51
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Formate hydrogenlyase, formic acid translocation and hydrogen production: dynamic membrane biology during fermentation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148919. [PMID: 36152681 DOI: 10.1016/j.bbabio.2022.148919] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/19/2022] [Accepted: 09/19/2022] [Indexed: 12/14/2022]
Abstract
Formate hydrogenlyase-1 (FHL-1) is a complex-I-like enzyme that is commonly found in gram-negative bacteria. The enzyme comprises a peripheral arm and a membrane arm but is not involved in quinone reduction. Instead, FHL-1 couples formate oxidation to the reduction of protons to molecular hydrogen (H2). Escherichia coli produces FHL-1 under fermentative conditions where it serves to detoxify formic acid in the environment. The membrane biology and bioenergetics surrounding E. coli FHL-1 have long held fascination. Here, we review recent work on understanding the molecular basis of formic acid efflux and influx. We also consider the structure and function of E. coli FHL-1, its relationship with formate transport, and pay particular attention to the molecular interface between the peripheral arm and the membrane arm. Finally, we highlight the interesting phenotype of genetic mutation of the ND1 Loop, which is located at that interface.
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52
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Maldonado M, Fan Z, Abe KM, Letts JA. Plant-specific features of respiratory supercomplex I + III 2 from Vigna radiata. NATURE PLANTS 2023; 9:157-168. [PMID: 36581760 PMCID: PMC9873571 DOI: 10.1038/s41477-022-01306-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/08/2022] [Indexed: 05/07/2023]
Abstract
The last steps of cellular respiration-an essential metabolic process in plants-are carried out by mitochondrial oxidative phosphorylation. This process involves a chain of multi-subunit membrane protein complexes (complexes I-V) that form higher-order assemblies called supercomplexes. Although supercomplexes are the most physiologically relevant form of the oxidative phosphorylation complexes, their functions and structures remain mostly unknown. Here we present the cryogenic electron microscopy structure of the supercomplex I + III2 from Vigna radiata (mung bean). The structure contains the full subunit complement of complex I, including a newly assigned, plant-specific subunit. It also shows differences in the mitochondrial processing peptidase domain of complex III2 relative to a previously determined supercomplex with complex IV. The supercomplex interface, while reminiscent of that in other organisms, is plant specific, with a major interface involving complex III2's mitochondrial processing peptidase domain and no participation of complex I's bridge domain. The complex I structure suggests that the bridge domain sets the angle between the enzyme's two arms, limiting large-scale conformational changes. Moreover, complex I's catalytic loops and its response in active-to-deactive assays suggest that, in V. radiata, the resting complex adopts a non-canonical state and can sample deactive- or open-like conformations even in the presence of substrate. This study widens our understanding of the possible conformations and behaviour of complex I and supercomplex I + III2. Further studies of complex I and its supercomplexes in diverse organisms are needed to determine the universal and clade-specific mechanisms of respiration.
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Affiliation(s)
- M Maldonado
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
- Department of Plant Biology, University of California, Davis, CA, USA.
| | - Z Fan
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - K M Abe
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - J A Letts
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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53
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Terashi G, Wang X, Kihara D. Protein model refinement for cryo-EM maps using AlphaFold2 and the DAQ score. Acta Crystallogr D Struct Biol 2023; 79:10-21. [PMID: 36601803 PMCID: PMC9815095 DOI: 10.1107/s2059798322011676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
As more protein structure models have been determined from cryogenic electron microscopy (cryo-EM) density maps, establishing how to evaluate the model accuracy and how to correct models in cases where they contain errors is becoming crucial to ensure the quality of the structural models deposited in the public database, the PDB. Here, a new protocol is presented for evaluating a protein model built from a cryo-EM map and applying local structure refinement in the case where the model has potential errors. Firstly, model evaluation is performed using a deep-learning-based model-local map assessment score, DAQ, that has recently been developed. The subsequent local refinement is performed by a modified AlphaFold2 procedure, in which a trimmed template model and a trimmed multiple sequence alignment are provided as input to control which structure regions to refine while leaving other more confident regions of the model intact. A benchmark study showed that this protocol, DAQ-refine, consistently improves low-quality regions of the initial models. Among 18 refined models generated for an initial structure, DAQ shows a high correlation with model quality and can identify the best accurate model for most of the tested cases. The improvements obtained by DAQ-refine were on average larger than other existing methods.
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Affiliation(s)
- Genki Terashi
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xiao Wang
- Department of Computer Science, Purdue University, West Lafayette, IN 47907, USA
| | - Daisuke Kihara
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA,Department of Computer Science, Purdue University, West Lafayette, IN 47907, USA,Correspondence e-mail:
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54
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Wikström M, Djurabekova A, Sharma V. On the role of ubiquinone in the proton translocation mechanism of respiratory complex I. FEBS Lett 2023; 597:224-236. [PMID: 36180980 DOI: 10.1002/1873-3468.14506] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 01/26/2023]
Abstract
Complex I converts oxidoreduction energy into a proton electrochemical gradient across the inner mitochondrial or bacterial cell membrane. This gradient is the primary source of energy for aerobic synthesis of ATP. Oxidation of reduced nicotinamide adenine dinucleotide (NADH) by ubiquinone (Q) yields NAD+ and ubiquinol (QH2 ), which is tightly coupled to translocation of four protons from the negatively to the positively charged side of the membrane. Electrons from NADH oxidation reach the iron-sulfur centre N2 positioned near the bottom of a tunnel that extends circa 30 Å from the membrane domain into the hydrophilic domain of the complex. The tunnel is occupied by ubiquinone, which can take a distal position near the N2 centre or proximal positions closer to the membrane. Here, we review important structural, kinetic and thermodynamic properties of ubiquinone that define its role in complex I function. We suggest that this function exceeds that of a mere substrate or electron acceptor and propose that ubiquinone may be the redox element of complex I coupling electron transfer to proton translocation.
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Affiliation(s)
- Mårten Wikström
- HiLIFE Institute of Biotechnology, University of Helsinki, Finland
| | | | - Vivek Sharma
- HiLIFE Institute of Biotechnology, University of Helsinki, Finland.,Department of Physics, University of Helsinki, Finland
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55
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Stuchebrukhov AA, Hayashi T. Single protonation of the reduced quinone in respiratory complex I drives four-proton pumping. FEBS Lett 2023; 597:237-245. [PMID: 36251339 PMCID: PMC9877130 DOI: 10.1002/1873-3468.14518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/02/2022] [Accepted: 10/03/2022] [Indexed: 01/29/2023]
Abstract
Complex I is a key proton-pumping enzyme in bacterial and mitochondrial respiratory electron transport chains. Using quantum chemistry and electrostatic calculations, we have examined the pKa of the reduced quinone QH-/QH2 in the catalytic cavity of complex I. We find that pKa (QH-/QH2) is very high, above 20. This means that the energy of a single protonation reaction of the doubly reduced quinone (i.e. the reduced semiquinone QH-) is sufficient to drive four protons across the membrane with a potential of 180 mV. Based on these calculations, we propose a possible scheme of redox-linked proton pumping by complex I. The model explains how the energy of the protonation reaction can be divided equally among four pumping units of the pump, and how a single proton can drive translocation of four additional protons in multiple pumping blocks.
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Affiliation(s)
| | - Tomoyuki Hayashi
- Department of Chemistry, University of California, Davis, CA 95616
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56
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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] [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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57
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Bennett CF, Latorre-Muro P, Puigserver P. Mechanisms of mitochondrial respiratory adaptation. Nat Rev Mol Cell Biol 2022; 23:817-835. [PMID: 35804199 PMCID: PMC9926497 DOI: 10.1038/s41580-022-00506-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2022] [Indexed: 02/07/2023]
Abstract
Mitochondrial energetic adaptations encompass a plethora of conserved processes that maintain cell and organismal fitness and survival in the changing environment by adjusting the respiratory capacity of mitochondria. These mitochondrial responses are governed by general principles of regulatory biology exemplified by changes in gene expression, protein translation, protein complex formation, transmembrane transport, enzymatic activities and metabolite levels. These changes can promote mitochondrial biogenesis and membrane dynamics that in turn support mitochondrial respiration. The main regulatory components of mitochondrial energetic adaptation include: the transcription coactivator peroxisome proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC1α) and associated transcription factors; mTOR and endoplasmic reticulum stress signalling; TOM70-dependent mitochondrial protein import; the cristae remodelling factors, including mitochondrial contact site and cristae organizing system (MICOS) and OPA1; lipid remodelling; and the assembly and metabolite-dependent regulation of respiratory complexes. These adaptive molecular and structural mechanisms increase respiration to maintain basic processes specific to cell types and tissues. Failure to execute these regulatory responses causes cell damage and inflammation or senescence, compromising cell survival and the ability to adapt to energetically demanding conditions. Thus, mitochondrial adaptive cellular processes are important for physiological responses, including to nutrient availability, temperature and physical activity, and their failure leads to diseases associated with mitochondrial dysfunction such as metabolic and age-associated diseases and cancer.
