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Yin Z, Agip ANA, Bridges HR, Hirst J. Structural insights into respiratory complex I deficiency and assembly from the mitochondrial disease-related ndufs4 -/- mouse. EMBO J 2024; 43:225-249. [PMID: 38177503 PMCID: PMC10897435 DOI: 10.1038/s44318-023-00001-4] [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: 07/15/2023] [Revised: 10/30/2023] [Accepted: 11/07/2023] [Indexed: 01/06/2024] Open
Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase) is essential for cellular energy production and NAD+ homeostasis. Complex I mutations cause neuromuscular, mitochondrial diseases, such as Leigh Syndrome, but their molecular-level consequences remain poorly understood. Here, we use a popular complex I-linked mitochondrial disease model, the ndufs4-/- mouse, to define the structural, biochemical, and functional consequences of the absence of subunit NDUFS4. Cryo-EM analyses of the complex I from ndufs4-/- mouse hearts revealed a loose association of the NADH-dehydrogenase module, and discrete classes containing either assembly factor NDUFAF2 or subunit NDUFS6. Subunit NDUFA12, which replaces its paralogue NDUFAF2 in mature complex I, is absent from all classes, compounding the deletion of NDUFS4 and preventing maturation of an NDUFS4-free enzyme. We propose that NDUFAF2 recruits the NADH-dehydrogenase module during assembly of the complex. Taken together, the findings provide new molecular-level understanding of the ndufs4-/- mouse model and complex I-linked mitochondrial disease.
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Affiliation(s)
- Zhan Yin
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Ahmed-Noor A Agip
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
- Max-Planck-Institute of Biophysics, Frankfurt, 60438, Germany
| | - Hannah R Bridges
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK.
- Structura Biotechnology Inc., Toronto, Canada.
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK.
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2
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Fang Z, Corbizi Fattori G, McKerrell T, Boucher RH, Jackson A, Fletcher RS, Forte D, Martin JE, Fox S, Roberts J, Glover R, Harris E, Bridges HR, Grassi L, Rodriguez-Meira A, Mead AJ, Knapper S, Ewing J, Butt NM, Jain M, Francis S, Clark FJ, Coppell J, McMullin MF, Wadelin F, Narayanan S, Milojkovic D, Drummond MW, Sekhar M, ElDaly H, Hirst J, Paramor M, Baxter EJ, Godfrey AL, Harrison CN, Méndez-Ferrer S. Tamoxifen for the treatment of myeloproliferative neoplasms: A Phase II clinical trial and exploratory analysis. Nat Commun 2023; 14:7725. [PMID: 38001082 PMCID: PMC10673935 DOI: 10.1038/s41467-023-43175-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Current therapies for myeloproliferative neoplasms (MPNs) improve symptoms but have limited effect on tumor size. In preclinical studies, tamoxifen restored normal apoptosis in mutated hematopoietic stem/progenitor cells (HSPCs). TAMARIN Phase-II, multicenter, single-arm clinical trial assessed tamoxifen's safety and activity in patients with stable MPNs, no prior thrombotic events and mutated JAK2V617F, CALRins5 or CALRdel52 peripheral blood allele burden ≥20% (EudraCT 2015-005497-38). 38 patients were recruited over 112w and 32 completed 24w-treatment. The study's A'herns success criteria were met as the primary outcome ( ≥ 50% reduction in mutant allele burden at 24w) was observed in 3/38 patients. Secondary outcomes included ≥25% reduction at 24w (5/38), ≥50% reduction at 12w (0/38), thrombotic events (2/38), toxicities, hematological response, proportion of patients in each IWG-MRT response category and ELN response criteria. As exploratory outcomes, baseline analysis of HSPC transcriptome segregates responders and non-responders, suggesting a predictive signature. In responder HSPCs, longitudinal analysis shows high baseline expression of JAK-STAT signaling and oxidative phosphorylation genes, which are downregulated by tamoxifen. We further demonstrate in preclinical studies that in JAK2V617F+ cells, 4-hydroxytamoxifen inhibits mitochondrial complex-I, activates integrated stress response and decreases pathogenic JAK2-signaling. These results warrant further investigation of tamoxifen in MPN, with careful consideration of thrombotic risk.
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Affiliation(s)
- Zijian Fang
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- NHS Blood and Transplant, Cambridge, UK
| | - Giuditta Corbizi Fattori
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- NHS Blood and Transplant, Cambridge, UK
| | - Thomas McKerrell
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK
- NHS Blood and Transplant, Cambridge, UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Rebecca H Boucher
- Cancer Research UK Clinical Trials Unit, University of Birmingham, Birmingham, UK
| | - Aimee Jackson
- Cancer Research UK Clinical Trials Unit, University of Birmingham, Birmingham, UK
| | - Rachel S Fletcher
- Cancer Research UK Clinical Trials Unit, University of Birmingham, Birmingham, UK
| | - Dorian Forte
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- NHS Blood and Transplant, Cambridge, UK
| | - Jose-Ezequiel Martin
- Cancer Molecular Diagnostic Laboratory, Department of Oncology, University of Cambridge, Cambridge, UK
| | - Sonia Fox
- Cancer Research UK Clinical Trials Unit, University of Birmingham, Birmingham, UK
| | - James Roberts
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Rachel Glover
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Erica Harris
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Hannah R Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Luigi Grassi
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Alba Rodriguez-Meira
- NIHR Biomedical Research Centre and MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Adam J Mead
- NIHR Biomedical Research Centre and MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | | | - Joanne Ewing
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Nauman M Butt
- The Clatterbridge Cancer Centre NHS Foundation Trust, Liverpool, UK
| | | | | | - Fiona J Clark
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | | | | | | | | | | | | | - Hesham ElDaly
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Maike Paramor
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK
| | - E Joanna Baxter
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Anna L Godfrey
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | | | - Simón Méndez-Ferrer
- Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK.
- Department of Haematology, University of Cambridge, Cambridge, UK.
- NHS Blood and Transplant, Cambridge, UK.
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3
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Milenkovic D, Misic J, Hevler JF, Molinié T, Chung I, Atanassov I, Li X, Filograna R, Mesaros A, Mourier A, Heck AJR, Hirst J, Larsson NG. Preserved respiratory chain capacity and physiology in mice with profoundly reduced levels of mitochondrial respirasomes. Cell Metab 2023; 35:1799-1813.e7. [PMID: 37633273 DOI: 10.1016/j.cmet.2023.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/23/2023] [Accepted: 07/29/2023] [Indexed: 08/28/2023]
Abstract
The mammalian respiratory chain complexes I, III2, and IV (CI, CIII2, and CIV) are critical for cellular bioenergetics and form a stable assembly, the respirasome (CI-CIII2-CIV), that is biochemically and structurally well documented. The role of the respirasome in bioenergetics and the regulation of metabolism is subject to intense debate and is difficult to study because the individual respiratory chain complexes coexist together with high levels of respirasomes. To critically investigate the in vivo role of the respirasome, we generated homozygous knockin mice that have normal levels of respiratory chain complexes but profoundly decreased levels of respirasomes. Surprisingly, the mutant mice are healthy, with preserved respiratory chain capacity and normal exercise performance. Our findings show that high levels of respirasomes are dispensable for maintaining bioenergetics and physiology in mice but raise questions about their alternate functions, such as those relating to the regulation of protein stability and prevention of age-associated protein aggregation.
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Affiliation(s)
- Dusanka Milenkovic
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - Jelena Misic
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Johannes F Hevler
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Thibaut Molinié
- University of Bordeaux, CNRS, IBGC, UMR 5095, 33000 Bordeaux, France
| | - Injae Chung
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Ilian Atanassov
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Xinping Li
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Roberta Filograna
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Andrea Mesaros
- Phenotyping Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Arnaud Mourier
- University of Bordeaux, CNRS, IBGC, UMR 5095, 33000 Bordeaux, France
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
| | - Nils-Göran Larsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden.
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4
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Grba DN, Chung I, Bridges HR, Agip ANA, Hirst J. Investigation of hydrated channels and proton pathways in a high-resolution cryo-EM structure of mammalian complex I. Sci Adv 2023; 9:eadi1359. [PMID: 37531432 PMCID: PMC10396290 DOI: 10.1126/sciadv.adi1359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/03/2023] [Indexed: 08/04/2023]
Abstract
Respiratory complex I, a key enzyme in mammalian metabolism, captures the energy released by reduction of ubiquinone by NADH to drive protons across the inner mitochondrial membrane, generating the proton-motive force for ATP synthesis. Despite remarkable advances in structural knowledge of this complicated membrane-bound enzyme, its mechanism of catalysis remains controversial. In particular, how ubiquinone reduction is coupled to proton pumping and the pathways and mechanisms of proton translocation are contested. We present a 2.4-Å resolution cryo-EM structure of complex I from mouse heart mitochondria in the closed, active (ready-to-go) resting state, with 2945 water molecules modeled. By analyzing the networks of charged and polar residues and water molecules present, we evaluate candidate pathways for proton transfer through the enzyme, for the chemical protons for ubiquinone reduction, and for the protons transported across the membrane. Last, we compare our data to the predictions of extant mechanistic models, and identify key questions to answer in future work to test them.
