1
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Meisel JD, Miranda M, Skinner OS, Wiesenthal PP, Wellner SM, Jourdain AA, Ruvkun G, Mootha VK. Hypoxia and intra-complex genetic suppressors rescue complex I mutants by a shared mechanism. Cell 2024; 187:659-675.e18. [PMID: 38215760 PMCID: PMC10919891 DOI: 10.1016/j.cell.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 09/09/2023] [Accepted: 12/05/2023] [Indexed: 01/14/2024]
Abstract
The electron transport chain (ETC) of mitochondria, bacteria, and archaea couples electron flow to proton pumping and is adapted to diverse oxygen environments. Remarkably, in mice, neurological disease due to ETC complex I dysfunction is rescued by hypoxia through unknown mechanisms. Here, we show that hypoxia rescue and hyperoxia sensitivity of complex I deficiency are evolutionarily conserved to C. elegans and are specific to mutants that compromise the electron-conducting matrix arm. We show that hypoxia rescue does not involve the hypoxia-inducible factor pathway or attenuation of reactive oxygen species. To discover the mechanism, we use C. elegans genetic screens to identify suppressor mutations in the complex I accessory subunit NDUFA6/nuo-3 that phenocopy hypoxia rescue. We show that NDUFA6/nuo-3(G60D) or hypoxia directly restores complex I forward activity, with downstream rescue of ETC flux and, in some cases, complex I levels. Additional screens identify residues within the ubiquinone binding pocket as being required for the rescue by NDUFA6/nuo-3(G60D) or hypoxia. This reveals oxygen-sensitive coupling between an accessory subunit and the quinone binding pocket of complex I that can restore forward activity in the same manner as hypoxia.
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Affiliation(s)
- Joshua D Meisel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Maria Miranda
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Owen S Skinner
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Presli P Wiesenthal
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Sandra M Wellner
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Alexis A Jourdain
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Gary Ruvkun
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA.
| | - Vamsi K Mootha
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA.
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2
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Agip ANA, Chung I, Sanchez-Martinez A, Whitworth AJ, Hirst J. Cryo-EM structures of mitochondrial respiratory complex I from Drosophila melanogaster. eLife 2023; 12:e84424. [PMID: 36622099 PMCID: PMC9977279 DOI: 10.7554/elife.84424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
Respiratory complex I powers ATP synthesis by oxidative phosphorylation, exploiting the energy from NADH oxidation by ubiquinone to drive protons across an energy-transducing membrane. Drosophila melanogaster is a candidate model organism for complex I due to its high evolutionary conservation with the mammalian enzyme, well-developed genetic toolkit, and complex physiology for studies in specific cell types and tissues. Here, we isolate complex I from Drosophila and determine its structure, revealing a 43-subunit assembly with high structural homology to its 45-subunit mammalian counterpart, including a hitherto unknown homologue to subunit NDUFA3. The major conformational state of the Drosophila enzyme is the mammalian-type 'ready-to-go' active resting state, with a fully ordered and enclosed ubiquinone-binding site, but a subtly altered global conformation related to changes in subunit ND6. The mammalian-type 'deactive' pronounced resting state is not observed: in two minor states, the ubiquinone-binding site is unchanged, but a deactive-type π-bulge is present in ND6-TMH3. Our detailed structural knowledge of Drosophila complex I provides a foundation for new approaches to disentangle mechanisms of complex I catalysis and regulation in bioenergetics and physiology.
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Affiliation(s)
- Ahmed-Noor A Agip
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Injae Chung
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Alvaro Sanchez-Martinez
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Alexander J Whitworth
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical CampusCambridgeUnited Kingdom
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3
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Jarman OD, Hirst J. Membrane-domain mutations in respiratory complex I impede catalysis but do not uncouple proton pumping from ubiquinone reduction. PNAS Nexus 2022; 1:pgac276. [PMID: 36712358 PMCID: PMC9802314 DOI: 10.1093/pnasnexus/pgac276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/01/2022] [Indexed: 12/05/2022]
Abstract
Respiratory complex I [NADH:ubiquinone (UQ) oxidoreductase] captures the free energy released from NADH oxidation and UQ reduction to pump four protons across an energy-transducing membrane and power ATP synthesis. Mechanisms for long-range energy coupling in complex I have been proposed from structural data but not yet evaluated by robust biophysical and biochemical analyses. Here, we use the powerful bacterial model system Paracoccus denitrificans to investigate 14 mutations of key residues in the membrane-domain Nqo13/ND4 subunit, defining the rates and reversibility of catalysis and the number of protons pumped per NADH oxidized. We reveal new insights into the roles of highly conserved charged residues in lateral energy transduction, confirm the purely structural role of the Nqo12/ND5 transverse helix, and evaluate a proposed hydrated channel for proton uptake. Importantly, even when catalysis is compromised the enzyme remains strictly coupled (four protons are pumped per NADH oxidized), providing no evidence for escape cycles that circumvent blocked proton-pumping steps.
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Affiliation(s)
- Owen D Jarman
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
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4
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Burger N, James AM, Mulvey JF, Hoogewijs K, Ding S, Fearnley IM, Loureiro-López M, Norman AAI, Arndt S, Mottahedin A, Sauchanka O, Hartley RC, Krieg T, Murphy MP. ND3 Cys39 in complex I is exposed during mitochondrial respiration. Cell Chem Biol 2022; 29:636-649.e14. [PMID: 34739852 PMCID: PMC9076552 DOI: 10.1016/j.chembiol.2021.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/21/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Mammalian complex I can adopt catalytically active (A-) or deactive (D-) states. A defining feature of the reversible transition between these two defined states is thought to be exposure of the ND3 subunit Cys39 residue in the D-state and its occlusion in the A-state. As the catalytic A/D transition is important in health and disease, we set out to quantify it by measuring Cys39 exposure using isotopic labeling and mass spectrometry, in parallel with complex I NADH/CoQ oxidoreductase activity. To our surprise, we found significant Cys39 exposure during NADH/CoQ oxidoreductase activity. Furthermore, this activity was unaffected if Cys39 alkylation occurred during complex I-linked respiration. In contrast, alkylation of catalytically inactive complex I irreversibly blocked the reactivation of NADH/CoQ oxidoreductase activity by NADH. Thus, Cys39 of ND3 is exposed in complex I during mitochondrial respiration, with significant implications for our understanding of the A/D transition and the mechanism of complex I.
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Affiliation(s)
- Nils Burger
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Andrew M James
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - John F Mulvey
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Kurt Hoogewijs
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; The Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; Medical Research Council-Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Shujing Ding
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Ian M Fearnley
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Marta Loureiro-López
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | | | - Sabine Arndt
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Amin Mottahedin
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK; Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Olga Sauchanka
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | | | - Thomas Krieg
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Michael P Murphy
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
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5
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Vranas M, Wohlwend D, Qiu D, Gerhardt S, Trncik C, Pervaiz M, Ritter K, Steimle S, Randazzo A, Einsle O, Günther S, Jessen HJ, Kotlyar A, Friedrich T. Structural Basis for Inhibition of ROS-Producing Respiratory Complex I by NADH-OH. Angew Chem Int Ed Engl 2021; 60:27277-27281. [PMID: 34612584 PMCID: PMC9299107 DOI: 10.1002/anie.202112165] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Indexed: 11/09/2022]
Abstract
NADH:ubiquinone oxidoreductase, respiratory complex I, plays a central role in cellular energy metabolism. As a major source of reactive oxygen species (ROS) it affects ageing and mitochondrial dysfunction. The novel inhibitor NADH-OH specifically blocks NADH oxidation and ROS production by complex I in nanomolar concentrations. Attempts to elucidate its structure by NMR spectroscopy have failed. Here, by using X-ray crystallographic analysis, we report the structure of NADH-OH bound in the active site of a soluble fragment of complex I at 2.0 Å resolution. We have identified key amino acid residues that are specific and essential for binding NADH-OH. Furthermore, the structure sheds light on the specificity of NADH-OH towards the unique Rossmann-fold of complex I and indicates a regulatory role in mitochondrial ROS generation. In addition, NADH-OH acts as a lead-structure for the synthesis of a novel class of ROS suppressors.
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Affiliation(s)
- Marta Vranas
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany.,Magellan Biologics & Consulting, 4200-135, Porto, Portugal
| | - Daniel Wohlwend
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Danye Qiu
- Institute of Organic Chemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Stefan Gerhardt
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Christian Trncik
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Mehrosh Pervaiz
- Institute of Pharmazeutical Sciences, University of Freiburg, Germany
| | - Kevin Ritter
- Institute of Organic Chemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Stefan Steimle
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples, 80131, Napoli, Italy
| | - Oliver Einsle
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Stefan Günther
- Institute of Pharmazeutical Sciences, University of Freiburg, Germany
| | - Henning J Jessen
- Institute of Organic Chemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Alexander Kotlyar
- Department of Biochemistry and Molecular Biology, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Thorsten Friedrich
- Institute of Biochemistry, University of Freiburg, 79104, Freiburg, Germany
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6
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Whitehurst T, Howes O. The role of mitochondria in the pathophysiology of schizophrenia: A critical review of the evidence focusing on mitochondrial complex one. Neurosci Biobehav Rev 2021; 132:449-64. [PMID: 34864002 DOI: 10.1016/j.neubiorev.2021.11.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 12/30/2022]
Abstract
There has been increasing interest in the role of mitochondrial dysfunction in the pathophysiology of schizophrenia. Mitochondrial complex one (MCI) dysfunction may represent a mechanism linking bioenergetic impairment with the alterations in dopamine signalling, glutamatergic dysfunction, and oxidative stress found in the disorder. New lines of evidence from novel approaches make it timely to review evidence for mitochondrial involvement in schizophrenia, with a specific focus on MCI. The most consistent findings in schizophrenia relative to controls are reductions in expression of MCI subunits in post-mortem brain tissue (Cohen's d> 0.8); reductions in MCI function in post-mortem brains (d> 0.7); and reductions in neural glucose utilisation (d= 0.3 to 0.6). Antipsychotics may affect glucose utilisation, and, at least in vitro, affect MC1. The findings overall are consistent with MCI dysfunction in schizophrenia, but also highlight the need for in vivo studies to determine the link between MCI dysfunction and symptoms in patients. If new imaging tools confirm MCI dysfunction in the disease, this could pave the way for new treatments targeting this enzyme.
