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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: 0] [Impact Index Per Article: 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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2
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How an assembly factor enhances covalent FAD attachment to the flavoprotein subunit of complex II. J Biol Chem 2022; 298:102472. [PMID: 36089066 PMCID: PMC9557727 DOI: 10.1016/j.jbc.2022.102472] [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] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 01/25/2023] Open
Abstract
The membrane-bound complex II family of proteins is composed of enzymes that catalyze succinate and fumarate interconversion coupled with reduction or oxidation of quinones within the membrane domain. The majority of complex II enzymes are protein heterotetramers with the different subunits harboring a variety of redox centers. These redox centers are used to transfer electrons between the site of succinate-fumarate oxidation/reduction and the membrane domain harboring the quinone. A covalently bound FAD cofactor is present in the flavoprotein subunit, and the covalent flavin linkage is absolutely required to enable the enzyme to oxidize succinate. Assembly of the covalent flavin linkage in eukaryotic cells and many bacteria requires additional protein assembly factors. Here, we provide mechanistic details for how the assembly factors work to enhance covalent flavinylation. Both prokaryotic SdhE and mammalian SDHAF2 enhance FAD binding to their respective apoprotein of complex II. These assembly factors also increase the affinity for dicarboxylates to the apoprotein-noncovalent FAD complex and stabilize the preassembly complex. These findings are corroborated by previous investigations of the roles of SdhE in enhancing covalent flavinylation in both bacterial succinate dehydrogenase and fumarate reductase flavoprotein subunits and of SDHAF2 in performing the same function for the human mitochondrial succinate dehydrogenase flavoprotein. In conclusion, we provide further insight into assembly factor involvement in building complex II flavoprotein subunit active site required for succinate oxidation.
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The roles of SDHAF2 and dicarboxylate in covalent flavinylation of SDHA, the human complex II flavoprotein. Proc Natl Acad Sci U S A 2020; 117:23548-23556. [PMID: 32887801 DOI: 10.1073/pnas.2007391117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial complex II, also known as succinate dehydrogenase (SDH), is an integral-membrane heterotetramer (SDHABCD) that links two essential energy-producing processes, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. A significant amount of information is available on the structure and function of mature complex II from a range of organisms. However, there is a gap in our understanding of how the enzyme assembles into a functional complex, and disease-associated complex II insufficiency may result from incorrect function of the mature enzyme or from assembly defects. Here, we investigate the assembly of human complex II by combining a biochemical reconstructionist approach with structural studies. We report an X-ray structure of human SDHA and its dedicated assembly factor SDHAF2. Importantly, we also identify a small molecule dicarboxylate that acts as an essential cofactor in this process and works in synergy with SDHAF2 to properly orient the flavin and capping domains of SDHA. This reorganizes the active site, which is located at the interface of these domains, and adjusts the pKa of SDHAR451 so that covalent attachment of the flavin adenine dinucleotide (FAD) cofactor is supported. We analyze the impact of disease-associated SDHA mutations on assembly and identify four distinct conformational forms of the complex II flavoprotein that we assign to roles in assembly and catalysis.
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Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
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Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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Quantification of the Metabolic State in Cell-Model of Parkinson's Disease by Fluorescence Lifetime Imaging Microscopy. Sci Rep 2016; 6:19145. [PMID: 26758390 PMCID: PMC4725947 DOI: 10.1038/srep19145] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/07/2015] [Indexed: 12/17/2022] Open
Abstract
Intracellular endogenous fluorescent co-enzymes, reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), play a pivotal role in cellular metabolism; quantitative assessment of their presence in living cells can be exploited to monitor cellular energetics in Parkinson's disease (PD), a neurodegenerative disorder. Here, we applied two-photon fluorescence lifetime imaging microscopy (2P-FLIM) to noninvasively measure the fluorescence lifetime components of NADH and FAD, and their relative contributions in MPP(+) (1-methyl-4-phenylpyridinium) treated neuronal cells, derived from PC12 cells treated with nerve growth factor (NGF), to mimic PD conditions. A systematic FLIM data analysis showed a statistically significant (p < 0.001) decrease in the fluorescence lifetime of both free and protein-bound NADH, as well as free and protein-bound FAD in MPP(+) treated cells. On the relative contributions of the free and protein-bound NADH and FAD to the life time, however, both the free NADH contribution and the corresponding protein-bound FAD contribution increase significantly (p < 0.001) in MPP(+) treated cells, compared to control cells. These results, which indicate a shift in energy production in the MPP(+) treated cells from oxidative phosphorylation towards anaerobic glycolysis, can potentially be used as cellular metabolic metrics to assess the condition of PD at the cellular level.
