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Curtolo F, Arantes GM. Dissecting Reaction Mechanisms and Catalytic Contributions in Flavoprotein Fumarate Reductases. J Chem Inf Model 2023. [PMID: 37196341 DOI: 10.1021/acs.jcim.3c00292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The interconversion between fumarate and succinate is fundamental to the energy metabolism of nearly all organisms. This redox reaction is catalyzed by a large family of enzymes, fumarate reductases and succinate dehydrogenases, using hydride and proton transfers from a flavin cofactor and a conserved Arg side-chain. These flavoenzymes also have substantial biomedical and biotechnological importance. Therefore, a detailed understanding of their catalytic mechanisms is valuable. Here, calibrated electronic structure calculations in a cluster model of the active site of the Fcc3 fumarate reductase were employed to investigate various reaction pathways and possible intermediates in the enzymatic environment and to dissect interactions that contribute to catalysis of fumarate reduction. Carbanion, covalent adduct, carbocation, and radical intermediates were examined. Significantly lower barriers were obtained for mechanisms via carbanion intermediates, with similar activation energies for hydride and proton transfers. Interestingly, the carbanion bound to the active site is best described as an enolate. Hydride transfer is stabilized by a preorganized charge dipole in the active site and by the restriction of the C1-C2 bond in a twisted conformation of the otherwise planar fumarate dianion. But, protonation of a fumarate carboxylate and quantum tunneling effects are not critical for catalysis of the hydride transfer. Calculations also suggest that the driving force for enzyme turnover is provided by regeneration of the catalytic Arg, either coupled with flavin reduction and decomposition of a proposed transient state or directly from the solvent. The detailed mechanistic description of enzymatic reduction of fumarate provided here clarifies previous contradictory views and provides new insights into catalysis by essential flavoenzyme reductases and dehydrogenases.
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Affiliation(s)
- Felipe Curtolo
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, São Paulo, Brazil
| | - Guilherme M Arantes
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, São Paulo, Brazil
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2
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Karavaeva V, Sousa FL. Modular structure of complex II: An evolutionary perspective. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148916. [PMID: 36084748 DOI: 10.1016/j.bbabio.2022.148916] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/21/2022] [Accepted: 09/02/2022] [Indexed: 11/25/2022]
Abstract
Succinate dehydrogenases (SDHs) and fumarate reductases (FRDs) catalyse the interconversion of succinate and fumarate, a reaction highly conserved in all domains of life. The current classification of SDH/FRDs is based on the structure of the membrane anchor subunits and their cofactors. It is, however, unknown whether this classification would hold in the context of evolution. In this work, a large-scale comparative genomic analysis of complex II addresses the questions of its taxonomic distribution and phylogeny. Our findings report that for types C, D, and F, structural classification and phylogeny go hand in hand, while for types A, B and E the situation is more complex, highlighting the possibility for their classification into subgroups. Based on these findings, we proposed a revised version of the evolutionary scenario for these enzymes in which a primordial soluble module, corresponding to the cytoplasmatic subunits, would give rise to the current diversity via several independent membrane anchor attachment events.
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Affiliation(s)
- Val Karavaeva
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030 Wien, Austria
| | - Filipa L Sousa
- Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.
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3
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Huang LS, Lümmen P, Berry EA. Crystallographic investigation of the ubiquinone binding site of respiratory Complex II and its inhibitors. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2021; 1869:140679. [PMID: 34089891 PMCID: PMC8516616 DOI: 10.1016/j.bbapap.2021.140679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/15/2021] [Accepted: 05/24/2021] [Indexed: 01/01/2023]
Abstract
The quinone binding site (Q-site) of Mitochondrial Complex II (succinate-ubiquinone oxidoreductase) is the target for a number of inhibitors useful for elucidating the mechanism of the enzyme. Some of these have been developed as fungicides or pesticides, and species-specific Q-site inhibitors may be useful against human pathogens. We report structures of chicken Complex II with six different Q-site inhibitors bound, at resolutions 2.0-2.4 Å. These structures show the common interactions between the inhibitors and their binding site. In every case a carbonyl or hydroxyl oxygen of the inhibitor is H-bonded to Tyr58 in subunit SdhD and Trp173 in subunit SdhB. Two of the inhibitors H-bond Ser39 in subunit SdhC directly, while two others do so via a water molecule. There is a distinct cavity that accepts the 2-substituent of the carboxylate ring in flutolanil and related inhibitors. A hydrophobic "tail pocket" opens to receive a side-chain of intermediate-length inhibitors. Shorter inhibitors fit entirely within the main binding cleft, while the long hydrophobic side chains of ferulenol and atpenin A5 protrude out of the cleft into the bulk lipid region, as presumably does that of ubiquinone. Comparison of mitochondrial and Escherichia coli Complex II shows a rotation of the membrane-anchor subunits by 7° relative to the iron‑sulfur protein. This rotation alters the geometry of the Q-site and the H-bonding pattern of SdhB:His216 and SdhD:Asp57. This conformational difference, rather than any active-site mutation, may be responsible for the different inhibitor sensitivity of the bacterial enzyme.