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5
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Hardy RE, Chung I, Yu Y, Loh SHY, Morone N, Soleilhavoup C, Travaglio M, Serreli R, Panman L, Cain K, Hirst J, Martins LM, MacFarlane M, Pryde KR. The antipsychotic medications aripiprazole, brexpiprazole and cariprazine are off-target respiratory chain complex I inhibitors. Biol Direct 2023; 18:43. [PMID: 37528429 PMCID: PMC10391878 DOI: 10.1186/s13062-023-00375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 08/03/2023] Open
Abstract
Antipsychotic drugs are the mainstay of treatment for schizophrenia and provide adjunct therapies for other prevalent psychiatric conditions, including bipolar disorder and major depressive disorder. However, they also induce debilitating extrapyramidal syndromes (EPS), such as Parkinsonism, in a significant minority of patients. The majority of antipsychotic drugs function as dopamine receptor antagonists in the brain while the most recent 'third'-generation, such as aripiprazole, act as partial agonists. Despite showing good clinical efficacy, these newer agents are still associated with EPS in ~ 5 to 15% of patients. However, it is not fully understood how these movement disorders develop. Here, we combine clinically-relevant drug concentrations with mutliscale model systems to show that aripiprazole and its primary active metabolite induce mitochondrial toxicity inducing robust declines in cellular ATP and viability. Aripiprazole, brexpiprazole and cariprazine were shown to directly inhibit respiratory complex I through its ubiquinone-binding channel. Importantly, all three drugs induced mitochondrial toxicity in primary embryonic mouse neurons, with greater bioenergetic inhibition in ventral midbrain neurons than forebrain neurons. Finally, chronic feeding with aripiprazole resulted in structural damage to mitochondria in the brain and thoracic muscle of adult Drosophila melanogaster consistent with locomotor dysfunction. Taken together, we show that antipsychotic drugs acting as partial dopamine receptor agonists exhibit off-target mitochondrial liabilities targeting complex I.
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Affiliation(s)
- Rachel E Hardy
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Yizhou Yu
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Samantha H Y Loh
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Nobuhiro Morone
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Clement Soleilhavoup
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Marco Travaglio
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Riccardo Serreli
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Lia Panman
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Kelvin Cain
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Luis M Martins
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK.
| | - Marion MacFarlane
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK.
| | - Kenneth R Pryde
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge, CB2 1QR, UK.
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6
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Pereira CS, Teixeira MH, Russell DA, Hirst J, Arantes GM. Mechanism of rotenone binding to respiratory complex I depends on ligand flexibility. Sci Rep 2023; 13:6738. [PMID: 37185607 PMCID: PMC10130173 DOI: 10.1038/s41598-023-33333-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/11/2023] [Indexed: 05/17/2023] Open
Abstract
Respiratory complex I is a major cellular energy transducer located in the inner mitochondrial membrane. Its inhibition by rotenone, a natural isoflavonoid, has been used for centuries by indigenous peoples to aid in fishing and, more recently, as a broad-spectrum pesticide or even a possible anticancer therapeutic. Unraveling the molecular mechanism of rotenone action will help to design tuned derivatives and to understand the still mysterious catalytic mechanism of complex I. Although composed of five fused rings, rotenone is a flexible molecule and populates two conformers, bent and straight. Here, a rotenone derivative locked in the straight form was synthesized and found to inhibit complex I with 600-fold less potency than natural rotenone. Large-scale molecular dynamics and free energy simulations of the pathway for ligand binding to complex I show that rotenone is more stable in the bent conformer, either free in the membrane or bound to the redox active site in the substrate-binding Q-channel. However, the straight conformer is necessary for passage from the membrane through the narrow entrance of the channel. The less potent inhibition of the synthesized derivative is therefore due to its lack of internal flexibility, and interconversion between bent and straight forms is required to enable efficient kinetics and high stability for rotenone binding. The ligand also induces reconfiguration of protein loops and side-chains inside the Q-channel similar to structural changes that occur in the open to closed conformational transition of complex I. Detailed understanding of ligand flexibility and interactions that determine rotenone binding may now be exploited to tune the properties of synthetic derivatives for specific applications.
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Affiliation(s)
- Caroline S Pereira
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-900, Brazil
| | - Murilo H Teixeira
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-900, Brazil
| | - David A Russell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
| | - Guilherme M Arantes
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-900, Brazil.
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7
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Abstract
The molecular mode of action of biguanides, including the drug metformin, which is widely used in the treatment of diabetes, is incompletely characterized. Here, we define the inhibitory drug-target interaction(s) of a model biguanide with mammalian respiratory complex I by combining cryo-electron microscopy and enzyme kinetics. We interpret these data to explain the selectivity of biguanide binding to different enzyme states. The primary inhibitory site is in an amphipathic region of the quinone-binding channel, and an additional binding site is in a pocket on the intermembrane-space side of the enzyme. An independent local chaotropic interaction, not previously described for any drug, displaces a portion of a key helix in the membrane domain. Our data provide a structural basis for biguanide action and enable the rational design of medicinal biguanides.
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Affiliation(s)
- Hannah R. Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Authors for correspondence: and
| | - James N. Blaza
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Structural Biology Laboratory and York Biomedical Research Institute, Department of Chemistry, The University of York, YO10 5DD, UK
| | - Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Michael N. Pollak
- Lady Davis Institute of the Jewish General Hospital and Department of Oncology, McGill University, Montreal, QC H3T 1E2, Canada
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK,Authors for correspondence: and
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8
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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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9
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Eisermann J, Wright JJ, Wilton-Ely J, Hirst J, Roessler M. Using light scattering to assess how phospholipid-protein interactions affect complex I functionality in liposomes. RSC Chem Biol 2023. [DOI: 10.1039/d2cb00158f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023] Open
Abstract
Complex I is an essential membrane protein in respiration, oxidising NADH and reducing ubiquinone to contribute to the proton-motive force that powers ATP synthesis. Liposomes provide an attractive platform to...
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10
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Chung I, Grba DN, Wright JJ, Hirst J. Making the leap from structure to mechanism: are the open states of mammalian complex I identified by cryoEM resting states or catalytic intermediates? Curr Opin Struct Biol 2022; 77:102447. [PMID: 36087446 PMCID: PMC7614202 DOI: 10.1016/j.sbi.2022.102447] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/07/2022] [Accepted: 07/26/2022] [Indexed: 12/14/2022]
Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase) is a multi-subunit, energy-transducing mitochondrial enzyme that is essential for oxidative phosphorylation and regulating NAD+/NADH pools. Despite recent advances in structural knowledge and a long history of biochemical analyses, the mechanism of redox-coupled proton translocation by complex I remains unknown. Due to its ability to separate molecules in a mixed population into distinct classes, single-particle electron cryomicroscopy has enabled identification and characterisation of different complex I conformations. However, deciding on their catalytic and/or regulatory properties to underpin mechanistic hypotheses, especially without detailed biochemical characterisation of the structural samples, has proven challenging. In this review we explore different mechanistic interpretations of the closed and open states identified in cryoEM analyses of mammalian complex I.
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Affiliation(s)
- Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Daniel N Grba
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - John J Wright
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
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11
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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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12
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Wright JJ, Biner O, Chung I, Burger N, Bridges HR, Hirst J. Reverse Electron Transfer by Respiratory Complex I Catalyzed in a Modular Proteoliposome System. J Am Chem Soc 2022; 144:6791-6801. [PMID: 35380814 PMCID: PMC9026280 DOI: 10.1021/jacs.2c00274] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Indexed: 02/02/2023]
Abstract
Respiratory complex I is an essential metabolic enzyme that uses the energy from NADH oxidation and ubiquinone reduction to translocate protons across an energy transducing membrane and generate the proton motive force for ATP synthesis. Under specific conditions, complex I can also catalyze the reverse reaction, Δp-linked oxidation of ubiquinol to reduce NAD+ (or O2), known as reverse electron transfer (RET). Oxidative damage by reactive oxygen species generated during RET underpins ischemia reperfusion injury, but as RET relies on several converging metabolic pathways, little is known about its mechanism or regulation. Here, we demonstrate Δp-linked RET through complex I in a synthetic proteoliposome system for the first time, enabling complete kinetic characterization of RET catalysis. We further establish the capability of our system by showing how RET in the mammalian enzyme is regulated by the active-deactive transition and by evaluating RET by complex I from several species in which direct assessment has not been otherwise possible. We thus provide new insights into the reversibility of complex I catalysis, an important but little understood mechanistic and physiological feature.
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Affiliation(s)
- John J. Wright
- Medical Research Council
Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, U.K.
| | | | - Injae Chung
- Medical Research Council
Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, U.K.
| | | | - Hannah R. Bridges
- Medical Research Council
Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, U.K.
| | - Judy Hirst
- Medical Research Council
Mitochondrial Biology Unit, University of
Cambridge, Cambridge CB2 0XY, U.K.