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Maklashina E, Rajagukguk S, Starbird CA, McDonald WH, Koganitsky A, Eisenbach M, Iverson TM, Cecchini G. Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II. J Biol Chem 2015; 291:2904-16. [PMID: 26644464 DOI: 10.1074/jbc.m115.690396] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Indexed: 01/23/2023] Open
Abstract
Escherichia coli harbors two highly conserved homologs of the essential mitochondrial respiratory complex II (succinate:ubiquinone oxidoreductase). Aerobically the bacterium synthesizes succinate:quinone reductase as part of its respiratory chain, whereas under microaerophilic conditions, the quinol:fumarate reductase can be utilized. All complex II enzymes harbor a covalently bound FAD co-factor that is essential for their ability to oxidize succinate. In eukaryotes and many bacteria, assembly of the covalent flavin linkage is facilitated by a small protein assembly factor, termed SdhE in E. coli. How SdhE assists with formation of the covalent flavin bond and how it binds the flavoprotein subunit of complex II remain unknown. Using photo-cross-linking, we report the interaction site between the flavoprotein of complex II and the SdhE assembly factor. These data indicate that SdhE binds to the flavoprotein between two independently folded domains and that this binding mode likely influences the interdomain orientation. In so doing, SdhE likely orients amino acid residues near the dicarboxylate and FAD binding site, which facilitates formation of the covalent flavin linkage. These studies identify how the conserved SdhE assembly factor and its homologs participate in complex II maturation.
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Affiliation(s)
- Elena Maklashina
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121, the Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158
| | - Sany Rajagukguk
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121
| | | | - W Hayes McDonald
- the Department of Biochemistry and Mass Spectrometry Research Center
| | - Anna Koganitsky
- the Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Michael Eisenbach
- the Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Tina M Iverson
- the Department of Biochemistry and Mass Spectrometry Research Center, the Department of Pharmacology, the Center for Structural Biology, and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, and
| | - Gary Cecchini
- From the Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121, the Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158,
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Kim HJ, Winge DR. Emerging concepts in the flavinylation of succinate dehydrogenase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:627-36. [PMID: 23380393 DOI: 10.1016/j.bbabio.2013.01.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/28/2022]
Abstract
The Succinate Dehydrogenase (SDH) heterotetrameric complex catalyzes the oxidation of succinate to fumarate in the tricarboxylic acid (TCA) cycle and in the aerobic respiratory chains of eukaryotes and bacteria. Essential in this catalysis is the covalently-linked cofactor flavin adenine dinucleotide (FAD) in subunit1 (Sdh1) of the SDH enzyme complex. The mechanism of FAD insertion and covalent attachment to Sdh1 is unknown. Our working concept of this flavinylation process has relied mostly on foundational works from the 1990s and by applying the principles learned from other enzymes containing a similarly linked FAD. The discovery of the flavinylation factor Sdh5, however, has provided new insight into the possible mechanism associated with Sdh1 flavinylation. This review focuses on encapsulating prior and recent advances towards understanding the mechanism associated with flavinylation of Sdh1 and how this flavinylation process affects the overall assembly of SDH. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- Hyung J Kim
