin anatoxin-a. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:2340-52. [DOI: 10.1107/s0907444913021859] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 08/05/2013] [Indexed: 11/11/2022]
Abstract
Anatoxin-a and homoanatoxin-a are two potent cyanobacterial neurotoxins biosynthesized from L-proline by a short pathway involving polyketide synthases. Proline is first loaded onto AnaD, an acyl carrier protein, and prolyl-AnaD is then oxidized to 1-pyrroline-5-carboxyl-AnaD by a flavoprotein, AnaB. Three polyketide synthases then transform this imine into anatoxin-a or homoanatoxin-a. AnaB was crystallized in its holo form and its three-dimensional structure was determined by X-ray diffraction at 2.8 Å resolution. AnaB is a homotetramer and its fold is very similar to that of the acyl-CoA dehydrogenases (ACADs). The active-site base of AnaB, Glu244, superimposed very well with that of human isovaleryl-CoA dehydrogenase, confirming previous site-directed mutagenesis experiments and mechanistic proposals. The substrate-binding site of AnaB is small and is likely to be fitted for the pyrrolidine ring of proline. However, in contrast to ACADs, which use an electron-transport protein, AnaB uses molecular oxygen as the electron acceptor, as in acyl-CoA oxidases. Calculation of the solvent-accessible surface area around the FAD in AnaB and in several homologues showed that it is significantly larger in AnaB than in its homologues. A protonated histidine near the FAD in AnaB is likely to participate in oxygen activation. Furthermore, an array of water molecules detected in the AnaB structure suggests a possible path for molecular oxygen towards FAD. This is consistent with AnaB being an oxidase rather than a dehydrogenase. The structure of AnaB is the first to be described for a prolyl-ACP oxidase and it will contribute to defining the structural basis responsible for oxygen reactivity in flavoenzymes.
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Bharathi SS, Zhang Y, Mohsen AW, Uppala R, Balasubramani M, Schreiber E, Uechi G, Beck ME, Rardin MJ, Vockley J, Verdin E, Gibson BW, Hirschey MD, Goetzman ES. Sirtuin 3 (SIRT3) protein regulates long-chain acyl-CoA dehydrogenase by deacetylating conserved lysines near the active site. J Biol Chem 2013; 288:33837-33847. [PMID: 24121500 DOI: 10.1074/jbc.m113.510354] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Long-chain acyl-CoA dehydrogenase (LCAD) is a key mitochondrial fatty acid oxidation enzyme. We previously demonstrated increased LCAD lysine acetylation in SIRT3 knockout mice concomitant with reduced LCAD activity and reduced fatty acid oxidation. To study the effects of acetylation on LCAD and determine sirtuin 3 (SIRT3) target sites, we chemically acetylated recombinant LCAD. Acetylation impeded substrate binding and reduced catalytic efficiency. Deacetylation with recombinant SIRT3 partially restored activity. Residues Lys-318 and Lys-322 were identified as SIRT3-targeted lysines. Arginine substitutions at Lys-318 and Lys-322 prevented the acetylation-induced activity loss. Lys-318 and Lys-322 flank residues Arg-317 and Phe-320, which are conserved among all acyl-CoA dehydrogenases and coordinate the enzyme-bound FAD cofactor in the active site. We propose that acetylation at Lys-318/Lys-322 causes a conformational change which reduces hydride transfer from substrate to FAD. Medium-chain acyl-CoA dehydrogenase and acyl-CoA dehydrogenase 9, two related enzymes with lysines at positions equivalent to Lys-318/Lys-322, were also efficiently deacetylated by SIRT3 following chemical acetylation. These results suggest that acetylation/deacetylation at Lys-318/Lys-322 is a mode of regulating fatty acid oxidation. The same mechanism may regulate other acyl-CoA dehydrogenases.