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Affiliation(s)
- Christopher F Bennett
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Pedro Latorre-Muro
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Pere Puigserver
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
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58
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Laube E, Meier-Credo J, Langer JD, Kühlbrandt W. Conformational changes in mitochondrial complex I of the thermophilic eukaryote Chaetomium thermophilum. SCIENCE ADVANCES 2022; 8:eadc9952. [PMID: 36427319 PMCID: PMC9699679 DOI: 10.1126/sciadv.adc9952] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 10/07/2022] [Indexed: 05/23/2023]
Abstract
Mitochondrial complex I is a redox-driven proton pump that generates proton-motive force across the inner mitochondrial membrane, powering oxidative phosphorylation and ATP synthesis in eukaryotes. We report the structure of complex I from the thermophilic fungus Chaetomium thermophilum, determined by cryoEM up to 2.4-Å resolution. We show that the complex undergoes a transition between two conformations, which we refer to as state 1 and state 2. The conformational switch is manifest in a twisting movement of the peripheral arm relative to the membrane arm, but most notably in substantial rearrangements of the Q-binding cavity and the E-channel, resulting in a continuous aqueous passage from the E-channel to subunit ND5 at the far end of the membrane arm. The conformational changes in the complex interior resemble those reported for mammalian complex I, suggesting a highly conserved, universal mechanism of coupling electron transport to proton pumping.
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Affiliation(s)
- Eike Laube
- Max-Planck-Institute of Biophysics, Frankfurt 60438, Germany
| | - Jakob Meier-Credo
- Max-Planck-Institute of Biophysics, Frankfurt 60438, Germany
- Max-Planck-Institute for Brain Research, Frankfurt 60438, Germany
| | - Julian D. Langer
- Max-Planck-Institute of Biophysics, Frankfurt 60438, Germany
- Max-Planck-Institute for Brain Research, Frankfurt 60438, Germany
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59
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Kurelac I, Cavina B, Sollazzo M, Miglietta S, Fornasa A, De Luise M, Iorio M, Lama E, Traversa D, Nasiri HR, Ghelli A, Musiani F, Porcelli AM, Iommarini L, Gasparre G. NDUFS3 knockout cancer cells and molecular docking reveal specificity and mode of action of anti-cancer respiratory complex I inhibitors. Open Biol 2022; 12:220198. [PMID: 36349549 PMCID: PMC9653258 DOI: 10.1098/rsob.220198] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Inhibition of respiratory complex I (CI) is becoming a promising anti-cancer strategy, encouraging the design and the use of inhibitors, whose mechanism of action, efficacy and specificity remain elusive. As CI is a central player of cellular bioenergetics, a finely tuned dosing of targeting drugs is required to avoid side effects. We compared the specificity and mode of action of CI inhibitors metformin, BAY 87-2243 and EVP 4593 using cancer cell models devoid of CI. Here we show that both BAY 87-2243 and EVP 4593 were selective, while the antiproliferative effects of metformin were considerably independent from CI inhibition. Molecular docking predictions indicated that the high efficiency of BAY 87-2243 and EVP 4593 may derive from the tight network of bonds in the quinone binding pocket, although in different sites. Most of the amino acids involved in such interactions are conserved across species and only rarely found mutated in human. Our data make a case for caution when referring to metformin as a CI-targeting compound, and highlight the need for dosage optimization and careful evaluation of molecular interactions between inhibitors and the holoenzyme.
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Affiliation(s)
- Ivana Kurelac
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy,Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy
| | - Beatrice Cavina
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Manuela Sollazzo
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Stefano Miglietta
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Agnese Fornasa
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Monica De Luise
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy,Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy
| | - Maria Iorio
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Eleonora Lama
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Daniele Traversa
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Hamid Razi Nasiri
- Department of Cellular Microbiology, University Hohenheim, Stuttgart, Germany
| | - Anna Ghelli
- Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy,Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Francesco Musiani
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Anna Maria Porcelli
- Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy,Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy,Interdepartmental Centre for Industrial Research ‘Scienze della Vita e Tecnologie per la Salute’, University of Bologna, Bologna, Italy
| | - Luisa Iommarini
- Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy,Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Giuseppe Gasparre
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy,Centre for Applied Biomedical Research (CRBA), University of Bologna, Bologna, Italy
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60
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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] [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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61
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Alkhaldi HA, Vik SB. Subunits E-F-G of E. coli Complex I can form an active complex when expressed alone, but in time-delayed assembly co-expression of B-CD-E-F-G is optimal. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148593. [PMID: 35850264 PMCID: PMC9783743 DOI: 10.1016/j.bbabio.2022.148593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/15/2022] [Accepted: 07/11/2022] [Indexed: 12/27/2022]
Abstract
Respiratory Complex I from E. coli is a proto-type of the mitochondrial enzyme, consisting of a 6-subunit peripheral arm (B-CD-E-F-G-I) and a 7-subunit membrane arm. When subunits E-F-G (N-module), were expressed alone they formed an active complex as determined by co-immunoprecipitation and native gel electrophoresis. When co-expressed with subunits B and CD, only a complex of E-F-G was found. When these five subunits were co-expressed with subunit I and two membrane subunits, A and H, a complex of B-CD-E-F-G-I was membrane-bound, constituting the N- and Q-modules. Assembly of Complex I was also followed by splitting the genes between two plasmids, in three different groupings, and expressing them simultaneously, or with time-delay of expression from one plasmid. When the B-CD-E-F-G genes were co-expressed after a time-delay, assembly was over 90 % of that when the whole operon was expressed together. In summary, E-F-G was the only soluble subcomplex detected in these studies, but assembly was not optimal when these subunits were expressed either first or last. Co-expression of subunits B and CD with E-F-G provided a higher level of assembly, indicating that integrated assembly of N- and Q-modules provides a more efficient pathway.
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Affiliation(s)
- Hind A Alkhaldi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Steven B Vik
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA.
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62
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Grivennikova VG, Khailova LS, Zharova TV, Kotova EA, Antonenko YN. Inhibition of respiratory complex I by 6-ketocholestanol: Relevance to recoupling action in mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148594. [PMID: 35850263 DOI: 10.1016/j.bbabio.2022.148594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
6-Ketocholestanol (kCh) is known as a mitochondrial recoupler, i.e. it abolishes uncoupling of mitochondria by such potent agents as carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 3,5-di(tert-butyl)-4-hydroxybenzylidenemalononitril (SF6847) [Starkov et al., 1997]. Here, we report data on the kCh-induced inhibition of both NADH-oxidase and NADH-ubiquinone oxidoreductase activities of the respiratory complex I in bovine heart submitochondrial particles (SMP). Based on the absence of such inhibition with hexaammineruthenium (III) (HAR) as the complex I electron acceptor, the kCh effect could be associated with the ubiquinone-binding centre of this respiratory enzyme. In isolated rat liver mitochondria (RLM), kCh inhibited oxygen consumption with the glutamate/malate, substrates of NAD-linked dehydrogenases, while no inhibition of RLM respiration was observed with succinate, in agreement with the absence of the kCh effect on the succinate oxidase activity in SMP. Three kCh analogs (cholesterol, 6α-hydroxycholesterol, and 5α,6α-epoxycholesterol) exhibited no effect on the NADH oxidase activities in both SMP and RLM. Importantly, the kCh analogs were ineffective in the recoupling of RLM treated with CCCP or SF6847. Therefore, interaction of kCh with the complex I may be involved in the kCh-mediated mitochondrial recoupling.
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Affiliation(s)
- Vera G Grivennikova
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119992, Russian Federation.
| | - Ljudmila S Khailova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Tatyana V Zharova
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119992, Russian Federation
| | - Elena A Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation.
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63
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Oppermann S, Seng K, Shweich L, Friedrich T. The gene order in the nuo-operon is not essential for the assembly of E. coli complex I. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148592. [PMID: 35863511 DOI: 10.1016/j.bbabio.2022.148592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/25/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Energy-converting NADH: ubiquinone oxidoreductase, respiratory complex I, plays an important role in cellular energy metabolism. Bacterial complex I is generally composed of 14 different subunits, seven of which are membranous and the other seven are globular proteins. They are encoded by the nuo-operon, whose gene order is strictly conserved in bacteria. The operon starts with nuoA encoding a membranous subunit followed by genes encoding globular subunits. To test the idea that NuoA acts as a seed to initiate the assembly of the complex in the membrane, we generated mutants that either lacked nuoA or contain nuoA at a different position within the operon. To enable the detection of putative assembly intermediates, the globular subunit NuoF and the membranous subunit NuoM were individually decorated with the fluorescent protein mCherry. Deletion of nuoA led to the assembly of an inactive complex in the membrane containing NuoF and NuoM. Re-arrangement of nuoA within the nuo-operon led to a slightly diminished amount of complex I in the membrane that was fully active. Thus, nuoA but not its distinct position in the operon is required for the assembly of E. coli complex I. Furthermore, we detected a previously unknown assembly intermediate in the membrane containing NuoM that is present in greater amounts than complex I.
