1
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Duffus BR, Gauglitz M, Teutloff C, Leimkühler S. Redox potentials elucidate the electron transfer pathway of NAD +-dependent formate dehydrogenases. J Inorg Biochem 2024; 253:112487. [PMID: 38306887 DOI: 10.1016/j.jinorgbio.2024.112487] [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: 10/24/2023] [Revised: 01/16/2024] [Accepted: 01/16/2024] [Indexed: 02/04/2024]
Abstract
Metal-dependent, nicotine adenine dinucleotide (NAD+)-dependent formate dehydrogenases (FDHs) are complex metalloenzymes coupling biochemical transformations through intricate electron transfer pathways. Rhodobacter capsulatus FDH is a model enzyme for understanding coupled catalysis, in that reversible CO2 reduction and formate oxidation are linked to a flavin mononuclotide (FMN)-bound diaphorase module via seven iron-sulfur (FeS) clusters as a dimer of heterotetramers. Catalysis occurs at a bis-metal-binding pterin (Mo) binding two molybdopterin guanine dinucleotides (bis-MGD), a protein-based Cys residue and a participatory sulfido ligand. Insights regarding the proposed electron transfer mechanism between the bis-MGD and the FMN have been complicated by the discovery that an alternative pathway might occur via intersubunit electron transfer between two [4Fe4S] clusters within electron transfer distance. To clarify this difference, the redox potentials of the bis-MGD and the FeS clusters were determined via redox titration by EPR spectroscopy. Redox potentials for the bis-MGD cofactor and five of the seven FeS clusters could be assigned. Furthermore, substitution of the active site residue Lys295 with Ala resulted in altered enzyme kinetics, primarily due to a more negative redox potential of the A1 [4Fe4S] cluster. Finally, characterization of the monomeric FdsGBAD heterotetramer exhibited slightly decreased formate oxidation activity and similar iron-sulfur clusters reduced relative to the dimeric heterotetramer. Comparison of the measured redox potentials relative to structurally defined FeS clusters support a mechanism by which electron transfer occurs within a heterotetrameric unit, with the interfacial [4Fe4S] cluster serving as a structural component toward the integrity of the heterodimeric structure to drive efficient catalysis.
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Affiliation(s)
- Benjamin R Duffus
- Institute for Biochemistry and Biology, Molecular Enzymology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - Marcel Gauglitz
- Institute for Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Christian Teutloff
- Institute for Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Silke Leimkühler
- Institute for Biochemistry and Biology, Molecular Enzymology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
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2
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Harmer JR, Hakopian S, Niks D, Hille R, Bernhardt PV. Redox Characterization of the Complex Molybdenum Enzyme Formate Dehydrogenase from Cupriavidus necator. J Am Chem Soc 2023; 145:25850-25863. [PMID: 37967365 DOI: 10.1021/jacs.3c10199] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
The oxygen-tolerant and molybdenum-dependent formate dehydrogenase FdsDABG from Cupriavidus necator is capable of catalyzing both formate oxidation to CO2 and the reverse reaction (CO2 reduction to formate) at neutral pH, which are both reactions of great importance to energy production and carbon capture. FdsDABG is replete with redox cofactors comprising seven Fe/S clusters, flavin mononucleotide, and a molybdenum ion coordinated by two pyranopterin dithiolene ligands. The redox potentials of these centers are described herein and assigned to specific cofactors using combinations of potential-dependent continuous wave and pulse EPR spectroscopy and UV/visible spectroelectrochemistry on both the FdsDABG holoenzyme and the FdsBG subcomplex. These data represent the first redox characterization of a complex metal dependent formate dehydrogenase and provide an understanding of the highly efficient catalytic formate oxidation and CO2 reduction activity that are associated with the enzyme.
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Affiliation(s)
- Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Sheron Hakopian
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Dimitri Niks
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Russ Hille
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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3
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Insertion of CO 2 in metal ion-doped two-dimensional covalent organic frameworks. Proc Natl Acad Sci U S A 2023; 120:e2217081120. [PMID: 36812199 PMCID: PMC9992840 DOI: 10.1073/pnas.2217081120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Carbon capture is one of the essential low-carbon technologies required to achieve societal climate goals at the lowest cost. Covalent organic frameworks (COFs) are promising adsorbents for CO2 capture because of their well-defined porosity, large surface area, and high stability. Current COF-based CO2 capture is mainly based on a physisorption mechanism, exhibiting smooth and reversible sorption isotherms. In the present study, we report unusual CO2 sorption isotherms featuring one or more tunable hysteresis steps with metal ion (Fe3+, Cr3+, or In3+)-doped Schiff-base two-dimensional (2D) COFs (Py-1P, Py-TT, and Py-Py) as adsorbents. Synchrotron X-ray diffraction, spectroscopic and computational studies indicate that the sharp adsorption steps in the isotherm originate from the insertion of CO2 between the metal ion and the N atom of the imine bond on the inner pore surface of the COFs as the CO2 pressure reaches threshold values. As a result, the CO2 adsorption capacity of the ion-doped Py-1P COF is increased by 89.5% compared with that of the undoped Py-1P COF. This CO2 sorption mechanism provides an efficient and straightforward approach to enhancing the CO2 capture capacity of COF-based adsorbents, yielding insights into developing chemistry for CO2 capture and conversion.
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4
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Velours C, Zhou J, Zecchin P, He N, Salameh M, Golinelli-Cohen MP, Golinelli-Pimpaneau B. Determination of the Absolute Molar Mass of [Fe-S]-Containing Proteins Using Size Exclusion Chromatography-Multi-Angle Light Scattering (SEC-MALS). Biomolecules 2022; 12:biom12020270. [PMID: 35204772 PMCID: PMC8961635 DOI: 10.3390/biom12020270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/25/2022] [Accepted: 02/03/2022] [Indexed: 12/12/2022] Open
Abstract
Size Exclusion Chromatography coupled with Multi-Angle Light Scattering (SEC-MALS) is a technique that determines the absolute molar mass (molecular weight) of macromolecules in solution, such as proteins or polymers, by detecting their light scattering intensity. Because SEC-MALS does not rely on the assumption of the globular state of the analyte and the calibration of standards, the molar mass can be obtained for proteins of any shape, as well as for intrinsically disordered proteins and aggregates. Yet, corrections need to be made for samples that absorb light at the wavelength of the MALS laser, such as iron–sulfur [Fe-S] cluster-containing proteins. We analyze several examples of [2Fe-2S] and [4Fe-4S] cluster-containing proteins, for which various corrections were applied to determine the absolute molar mass of both the apo- and holo-forms. Importantly, the determination of the absolute molar mass of the [2Fe-2S]-containing holo-NEET proteins allowed us to ascertain a change in the oligomerization state upon cluster binding and, thus, to highlight one essential function of the cluster.
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Affiliation(s)
- Christophe Velours
- Fundamental Microbiology and Pathogenicity Laboratory, UMR 5234 CNRS-University of Bordeaux, SFR TransBioMed, 33076 Bordeaux, France
- Institute for Integrative Biology of the Cell (I2BC), CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
- Correspondence: (C.V.); (B.G.-P.)
| | - Jingjing Zhou
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Sorbonne Université, 11 Place Marcelin Berthelot, 75231 Paris, France; (J.Z.); (P.Z.); (N.H.)
| | - Paolo Zecchin
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Sorbonne Université, 11 Place Marcelin Berthelot, 75231 Paris, France; (J.Z.); (P.Z.); (N.H.)
| | - Nisha He
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Sorbonne Université, 11 Place Marcelin Berthelot, 75231 Paris, France; (J.Z.); (P.Z.); (N.H.)
| | - Myriam Salameh
- Institut de Chimie des Substances Naturelles, Université Paris-Saclay, CNRS, UPR2301, 91198 Gif-sur-Yvette, France; (M.S.); (M.-P.G.-C.)
| | - Marie-Pierre Golinelli-Cohen
- Institut de Chimie des Substances Naturelles, Université Paris-Saclay, CNRS, UPR2301, 91198 Gif-sur-Yvette, France; (M.S.); (M.-P.G.-C.)
| | - Béatrice Golinelli-Pimpaneau
- Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Sorbonne Université, 11 Place Marcelin Berthelot, 75231 Paris, France; (J.Z.); (P.Z.); (N.H.)
- Correspondence: (C.V.); (B.G.-P.)
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5
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Richardson KH, Wright JJ, Šimėnas M, Thiemann J, Esteves AM, McGuire G, Myers WK, Morton JJL, Hippler M, Nowaczyk MM, Hanke GT, Roessler MM. Functional basis of electron transport within photosynthetic complex I. Nat Commun 2021; 12:5387. [PMID: 34508071 PMCID: PMC8433477 DOI: 10.1038/s41467-021-25527-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/11/2021] [Indexed: 02/08/2023] Open
Abstract
Photosynthesis and respiration rely upon a proton gradient to produce ATP. In photosynthesis, the Respiratory Complex I homologue, Photosynthetic Complex I (PS-CI) is proposed to couple ferredoxin oxidation and plastoquinone reduction to proton pumping across thylakoid membranes. However, little is known about the PS-CI molecular mechanism and attempts to understand its function have previously been frustrated by its large size and high lability. Here, we overcome these challenges by pushing the limits in sample size and spectroscopic sensitivity, to determine arguably the most important property of any electron transport enzyme - the reduction potentials of its cofactors, in this case the iron-sulphur clusters of PS-CI (N0, N1 and N2), and unambiguously assign them to the structure using double electron-electron resonance. We have thus determined the bioenergetics of the electron transfer relay and provide insight into the mechanism of PS-CI, laying the foundations for understanding of how this important bioenergetic complex functions.