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7
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Jain S, Hu C, Kluza J, Ke W, Tian G, Giurgiu M, Bleilevens A, Campos AR, Charbono A, Stickeler E, Maurer J, Holinski-Feder E, Vaisburg A, Bureik M, Luo G, Marchetti P, Cheng Y, Wolf DA. Metabolic targeting of cancer by a ubiquinone uncompetitive inhibitor of mitochondrial complex I. Cell Chem Biol 2021; 29:436-450.e15. [PMID: 34852219 DOI: 10.1016/j.chembiol.2021.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/12/2021] [Accepted: 11/03/2021] [Indexed: 12/18/2022]
Abstract
SMIP004-7 is a small molecule inhibitor of mitochondrial respiration with selective in vivo anti-cancer activity through an as-yet unknown molecular target. We demonstrate here that SMIP004-7 targets drug-resistant cancer cells with stem-like features by inhibiting mitochondrial respiration complex I (NADH:ubiquinone oxidoreductase, complex I [CI]). Instead of affecting the quinone-binding site targeted by most CI inhibitors, SMIP004-7 and its cytochrome P450-dependent activated metabolite(s) have an uncompetitive mechanism of inhibition involving a distinct N-terminal region of catalytic subunit NDUFS2 that leads to rapid disassembly of CI. SMIP004-7 and an improved chemical analog selectively engage NDUFS2 in vivo to inhibit the growth of triple-negative breast cancer transplants, a response mediated at least in part by boosting CD4+ and CD8+ T cell-mediated immune surveillance. Thus, SMIP004-7 defines an emerging class of ubiquinone uncompetitive CI inhibitors for cell autonomous and microenvironmental metabolic targeting of mitochondrial respiration in cancer.
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Affiliation(s)
- Shashi Jain
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92024, USA
| | - Cheng Hu
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'An South Road, Xiamen, China
| | - Jerome Kluza
- Université de Lille, CNRS, Inserm, CHU Lille, Institut pour la Recherche sur le Cancer de Lille, UMR9020 - UMR-S 1277 - Canther - Cancer Heterogeneity, Plasticity and Resistance to Therapies, 59000 Lille, France
| | - Wei Ke
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'An South Road, Xiamen, China
| | - Guiyou Tian
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'An South Road, Xiamen, China
| | | | - Andreas Bleilevens
- Department of Obstetrics and Gynecology, University of Aachen, Aachen, Germany
| | | | - Adriana Charbono
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92024, USA
| | - Elmar Stickeler
- Department of Obstetrics and Gynecology, University of Aachen, Aachen, Germany
| | - Jochen Maurer
- Department of Obstetrics and Gynecology, University of Aachen, Aachen, Germany
| | - Elke Holinski-Feder
- MGZ Medical Genetics Center Munich, 80335 Munich, Germany; Department of Medicine IV, Campus Innenstadt, Klinikum der Universität München, Munich, Germany
| | - Arkadii Vaisburg
- Crocus Laboratories Inc., Montreal, QC, Canada; NuChem Sciences Inc., Montreal, QC, Canada
| | - Matthias Bureik
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Guangcheng Luo
- Department of Urology, Zhongshan Hospital, Xiamen University, Xiamen, China
| | - Philippe Marchetti
- Université de Lille, CNRS, Inserm, CHU Lille, Institut pour la Recherche sur le Cancer de Lille, UMR9020 - UMR-S 1277 - Canther - Cancer Heterogeneity, Plasticity and Resistance to Therapies, 59000 Lille, France; Centre de Bio-Pathologie, Banque de Tissus, CHU of Lille, Lille, France
| | - Yabin Cheng
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'An South Road, Xiamen, China.
| | - Dieter A Wolf
- State Key Laboratory of Stress Biology and Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiang'An South Road, Xiamen, China; MGZ Medical Genetics Center Munich, 80335 Munich, Germany; Department of Internal Medicine II, Klinikum rechts der Isar, Technical University Munich, 81675 Munich, Germany.
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8
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Hameedi MA, Grba DN, Richardson KH, Jones AJY, Song W, Roessler MM, Wright JJ, Hirst J. A conserved arginine residue is critical for stabilizing the N2 FeS cluster in mitochondrial complex I. J Biol Chem 2021; 296:100474. [PMID: 33640456 DOI: 10.1016/j.jbc.2021.100474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/18/2021] [Accepted: 02/24/2021] [Indexed: 11/22/2022] Open
Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase), the first enzyme of the electron-transport chain, captures the free energy released by NADH oxidation and ubiquinone reduction to translocate protons across an energy-transducing membrane and drive ATP synthesis during oxidative phosphorylation. The cofactor that transfers the electrons directly to ubiquinone is an iron–sulfur cluster (N2) located in the NDUFS2/NUCM subunit. A nearby arginine residue (R121), which forms part of the second coordination sphere of the N2 cluster, is known to be posttranslationally dimethylated but its functional and structural significance are not known. Here, we show that mutations of this arginine residue (R121M/K) abolish the quinone-reductase activity, concomitant with disappearance of the N2 signature from the electron paramagnetic resonance (EPR) spectrum. Analysis of the cryo-EM structure of NDUFS2-R121M complex I at 3.7 Å resolution identified the absence of the cubane N2 cluster as the cause of the dysfunction, within an otherwise intact enzyme. The mutation further induced localized disorder in nearby elements of the quinone-binding site, consistent with the close connections between the cluster and substrate-binding regions. Our results demonstrate that R121 is required for the formation and/or stability of the N2 cluster and highlight the importance of structural analyses for mechanistic interpretation of biochemical and spectroscopic data on complex I variants.
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9
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Di Luca A, Kaila VRI. Molecular strain in the active/deactive-transition modulates domain coupling in respiratory complex I. Biochim Biophys Acta Bioenerg 2021; 1862:148382. [PMID: 33513365 DOI: 10.1016/j.bbabio.2021.148382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/08/2021] [Accepted: 01/21/2021] [Indexed: 12/14/2022]
Abstract
Complex I functions as a primary redox-driven proton pump in aerobic respiratory chains, establishing a proton motive force that powers ATP synthesis and active transport. Recent cryo-electron microscopy (cryo-EM) experiments have resolved the mammalian complex I in the biomedically relevant active (A) and deactive (D) states (Zhu et al., 2016; Fiedorczuk et al., 2016; Agip et al., 2018 [1-3]) that could regulate enzyme turnover, but it still remains unclear how the conformational state and activity are linked. We show here how global motion along the A/D transition accumulates molecular strain at specific coupling regions important for both redox chemistry and proton pumping. Our data suggest that the A/D motion modulates force propagation pathways between the substrate-binding site and the proton pumping machinery that could alter electrostatic and conformational coupling across large distances. Our findings provide a molecular basis to understand how global protein dynamics can modulate the biological activity of large molecular complexes.
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Affiliation(s)
- Andrea Di Luca
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
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10
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Ji Y, Zhang J, Lu Y, Yi Q, Chen M, Xie S, Mao X, Xiao Y, Meng F, Zhang M, Yang R, Guan MX. Complex I mutations synergize to worsen the phenotypic expression of Leber's hereditary optic neuropathy. J Biol Chem 2020; 295:13224-13238. [PMID: 32723871 DOI: 10.1074/jbc.ra120.014603] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/24/2020] [Indexed: 12/15/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternal inheritance of eye disease because of the mitochondrial DNA (mtDNA) mutations. We previously discovered a 3866T>C mutation within the gene for the ND1 subunit of complex I as possibly amplifying disease progression for patients bearing the disease-causing 11778G>A mutation within the gene for the ND4 subunit of complex I. However, whether and how the ND1 mutation exacerbates the ND4 mutation were unknown. In this report, we showed that four Chinese families bearing both m.3866T>C and m.11778G>A mutations exhibited higher penetrances of LHON than 6 Chinese pedigrees carrying only the m.3866T>C mutation or families harboring only the m.11778G>A mutation. The protein structure analysis revealed that the m.3866T>C (I187T) and m.11778G>A (R340H) mutations destabilized the specific interactions with other residues of ND1 and ND4, thereby altering the structure and function of complex I. Cellular data obtained using cybrids, constructed by transferring mitochondria from the Chinese families into mtDNA-less (ρ°) cells, demonstrated that the mutations perturbed the stability, assembly, and activity of complex I, leading to changes in mitochondrial ATP levels and membrane potential and increasing the production of reactive oxygen species. These mitochondrial dysfunctions promoted the apoptotic sensitivity of cells and decreased mitophagy. Cybrids bearing only the m.3866T>C mutation displayed mild mitochondrial dysfunctions, whereas those harboring both m.3866T>C and m.11778G>A mutations exhibited greater mitochondrial dysfunctions. These suggested that the m.3866T>C mutation acted in synergy with the m.11778G>A mutation, aggravating mitochondrial dysfunctions and contributing to higher penetrance of LHON in these families carrying both mtDNA mutations.