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Affiliation(s)
- S Oppermann
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - K Seng
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - L Shweich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - T Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
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64
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Pei J, Zhang J, Cong Q. Human mitochondrial protein complexes revealed by large-scale coevolution analysis and deep learning-based structure modeling. Bioinformatics 2022; 38:4301-4311. [PMID: 35881696 DOI: 10.1093/bioinformatics/btac527] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 05/27/2022] [Accepted: 07/22/2022] [Indexed: 12/24/2022] Open
Abstract
MOTIVATION Recent development of deep-learning methods has led to a breakthrough in the prediction accuracy of 3D protein structures. Extending these methods to protein pairs is expected to allow large-scale detection of protein-protein interactions (PPIs) and modeling protein complexes at the proteome level. RESULTS We applied RoseTTAFold and AlphaFold, two of the latest deep-learning methods for structure predictions, to analyze coevolution of human proteins residing in mitochondria, an organelle of vital importance in many cellular processes including energy production, metabolism, cell death and antiviral response. Variations in mitochondrial proteins have been linked to a plethora of human diseases and genetic conditions. RoseTTAFold, with high computational speed, was used to predict the coevolution of about 95% of mitochondrial protein pairs. Top-ranked pairs were further subject to modeling of the complex structures by AlphaFold, which also produced contact probability with high precision and in many cases consistent with RoseTTAFold. Most top-ranked pairs with high contact probability were supported by known PPIs and/or similarities to experimental structural complexes. For high-scoring pairs without experimental complex structures, our coevolution analyses and structural models shed light on the details of their interfaces, including CHCHD4-AIFM1, MTERF3-TRUB2, FMC1-ATPAF2 and ECSIT-NDUFAF1. We also identified novel PPIs (PYURF-NDUFAF5, LYRM1-MTRF1L and COA8-COX10) for several proteins without experimentally characterized interaction partners, leading to predictions of their molecular functions and the biological processes they are involved in. AVAILABILITY AND IMPLEMENTATION Data of mitochondrial proteins and their interactions are available at: http://conglab.swmed.edu/mitochondria. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Jimin Pei
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jing Zhang
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Qian Cong
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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65
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Steinhilper R, Höff G, Heider J, Murphy BJ. Structure of the membrane-bound formate hydrogenlyase complex from Escherichia coli. Nat Commun 2022; 13:5395. [PMID: 36104349 PMCID: PMC9474812 DOI: 10.1038/s41467-022-32831-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/08/2022] [Indexed: 01/30/2023] Open
Abstract
The prototypical hydrogen-producing enzyme, the membrane-bound formate hydrogenlyase (FHL) complex from Escherichia coli, links formate oxidation at a molybdopterin-containing formate dehydrogenase to proton reduction at a [NiFe] hydrogenase. It is of intense interest due to its ability to efficiently produce H2 during fermentation, its reversibility, allowing H2-dependent CO2 reduction, and its evolutionary link to respiratory complex I. FHL has been studied for over a century, but its atomic structure remains unknown. Here we report cryo-EM structures of FHL in its aerobically and anaerobically isolated forms at resolutions reaching 2.6 Å. This includes well-resolved density for conserved loops linking the soluble and membrane arms believed to be essential in coupling enzymatic turnover to ion translocation across the membrane in the complex I superfamily. We evaluate possible structural determinants of the bias toward hydrogen production over its oxidation and describe an unpredicted metal-binding site near the interface of FdhF and HycF subunits that may play a role in redox-dependent regulation of FdhF interaction with the complex. New cryo-EM structures of the formate hydrogenlyase complex from the model bacterium E. coli clarify how electrons and protons move through the complex and are combined to make H2 gas. The complex shows important similarities and differences to related bioenergetic complexes across the tree of life.
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66
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Kravchuk V, Petrova O, Kampjut D, Wojciechowska-Bason A, Breese Z, Sazanov L. A universal coupling mechanism of respiratory complex I. Nature 2022; 609:808-814. [DOI: 10.1038/s41586-022-05199-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/05/2022] [Indexed: 11/09/2022]
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Vikramdeo KS, Sudan SK, Singh AP, Singh S, Dasgupta S. Mitochondrial respiratory complexes: Significance in human mitochondrial disorders and cancers. J Cell Physiol 2022; 237:4049-4078. [PMID: 36074903 DOI: 10.1002/jcp.30869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/18/2022] [Accepted: 08/23/2022] [Indexed: 11/07/2022]
Abstract
Mitochondria are pivotal organelles that govern cellular energy production through the oxidative phosphorylation system utilizing five respiratory complexes. In addition, mitochondria also contribute to various critical signaling pathways including apoptosis, damage-associated molecular patterns, calcium homeostasis, lipid, and amino acid biosynthesis. Among these diverse functions, the energy generation program oversee by mitochondria represents an immaculate orchestration and functional coordination between the mitochondria and nuclear encoded molecules. Perturbation in this program through respiratory complexes' alteration results in the manifestation of various mitochondrial disorders and malignancy, which is alarmingly becoming evident in the recent literature. Considering the clinical relevance and importance of this emerging medical problem, this review sheds light on the timing and nature of molecular alterations in various respiratory complexes and their functional consequences observed in various mitochondrial disorders and human cancers. Finally, we discussed how this wealth of information could be exploited and tailored to develop respiratory complex targeted personalized therapeutics and biomarkers for better management of various incurable human mitochondrial disorders and cancers.
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Affiliation(s)
- Kunwar Somesh Vikramdeo
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Sarabjeet Kour Sudan
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Ajay P Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Seema Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Santanu Dasgupta
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
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68
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Binding of Natural Inhibitors to Respiratory Complex I. Pharmaceuticals (Basel) 2022; 15:ph15091088. [PMID: 36145309 PMCID: PMC9503403 DOI: 10.3390/ph15091088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) is a redox-driven proton pump with a central role in mitochondrial oxidative phosphorylation. The ubiquinone reduction site of complex I is located in the matrix arm of this large protein complex and connected to the membrane via a tunnel. A variety of chemically diverse compounds are known to inhibit ubiquinone reduction by complex I. Rotenone, piericidin A, and annonaceous acetogenins are representatives of complex I inhibitors from biological sources. The structure of complex I is determined at high resolution, and inhibitor binding sites are described in detail. In this review, we summarize the state of knowledge of how natural inhibitors bind in the Q reduction site and the Q access pathway and how their inhibitory mechanisms compare with that of a synthetic anti-cancer agent.
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Supplementation of Dimethylglycine Sodium Salt in Sow Milk Reverses Skeletal Muscle Redox Status Imbalance and Mitochondrial Dysfunction of Intrauterine Growth Restriction Newborns. Antioxidants (Basel) 2022; 11:antiox11081550. [PMID: 36009269 PMCID: PMC9404796 DOI: 10.3390/antiox11081550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/28/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
The current study sought to understand the mechanism underlying skeletal muscle dysfunction brought on by intrauterine growth restriction (IUGR) and to explore the treatment benefits of applying dimethylglycine sodium salt (DMG-Na) in sow milk to newborns during the suckling period. Each of the 10 sows delivered one newborn with a normal birth weight (NBW) and one with an IUGR. Additionally, two NBW and two IUGR newborns were collected per litter of another 10 sows. The 20 NBW newborns were divided between the N (sow milk) and ND (sow milk + 0.1% DMG-Na) groups, while 20 IUGR newborns were divided between the I (sow milk) and ID (sow milk + 0.1% DMG-Na) groups. The skeletal muscle histomorphology, redox status, and levels of gene and protein expression were worse (p < 0.05) in the I group than in the N group. In addition, supplementation with DMG-Na (ND and ID groups) improved (p < 0.05) those parameters compared to the unsupplemented groups (N and I groups). Inhibited nuclear factor erythroid 2-related factor 2 (Nrf2)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptorγcoactivator-1α (PGC-1α) activity resulted in decreased redox status, skeletal muscle structural damage, skeletal muscle mitochondrial function impairment, and decreased performance in IUGR newborns. Supplementation of DMG-Na in sow milk activated the Nrf2/SIRT1/PGC-1α in IUGR newborns, thereby improving their skeletal muscle performance.
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70
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Meyer EH, Letts JA, Maldonado M. Structural insights into the assembly and the function of the plant oxidative phosphorylation system. THE NEW PHYTOLOGIST 2022; 235:1315-1329. [PMID: 35588181 DOI: 10.1111/nph.18259] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/05/2022] [Indexed: 05/23/2023]
Abstract
One of the key functions of mitochondria is the production of ATP to support cellular metabolism and growth. The last step of mitochondrial ATP synthesis is performed by the oxidative phosphorylation (OXPHOS) system, an ensemble of protein complexes embedded in the inner mitochondrial membrane. In the last 25 yr, many structures of OXPHOS complexes and supercomplexes have been resolved in yeast, mammals, and bacteria. However, structures of plant OXPHOS enzymes only became available very recently. In this review, we highlight the plant-specific features revealed by the recent structures and discuss how they advance our understanding of the function and assembly of plant OXPHOS complexes. We also propose new hypotheses to be tested and discuss older findings to be re-evaluated. Further biochemical and structural work on the plant OXPHOS system will lead to a deeper understanding of plant respiration and its regulation, with significant agricultural, environmental, and societal implications.