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Affiliation(s)
- Sivakama S Bharathi
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Yuxun Zhang
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Al-Walid Mohsen
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Radha Uppala
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Manimalha Balasubramani
- Genomics and Proteomics Core Facility, University of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Emanuel Schreiber
- Genomics and Proteomics Core Facility, University of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Guy Uechi
- Genomics and Proteomics Core Facility, University of Pittsburgh, Pittsburgh, Pennsylvania 15224
| | - Megan E Beck
- Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania 15224
| | | | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224; Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania 15224
| | - Eric Verdin
- Gladstone Institutes and University of California, San Francisco, California 94158
| | | | - Matthew D Hirschey
- Sarah W. Stedman Nutrition and Metabolism Center Duke University, Medical Center, Durham, North Carolina 27704
| | - Eric S Goetzman
- Department of Pediatrics, University of Pittsburgh School of Medicine, University of Pittsburgh, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15224; Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania 15224.
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Schürmann M, Deters A, Wübbeler JH, Steinbüchel A. A novel 3-sulfinopropionyl coenzyme A (3SP-CoA) desulfinase from Advenella mimigardefordensis strain DPN7T acting as a key enzyme during catabolism of 3,3'-dithiodipropionic acid is a member of the acyl-CoA dehydrogenase superfamily. J Bacteriol 2013; 195:1538-51. [PMID: 23354747 PMCID: PMC3624521 DOI: 10.1128/jb.02105-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 01/17/2013] [Indexed: 01/28/2023] Open
Abstract
3-Sulfinopropionyl coenzyme A (3SP-CoA) desulfinase (AcdDPN7) is a new desulfinase that catalyzes the sulfur abstraction from 3SP-CoA in the betaproteobacterium Advenella mimigardefordensis strain DPN7(T). During investigation of a Tn5::mob-induced mutant defective in growth on 3,3'-dithiodipropionate (DTDP) and also 3-sulfinopropionate (3SP), the transposon insertion was mapped to an open reading frame with the highest homology to an acyl-CoA dehydrogenase (Acd) from Burkholderia phenoliruptrix strain BR3459a (83% identical and 91% similar amino acids). An A. mimigardefordensis Δacd mutant was generated and verified the observed phenotype of the Tn5::mob-induced mutant. For enzymatic studies, AcdDPN7 was heterologously expressed in Escherichia coli BL21(DE3)/pLysS by using pET23a::acdDPN7. The purified protein is yellow and contains a noncovalently bound flavin adenine dinucleotide (FAD) cofactor, as verified by high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) analyses. Size-exclusion chromatography revealed a native molecular mass of about 173 kDa, indicating a homotetrameric structure (theoretically 179 kDa), which is in accordance with other members of the acyl-CoA dehydrogenase superfamily. In vitro assays unequivocally demonstrated that the purified enzyme converted 3SP-CoA into propionyl-CoA and sulfite (SO3(2-)). Kinetic studies of AcdDPN7 revealed a Vmax of 4.19 μmol min(-1) mg(-1), an apparent Km of 0.013 mM, and a kcat/Km of 240.8 s(-1) mM(-1) for 3SP-CoA. However, AcdDPN7 is unable to perform a dehydrogenation, which is the usual reaction catalyzed by members of the acyl-CoA dehydrogenase superfamily. Comparison to other known desulfinases showed a comparably high catalytic efficiency of AcdDPN7 and indicated a novel reaction mechanism. Hence, AcdDPN7 encodes a new desulfinase based on an acyl-CoA dehydrogenase (EC 1.3.8.x) scaffold. Concomitantly, we identified the gene product that is responsible for the final desulfination step during catabolism of 3,3'-dithiodipropionate (DTDP), a sulfur-containing precursor substrate for biosynthesis of polythioesters.