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Affiliation(s)
- Li-Shar Huang
- Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams Street, Syracuse, N.Y 13210, USA
| | - Peter Lümmen
- Bayer AG, Crop Science Division, Industrial Park Höchst, Frankfurt/Main, Germany
| | - Edward A Berry
- Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams Street, Syracuse, N.Y 13210, USA.
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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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5
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Sharma P, Maklashina E, Cecchini G, Iverson TM. Maturation of the respiratory complex II flavoprotein. Curr Opin Struct Biol 2019; 59:38-46. [PMID: 30851631 DOI: 10.1016/j.sbi.2019.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 12/13/2022]
Abstract
Respiratory complexes are complicated multi-subunit cofactor-containing machines that allow cells to harvest energy from the environment. Maturation of these complexes requires protein folding, cofactor insertion, and assembly of multiple subunits into a final, functional complex. Because the intermediate states in complex maturation are transitory, these processes are poorly understood. This review gives an overview of the process of maturation in respiratory complex II with a focus on recent structural studies on intermediates formed during covalent flavinylation of the catalytic subunit, SDHA. Covalent flavinylation has an evolutionary significance because variants of complex II enzymes with the covalent ligand removed by mutagenesis cannot oxidize succinate, but can still perform the reverse reaction and reduce fumarate. Since succinate oxidation is a key step of aerobic respiration, the covalent bond of complex II appears to be important for aerobic life.
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Affiliation(s)
- Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, United States.
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6
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Structure and electrochemistry of proteins harboring iron-sulfur clusters of different nuclearities. Part III. [4Fe-4S], [3Fe-4S] and [2Fe-2S] iron-sulfur proteins. J Struct Biol 2018; 202:264-274. [DOI: 10.1016/j.jsb.2018.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/16/2018] [Indexed: 11/18/2022]
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7
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Starbird C, Tomasiak TM, Singh PK, Yankovskaya V, Maklashina E, Eisenbach M, Cecchini G, Iverson T. New crystal forms of the integral membrane Escherichia coli quinol:fumarate reductase suggest that ligands control domain movement. J Struct Biol 2018; 202:100-104. [PMID: 29158068 PMCID: PMC5835405 DOI: 10.1016/j.jsb.2017.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/10/2017] [Accepted: 11/12/2017] [Indexed: 01/28/2023]
Abstract
Quinol:fumarate reductase (QFR) is an integral membrane protein and a member of the respiratory Complex II superfamily. Although the structure of Escherichia coli QFR was first reported almost twenty years ago, many open questions of catalysis remain. Here we report two new crystal forms of QFR, one grown from the lipidic cubic phase and one grown from dodecyl maltoside micelles. QFR crystals grown from the lipid cubic phase processed as P1, merged to 7.5 Å resolution, and exhibited crystal packing similar to previous crystal forms. Crystals grown from dodecyl maltoside micelles processed as P21, merged to 3.35 Å resolution, and displayed a unique crystal packing. This latter crystal form provides the first view of the E. coli QFR active site without a dicarboxylate ligand. Instead, an unidentified anion binds at a shifted position. In one of the molecules in the asymmetric unit, this is accompanied by rotation of the capping domain of the catalytic subunit. In the other molecule, this is associated with loss of interpretable electron density for this same capping domain. Analysis of the structure suggests that the ligand adjusts the position of the capping domain.