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Affiliation(s)
- Yanchun Ji
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yuanyuan Lu
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Qiuzi Yi
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Mengquan Chen
- Department of Lab Medicine, Wenzhou Hospital of Traditional Chinese Medicine, Wenzhou, Zhejiang, China
| | - Shipeng Xie
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Xiaoting Mao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yun Xiao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feilong Meng
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Rulai Yang
- Department of Genetics and Metabolic Diseases, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Key Lab of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang, China; Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China.
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11
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Wright JJ, Fedor JG, Hirst J, Roessler MM. Using a chimeric respiratory chain and EPR spectroscopy to determine the origin of semiquinone species previously assigned to mitochondrial complex I. BMC Biol 2020; 18:54. [PMID: 32429970 PMCID: PMC7238650 DOI: 10.1186/s12915-020-00768-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/11/2020] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND For decades, semiquinone intermediates have been suggested to play an essential role in catalysis by one of the most enigmatic proton-pumping enzymes, respiratory complex I, and different mechanisms have been proposed on their basis. However, the difficulty in investigating complex I semiquinones, due to the many different enzymes embedded in the inner mitochondrial membrane, has resulted in an ambiguous picture and no consensus. RESULTS In this paper, we re-examine the highly debated origin of semiquinone species in mitochondrial membranes using a novel approach. Our combination of a semi-artificial chimeric respiratory chain with pulse EPR spectroscopy (HYSCORE) has enabled us to conclude, unambiguously and for the first time, that the majority of the semiquinones observed in mitochondrial membranes originate from complex III. We also identify a minor contribution from complex II. CONCLUSIONS We are unable to attribute any semiquinone signals unambiguously to complex I and, reconciling our observations with much of the previous literature, conclude that they are likely to have been misattributed to it. We note that, for this earlier work, the tools we have relied on here to deconvolute overlapping EPR signals were not available. Proposals for the mechanism of complex I based on the EPR signals of semiquinone species observed in mitochondrial membranes should thus be treated with caution until future work has succeeded in isolating any complex I semiquinone EPR spectroscopic signatures present.
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Affiliation(s)
- John J Wright
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Justin G Fedor
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Maxie M Roessler
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK.
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12
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Adjobo-Hermans MJW, de Haas R, Willems PHGM, Wojtala A, van Emst-de Vries SE, Wagenaars JA, van den Brand M, Rodenburg RJ, Smeitink JAM, Nijtmans LG, Sazanov LA, Wieckowski MR, Koopman WJH. NDUFS4 deletion triggers loss of NDUFA12 in Ndufs4 -/- mice and Leigh syndrome patients: A stabilizing role for NDUFAF2. Biochim Biophys Acta Bioenerg 2020; 1861:148213. [PMID: 32335026 DOI: 10.1016/j.bbabio.2020.148213] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 01/07/2023]
Abstract
Mutations in NDUFS4, which encodes an accessory subunit of mitochondrial oxidative phosphorylation (OXPHOS) complex I (CI), induce Leigh syndrome (LS). LS is a poorly understood pediatric disorder featuring brain-specific anomalies and early death. To study the LS pathomechanism, we here compared OXPHOS proteomes between various Ndufs4-/- mouse tissues. Ndufs4-/- animals displayed significantly lower CI subunit levels in brain/diaphragm relative to other tissues (liver/heart/kidney/skeletal muscle), whereas other OXPHOS subunit levels were not reduced. Absence of NDUFS4 induced near complete absence of the NDUFA12 accessory subunit, a 50% reduction in other CI subunit levels, and an increase in specific CI assembly factors. Among the latter, NDUFAF2 was most highly increased. Regarding NDUFS4, NDUFA12 and NDUFAF2, identical results were obtained in Ndufs4-/- mouse embryonic fibroblasts (MEFs) and NDUFS4-mutated LS patient cells. Ndufs4-/- MEFs contained active CI in situ but blue-native-PAGE highlighted that NDUFAF2 attached to an inactive CI subcomplex (CI-830) and inactive assemblies of higher MW. In NDUFA12-mutated LS patient cells, NDUFA12 absence did not reduce NDUFS4 levels but triggered NDUFAF2 association to active CI. BN-PAGE revealed no such association in LS patient fibroblasts with mutations in other CI subunit-encoding genes where NDUFAF2 was attached to CI-830 (NDUFS1, NDUFV1 mutation) or not detected (NDUFS7 mutation). Supported by enzymological and CI in silico structural analysis, we conclude that absence of NDUFS4 induces near complete absence of NDUFA12 but not vice versa, and that NDUFAF2 stabilizes active CI in Ndufs4-/- mice and LS patient cells, perhaps in concert with mitochondrial inner membrane lipids.
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Affiliation(s)
- Merel J W Adjobo-Hermans
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Ria de Haas
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | | | - Sjenet E van Emst-de Vries
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Jori A Wagenaars
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Mariel van den Brand
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Jan A M Smeitink
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Leo G Nijtmans
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | | | | | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands.
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13
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Skorupa P, Lindenstrauß U, Burschel S, Blumenscheit C, Friedrich T, Pinske C. The N-terminal domains of the paralogous HycE and NuoCD govern assembly of the respective formate hydrogenlyase and NADH dehydrogenase complexes. FEBS Open Bio 2020; 10:371-385. [PMID: 31925988 PMCID: PMC7050243 DOI: 10.1002/2211-5463.12787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 11/23/2022] Open
Abstract
Formate hydrogenlyase (FHL) is the main hydrogen-producing enzyme complex in enterobacteria. It converts formate to CO2 and H2 via a formate dehydrogenase and a [NiFe]-hydrogenase. FHL and complex I are evolutionarily related and share a common core architecture. However, complex I catalyses the fundamentally different electron transfer from NADH to quinone and pumps protons. The catalytic FHL subunit, HycE, resembles NuoCD of Escherichia coli complex I; a fusion of NuoC and NuoD present in other organisms. The C-terminal domain of HycE harbours the [NiFe]-active site and is similar to other hydrogenases, while this domain in NuoCD is involved in quinone binding. The N-terminal domains of these proteins do not bind cofactors and are not involved in electron transfer. As these N-terminal domains are separate proteins in some organisms, we removed them in E. coli and observed that both FHL and complex I activities were essentially absent. This was due to either a disturbed assembly or to complex instability. Replacing the N-terminal domain of HycE with a 180 amino acid E. coli NuoC protein fusion did not restore activity, indicating that the domains have complex-specific functions. A FHL complex in which the N- and C-terminal domains of HycE were physically separated still retained most of its FHL activity, while the separation of NuoCD abolished complex I activity completely. Only the FHL complex tolerates physical separation of the HycE domains. Together, the findings strongly suggest that the N-terminal domains of these proteins are key determinants in complex assembly.
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Affiliation(s)
- Philipp Skorupa
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
| | - Ute Lindenstrauß
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
| | - Sabrina Burschel
- Institute of Biochemistry/Molecular BioenergeticsAlbert‐Ludwigs‐University FreiburgGermany
| | | | - Thorsten Friedrich
- Institute of Biochemistry/Molecular BioenergeticsAlbert‐Ludwigs‐University FreiburgGermany
| | - Constanze Pinske
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
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14
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Kaila VRI. Long-range proton-coupled electron transfer in biological energy conversion: towards mechanistic understanding of respiratory complex I. J R Soc Interface 2019; 15:rsif.2017.0916. [PMID: 29643224 PMCID: PMC5938582 DOI: 10.1098/rsif.2017.0916] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/13/2018] [Indexed: 12/20/2022] Open
Abstract
Biological energy conversion is driven by efficient enzymes that capture, store and transfer protons and electrons across large distances. Recent advances in structural biology have provided atomic-scale blueprints of these types of remarkable molecular machinery, which together with biochemical, biophysical and computational experiments allow us to derive detailed energy transduction mechanisms for the first time. Here, I present one of the most intricate and least understood types of biological energy conversion machinery, the respiratory complex I, and how its redox-driven proton-pump catalyses charge transfer across approximately 300 Å distances. After discussing the functional elements of complex I, a putative mechanistic model for its action-at-a-distance effect is presented, and functional parallels are drawn to other redox- and light-driven ion pumps.
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Affiliation(s)
- Ville R I Kaila
- Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, Garching, Germany
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15
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Rhooms SK, Murari A, Goparaju NSV, Vilanueva M, Owusu-Ansah E. Insights from Drosophila on mitochondrial complex I. Cell Mol Life Sci 2020; 77:607-18. [PMID: 31485716 DOI: 10.1007/s00018-019-03293-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/08/2019] [Accepted: 08/28/2019] [Indexed: 12/26/2022]
Abstract
NADH:ubiquinone oxidoreductase, more commonly referred to as mitochondrial complex I (CI), is the largest discrete enzyme of the oxidative phosphorylation system (OXPHOS). It is localized to the mitochondrial inner membrane. CI oxidizes NADH generated from the tricarboxylic acid cycle to NAD+, in a series of redox reactions that culminates in the reduction of ubiquinone, and the transport of protons from the matrix across the inner membrane to the intermembrane space. The resulting proton-motive force is consumed by ATP synthase to generate ATP, or harnessed to transport ions, metabolites and proteins into the mitochondrion. CI is also a major source of reactive oxygen species. Accordingly, impaired CI function has been associated with a host of chronic metabolic and degenerative disorders such as diabetes, cardiomyopathy, Parkinson's disease (PD) and Leigh syndrome. Studies on Drosophila have contributed to our understanding of the multiple roles of CI in bioenergetics and organismal physiology. Here, we explore and discuss some of the studies on Drosophila that have informed our understanding of this complex and conclude with some of the open questions about CI that can be resolved by studies on Drosophila.