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Affiliation(s)
- Marc Schürmann
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Anika Deters
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Jan Hendrik Wübbeler
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
- Environmental Sciences Department, King Abdulaziz University, Jeddah, Saudi Arabia
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Hamill MJ, Jost M, Wong C, Bene NC, Drennan CL, Elliott SJ. Electrochemical characterization of Escherichia coli adaptive response protein AidB. Int J Mol Sci 2012; 13:16899-915. [PMID: 23443126 PMCID: PMC3546729 DOI: 10.3390/ijms131216899] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 11/26/2012] [Accepted: 12/03/2012] [Indexed: 11/16/2022] Open
Abstract
When exposed to known DNA-damaging alkylating agents, Escherichia coli cells increase production of four DNA repair enzymes: Ada, AlkA, AlkB, and AidB. The role of three enzymes (Ada, AlkA, and AlkB) in repairing DNA lesions has been well characterized, while the function of AidB is poorly understood. AidB has a distinct cofactor that is potentially related to the elusive role of AidB in adaptive response: a redox active flavin adenine dinucleotide (FAD). In this study, we report the thermodynamic redox properties of the AidB flavin for the first time, both for free protein and in the presence of potential substrates. We find that the midpoint reduction potential of the AidB flavin is within a biologically relevant window for redox chemistry at -181 mV, that AidB significantly stabilizes the flavin semiquinone, and that small molecule binding perturbs the observed reduction potential. Our electrochemical results combined with structural analysis allow for fresh comparisons between AidB and the homologous acyl-coenzyme A dehydrogenase (ACAD) family of enzymes. AidB exhibits several discrepancies from ACADs that suggest a novel catalytic mechanism distinct from that of the ACAD family enzymes.
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Affiliation(s)
- Michael J. Hamill
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA; E-Mails: (M.J.H.); (N.C.B.)
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA; E-Mails: (M.J.); (C.L.D.)
| | - Marco Jost
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA; E-Mails: (M.J.); (C.L.D.)
| | - Cintyu Wong
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA; E-Mails: (M.J.); (C.L.D.)
| | - Nicholas C. Bene
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA; E-Mails: (M.J.H.); (N.C.B.)
| | - Catherine L. Drennan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA; E-Mails: (M.J.); (C.L.D.)
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Center for Environmental Health, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sean J. Elliott
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA; E-Mails: (M.J.H.); (N.C.B.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-617-358-2816; Fax: +1-617-353-6466
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Isackson PJ, Sutton KA, Hostetler KY, Vladutiu GD. Novel mutations in the gene encoding very long-chain acyl-CoA dehydrogenase identified in patients with partial carnitine palmitoyltransferase II deficiency. Muscle Nerve 2012; 47:224-9. [PMID: 23169530 DOI: 10.1002/mus.23498] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2012] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Twenty-six patients with clinical symptoms of adult onset carnitine palmitoyltransferase II (CPTII) deficiency were examined. All patients had skeletal muscle CPTII enzyme activity levels indicative of heterozygosity for CPT2 mutations, however sequence analysis identified no pathogenic mutations within the CPT2 gene. METHODS Because the reaction product of CPTII is the substrate for very long-chain acyl-CoA dehydrogenase (VLCAD), we examined the ACADVL gene in these patients by sequence analysis. RESULTS Missense mutations within the ACADVL gene were identified in 3 of the patients. CONCLUSIONS The locations of the altered amino acid residues within the crystal structure of VLCAD are on the surface of the molecule and may be involved in interactions with neighboring molecules. These findings support the importance of considering that mutations may be present in the ACADVL gene when a significant partial deficiency is found in CPTII activity, but no mutations in the CPT2 gene can be identified.
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Affiliation(s)
- Paul J Isackson
- Department of Pediatrics, University at Buffalo, Buffalo, New York, USA.