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Affiliation(s)
- C.A. Starbird
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Thomas M. Tomasiak
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Prashant K. Singh
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Victoria Yankovskaya
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, California 94121, Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, California 94121, Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158
| | - Michael Eisenbach
- Department of Biomolecular Sciences, Weizmann Institute of Science, Israel
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, California 94121, Department of Biochemistry & Biophysics, University of California, San Francisco, California 94158
| | - T.M. Iverson
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232,Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232
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8
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Sharma P, Maklashina E, Cecchini G, Iverson TM. Crystal structure of an assembly intermediate of respiratory Complex II. Nat Commun 2018; 9:274. [PMID: 29348404 PMCID: PMC5773532 DOI: 10.1038/s41467-017-02713-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/20/2017] [Indexed: 02/06/2023] Open
Abstract
Flavin is covalently attached to the protein scaffold in ~10% of flavoenzymes. However, the mechanism of covalent modification is unclear, due in part to challenges in stabilizing assembly intermediates. Here, we capture the structure of an assembly intermediate of the Escherichiacoli Complex II (quinol:fumarate reductase (FrdABCD)). The structure contains the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor, SdhE. The structure contains two global conformational changes as compared to prior structures of the mature protein: the rotation of a domain within the FrdA subunit, and the destabilization of two large loops of the FrdA subunit, which may create a tunnel to the active site. We infer a mechanism for covalent flavinylation. As supported by spectroscopic and kinetic analyses, we suggest that SdhE shifts the conformational equilibrium of the FrdA active site to disfavor succinate/fumarate interconversion and enhance covalent flavinylation. The mechanism for covalent flavinylation of flavoenzymes is still unclear. Here, the authors propose a mechanism based on the crystal structure of a flavinylation assembly intermediate of the E. coli respiratory Complex II comprising the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor SdhE.
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Affiliation(s)
- Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA, 94121, USA.,Department of Biochemistry & Biophysics, University of California, San Francisco, CA, 94158, USA
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA, 94121, USA. .,Department of Biochemistry & Biophysics, University of California, San Francisco, CA, 94158, USA.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA. .,Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA. .,Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA. .,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, 37232, USA.
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9
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Starbird CA, Maklashina E, Sharma P, Qualls-Histed S, Cecchini G, Iverson TM. Structural and biochemical analyses reveal insights into covalent flavinylation of the Escherichia coli Complex II homolog quinol:fumarate reductase. J Biol Chem 2017; 292:12921-12933. [PMID: 28615448 DOI: 10.1074/jbc.m117.795120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/07/2017] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli Complex II homolog quinol:fumarate reductase (QFR, FrdABCD) catalyzes the interconversion of fumarate and succinate at a covalently attached FAD within the FrdA subunit. The SdhE assembly factor enhances covalent flavinylation of Complex II homologs, but the mechanisms underlying the covalent attachment of FAD remain to be fully elucidated. Here, we explored the mechanisms of covalent flavinylation of the E. coli QFR FrdA subunit. Using a ΔsdhE E. coli strain, we show that the requirement for the assembly factor depends on the cellular redox environment. We next identified residues important for the covalent attachment and selected the FrdAE245 residue, which contributes to proton shuttling during fumarate reduction, for detailed biophysical and structural characterization. We found that QFR complexes containing FrdAE245Q have a structure similar to that of the WT flavoprotein, but lack detectable substrate binding and turnover. In the context of the isolated FrdA subunit, the anticipated assembly intermediate during covalent flavinylation, FrdAE245 variants had stability similar to that of WT FrdA, contained noncovalent FAD, and displayed a reduced capacity to interact with SdhE. However, small-angle X-ray scattering (SAXS) analysis of WT FrdA cross-linked to SdhE suggested that the FrdAE245 residue is unlikely to contribute directly to the FrdA-SdhE protein-protein interface. We also found that no auxiliary factor is absolutely required for flavinylation, indicating that the covalent flavinylation is autocatalytic. We propose that multiple factors, including the SdhE assembly factor and bound dicarboxylates, stimulate covalent flavinylation by preorganizing the active site to stabilize the quinone-methide intermediate.
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Affiliation(s)
- C A Starbird
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Elena Maklashina
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Susan Qualls-Histed
- Departments of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Gary Cecchini
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232.
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10
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Koenitzer JR, Bonacci G, Woodcock SR, Chen CS, Cantu-Medellin N, Kelley EE, Schopfer FJ. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II. Redox Biol 2015; 8:1-10. [PMID: 26722838 PMCID: PMC4710799 DOI: 10.1016/j.redox.2015.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/09/2015] [Indexed: 12/02/2022] Open
Abstract
Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the site of modification by OA-NO2 defined by mass spectrometric analysis. These effects translated into reduced basal and maximal respiration and favored glycolytic metabolism in H9C2 cardiomyoblasts as assessed by extracellular H+ and O2 flux analysis. The perfusion of NO2-FA induced acute cardioprotection in an isolated perfused heart ischemia/reperfusion (IR) model as evidenced by significantly higher rate-pressure products. Together these findings indicate that NO2-FA can promote cardioprotection by inducing a shift from respiration to glycolysis and suppressing reactive species formation in the post-ischemic interval. Nitro-oleic acid (OA-NO2) reversibly inhibits complex II-linked respiration. Nitrated fatty acid favor a switch from beta oxidation to glycolysis in cardiomyoblasts. Nitrated fatty acid induce cardioprotection in a heart ischemia/reperfusion model.