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16
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Chen Q, Thompson J, Hu Y, Dean J, Lesnefsky EJ. Inhibition of the ubiquitous calpains protects complex I activity and enables improved mitophagy in the heart following ischemia-reperfusion. Am J Physiol Cell Physiol 2019; 317:C910-C921. [PMID: 31411917 DOI: 10.1152/ajpcell.00190.2019] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Activation of calpain 1 (CPN1) and calpain 2 (CPN2) contributes to cardiac injury during ischemia (ISC) and reperfusion (REP). Complex I activity is decreased in heart mitochondria following ISC-REP. CPN1 and CPN2 are ubiquitous calpains that exist in both cytosol (cs)-CPN1 and 2 and mitochondria (mit)-CPN1 and 2. Recent work shows that the complex I subunit (NDUFS7) is a potential substrate of the mit-CPN1. We asked whether ISC-REP led to decreased complex I activity via proteolysis of the NDUFS7 subunit via activation of mit-CPN1 and -2. Activation of cs-CPN1 and -2 decreases mitophagy in hepatocytes following ISC-REP. We asked whether activation of cs-CPN1 and -2 impaired mitophagy in the heart following ISC-REP. Buffer-perfused rat hearts underwent 25 min of global ISC and 30 min of REP. MDL-28170 (MDL; 10 µM) was used to inhibit CPN1 and -2. Cytosol, subsarcolemmal mitochondria (SSM), and interfibrillar mitochondria (IFM) were isolated at the end of heart perfusion. Cardiac ISC-REP led to decreased complex I activity with a decrease in the content of NDUFS7 in both SSM and IFM. ISC-REP also resulted in a decrease in cytosolic beclin-1 content, a key component of the autophagy pathway required to form autophagosomes. MDL treatment protected the contents of cytosolic beclin-1 and mitochondrial NDUFS7 in hearts following ISC-REP. These results support that activation of both cytosolic and mitochondrial calpains impairs mitochondria during cardiac ISC-REP. Mitochondria-localized calpains impair complex I via cleavage of a key subunit. Activation of cytosolic calpains contributes to mitochondrial dysfunction by impairing removal of the impaired mitochondria through depletion of a key component of the mitophagy process.
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Affiliation(s)
- Qun Chen
- Department of Medicine, Division of Cardiology, Virginia Commonwealth University, Richmond, Virginia
| | - Jeremy Thompson
- Department of Medicine, Division of Cardiology, Virginia Commonwealth University, Richmond, Virginia
| | - Ying Hu
- Department of Medicine, Division of Cardiology, Virginia Commonwealth University, Richmond, Virginia
| | - Joseph Dean
- Department of Medicine, Division of Cardiology, Virginia Commonwealth University, Richmond, Virginia
| | - Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Virginia Commonwealth University, Richmond, Virginia.,Department of Biochemistry and Molecular Biology Virginia Commonwealth University, Richmond, Virginia.,Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia.,McGuire Department of Veterans Affairs Medical Center, Richmond, Virginia
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17
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Abstract
Single-particle electron cryomicroscopy (cryo-EM) has led to a revolution in structural work on mammalian respiratory complex I. Complex I (mitochondrial NADH:ubiquinone oxidoreductase), a membrane-bound redox-driven proton pump, is one of the largest and most complicated enzymes in the mammalian cell. Rapid progress, following the first 5-Å resolution data on bovine complex I in 2014, has led to a model for mouse complex I at 3.3-Å resolution that contains 96% of the 8,518 residues and to the identification of different particle classes, some of which are assigned to biochemically defined states. Factors that helped improve resolution, including improvements to biochemistry, cryo-EM grid preparation, data collection strategy, and image processing, are discussed. Together with recent structural data from an ancient relative, membrane-bound hydrogenase, cryo-EM on mammalian complex I has provided new insights into the proton-pumping machinery and a foundation for understanding the enzyme's catalytic mechanism.
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Affiliation(s)
- Ahmed-Noor A Agip
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom; , , ,
| | - James N Blaza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom; , , , .,Current affiliation: York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Justin G Fedor
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom; , , ,
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom; , , ,
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18
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Warnau J, Sharma V, Gamiz-Hernandez AP, Di Luca A, Haapanen O, Vattulainen I, Wikström M, Hummer G, Kaila VRI. Redox-coupled quinone dynamics in the respiratory complex I. Proc Natl Acad Sci U S A 2018; 115:E8413-20. [PMID: 30120126 DOI: 10.1073/pnas.1805468115] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Complex I couples the free energy released from quinone (Q) reduction to pump protons across the biological membrane in the respiratory chains of mitochondria and many bacteria. The Q reduction site is separated by a large distance from the proton-pumping membrane domain. To address the molecular mechanism of this long-range proton-electron coupling, we perform here full atomistic molecular dynamics simulations, free energy calculations, and continuum electrostatics calculations on complex I from Thermus thermophilus We show that the dynamics of Q is redox-state-dependent, and that quinol, QH2, moves out of its reduction site and into a site in the Q tunnel that is occupied by a Q analog in a crystal structure of Yarrowia lipolytica We also identify a second Q-binding site near the opening of the Q tunnel in the membrane domain, where the Q headgroup forms strong interactions with a cluster of aromatic and charged residues, while the Q tail resides in the lipid membrane. We estimate the effective diffusion coefficient of Q in the tunnel, and in turn the characteristic time for Q to reach the active site and for QH2 to escape to the membrane. Our simulations show that Q moves along the Q tunnel in a redox-state-dependent manner, with distinct binding sites formed by conserved residue clusters. The motion of Q to these binding sites is proposed to be coupled to the proton-pumping machinery in complex I.
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19
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Ozay EI, Sherman HL, Mello V, Trombley G, Lerman A, Tew GN, Yadava N, Minter LM. Rotenone Treatment Reveals a Role for Electron Transport Complex I in the Subcellular Localization of Key Transcriptional Regulators During T Helper Cell Differentiation. Front Immunol 2018; 9:1284. [PMID: 29930555 PMCID: PMC5999735 DOI: 10.3389/fimmu.2018.01284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/22/2018] [Indexed: 01/19/2023] Open
Abstract
Recent advances in our understanding of tumor cell mitochondrial metabolism suggest it may be an attractive therapeutic target. Mitochondria are central hubs of metabolism that provide energy during the differentiation and maintenance of immune cell phenotypes. Mitochondrial membranes harbor several enzyme complexes that are involved in the process of oxidative phosphorylation, which takes place during energy production. Data suggest that, among these enzyme complexes, deficiencies in electron transport complex I may differentially affect immune responses and may contribute to the pathophysiology of several immunological conditions. Once activated by T cell receptor signaling, along with co-stimulation through CD28, CD4 T cells utilize mitochondrial energy to differentiate into distinct T helper (Th) subsets. T cell signaling activates Notch1, which is cleaved from the plasma membrane to generate its intracellular form (N1ICD). In the presence of specific cytokines, Notch1 regulates gene transcription related to cell fate to modulate CD4 Th type 1, Th2, Th17, and induced regulatory T cell (iTreg) differentiation. The process of differentiating into any of these subsets requires metabolic energy, provided by the mitochondria. We hypothesized that the requirement for mitochondrial metabolism varies between different Th subsets and may intersect with Notch1 signaling. We used the organic pesticide rotenone, a well-described complex I inhibitor, to assess how compromised mitochondrial integrity impacts CD4 T cell differentiation into Th1, Th2, Th17, and iTreg cells. We also investigated how Notch1 localization and downstream transcriptional capabilities regulation may be altered in each subset following rotenone treatment. Our data suggest that mitochondrial integrity impacts each of these Th subsets differently, through its influence on Notch1 subcellular localization. Our work further supports the notion that altered immune responses can result from complex I inhibition. Therefore, understanding how mitochondrial inhibitors affect immune responses may help to inform therapeutic approaches to cancer treatment.
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Affiliation(s)
- Emrah Ilker Ozay
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States
| | - Heather L Sherman
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States
| | - Victoria Mello
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, United States
| | - Grace Trombley
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Adam Lerman
- Department of Microbiology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Gregory N Tew
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States.,Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, United States.,Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, United States
| | - Nagendra Yadava
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States.,Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States.,Pioneer Valley Life Sciences Institute, Springfield, MA, United States
| | - Lisa M Minter
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States.,Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, United States
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20
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Di Luca A, Mühlbauer ME, Saura P, Kaila VRI. How inter-subunit contacts in the membrane domain of complex I affect proton transfer energetics. Biochim Biophys Acta Bioenerg 2018; 1859:734-741. [PMID: 29883589 DOI: 10.1016/j.bbabio.2018.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/08/2018] [Accepted: 06/02/2018] [Indexed: 10/14/2022]
Abstract
The respiratory complex I is a redox-driven proton pump that employs the free energy released from quinone reduction to pump protons across its complete ca. 200 Å wide membrane domain. Despite recently resolved structures and molecular simulations, the exact mechanism for the proton transport process remains unclear. Here we combine large-scale molecular simulations with quantum chemical density functional theory (DFT) models to study how contacts between neighboring antiporter-like subunits in the membrane domain of complex I affect the proton transfer energetics. Our combined results suggest that opening of conserved Lys/Glu ion pairs within each antiporter-like subunit modulates the barrier for the lateral proton transfer reactions. Our work provides a mechanistic suggestion for key coupling effects in the long-range force propagation process of complex I.