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13
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Grba DN, Blaza JN, Bridges HR, Agip ANA, Yin Z, Murai M, Miyoshi H, Hirst J. Cryo-electron microscopy reveals how acetogenins inhibit mitochondrial respiratory complex I. J Biol Chem 2022; 298:101602. [PMID: 35063503 PMCID: PMC8861642 DOI: 10.1016/j.jbc.2022.101602] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [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: 10/22/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial complex I (NADH:ubiquinone oxidoreductase), a crucial enzyme in energy metabolism, captures the redox potential energy from NADH oxidation/ubiquinone reduction to create the proton motive force used to drive ATP synthesis in oxidative phosphorylation. High-resolution single-particle electron cryo-EM analyses have provided detailed structural knowledge of the catalytic machinery of complex I, but not of the molecular principles of its energy transduction mechanism. Although ubiquinone is considered to bind in a long channel at the interface of the membrane-embedded and hydrophilic domains, with channel residues likely involved in coupling substrate reduction to proton translocation, no structures with the channel fully occupied have yet been described. Here, we report the structure (determined by cryo-EM) of mouse complex I with a tight-binding natural product acetogenin inhibitor, which resembles the native substrate, bound along the full length of the expected ubiquinone-binding channel. Our structure reveals the mode of acetogenin binding and the molecular basis for structure-activity relationships within the acetogenin family. It also shows that acetogenins are such potent inhibitors because they are highly hydrophobic molecules that contain two specific hydrophilic moieties spaced to lock into two hydrophilic regions of the otherwise hydrophobic channel. The central hydrophilic section of the channel does not favor binding of the isoprenoid chain when the native substrate is fully bound but stabilizes the ubiquinone/ubiquinol headgroup as it transits to/from the active site. Therefore, the amphipathic nature of the channel supports both tight binding of the amphipathic inhibitor and rapid exchange of the ubiquinone/ubiquinol substrate and product.
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Affiliation(s)
- Daniel N Grba
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - James N Blaza
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Hannah R Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Ahmed-Noor A Agip
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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14
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Jarman OD, Biner O, Wright JJ, Hirst J. Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I. Sci Rep 2021; 11:10143. [PMID: 33980947 PMCID: PMC8115037 DOI: 10.1038/s41598-021-89575-9] [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: 03/30/2021] [Accepted: 04/27/2021] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.
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Affiliation(s)
- Owen D. Jarman
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Olivier Biner
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - John J. Wright
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Judy Hirst
- grid.5335.00000000121885934The 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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15
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Chung I, Serreli R, Cross JB, Di Francesco ME, Marszalek JR, Hirst J. Cork-in-bottle mechanism of inhibitor binding to mammalian complex I. Sci Adv 2021; 7:7/20/eabg4000. [PMID: 33990335 PMCID: PMC8121435 DOI: 10.1126/sciadv.abg4000] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/26/2021] [Indexed: 05/08/2023]
Abstract
Mitochondrial complex I (NADH:ubiquinone oxidoreductase), a major contributor of free energy for oxidative phosphorylation, is increasingly recognized as a promising drug target for ischemia-reperfusion injury, metabolic disorders, and various cancers. Several pharmacologically relevant but structurally unrelated small molecules have been identified as specific complex I inhibitors, but their modes of action remain unclear. Here, we present a 3.0-Å resolution cryo-electron microscopy structure of mammalian complex I inhibited by a derivative of IACS-010759, which is currently in clinical development against cancers reliant on oxidative phosphorylation, revealing its unique cork-in-bottle mechanism of inhibition. We combine structural and kinetic analyses to deconvolute cross-species differences in inhibition and identify the structural motif of a "chain" of aromatic rings as a characteristic that promotes inhibition. Our findings provide insights into the importance of π-stacking residues for inhibitor binding in the long substrate-binding channel in complex I and a guide for future biorational drug design.
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Affiliation(s)
- Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Riccardo Serreli
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Jason B Cross
- Institute for Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - M Emilia Di Francesco
- Institute for Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Joseph R Marszalek
- TRACTION-Translational Research to AdvanCe Therapeutics and Innovation in ONcology, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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16
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Maclean AE, Bridges HR, Silva MF, Ding S, Ovciarikova J, Hirst J, Sheiner L. Complexome profile of Toxoplasma gondii mitochondria identifies divergent subunits of respiratory chain complexes including new subunits of cytochrome bc1 complex. PLoS Pathog 2021; 17:e1009301. [PMID: 33651838 PMCID: PMC7987180 DOI: 10.1371/journal.ppat.1009301] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/23/2021] [Accepted: 01/11/2021] [Indexed: 12/30/2022] Open
Abstract
The mitochondrial electron transport chain (mETC) and F1Fo-ATP synthase are of central importance for energy and metabolism in eukaryotic cells. The Apicomplexa, important pathogens of humans causing diseases such as toxoplasmosis and malaria, depend on their mETC in every known stage of their complicated life cycles. Here, using a complexome profiling proteomic approach, we have characterised the Toxoplasma mETC complexes and F1Fo-ATP synthase. We identified and assigned 60 proteins to complexes II, IV and F1Fo-ATP synthase of Toxoplasma, of which 16 have not been identified previously. Notably, our complexome profile elucidates the composition of the Toxoplasma complex III, the target of clinically used drugs such as atovaquone. We identified two new homologous subunits and two new parasite-specific subunits, one of which is broadly conserved in myzozoans. We demonstrate all four proteins are essential for complex III stability and parasite growth, and show their depletion leads to decreased mitochondrial potential, supporting their assignment as complex III subunits. Our study highlights the divergent subunit composition of the apicomplexan mETC and F1Fo-ATP synthase complexes and sets the stage for future structural and drug discovery studies.
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Affiliation(s)
- Andrew E. Maclean
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Hannah R. Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Mariana F. Silva
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Shujing Ding
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Jana Ovciarikova
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Lilach Sheiner
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
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17
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Yin Z, Burger N, Kula-Alwar D, Aksentijević D, Bridges HR, Prag HA, Grba DN, Viscomi C, James AM, Mottahedin A, Krieg T, Murphy MP, Hirst J. Structural basis for a complex I mutation that blocks pathological ROS production. Nat Commun 2021; 12:707. [PMID: 33514727 PMCID: PMC7846746 DOI: 10.1038/s41467-021-20942-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [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: 09/22/2020] [Accepted: 12/23/2020] [Indexed: 02/02/2023] Open
Abstract
Mitochondrial complex I is central to the pathological reactive oxygen species (ROS) production that underlies cardiac ischemia-reperfusion (IR) injury. ND6-P25L mice are homoplasmic for a disease-causing mtDNA point mutation encoding the P25L substitution in the ND6 subunit of complex I. The cryo-EM structure of ND6-P25L complex I revealed subtle structural changes that facilitate rapid conversion to the "deactive" state, usually formed only after prolonged inactivity. Despite its tendency to adopt the "deactive" state, the mutant complex is fully active for NADH oxidation, but cannot generate ROS by reverse electron transfer (RET). ND6-P25L mitochondria function normally, except for their lack of RET ROS production, and ND6-P25L mice are protected against cardiac IR injury in vivo. Thus, this single point mutation in complex I, which does not affect oxidative phosphorylation but renders the complex unable to catalyse RET, demonstrates the pathological role of ROS production by RET during IR injury.
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Affiliation(s)
- Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Nils Burger
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Dunja Aksentijević
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, London, UK
| | - Hannah R Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Hiran A Prag
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Daniel N Grba
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Carlo Viscomi
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Department of Biomedical Sciences, University of Padova via Ugo Bassi 58/B, Padova, 35131, Italy
| | - Andrew M James
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Amin Mottahedin
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Thomas Krieg
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
- Department of Medicine, University of Cambridge, Cambridge, UK.
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
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18
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Jarman OD, Biner O, Hirst J. Regulation of ATP hydrolysis by the ε subunit, ζ subunit and Mg-ADP in the ATP synthase of Paracoccus denitrificans. Biochim Biophys Acta Bioenerg 2020; 1862:148355. [PMID: 33321110 PMCID: PMC8039183 DOI: 10.1016/j.bbabio.2020.148355] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/27/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022]
Abstract
F1FO-ATP synthase is a crucial metabolic enzyme that uses the proton motive force from respiration to regenerate ATP. For maximum thermodynamic efficiency ATP synthesis should be fully reversible, but the enzyme from Paracoccus denitrificans catalyzes ATP hydrolysis at far lower rates than it catalyzes ATP synthesis, an effect often attributed to its unique ζ subunit. Recently, we showed that deleting ζ increases hydrolysis only marginally, indicating that other common inhibitory mechanisms such as inhibition by the C-terminal domain of the ε subunit (ε-CTD) or Mg-ADP may be more important. Here, we created mutants lacking the ε-CTD, and double mutants lacking both the ε-CTD and ζ subunit. No substantial activation of ATP hydrolysis was observed in any of these strains. Instead, hydrolysis in even the double mutant strains could only be activated by oxyanions, the detergent lauryldimethylamine oxide, or a proton motive force, which are all considered to release Mg-ADP inhibition. Our results establish that P. denitrificans ATP synthase is regulated by a combination of the ε and ζ subunits and Mg-ADP inhibition.