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Affiliation(s)
- Jeffrey R Koenitzer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Gustavo Bonacci
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Steven R Woodcock
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Chen-Shan Chen
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | | | - Eric E Kelley
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Francisco J Schopfer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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11
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Cheng VWT, Piragasam RS, Rothery RA, Maklashina E, Cecchini G, Weiner JH. Redox state of flavin adenine dinucleotide drives substrate binding and product release in Escherichia coli succinate dehydrogenase. Biochemistry 2015; 54:1043-52. [PMID: 25569225 DOI: 10.1021/bi501350j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Complex II family of enzymes, comprising respiratory succinate dehydrogenases and fumarate reductases, catalyzes reversible interconversion of succinate and fumarate. In contrast to the covalent flavin adenine dinucleotide (FAD) cofactor assembled in these enzymes, soluble fumarate reductases (e.g., those from Shewanella frigidimarina) that assemble a noncovalent FAD cannot catalyze succinate oxidation but retain the ability to reduce fumarate. In this study, an SdhA-H45A variant that eliminates the site of the 8α-N3-histidyl covalent linkage between the protein and FAD was examined. Variants SdhA-R286A/K/Y and -H242A/Y that target residues thought to be important for substrate binding and catalysis were also studied. The variants SdhA-H45A and -R286A/K/Y resulted in the assembly of a noncovalent FAD cofactor, which led to a significant decrease (-87 mV or more) in its reduction potential. The variant enzymes were studied by electron paramagnetic resonance spectroscopy following stand-alone reduction and potentiometric titrations. The "free" and "occupied" states of the active site were linked to the reduced and oxidized states of FAD, respectively. Our data allow for a proposed model of succinate oxidation that is consistent with tunnel diode effects observed in the succinate dehydrogenase enzyme and a preference for fumarate reduction catalysis in fumarate reductase homologues that assemble a noncovalent FAD.
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Affiliation(s)
- Victor W T Cheng
- Department of Biochemistry, University of Alberta , Edmonton, Alberta T6G 2H7, Canada
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12
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Zanello P. The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part II. {[Fe2S2](SγCys)4} proteins. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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Analysis of covalent flavinylation using thermostable succinate dehydrogenase from Thermus thermophilus and Sulfolobus tokodaii lacking SdhE homologs. FEBS Lett 2014; 588:1058-63. [PMID: 24566086 DOI: 10.1016/j.febslet.2014.02.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 11/20/2022]
Abstract
Recent studies have indicated that post-translational flavinylation of succinate dehydrogenase subunit A (SdhA) in eukaryotes and bacteria require the chaperone-like proteins Sdh5 and SdhE, respectively. How does covalent flavinylation occur in prokaryotes, which lack SdhE homologs? In this study, I showed that covalent flavinylation in two hyperthermophilic bacteria/archaea lacking SdhE, Thermus thermophilus and Sulfolobus tokodaii, requires heat and dicarboxylic acid. These thermophilic bacteria/archaea inhabit hot environments and are said to be genetically far removed from mesophilic bacteria which possess SdhE. Since mesophilic bacteria have been effective at covalent bonding in temperate environments, they may have caused the evolution of SdhE.
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14
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Singh PK, Sarwar M, Maklashina E, Kotlyar V, Rajagukguk S, Tomasiak TM, Cecchini G, Iverson TM. Plasticity of the quinone-binding site of the complex II homolog quinol:fumarate reductase. J Biol Chem 2013; 288:24293-301. [PMID: 23836905 DOI: 10.1074/jbc.m113.487082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Respiratory processes often use quinone oxidoreduction to generate a transmembrane proton gradient, making the 2H(+)/2e(-) quinone chemistry important for ATP synthesis. There are a variety of quinones used as electron carriers between bioenergetic proteins, and some respiratory proteins can functionally interact with more than one quinone type. In the case of complex II homologs, which couple quinone chemistry to the interconversion of succinate and fumarate, the redox potentials of the biologically available ubiquinone and menaquinone aid in driving the chemical reaction in one direction. In the complex II homolog quinol:fumarate reductase, it has been demonstrated that menaquinol oxidation requires at least one proton shuttle, but many of the remaining mechanistic details of menaquinol oxidation are not fully understood, and little is known about ubiquinone reduction. In the current study, structural and computational studies suggest that the sequential removal of the two menaquinol protons may be accompanied by a rotation of the naphthoquinone ring to optimize the interaction with a second proton shuttling pathway. However, kinetic measurements of site-specific mutations of quinol:fumarate reductase variants show that ubiquinone reduction does not use the same pathway. Computational docking of ubiquinone followed by mutagenesis instead suggested redundant proton shuttles lining the ubiquinone-binding site or from direct transfer from solvent. These data show that the quinone-binding site provides an environment that allows multiple amino acid residues to participate in quinone oxidoreduction. This suggests that the quinone-binding site in complex II is inherently plastic and can robustly interact with different types of quinones.