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Affiliation(s)
- Andrea Di Luca
- Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany
| | - Max E Mühlbauer
- Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany
| | - Patricia Saura
- Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany
| | - Ville R I Kaila
- Department Chemie, Technische Universität München, Lichtenbergstr. 4, Garching, D-85747, Germany.
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21
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Maclean AE, Hertle AP, Ligas J, Bock R, Balk J, Meyer EH. Absence of Complex I Is Associated with Diminished Respiratory Chain Function in European Mistletoe. Curr Biol 2018; 28:1614-1619.e3. [PMID: 29731304 DOI: 10.1016/j.cub.2018.03.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/01/2018] [Accepted: 03/16/2018] [Indexed: 12/18/2022]
Abstract
Parasitism is a life history strategy found across all domains of life whereby nutrition is obtained from a host. It is often associated with reductive evolution of the genome, including loss of genes from the organellar genomes [1, 2]. In some unicellular parasites, the mitochondrial genome (mitogenome) has been lost entirely, with far-reaching consequences for the physiology of the organism [3, 4]. Recently, mitogenome sequences of several species of the hemiparasitic plant mistletoe (Viscum sp.) have been reported [5, 6], revealing a striking loss of genes not seen in any other multicellular eukaryotes. In particular, the nad genes encoding subunits of respiratory complex I are all absent and other protein-coding genes are also lost or highly diverged in sequence, raising the question what remains of the respiratory complexes and mitochondrial functions. Here we show that oxidative phosphorylation (OXPHOS) in European mistletoe, Viscum album, is highly diminished. Complex I activity and protein subunits of complex I could not be detected. The levels of complex IV and ATP synthase were at least 5-fold lower than in the non-parasitic model plant Arabidopsis thaliana, whereas alternative dehydrogenases and oxidases were higher in abundance. Carbon flux analysis indicates that cytosolic reactions including glycolysis are greater contributors to ATP synthesis than the mitochondrial tricarboxylic acid (TCA) cycle. Our results describe the extreme adjustments in mitochondrial functions of the first reported multicellular eukaryote without complex I.
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22
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Blaza JN, Vinothkumar KR, Hirst J. Structure of the Deactive State of Mammalian Respiratory Complex I. Structure 2018; 26:312-319.e3. [PMID: 29395787 PMCID: PMC5807054 DOI: 10.1016/j.str.2017.12.014] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/03/2017] [Accepted: 12/27/2017] [Indexed: 12/20/2022]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) is central to energy metabolism in mammalian mitochondria. It couples NADH oxidation by ubiquinone to proton transport across the energy-conserving inner membrane, catalyzing respiration and driving ATP synthesis. In the absence of substrates, active complex I gradually enters a pronounced resting or deactive state. The active-deactive transition occurs during ischemia and is crucial for controlling how respiration recovers upon reperfusion. Here, we set a highly active preparation of Bos taurus complex I into the biochemically defined deactive state, and used single-particle electron cryomicroscopy to determine its structure to 4.1 Å resolution. We show that the deactive state arises when critical structural elements that form the ubiquinone-binding site become disordered, and we propose reactivation is induced when substrate binding to the NADH-reduced enzyme templates their reordering. Our structure both rationalizes biochemical data on the deactive state and offers new insights into its physiological and cellular roles. Preparation of mammalian complex I in the deactive state that forms during ischemia The structure of the deactive state determined using electron cryomicroscopy Improved particle densities and orientations obtained using PEGylated gold grids Localized unfolding around the quinone-binding site in the deactive state
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Affiliation(s)
- James N Blaza
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Kutti R Vinothkumar
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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Pryde KR, Taanman JW, Schapira AH. A LON-ClpP Proteolytic Axis Degrades Complex I to Extinguish ROS Production in Depolarized Mitochondria. Cell Rep 2017; 17:2522-2531. [PMID: 27926857 PMCID: PMC5177631 DOI: 10.1016/j.celrep.2016.11.027] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 09/28/2016] [Accepted: 11/03/2016] [Indexed: 10/27/2022] Open
Abstract
Mitochondrial dysfunction is implicated in numerous neurodegenerative disorders and in Parkinson's disease (PD) in particular. PINK1 and Parkin gene mutations are causes of autosomal recessive PD, and these respective proteins function cooperatively to degrade depolarized mitochondria (mitophagy). It is widely assumed that impaired mitophagy causes PD, as toxic reactive oxygen species (ROS)-producing mitochondria accumulate and progressively drive neurodegeneration. Instead, we report that a LON-ClpP proteolytic quality control axis extinguishes ROS in depolarized mitochondria by degrading the complex I ROS-generating domain. Complex I deficiency has also been identified in PD brain, and our study provides a compelling non-genetic mechanistic rationale to explain this observation: intact complex I depletes if mitochondrial bioenergetic capacity is robustly attenuated.
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Affiliation(s)
- Kenneth Robert Pryde
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London WC1E 6BT, UK.
| | - Jan Willem Taanman
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London WC1E 6BT, UK
| | - Anthony Henry Schapira
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London WC1E 6BT, UK
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Fedor JG, Jones AJY, Di Luca A, Kaila VRI, Hirst J. Correlating kinetic and structural data on ubiquinone binding and reduction by respiratory complex I. Proc Natl Acad Sci U S A 2017; 114:12737-42. [PMID: 29133414 DOI: 10.1073/pnas.1714074114] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase), one of the largest membrane-bound enzymes in mammalian cells, powers ATP synthesis by using the energy from electron transfer from NADH to ubiquinone-10 to drive protons across the energy-transducing mitochondrial inner membrane. Ubiquinone-10 is extremely hydrophobic, but in complex I the binding site for its redox-active quinone headgroup is ∼20 Å above the membrane surface. Structural data suggest it accesses the site by a narrow channel, long enough to accommodate almost all of its ∼50-Å isoprenoid chain. However, how ubiquinone/ubiquinol exchange occurs on catalytically relevant timescales, and whether binding/dissociation events are involved in coupling electron transfer to proton translocation, are unknown. Here, we use proteoliposomes containing complex I, together with a quinol oxidase, to determine the kinetics of complex I catalysis with ubiquinones of varying isoprenoid chain length, from 1 to 10 units. We interpret our results using structural data, which show the hydrophobic channel is interrupted by a highly charged region at isoprenoids 4-7. We demonstrate that ubiquinol-10 dissociation is not rate determining and deduce that ubiquinone-10 has both the highest binding affinity and the fastest binding rate. We propose that the charged region and chain directionality assist product dissociation, and that isoprenoid stepping ensures short transit times. These properties of the channel do not benefit the exhange of short-chain quinones, for which product dissociation may become rate limiting. Thus, we discuss how the long channel does not hinder catalysis under physiological conditions and the possible roles of ubiquinone/ubiquinol binding/dissociation in energy conversion.
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25
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Abstract
Complex I functions as the initial electron acceptor in aerobic respiratory chains of most organisms. This gigantic redox-driven enzyme employs the energy from quinone reduction to pump protons across its complete approximately 200-Å membrane domain, thermodynamically driving synthesis of ATP. Despite recently resolved structures from several species, the molecular mechanism by which complex I catalyzes this long-range proton-coupled electron transfer process, however, still remains unclear. We perform here large-scale classical and quantum molecular simulations to study the function of the proton pump in complex I from Thermus thermophilus The simulations suggest that proton channels are established at symmetry-related locations in four subunits of the membrane domain. The channels open up by formation of quasi one-dimensional water chains that are sensitive to the protonation states of buried residues at structurally conserved broken helix elements. Our combined data provide mechanistic insight into long-range coupling effects and predictions for site-directed mutagenesis experiments.
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26
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Bridges HR, Mohammed K, Harbour ME, Hirst J. Subunit NDUFV3 is present in two distinct isoforms in mammalian complex I. Biochim Biophys Acta Bioenerg 2017; 1858:197-207. [PMID: 27940020 PMCID: PMC5293009 DOI: 10.1016/j.bbabio.2016.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 01/10/2023]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) is the first enzyme of the electron transport chain in mammalian mitochondria. Extensive proteomic and structural analyses of complex I from Bos taurus heart mitochondria have shown it comprises 45 subunits encoded on both the nuclear and mitochondrial genomes; 44 of them are different and one is present in two copies. The bovine heart enzyme has provided a model for studying the composition of complex I in other mammalian species, including humans, but the possibility of additional subunits or isoforms in other species or tissues has not been explored. Here, we describe characterization of the complexes I purified from five rat tissues and from a rat hepatoma cell line. We identify a~50kDa isoform of subunit NDUFV3, for which the canonical isoform is only ~10kDa in size. We combine LC-MS and MALDI-TOF mass spectrometry data from two different purification methods (chromatography and immuno-purification) with information from blue native PAGE analyses to show the long isoform is present in the mature complex, but at substoichiometric levels. It is also present in complex I in cultured human cells. We describe evidence that the long isoform is more abundant in both the mitochondria and purified complexes from brain (relative to in heart, liver, kidney and skeletal muscle) and more abundant still in complex I in cultured cells. We propose that the long 50kDa isoform competes with its canonical 10kDa counterpart for a common binding site on the flavoprotein domain of complex I.