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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
| | - Olivier Biner
- 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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19
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Grba DN, Hirst J. Mitochondrial complex I structure reveals ordered water molecules for catalysis and proton translocation. Nat Struct Mol Biol 2020; 27:892-900. [PMID: 32747785 PMCID: PMC7612091 DOI: 10.1038/s41594-020-0473-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/26/2020] [Indexed: 01/09/2023]
Abstract
Mitochondrial complex I powers ATP synthesis by oxidative phosphorylation, exploiting the energy from ubiquinone reduction by NADH to drive protons across the energy-transducing inner membrane. Recent cryo-EM analyses of mammalian and yeast complex I have revolutionized structural and mechanistic knowledge and defined structures in different functional states. Here, we describe a 2.7-Å-resolution structure of the 42-subunit complex I from the yeast Yarrowia lipolytica containing 275 structured water molecules. We identify a proton-relay pathway for ubiquinone reduction and water molecules that connect mechanistically crucial elements and constitute proton-translocation pathways through the membrane. By comparison with known structures, we deconvolute structural changes governing the mammalian 'deactive transition' (relevant to ischemia-reperfusion injury) and their effects on the ubiquinone-binding site and a connected cavity in ND1. Our structure thus provides important insights into catalysis by this enigmatic respiratory machine.
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Affiliation(s)
- Daniel N Grba
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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20
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Robinson WE, Bassegoda A, Blaza JN, Reisner E, Hirst J. Understanding How the Rate of C-H Bond Cleavage Affects Formate Oxidation Catalysis by a Mo-Dependent Formate Dehydrogenase. J Am Chem Soc 2020; 142:12226-12236. [PMID: 32551568 PMCID: PMC7366381 DOI: 10.1021/jacs.0c03574] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metal-dependent formate dehydrogenases (FDHs) catalyze the reversible conversion of formate into CO2, a proton, and two electrons. Kinetic studies of FDHs provide key insights into their mechanism of catalysis, relevant as a guide for the development of efficient electrocatalysts for formate oxidation as well as for CO2 capture and utilization. Here, we identify and explain the kinetic isotope effect (KIE) observed for the oxidation of formate and deuterioformate by the Mo-containing FDH from Escherichia coli using three different techniques: steady-state solution kinetic assays, protein film electrochemistry (PFE), and pre-steady-state stopped-flow methods. For each technique, the Mo center of FDH is reoxidized at a different rate following formate oxidation, significantly affecting the observed kinetic behavior and providing three different viewpoints on the KIE. Steady-state turnover in solution, using an artificial electron acceptor, is kinetically limited by diffusional intermolecular electron transfer, masking the KIE. In contrast, interfacial electron transfer in PFE is fast, lifting the electron-transfer rate limitation and manifesting a KIE of 2.44. Pre-steady-state analyses using stopped-flow spectroscopy revealed a KIE of 3 that can be assigned to the C-H bond cleavage step during formate oxidation. We formalize our understanding of FDH catalysis by fitting all the data to a single kinetic model, recreating the condition-dependent shift in rate-limitation of FDH catalysis between active-site chemical catalysis and regenerative electron transfer. Furthermore, our model predicts the steady-state and time-dependent concentrations of catalytic intermediates, providing a valuable framework for the design of future mechanistic experiments.
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Affiliation(s)
- William E Robinson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Arnau Bassegoda
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
| | - James N Blaza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
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21
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Russell DA, Bridges HR, Serreli R, Kidd SL, Mateu N, Osberger TJ, Sore HF, Hirst J, Spring DR. Hydroxylated Rotenoids Selectively Inhibit the Proliferation of Prostate Cancer Cells. J Nat Prod 2020; 83:1829-1845. [PMID: 32459967 PMCID: PMC7611836 DOI: 10.1021/acs.jnatprod.9b01224] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Prostate cancer is one of the leading causes of cancer-related death in men. The identification of new therapeutics to selectively target prostate cancer cells is therefore vital. Recently, the rotenoids rotenone (1) and deguelin (2) were reported to selectively kill prostate cancer cells, and the inhibition of mitochondrial complex I was established as essential to their mechanism of action. However, these hydrophobic rotenoids readily cross the blood-brain barrier and induce symptoms characteristic of Parkinson's disease in animals. Since hydroxylated derivatives of 1 and 2 are more hydrophilic and less likely to readily cross the blood-brain barrier, 29 natural and unnatural hydroxylated derivatives of 1 and 2 were synthesized for evaluation. The inhibitory potency (IC50) of each derivative against complex I was measured, and its hydrophobicity (Slog10P) predicted. Amorphigenin (3), dalpanol (4), dihydroamorphigenin (5), and amorphigenol (6) were selected and evaluated in cell-based assays using C4-2 and C4-2B prostate cancer cells alongside control PNT2 prostate cells. These rotenoids inhibit complex I in cells, decrease oxygen consumption, and selectively inhibit the proliferation of prostate cancer cells, leaving control cells unaffected. The greatest selectivity and antiproliferative effects were observed with 3 and 5. The data highlight these molecules as promising therapeutic candidates for further evaluation in prostate cancer models.
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Affiliation(s)
- David A. Russell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Hannah R. Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Riccardo Serreli
- MRC Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - Sarah L. Kidd
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Natalia Mateu
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Thomas J. Osberger
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Hannah F. Sore
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, U.K
| | - David R. Spring
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
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22
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Abstract
Adenosine triphosphate (ATP), the cellular energy currency, is essential for life. The ability to provide a constant supply of ATP is therefore crucial for the construction of artificial cells in synthetic biology. Here, we describe the bottom-up assembly and characterization of a minimal respiratory system that uses NADH as a fuel to produce ATP from ADP and inorganic phosphate, and is thus capable of sustaining both upstream metabolic processes that rely on NAD+, and downstream energy-demanding processes that are powered by ATP hydrolysis. A detergent-mediated approach was used to co-reconstitute respiratory mitochondrial complex I and an F-type ATP synthase into nanosized liposomes. Addition of the alternative oxidase to the resulting proteoliposomes produced a minimal artificial "organelle" that reproduces the energy-converting catalytic reactions of the mitochondrial respiratory chain: NADH oxidation, ubiquinone cycling, oxygen reduction, proton pumping, and ATP synthesis. As a proof-of-principle, we demonstrate that our nanovesicles are capable of using an NAD+-linked substrate to drive cell-free protein expression. Our nanovesicles are both efficient and durable and may be applied to sustain artificial cells in future work.
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Affiliation(s)
- Olivier Biner
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Justin G Fedor
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
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23
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Stephenson ZA, Harvey RF, Pryde KR, Mistry S, Hardy RE, Serreli R, Chung I, Allen TE, Stoneley M, MacFarlane M, Fischer PM, Hirst J, Kellam B, Willis AE. Identification of a novel toxicophore in anti-cancer chemotherapeutics that targets mitochondrial respiratory complex I. eLife 2020; 9:55845. [PMID: 32432547 PMCID: PMC7316505 DOI: 10.7554/elife.55845] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/20/2020] [Indexed: 12/27/2022] Open
Abstract
Disruption of mitochondrial function selectively targets tumour cells that are dependent on oxidative phosphorylation. However, due to their high energy demands, cardiac cells are disproportionately targeted by mitochondrial toxins resulting in a loss of cardiac function. An analysis of the effects of mubritinib on cardiac cells showed that this drug did not inhibit HER2 as reported, but directly inhibits mitochondrial respiratory complex I, reducing cardiac-cell beat rate, with prolonged exposure resulting in cell death. We used a library of chemical variants of mubritinib and showed that modifying the 1H-1,2,3-triazole altered complex I inhibition, identifying the heterocyclic 1,3-nitrogen motif as the toxicophore. The same toxicophore is present in a second anti-cancer therapeutic carboxyamidotriazole (CAI) and we demonstrate that CAI also functions through complex I inhibition, mediated by the toxicophore. Complex I inhibition is directly linked to anti-cancer cell activity, with toxicophore modification ablating the desired effects of these compounds on cancer cell proliferation and apoptosis. The pharmaceutical industry needs to make safe and effective drugs. At the same time this industry is under pressure to keep the costs of developing these drugs at an acceptable level. Drugs work by interacting with and typically blocking a specific target, such as a protein in a particular type of cell. Sometimes, however, drugs also bind other unexpected targets. These “off-target” effects can be the reason for a drug’s toxicity, and it is important – both for the benefit of patients and the money that can be saved when developing drugs – to identify how drugs cause toxic side effects. The earlier researchers detect off-target effects, the better. Recent data has suggested that an anti-cancer drug called mubritinib has off-target effects on the compartments within cells that provide the cell with most of their energy, the mitochondria. This drug’s intended target is a protein called HER2, which is found in large amounts on the surfaces of some breast cancer cells. Yet if mubritinib has this off-target effect on mitochondria, it may be harmful to other cells including heart cells because the heart is an organ that needs a large amount of energy from its mitochondria. Stephenson et al. have now performed experiments to show that mubritinib does not actually interact with HER2 at all, but only targets mitochondria. The effect of mubritinib as an anti-cancer drug is therefore only due to its activity against mitochondria. Digging deeper into the chemistry revealed the small parts of its chemical structure that was responsible for mubritinib’s toxicity against heart cells, the so-called toxic substructure. Another anti-cancer drug called carboxyamidotriazole also has the same toxic substructure. Carboxyamidotriazole is supposed to stop cells from taking up calcium ions, but a final set of experiments demonstrated that this drug also only acts by inhibiting mitochondria. Often there is not enough information about many drugs’ substructures, meaning off-target effects and toxicities cannot be predicted. The pharmaceutical industry will now be able to benefit from this new knowledge about the toxic substructures within some drugs. This research may also help patients who take mubritinib or carboxyamidotriazole, because their doctors will have to check for side effects on the heart more carefully.