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Affiliation(s)
- Etienne H Meyer
- Institute of Plant Physiology, Martin-Luther-University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Maria Maldonado
- Department of Molecular and Cellular Biology, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
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71
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Cryo-EM structures of Na +-pumping NADH-ubiquinone oxidoreductase from Vibrio cholerae. Nat Commun 2022; 13:4082. [PMID: 35882843 PMCID: PMC9325719 DOI: 10.1038/s41467-022-31718-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/29/2022] [Indexed: 11/08/2022] Open
Abstract
The Na+-pumping NADH-ubiquinone oxidoreductase (Na+-NQR) couples electron transfer from NADH to ubiquinone with Na+-pumping, generating an electrochemical Na+ gradient that is essential for energy-consuming reactions in bacteria. Since Na+-NQR is exclusively found in prokaryotes, it is a promising target for highly selective antibiotics. However, the molecular mechanism of inhibition is not well-understood for lack of the atomic structural information about an inhibitor-bound state. Here we present cryo-electron microscopy structures of Na+-NQR from Vibrio cholerae with or without a bound inhibitor at 2.5- to 3.1-Å resolution. The structures reveal the arrangement of all six redox cofactors including a herein identified 2Fe-2S cluster located between the NqrD and NqrE subunits. A large part of the hydrophilic NqrF is barely visible in the density map, suggesting a high degree of flexibility. This flexibility may be responsible to reducing the long distance between the 2Fe-2S centers in NqrF and NqrD/E. Two different types of specific inhibitors bind to the N-terminal region of NqrB, which is disordered in the absence of inhibitors. The present study provides a foundation for understanding the function of Na+-NQR and the binding manner of specific inhibitors.
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72
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Gopalasingam CC, Hasnain SS. Frontiers in metalloprotein crystallography and cryogenic electron microscopy. Curr Opin Struct Biol 2022; 75:102420. [PMID: 35841747 DOI: 10.1016/j.sbi.2022.102420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 11/03/2022]
Abstract
Metalloproteins comprise at least a third of all proteins that utilize redox properties of transition metals on their own or as parts of cofactors. The development of third generation storage ring sources and X-ray free-electron lasers with femtosecond pulses in the first decade of the 21st century has transformed metalloprotein crystallography. In the past decade, cryogenic-electron microscopy single-particle analysis, which does not require crystallization of biological samples has been extensively utilized, particularly for membrane-bound metalloprotein systems. Here, we explore recent frontiers in metalloprotein crystallography and cryogenic electron microscopy, organized for convenience under three metalloprotein-centered biological cycles, focusing on contributions from each technique, their synergy and the ability to preserve metals' redox states when subjected to a particular probe.
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Affiliation(s)
- Chai C Gopalasingam
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK; Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo, 678-1297, Japan. https://twitter.com/@Chai_Gopal
| | - S Samar Hasnain
- Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, UK.
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73
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Schut GJ, Haja DK, Feng X, Poole FL, Li H, Adams MWW. An Abundant and Diverse New Family of Electron Bifurcating Enzymes With a Non-canonical Catalytic Mechanism. Front Microbiol 2022; 13:946711. [PMID: 35875533 PMCID: PMC9304861 DOI: 10.3389/fmicb.2022.946711] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms utilize electron bifurcating enzymes in metabolic pathways to carry out thermodynamically unfavorable reactions. Bifurcating FeFe-hydrogenases (HydABC) reversibly oxidize NADH (E′∼−280 mV, under physiological conditions) and reduce protons to H2 gas (E°′−414 mV) by coupling this endergonic reaction to the exergonic reduction of protons by reduced ferredoxin (Fd) (E′∼−500 mV). We show here that HydABC homologs are surprisingly ubiquitous in the microbial world and are represented by 57 phylogenetically distinct clades but only about half are FeFe-hydrogenases. The others have replaced the hydrogenase domain with another oxidoreductase domain or they contain additional subunits, both of which enable various third reactions to be reversibly coupled to NAD+ and Fd reduction. We hypothesize that all of these enzymes carry out electron bifurcation and that their third substrates can include hydrogen peroxide, pyruvate, carbon monoxide, aldehydes, aryl-CoA thioesters, NADP+, cofactor F420, formate, and quinones, as well as many yet to be discovered. Some of the enzymes are proposed to be integral membrane-bound proton-translocating complexes. These different functionalities are associated with phylogenetically distinct clades and in many cases with specific microbial phyla. We propose that this new and abundant class of electron bifurcating enzyme be referred to as the Bfu family whose defining feature is a conserved bifurcating BfuBC core. This core contains FMN and six iron sulfur clusters and it interacts directly with ferredoxin (Fd) and NAD(H). Electrons to or from the third substrate are fed into the BfuBC core via BfuA. The other three known families of electron bifurcating enzyme (abbreviated as Nfn, EtfAB, and HdrA) contain a special FAD that bifurcates electrons to high and low potential pathways. The Bfu family are proposed to use a different electron bifurcation mechanism that involves a combination of FMN and three adjacent iron sulfur clusters, including a novel [2Fe-2S] cluster with pentacoordinate and partial non-Cys coordination. The absolute conservation of the redox cofactors of BfuBC in all members of the Bfu enzyme family indicate they have the same non-canonical mechanism to bifurcate electrons. A hypothetical catalytic mechanism is proposed as a basis for future spectroscopic analyses of Bfu family members.
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Affiliation(s)
- Gerrit J. Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Dominik K. Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Xiang Feng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Farris L. Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- *Correspondence: Michael W. W. Adams, ; orcid.org/0000-0002-9796-5014
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Respiratory complex I with charge symmetry in the membrane arm pumps protons. Proc Natl Acad Sci U S A 2022; 119:e2123090119. [PMID: 35759670 PMCID: PMC9271201 DOI: 10.1073/pnas.2123090119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Respiratory complex I is a central enzyme of cellular energy metabolism coupling quinone reduction with proton translocation. Its mechanism, especially concerning proton translocation, remains enigmatic. Three homologous subunits that contain a conserved pattern of charged and polar amino acid residues catalyze proton translocation. Strikingly, the central subunit NuoM contains a conserved glutamate residue at a position where conserved lysine residues are found in the other two subunits, resulting in a charge asymmetry discussed to be essential for proton translocation. We found that the respective glutamate to lysine mutation in Escherichia coli complex I lowers the amount of protons translocated per electron transferred by one-quarter. These data clarify the discussion about possible mechanisms of proton translocation by complex I. Energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, is essential for cellular energy metabolism coupling NADH oxidation to proton translocation. The mechanism of proton translocation by complex I is still under debate. Its membrane arm contains an unusual central axis of polar and charged amino acid residues connecting the quinone binding site with the antiporter-type subunits NuoL, NuoM, and NuoN, proposed to catalyze proton translocation. Quinone chemistry probably causes conformational changes and electrostatic interactions that are propagated through these subunits by a conserved pattern of predominantly lysine, histidine, and glutamate residues. These conserved residues are thought to transfer protons along and across the membrane arm. The distinct charge distribution in the membrane arm is a prerequisite for proton translocation. Remarkably, the central subunit NuoM contains a conserved glutamate residue in a position that is taken by a lysine residue in the two other antiporter-type subunits. It was proposed that this charge asymmetry is essential for proton translocation, as it should enable NuoM to operate asynchronously with NuoL and NuoN. Accordingly, we exchanged the conserved glutamate in NuoM for a lysine residue, introducing charge symmetry in the membrane arm. The stably assembled variant pumps protons across the membrane, but with a diminished H+/e− stoichiometry of 1.5. Thus, charge asymmetry is not essential for proton translocation by complex I, casting doubts on the suggestion of an asynchronous operation of NuoL, NuoM, and NuoN. Furthermore, our data emphasize the importance of a balanced charge distribution in the protein for directional proton transfer.
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75
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Brokatzky D, Häcker G. Mitochondria: intracellular sentinels of infections. Med Microbiol Immunol 2022; 211:161-172. [PMID: 35790577 PMCID: PMC9255486 DOI: 10.1007/s00430-022-00742-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/14/2022] [Indexed: 01/19/2023]
Abstract
Structure and integrity of the mitochondrial network play important roles in many cellular processes. Loss of integrity can lead to the activation of a variety of signalling pathways and affect the cell’s response to infections. The activation of such mitochondria-mediated cellular responses has implications for infection recognition, signal transduction and pathogen control. Although we have a basic understanding of mitochondrial factors such as mitochondrial DNA or RNA that may be involved in processes like pro-inflammatory signalling, the diverse roles of mitochondria in host defence remain unclear. Here we will first summarise the functions of mitochondria in the host cell and provide an overview of the major known mitochondrial stress responses. We will then present recent studies that have contributed to the understanding of the role of mitochondria in infectious diseases and highlight a number of recently investigated models of bacterial and viral infections.