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Affiliation(s)
- Katherine H. Richardson
- grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK ,grid.7445.20000 0001 2113 8111Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - John J. Wright
- grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK ,grid.14105.310000000122478951Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge, UK
| | - Mantas Šimėnas
- grid.83440.3b0000000121901201London Centre for Nanotechnology, University College London, London, UK
| | - Jacqueline Thiemann
- grid.5570.70000 0004 0490 981XPlant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Ana M. Esteves
- grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Gemma McGuire
- grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK ,grid.7445.20000 0001 2113 8111Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - William K. Myers
- grid.4991.50000 0004 1936 8948Inorganic Chemistry, University of Oxford, Oxford, UK
| | - John J. L. Morton
- grid.83440.3b0000000121901201London Centre for Nanotechnology, University College London, London, UK ,grid.83440.3b0000000121901201Department of Electronic & Electrical Engineering, UCL, London, UK
| | - Michael Hippler
- grid.5949.10000 0001 2172 9288Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany ,grid.261356.50000 0001 1302 4472Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Marc M. Nowaczyk
- grid.5570.70000 0004 0490 981XPlant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Guy T. Hanke
- grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Maxie M. Roessler
- grid.7445.20000 0001 2113 8111Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
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6
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Stich TA. Characterization of Paramagnetic Iron-Sulfur Clusters Using Electron Paramagnetic Resonance Spectroscopy. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2353:259-280. [PMID: 34292554 DOI: 10.1007/978-1-0716-1605-5_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Continuous-wave (CW) electron paramagnetic resonance (EPR) spectroscopy is a powerful ally in characterizing the multitude of redox-active iron-sulfur cluster-containing ([Fe-S]) species present in biological samples. The technique detects only those clusters that are paramagnetic-having a nonzero total electron spin (S > 0)-thus, it can discriminate between clusters in different oxidation states. The low-temperature CW-EPR spectrum of an [Fe-S] yields the three magnetic g-values that serve as a fingerprint of its electronic structure. This chapter briefly describes the underlying theory that defines this electronic structure and provides a recipe for the acquisition and analysis of EPR spectra of [Fe-S] proteins.
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Affiliation(s)
- Troy A Stich
- Department of Chemistry, Wake Forest University, Winston-Salem, NC, USA.
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7
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Melin F, Hellwig P. Redox Properties of the Membrane Proteins from the Respiratory Chain. Chem Rev 2020; 120:10244-10297. [DOI: 10.1021/acs.chemrev.0c00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Frederic Melin
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
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8
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Schulte M, Frick K, Gnandt E, Jurkovic S, Burschel S, Labatzke R, Aierstock K, Fiegen D, Wohlwend D, Gerhardt S, Einsle O, Friedrich T. A mechanism to prevent production of reactive oxygen species by Escherichia coli respiratory complex I. Nat Commun 2019; 10:2551. [PMID: 31186428 PMCID: PMC6560083 DOI: 10.1038/s41467-019-10429-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 05/08/2019] [Indexed: 11/21/2022] Open
Abstract
Respiratory complex I plays a central role in cellular energy metabolism coupling NADH oxidation to proton translocation. In humans its dysfunction is associated with degenerative diseases. Here we report the structure of the electron input part of Aquifex aeolicus complex I at up to 1.8 Å resolution with bound substrates in the reduced and oxidized states. The redox states differ by the flip of a peptide bond close to the NADH binding site. The orientation of this peptide bond is determined by the reduction state of the nearby [Fe-S] cluster N1a. Fixation of the peptide bond by site-directed mutagenesis led to an inactivation of electron transfer and a decreased reactive oxygen species (ROS) production. We suggest the redox-gated peptide flip to represent a previously unrecognized molecular switch synchronizing NADH oxidation in response to the redox state of the complex as part of an intramolecular feed-back mechanism to prevent ROS production. Respiratory complex I plays a central role in cellular energy metabolism coupling NADH oxidation to proton translocation. Here, the authors report the structure of the electron input part of Aquifex aeolicus complex I at up to 1.8 Å resolution with bound substrates in the reduced and oxidized states.
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Affiliation(s)
- Marius Schulte
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Klaudia Frick
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Emmanuel Gnandt
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Sascha Jurkovic
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Sabrina Burschel
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Ramona Labatzke
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Karoline Aierstock
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany.,Boehringer Ingelheim Pharma GmbH & Co. KG, Lead Identification and Optimization Sup, 88397, Biberach, Germany
| | - Dennis Fiegen
- Boehringer Ingelheim Pharma GmbH & Co. KG, Lead Identification and Optimization Sup, 88397, Biberach, Germany
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Stefan Gerhardt
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany.
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9
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Schuller JM, Birrell JA, Tanaka H, Konuma T, Wulfhorst H, Cox N, Schuller SK, Thiemann J, Lubitz W, Sétif P, Ikegami T, Engel BD, Kurisu G, Nowaczyk MM. Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer. Science 2018; 363:257-260. [PMID: 30573545 DOI: 10.1126/science.aau3613] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/06/2018] [Indexed: 12/22/2022]
Abstract
Photosynthetic complex I enables cyclic electron flow around photosystem I, a regulatory mechanism for photosynthetic energy conversion. We report a 3.3-angstrom-resolution cryo-electron microscopy structure of photosynthetic complex I from the cyanobacterium Thermosynechococcus elongatus. The model reveals structural adaptations that facilitate binding and electron transfer from the photosynthetic electron carrier ferredoxin. By mimicking cyclic electron flow with isolated components in vitro, we demonstrate that ferredoxin directly mediates electron transfer between photosystem I and complex I, instead of using intermediates such as NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). A large rate constant for association of ferredoxin to complex I indicates efficient recognition, with the protein subunit NdhS being the key component in this process.
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Affiliation(s)
- Jan M Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Hideaki Tanaka
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.,Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Tsuyoshi Konuma
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Hannes Wulfhorst
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.,Daiichi Sankyo Deutschland GmbH, Zielstattstr. 48, 81379 München, Germany
| | - Nicholas Cox
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany.,Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Sandra K Schuller
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Jacqueline Thiemann
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany
| | - Pierre Sétif
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Université Paris-Saclay, F-91198 Gif-sur-Yvette, France
| | - Takahisa Ikegami
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan. .,Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.
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10
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Burschel S, Kreuzer Decovic D, Nuber F, Stiller M, Hofmann M, Zupok A, Siemiatkowska B, Gorka M, Leimkühler S, Friedrich T. Iron-sulfur cluster carrier proteins involved in the assembly of Escherichia coli
NADH:ubiquinone oxidoreductase (complex I). Mol Microbiol 2018; 111:31-45. [DOI: 10.1111/mmi.14137] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 09/10/2018] [Accepted: 09/19/2018] [Indexed: 01/26/2023]
Affiliation(s)
- Sabrina Burschel
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
| | - Doris Kreuzer Decovic
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
- Spemann Graduate School of Biology and Medicine (SGBM); University of Freiburg; Germany
| | - Franziska Nuber
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
| | - Marie Stiller
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
| | - Maud Hofmann
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
| | - Arkadiusz Zupok
- University of Potsdam; Institut für Biochemie und Biologie; Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
| | - Beata Siemiatkowska
- Max-Planck-Institute of Molecular Plant Physiology; Am Mühlenberg 1 14476 Potsdam-Golm Germany
| | - Michal Gorka
- Max-Planck-Institute of Molecular Plant Physiology; Am Mühlenberg 1 14476 Potsdam-Golm Germany
| | - Silke Leimkühler
- University of Potsdam; Institut für Biochemie und Biologie; Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
| | - Thorsten Friedrich
- Albert-Ludwigs-Universität, Institut für Biochemie; Albertstr. 21 D-79104 Freiburg Germany
- Spemann Graduate School of Biology and Medicine (SGBM); University of Freiburg; Germany
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11
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Kalyanaraman B, Cheng G, Zielonka J, Bennett B. Low-Temperature EPR Spectroscopy as a Probe-Free Technique for Monitoring Oxidants Formed in Tumor Cells and Tissues: Implications in Drug Resistance and OXPHOS-Targeted Therapies. Cell Biochem Biophys 2018; 77:89-98. [PMID: 30259334 DOI: 10.1007/s12013-018-0858-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/12/2018] [Indexed: 12/12/2022]
Abstract
Oxidants formed from oxidative and nitrative metabolism include reactive oxygen species (ROS) such as superoxide, hydrogen peroxide/lipid hydroperoxides and reactive nitrogen species (RNS) (e.g., peroxynitrite [ONOO-] and nitrogen dioxide), and reactive halogenated species (e.g., hypochlorous acid [HOCl]). Increasingly, ROS and RNS are implicated in tumorigenesis as well as tumor growth, progression, and metastasis. Recently, ROS were implicated in drug resistance, metabolic reprogramming, and T-cell metabolism in immunotherapy. Mostly, fluorescent probes have been used in cell culture systems. The identity of species is obtained by LC-MS analyses of diagnostic marker products. However, extrapolation of these assays to cancer xenografts is difficult if not impossible. Thus, development of a probe-free assay for monitoring and assessing oxidant formation in tumor cells and tumor xenografts is critical and timely. Here, we describe the use of ex vivo electron paramagnetic resonance (EPR) spectroscopy at cryogenic temperatures as a uniquely useful probe-free technique for assessing intracellular oxidation and oxidants via EPR signals from redox centers, particularly iron-sulfur clusters, in mitochondrial and cytosolic redox proteins. Examples of cancer cells subjected to inhibition of mitochondrial oxidative phosphorylation are presented. This ex vivo methodology can be readily extended to monitor oxidant formation in tumor tissues isolated from mice and humans.
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Affiliation(s)
- Balaraman Kalyanaraman
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA. .,Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA. .,Cancer Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
| | - Gang Cheng
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Jacek Zielonka
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Cancer Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Brian Bennett
- Department of Physics, Marquette University, 540 N. 15th St., Milwaukee, WI, 53233, USA.