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Affiliation(s)
- Zoe A Stephenson
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Robert F Harvey
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Kenneth R Pryde
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Sarah Mistry
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Rachel E Hardy
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Riccardo Serreli
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Injae Chung
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Timothy Eh Allen
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Mark Stoneley
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Marion MacFarlane
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Peter M Fischer
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Barrie Kellam
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
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24
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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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25
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Hirst J, Kunji ERS, Walker JE. Comment on "Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry". Science 2019; 366:eaaw9830. [PMID: 31699909 DOI: 10.1126/science.aaw9830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 10/09/2019] [Indexed: 02/02/2023]
Abstract
Chorev et al (Reports, 16 November 2018, p. 829) describe mass spectrometry on mitochondrial membrane proteins ionized directly from their native environment. However, the assignments made to measured masses are incorrect or inconclusive and lack experimental validation. The proteins are not in their "native" condition: They have been stripped of tightly bound lipids, and the complexes are fragmented or in physiologically irrelevant oligomeric states.
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Affiliation(s)
- Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - John E Walker
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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26
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Sokol K, Robinson WE, Oliveira AR, Zacarias S, Lee CY, Madden C, Bassegoda A, Hirst J, Pereira IA, Reisner E. Reversible and Selective Interconversion of Hydrogen and Carbon Dioxide into Formate by a Semiartificial Formate Hydrogenlyase Mimic. J Am Chem Soc 2019; 141:17498-17502. [PMID: 31638793 PMCID: PMC6838786 DOI: 10.1021/jacs.9b09575] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Indexed: 12/20/2022]
Abstract
The biological formate hydrogenlyase (FHL) complex links a formate dehydrogenase (FDH) to a hydrogenase (H2ase) and produces H2 and CO2 from formate via mixed-acid fermentation in Escherichia coli. Here, we describe an electrochemical and a colloidal semiartificial FHL system that consists of an FDH and a H2ase immobilized on conductive indium tin oxide (ITO) as an electron relay. These in vitro systems benefit from the efficient wiring of a highly active enzyme pair and allow for the reversible conversion of formate to H2 and CO2 under ambient temperature and pressure. The hybrid systems provide a template for the design of synthetic catalysts and surpass the FHL complex in vivo by storing and releasing H2 on demand by interconverting CO2/H2 and formate with minimal bias in either direction.
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Affiliation(s)
- Katarzyna
P. Sokol
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - William E. Robinson
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Ana R. Oliveira
- Instituto
de Tecnologia Química e Biológica António Xavier
(ITQB), Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Sonia Zacarias
- Instituto
de Tecnologia Química e Biológica António Xavier
(ITQB), Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Chong-Yong Lee
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Christopher Madden
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Arnau Bassegoda
- Medical
Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K.
| | - Judy Hirst
- Medical
Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K.
| | - Inês A.
C. Pereira
- Instituto
de Tecnologia Química e Biológica António Xavier
(ITQB), Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Erwin Reisner
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
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27
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Nagraj S, Hinton L, Praveen D, Kennedy S, Norton R, Hirst J. Women's and healthcare providers' perceptions of long-term complications associated with hypertension and diabetes in pregnancy: a qualitative study. BJOG 2019; 126 Suppl 4:34-42. [PMID: 31257668 PMCID: PMC6771686 DOI: 10.1111/1471-0528.15847] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2019] [Indexed: 12/27/2022]
Abstract
Objectives A diagnosis of hypertensive disorders during pregnancy (HDPs) or gestational diabetes mellitus (GDM) is highly predictive of women at increased risk of developing chronic hypertension, Type 2 diabetes, and cardiovascular disease. This study investigates perceptions of women and healthcare providers in rural India regarding these long‐term risks. Design Qualitative study using modified grounded theory. Setting Two states in rural India: Haryana and Andhra Pradesh. Population Pregnant and postpartum women, community health workers (CHWs), primary care physicians, obstetricians, laboratory technicians, and healthcare officials. Methods In‐depth interviews and focus group discussions explored: (1) priorities for high‐risk pregnant women; (2) detection and management of HDPs and GDM; (3) postpartum management, and (4) knowledge of long‐term sequelae of high‐risk conditions. A thematic analysis was undertaken. Results Seven focus group discussions and 11 in‐depth interviews (n = 71 participants) were performed. The key priority area for high‐risk pregnant women was anaemia. Blood pressure measurement was routinely embedded in antenatal care; however, postpartum follow up and knowledge of the long‐term complications were limited. GDM was not considered a common problem, although significant variations and challenges to GDM screening were identified. Knowledge of the long‐term sequelae of GDM with regard to an increased risk of Type 2 diabetes and cardiovascular disease among doctors was minimal. Conclusions There is a need for improved education, standardisation of testing and postpartum follow up of HDPs and GDM in rural Indian settings. Funding SN is supported by an MRC Clinical Research Training Fellowship (MR/R017182/1). The George Institute for Global Health Global Women's Health programme provided financial support for the research assistant and fieldwork costs in India. Tweetable abstract Improved education and postpartum care of women with hypertension and diabetes in pregnancy in rural India are needed to prevent long‐term risks. Improved education and postpartum care of women with hypertension and diabetes in pregnancy in rural India are needed to prevent long‐term risks.
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Affiliation(s)
- S Nagraj
- The George Institute for Global Health, University of Oxford, Oxford, UK.,Nuffield Department of Women's & Reproductive Health, Level 3 Women's Centre, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - L Hinton
- Nuffield Department of Primary Care Health Sciences, Radcliffe Observatory Quarter, University of Oxford, Oxford, UK
| | - D Praveen
- The George Institute for Global Health, Hyderabad, India
| | - S Kennedy
- Nuffield Department of Women's & Reproductive Health, Level 3 Women's Centre, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - R Norton
- The George Institute for Global Health, University of Oxford, Oxford, UK
| | - J Hirst
- The George Institute for Global Health, University of Oxford, Oxford, UK.,Nuffield Department of Women's & Reproductive Health, Level 3 Women's Centre, John Radcliffe Hospital, University of Oxford, Oxford, UK
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28
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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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29
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Abstract
In the mitochondrial inner membrane the respiratory enzymes associate to form supramolecular assemblies known as supercomplexes. The existence of supercomplexes is now widely accepted—but what functional or structural advantages, if any, do they confer?
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Affiliation(s)
- Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
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30
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Abstract
Mitochondrial respiratory supercomplexes, comprising complexes I, III, and IV, are the minimal functional units of the electron transport chain. Assembling the individual complexes into supercomplexes may stabilize them, provide greater spatiotemporal control of respiration, or, controversially, confer kinetic advantages through the sequestration of local quinone and cytochrome c pools (substrate channeling). Here, we have incorporated an alternative quinol oxidase (AOX) into mammalian heart mitochondrial membranes to introduce a competing pathway for quinol oxidation and test for channeling. AOX substantially increases the rate of NADH oxidation by O2 without affecting the membrane integrity, the supercomplexes, or NADH-linked oxidative phosphorylation. Therefore, the quinol generated in supercomplexes by complex I is reoxidized more rapidly outside the supercomplex by AOX than inside the supercomplex by complex III. Our results demonstrate that quinone and quinol diffuse freely in and out of supercomplexes: substrate channeling does not occur and is not required to support respiration.
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Affiliation(s)
- Justin G Fedor
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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31
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Agip ANA, Blaza JN, Bridges HR, Viscomi C, Rawson S, Muench SP, Hirst J. Cryo-EM structures of complex I from mouse heart mitochondria in two biochemically defined states. Nat Struct Mol Biol 2018; 25:548-556. [PMID: 29915388 PMCID: PMC6054875 DOI: 10.1038/s41594-018-0073-1] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/26/2018] [Indexed: 02/02/2023]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) uses the reducing potential of NADH to drive protons across the energy-transducing inner membrane and power oxidative phosphorylation in mammalian mitochondria. Recent cryo-EM analyses have produced near-complete models of all 45 subunits in the bovine, ovine and porcine complexes and have identified two states relevant to complex I in ischemia-reperfusion injury. Here, we describe the 3.3-Å structure of complex I from mouse heart mitochondria, a biomedically relevant model system, in the 'active' state. We reveal a nucleotide bound in subunit NDUFA10, a nucleoside kinase homolog, and define mechanistically critical elements in the mammalian enzyme. By comparisons with a 3.9-Å structure of the 'deactive' state and with known bacterial structures, we identify differences in helical geometry in the membrane domain that occur upon activation or that alter the positions of catalytically important charged residues. Our results demonstrate the capability of cryo-EM analyses to challenge and develop mechanistic models for mammalian complex I.