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Affiliation(s)
- Hannah R Bridges
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Khairunnisa Mohammed
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Michael E Harbour
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, U. K..
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27
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Kahlhöfer F, Kmita K, Wittig I, Zwicker K, Zickermann V. Accessory subunit NUYM (NDUFS4) is required for stability of the electron input module and activity of mitochondrial complex I. Biochim Biophys Acta Bioenerg 2016; 1858:175-181. [PMID: 27871794 DOI: 10.1016/j.bbabio.2016.11.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 11/18/2022]
Abstract
Mitochondrial complex I is an intricate 1MDa membrane protein complex with a central role in aerobic energy metabolism. The minimal form of complex I consists of fourteen central subunits that are conserved from bacteria to man. In addition, eukaryotic complex I comprises some 30 accessory subunits of largely unknown function. The gene for the accessory NDUFS4 subunit of human complex I is a hot spot for fatal pathogenic mutations in humans. We have deleted the gene for the orthologous NUYM subunit in the aerobic yeast Yarrowia lipolytica, an established model system to study eukaryotic complex I and complex I linked diseases. We observed assembly of complex I which lacked only subunit NUYM and retained weak interaction with assembly factor N7BML (human NDUFAF2). Absence of NUYM caused distortion of iron sulfur clusters of the electron input domain leading to decreased complex I activity and increased release of reactive oxygen species. We conclude that NUYM has an important stabilizing function for the electron input module of complex I and is essential for proper complex I function.
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Affiliation(s)
- Flora Kahlhöfer
- Structural Bioenergetics Group, Institute of Biochemistry II, Medical School, Goethe-University Frankfurt am Main, Germany
| | - Katarzyna Kmita
- Structural Bioenergetics Group, Institute of Biochemistry II, Medical School, Goethe-University Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics, Institute of Biochemistry I, Medical School, Goethe-University Frankfurt am Main, Germany; Cluster of Excellence Frankfurt "Macromolecular Complexes", Goethe-University Frankfurt am Main, Germany
| | - Klaus Zwicker
- Institute of Biochemistry I, Medical School, Goethe University Frankfurt am Main, Germany
| | - Volker Zickermann
- Structural Bioenergetics Group, Institute of Biochemistry II, Medical School, Goethe-University Frankfurt am Main, Germany; Cluster of Excellence Frankfurt "Macromolecular Complexes", Goethe-University Frankfurt am Main, Germany.
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28
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Surve SV, Jensen BC, Heestand M, Mazet M, Smith TK, Bringaud F, Parsons M, Schnaufer A. NADH dehydrogenase of Trypanosoma brucei is important for efficient acetate production in bloodstream forms. Mol Biochem Parasitol 2016; 211:57-61. [PMID: 27717801 PMCID: PMC5225879 DOI: 10.1016/j.molbiopara.2016.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/29/2016] [Accepted: 10/03/2016] [Indexed: 11/29/2022]
Abstract
Various genetic mutants of NDH2 were created in bloodstream form Trypanosoma brucei. NDH2 null mutants showed a substantial reduction in growth. NDH2 ablation in a complex I deficient background led to severe growth restriction. Upon prolonged culture, parasites partially compensated for NDH2 deficiency. Loss of NDH2 led to reduced acetate, potentially contributing to the growth defect.
In the slender bloodstream form, Trypanosoma brucei mitochondria are repressed for many functions. Multiple components of mitochondrial complex I, NADH:ubiquinone oxidoreductase, are expressed in this stage, but electron transfer through complex I is not essential. Here we investigate the role of the parasite’s second NADH:ubiquinone oxidoreductase, NDH2, which is composed of a single subunit that also localizes to the mitochondrion. While inducible knockdown of NDH2 had a modest growth effect in bloodstream forms, NDH2 null mutants, as well as inducible knockdowns in a complex I deficient background, showed a greater reduction in growth. Altering the NAD+/NADH balance would affect numerous processes directly and indirectly, including acetate production. Indeed, loss of NDH2 led to reduced levels of acetate, which is required for several essential pathways in bloodstream form T. brucei and which may have contributed to the observed growth defect. In conclusion our study shows that NDH2 is important, but not essential, in proliferating bloodstream forms of T. brucei, arguing that the mitochondrial NAD+/NADH balance is important in this stage, even though the mitochondrion itself is not actively engaged in the generation of ATP.
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Affiliation(s)
- Sachin V Surve
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Bryan C Jensen
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Meredith Heestand
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA
| | - Muriel Mazet
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université de Bordeaux, CNRS, Bordeaux, France
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
| | - Frédéric Bringaud
- Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), UMR5536, Université de Bordeaux, CNRS, Bordeaux, France
| | - Marilyn Parsons
- Center for Infectious Disease Research (Formerly Seattle Biomedical Research Institute), 307 Westlake Ave. N., Seattle, WA, 98109, USA; Dept. of Global Health, University of Washington, Seattle, WA, 98195, USA.
| | - Achim Schnaufer
- Institute of Immunology & Infection Research and Centre of Immunity, Infection & Evolution, The University of Edinburgh, Edinburgh, EH9 3FL, United Kingdom.
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29
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D'Imprima E, Mills DJ, Parey K, Brandt U, Kühlbrandt W, Zickermann V, Vonck J. Cryo-EM structure of respiratory complex I reveals a link to mitochondrial sulfur metabolism. Biochim Biophys Acta 2016; 1857:1935-42. [PMID: 27693469 DOI: 10.1016/j.bbabio.2016.09.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/22/2016] [Accepted: 09/29/2016] [Indexed: 12/17/2022]
Abstract
Mitochondrial complex I is a 1MDa membrane protein complex with a central role in aerobic energy metabolism. The bioenergetic core functions are executed by 14 central subunits that are conserved from bacteria to man. Despite recent progress in structure determination, our understanding of the function of the ~30 accessory subunits associated with the mitochondrial complex is still limited. We have investigated the structure of complex I from the aerobic yeast Yarrowia lipolytica by cryo-electron microscopy. Our density map at 7.9Å resolution closely matches the 3.6-3.9Å X-ray structure of the Yarrowia lipolytica complex. However, the cryo-EM map indicated an additional subunit on the side of the matrix arm above the membrane surface, pointing away from the membrane arm. The density, which is not present in any previously described complex I structure and occurs in about 20 % of the particles, was identified as the accessory sulfur transferase subunit ST1. The Yarrowia lipolytica complex I preparation is active in generating H2S from the cysteine derivative 3-mercaptopyruvate, catalyzed by ST1. We thus provide evidence for a link between respiratory complex I and mitochondrial sulfur metabolism.
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30
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Bridges HR, Sirviö VA, Agip ANA, Hirst J. Molecular features of biguanides required for targeting of mitochondrial respiratory complex I and activation of AMP-kinase. BMC Biol 2016; 14:65. [PMID: 27506389 PMCID: PMC4977651 DOI: 10.1186/s12915-016-0287-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/22/2016] [Indexed: 01/19/2023] Open
Abstract
Background The biguanides are a family of drugs with diverse clinical applications. Metformin, a widely used anti-hyperglycemic biguanide, suppresses mitochondrial respiration by inhibiting respiratory complex I. Phenformin, a related anti-hyperglycemic biguanide, also inhibits respiration, but proguanil, which is widely used for the prevention of malaria, does not. The molecular structures of phenformin and proguanil are closely related and both inhibit isolated complex I. Proguanil does not inhibit respiration in cells and mitochondria because it is unable to access complex I. The molecular features that determine which biguanides accumulate in mitochondria, enabling them to inhibit complex I in vivo, are not known. Results Here, a family of seven biguanides are used to reveal the molecular features that determine why phenformin enters mitochondria and inhibits respiration whereas proguanil does not. All seven biguanides inhibit isolated complex I, but only four of them inhibit respiration in cells and mitochondria. Direct conjugation of a phenyl group and bis-substitution of the biguanide moiety prevent uptake into mitochondria, irrespective of the compound hydrophobicity. This high selectivity suggests that biguanide uptake into mitochondria is protein mediated, and is not by passive diffusion. Only those biguanides that enter mitochondria and inhibit complex I activate AMP kinase, strengthening links between complex I and the downstream effects of biguanide treatments. Conclusions Biguanides inhibit mitochondrial complex I, but specific molecular features control the uptake of substituted biguanides into mitochondria, so only some biguanides inhibit mitochondrial respiration in vivo. Biguanides with restricted intracellular access may be used to determine physiologically relevant targets of biguanide action, and for the rational design of substituted biguanides for diverse clinical applications. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0287-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Ville A Sirviö
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Ahmed-Noor A Agip
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK.
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31
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Hanazono Y, Takeda K, Miki K. Characterization of the Nqo5 subunit of bacterial complex I in the isolated state. FEBS Open Bio 2016; 6:687-95. [PMID: 27398308 PMCID: PMC4932448 DOI: 10.1002/2211-5463.12070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 11/09/2022] Open
Abstract
The subunits that comprise bacterial complex I (NADH:ubiquinone oxidoreductase) are also found in more complicated mitochondrial enzymes in eukaryotic organisms. Although the Nqo5 subunit is one of these conserved components and important for the formation of complex, it has been little studied. Here, we report structure analyses of isolated Nqo5 from Thermus thermophilus. Biochemical studies indicated that the C-terminal region following the 30-Kd subunit motif is disordered in the isolated state, while the remaining portion is already folded. Crystallographic studies of a trypsin-resistant fragment revealed detailed structural differences in the folded domain between the isolated and complexed states.