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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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13
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Langley M, Ghosh A, Charli A, Sarkar S, Ay M, Luo J, Zielonka J, Brenza T, Bennett B, Jin H, Ghaisas S, Schlichtmann B, Kim D, Anantharam V, Kanthasamy A, Narasimhan B, Kalyanaraman B, Kanthasamy AG. Mito-Apocynin Prevents Mitochondrial Dysfunction, Microglial Activation, Oxidative Damage, and Progressive Neurodegeneration in MitoPark Transgenic Mice. Antioxid Redox Signal 2017; 27:1048-1066. [PMID: 28375739 PMCID: PMC5651937 DOI: 10.1089/ars.2016.6905] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AIMS Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive motor deficits and degeneration of dopaminergic neurons. Caused by a number of genetic and environmental factors, mitochondrial dysfunction and oxidative stress play a role in neurodegeneration in PD. By selectively knocking out mitochondrial transcription factor A (TFAM) in dopaminergic neurons, the transgenic MitoPark mice recapitulate many signature features of the disease, including progressive motor deficits, neuronal loss, and protein inclusions. In the present study, we evaluated the neuroprotective efficacy of a novel mitochondrially targeted antioxidant, Mito-apocynin, in MitoPark mice and cell culture models of neuroinflammation and mitochondrial dysfunction. RESULTS Oral administration of Mito-apocynin (10 mg/kg, thrice a week) showed excellent central nervous system bioavailability and significantly improved locomotor activity and coordination in MitoPark mice. Importantly, Mito-apocynin also partially attenuated severe nigrostriatal degeneration in MitoPark mice. Mechanistic studies revealed that Mito-apo improves mitochondrial function and inhibits NOX2 activation, oxidative damage, and neuroinflammation. INNOVATION The properties of Mito-apocynin identified in the MitoPark transgenic mouse model strongly support potential clinical applications for Mito-apocynin as a viable neuroprotective and anti-neuroinflammatory drug for treating PD when compared to conventional therapeutic approaches. CONCLUSION Collectively, our data demonstrate, for the first time, that a novel orally active apocynin derivative improves behavioral, inflammatory, and neurodegenerative processes in a severe progressive dopaminergic neurodegenerative model of PD. Antioxid. Redox Signal. 27, 1048-1066.
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Affiliation(s)
- Monica Langley
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Anamitra Ghosh
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Adhithiya Charli
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Souvarish Sarkar
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Muhammet Ay
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Jie Luo
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Jacek Zielonka
- 2 Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Timothy Brenza
- 3 Department of Chemical and Biological Engineering, Iowa State University , Ames, Iowa
| | - Brian Bennett
- 4 Department of Physics, Marquette University , Milwaukee, Wisconsin
| | - Huajun Jin
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Shivani Ghaisas
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Benjamin Schlichtmann
- 3 Department of Chemical and Biological Engineering, Iowa State University , Ames, Iowa
| | - Dongsuk Kim
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Vellareddy Anantharam
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Arthi Kanthasamy
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
| | - Balaji Narasimhan
- 3 Department of Chemical and Biological Engineering, Iowa State University , Ames, Iowa
| | | | - Anumantha G Kanthasamy
- 1 Department of Biomedical Sciences, Iowa Center for Advanced Neurotoxicology, Iowa State University , Ames, Iowa
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Le Breton N, Wright JJ, Jones AJY, Salvadori E, Bridges HR, Hirst J, Roessler MM. Using Hyperfine Electron Paramagnetic Resonance Spectroscopy to Define the Proton-Coupled Electron Transfer Reaction at Fe-S Cluster N2 in Respiratory Complex I. J Am Chem Soc 2017; 139:16319-16326. [PMID: 29039928 DOI: 10.1021/jacs.7b09261] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Energy-transducing respiratory complex I (NADH:ubiquinone oxidoreductase) is one of the largest and most complicated enzymes in mammalian cells. Here, we used hyperfine electron paramagnetic resonance (EPR) spectroscopic methods, combined with site-directed mutagenesis, to determine the mechanism of a single proton-coupled electron transfer reaction at one of eight iron-sulfur clusters in complex I, [4Fe-4S] cluster N2. N2 is the terminal cluster of the enzyme's intramolecular electron-transfer chain and the electron donor to ubiquinone. Because of its position and pH-dependent reduction potential, N2 has long been considered a candidate for the elusive "energy-coupling" site in complex I at which energy generated by the redox reaction is used to initiate proton translocation. Here, we used hyperfine sublevel correlation (HYSCORE) spectroscopy, including relaxation-filtered hyperfine and single-matched resonance transfer (SMART) HYSCORE, to detect two weakly coupled exchangeable protons near N2. We assign the larger coupling with A(1H) = [-3.0, -3.0, 8.7] MHz to the exchangeable proton of a conserved histidine and conclude that the histidine is hydrogen-bonded to N2, tuning its reduction potential. The histidine protonation state responds to the cluster oxidation state, but the two are not coupled sufficiently strongly to catalyze a stoichiometric and efficient energy transduction reaction. We thus exclude cluster N2, despite its proton-coupled electron transfer chemistry, as the energy-coupling site in complex I. Our work demonstrates the capability of pulse EPR methods for providing detailed information on the properties of individual protons in even the most challenging of energy-converting enzymes.
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Affiliation(s)
- Nolwenn Le Breton
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
| | - John J Wright
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
| | - Andrew J Y Jones
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Enrico Salvadori
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom.,London Centre for Nanotechnology, University College London , 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Maxie M Roessler
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
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15
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Structure and electrochemistry of proteins harboring iron-sulfur clusters of different nuclearities. Part I. [4Fe-4S] + [2Fe-2S] iron-sulfur proteins. J Struct Biol 2017; 200:1-19. [DOI: 10.1016/j.jsb.2017.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/25/2017] [Indexed: 01/08/2023]
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16
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Artz JH, Mulder DW, Ratzloff MW, Lubner CE, Zadvornyy OA, LeVan AX, Williams SG, Adams MWW, Jones AK, King PW, Peters JW. Reduction Potentials of [FeFe]-Hydrogenase Accessory Iron-Sulfur Clusters Provide Insights into the Energetics of Proton Reduction Catalysis. J Am Chem Soc 2017. [PMID: 28635269 DOI: 10.1021/jacs.7b02099] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
An [FeFe]-hydrogenase from Clostridium pasteurianum, CpI, is a model system for biological H2 activation. In addition to the catalytic H-cluster, CpI contains four accessory iron-sulfur [FeS] clusters in a branched series that transfer electrons to and from the active site. In this work, potentiometric titrations have been employed in combination with electron paramagnetic resonance (EPR) spectroscopy at defined electrochemical potentials to gain insights into the role of the accessory clusters in catalysis. EPR spectra collected over a range of potentials were deconvoluted into individual components attributable to the accessory [FeS] clusters and the active site H-cluster, and reduction potentials for each cluster were determined. The data suggest a large degree of magnetic coupling between the clusters. The distal [4Fe-4S] cluster is shown to have a lower reduction potential (∼ < -450 mV) than the other clusters, and molecular docking experiments indicate that the physiological electron donor, ferredoxin (Fd), most favorably interacts with this cluster. The low reduction potential of the distal [4Fe-4S] cluster thermodynamically restricts the Fdox/Fdred ratio at which CpI can operate, consistent with the role of CpI in recycling Fdred that accumulates during fermentation. Subsequent electron transfer through the additional accessory [FeS] clusters to the H-cluster is thermodynamically favorable.
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Affiliation(s)
- Jacob H Artz
- Institute of Biological Chemistry, Washington State University , 258 Clark Hall, Pullman, Washington 99163, United States
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Michael W Ratzloff
- Biosciences Center, National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Carolyn E Lubner
- Biosciences Center, National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Oleg A Zadvornyy
- Institute of Biological Chemistry, Washington State University , 258 Clark Hall, Pullman, Washington 99163, United States
| | - Axl X LeVan
- Department of Chemistry and Biochemistry, Montana State University , 224 Chemistry and Biochemistry Building, Bozeman, Montana 59717, United States
| | - S Garrett Williams
- School of Molecular Sciences, Arizona State University , P.O. Box 871604, Tempe, Arizona 85287, United States
| | - Michael W W Adams
- B216B Life Sciences Complex, Department of Biochemistry, The University of Georgia , Athens, Georgia 30602, United States
| | - Anne K Jones
- School of Molecular Sciences, Arizona State University , P.O. Box 871604, Tempe, Arizona 85287, United States
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory , 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - John W Peters
- Institute of Biological Chemistry, Washington State University , 258 Clark Hall, Pullman, Washington 99163, United States
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17
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Wright JJ, Salvadori E, Bridges HR, Hirst J, Roessler MM. Small-volume potentiometric titrations: EPR investigations of Fe-S cluster N2 in mitochondrial complex I. J Inorg Biochem 2016; 162:201-206. [DOI: 10.1016/j.jinorgbio.2016.04.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
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18
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Gnandt E, Dörner K, Strampraad MFJ, de Vries S, Friedrich T. The multitude of iron-sulfur clusters in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1068-1072. [PMID: 26944855 DOI: 10.1016/j.bbabio.2016.02.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/19/2016] [Accepted: 02/26/2016] [Indexed: 12/13/2022]
Abstract
Respiratory complex I couples the electron transfer from NADH to ubiquinone with the translocation of protons across the membrane. Complex I contains one non-covalently bound flavin mononucleotide and, depending on the species, up to ten iron-sulfur (Fe/S) clusters as cofactors. The reason for the presence of the multitude of Fe/S clusters in complex I remained enigmatic for a long time. The question was partly answered by investigations on the evolution of the complex revealing the stepwise construction of the electron transfer domain from several modules. Extension of the ancestral to the modern electron input domain was associated with the acquisition of several Fe/S-proteins. The X-ray structure of the complex showed that the NADH oxidation-site is connected with the quinone-reduction site by a chain of seven Fe/S-clusters. Fast enzyme kinetics revealed that this chain of Fe/S-clusters is used to regulate electron-tunneling rates within the complex. A possible function of the off-pathway cluster N1a is discussed. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Emmanuel Gnandt
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstr. 21, 79104 Freiburg i. Br., Germany
| | - Katerina Dörner
- Deutsches Elektronen-Synchrotron DESY, CFEL, Notkestr. 85, Hamburg, Germany
| | - Marc F J Strampraad
- Delft University of Technology, Department of Biotechnology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Simon de Vries
- Delft University of Technology, Department of Biotechnology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Thorsten Friedrich
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstr. 21, 79104 Freiburg i. Br., Germany.