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Affiliation(s)
- Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Georg Häcker
- Institute of Medical Microbiology and Hygiene, Medical Centre University of Freiburg, Faculty of Medicine, 79104, Freiburg, Germany
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76
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Caudal A, Ren L, Tu C, Wu JC. Human Induced Pluripotent Stem Cells for Studying Mitochondrial Diseases in the Heart. FEBS Lett 2022; 596:1735-1745. [PMID: 35788991 DOI: 10.1002/1873-3468.14444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/11/2022] [Accepted: 06/28/2022] [Indexed: 11/09/2022]
Abstract
Mitochondrial dysfunction is known to contribute to a range of diseases, and primary mitochondrial defects strongly impact high-energy organs such as the heart. Platforms for high-throughput and human-relevant assessment of mitochondrial diseases are currently lacking, hindering the development of targeted therapies. In the past decade, human induced pluripotent stem cells (iPSCs) have become a promising technology for drug discovery in basic and clinical research. In particular, human iPSC-derived cardiomyocytes (iPSC-CMs) offer a unique tool to study a wide range of mitochondrial functions and possess the potential to become a key translational asset for mitochondrial drug development. This review summarizes mitochondrial functions and recent therapeutic discoveries, advancements, and limitations of using iPSC-CMs to study mitochondrial diseases of the heart with an emphasis on cardiac applications.
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Affiliation(s)
- Arianne Caudal
- Stanford Cardiovascular Institute.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford.,Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Lu Ren
- Stanford Cardiovascular Institute.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford.,Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Chengyi Tu
- Stanford Cardiovascular Institute.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford.,Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Joseph C Wu
- Stanford Cardiovascular Institute.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford.,Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA
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77
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Bai K, Jiang L, Wang T. Dimethylglycine Sodium Salt Alleviates Intrauterine Growth Restriction-Induced Low Growth Performance, Redox Status Imbalance, and Hepatic Mitochondrial Dysfunction in Suckling Piglets. Front Vet Sci 2022; 9:905488. [PMID: 35812869 PMCID: PMC9263627 DOI: 10.3389/fvets.2022.905488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 05/09/2022] [Indexed: 11/29/2022] Open
Abstract
This study aimed to investigate the mechanism of redox status imbalance and hepatic mitochondrial dysfunction induced by intrauterine growth restriction (IUGR) and relieve this condition through dimethylglycine sodium salt (DMG-Na) supplementation during the suckling period. Thirty normal birth weight (NBW) and 30 IUGR newborns were selected from 20 sows. Briefly, 1 NBW and 1 IUGR newborn were obtained from each litter of 10 sows, and 10 NBW and 10 IUGR newborns were obtained. Additionally, 2 NBW and 2 IUGR newborns were obtained from each litter of another 10 sows, and 20 NBW newborns were allocated to the N [basic milk diets (BMDs)] and ND (BMDs+0.1% DMG-Na) groups. Furthermore, 20 IUGR newborns were assigned to the I (BMDs) and ID (BMDs+0.1% DMG-Na) groups. The results revealed that the growth performance, serum and hepatic redox status, and hepatic gene and protein expression levels were lower (P < 0.05) in the I group compared to the N group. Additionally, supplementation with DMG-Na (ND and ID groups) improved (P < 0.05) these parameters compared to the non-supplemented groups (N and I groups). In conclusion, the activity of Nrf2/SIRT1/PGC1α was inhibited in IUGR newborns, and this led to their hepatic dysfunctions. Supplementation with DMG-Na activated Nrf2/SIRT1/PGC1α in IUGR newborns, thereby improving their performance.
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Affiliation(s)
- Kaiwen Bai
- College of Animal Sciences and Technology, Nanjing Agricultural University, Nanjing, China
| | - Luyi Jiang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Tian Wang
- College of Animal Sciences and Technology, Nanjing Agricultural University, Nanjing, China
- *Correspondence: Tian Wang
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78
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Molina-Granada D, González-Vioque E, Dibley MG, Cabrera-Pérez R, Vallbona-Garcia A, Torres-Torronteras J, Sazanov LA, Ryan MT, Cámara Y, Martí R. Most mitochondrial dGTP is tightly bound to respiratory complex I through the NDUFA10 subunit. Commun Biol 2022; 5:620. [PMID: 35739187 PMCID: PMC9226000 DOI: 10.1038/s42003-022-03568-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/08/2022] [Indexed: 12/30/2022] Open
Abstract
Imbalanced mitochondrial dNTP pools are known players in the pathogenesis of multiple human diseases. Here we show that, even under physiological conditions, dGTP is largely overrepresented among other dNTPs in mitochondria of mouse tissues and human cultured cells. In addition, a vast majority of mitochondrial dGTP is tightly bound to NDUFA10, an accessory subunit of complex I of the mitochondrial respiratory chain. NDUFA10 shares a deoxyribonucleoside kinase (dNK) domain with deoxyribonucleoside kinases in the nucleotide salvage pathway, though no specific function beyond stabilizing the complex I holoenzyme has been described for this subunit. We mutated the dNK domain of NDUFA10 in human HEK-293T cells while preserving complex I assembly and activity. The NDUFA10E160A/R161A shows reduced dGTP binding capacity in vitro and leads to a 50% reduction in mitochondrial dGTP content, proving that most dGTP is directly bound to the dNK domain of NDUFA10. This interaction may represent a hitherto unknown mechanism regulating mitochondrial dNTP availability and linking oxidative metabolism to DNA maintenance.
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Affiliation(s)
- David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Emiliano González-Vioque
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
- Department of Clinical Biochemistry, Hospital Universitario Puerta del Hierro-Majadahonda, Madrid, Spain
| | - Marris G Dibley
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Raquel Cabrera-Pérez
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Antoni Vallbona-Garcia
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain.
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
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79
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Kampjut D, Sazanov LA. Structure of respiratory complex I – An emerging blueprint for the mechanism. Curr Opin Struct Biol 2022; 74:102350. [PMID: 35316665 PMCID: PMC7613608 DOI: 10.1016/j.sbi.2022.102350] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/25/2022] [Accepted: 02/08/2022] [Indexed: 11/26/2022]
Abstract
Complex I is one of the major respiratory complexes, conserved from bacteria to mammals. It oxidises NADH, reduces quinone and pumps protons across the membrane, thus playing a central role in the oxidative energy metabolism. In this review we discuss our current state of understanding the structure of complex I from various species of mammals, plants, fungi, and bacteria, as well as of several complex I-related proteins. By comparing the structural evidence from these systems in different redox states and data from mutagenesis and molecular simulations, we formulate the mechanisms of electron transfer and proton pumping and explain how they are conformationally and electrostatically coupled. Finally, we discuss the structural basis of the deactivation phenomenon in mammalian complex I.
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80
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Uno S, Masuya T, Zdorevskyi O, Ikunishi R, Shinzawa-Itoh K, Lasham J, Sharma V, Murai M, Miyoshi H. Diverse reaction behaviors of artificial ubiquinones in mitochondrial respiratory complex I. J Biol Chem 2022; 298:102075. [PMID: 35643318 PMCID: PMC9243180 DOI: 10.1016/j.jbc.2022.102075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022] Open
Abstract
The ubiquinone (UQ) reduction step catalyzed by NADH-UQ oxidoreductase (mitochondrial respiratory complex I) is key to triggering proton translocation across the inner mitochondrial membrane. Structural studies have identified a long, narrow, UQ-accessing tunnel within the enzyme. We previously demonstrated that synthetic oversized UQs, which are unlikely to transit this narrow tunnel, are catalytically reduced by native complex I embedded in submitochondrial particles but not by the isolated enzyme. To explain this contradiction, we hypothesized that access of oversized UQs to the reaction site is obstructed in the isolated enzyme because their access route is altered following detergent solubilization from the inner mitochondrial membrane. In the present study, we investigated this using two pairs of photoreactive UQs (pUQm-1/pUQp-1 and pUQm-2/pUQp-2), with each pair having the same chemical properties except for a ∼1.0 Å difference in side-chain widths. Despite this subtle difference, reduction of the wider pUQs by the isolated complex was significantly slower than of the narrower pUQs, but both were similarly reduced by the native enzyme. In addition, photoaffinity-labeling experiments using the four [125I]pUQs demonstrated that their side chains predominantly label the ND1 subunit with both enzymes but at different regions around the tunnel. Finally, we show that the suppressive effects of different types of inhibitors on the labeling significantly changed depending on [125I]pUQs used, indicating that [125I]pUQs and these inhibitors do not necessarily share a common binding cavity. Altogether, we conclude that the reaction behaviors of pUQs cannot be simply explained by the canonical UQ tunnel model.
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Affiliation(s)
- Shinpei Uno
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | - Ryo Ikunishi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kyoko Shinzawa-Itoh
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Jonathan Lasham
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - 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.
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81
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Wang P, Leontyev I, Stuchebrukhov AA. Mechanical Allosteric Couplings of Redox-Induced Conformational Changes in Respiratory Complex I. J Phys Chem B 2022; 126:4080-4088. [PMID: 35612955 DOI: 10.1021/acs.jpcb.2c00750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We apply linear response theory to calculate mechanical allosteric couplings in respiratory complex I between the iron sulfur cluster N2, located in the catalytic cavity, and the membrane part of the enzyme, separated from it by more than 50 Å. According to our hypothesis, the redox reaction of ubiquinone in the catalytic cavity of the enzyme generates an unbalanced charge that via repulsion of the charged redox center N2 produces local mechanical stress that transmits into the membrane part of the enzyme where it induces proton pumping. Using coarse-grained simulations of the enzyme, we calculated mechanistic allosteric couplings that reveal the pathways of the mechanical transmission of the stress along the enzyme. The results shed light on the recent experimental studies where a stabilization of the enzyme with an introduced disulfide bridge resulted in the abolishing of proton pumping. Simulation of the disulfide bond action indicates a dramatic change of the mechanistic coupling pathways in line with experimental findings.