- Department of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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Scalliet G, Bowler J, Luksch T, Kirchhofer-Allan L, Steinhauer D, Ward K, Niklaus M, Verras A, Csukai M, Daina A, Fonné-Pfister R. Mutagenesis and functional studies with succinate dehydrogenase inhibitors in the wheat pathogen Mycosphaerella graminicola. PLoS One 2012; 7:e35429. [PMID: 22536383 PMCID: PMC3334918 DOI: 10.1371/journal.pone.0035429] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 03/16/2012] [Indexed: 02/03/2023] Open
Abstract
A range of novel carboxamide fungicides, inhibitors of the succinate dehydrogenase enzyme (SDH, EC 1.3.5.1) is currently being introduced to the crop protection market. The aim of this study was to explore the impact of structurally distinct carboxamides on target site resistance development and to assess possible impact on fitness. We used a UV mutagenesis approach in Mycosphaerella graminicola, a key pathogen of wheat to compare the nature, frequencies and impact of target mutations towards five subclasses of carboxamides. From this screen we identified 27 amino acid substitutions occurring at 18 different positions on the 3 subunits constituting the ubiquinone binding (Qp) site of the enzyme. The nature of substitutions and cross resistance profiles indicated significant differences in the binding interaction to the enzyme across the different inhibitors. Pharmacophore elucidation followed by docking studies in a tridimensional SDH model allowed us to propose rational hypotheses explaining some of the differential behaviors for the first time. Interestingly all the characterized substitutions had a negative impact on enzyme efficiency, however very low levels of enzyme activity appeared to be sufficient for cell survival. In order to explore the impact of mutations on pathogen fitness in vivo and in planta, homologous recombinants were generated for a selection of mutation types. In vivo, in contrast to previous studies performed in yeast and other organisms, SDH mutations did not result in a major increase of reactive oxygen species levels and did not display any significant fitness penalty. However, a number of Qp site mutations affecting enzyme efficiency were shown to have a biological impact in planta. Using the combined approaches described here, we have significantly improved our understanding of possible resistance mechanisms to carboxamides and performed preliminary fitness penalty assessment in an economically important plant pathogen years ahead of possible resistance development in the field.
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Heuts DPHM, Scrutton NS, McIntire WS, Fraaije MW. What's in a covalent bond? On the role and formation of covalently bound flavin cofactors. FEBS J 2009; 276:3405-27. [PMID: 19438712 DOI: 10.1111/j.1742-4658.2009.07053.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many enzymes use one or more cofactors, such as biotin, heme, or flavin. These cofactors may be bound to the enzyme in a noncovalent or covalent manner. Although most flavoproteins contain a noncovalently bound flavin cofactor (FMN or FAD), a large number have these cofactors covalently linked to the polypeptide chain. Most covalent flavin-protein linkages involve a single cofactor attachment via a histidyl, tyrosyl, cysteinyl or threonyl linkage. However, some flavoproteins contain a flavin that is tethered to two amino acids. In the last decade, many studies have focused on elucidating the mechanism(s) of covalent flavin incorporation (flavinylation) and the possible role(s) of covalent protein-flavin bonds. These endeavors have revealed that covalent flavinylation is a post-translational and self-catalytic process. This review presents an overview of the known types of covalent flavin bonds and the proposed mechanisms and roles of covalent flavinylation.