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19
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Bennett B, Helbling D, Meng H, Jarzembowski J, Geurts AM, Friederich MW, Van Hove JLK, Lawlor MW, Dimmock DP. Potentially diagnostic electron paramagnetic resonance spectra elucidate the underlying mechanism of mitochondrial dysfunction in the deoxyguanosine kinase deficient rat model of a genetic mitochondrial DNA depletion syndrome. Free Radic Biol Med 2016; 92:141-151. [PMID: 26773591 PMCID: PMC5047058 DOI: 10.1016/j.freeradbiomed.2016.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/04/2016] [Accepted: 01/06/2016] [Indexed: 01/19/2023]
Abstract
A novel rat model for a well-characterized human mitochondrial disease, mitochondrial DNA depletion syndrome with associated deoxyguanosine kinase (DGUOK) deficiency, is described. The rat model recapitulates the pathologic and biochemical signatures of the human disease. The application of electron paramagnetic (spin) resonance (EPR) spectroscopy to the identification and characterization of respiratory chain abnormalities in the mitochondria from freshly frozen tissue of the mitochondrial disease model rat is introduced. EPR is shown to be a sensitive technique for detecting mitochondrial functional abnormalities in situ and, here, is particularly useful in characterizing the redox state changes and oxidative stress that can result from depressed expression and/or diminished specific activity of the distinct respiratory chain complexes. As EPR requires no sample preparation or non-physiological reagents, it provides information on the status of the mitochondrion as it was in the functioning state. On its own, this information is of use in identifying respiratory chain dysfunction; in conjunction with other techniques, the information from EPR shows how the respiratory chain is affected at the molecular level by the dysfunction. It is proposed that EPR has a role in mechanistic pathophysiological studies of mitochondrial disease and could be used to study the impact of new treatment modalities or as an additional diagnostic tool.
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Affiliation(s)
- Brian Bennett
- National Biomedical EPR Center, Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Daniel Helbling
- Human Molecular Genetics Center and Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Hui Meng
- Division of Pediatric Pathology, Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Jason Jarzembowski
- Division of Pediatric Pathology, Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Marisa W Friederich
- Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Mailstop 8400, 13121 East 17th Avenue, Aurora, CO 80045, USA.
| | - Johan L K Van Hove
- Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Mailstop 8400, 13121 East 17th Avenue, Aurora, CO 80045, USA.
| | - Michael W Lawlor
- Division of Pediatric Pathology, Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - David P Dimmock
- Human Molecular Genetics Center and Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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20
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Berrisford JM, Baradaran R, Sazanov LA. Structure of bacterial respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:892-901. [PMID: 26807915 DOI: 10.1016/j.bbabio.2016.01.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 12/23/2022]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) plays a central role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation. It is the largest protein assembly of respiratory chains and one of the most elaborate redox membrane proteins known. Bacterial enzyme is about half the size of mitochondrial and thus provides its important "minimal" model. Dysfunction of mitochondrial complex I is implicated in many human neurodegenerative diseases. The L-shaped complex consists of a hydrophilic arm, where electron transfer occurs, and a membrane arm, where proton translocation takes place. We have solved the crystal structures of the hydrophilic domain of complex I from Thermus thermophilus, the membrane domain from Escherichia coli and recently of the intact, entire complex I from T. thermophilus (536 kDa, 16 subunits, 9 iron-sulphur clusters, 64 transmembrane helices). The 95Å long electron transfer pathway through the enzyme proceeds from the primary electron acceptor flavin mononucleotide through seven conserved Fe-S clusters to the unusual elongated quinone-binding site at the interface with the membrane domain. Four putative proton translocation channels are found in the membrane domain, all linked by the central flexible axis containing charged residues. The redox energy of electron transfer is coupled to proton translocation by the as yet undefined mechanism proposed to involve long-range conformational changes. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
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Affiliation(s)
| | - Rozbeh Baradaran
- Memorial Sloan-Kettering Cancer Center, 430 E 67th Street, NY 10065, USA
| | - Leonid A Sazanov
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
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21
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Hirst J, Roessler MM. Energy conversion, redox catalysis and generation of reactive oxygen species by respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:872-83. [PMID: 26721206 PMCID: PMC4893023 DOI: 10.1016/j.bbabio.2015.12.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 12/30/2022]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) is critical for respiration in mammalian mitochondria. It oxidizes NADH produced by the Krebs' tricarboxylic acid cycle and β-oxidation of fatty acids, reduces ubiquinone, and transports protons to contribute to the proton-motive force across the inner membrane. Complex I is also a significant contributor to cellular oxidative stress. In complex I, NADH oxidation by a flavin mononucleotide, followed by intramolecular electron transfer along a chain of iron–sulfur clusters, delivers electrons and energy to bound ubiquinone. Either at cluster N2 (the terminal cluster in the chain) or upon the binding/reduction/dissociation of ubiquinone/ubiquinol, energy from the redox process is captured to initiate long-range energy transfer through the complex and drive proton translocation. This review focuses on current knowledge of how the redox reaction and proton transfer are coupled, with particular emphasis on the formation and role of semiquinone intermediates in both energy transduction and reactive oxygen species production. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. Current knowledge of the redox reactions catalyzed by complex I is reviewed. Possible quinone reduction pathways are presented. The presence and number of semiquinone intermediates are deliberated. The involvement of cluster N2/semiquinones in coupled proton transfer is discussed. Evidence for reactive oxygen species production by semiquinones is examined.
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Affiliation(s)
- Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
| | - Maxie M Roessler
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.
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22
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Morra S, Maurelli S, Chiesa M, Mulder DW, Ratzloff MW, Giamello E, King PW, Gilardi G, Valetti F. The effect of a C298D mutation in CaHydA [FeFe]-hydrogenase: Insights into the protein-metal cluster interaction by EPR and FTIR spectroscopic investigation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:98-106. [PMID: 26482707 DOI: 10.1016/j.bbabio.2015.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/01/2015] [Accepted: 10/15/2015] [Indexed: 01/17/2023]
Abstract
A conserved cysteine located in the signature motif of the catalytic center (H-cluster) of [FeFe]-hydrogenases functions in proton transfer. This residue corresponds to C298 in Clostridium acetobutylicum CaHydA. Despite the chemical and structural difference, the mutant C298D retains fast catalytic activity, while replacement with any other amino acid causes significant activity loss. Given the proximity of C298 to the H-cluster, the effect of the C298D mutation on the catalytic center was studied by continuous wave (CW) and pulse electron paramagnetic resonance (EPR) and by Fourier transform infrared (FTIR) spectroscopies. Comparison of the C298D mutant with the wild type CaHydA by CW and pulse EPR showed that the electronic structure of the center is not altered. FTIR spectroscopy confirmed that absorption peak values observed in the mutant are virtually identical to those observed in the wild type, indicating that the H-cluster is not generally affected by the mutation. Significant differences were observed only in the inhibited state Hox-CO: the vibrational modes assigned to the COexo and Fed-CO in this state are shifted to lower values in C298D, suggesting different interaction of these ligands with the protein moiety when C298 is changed to D298. More relevant to the catalytic cycle, the redox equilibrium between the Hox and Hred states is modified by the mutation, causing a prevalence of the oxidized state. This work highlights how the interactions between the protein environment and the H-cluster, a dynamic closely interconnected system, can be engineered and studied in the perspective of designing bio-inspired catalysts and mimics.
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Affiliation(s)
- Simone Morra
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Sara Maurelli
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Mario Chiesa
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael W Ratzloff
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Elio Giamello
- Department of Chemistry, University of Torino, Torino 10133, Italy
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy
| | - Francesca Valetti
- Department of Life Sciences and Systems Biology, University of Torino, Torino 10133, Italy.
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Tellurite-mediated damage to the Escherichia coli NDH-dehydrogenases and terminal oxidases in aerobic conditions. Arch Biochem Biophys 2015; 566:67-75. [DOI: 10.1016/j.abb.2014.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/27/2014] [Accepted: 10/19/2014] [Indexed: 11/20/2022]
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Sato M, Torres-Bacete J, Sinha PK, Matsuno-Yagi A, Yagi T. Essential regions in the membrane domain of bacterial complex I (NDH-1): the machinery for proton translocation. J Bioenerg Biomembr 2014; 46:279-87. [PMID: 24973951 DOI: 10.1007/s10863-014-9558-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 06/18/2014] [Indexed: 01/09/2023]
Abstract
The proton-translocating NADH-quinone oxidoreductase (complex I/NDH-1) is the first and largest enzyme of the respiratory chain which has a central role in cellular energy production and is implicated in many human neurodegenerative diseases and aging. It is believed that the peripheral domain of complex I/NDH-1 transfers the electron from NADH to Quinone (Q) and the redox energy couples the proton translocation in the membrane domain. To investigate the mechanism of the proton translocation, in a series of works we have systematically studied all membrane subunits in the Escherichia coli NDH-1 by site-directed mutagenesis. In this mini-review, we have summarized our strategy and results of the mutagenesis by depicting residues essential for proton translocation, along with those for subunit connection. It is suggested that clues to understanding the driving forces of proton translocation lie in the similarities and differences of the membrane subunits, highlighting the communication of essential charged residues among the subunits. A possible proton translocation mechanism with all membrane subunits operating in unison is described.
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Affiliation(s)
- Motoaki Sato
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, CA, 92037, USA,
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Investigating the function of [2Fe-2S] cluster N1a, the off-pathway cluster in complex I, by manipulating its reduction potential. Biochem J 2013; 456:139-46. [PMID: 23980528 PMCID: PMC3898324 DOI: 10.1042/bj20130606] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
NADH:quinone oxidoreductase (complex I) couples NADH oxidation and quinone reduction to proton translocation across an energy-transducing membrane. All complexes I contain a flavin to oxidize NADH, seven iron–sulfur clusters to transfer electrons from the flavin to quinone and an eighth cluster (N1a) on the opposite side of the flavin. The role of cluster N1a is unknown, but Escherichia coli complex I has an unusually high-potential cluster N1a and its reduced flavin produces H2O2, not superoxide, suggesting that cluster N1a may affect reactive oxygen species production. In the present study, we combine protein film voltammetry with mutagenesis in overproduced N1a-binding subunits to identify two residues that switch N1a between its high- (E. coli, valine and asparagine) and low- (Bos taurus and Yarrowia lipolytica, proline and methionine) potential forms. The mutations were incorporated into E. coli complex I: cluster N1a could no longer be reduced by NADH, but H2O2 and superoxide production were unaffected. The reverse mutations (that increase the potential by ~0.16 V) were incorporated into Y. lipolytica complex I, but N1a was still not reduced by NADH. We conclude that cluster N1a does not affect reactive oxygen species production by the complex I flavin; it is probably required for enzyme assembly or stability. Two residues that determine the potential of cluster N1a in respiratory complex I were identified, and their effects on its flavin-site reactions were determined. Reduction of cluster N1a by NADH does not affect reactive oxygen species production by the flavin.