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Crystal structure of the Leishmania major peroxidase-cytochrome c complex. Proc Natl Acad Sci U S A 2012; 109:18390-4. [PMID: 23100535 DOI: 10.1073/pnas.1213295109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The causative agent of leishmaniasis is the protozoan parasite Leishmania major. Part of the host protective mechanism is the production of reactive oxygen species including hydrogen peroxide. In response, L. major produces a peroxidase, L. major peroxidase (LmP), that helps to protect the parasite from oxidative stress. LmP is a heme peroxidase that catalyzes the peroxidation of mitochondrial cytochrome c. We have determined the crystal structure of LmP in a complex with its substrate, L. major cytochrome c (LmCytc) to 1.84 Å, and compared the structure to its close homolog, the yeast cytochrome c peroxidase-cytochrome c complex. The binding interface between LmP and LmCytc has one strong and one weak ionic interaction that the yeast system lacks. The differences between the steady-state kinetics correlate well with the Lm redox pair being more dependent on ionic interactions, whereas the yeast redox pair depends more on nonpolar interactions. Mutagenesis studies confirm that the ion pairs at the intermolecular interface are important to both k(cat) and K(M). Despite these differences, the electron transfer path, with respect to the distance between hemes, along the polypeptide chain is exactly the same in both redox systems. A potentially important difference, however, is the side chains involved. LmP has more polar groups (Asp and His) along the pathway compared with the nonpolar groups (Leu and Ala) in the yeast system, and as a result, the electrostatic environment along the presumed electron transfer path is substantially different.
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47
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Covian R, Balaban RS. Cardiac mitochondrial matrix and respiratory complex protein phosphorylation. Am J Physiol Heart Circ Physiol 2012; 303:H940-66. [PMID: 22886415 DOI: 10.1152/ajpheart.00077.2012] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
It has become appreciated over the last several years that protein phosphorylation within the cardiac mitochondrial matrix and respiratory complexes is extensive. Given the importance of oxidative phosphorylation and the balance of energy metabolism in the heart, the potential regulatory effect of these classical signaling events on mitochondrial function is of interest. However, the functional impact of protein phosphorylation and the kinase/phosphatase system responsible for it are relatively unknown. Exceptions include the well-characterized pyruvate dehydrogenase and branched chain α-ketoacid dehydrogenase regulatory system. The first task of this review is to update the current status of protein phosphorylation detection primarily in the matrix and evaluate evidence linking these events with enzymatic function or protein processing. To manage the scope of this effort, we have focused on the pathways involved in energy metabolism. The high sensitivity of modern methods of detecting protein phosphorylation and the low specificity of many kinases suggests that detection of protein phosphorylation sites without information on the mole fraction of phosphorylation is difficult to interpret, especially in metabolic enzymes, and is likely irrelevant to function. However, several systems including protein translocation, adenine nucleotide translocase, cytochrome c, and complex IV protein phosphorylation have been well correlated with enzymatic function along with the classical dehydrogenase systems. The second task is to review the current understanding of the kinase/phosphatase system within the matrix. Though it is clear that protein phosphorylation occurs within the matrix, based on (32)P incorporation and quantitative mass spectrometry measures, the kinase/phosphatase system responsible for this process is ill-defined. An argument is presented that remnants of the much more labile bacterial protein phosphoryl transfer system may be present in the matrix and that the evaluation of this possibility will require the application of approaches developed for bacterial cell signaling to the mitochondria.