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Affiliation(s)
- Ahmed-Noor A Agip
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - James N Blaza
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Hannah R Bridges
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Carlo Viscomi
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Shaun Rawson
- School of Biomedical Sciences, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences and Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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32
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Molina JR, Sun Y, Protopopova M, Gera S, Bandi M, Bristow C, McAfoos T, Morlacchi P, Ackroyd J, Agip ANA, Al-Atrash G, Asara J, Bardenhagen J, Carrillo CC, Carroll C, Chang E, Ciurea S, Cross JB, Czako B, Deem A, Daver N, de Groot JF, Dong JW, Feng N, Gao G, Gay J, Do MG, Greer J, Giuliani V, Han J, Han L, Henry VK, Hirst J, Huang S, Jiang Y, Kang Z, Khor T, Konoplev S, Lin YH, Liu G, Lodi A, Lofton T, Ma H, Mahendra M, Matre P, Mullinax R, Peoples M, Petrocchi A, Rodriguez-Canale J, Serreli R, Shi T, Smith M, Tabe Y, Theroff J, Tiziani S, Xu Q, Zhang Q, Muller F, DePinho RA, Toniatti C, Draetta GF, Heffernan TP, Konopleva M, Jones P, Di Francesco ME, Marszalek JR. An inhibitor of oxidative phosphorylation exploits cancer vulnerability. Nat Med 2018; 24:1036-1046. [PMID: 29892070 DOI: 10.1038/s41591-018-0052-4] [Citation(s) in RCA: 540] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/27/2018] [Indexed: 12/19/2022]
Abstract
Metabolic reprograming is an emerging hallmark of tumor biology and an actively pursued opportunity in discovery of oncology drugs. Extensive efforts have focused on therapeutic targeting of glycolysis, whereas drugging mitochondrial oxidative phosphorylation (OXPHOS) has remained largely unexplored, partly owing to an incomplete understanding of tumor contexts in which OXPHOS is essential. Here, we report the discovery of IACS-010759, a clinical-grade small-molecule inhibitor of complex I of the mitochondrial electron transport chain. Treatment with IACS-010759 robustly inhibited proliferation and induced apoptosis in models of brain cancer and acute myeloid leukemia (AML) reliant on OXPHOS, likely owing to a combination of energy depletion and reduced aspartate production that leads to impaired nucleotide biosynthesis. In models of brain cancer and AML, tumor growth was potently inhibited in vivo following IACS-010759 treatment at well-tolerated doses. IACS-010759 is currently being evaluated in phase 1 clinical trials in relapsed/refractory AML and solid tumors.
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Affiliation(s)
- Jennifer R Molina
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yuting Sun
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Marina Protopopova
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sonal Gera
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Madhavi Bandi
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Christopher Bristow
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Timothy McAfoos
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Pietro Morlacchi
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Agilent Technologies Inc., Lexington, MA, USA
| | - Jeffrey Ackroyd
- Department of Cancer Imaging Systems, University of Texas MD Cancer Center, Houston, TX, USA
| | - Ahmed-Noor A Agip
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Cambridge, UK
| | - Gheath Al-Atrash
- Department of Stem Cell Transplantation and Cellular Therapy, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John Asara
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jennifer Bardenhagen
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Caroline C Carrillo
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Christopher Carroll
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Edward Chang
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Stefan Ciurea
- Department of Stem Cell Transplantation and Cellular Therapy, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jason B Cross
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Barbara Czako
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Angela Deem
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Naval Daver
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - John Frederick de Groot
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jian-Wen Dong
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ningping Feng
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Guang Gao
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jason Gay
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mary Geck Do
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jennifer Greer
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Virginia Giuliani
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jing Han
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lina Han
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Verlene K Henry
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Cambridge, UK
| | - Sha Huang
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yongying Jiang
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Zhijun Kang
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tin Khor
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sergej Konoplev
- Department of Hematopathology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yu-Hsi Lin
- Department of Cancer Imaging Systems, University of Texas MD Cancer Center, Houston, TX, USA
| | - Gang Liu
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Alessia Lodi
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX, USA
| | - Timothy Lofton
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Helen Ma
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mikhila Mahendra
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Polina Matre
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Robert Mullinax
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Michael Peoples
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Alessia Petrocchi
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jaime Rodriguez-Canale
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Riccardo Serreli
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Cambridge, UK
| | - Thomas Shi
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Melinda Smith
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yoko Tabe
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Next Generation Hematology Laboratory Medicine, Department of Laboratory Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Jay Theroff
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Stefano Tiziani
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX, USA
| | - Quanyun Xu
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Qi Zhang
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Florian Muller
- Department of Cancer Imaging Systems, University of Texas MD Cancer Center, Houston, TX, USA
| | - Ronald A DePinho
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Carlo Toniatti
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Giulio F Draetta
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Timothy P Heffernan
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Marina Konopleva
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Philip Jones
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - M Emilia Di Francesco
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Joseph R Marszalek
- Institute for Applied Cancer Science, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Center for Co-Clinical Trials, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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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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Varghese F, Blaza JN, Jones AJY, Jarman OD, Hirst J. Deleting the IF 1-like ζ subunit from Paracoccus denitrificans ATP synthase is not sufficient to activate ATP hydrolysis. Open Biol 2018; 8:170206. [PMID: 29367351 PMCID: PMC5795051 DOI: 10.1098/rsob.170206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [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: 08/31/2017] [Accepted: 12/26/2017] [Indexed: 11/12/2022] Open
Abstract
In oxidative phosphorylation, ATP synthases interconvert two forms of free energy: they are driven by the proton-motive force across an energy-transducing membrane to synthesize ATP and displace the ADP/ATP ratio from equilibrium. For thermodynamically efficient energy conversion they must be reversible catalysts. However, in many species ATP synthases are unidirectional catalysts (their rates of ATP hydrolysis are negligible), and in others mechanisms have evolved to regulate or minimize hydrolysis. Unidirectional catalysis by Paracoccus denitrificans ATP synthase has been attributed to its unique ζ subunit, which is structurally analogous to the mammalian inhibitor protein IF1 Here, we used homologous recombination to delete the ζ subunit from the P. denitrificans genome, and compared ATP synthesis and hydrolysis by the wild-type and knockout enzymes in inverted membrane vesicles and the F1-ATPase subcomplex. ATP synthesis was not affected by loss of the ζ subunit, and the rate of ATP hydrolysis increased by less than twofold, remaining negligible in comparison with the rates of the Escherichia coli and mammalian enzymes. Therefore, deleting the P. denitrificans ζ subunit is not sufficient to activate ATP hydrolysis. We close by considering our conclusions in the light of reversible catalysis and regulation in ATP synthase enzymes.
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Affiliation(s)
- Febin Varghese
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - James N Blaza
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Andrew J Y Jones
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Owen D Jarman
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
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Le Breton N, Wright JJ, Jones AJY, Salvadori E, Bridges HR, Hirst J, Roessler MM. Using Hyperfine Electron Paramagnetic Resonance Spectroscopy to Define the Proton-Coupled Electron Transfer Reaction at Fe-S Cluster N2 in Respiratory Complex I. J Am Chem Soc 2017; 139:16319-16326. [PMID: 29039928 DOI: 10.1021/jacs.7b09261] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Energy-transducing respiratory complex I (NADH:ubiquinone oxidoreductase) is one of the largest and most complicated enzymes in mammalian cells. Here, we used hyperfine electron paramagnetic resonance (EPR) spectroscopic methods, combined with site-directed mutagenesis, to determine the mechanism of a single proton-coupled electron transfer reaction at one of eight iron-sulfur clusters in complex I, [4Fe-4S] cluster N2. N2 is the terminal cluster of the enzyme's intramolecular electron-transfer chain and the electron donor to ubiquinone. Because of its position and pH-dependent reduction potential, N2 has long been considered a candidate for the elusive "energy-coupling" site in complex I at which energy generated by the redox reaction is used to initiate proton translocation. Here, we used hyperfine sublevel correlation (HYSCORE) spectroscopy, including relaxation-filtered hyperfine and single-matched resonance transfer (SMART) HYSCORE, to detect two weakly coupled exchangeable protons near N2. We assign the larger coupling with A(1H) = [-3.0, -3.0, 8.7] MHz to the exchangeable proton of a conserved histidine and conclude that the histidine is hydrogen-bonded to N2, tuning its reduction potential. The histidine protonation state responds to the cluster oxidation state, but the two are not coupled sufficiently strongly to catalyze a stoichiometric and efficient energy transduction reaction. We thus exclude cluster N2, despite its proton-coupled electron transfer chemistry, as the energy-coupling site in complex I. Our work demonstrates the capability of pulse EPR methods for providing detailed information on the properties of individual protons in even the most challenging of energy-converting enzymes.