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26
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Sato M, Sinha PK, Torres-Bacete J, Matsuno-Yagi A, Yagi T. Energy transducing roles of antiporter-like subunits in Escherichia coli NDH-1 with main focus on subunit NuoN (ND2). J Biol Chem 2013; 288:24705-16. [PMID: 23864658 DOI: 10.1074/jbc.m113.482968] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proton-translocating NADH-quinone oxidoreductase (complex I/NDH-1) contains a peripheral and a membrane domain. Three antiporter-like subunits in the membrane domain, NuoL, NuoM, and NuoN (ND5, ND4 and ND2, respectively), are structurally similar. We analyzed the role of NuoN in Escherichia coli NDH-1. The lysine residue at position 395 in NuoN (NLys(395)) is conserved in NuoL (LLys(399)) but is replaced by glutamic acid (MGlu(407)) in NuoM. Our mutation study on NLys(395) suggests that this residue participates in the proton translocation. Furthermore, we found that MGlu(407) is also essential and most likely interacts with conserved LArg(175). Glutamic acids, NGlu(133), MGlu(144), and LGlu(144), are corresponding residues. Unlike mutants of MGlu(144) and LGlu(144), mutation of NGlu(133) scarcely affected the energy-transducing activities. However, a double mutant of NGlu(133) and nearby KGlu(72) showed significant inhibition of these activities. This suggests that NGlu(133) bears a functional role similar to LGlu(144) and MGlu(144) but its mutation can be partially compensated by the nearby carboxyl residue. Conserved prolines located at loops of discontinuous transmembrane helices of NuoL, NuoM, and NuoN were shown to play a similar role in the energy-transducing activity. It seems likely that NuoL, NuoM, and NuoN pump protons by a similar mechanism. Our data also revealed that NLys(158) is one of the key interaction points with helix HL in NuoL. A truncation study indicated that the C-terminal amphipathic segments of NTM14 interacts with the Mβ sheet located on the opposite side of helix HL. Taken together, the mechanism of H(+) translocation in NDH-1 is discussed.
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Affiliation(s)
- Motoaki Sato
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037, USA
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27
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Narayanan M, Gabrieli DJ, Leung SA, Elguindy MM, Glaser CA, Saju N, Sinha SC, Nakamaru-Ogiso E. Semiquinone and cluster N6 signals in His-tagged proton-translocating NADH:ubiquinone oxidoreductase (complex I) from Escherichia coli. J Biol Chem 2013; 288:14310-14319. [PMID: 23543743 DOI: 10.1074/jbc.m113.467803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (complex I) pumps protons across the membrane using downhill redox energy. The Escherichia coli complex I consists of 13 different subunits named NuoA-N coded by the nuo operon. Due to the low abundance of the protein and some difficulty with the genetic manipulation of its large ~15-kb operon, purification of E. coli complex I has been technically challenging. Here, we generated a new strain in which a polyhistidine sequence was inserted upstream of nuoE in the operon. This allowed us to prepare large amounts of highly pure and active complex I by efficient affinity purification. The purified complex I contained 0.94 ± 0.1 mol of FMN, 29.0 ± 0.37 mol of iron, and 1.99 ± 0.07 mol of ubiquinone/1 mol of complex I. The extinction coefficient of isolated complex I was 495 mM(-1) cm(-1) at 274 nm and 50.3 mM(-1) cm(-1) at 410 nm. NADH:ferricyanide activity was 219 ± 9.7 μmol/min/mg by using HEPES-Bis-Tris propane, pH 7.5. Detailed EPR analyses revealed two additional iron-sulfur cluster signals, N6a and N6b, in addition to previously assigned signals. Furthermore, we found small but significant semiquinone signal(s), which have been reported only for bovine complex I. The line width was ~12 G, indicating its neutral semiquinone form. More than 90% of the semiquinone signal originated from the single entity with P½ (half-saturation power level) = 1.85 milliwatts. The semiquinone signal(s) decreased by 60% when with asimicin, a potent complex I inhibitor. The functional role of semiquinone and the EPR assignment of clusters N6a/N6b are discussed.
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Affiliation(s)
- Madhavan Narayanan
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - David J Gabrieli
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Steven A Leung
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Mahmoud M Elguindy
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Carl A Glaser
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Nitha Saju
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Subhash C Sinha
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Eiko Nakamaru-Ogiso
- Johnson Research Foundation, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
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28
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Abstract
Complex I (NADH:ubiquinone oxidoreductase) is crucial for respiration in many aerobic organisms. In mitochondria, it oxidizes NADH from the tricarboxylic acid cycle and β-oxidation, reduces ubiquinone, and transports protons across the inner membrane, contributing to the proton-motive force. It is also a major contributor to cellular production of reactive oxygen species. The redox reaction of complex I is catalyzed in the hydrophilic domain; it comprises NADH oxidation by a flavin mononucleotide, intramolecular electron transfer along a chain of iron-sulfur clusters, and ubiquinone reduction. Redox-coupled proton translocation in the membrane domain requires long-range energy transfer through the protein complex, and the molecular mechanisms that couple the redox and proton-transfer half-reactions are currently unknown. This review evaluates extant data on the mechanisms of energy transduction and superoxide production by complex I, discusses contemporary mechanistic models, and explores how mechanistic studies may contribute to understanding the roles of complex I dysfunctions in human diseases.
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Affiliation(s)
- Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom.
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29
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Verkhovskaya M, Bloch DA. Energy-converting respiratory Complex I: on the way to the molecular mechanism of the proton pump. Int J Biochem Cell Biol 2012; 45:491-511. [PMID: 22982742 DOI: 10.1016/j.biocel.2012.08.024] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/27/2012] [Accepted: 08/28/2012] [Indexed: 12/16/2022]
Abstract
In respiring organisms the major energy transduction flux employs the transmembrane electrochemical proton gradient as a physical link between exergonic redox reactions and endergonic ADP phosphorylation. Establishing the gradient involves electrogenic, transmembrane H(+) translocation by the membrane-embedded respiratory complexes. Among others, Complex I (NADH:ubiquinone oxidoreductase) is the most structurally complex and functionally enigmatic respiratory enzyme; its molecular mechanism is as yet unknown. Here we highlight recent progress and discuss the catalytic events during Complex I turnover in relation to their role in energy conversion and to the enzyme structure.
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Affiliation(s)
- Marina Verkhovskaya
- Helsinki Bioenergetics Group, Institute of Biotechnology, PO Box 65 (Viikinkaari 1) FIN-00014 University of Helsinki, Finland.
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30
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Sinha PK, Nakamaru-Ogiso E, Torres-Bacete J, Sato M, Castro-Guerrero N, Ohnishi T, Matsuno-Yagi A, Yagi T. Electron transfer in subunit NuoI (TYKY) of Escherichia coli NADH:quinone oxidoreductase (NDH-1). J Biol Chem 2012; 287:17363-17373. [PMID: 22474289 DOI: 10.1074/jbc.m111.329649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial proton-translocating NADH:quinone oxidoreductase (NDH-1) consists of a peripheral and a membrane domain. The peripheral domain catalyzes the electron transfer from NADH to quinone through a chain of seven iron-sulfur (Fe/S) clusters. Subunit NuoI in the peripheral domain contains two [4Fe-4S] clusters (N6a and N6b) and plays a role in bridging the electron transfer from cluster N5 to the terminal cluster N2. We constructed mutants for eight individual Cys-coordinating Fe/S clusters. With the exception of C63S, all mutants had damaged architecture of NDH-1, suggesting that Cys-coordinating Fe/S clusters help maintain the NDH-1 structure. Studies of three mutants (C63S-coordinating N6a, P110A located near N6a, and P71A in the vicinity of N6b) were carried out using EPR measurement. These three mutations did not affect the EPR signals from [2Fe-2S] clusters and retained electron transfer activities. Signals at g(z) = 2.09 disappeared in C63S and P110A but not in P71A. Considering our data together with the available information, g(z,x) = 2.09, 1.88 signals are assigned to cluster N6a. It is of interest that, in terms of g(z,x) values, cluster N6a is similar to cluster N4. In addition, we investigated the residues (Ile-94 and Ile-100) that are predicted to serve as electron wires between N6a and N6b and between N6b and N2, respectively. Replacement of Ile-100 and Ile-94 with Ala/Gly did not affect the electron transfer activity significantly. It is concluded that conserved Ile-100 and Ile-94 are not essential for the electron transfer.
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Affiliation(s)
- Prem Kumar Sinha
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Eiko Nakamaru-Ogiso
- Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jesus Torres-Bacete
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Motoaki Sato
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Norma Castro-Guerrero
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Tomoko Ohnishi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Akemi Matsuno-Yagi
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Takao Yagi
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037.
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31
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Bridges HR, Bill E, Hirst J. Mössbauer spectroscopy on respiratory complex I: the iron-sulfur cluster ensemble in the NADH-reduced enzyme is partially oxidized. Biochemistry 2011; 51:149-58. [PMID: 22122402 PMCID: PMC3254188 DOI: 10.1021/bi201644x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
In mitochondria, complex I (NADH:quinone oxidoreductase)
couples
electron transfer to proton translocation across an energy-transducing
membrane. It contains a flavin mononucleotide to oxidize NADH, and
an unusually long series of iron–sulfur (FeS) clusters that
transfer the electrons to quinone. Understanding electron transfer
in complex I requires spectroscopic and structural data to be combined
to reveal the properties of individual clusters and of the ensemble.
EPR studies on complex I from Bos taurus have established
that five clusters (positions 1, 2, 3, 5, and 7 along the seven-cluster
chain extending from the flavin) are (at least partially) reduced
by NADH. The other three clusters, positions 4 and 6 plus a cluster
on the other side of the flavin, are not observed in EPR spectra from
the NADH-reduced enzyme: they may remain oxidized, have unusual or
coupled spin states, or their EPR signals may be too fast relaxing.