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Affiliation(s)
- Dominic P H M Heuts
- Laboratory of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands
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10
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Kim EJ, Kim JS, Lee IH, Rhee HJ, Lee JK. Superoxide generation by chlorophyllide a reductase of Rhodobacter sphaeroides. J Biol Chem 2007; 283:3718-30. [PMID: 18079120 DOI: 10.1074/jbc.m707774200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chlorophyllide a reductase of Rhodobacter sphaeroides, which were reconstituted with the purified subunits of BchX, BchY, and BchZ, reduced ring B of chlorophyllide a using NADH under anaerobic conditions. Interestingly, suppressor mutations rescuing the inability of R. sphaeroides Fe-SOD mutant to grow in succinate-based minimal medium were predominantly mapped to BchZ subunit of chlorophyllide a reductase. The enzyme is labile in the presence of O(2). However, it generates superoxide at low O(2). The enzymes reconstituted with BchX, BchY, and the mutein subunit of BchZ from suppressor mutants showed less activity not only for chlorophyllide a reduction but also for superoxide generation compared with the enzyme reconstituted with the wild-type subunits. BchX, which contains FMN, and BchY are iron-sulfur proteins, whereas BchZ is a hemoprotein containing b-type heme. Neither chlorophyllide a reduction nor superoxide generation was observed with the enzyme reconstituted with the wild-type subunits of BchX and BchY, and the apo-subunit of BchZ that had been refolded without heme, in which FMN of BchX was fully reduced. Thus, superoxide is generated not from FMN of BchX but from heme of BchZ. Consistently, the heme of BchZ muteins was half-reduced in its redox state compared with that of wild-type BchZ.
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Affiliation(s)
- Eui-Jin Kim
- Department of Life Science and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul 121-742, Korea
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Tomasiak TM, Cecchini G, Iverson TM. Succinate as Donor; Fumarate as Acceptor. EcoSal Plus 2007; 2. [PMID: 26443593 DOI: 10.1128/ecosal.3.2.6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Indexed: 06/05/2023]
Abstract
Succinate and fumarate are four-carbon dicarboxylates that differ in the identity of their central bond (single or double). The oxidoreduction of these small molecules plays a central role in both aerobic and anaerobic respiration. During aerobic respiration, succinate is oxidized, donating two reducing equivalents, while in anaerobic respiration, fumarate is reduced, accepting two reducing equivalents. Two related integral membrane Complex II superfamily members catalyze these reactions, succinate:ubiquinone oxidoreductase (SQR) and fumarate:menaquinol oxidoreductase (QFR). The structure, function, and regulation of these integral-membrane enzymes are summarized here. The overall architecture of these Complex II enzymes has been found to consist of four subunits: two integral membrane subunits, and a soluble domain consisting of an iron-sulfur protein subunit, and a flavoprotein subunit. This architecture provides a scaffold that houses one active site in the membrane and another in the soluble milieu, making a linear electron transfer chain that facilities shuttling of reducing equivalents between the two active sites. A combination of kinetic measurements, mutagenesis, electron paramagnetic resonance spectroscopy, UV/Vis spectroscopy, and x-ray crystallography have suggested mechanisms for succinate:fumarate interconversion, electron transfer, and quinone:quinol interconversion. Of particular interest are the structural details that control directionality and make SQR and QFR primed for preferential catalysis each in different favored directions.
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12
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Singer TP, Kearney EB, Kenney WC. Succinate dehydrogenase. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 37:189-272. [PMID: 4570066 DOI: 10.1002/9780470122822.ch4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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King TE. Reconstitution of the respiratory chain. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 28:155-236. [PMID: 5334060 DOI: 10.1002/9780470122730.ch3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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14
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Singer TP. Determination of the activity of succinate, NADH, choline, and alpha-glycerophosphate dehydrogenases. METHODS OF BIOCHEMICAL ANALYSIS 2006; 22:123-75. [PMID: 4155042 DOI: 10.1002/9780470110423.ch3] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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Caldinelli L, Iametti S, Barbiroli A, Bonomi F, Fessas D, Molla G, Pilone MS, Pollegioni L. Dissecting the structural determinants of the stability of cholesterol oxidase containing covalently bound flavin. J Biol Chem 2005; 280:22572-81. [PMID: 15817448 DOI: 10.1074/jbc.m500549200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cholesterol oxidase from Brevibacterium sterolicum is a monomeric flavoenzyme catalyzing the oxidation and isomerization of cholesterol to cholest-4-en-3-one. This protein is a class II cholesterol oxidases, with the FAD cofactor covalently linked to the enzyme through the His(69) residue. In this work, unfolding of wild-type cholesterol oxidase was compared with that of a H69A mutant, which does not covalently bind the flavin cofactor. The two protein forms do not show significant differences in their overall topology, but the urea-induced unfolding of the H69A mutant occurred at significant lower urea concentrations than wild-type (approximately 3 versus approximately 5 M, respectively), and the mutant protein had a melting temperature approximately 10-15 degrees C lower than wild-type in thermal denaturation experiments. The different sensitivity of the various spectroscopic features used to monitor protein unfolding indicated that in both proteins a two-step (three-state) process occurs. The presence of an intermediate was more evident for the H69A mutant at 2 m urea, where catalytic activity and tertiary structure were lost, and new hydrophobic patches were exposed on the protein surface, resulting in protein aggregation. Comparative analysis of the changes occurring upon urea and thermal treatment of the wild-type and H69A protein showed a good correlation between protein instability and the elimination of the covalent link between the flavin and the protein. This covalent bond represents a structural device to modify the flavin redox potentials and stabilize the tertiary structure of cholesterol oxidase, thus pointing to a specific meaning of the flavin binding mode in enzymes that carry out the same reaction in pathogenic versus non-pathogenic bacteria.