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Affiliation(s)
- Yuya Hanazono
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto Japan
| | - Kazuki Takeda
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto Japan; RIKEN SPring-8 Center at Harima Institute Sayo Hyogo Japan
| | - Kunio Miki
- Department of Chemistry Graduate School of Science Kyoto University Sakyo-ku Kyoto Japan; RIKEN SPring-8 Center at Harima Institute Sayo Hyogo Japan
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32
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Belevich N, Verkhovskaya M. Resting state of respiratory Complex I from Escherichia coli. FEBS Lett 2016; 590:1570-5. [PMID: 27148945 DOI: 10.1002/1873-3468.12199] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/02/2016] [Accepted: 05/02/2016] [Indexed: 12/31/2022]
Abstract
Respiratory Complex I from Escherichia coli may exist in two states, resting (R) and active (A). The conversion from the R- to A-forms occurs spontaneously upon turnover. The fast resting-to-active (R/A) transition of membrane-bound and purified Complex I was studied with the stopped-flow technique by following NADH oxidation either by absorption decay at 340 nm or using the fluorescent pH indicator, trisodium 8-hydroxypyrene-1,3,6-trisulfonate (pyranine). The R/A transition of Complex I from E. coli occurs upon its turnover in a time interval of ~ 1.5 s. Comparisons between the bacterial Complex I R/A transition and the active/deactive transition of mitochondrial Complex I are discussed.
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33
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Hirst J, Roessler MM. Energy conversion, redox catalysis and generation of reactive oxygen species by respiratory complex I. Biochim Biophys Acta 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] [What about the content of this article? (0)] [Affiliation(s)] [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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34
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Friedrich T, Dekovic DK, Burschel S. Assembly of the Escherichia coli NADH:ubiquinone oxidoreductase (respiratory complex I). Biochim Biophys Acta 2015; 1857:214-23. [PMID: 26682761 DOI: 10.1016/j.bbabio.2015.12.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 12/13/2022]
Abstract
Energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, couples the electron transfer from NADH to ubiquinone with the translocation of four protons across the membrane. The Escherichia coli complex I is made up of 13 different subunits encoded by the so-called nuo-genes. The electron transfer is catalyzed by nine cofactors, a flavin mononucleotide and eight iron-sulfur (Fe/S)-clusters. The individual subunits and the cofactors have to be assembled together in a coordinated way to guarantee the biogenesis of the active holoenzyme. Only little is known about the assembly of the bacterial complex compared to the mitochondrial one. Due to the presence of so many Fe/S-clusters the assembly of complex I is intimately connected with the systems responsible for the biogenesis of these clusters. In addition, a few other proteins have been reported to be required for an effective assembly of the complex in other bacteria. The proposed role of known bacterial assembly factors is discussed and the information from other bacterial species is used in this review to draw an as complete as possible model of bacterial complex I assembly. In addition, the supramolecular organization of the complex in E. coli is briefly described. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof. Conrad Mullineaux.
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Affiliation(s)
- Thorsten Friedrich
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, 79104 Freiburg i. Br., Germany; Spemann Graduate School of Biology and Medicine, Albertstr. 19A, 79104 Freiburg i. Br., Germany.
| | - Doris Kreuzer Dekovic
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, 79104 Freiburg i. Br., Germany; Spemann Graduate School of Biology and Medicine, Albertstr. 19A, 79104 Freiburg i. Br., Germany
| | - Sabrina Burschel
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, 79104 Freiburg i. Br., Germany
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35
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Zhu J, King MS, Yu M, Klipcan L, Leslie AG, Hirst J. Structure of subcomplex Iβ of mammalian respiratory complex I leads to new supernumerary subunit assignments. Proc Natl Acad Sci U S A 2015; 112:12087-92. [PMID: 26371297 DOI: 10.1073/pnas.1510577112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial complex I (proton-pumping NADH:ubiquinone oxidoreductase) is an essential respiratory enzyme. Mammalian complex I contains 45 subunits: 14 conserved "core" subunits and 31 "supernumerary" subunits. The structure of Bos taurus complex I, determined to 5-Å resolution by electron cryomicroscopy, described the structure of the mammalian core enzyme and allowed the assignment of 14 supernumerary subunits. Here, we describe the 6.8-Å resolution X-ray crystallography structure of subcomplex Iβ, a large portion of the membrane domain of B. taurus complex I that contains two core subunits and a cohort of supernumerary subunits. By comparing the structures and composition of subcomplex Iβ and complex I, supported by comparisons with Yarrowia lipolytica complex I, we propose assignments for eight further supernumerary subunits in the structure. Our new assignments include two CHCH-domain containing subunits that contain disulfide bridges between CX9C motifs; they are processed by the Mia40 oxidative-folding pathway in the intermembrane space and probably stabilize the membrane domain. We also assign subunit B22, an LYR protein, to the matrix face of the membrane domain. We reveal that subunit B22 anchors an acyl carrier protein (ACP) to the complex, replicating the LYR protein-ACP structural module that was identified previously in the hydrophilic domain. Thus, we significantly extend knowledge of how the mammalian supernumerary subunits are arranged around the core enzyme, and provide insights into their roles in biogenesis and regulation.
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36
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Lemire BD. Glutathione metabolism links FOXRED1 to NADH:ubiquinone oxidoreductase (complex I) deficiency: A hypothesis. Mitochondrion 2015; 24:105-12. [PMID: 26235939 DOI: 10.1016/j.mito.2015.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 07/10/2015] [Accepted: 07/29/2015] [Indexed: 01/02/2023]
Abstract
FOXRED1 mutations result in complex I (NADH:ubiquinone oxidoreductase) deficiencies and Leigh syndrome (subacute necrotizing encephalomyelopathy). FOXRED1 is a mitochondrial flavoprotein related to N-methyl amino acid dehydrogenases. How is FOXRED1 required for the biogenesis of complex I? I present a hypothesis that suggests FOXRED1 catalytic activity as a sarcosine oxidase protects the developing fetus from oxidative stress during pregnancy. Loss of FOXRED1, coupled with protein, choline and/or folate-deficient diets results in the depletion of glutathione, the dysregulation of nitric oxide metabolism and the peroxynitrite-mediated inactivation of complex I.
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Affiliation(s)
- Bernard D Lemire
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada.
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37
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Stepanova A, Valls A, Galkin A. Effect of monovalent cations on the kinetics of hypoxic conformational change of mitochondrial complex I. Biochim Biophys Acta 2015; 1847:1085-92. [PMID: 26009015 PMCID: PMC4607728 DOI: 10.1016/j.bbabio.2015.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 12/13/2022]
Abstract
Mitochondrial complex I is a large, membrane-bound enzyme central to energy metabolism, and its dysfunction is implicated in cardiovascular and neurodegenerative diseases. An interesting feature of mammalian complex I is the so-called A/D transition, when the idle enzyme spontaneously converts from the active (A) to the de-active, dormant (D) form. The A/D transition plays an important role in tissue response to ischemia and rate of the conversion can be a crucial factor determining outcome of ischemia/reperfusion. Here, we describe the effects of alkali cations on the rate of the D-to-A transition to define whether A/D conversion may be regulated by sodium. At neutral pH (7–7.5) sodium resulted in a clear increase of rates of activation (D-to-A conversion) while other cations had minor effects. The stimulating effect of sodium in this pH range was not caused by an increase in ionic strength. EIPA, an inhibitor of Na+/H+ antiporters, decreased the rate of D-to-A conversion and sodium partially eliminated this effect of EIPA. At higher pH (> 8.0), acceleration of the D-to-A conversion by sodium was abolished, and all tested cations decreased the rate of activation, probably due to the effect of ionic strength. The implications of this finding for the mechanism of complex I energy transduction and possible physiological importance of sodium stimulation of the D-to-A conversion at pathophysiological conditions in vivo are discussed. The active/dormant (A/D) transition of complex I is affected by monovalent cations. Na+ increases the rate of the D/A conversion at neutral pH. Lithium and caesium decrease D/A transition at all tested pH Matrix ion balance may influence the rate of the activation of the enzyme in situ.
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Affiliation(s)
- Anna Stepanova
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK; N.K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilova Str., Moscow 119334, Russia
| | - Alba Valls
- University of Barcelona, Faculty of Biology, Diagonal, 643, 08028 Barcelona, Spain
| | - Alexander Galkin
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
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Lemire BD. A structural model for FOXRED1, an FAD-dependent oxidoreductase necessary for NADH: Ubiquinone oxidoreductase (complex I) assembly. Mitochondrion 2015; 22:9-16. [PMID: 25765152 DOI: 10.1016/j.mito.2015.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/27/2015] [Accepted: 02/27/2015] [Indexed: 01/06/2023]
Abstract
The biogenesis of mitochondrial respiratory chain components is complex. Mammalian complex I (NADH:ubiquinone oxidoreductase) contains 44 different subunits, an FMN and seven iron-sulfur centers. Its assembly involves at least twelve additional proteins, called assembly factors. One of these is FOXRED1, a 486-amino acid FAD-dependent oxidoreductase. FOXRED1 is a member of the d-amino acid oxidase (DAO) family. A structural model of FOXRED1 reveals a large substrate-binding cavity and a putative oxygen-binding site. These features strongly suggest that FOXRED1 is catalytically active as an oxidoreductase. A metabolic role for FOXRED1 in the biogenesis of complex I should be considered.