Here, we use Mössbauer spectroscopy on 57Fe-labeled
complex I from the mitochondria of Yarrowia lipolytica to show that the cluster ensemble is only partially reduced in the
NADH-reduced enzyme. The three EPR-silent clusters are oxidized, and
only the terminal 4Fe cluster (position 7) is fully reduced. Together
with the EPR analyses, our results reveal an alternating profile of
higher and lower potential clusters between the two active sites in
complex I; they are not consistent with the consensus picture of a
set of isopotential clusters. The implications for intramolecular
electron transfer along the extended chain of cofactors in complex
I are discussed.
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Affiliation(s)
- Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
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32
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A two-state stabilization-change mechanism for proton-pumping complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1364-9. [DOI: 10.1016/j.bbabio.2011.04.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Revised: 04/17/2011] [Accepted: 04/19/2011] [Indexed: 11/18/2022]
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Torres-Bacete J, Sinha PK, Matsuno-Yagi A, Yagi T. Structural contribution of C-terminal segments of NuoL (ND5) and NuoM (ND4) subunits of complex I from Escherichia coli. J Biol Chem 2011; 286:34007-14. [PMID: 21835926 DOI: 10.1074/jbc.m111.260968] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proton-translocating NADH-quinone oxidoreductase (complex I/NDH-1) is a multisubunit enzymatic complex. It has a characteristic L-shaped form with two domains, a hydrophilic peripheral domain and a hydrophobic membrane domain. The membrane domain contains three antiporter-like subunits (NuoL, NuoM, and NuoN, Escherichia coli naming) that are considered to be involved in the proton translocation. Deletion of either NuoL or NuoM resulted in an incomplete assembly of NDH-1 and a total loss of the NADH-quinone oxidoreductase activity. We have truncated the C terminus segments of NuoM and NuoL by introducing STOP codons at different locations using site-directed mutagenesis of chromosomal DNA. Our results suggest an important structural role for the C-terminal segments of both subunits. The data further advocate that the elimination of the last transmembrane helix (TM14) of NuoM and the TM16 (at least C-terminal seven residues) or together with the HL helix and the TM15 of the NuoL subunit lead to reduced stability of the membrane arm and therefore of the whole NDH-1 complex. A region of NuoL critical for stability of NDH-1 architecture has been discussed.
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Affiliation(s)
- Jesus Torres-Bacete
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037, USA
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34
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Michel J, DeLeon-Rangel J, Zhu S, Van Ree K, Vik SB. Mutagenesis of the L, M, and N subunits of Complex I from Escherichia coli indicates a common role in function. PLoS One 2011; 6:e17420. [PMID: 21387012 PMCID: PMC3046159 DOI: 10.1371/journal.pone.0017420] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 01/24/2011] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The membrane arm of Complex I (NADH:ubiquinone oxidoreductase) contains three large, and closely related subunits, which are called L, M, and N in E. coli. These subunits are homologous to components of multi-subunit Na(+)/H(+) antiporters, and so are implicated in proton translocation. METHODOLOGY/PRINCIPAL FINDINGS Nineteen site-specific mutations were constructed at two corresponding positions in each of the three subunits. Two positions were selected in each subunit: L_K169, M_K173, N_K158 and L_Q236, M_H241, N_H224. Membrane vesicles were prepared from all of the resulting mutant strains, and were assayed for deamino-NADH oxidase activity, proton translocation, ferricyanide reductase activity, and sensitivity to capsaicin. Corresponding mutations in the three subunits were found to have very similar effects on all activities measured. In addition, the effect of adding exogenous decylubiquinone on these activities was tested. 50 µM decylubiquinone stimulated both deamino-NADH oxidase activity and proton translocation by wild type membrane vesicles, but was inhibitory towards the same activities by membrane vesicles bearing the lysine substitution at the L236/M241/N224 positions. CONCLUSIONS/SIGNIFICANCE The results show a close correlation with reduced activity among the corresponding mutations, and provide evidence that the L, M, and N subunits have a common role in Complex I.
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Affiliation(s)
- Jose Michel
- Department of Biological Sciences, Southern Methodist University, Dallas,
Texas, United States of America
| | - Jessica DeLeon-Rangel
- Department of Biological Sciences, Southern Methodist University, Dallas,
Texas, United States of America
| | - Shaotong Zhu
- Department of Biological Sciences, Southern Methodist University, Dallas,
Texas, United States of America
| | - Kalie Van Ree
- Department of Biological Sciences, Southern Methodist University, Dallas,
Texas, United States of America
| | - Steven B. Vik
- Department of Biological Sciences, Southern Methodist University, Dallas,
Texas, United States of America
- * E-mail:
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35
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Myers JM, Antholine WE, Myers CR. The intracellular redox stress caused by hexavalent chromium is selective for proteins that have key roles in cell survival and thiol redox control. Toxicology 2011; 281:37-47. [PMID: 21237240 DOI: 10.1016/j.tox.2011.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/22/2010] [Accepted: 01/04/2011] [Indexed: 01/14/2023]
Abstract
Hexavalent chromium [Cr(VI)] compounds (e.g. chromates) are strong oxidants that readily enter cells where they are reduced to reactive Cr intermediates that can directly oxidize some cell components and can promote the generation of reactive oxygen and nitrogen species. Inhalation is a major route of exposure which directly exposes the bronchial epithelium. Previous studies with non-cancerous human bronchial epithelial cells (BEAS-2B) demonstrated that Cr(VI) treatment results in the irreversible inhibition of thioredoxin reductase (TrxR) and the oxidation of thioredoxins (Trx) and peroxiredoxins (Prx). The mitochondrial Trx/Prx system is somewhat more sensitive to Cr(VI) than the cytosolic Trx/Prx system, and other redox-sensitive mitochondrial functions are subsequently affected including electron transport complexes I and II. Studies reported here show that Cr(VI) does not cause indiscriminant thiol oxidation, and that the Trx/Prx system is among the most sensitive of cellular protein thiols. Trx/Prx oxidation is not unique to BEAS-2B cells, as it was also observed in primary human bronchial epithelial cells. Increasing the intracellular levels of ascorbate, an endogenous Cr(VI) reductant, did not alter the effects on TrxR, Trx, or Prx. The peroxynitrite scavenger MnTBAP did not protect TrxR, Trx, Prx, or the electron transport chain from the effects of Cr(VI), implying that peroxynitrite is not required for these effects. Nitration of tyrosine residues of TrxR was not observed following Cr(VI) treatment, further ruling out peroxynitrite as a significant contributor to the irreversible inhibition of TrxR. Cr(VI) treatments that disrupt the TrxR/Trx/Prx system did not cause detectable mitochondrial DNA damage. Overall, the redox stress that results from Cr(VI) exposure shows selectivity for key proteins which are known to be important for redox signaling, antioxidant defense, and cell survival.
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Affiliation(s)
- Judith M Myers
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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36
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Abstract
A review is presented of some of the ways in which electron spin resonance (ESR) spectroscopy may be useful to investigate systems of relevance to the biomedical sciences. Specifically considered are: spin-trapping in biological media; the determination of antioxidant efficiencies; lipid-peroxidation; the use of nitroxides as probes of metabolic activity in cells and as structumral probes of cell-membranes; ESR coupled with materials for radiation-dosimetry; food- and drug-irradiation; studies of enzyme systems and ofcyclodextrins; diagnosis of cancer and rheumatoid arthritis; measurement of oxidative stress in synovial tissue in preparation for joint replacement; determination of oxidative species during kidney dialysis; measurement of biological oxygen concentrations (oximetry); trapping in living cells of the endothelium-derived relaxing factor nitric oxide (NO); measurement of hydrogen peroxide; determination of drugs of abuse (opiates); ESR measurements of whole blood and as a means to determine the age of bloodstains for forensic analysis are surveyed, and also a determination of the aqueous volume of human sperm cells is described, among other topics.
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37
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Myers CR, Antholine WE, Myers JM. The pro-oxidant chromium(VI) inhibits mitochondrial complex I, complex II, and aconitase in the bronchial epithelium: EPR markers for Fe-S proteins. Free Radic Biol Med 2010; 49:1903-15. [PMID: 20883776 PMCID: PMC3005768 DOI: 10.1016/j.freeradbiomed.2010.09.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 08/27/2010] [Accepted: 09/20/2010] [Indexed: 11/26/2022]
Abstract
Hexavalent chromium (Cr(VI)) compounds (e.g., chromates) are strong oxidants that readily enter cells, where they are reduced to reactive Cr species that also facilitate reactive oxygen species generation. Recent studies demonstrated inhibition and oxidation of the thioredoxin system, with greater effects on mitochondrial thioredoxin (Trx2). This implies that Cr(VI)-induced oxidant stress may be especially directed at the mitochondria. Examination of other redox-sensitive mitochondrial functions showed that Cr(VI) treatments that cause Trx2 oxidation in human bronchial epithelial cells also result in pronounced and irreversible inhibition of aconitase, a TCA cycle enzyme that has an iron-sulfur (Fe-S) center that is labile with respect to certain oxidants. The activities of electron transport complexes I and II were also inhibited, whereas complex III was not. Electron paramagnetic resonance (EPR) studies of samples at liquid helium temperature (10K) showed a strong signal at g=1.94 that is consistent with the inhibition of electron flow through complex I and/or II. A signal at g=2.02 was also observed, which is consistent with oxidation of the Fe-S center of aconitase. The g=1.94 signal was particularly intense and remained after extracellular Cr(VI) was removed, whereas the g=2.02 signal declined in intensity after Cr(VI) was removed. A similar inhibition of these activities and analogous EPR findings were noted in bovine airways treated ex vivo with Cr(VI). Overall, the data support the hypothesis that Cr(VI) exposure has deleterious effects on a number of redox-sensitive core mitochondrial proteins. The g=1.94 signal could prove to be an important biomarker for oxidative damage resulting from Cr(VI) exposure. The EPR spectra simultaneously showed signals for Cr(V) and Cr(III), which verify Cr(VI) exposure and its intracellular reductive activation.