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Affiliation(s)
- Raul Covian
- Laboratory of Cardiac Energetics, National Heart Lung and Blood Institute, Bethesda, Maryland 20817, USA
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Rodrigues JV, Gomes CM. Mechanism of superoxide and hydrogen peroxide generation by human electron-transfer flavoprotein and pathological variants. Free Radic Biol Med 2012; 53:12-9. [PMID: 22588007 DOI: 10.1016/j.freeradbiomed.2012.04.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species production by mitochondrial enzymes plays a fundamental role both in cellular signaling and in the progression of dysfunctional states. However, sources of reactive oxygen species and the mechanisms by which enzymes produce these reactive species still remain elusive. We characterized the generation of reactive oxygen species by purified human electron-transfer flavoprotein (ETF), a mitochondrial enzyme that has a central role in the metabolism of lipids, amino acids, and choline. The results showed that ETF produces significant amounts of both superoxide and hydrogen peroxide in the presence of its partner enzyme medium-chain acyl-CoA dehydrogenase (MCAD). ETF-mediated production of reactive oxygen species is partially inhibited at high MCAD/ETF ratios, whereas it is enhanced at high ionic strength. Determination of the reduction potentials of ETF showed that thermodynamic properties of the FAD cofactor are changed upon formation of a complex between ETF and MCAD, supporting the notion that protein:protein interactions modulate the reactivity of the protein with dioxygen. Two pathogenic ETF variants were also studied to determine which factors modulate the reactivity toward molecular oxygen and promote reactive oxygen species production. The results obtained show that destabilized conformations and defective protein:protein interactions increase the ability of ETF to generate reactive oxygen species. A possible role for these processes in mitochondrial dysfunction in metabolic disorders of fatty acid β-oxidation is discussed.
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Affiliation(s)
- João V Rodrigues
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
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Keeler AM, Flotte TR. Cell and gene therapy for genetic diseases: inherited disorders affecting the lung and those mimicking sudden infant death syndrome. Hum Gene Ther 2012; 23:548-56. [PMID: 22642257 PMCID: PMC3392613 DOI: 10.1089/hum.2012.087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 05/29/2012] [Indexed: 12/20/2022] Open
Abstract
Some of the first human gene therapy trials targeted diseases of the lung and provided important information that will continue to help shape future trials. Here we describe both cell and gene therapies for lung diseases such as cystic fibrosis and alpha-1 antitrypsin disorder as well as fatty acid oxidation disorders that mimic sudden infant death syndrome (SIDS). Human clinical gene therapy trials for cystic fibrosis and alpha-1 antitrypsin have been performed using a variety of vectors including adenovirus, adeno-associated virus, and nonviral vectors. No human clinical gene therapy trials have been performed for disorders of fatty acid oxidation; however, important proof-of-principle studies have been completed for multiple fatty acid oxidation disorders. Important achievements have been made and have yet to come for cell and gene therapies for disorders of the lung and those mimicking SIDS.
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Affiliation(s)
- Allison M Keeler
- Gene Therapy Center and Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Feng J, Kweon O, Xu H, Cerniglia CE, Chen H. Probing the NADH- and Methyl Red-binding site of a FMN-dependent azoreductase (AzoA) from Enterococcus faecalis. Arch Biochem Biophys 2012; 520:99-107. [PMID: 22387379 DOI: 10.1016/j.abb.2012.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 12/31/2022]
Abstract
AzoA from Enterococcus faecalis is a member of the polymeric flavin-dependent NADH-preferred azoreductase group. Little is known about the binding and interaction of NADH and azo dye in the azoreductase group. A synergetic strategy based on computational prediction, reverse genetics validation coupled with site-directed mutagenesis, and reconstruction of mutation network was used to investigate the binding and interaction of NADH and a model azo dye, Methyl Red, with AzoA. Methyl Red and NADH interacted in a unique binding mode in which the benzoic acid moiety of Methyl Red and the nicotinamide ring of NADH were not parallel to the flavin isoalloxazine ring, but lay against it at angles of ∼45° and ∼35°, respectively. The adenine ribose moiety of NADH was surrounded by loop ℓ2 on chain B and α3 on chain A in a typical Rossmann fold. There were 12 and 19 amino acid residues that could participate in the binding of Methyl Red and NADH, respectively, especially the residues Tyr-129 and Asp-184. The functional perturbation effects of 13 residues, including Tyr-129 and Asp-184, were mapped to reconstruct the mutation network, which confirmed the proposed binding modes and also provided insights into the interaction among NADH, FMN and Methyl Red.
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Affiliation(s)
- Jinhui Feng
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States
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