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Affiliation(s)
- Nolwenn Le Breton
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
| | - John J Wright
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
| | - Andrew J Y Jones
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Enrico Salvadori
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom.,London Centre for Nanotechnology, University College London , 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Maxie M Roessler
- School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London, E1 4NS, United Kingdom
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Tyrakis PA, Yurkovich ME, Sciacovelli M, Papachristou EK, Bridges HR, Gaude E, Schreiner A, D'Santos C, Hirst J, Hernandez-Fernaud J, Springett R, Griffiths JR, Frezza C. Fumarate Hydratase Loss Causes Combined Respiratory Chain Defects. Cell Rep 2017; 21:1036-1047. [PMID: 29069586 PMCID: PMC5668630 DOI: 10.1016/j.celrep.2017.09.092] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [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: 09/15/2016] [Revised: 08/15/2017] [Accepted: 09/26/2017] [Indexed: 11/07/2022] Open
Abstract
Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid (TCA) cycle mutated in hereditary and sporadic cancers. Despite recent advances in understanding its role in tumorigenesis, the effects of FH loss on mitochondrial metabolism are still unclear. Here, we used mouse and human cell lines to assess mitochondrial function of FH-deficient cells. We found that human and mouse FH-deficient cells exhibit decreased respiration, accompanied by a varying degree of dysfunction of respiratory chain (RC) complex I and II. Moreover, we show that fumarate induces succination of key components of the iron-sulfur cluster biogenesis family of proteins, leading to defects in the biogenesis of iron-sulfur clusters that affect complex I function. We also demonstrate that suppression of complex II activity is caused by product inhibition due to fumarate accumulation. Overall, our work provides evidence that the loss of a single TCA cycle enzyme is sufficient to cause combined RC activity dysfunction.
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Affiliation(s)
- Petros A Tyrakis
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge CB2 0RE, UK
| | - Marie E Yurkovich
- Department of Biochemistry, University of Cambridge, Sanger Building, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Marco Sciacovelli
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge CB2 0XZ, UK
| | - Evangelia K Papachristou
- Proteomics Core Facility, Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge CB2 0RE, UK
| | - Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Edoardo Gaude
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge CB2 0XZ, UK
| | | | - Clive D'Santos
- Proteomics Core Facility, Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge CB2 0RE, UK
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Juan Hernandez-Fernaud
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK
| | - Roger Springett
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - John R Griffiths
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge CB2 0RE, UK
| | - Christian Frezza
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge Biomedical Campus, Box 197, Cambridge CB2 0XZ, UK.
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Robinson WE, Bassegoda A, Reisner E, Hirst J. Oxidation-State-Dependent Binding Properties of the Active Site in a Mo-Containing Formate Dehydrogenase. J Am Chem Soc 2017; 139:9927-9936. [PMID: 28635274 PMCID: PMC5532686 DOI: 10.1021/jacs.7b03958] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Molybdenum-containing formate dehydrogenase H from Escherichia coli (EcFDH-H) is a powerful model system for studies of the reversible reduction of CO2 to formate. However, the mechanism of FDH catalysis is currently under debate, and whether the primary Mo coordination sphere remains saturated or one of the ligands dissociates to allow direct substrate binding during turnover is disputed. Herein, we describe how oxidation-state-dependent changes at the active site alter its inhibitor binding properties. Using protein film electrochemistry, we show that formate oxidation by EcFDH-H is inhibited strongly and competitively by N3-, OCN-, SCN-, NO2-, and NO3-, whereas CO2 reduction is inhibited only weakly and not competitively. During catalysis, the Mo center cycles between the formal Mo(VI)═S and Mo(IV)-SH states, and by modeling chronoamperometry data recorded at different potentials and substrate and inhibitor concentrations, we demonstrate that both formate oxidation and CO2 reduction are inhibited by selective inhibitor binding to the Mo(VI)═S state. The strong dependence of inhibitor-binding affinity on both Mo oxidation state and inhibitor electron-donor strength indicates that inhibitors (and substrates) bind directly to the Mo center. We propose that inhibitors bind to the Mo following dissociation of a selenocysteine ligand to create a vacant coordination site for catalysis and close by considering the implications of our data for the mechanisms of formate oxidation and CO2 reduction.
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Affiliation(s)
- William E Robinson
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Arnau Bassegoda
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
| | - Erwin Reisner
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge , Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, U.K
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Molina J, Bandi M, Bardenhagen J, Bristow C, Carroll C, Chang E, Cross J, Daver N, Feng N, Gay J, Do MG, Greer J, Han J, Hirst J, Huang S, Jiang Y, Kang Z, Konopleva M, Liu G, Ma H, Matre P, McAfoos T, Meric-Bernstam F, Morlacchi P, Muller F, Protopopova M, Smith M, Sonal S, Sun Y, Theroff J, Viale A, Xu Q, Toniatti C, Draetta G, Jones P, Francesco MED, Marszalek JR. Abstract 4971: IACS-010759, a novel inhibitor of complex I in Phase I clinical development to target OXPHOS dependent tumors. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-4971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Tumor cells depend on both glycolysis and oxidative phosphorylation (OXPHOS) for energy and biomass production to support cell proliferation. Recent data has demonstrated a dependence of various tumor types on mitochondrial OXPHOS, which represents an exciting therapeutic opportunity. Through an extensive medicinal chemistry campaign, IACS-010759 was identified as a potent, selective inhibitor of complex I of the electron transport chain, which is orally bioavailable and has excellent PK and physicochemical properties in preclinical species. Our group and others have demonstrated that AML, plus subsets of glioblastoma, neuroblastoma, lymphoma, melanoma, triple negative breast cancer (TNBC) and pancreatic cancer (PDAC) are highly dependent on OXPHOS to meet energy and biomass demands. Treatment of multiple cell lines and patient derived xenograft (PDX) models in several cancer types with IACS-010759 led to a robust decrease in cell viability and often an increase in apoptosis with EC50 values between 1 nM - 50 nM across multiple lines. Through a series of mechanistic studies we established that IACS-10759 blocks complex I of the electron transport at the quinone binding site. Mechanistically, response to IACS-010759 was associated with induction of a metabolic imbalances that negatively impacted energy homeostasis, aspartate biosynthesis, and NTP production due to reduced conversion of NADH to NAD+ by complex I, decreased ATP production, TCA cycle flux and nucleotide biosynthesis. Tumor growth inhibition and regression have been observed in molecularly defined subsets of TNBC and PDAC PDX xenograft models treated with IACS-010759, indicating that subsets of these indications are dependent on OXPHOS. Furthermore, treating TNBC or PDAC PDX models post-chemotherapy with IACS-010759 extends progression free survival, consistent with IACS-010759 targeting recently described metabolically adapted residual tumor cells. In orthotopic xenograft models of primary AML cells, daily oral treatment with 1-7.5 mg/kg IACS-010759 extended the median survival. Efficacy was paralleled by robust modulation of OCR, aspartate, and a gene signature levels. Therefore, these readouts (OCR, aspartate and a nanostring geneset) have been validated for use as exploratory clinical biology of response endpoints. In parallel, completion of preclinical chemistry, manufacturing and control (CMC) as well as GLP safety and tolerability studies with IACS-010759 in multiple species have enabled the selection of a clinical entry dose. As a result of the robust response in multiple cell lines, primary patient samples, and efficacy in PDX models, a Phase I clinical trial in relapsed, refractory AML was initiated in October 2016, with a parallel trial in solid tumors expected to initiate in early 2017. Initial results from the on-going AML trial will be disclosed.
Citation Format: Jennifer Molina, Madhavi Bandi, Jennifer Bardenhagen, Christopher Bristow, Christopher Carroll, Edward Chang, Jason Cross, Naval Daver, Ningping Feng, Jason Gay, Mary Geck Do, Jennifer Greer, Jing Han, Judy Hirst, Sha Huang, Yongying Jiang, Zhijun Kang, Marina Konopleva, Gang Liu, Helen Ma, Polina Matre, Timothy McAfoos, Funda Meric-Bernstam, Pietro Morlacchi, Florian Muller, Marina Protopopova, Melinda Smith, Sonal Sonal, Yuting Sun, Jay Theroff, Andrea Viale, Quanyun Xu, Carlo Toniatti, Giulio Draetta, Philip Jones, M. Emilia Di Francesco, Joseph R. Marszalek. IACS-010759, a novel inhibitor of complex I in Phase I clinical development to target OXPHOS dependent tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4971. doi:10.1158/1538-7445.AM2017-4971
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jason Gay
- 1UT MD Anderson Cancer Center, Houston, TX
| | | | | | - Jing Han
- 1UT MD Anderson Cancer Center, Houston, TX
| | - Judy Hirst
- 2MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Sha Huang
- 1UT MD Anderson Cancer Center, Houston, TX
| | | | | | | | - Gang Liu
- 1UT MD Anderson Cancer Center, Houston, TX
| | - Helen Ma
- 1UT MD Anderson Cancer Center, Houston, TX
| | | | | | | | | | | | | | | | | | - Yuting Sun
- 1UT MD Anderson Cancer Center, Houston, TX
| | | | | | - Quanyun Xu
- 1UT MD Anderson Cancer Center, Houston, TX
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Abstract
Respiratory chain dysfunction plays an important role in human disease and aging. It is now well established that the individual respiratory complexes can be organized into supercomplexes, and structures for these macromolecular assemblies, determined by electron cryo-microscopy, have been described recently. Nevertheless, the reason why supercomplexes exist remains an enigma. The widely held view that they enhance catalysis by channeling substrates is challenged by both structural and biophysical information. Here, we evaluate and discuss data and hypotheses on the structures, roles, and assembly of respiratory-chain supercomplexes and propose a future research agenda to address unanswered questions.