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Affiliation(s)
- Prashant K Singh
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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15
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Harada S, Inaoka DK, Ohmori J, Kita K. Diversity of parasite complex II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:658-67. [PMID: 23333273 DOI: 10.1016/j.bbabio.2013.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/07/2013] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
Abstract
Parasites have developed a variety of physiological functions necessary for completing at least part of their life cycles in the specialized environments of surrounding the parasites in the host. Regarding energy metabolism, which is essential for survival, parasites adapt to the low oxygen environment in mammalian hosts by using metabolic systems that are very different from those of the hosts. In many cases, the parasite employs aerobic metabolism during the free-living stage outside the host but undergoes major changes in developmental control and environmental adaptation to switch to anaerobic energy metabolism. Parasite mitochondria play diverse roles in their energy metabolism, and in recent studies of the parasitic nematode, Ascaris suum, the mitochondrial complex II plays an important role in anaerobic energy metabolism of parasites inhabiting hosts by acting as a quinol-fumarate reductase. In Trypanosomes, parasite complex II has been found to have a novel function and structure. Complex II of Trypanosoma cruzi is an unusual supramolecular complex with a heterodimeric iron-sulfur subunit and seven additional non-catalytic subunits. The enzyme shows reduced binding affinities for both substrates and inhibitors. Interestingly, this structural organization is conserved in all trypanosomatids. Since the properties of complex II differ across a wide range of parasites, this complex is a potential target for the development of new chemotherapeutic agents. In this regard, structural information on the target enzyme is essential for the molecular design of drugs. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- Shigeharu Harada
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan.
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Iverson TM. Catalytic mechanisms of complex II enzymes: a structural perspective. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:648-57. [PMID: 22995215 DOI: 10.1016/j.bbabio.2012.09.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/07/2012] [Accepted: 09/10/2012] [Indexed: 11/25/2022]
Abstract
Over a decade has passed since the elucidation of the first X-ray crystal structure of any complex II homolog. In the intervening time, the structures of five additional integral-membrane complex II enzymes and three homologs of the soluble domain have been determined. These structures have provided a framework for the analysis of enzymological studies of complex II superfamily enzymes, and have contributed to detailed proposals for reaction mechanisms at each of the two enzyme active sites, which catalyze dicarboxylate and quinone oxidoreduction, respectively. This review focuses on how structural data have augmented our understanding of catalysis by the superfamily. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- T M Iverson
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232-6600, USA.
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Iverson TM, Maklashina E, Cecchini G. Structural basis for malfunction in complex II. J Biol Chem 2012; 287:35430-35438. [PMID: 22904323 DOI: 10.1074/jbc.r112.408419] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Complex II couples oxidoreduction of succinate and fumarate at one active site with that of quinol/quinone at a second distinct active site over 40 Å away. This process links the Krebs cycle to oxidative phosphorylation and ATP synthesis. The pathogenic mutation or inhibition of human complex II or its assembly factors is often associated with neurodegeneration or tumor formation in tissues derived from the neural crest. This brief overview of complex II correlates the clinical presentations of a large number of symptom-associated alterations in human complex II activity and assembly with the biochemical manifestations of similar alterations in the complex II homologs from Escherichia coli. These analyses provide clues to the molecular basis for diseases associated with aberrant complex II function.
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Affiliation(s)
- Tina M Iverson
- Department of Pharmacology and Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee 37232.
| | - Elena Maklashina
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Gary Cecchini
- Molecular Biology Division, Veterans Affairs Medical Center, San Francisco, California 94121; Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158.
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Shimizu H, Osanai A, Sakamoto K, Inaoka DK, Shiba T, Harada S, Kita K. Crystal structure of mitochondrial quinol-fumarate reductase from the parasitic nematode Ascaris suum. J Biochem 2012; 151:589-92. [DOI: 10.1093/jb/mvs051] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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