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Affiliation(s)
- Laura Caldinelli
- Department of Biotechnology and Molecular Sciences, University of Insubria, Varese, Italy
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Abstract
Complex II is the only membrane-bound component of the Krebs cycle and in addition functions as a member of the electron transport chain in mitochondria and in many bacteria. A recent X-ray structural solution of members of the complex II family of proteins has provided important insights into their function. One feature of the complex II structures is a linear electron transport chain that extends from the flavin and iron-sulfur redox cofactors in the membrane extrinsic domain to the quinone and b heme cofactors in the membrane domain. Exciting recent developments in relation to disease in humans and the formation of reactive oxygen species by complex II point to its overall importance in cellular physiology.
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Affiliation(s)
- Gary Cecchini
- Molecular Biology Division, Veterans Administration Medical Center, San Francisco, California 94121, USA.
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17
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LESTER RL, SMITH AL. Studies on the electron transport system. 28. The mode of reduction of tetrazolium salts by beef heart mitochondria; role of coenzyme Q and other lipids. ACTA ACUST UNITED AC 1998; 47:475-96. [PMID: 13761204 DOI: 10.1016/0006-3002(61)90543-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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De Francesco R, Edmondson DE. pKa values of the 8 alpha-imidazole substituents in selected flavoenzymes containing 8 alpha-histidylflavins. Arch Biochem Biophys 1988; 264:281-7. [PMID: 3395125 DOI: 10.1016/0003-9861(88)90595-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Difference absorption spectroscopy as a function of pH is described as a probe to determine the pKa values of the 8 alpha-imidazole substituent in flavoenzymes containing 8 alpha-histidylflavin coenzymes. Reversible absorption difference spectra are observed in the pH range 5.5 to 8.5 when synthetic 8 alpha-imidazolyl-FMN is bound to the apoflavodoxins from Azotobacter vinelandii and from Clostridium pasterianum. The observed spectral perturbations of these two flavodoxin complexes follow a single proton ionization dependence with respective pKa values of 6.7 and 6.8. No pH-induced spectral perturbations were observed when 8 alpha-(N-CH3)-imidazolium FMN was bound to either flavodoxin. Similar approaches are described to determine the 8 alpha-imidazolyl pKa values of the 8 alpha-histidyl-FAD coenzyme of the cholesterol oxidases from Schizophyllum commune and from Gleocystidium chrysocreas. Previous work has shown the former enzyme contains an 8 alpha-N1-histidyl-FAD (W. C. Kenney et al. (1979) J. Biol. Chem. 254, 4689-4690) while experiments reported here show the latter enzyme also contains one 8 alpha-N1-histidyl-FAD per mole of enzyme. The pKa value for the 8 alpha-imidazole substituent on the flavin of S. commune cholesterol oxidase is 5.4 while that determined for the G. chrysocreas enzyme is 6.2. These results demonstrate that the pKa of the 8 alpha-imidazole substituent can be determined in enzymes containing an 8 alpha-histidylflavin, provided that the enzyme is stable in the pH range required to observe ionization. Furthermore it is shown this the pKa value can differ even on comparison of enzymes from different sources that catalyze the same reaction.