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Affiliation(s)
- Charles R Myers
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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38
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Bolstad HM, Botelho DJ, Wood MJ. Proteomic analysis of protein-protein interactions within the Cysteine Sulfinate Desulfinase Fe-S cluster biogenesis system. J Proteome Res 2010; 9:5358-69. [PMID: 20734996 DOI: 10.1021/pr1006087] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fe-S cluster biogenesis is of interest to many fields, including bioenergetics and gene regulation. The CSD system is one of three Fe-S cluster biogenesis systems in E. coli and is comprised of the cysteine desulfurase CsdA, the sulfur acceptor protein CsdE, and the E1-like protein CsdL. The biological role, biochemical mechanism, and protein targets of the system remain uncharacterized. Here we present that the active site CsdE C61 has a lowered pK(a) value of 6.5, which is nearly identical to that of C51 in the homologous SufE protein and which is likely critical for its function. We observed that CsdE forms disulfide bonds with multiple proteins and identified the proteins that copurify with CsdE. The identification of Fe-S proteins and both putative and established Fe-S cluster assembly (ErpA, glutaredoxin-3, glutaredoxin-4) and sulfur trafficking (CsdL, YchN) proteins supports the two-pathway model, in which the CSD system is hypothesized to synthesize both Fe-S clusters and other sulfur-containing cofactors. We suggest that the identified Fe-S cluster assembly proteins may be the scaffold and/or shuttle proteins for the CSD system. By comparison with previous analysis of SufE, we demonstrate that there is some overlap in the CsdE and SufE interactomes.
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Affiliation(s)
- Heather M Bolstad
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA
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39
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Spin labeling of the Escherichia coli NADH ubiquinone oxidoreductase (complex I). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1894-900. [PMID: 20959113 DOI: 10.1016/j.bbabio.2010.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 09/29/2010] [Accepted: 10/13/2010] [Indexed: 11/20/2022]
Abstract
The proton-pumping NADH:ubiquinone oxidoreductase, the respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. Electron microscopy revealed the two-part structure of the complex with a peripheral arm involved in electron transfer and a membrane arm most likely involved in proton translocation. It was proposed that the quinone binding site is located at the joint of the two arms. Most likely, proton translocation in the membrane arm is enabled by the energy of the electron transfer reaction in the peripheral arm transmitted by conformational changes. For the detection of the conformational changes and the localization of the quinone binding site, we set up a combination of site-directed spin labeling and EPR spectroscopy. Cysteine residues were introduced to the surface of the Escherichia coli complex I. The spin label (1-oxyl-2,2,5,5-tetramethyl-Δ3-pyrroline-3-methyl)-methanethiosulfonate (MTSL) was exclusively bound to the engineered positions. Neither the mutation nor the labeling had an effect on the NADH:decyl-ubiquinone oxidoreductase activity. The characteristic signals of the spin label were detected by EPR spectroscopy, which did not change by reducing the preparation with NADH. A decyl-ubiquinone derivative with the spin label covalently attached to the alkyl chain was synthesized in order to localize the quinone binding site. The distance between a MTSL labeled complex I variant and the bound quinone was determined by continuous-wave (cw) EPR allowing an inference on the location of the quinone binding site. The distances between the labeled quinone and other complex I variants will be determined in future experiments to receive further geometry information by triangulation.
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The reaction of NADPH with bovine mitochondrial NADH:ubiquinone oxidoreductase revisited: I. Proposed consequences for electron transfer in the enzyme. J Bioenerg Biomembr 2010; 42:261-78. [PMID: 20628895 DOI: 10.1007/s10863-010-9301-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
Bovine NADH:ubiquinone oxidoreductase (Complex I) is the first complex in the mitochondrial respiratory chain. It has long been assumed that it contained only one FMN group. However, as demonstrated in 2003, the intact enzyme contains two FMN groups. The second FMN was proposed to be located in a conserved flavodoxin fold predicted to be present in the PSST subunit. The long-known reaction of Complex I with NADPH differs in many aspects from that with NADH. It was proposed that the second flavin group was specifically involved in the reaction with NADPH. The X-ray structure of the hydrophilic domain of Complex I from Thermus thermophilus (Sazanov and Hinchliffe 2006, Science 311, 1430-1436) disclosed the positions of all redox groups of that enzyme and of the subunits holding them. The PSST subunit indeed contains the predicted flavodoxin fold although it did not contain FMN. Inspired by this structure, the present paper describes a re-evaluation of the enigmatic reactions of the bovine enzyme with NADPH. Published data, as well as new freeze-quench kinetic data presented here, are incompatible with the general opinion that NADPH and NADH react at the same site. Instead, it is proposed that these pyridine nucleotides react at opposite ends of the 90 A long chain of prosthetic groups in Complex I. Ubiquinone is proposed to react with the Fe-S clusters in the TYKY subunit deep inside the hydrophilic domain. A new model for electron transfer in Complex I is proposed. In the accompanying paper this model is compared with the one advocated in current literature.
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Medvedev ES, Couch VA, Stuchebrukhov AA. Determination of the intrinsic redox potentials of FeS centers of respiratory complex I from experimental titration curves. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1665-71. [PMID: 20513348 DOI: 10.1016/j.bbabio.2010.05.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 05/17/2010] [Accepted: 05/24/2010] [Indexed: 11/19/2022]
Abstract
Recently, Euro et al. [Biochem. 47, 3185 (2008) ] have reported titration data for seven of nine FeS redox centers of complex I from Escherichiacoli. There is a significant uncertainty in the assignment of the titration data. Four of the titration curves were assigned to N1a, N1b, N6b, and N2 centers; one curve either to N3 or N7; one more either to N4 or N5; and the last one denoted Nx could not be assigned at all. In addition, the assignment of the titration data to the N6b/N6a pair is also uncertain. In this paper, using our calculated interaction energies [Couch et al. BBA 1787, 1266 (2009)], we perform statistical analysis of these data, considering a variety of possible assignments, find the best fit, and determine the intrinsic redox potentials of the centers. The intrinsic potentials could be determined with an uncertainty of less than +/-10 mV at a 95% confidence level for best fit assignments. We also find that the best agreement between theoretical and experimental titration curves is obtained with the N6b-N2 interaction equal to 71+/-14 or 96+/-26 mV depending on the N6b/N6a titration data assignment, which is stronger than was expected and may indicate a close distance of the N2 center to the membrane surface.
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Affiliation(s)
- Emile S Medvedev
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia
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Ransac S, Arnarez C, Mazat JP. The flitting of electrons in complex I: a stochastic approach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:641-8. [PMID: 20230777 DOI: 10.1016/j.bbabio.2010.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Revised: 02/19/2010] [Accepted: 03/06/2010] [Indexed: 12/12/2022]
Abstract
A stochastic approach based on the Gillespie algorithm is particularly well adapted to describe the time course of the redox reactions that occur inside the respiratory chain complexes because they involve the motion of single electrons between the individual unique redox centres of a given complex. We use this approach to describe the molecular functioning of the peripheral arm of complex I based on its known crystallographic structure and the rate constants of electron tunnelling derived from the Moser and Dutton phenomenological equations. There are several possible electrons pathways but we show that most of them take the route defined by the successive sites and redox centres: NADH+ site-FMN-N3-N1b-N4-N5-N6a-N6b-N2-Q site. However, the electrons do not go directly from NADH towards the ubiquinone molecule. They frequently jump back and forth between neighbouring redox centres with the result that the net flux of electrons through complex I (i.e. net number of electrons reducing a ubiquinone) is far smaller than the number of redox reactions which actually occur. While most of the redox centres are reduced in our simulations the degree of reduction can vary according to the individual midpoint potentials. The high turnover number observed in our simulation seems to indicate that, in the whole complex I, one or several slower step(s) follow(s) the redox reactions involved in the peripheral arm. It also appears that the residence time of FMNH* and SQ* (possible producers of ROS) is low (around 4% and between 1.6% and 5% respectively according to the values of the midpoint potentials). We did not find any evidence for a role of N7 which remains mainly reduced in our simulations. The role of N1a is complex and depends upon its midpoint potential. In all cases its presence slightly decreases the life time of the flavosemiquinone species. These simulations demonstrate the interest of this type of model which links the molecular physico-chemistry of the individual redox reactions to the more global level of the reaction, as is observed experimentally.
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Affiliation(s)
- Stéphane Ransac
- Université de Bordeaux 2, Mitochondrial physiopathology laboratory, INSERM U688, Bordeaux, France
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Lyubenova S, Maly T, Zwicker K, Brandt U, Ludwig B, Prisner T. Multifrequency pulsed electron paramagnetic resonance on metalloproteins. Acc Chem Res 2010; 43:181-9. [PMID: 19842617 DOI: 10.1021/ar900050d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metalloproteins often contain metal centers that are paramagnetic in some functional state of the protein; hence electron paramagnetic resonance (EPR) spectroscopy can be a powerful tool for studying protein structure and function. Dipolar spectroscopy allows the determination of the dipole-dipole interactions between metal centers in protein complexes, revealing the structural arrangement of different paramagnetic centers at distances of up to 8 nm. Hyperfine spectroscopy can be used to measure the interaction between an unpaired electron spin and nuclear spins within a distance of 0.8 nm; it therefore permits the characterization of the local structure of the paramagnetic center's ligand sphere with very high precision. In this Account, we review our laboratory's recent applications of both dipolar and hyperfine pulsed EPR methods to metalloproteins. We used pulsed dipolar relaxation methods to investigate the complex of cytochrome c and cytochrome c oxidase, a noncovalent protein-protein complex involved in mitochondrial electron-transfer reactions. Hyperfine sublevel correlation spectroscopy (HYSCORE) was used to study the ligand sphere of iron-sulfur clusters in complex I of the mitochondrial respiratory chain and substrate binding to the molybdenum enzyme polysulfide reductase. These examples demonstrate the potential of the two techniques; however, they also highlight the difficulties of data interpretation when several paramagnetic species with overlapping spectra are present in the protein. In such cases, further approaches and data are very useful to enhance the information content. Relaxation filtered hyperfine spectroscopy (REFINE) can be used to separate the individual components of overlapping paramagnetic species on the basis of differences in their longitudinal relaxation rates; it is applicable to any kind of pulsed hyperfine or dipolar spectroscopy. Here, we show that the spectra of the iron-sulfur clusters in complex I can be separated by this method, allowing us to obtain hyperfine (and dipolar) information from the individual species. Furthermore, performing pulsed EPR experiments at different magnetic fields is another important tool to disentangle the spectral components in such complex systems. Despite the fact that high magnetic fields do not usually lead to better spectral separation for metal centers, they provide additional information about the relative orientation of different paramagnetic centers. Our high-field EPR studies on cytochrome c oxidase reveal essential information regarding the structural arrangement of the binuclear Cu(A) center with respect to both the manganese ion within the enzyme and the cytochrome in the protein-protein complex with cytochrome c.