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Affiliation(s)
- Panyue Wang
- Department of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Igor Leontyev
- Department of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
| | - Alexei A Stuchebrukhov
- Department of Chemistry, University of California at Davis, One Shields Avenue, Davis, California 95616, United States
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82
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Cryo-EM structures define ubiquinone-10 binding to mitochondrial complex I and conformational transitions accompanying Q-site occupancy. Nat Commun 2022; 13:2758. [PMID: 35589726 PMCID: PMC9120487 DOI: 10.1038/s41467-022-30506-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial complex I is a central metabolic enzyme that uses the reducing potential of NADH to reduce ubiquinone-10 (Q10) and drive four protons across the inner mitochondrial membrane, powering oxidative phosphorylation. Although many complex I structures are now available, the mechanisms of Q10 reduction and energy transduction remain controversial. Here, we reconstitute mammalian complex I into phospholipid nanodiscs with exogenous Q10. Using cryo-EM, we reveal a Q10 molecule occupying the full length of the Q-binding site in the 'active' (ready-to-go) resting state together with a matching substrate-free structure, and apply molecular dynamics simulations to propose how the charge states of key residues influence the Q10 binding pose. By comparing ligand-bound and ligand-free forms of the 'deactive' resting state (that require reactivating to catalyse), we begin to define how substrate binding restructures the deactive Q-binding site, providing insights into its physiological and mechanistic relevance.
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83
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Bai K, Jiang L, Wei C, Li Q, Zhang L, Zhang J, Wang T. Dimethylglycine sodium salt activates Nrf2/SIRT1/PGC1α leading to the recovery of muscle stem cell dysfunction in newborns with intrauterine growth restriction. Free Radic Biol Med 2022; 184:89-98. [PMID: 35405266 DOI: 10.1016/j.freeradbiomed.2022.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/29/2022] [Accepted: 04/05/2022] [Indexed: 12/12/2022]
Abstract
The objectives of this study were focused on the mechanism of mitochondrial dysfunction in skeletal muscle stem cells (MuSCs) from intrauterine growth restriction (IUGR) newborn piglets, and the relief of dimethylglycine sodium salt (DMG-Na) on MuSCs mitochondrial dysfunction by Nrf2/SIRT1/PGC1α network. In this study, six newborn piglets with normal birth weight (NBW) and six IUGR newborn piglets were slaughtered immediately after birth to obtain longissimus dorsi muscle (LM) samples. MuSCs were collected and divided into three groups: MuSCs from NBW newborn piglets (N), MuSCs from IUGR newborn piglets (I), and MuSCs from IUGR newborn piglets with 32 μmol DMG-Na (ID). Compared with the NBW group, the IUGR group showed decreased (P < 0.05) serum and LM antioxidant defense capacity, and increased (P < 0.05) serum and LM damage. Compared with the N group, the I group showed decreased (P < 0.05) MuSCs antioxidant defense capacity, mitochondrial ETC complexes, energy metabolites, and antioxidant defense-related and mitochondrial function-related gene and protein expression levels. The antioxidant defense capacity, mitochondrial ETC complexes, energy metabolites, and antioxidant defense-related and mitochondrial function-related gene and protein expression levels of MuSCs were improved (P < 0.05) in the ID group compared to those in the I group. The MuSCs of IUGR newborns activate the Nrf2/SIRT1/PGC1α network by taking in DMG-Na, thereby neutralizing excessive generated O2•- that may help to improve their unfavorable mitochondrial dysfunction in skeletal muscle.
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Affiliation(s)
- Kaiwen Bai
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Luyi Jiang
- College of Animal Science, Zhejiang University, Hangzhou, Zhejiang, 310000, China
| | - Chengheng Wei
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Qiming Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Lili Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Jingfei Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Tian Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
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84
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Jeon TJ, Lee SG, Yoo SH, Kim M, Song D, Ryu J, Park H, Kim DS, Hyun J, Kim HM, Ryu SE. A Dynamic Substrate Pool Revealed by cryo-EM of a Lipid-Preserved Respiratory Supercomplex. Antioxid Redox Signal 2022; 36:1101-1118. [PMID: 34913730 DOI: 10.1089/ars.2021.0114] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Aims: Mitochondrial respiratory supercomplexes mediate redox electron transfer, generating a proton gradient for ATP synthesis. To provide structural information on the function of supercomplexes in physiologically relevant conditions, we conducted cryoelectron microscopy studies with supercomplexes in a lipid-preserving state. Results: Here, we present cryoelectron microscopy structures of bovine respiratory supercomplex I1III2IV1 by using a lipid-preserving sample preparation. The preparation greatly enhances the intercomplex quinone transfer activity. The structures reveal large intercomplex motions that result in different shapes and sizes of the intercomplex space between complexes I and III, forming a dynamic substrate pool. Biochemical and structural analyses indicated that intercomplex phospholipids mediate the intercomplex motions. An analysis of the different classes of focus-refined complex I showed that structural switches due to quinone reduction led to the formation of a novel channel that could transfer reduced quinones to the intercomplex substrate pool. Innovation and Conclusion: Our results indicate potential mechanism for the facilitated electron transfer involving a dynamic substrate pool and intercomplex movement by which supercomplexes play an active role in the regulation of metabolic flux and reactive oxygen species.
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Affiliation(s)
- Tae Jin Jeon
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
- National Instrumentation Center for Environmental Management (NICEM), Seoul National University, Seoul, Korea
| | - Seong-Gyu Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- Center for Biomolecular and Cellular Structure, Institute for Basic Science (IBS), Daejeon, Korea
| | - Suk Hyun Yoo
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Myeongbin Kim
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Dabin Song
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Joonghyun Ryu
- Voronoi Diagram Research Center, Hanyang University, Seoul, Korea
| | - Hwangseo Park
- Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea
| | - Deok-Soo Kim
- Voronoi Diagram Research Center, Hanyang University, Seoul, Korea
- School of Mechanical Engineering, College of Engineering, Hanyang University, Seoul, Korea
| | - Jaekyung Hyun
- Department of Convergence Medicine, Pusan National University Medical School, Gyeongsangnamdo, Korea
- Electron Microscopy Research Center, Korea Basic Science Institute (KBSI), Chungcheongbukdo, Korea
| | - Ho Min Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- Center for Biomolecular and Cellular Structure, Institute for Basic Science (IBS), Daejeon, Korea
| | - Seong Eon Ryu
- Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea
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85
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Burger N, James AM, Mulvey JF, Hoogewijs K, Ding S, Fearnley IM, Loureiro-López M, Norman AAI, Arndt S, Mottahedin A, Sauchanka O, Hartley RC, Krieg T, Murphy MP. ND3 Cys39 in complex I is exposed during mitochondrial respiration. Cell Chem Biol 2022; 29:636-649.e14. [PMID: 34739852 PMCID: PMC9076552 DOI: 10.1016/j.chembiol.2021.10.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/21/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Mammalian complex I can adopt catalytically active (A-) or deactive (D-) states. A defining feature of the reversible transition between these two defined states is thought to be exposure of the ND3 subunit Cys39 residue in the D-state and its occlusion in the A-state. As the catalytic A/D transition is important in health and disease, we set out to quantify it by measuring Cys39 exposure using isotopic labeling and mass spectrometry, in parallel with complex I NADH/CoQ oxidoreductase activity. To our surprise, we found significant Cys39 exposure during NADH/CoQ oxidoreductase activity. Furthermore, this activity was unaffected if Cys39 alkylation occurred during complex I-linked respiration. In contrast, alkylation of catalytically inactive complex I irreversibly blocked the reactivation of NADH/CoQ oxidoreductase activity by NADH. Thus, Cys39 of ND3 is exposed in complex I during mitochondrial respiration, with significant implications for our understanding of the A/D transition and the mechanism of complex I.
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Affiliation(s)
- Nils Burger
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Andrew M James
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - John F Mulvey
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Kurt Hoogewijs
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; The Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; Medical Research Council-Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Shujing Ding
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Ian M Fearnley
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Marta Loureiro-López
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | | | - Sabine Arndt
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Amin Mottahedin
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK; Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Olga Sauchanka
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | | | - Thomas Krieg
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Michael P Murphy
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
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86
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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: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [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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87
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Djurabekova A, Galemou Yoga E, Nyman A, Pirttikoski A, Zickermann V, Haapanen O, Sharma V. Docking and molecular simulations reveal a quinone binding site on the surface of respiratory complex I. FEBS Lett 2022; 596:1133-1146. [PMID: 35363885 DOI: 10.1002/1873-3468.14346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/11/2022] [Accepted: 03/24/2022] [Indexed: 11/07/2022]
Abstract
The first component of the mitochondrial electron transport chain is respiratory complex I. Several high-resolution structures of complex I from different species have been resolved. However, despite these significant achievements, the mechanism of redox-coupled proton pumping remains elusive. Here, we combined atomistic docking, molecular dynamics simulations and site-directed mutagenesis on respiratory complex I from Yarrowia lipolytica to identify a quinone (Q) binding site on its surface near the horizontal amphipathic helices of ND1 and NDUFS7 subunits. The surface-bound Q makes stable interactions with conserved charged and polar residues, including the highly conserved Arg72 from the NDUFS7 subunit. The binding and dynamics of a Q molecule at the surface-binding site raises interesting possibilities about the mechanism of complex I, which are discussed.