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Affiliation(s)
- R De Francesco
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
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20
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Cole ST, Condon C, Lemire BD, Weiner JH. Molecular biology, biochemistry and bioenergetics of fumarate reductase, a complex membrane-bound iron-sulfur flavoenzyme of Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 811:381-403. [PMID: 3910107 DOI: 10.1016/0304-4173(85)90008-4] [Citation(s) in RCA: 139] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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21
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Beyer RE, Starnes JW. Coenzyme Q and Myocardial Function in Aging and Exercise. DEVELOPMENTS IN CARDIOVASCULAR MEDICINE 1985. [DOI: 10.1007/978-1-4613-2621-2_35] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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22
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Kim YS, Lambooy JP. Covalent bonding of riboflavin homologs by hepatic mitochondrial membrane enzymes. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1985; 17:975-81. [PMID: 4065409 DOI: 10.1016/0020-711x(85)90242-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Radioactive riboflavin and homologs of riboflavin possessing an ethyl group in positions 7- or 8-, or both were used to investigate the covalent bonding of the flavins. No strict correlation could be found between the location of the ethyl group and the activities of the enzymes known to be covalently-bound flavoproteins. It is proposed that the widely varying activities of these enzymes when utilizing certain homologs is the result of a combination of the abnormal flavin coenzyme and the differences in the specificity of the apoenzymes in the various tissues.
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Cook RJ, Misono KS, Wagner C. Identification of the covalently bound flavin of dimethylglycine dehydrogenase and sarcosine dehydrogenase from rat liver mitochondria. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90771-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Benavides J, Garcia ML, Valdivieso F, Gimenez-Gallego G. Ubiquinone, nonheme iron, and flavins in the renal brush border plasma membranes. Arch Biochem Biophys 1981; 206:451-3. [PMID: 7224647 DOI: 10.1016/0003-9861(81)90112-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Watanabe K, Minamiura N, Yasunobu KT. Thiols liberate covalently bonded flavin from monoamine oxidase. Biochem Biophys Res Commun 1980; 94:579-85. [PMID: 7396921 DOI: 10.1016/0006-291x(80)91271-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Singer TP, Edmondson DE. Structure, properties, and determination of covalently bound flavins. Methods Enzymol 1980; 66:253-64. [PMID: 7374473 DOI: 10.1016/0076-6879(80)66466-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Shinkai S, Mori K, Kusano Y, Manabe O. Enhanced Reactivity of a Flavin Bound to Quaternized Poly(4-vinylpyridine)via8-Position. A Model System of a Flavin Coenzyme Covalently-linked to Enzymest. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1979. [DOI: 10.1246/bcsj.52.3606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Weiner J, Dickie P. Fumarate reductase of Escherichia coli. Elucidation of the covalent-flavin component. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86933-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Pinto J, Wolinsky M, Rivlin RS. Chlorpromazine antagonism of thyroxine-induced flavin formation. Biochem Pharmacol 1979; 28:597-600. [PMID: 444247 DOI: 10.1016/0006-2952(79)90141-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Vinogradov AD, Grivennikova VG, Gavrikova EV. Studies on the succinate dehydrogenating system. I. Kinetics of the succinate dehydrogenase interaction with a semiquindiimine radical of N,N,N',N'-tetramethyl-p-phenylenediamine. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 545:141-54. [PMID: 31933 DOI: 10.1016/0005-2728(79)90121-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. The activities of the soluble reconstitutively active succinate dehydrogenase (EC 1.3.99.1) measured with three artificial electron acceptors, e.g. ferricyanide, phenazine methosulfate and free radical of N,N,N',N'-tetramethyl-p-phenylenediamine (WB), have been compared. The values estimated by extrapolation to infinite acceptor concentration using double reciprocal plots 1/v versus 1/[acceptor] are nearly the same for ferricyanide and phenazine methosulfate and about twice as high for the WB. 2. The double reciprocal plots 1/v versus 1/[succinate] in the presence of malonate at various concentrations of WB give a series of straight lines intercepting in the third quadrant. The data support the mechanism of the overall reaction, in which the reduced enzyme is oxidized by WB before dissociation of the enzyme-product complex. 3. The dependence of the rate of the overall reaction on WB concentration shows that only one kinetically significant redox site of the soluble succinate dehydrogenase is involved in the reduction of WB. 4. Studies of the change of V and Km values during aerobic inactivation of the soluble enzyme suggest that only 'the low Km ferricyanide reactive site' (Vinogradov, A.D., Gavrikova, E.V. and Goloveshkina, V.G. (1975) Biochem. Biophys, Res. Commun. 65, 1264--1269) is involved in reoxidation of the reduced enzyme by WB. 5. The pH dependence of V for the succinate-WB reductase reaction shows that the group of the enzyme with the pKa value of 6.7 at 22 degrees C is responsible for the reduction of dehydrogenase in the enzyme-substrate complex. 6. When WB interacts with the succinate-ubiquinone region of the respiratory chain, the double reciprocal plot 1/v versus 1/[WB] gives a straight line. The thenoyltrifluoroacetone inhibition of succinate-ubiquinone reductase or extraction of ubiquinone alter the 1/v versus 1/[WB] plots for the curves with a positive initial slope intercepting the ordinate at the same V as in the native particles. The data support the mechanism of succinate-ubiquinone reduction, in which no positive modulation of succinate dehydrogenase by ubiquinone exist in the membrane.
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Minamiura N, Yasunobu KT. Bovine liver monoamine oxidase. A modified purification procedure and preliminary evidence for two subunits and one FAD. Arch Biochem Biophys 1978; 189:481-9. [PMID: 708061 DOI: 10.1016/0003-9861(78)90237-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Voltti H, Hassinen IE. Oxidation-reduction midpoint potentials of mitochondrial flavoproteins and their intramitochondrial localization. J Bioenerg Biomembr 1978; 10:45-58. [PMID: 555461 DOI: 10.1007/bf00743226] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Spectrophotometric and fluorimetric substrate couple titrations and potentiometric spectrophotometric titrations were used to determine the oxidation-reduction potentials of components showing absorbance or fluorescence at the wavelengths attributable to the flavoproteins of mitochondria fractionated using digitonin together with sonication. A pure mitoplast fraction devoid of cytochrome b5 contamination could be obtained using 230 micrograms digitonin/mg of mitochondrial protein. The digitonin-soluble fraction contained a species having Em7.4 = -123 mV and probably represents the outer membrane flavoproteins. The inner membrane-matrix fraction, treated with ultrasound, provided evidence of a flavoprotein species with redox potential (Em7.4 = -302 mV) in the matrix fraction. The -302 mV component is probably lipoamide dehydrogenase. A high redox potential species with Em7.4 = +19 mV in titrations with the succinate fumarate couple was located in the inner membrane vesicles and is probably identical with succinate dehydrogenase. The electron-transferring flavoprotein (ETF) was isolated from bovine heart mitochondria and its Em7.4 = -74 mV determined. The component in the matrix fraction with an apparent Em7.4 = -56 mV probably represents ETF, and that in the inner membrane fraction with an apparent Em7.4 = -43 mV the NADH dehydrogenase flavoprotein. A component in an apparently low concentration with Em7.4 = +30 mV was detected in the inner membrane fraction. This probably represents the ETF-dehydrogenase flavoprotein. The origin of the flavoprotein fluorescence of mitochondria and intact tissues is discussed.