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Affiliation(s)
- Dusanka Milenkovic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - James N Blaza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden.
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
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40
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Jones AJY, Blaza JN, Varghese F, Hirst J. Respiratory Complex I in Bos taurus and Paracoccus denitrificans Pumps Four Protons across the Membrane for Every NADH Oxidized. J Biol Chem 2017; 292:4987-4995. [PMID: 28174301 PMCID: PMC5377811 DOI: 10.1074/jbc.m116.771899] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [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: 12/09/2016] [Revised: 01/27/2017] [Indexed: 11/22/2022] Open
Abstract
Respiratory complex I couples electron transfer between NADH and ubiquinone to proton translocation across an energy-transducing membrane to support the proton-motive force that drives ATP synthesis. The proton-pumping stoichiometry of complex I (i.e. the number of protons pumped for each two electrons transferred) underpins all mechanistic proposals. However, it remains controversial and has not been determined for any of the bacterial enzymes that are exploited as model systems for the mammalian enzyme. Here, we describe a simple method for determining the proton-pumping stoichiometry of complex I in inverted membrane vesicles under steady-state ADP-phosphorylating conditions. Our method exploits the rate of ATP synthesis, driven by oxidation of NADH or succinate with different sections of the respiratory chain engaged in catalysis as a proxy for the rate of proton translocation and determines the stoichiometry of complex I by reference to the known stoichiometries of complexes III and IV. Using vesicles prepared from mammalian mitochondria (from Bos taurus) and from the bacterium Paracoccus denitrificans, we show that four protons are pumped for every two electrons transferred in both cases. By confirming the four-proton stoichiometry for mammalian complex I and, for the first time, demonstrating the same value for a bacterial complex, we establish the utility of P. denitrificans complex I as a model system for the mammalian enzyme. P. denitrificans is the first system described in which mutagenesis in any complex I core subunit may be combined with quantitative proton-pumping measurements for mechanistic studies.
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Affiliation(s)
- Andrew J Y Jones
- From the Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom
| | - James N Blaza
- From the Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom
| | - Febin Varghese
- From the Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom
| | - Judy Hirst
- From the Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom
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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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Wright JJ, Salvadori E, Bridges HR, Hirst J, Roessler MM. Small-volume potentiometric titrations: EPR investigations of Fe-S cluster N2 in mitochondrial complex I. J Inorg Biochem 2016; 162:201-206. [DOI: 10.1016/j.jinorgbio.2016.04.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
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Abstract
Complex I (NADH:ubiquinone oxidoreductase), one of the largest membrane-bound enzymes in the cell, powers ATP synthesis in mammalian mitochondria by using the reducing potential of NADH to drive protons across the inner membrane. Mammalian complex I1 contains 45 subunits, comprising 14 core subunits that house the catalytic machinery and are conserved from bacteria to humans, and a mammalian-specific cohort of 31 supernumerary subunits1,2. Knowledge about the structures and functions of the supernumerary subunits is fragmentary. Here, we describe a 4.2 Å resolution single-particle cryoEM structure of complex I from Bos taurus. We locate and model all 45 subunits to provide the entire structure of the mammalian complex. Furthermore, computational sorting of the particles identified different structural classes, related by subtle domain movements, which reveal conformationally-dynamic regions and match biochemical descriptions of the ‘active-to-deactive’ enzyme transition that occurs during hypoxia3,4. Thus, our structures provide a foundation for understanding complex I assembly5 and the effects of mutations that cause clinically-relevant complex I dysfunctions6, insights into the structural and functional roles of the supernumerary subunits, and new information on the mechanism and regulation of catalysis.
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Affiliation(s)
- Jiapeng Zhu
- MRC Mitochondrial Biology Unit, 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, Hills Road, Cambridge CB2 0XY, UK
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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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Jones AJY, Blaza JN, Bridges HR, May B, Moore AL, Hirst J. A Self-Assembled Respiratory Chain that Catalyzes NADH Oxidation by Ubiquinone-10 Cycling between Complex I and the Alternative Oxidase. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201507332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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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Jones AJY, Blaza JN, Bridges HR, May B, Moore AL, Hirst J. A Self-Assembled Respiratory Chain that Catalyzes NADH Oxidation by Ubiquinone-10 Cycling between Complex I and the Alternative Oxidase. Angew Chem Int Ed Engl 2015; 55:728-31. [PMID: 26592861 PMCID: PMC4954055 DOI: 10.1002/anie.201507332] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/28/2015] [Indexed: 12/05/2022]
Abstract
Complex I is a crucial respiratory enzyme that conserves the energy from NADH oxidation by ubiquinone‐10 (Q10) in proton transport across a membrane. Studies of its energy transduction mechanism are hindered by the extreme hydrophobicity of Q10, and they have so far relied on native membranes with many components or on hydrophilic Q10 analogues that partition into membranes and undergo side reactions. Herein, we present a self‐assembled system without these limitations: proteoliposomes containing mammalian complex I, Q10, and a quinol oxidase (the alternative oxidase, AOX) to recycle Q10H2 to Q10. AOX is present in excess, so complex I is completely rate determining and the Q10 pool is kept oxidized under steady‐state catalysis. The system was used to measure a fully‐defined KM value for Q10. The strategy is suitable for any enzyme with a hydrophobic quinone/quinol substrate, and could be used to characterize hydrophobic inhibitors with potential applications as pharmaceuticals, pesticides, or fungicides.
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Affiliation(s)
- Andrew J Y Jones
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY (UK)
| | - James N Blaza
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY (UK)
| | - Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY (UK)
| | - Benjamin May
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG (UK)
| | - Anthony L Moore
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG (UK)
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY (UK).
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Varghese F, Atcheson E, Bridges HR, Hirst J. Characterization of clinically identified mutations in NDUFV1, the flavin-binding subunit of respiratory complex I, using a yeast model system. Hum Mol Genet 2015; 24:6350-60. [PMID: 26345448 PMCID: PMC4614703 DOI: 10.1093/hmg/ddv344] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/18/2015] [Indexed: 02/02/2023] Open
Abstract
Dysfunctions in mitochondrial complex I (NADH:ubiquinone oxidoreductase) are both genetically and clinically highly diverse and a major cause of human mitochondrial diseases. The genetic determinants of individual clinical cases are increasingly being described, but how these genetic defects affect complex I on the molecular and cellular level, and have different clinical consequences in different individuals, is little understood. Furthermore, without molecular-level information innocent genetic variants may be misassigned as pathogenic. Here, we have used a yeast model system (Yarrowia lipolytica) to study the molecular consequences of 16 single amino acid substitutions, classified as pathogenic, in the NDUFV1 subunit of complex I. NDUFV1 binds the flavin cofactor that oxidizes NADH and is the site of complex I-mediated reactive oxygen species production. Seven mutations caused loss of complex I expression, suggesting they are detrimental but precluding further study. In two variants complex I was fully assembled but did not contain any flavin, and four mutations led to functionally compromised enzymes. Our study provides a molecular rationale for assignment of all these variants as pathogenic. However, three variants provided complex I that was functionally equivalent to the wild-type enzyme, challenging their assignment as pathogenic. By combining structural, bioinformatic and functional data, a simple scoring system for the initial evaluation of future NDUFV1 variants is proposed. Overall, our results broaden understanding of how mutations in this centrally important core subunit of complex I affect its function and provide a basis for understanding the role of NDUFV1 mutations in mitochondrial dysfunction.
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Affiliation(s)
- Febin Varghese
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Erwan Atcheson
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Hannah R Bridges
- 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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Bassegoda A, Madden C, Wakerley DW, Reisner E, Hirst J. Correction to “Reversible Interconversion of CO2 and Formate by a Molybdenum-Containing Formate Dehydrogenase”. J Am Chem Soc 2015; 137:4592. [DOI: 10.1021/jacs.5b01967] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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50
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Abstract
Complex I (NADH:ubiquinone oxidoreductase) is essential for oxidative phosphorylation in mammalian mitochondria. It couples electron transfer from NADH to ubiquinone with proton translocation across the energy-transducing inner membrane, providing electrons for respiration and driving ATP synthesis. Mammalian complex I contains 44 different nuclear- and mitochondrial-encoded subunits, with a combined mass of 1 MDa. The 14 conserved 'core' subunits have been structurally defined in the minimal, bacterial complex, but the structures and arrangement of the 30 'supernumerary' subunits are unknown. Here we describe a 5 Å resolution structure of complex I from Bos taurus heart mitochondria, a close relative of the human enzyme, determined by single-particle electron cryo-microscopy. We present the structures of the mammalian core subunits that contain eight iron-sulphur clusters and 60 transmembrane helices, identify 18 supernumerary transmembrane helices, and assign and model 14 supernumerary subunits. Thus, we considerably advance knowledge of the structure of mammalian complex I and the architecture of its supernumerary ensemble around the core domains. Our structure provides insights into the roles of the supernumerary subunits in regulation, assembly and homeostasis, and a basis for understanding the effects of mutations that cause a diverse range of human diseases.
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Affiliation(s)
- Kutti R Vinothkumar
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Jiapeng Zhu
- MRC Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, Wellcome Trust / MRC Building, Hills Road, Cambridge, CB2 0XY, UK
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