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Affiliation(s)
| | - Etienne Galemou Yoga
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt am Main, Germany.,Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Aino Nyman
- Department of Physics, University of Helsinki, Finland
| | | | - Volker Zickermann
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt am Main, Germany.,Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Outi Haapanen
- Department of Physics, University of Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Finland.,HiLIFE Institute of Biotechnology, University of Helsinki, Finland
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88
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Zhou L, Maldonado M, Padavannil A, Guo F, Letts JA. Structures of Tetrahymena's respiratory chain reveal the diversity of eukaryotic core metabolism. Science 2022; 376:831-839. [PMID: 35357889 DOI: 10.1126/science.abn7747] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Respiration is a core biological energy-converting process whose last steps are carried out by a chain of multi-subunit complexes in the inner mitochondrial membrane. To probe the functional and structural diversity of eukaryotic respiration, we examined the respiratory chain of the ciliate Tetrahymena thermophila (Tt). Using cryo-electron microscopy on a mixed sample, we solved structures of a supercomplex between Tt-complex I (CI) and Tt-CIII2 (Tt-SC I+III2) and a structure of Tt-CIV2. Tt-SC I+III2 (~2.3 MDa) is a curved assembly with structural and functional symmetry breaking. Tt-CIV2 is a ~2.7 MDa dimer with over 52 subunits per protomer, including mitochondrial carriers and a TIM83-TIM133-like domain. Our structural and functional study of the T. thermophila respiratory chain reveals divergence in key components of eukaryotic respiration, expanding our understanding of core metabolism.
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Affiliation(s)
- Long Zhou
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - María Maldonado
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Abhilash Padavannil
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Fei Guo
- BIOEM Facility, University of California, Davis, CA 95616, USA
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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89
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Hoeser F, Weiß M, Friedrich T. The clinically relevant triple mutation in the mtND1 gene inactivates Escherichia coli complex I. FEBS Lett 2022; 596:1124-1132. [PMID: 35234296 DOI: 10.1002/1873-3468.14325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 11/07/2022]
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in cellular energy metabolism. Complex I deficiencies are the most common cause of mitochondrial dysfunction. Patients suffering from a variety of neurodegenerative diseases carry numerous mutations in the mitochondrially encoded subunits of the complex. The biochemical consequences of these mutations are largely unknown because these genes are difficult to access experimentally. Here, we use Escherichia coli as a model system to characterize the effect of a 7 bp inversion in mtND1 (m.3902-3908inv7) that results in a triple mutation. The triple mutant grew poorly but contained a normal amount of the stably assembled variant. The variant showed no enzymatic activity, which might contribute to the deleterious effect of the mutation in humans.
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Affiliation(s)
- Franziska Hoeser
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Maximilian Weiß
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
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90
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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] [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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91
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Zhang F, Dang QCL, Vik SB. Human clinical mutations in mitochondrially encoded subunits of Complex I can be successfully modeled in E. coli. Mitochondrion 2022; 64:59-72. [PMID: 35306226 PMCID: PMC9035099 DOI: 10.1016/j.mito.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/21/2022] [Accepted: 03/15/2022] [Indexed: 11/28/2022]
Abstract
Respiratory Complex I is the site of a large fraction of the mutations that appear to cause mitochondrial disease. Seven of its subunits are mitochondrially encoded, and therefore, such mutants are particularly difficult to construct in cell-culture model systems. We have selected 13 human clinical mutations found in ND2, ND3, ND4, ND4L, ND5 and ND6 that are generally found at subunit interfaces, and not in critical residues. These mutations have been modeled in E. coli subunits of Complex I, nuoN, nuoA, nuoM, nuoK, nuoL, and nuoJ, respectively. All mutants were expressed from a plasmid encoding the entire nuo operon, and membrane vesicles were analyzed for deamino-NADH oxidase activity, and proton translocation activity. ND5 mutants were also analyzed using a time-delayed expression system, recently described by this lab. Other mutants were analyzed for the ability to associate in subcomplexes, after expression of subsets of the genes. For most mutants there was a positive correlation between those that were previously determined to be pathogenic, or likely to be pathogenic, and those that we found with compromised Complex I activity or subunit interactions in E. coli. In conclusion, this approach provides another way to explore the deleterious effects of human mitochondrial mutations, and it can contribute to molecular understanding of such mutations.
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Affiliation(s)
- Fang Zhang
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Quynh-Chi L Dang
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Steven B Vik
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA.
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92
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Kühlbrandt W. Forty years in cryoEM of membrane proteins. Microscopy (Oxf) 2022; 71:i30-i50. [PMID: 35275191 PMCID: PMC8855526 DOI: 10.1093/jmicro/dfab041] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 10/05/2021] [Accepted: 11/10/2021] [Indexed: 12/13/2022] Open
Abstract
In a surprisingly short time, electron cryo-microscopy (cryoEM) has developed from a niche technique in structural biology to a mainstream method practiced in a rapidly growing number of laboratories around the world. From its beginnings about 40 years ago, cryoEM has had a major impact on the study of membrane proteins, in particular the energy-converting systems from bacterial, mitochondrial and chloroplast membranes. Early work on two-dimensional crystals attained resolutions ∼3.5 Å, but at present, single-particle cryoEM delivers much more detailed structures without crystals. Electron cryo-tomography of membranes and membrane-associated proteins adds valuable context, usually at lower resolution. The review ends with a brief outlook on future prospects.
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Affiliation(s)
- Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Str. 3, Frankfurt am Main 60438, Germany
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93
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Musiani F, Rigobello L, Iommarini L, Carelli V, Degli Esposti M, Ghelli AM. New Insights on Rotenone Resistance of Complex I Induced by the m.11778G>A/ MT-ND4 Mutation Associated with Leber's Hereditary Optic Neuropathy. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27041341. [PMID: 35209128 PMCID: PMC8876992 DOI: 10.3390/molecules27041341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/04/2022] [Accepted: 02/11/2022] [Indexed: 11/16/2022]
Abstract
The finding that the most common mitochondrial DNA mutation m.11778G>A/MT-ND4 (p.R340H) associated with Leber's hereditary optic neuropathy (LHON) induces rotenone resistance has produced a long-standing debate, because it contrasts structural evidence showing that the ND4 subunit is far away from the quinone-reaction site in complex I, where rotenone acts. However, recent cryo-electron microscopy data revealed that rotenone also binds to the ND4 subunit. We investigated the possible structural modifications induced by the LHON mutation and found that its amino acid replacement would disrupt a possible hydrogen bond between native R340 and Q139 in ND4, thereby destabilizing rotenone binding. Our analysis thus explains rotenone resistance in LHON patients as a biochemical signature of its pathogenic effect on complex I.
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Affiliation(s)
- Francesco Musiani
- Dipartimento di Farmacia e Biotecnologie (FABIT), Università di Bologna, I-40126 Bologna, Italy; (F.M.); (L.R.); (L.I.)
| | - Laura Rigobello
- Dipartimento di Farmacia e Biotecnologie (FABIT), Università di Bologna, I-40126 Bologna, Italy; (F.M.); (L.R.); (L.I.)
| | - Luisa Iommarini
- Dipartimento di Farmacia e Biotecnologie (FABIT), Università di Bologna, I-40126 Bologna, Italy; (F.M.); (L.R.); (L.I.)
| | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), Università di Bologna, I-40100 Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, I-40139 Bologna, Italy
- Correspondence: (V.C.); (A.M.G.)
| | - Mauro Degli Esposti
- Center for Genomic Sciences, Universidad Nacional Autónoma de México (UNAM), Cuernavaca 62210, Mexico;
| | - Anna Maria Ghelli
- Dipartimento di Farmacia e Biotecnologie (FABIT), Università di Bologna, I-40126 Bologna, Italy; (F.M.); (L.R.); (L.I.)
- Correspondence: (V.C.); (A.M.G.)
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94
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Curtabbi A, Enríquez JA. The ins and outs of the flavin mononucleotide cofactor of respiratory complex I. IUBMB Life 2022; 74:629-644. [PMID: 35166025 DOI: 10.1002/iub.2600] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/12/2022]
Abstract
The flavin mononucleotide (FMN) cofactor of respiratory complex I occupies a key position in the electron transport chain. Here, the electrons coming from NADH start the sequence of oxidoreduction reactions, which drives the generation of the proton-motive force necessary for ATP synthesis. The overall architecture and the general catalytic proprieties of the FMN site are mostly well established. However, several aspects regarding the complex I flavin cofactor are still unknown. For example, the flavin binding to the N-module, the NADH-oxidizing portion of complex I, lacks a molecular description. The dissociation of FMN from the enzyme is beginning to emerge as an important regulatory mechanism of complex I activity and ROS production. Finally, how mitochondria import and metabolize FMN is still uncertain. This review summarizes the current knowledge on complex I flavin cofactor and discusses the open questions for future research.