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Affiliation(s)
- Bernard D Lemire
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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Pätsi J, Kervinen M, Kytövuori L, Majamaa K, Hassinen IE. Effects of pathogenic mutations in membrane subunits of mitochondrial Complex I on redox activity and proton translocation studied by modeling in Escherichia coli. Mitochondrion 2015; 22:23-30. [PMID: 25747201 DOI: 10.1016/j.mito.2015.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/19/2015] [Accepted: 02/24/2015] [Indexed: 01/12/2023]
Abstract
Effects of Complex I mutations were studied by modeling in NuoH, NuoJ or NuoK subunits of Escherichia coli NDH-1 by simultaneous optical monitoring of deamino-NADH oxidation and proton translocation and fitting to the data a model equation of transmembrane proton transport. A homolog of the ND1-E24 LHON/MELAS mutation caused 95% inhibition of d-NADH oxidation and proton translocation. The NuoJ-Y59F replacement decreased proton translocation. The NuoK-E72Q mutation lowered the enzyme activity, but proton pumping could be rescued by the double mutation NuoK-E72Q/I39D. Moving the NuoK-E72/E36 pair one helix turn towards the periplasm did not affect redox activity but decreased proton pumping.
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Affiliation(s)
- Jukka Pätsi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Marko Kervinen
- Department of Ophthalmology and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Laura Kytövuori
- Department of Neurology and Medical Research Center, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Kari Majamaa
- Department of Neurology and Medical Research Center, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
| | - Ilmo E Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
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Gong G, Um Y, Park TH, Woo HM. Complete genome sequence of Enterobacter cloacae GGT036: a furfural tolerant soil bacterium. J Biotechnol 2015; 193:43-4. [PMID: 25444880 DOI: 10.1016/j.jbiotec.2014.11.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
Abstract
Enterobacter cloacae is a facultative anaerobic bacterium to be an important cause of nosocomial infection. However, the isolated E. cloacae GGT036 showed higher furfural-tolerant cellular growth, compared to industrial relevant strains such as Escherichia coli and Corynebacterium glutamicum. Here, we report the complete genome sequence of E. cloacae GGT036 isolated from Mt. Gwanak, Seoul, Republic of Korea. The genomic DNA sequence of E. cloacae GGT036 will provide valuable genetic resources for engineering of industrially relevant strains being tolerant to cellular inhibitors present in lignocellulosic hydrolysates.
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Bazil JN, Pannala VR, Dash RK, Beard DA. Determining the origins of superoxide and hydrogen peroxide in the mammalian NADH:ubiquinone oxidoreductase. Free Radic Biol Med 2014; 77:121-9. [PMID: 25236739 PMCID: PMC4258523 DOI: 10.1016/j.freeradbiomed.2014.08.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 11/26/2022]
Abstract
NADH:ubiquinone oxidoreductase (complex I) is a proton pump in the electron transport chain that can produce a significant amounts of superoxide and hydrogen peroxide. While the flavin mononucleotide (FMN) is the putative site for hydrogen peroxide generation, sites responsible for superoxide are less certain. Here, data on complex I kinetics and ROS generation are analyzed using a computational model to determine the sites responsible for superoxide. The analysis includes all the major redox centers: the FMN, iron-sulfur cluster N2, and semiquinone. Analysis reveals that the fully reduced FMN and semiquinone are the primary sources of superoxide, and the iron-sulfur cluster N2 produces none. The FMN radical only produces ROS when the quinone reductase site is blocked. Model simulations reveal that ROS generation is maximized during reverse electron transport with both the FMN and the semiquinone producing similar amounts of superoxide. In addition, the model successfully predicts the increase in ROS generation when the membrane potential is high and matrix pH is alkaline. Of the total ROS produced by complex I, the majority originates from the FMN.
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Affiliation(s)
- Jason N Bazil
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Venkat R Pannala
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ranjan K Dash
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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Zhang J, Jiang P, Jin X, Liu X, Zhang M, Xie S, Gao M, Zhang S, Sun YH, Zhu J, Ji Y, Wei QP, Tong Y, Guan MX. Leber's hereditary optic neuropathy caused by the homoplasmic ND1 m.3635G>A mutation in nine Han Chinese families. Mitochondrion 2014; 18:18-26. [PMID: 25194554 DOI: 10.1016/j.mito.2014.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 11/18/2022]
Abstract
In this report, we investigated the molecular mechanism underlying Leber's hereditary optic neuropathy (LHON)-associated mitochondrial m.3635G>A (p.S110N, ND1) mutation. A mutational screening of ND1 gene in a cohort of 1070 Han Chinese subjects LHON identified the m.3635G>A mutation in nine Chinese families with suggestively maternally transmitted LHON. Thirty-eight (22 males/16 females) of 162 matrilineal relatives in these families exhibited the variable severity and age-at-onset of optic neuropathy. Molecular analysis of their mitochondrial genomes identified the homoplasmic m.3635G>A mutation and distinct sets of polymorphisms belonging to the Asian haplogroups G2a1, R11a, D4, R11a, M7b2, G1a, F1a1, B4, and N9a3, respectively. Using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from one Chinese family into mtDNA-less (ρ(0)) cells, we showed ~27% decrease in the activity of NADH:ubiquinone oxidoreductase (complex I) in mutant cybrids carrying the m.3635G>A mutation, compared with control cybrids. The respiratory deficiency caused by the m.3635G>A mutation results in decreased efficiency of mitochondrial ATP synthesis. These mitochondrial dysfunctions caused an increase in the production of reactive oxygen species in the mutant cybrids. The data provide the direct evidence for the m.3635G>A mutation leading to LHON. Our findings may provide new insights into the understanding of pathophysiology of LHON.
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Affiliation(s)
- Juanjuan Zhang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China; School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Pingping Jiang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaofen Jin
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Shipeng Xie
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei, China
| | - Min Gao
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Sai Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yan-Hong Sun
- Department of Ophthalmology, Beijing University of Chinese Medicine and Pharmacology, Beijing, China
| | - Jinping Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yanchun Ji
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qi-Ping Wei
- Department of Ophthalmology, Beijing University of Chinese Medicine and Pharmacology, Beijing, China
| | - Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China; Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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43
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Babot M, Labarbuta P, Birch A, Kee S, Fuszard M, Botting CH, Wittig I, Heide H, Galkin A. ND3, ND1 and 39kDa subunits are more exposed in the de-active form of bovine mitochondrial complex I. Biochim Biophys Acta 2014; 1837:929-39. [PMID: 24560811 PMCID: PMC4331043 DOI: 10.1016/j.bbabio.2014.02.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/20/2014] [Accepted: 02/12/2014] [Indexed: 12/12/2022]
Abstract
An intriguing feature of mitochondrial complex I from several species is the so-called A/D transition, whereby the idle enzyme spontaneously converts from the active (A) form to the de-active (D) form. The A/D transition plays an important role in tissue response to the lack of oxygen and hypoxic deactivation of the enzyme is one of the key regulatory events that occur in mitochondria during ischaemia. We demonstrate for the first time that the A/D conformational change of complex I does not affect the macromolecular organisation of supercomplexes in vitro as revealed by two types of native electrophoresis. Cysteine 39 of the mitochondrially-encoded ND3 subunit is known to become exposed upon de-activation. Here we show that even if complex I is a constituent of the I + III2 + IV (S1) supercomplex, cysteine 39 is accessible for chemical modification in only the D-form. Using lysine-specific fluorescent labelling and a DIGE-like approach we further identified two new subunits involved in structural rearrangements during the A/D transition: ND1 (MT-ND1) and 39 kDa (NDUFA9). These results clearly show that structural rearrangements during de-activation of complex I include several subunits located at the junction between hydrophilic and hydrophobic domains, in the region of the quinone binding site. De-activation of mitochondrial complex I results in concerted structural rearrangement of membrane subunits which leads to the disruption of the sealed quinone chamber required for catalytic turnover. Supercomplex composition is not affected by mitochondrial complex I conformation. The D-form of complex I is selectively inhibited by tyrosine-reactive reagents. ND3, ND1 & 39 kDa subunits become exposed upon deactivation of complex I.
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Affiliation(s)
- Marion Babot
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Paola Labarbuta
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Amanda Birch
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Sara Kee
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Matthew Fuszard
- School of Chemistry, Biomedical Sciences Research Complex, BMS Annexe, University of St. Andrews, KY16 9ST, UK
| | - Catherine H Botting
- School of Chemistry, Biomedical Sciences Research Complex, BMS Annexe, University of St. Andrews, KY16 9ST, UK
| | - Ilka Wittig
- Functional Proteomics, SFB Core Unit, Faculty of Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Heinrich Heide
- Functional Proteomics, SFB Core Unit, Faculty of Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Alexander Galkin
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
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Abstract
Mitochondrial respiratory complex I is a product of both the nuclear and mitochondrial genomes. The integration of seven subunits encoded in mitochondrial DNA into the inner membrane, their association with 14 nuclear-encoded membrane subunits, the construction of the extrinsic arm from 23 additional nuclear-encoded proteins, iron-sulfur clusters, and flavin mononucleotide cofactor require the participation of assembly factors. Some are intrinsic to the complex, whereas others participate transiently. The suppression of the expression of the NDUFA11 subunit of complex I disrupted the assembly of the complex, and subcomplexes with masses of 550 and 815 kDa accumulated. Eight of the known extrinsic assembly factors plus a hydrophobic protein, C3orf1, were associated with the subcomplexes. The characteristics of C3orf1, of another assembly factor, TMEM126B, and of NDUFA11 suggest that they all participate in constructing the membrane arm of complex I.
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