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Affiliation(s)
- Sevdalina Lyubenova
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
| | - Thorsten Maly
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
| | - Klaus Zwicker
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
| | - Ulrich Brandt
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
| | - Bernd Ludwig
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
| | - Thomas Prisner
- Cluster of Excellence Macromolecular Complexes, Goethe-University, Frankfurt am Main, Germany
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Roessler MM, King MS, Robinson AJ, Armstrong FA, Harmer J, Hirst J. Direct assignment of EPR spectra to structurally defined iron-sulfur clusters in complex I by double electron-electron resonance. Proc Natl Acad Sci U S A 2010; 107:1930-5. [PMID: 20133838 PMCID: PMC2808219 DOI: 10.1073/pnas.0908050107] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In oxidative phosphorylation, complex I (NADH:quinone oxidoreductase) couples electron transfer to proton translocation across an energy-transducing membrane. Complex I contains a flavin mononucleotide to oxidize NADH, and an unusually long series of iron-sulfur (FeS) clusters, in several subunits, to transfer the electrons to quinone. Understanding coupled electron transfer in complex I requires a detailed knowledge of the properties of individual clusters and of the cluster ensemble, and so it requires the correlation of spectroscopic and structural data: This has proved a challenging task. EPR studies on complex I from Bos taurus have established that EPR signals N1b, N2 and N3 arise, respectively, from the 2Fe cluster in the 75 kDa subunit, and from 4Fe clusters in the PSST and 51 kDa subunits (positions 2, 7, and 1 along the seven-cluster chain extending from the flavin). The other clusters have either evaded detection or definitive signal assignments have not been established. Here, we combine double electron-electron resonance (DEER) spectroscopy on B. taurus complex I with the structure of the hydrophilic domain of Thermus thermophilus complex I. By considering the magnetic moments of the clusters and the orientation selectivity of the DEER experiment explicitly, signal N4 is assigned to the first 4Fe cluster in the TYKY subunit (position 5), and N5 to the all-cysteine ligated 4Fe cluster in the 75 kDa subunit (position 3). The implications of our assignment for the mechanisms of electron transfer and energy transduction by complex I are discussed.
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Affiliation(s)
- Maxie M. Roessler
- Center for Advanced Electron Spin Resonance, and
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom; and
| | - Martin S. King
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Alan J. Robinson
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom; and
| | | | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
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Cammack R, MacMillan F. Electron Magnetic Resonance of Iron–Sulfur Proteins in Electron-Transfer Chains: Resolving Complexity. METALS IN BIOLOGY 2010. [DOI: 10.1007/978-1-4419-1139-1_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Complex I (NADH:quinone oxidoreductase) is crucial to respiration in many aerobic organisms. In mitochondria, it oxidizes NADH (to regenerate NAD+ for the tricarboxylic acid cycle and fatty-acid oxidation), reduces ubiquinone (the electrons are ultimately used to reduce oxygen to water) and transports protons across the mitochondrial inner membrane (to produce and sustain the protonmotive force that supports ATP synthesis and transport processes). Complex I is also a major contributor to reactive oxygen species production in the cell. Understanding the mechanisms of energy transduction and reactive oxygen species production by complex I is not only a significant intellectual challenge, but also a prerequisite for understanding the roles of complex I in disease, and for the development of effective therapies. One approach to defining a complicated reaction mechanism is to break it down into manageable parts that can be tackled individually, before being recombined and integrated to produce the complete picture. Thus energy transduction by complex I comprises NADH oxidation by a flavin mononucleotide, intramolecular electron transfer from the flavin to bound quinone along a chain of iron–sulfur clusters, quinone reduction and proton translocation. More simply, molecular oxygen is reduced by the flavin, to form the reactive oxygen species superoxide and hydrogen peroxide. The present review summarizes and evaluates experimental data that pertain to the reaction mechanisms of complex I, and describes and discusses contemporary mechanistic hypotheses, proposals and models.
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Abstract
NADH:ubiquinone oxidoreductase (complex I) is an entry point for electrons into the respiratory chain in many eukaryotes. It couples NADH oxidation and ubiquinone reduction to proton translocation across the mitochondrial inner membrane. Because complex I deficiencies occur in a wide range of neuromuscular diseases, including Parkinson's disease, there is a clear need for model eukaryotic systems to facilitate structural, functional and mutational studies. In the present study, we describe the purification and characterization of the complexes I from two yeast species, Pichia pastoris and Pichia angusta. They are obligate aerobes which grow to very high cell densities on simple medium, as yeast-like, spheroidal cells. Both Pichia enzymes catalyse inhibitor-sensitive NADH:ubiquinone oxidoreduction, display EPR spectra which match closely to those from other eukaryotic complexes I, and show patterns characteristic of complex I in SDS/PAGE analysis. Mass spectrometry was used to identify several canonical complex I subunits. Purified P. pastoris complex I has a particularly high specific activity, and incorporating it into liposomes demonstrates that NADH oxidation is coupled to the generation of a protonmotive force. Interestingly, the rate of NADH-induced superoxide production by the Pichia enzymes is more than twice as high as that of the Bos taurus enzyme. Our results both resolve previous disagreement about whether Pichia species encode complex I, furthering understanding of the evolution of complex I within dikarya, and they provide two new, robust and highly active model systems for study of the structure and catalytic mechanism of eukaryotic complexes I.
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Abstract
Based on explicit definitions of biomolecular EPR spectroscopy and of the metallome, this tutorial review positions EPR in the field of metallomics as a unique method to study native, integrated systems of metallobiomolecular coordination complexes subject to external stimuli. The specific techniques of whole-system bioEPR spectroscopy are described and their historic, recent, and anticipated applications are discussed.
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Affiliation(s)
- Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands.
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King MS, Sharpley MS, Hirst J. Reduction of hydrophilic ubiquinones by the flavin in mitochondrial NADH:ubiquinone oxidoreductase (Complex I) and production of reactive oxygen species. Biochemistry 2009; 48:2053-62. [PMID: 19220002 PMCID: PMC2651670 DOI: 10.1021/bi802282h] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria is a complicated, energy-transducing, membrane-bound enzyme that contains 45 different subunits, a non-covalently bound flavin mononucleotide, and eight iron−sulfur clusters. The mechanisms of NADH oxidation and intramolecular electron transfer by complex I are gradually being defined, but the mechanism linking ubiquinone reduction to proton translocation remains unknown. Studies of ubiquinone reduction by isolated complex I are problematic because the extremely hydrophobic natural substrate, ubiquinone-10, must be substituted with a relatively hydrophilic analogue (such as ubiquinone-1). Hydrophilic ubiquinones are reduced by an additional, non-energy-transducing pathway (which is insensitive to inhibitors such as rotenone and piericidin A). Here, we show that inhibitor-insensitive ubiquinone reduction occurs by a ping-pong type mechanism, catalyzed by the flavin mononucleotide cofactor in the active site for NADH oxidation. Moreover, semiquinones produced at the flavin site initiate redox cycling reactions with molecular oxygen, producing superoxide radicals and hydrogen peroxide. The ubiquinone reactant is regenerated, so the NADH:Q reaction becomes superstoichiometric. Idebenone, an artificial ubiquinone showing promise in the treatment of Friedreich’s Ataxia, reacts at the flavin site. The factors which determine the balance of reactivity between the two sites of ubiquinone reduction (the energy-transducing site and the flavin site) and the implications for mechanistic studies of ubiquinone reduction by complex I are discussed. Finally, the possibility that the flavin site in complex I catalyzes redox cycling reactions with a wide range of compounds, some of which are important in pharmacology and toxicology, is discussed.
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Affiliation(s)
- Martin S King
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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Morris DG, Waters SM, McCarthy SD, Patton J, Earley B, Fitzpatrick R, Murphy JJ, Diskin MG, Kenny DA, Brass A, Wathes DC. Pleiotropic effects of negative energy balance in the postpartum dairy cow on splenic gene expression: repercussions for innate and adaptive immunity. Physiol Genomics 2009; 39:28-37. [PMID: 19567785 PMCID: PMC2747343 DOI: 10.1152/physiolgenomics.90394.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increased energy demands to support lactation, coupled with lowered feed intake capacity results in negative energy balance (NEB) and is typically characterized by extensive mobilization of body energy reserves in the early postpartum dairy cow. The catabolism of stored lipid leads to an increase in the systemic concentrations of nonesterified fatty acids (NEFA) and β-hydroxy butyrate (BHB). Oxidation of NEFA in the liver result in the increased production of reactive oxygen species and the onset of oxidative stress and can lead to disruption of normal metabolism and physiology. The immune system is depressed in the peripartum period and early lactation and dairy cows are therefore more vulnerable to bacterial infections causing mastitis and or endometritis at this time. A bovine Affymetrix oligonucleotide array was used to determine global gene expression in the spleen of dairy cows in the early postpartum period. Spleen tissue was removed post mortem from five severe NEB (SNEB) and five medium NEB (MNEB) cows 15 days postpartum. SNEB increased systemic concentrations of NEFA and BHB, and white blood cell and lymphocyte numbers were decreased in SNEB animals. A total of 545 genes were altered by SNEB. Network analysis using Ingenuity Pathway Analysis revealed that SNEB was associated with NRF2-mediated oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, natural killer cell signaling, p53 signaling, downregulation of IL-15, BCL-2, and IFN-γ; upregulation of BAX and CHOP and increased apoptosis with a potential negative impact on innate and adaptive immunity.
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Affiliation(s)
- D G Morris
- Teagasc, Mellows Campus, Athenry, County Galway, Ireland.
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