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Addison R, McCormick DB. Biogenesis of flavoprotein and cytochrome components in hepatic mitochondria from riboflavin-deficient rats. Biochem Biophys Res Commun 1978; 81:133-8. [PMID: 656090 DOI: 10.1016/0006-291x(78)91640-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Minamiura N, Yasunobu KT. Purification and some properties of porcine brain mitochondrial monoamine oxidase B. Biochem Pharmacol 1978; 27:2737-43. [PMID: 103556 DOI: 10.1016/0006-2952(78)90050-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Edmondson DE, Kenney WC, Singer TP. Synthesis and isolation of 8 alpha-substituted flavins and flavin peptides. Methods Enzymol 1978; 53:449-65. [PMID: 713850 DOI: 10.1016/s0076-6879(78)53049-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Muttart C, Chaudhuri R, Pinto J, Rivlin RS. Enhanced riboflavin incorporation into flavins in newborn riboflavin-deficient rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1977; 233:E397-401. [PMID: 920802 DOI: 10.1152/ajpendo.1977.233.5.e397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The incorporation of a subcutaneous injection of [14C]riboflavin (2.5 muCi/100 g body wt) into flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and flavins bound covalently to proteins was determined at 1, 6, and 18 h in liver, cerebrum, and cerebellum from progeny of normal and maternally riboflavin-deficient Holtzman rats. Radioactivity remaining as riboflavin was also determined under these circumstances. Experiments were initiated within 24 h of birth. In both groups of newborn rats, the incorporation of radioactive riboflavin into covalently bound flavins in liver and brain proceeded more slowly than into the other flavin fractions. In addition, radioactivity incorporated into covalently bound flavins comprised a relatively smaller proportion of the total amount incorporated in brain than in liver. In progeny of riboflavin-deficient dams, an increased rate of incorporation of riboflavin into all three flavin derivatives, particularly FAD, was observed in liver and brain, compared to results in normal progeny. These data provide evidence that maternal riboflavin deficiency enhances the incorporation of riboflavin into tissue flavins in liver, cerebrum, and cerebellum from newborn rats.
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Hemmerich P. The present status of flavin and flavocoenzyme chemistry. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE = PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS. PROGRES DANS LA CHIMIE DES SUBSTANCES ORGANIQUES NATURELLES 1976; 33:451-527. [PMID: 11156 DOI: 10.1007/978-3-7091-3262-3_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Pinto JT, Frisell WR. Characterization of the peptide-bound flavin of a bacterial sarcosine dehydrogenase. Arch Biochem Biophys 1975; 169:483-91. [PMID: 241294 DOI: 10.1016/0003-9861(75)90191-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Frisell WR, Randolph VM. N-methyl oxidation in liver mitochondria of triiodothyronine-treated and thyroidectomized rats. BIOCHIMICA ET BIOPHYSICA ACTA 1974; 347:145-50. [PMID: 4407317 DOI: 10.1016/0005-2728(74)90039-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hatefi Y, Hanstein WG, Davis KA, You KS. Structure of the mitochondrial electron transport system. Ann N Y Acad Sci 1974; 227:504-20. [PMID: 4151263 DOI: 10.1111/j.1749-6632.1974.tb14413.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Smith WG. The use of enzymology in pharmacological and toxicological investigations*. PROGRESS IN MEDICINAL CHEMISTRY 1974; 10:11-84. [PMID: 4617899 DOI: 10.1016/s0079-6468(08)70266-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Dombrowski JJ, Lambooy JP. The reduction of succinic dehydrogenase in the rat by 7-methyl-8-ethylflavin. Arch Biochem Biophys 1973; 159:378-82. [PMID: 4784464 DOI: 10.1016/0003-9861(73)90464-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Berezney R, Macaulay LK, Crane FL. The Purification and Biochemical Characterization of Bovine Liver Nuclear Membranes. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(20)81140-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Brühmüller M, Möhler H, Decker K. Covalently bound flavin in D-6-hydroxynicotine oxidase from Arthrobacter oxidans. Purification and properties of D-6-hydroxynicotine oxidase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 29:143-51. [PMID: 4628374 DOI: 10.1111/j.1432-1033.1972.tb01968.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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