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Affiliation(s)
- Andrea Curtabbi
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain.,Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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95
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Gu J, Liu T, Guo R, Zhang L, Yang M. The coupling mechanism of mammalian mitochondrial complex I. Nat Struct Mol Biol 2022; 29:172-182. [PMID: 35145322 DOI: 10.1038/s41594-022-00722-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/06/2022] [Indexed: 01/03/2023]
Abstract
Mammalian respiratory complex I (CI) is a 45-subunit, redox-driven proton pump that generates an electrochemical gradient across the mitochondrial inner membrane to power ATP synthesis in mitochondria. In the present study, we report cryo-electron microscopy structures of CI from Sus scrofa in six treatment conditions at a resolution of 2.4-3.5 Å, in which CI structures of each condition can be classified into two biochemical classes (active or deactive), with a notably higher proportion of active CI particles. These structures illuminate how hydrophobic ubiquinone-10 (Q10) with its long isoprenoid tail is bound and reduced in a narrow Q chamber comprising four different Q10-binding sites. Structural comparisons of active CI structures from our decylubiquinone-NADH and rotenone-NADH datasets reveal that Q10 reduction at site 1 is not coupled to proton pumping in the membrane arm, which might instead be coupled to Q10 oxidation at site 2. Our data overturn the widely accepted previous proposal about the coupling mechanism of CI.
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Affiliation(s)
- Jinke Gu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China.,Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, China
| | - Tianya Liu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Runyu Guo
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China. .,SUSTech Cryo-EM Facility Center, Southern University of Science & Technology, Shenzhen, China.
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96
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Vercellino I, Sazanov LA. The assembly, regulation and function of the mitochondrial respiratory chain. Nat Rev Mol Cell Biol 2022; 23:141-161. [PMID: 34621061 DOI: 10.1038/s41580-021-00415-0] [Citation(s) in RCA: 263] [Impact Index Per Article: 131.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
The mitochondrial oxidative phosphorylation system is central to cellular metabolism. It comprises five enzymatic complexes and two mobile electron carriers that work in a mitochondrial respiratory chain. By coupling the oxidation of reducing equivalents coming into mitochondria to the generation and subsequent dissipation of a proton gradient across the inner mitochondrial membrane, this electron transport chain drives the production of ATP, which is then used as a primary energy carrier in virtually all cellular processes. Minimal perturbations of the respiratory chain activity are linked to diseases; therefore, it is necessary to understand how these complexes are assembled and regulated and how they function. In this Review, we outline the latest assembly models for each individual complex, and we also highlight the recent discoveries indicating that the formation of larger assemblies, known as respiratory supercomplexes, originates from the association of the intermediates of individual complexes. We then discuss how recent cryo-electron microscopy structures have been key to answering open questions on the function of the electron transport chain in mitochondrial respiration and how supercomplexes and other factors, including metabolites, can regulate the activity of the single complexes. When relevant, we discuss how these mechanisms contribute to physiology and outline their deregulation in human diseases.
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Affiliation(s)
- Irene Vercellino
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
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97
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Padavannil A, Ayala-Hernandez MG, Castellanos-Silva EA, Letts JA. The Mysterious Multitude: Structural Perspective on the Accessory Subunits of Respiratory Complex I. Front Mol Biosci 2022; 8:798353. [PMID: 35047558 PMCID: PMC8762328 DOI: 10.3389/fmolb.2021.798353] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/25/2021] [Indexed: 01/10/2023] Open
Abstract
Complex I (CI) is the largest protein complex in the mitochondrial oxidative phosphorylation electron transport chain of the inner mitochondrial membrane and plays a key role in the transport of electrons from reduced substrates to molecular oxygen. CI is composed of 14 core subunits that are conserved across species and an increasing number of accessory subunits from bacteria to mammals. The fact that adding accessory subunits incurs costs of protein production and import suggests that these subunits play important physiological roles. Accordingly, knockout studies have demonstrated that accessory subunits are essential for CI assembly and function. Furthermore, clinical studies have shown that amino acid substitutions in accessory subunits lead to several debilitating and fatal CI deficiencies. Nevertheless, the specific roles of CI’s accessory subunits have remained mysterious. In this review, we explore the possible roles of each of mammalian CI’s 31 accessory subunits by integrating recent high-resolution CI structures with knockout, assembly, and clinical studies. Thus, we develop a framework of experimentally testable hypotheses for the function of the accessory subunits. We believe that this framework will provide inroads towards the complete understanding of mitochondrial CI physiology and help to develop strategies for the treatment of CI deficiencies.
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Affiliation(s)
- Abhilash Padavannil
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - Maria G Ayala-Hernandez
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - Eimy A Castellanos-Silva
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
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98
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Kaila VRI. Resolving Chemical Dynamics in Biological Energy Conversion: Long-Range Proton-Coupled Electron Transfer in Respiratory Complex I. Acc Chem Res 2021; 54:4462-4473. [PMID: 34894649 PMCID: PMC8697550 DOI: 10.1021/acs.accounts.1c00524] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
![]()
Biological energy conversion is catalyzed by membrane-bound proteins
that transduce chemical or light energy into energy forms that power
endergonic processes in the cell. At a molecular level, these catalytic
processes involve elementary electron-, proton-, charge-, and energy-transfer
reactions that take place in the intricate molecular machineries of
cell respiration and photosynthesis. Recent developments in structural
biology, particularly cryo-electron microscopy (cryoEM), have resolved
the molecular architecture of several energy transducing proteins,
but detailed mechanistic principles of their charge transfer reactions
still remain poorly understood and a major challenge for modern biochemical
research. To this end, multiscale molecular simulations provide a
powerful approach to probe mechanistic principles on a broad range
of time scales (femtoseconds to milliseconds) and spatial resolutions
(101–106 atoms), although technical challenges
also require balancing between the computational accuracy, cost, and
approximations introduced within the model. Here we discuss how the
combination of atomistic (aMD) and hybrid quantum/classical molecular
dynamics (QM/MM MD) simulations with free energy (FE) sampling methods
can be used to probe mechanistic principles of enzymes responsible
for biological energy conversion. We present mechanistic explorations
of long-range proton-coupled electron transfer (PCET) dynamics in
the highly intricate respiratory chain enzyme Complex I, which functions
as a redox-driven proton pump in bacterial and mitochondrial respiratory
chains by catalyzing a 300 Å fully reversible PCET process. This
process is initiated by a hydride (H–) transfer
between NADH and FMN, followed by long-range (>100 Å) electron
transfer along a wire of 8 FeS centers leading to a quinone biding
site. The reduction of the quinone to quinol initiates dissociation
of the latter to a second membrane-bound binding site, and triggers
proton pumping across the membrane domain of complex I, in subunits
up to 200 Å away from the active site. Our simulations across
different size and time scales suggest that transient charge transfer
reactions lead to changes in the internal hydration state of key regions,
local electric fields, and the conformation of conserved ion pairs,
which in turn modulate the dynamics of functional steps along the
reaction cycle. Similar functional principles, which operate on much
shorter length scales, are also found in some unrelated proteins,
suggesting that enzymes may employ conserved principles in the catalysis
of biological energy transduction processes.
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Affiliation(s)
- Ville R. I. Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
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99
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Mühlbauer ME, Gamiz-Hernandez AP, Kaila VRI. Functional Dynamics of an Ancient Membrane-Bound Hydrogenase. J Am Chem Soc 2021; 143:20873-20883. [PMID: 34846879 PMCID: PMC8679088 DOI: 10.1021/jacs.1c09356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The membrane-bound
hydrogenase (Mbh) is a redox-driven Na+/H+ transporter
that employs the energy from hydrogen
gas (H2) production to catalyze proton pumping and Na+/H+ exchange across cytoplasmic membranes of archaea.
Despite a recently resolved structure of this ancient energy-transducing
enzyme [Yu et al. Cell2018, 173, 1636–1649], the molecular principles of its
redox-driven ion-transport mechanism remain puzzling and of major
interest for understanding bioenergetic principles of early cells.
Here we use atomistic molecular dynamics (MD) simulations in combination
with data clustering methods and quantum chemical calculations to
probe principles underlying proton reduction as well as proton and
sodium transport in Mbh from the hyperthermophilic archaeon Pyrococcus furiosus. We identify putative Na+ binding sites and proton pathways leading across the membrane
and to the NiFe-active center as well as conformational changes that
regulate ion uptake. We suggest that Na+ binding and protonation
changes at a putative ion-binding site couple to proton transfer across
the antiporter-like MbhH subunit by modulating the conformational
state of a conserved ion pair at the subunit interface. Our findings
illustrate conserved coupling principles within the complex I superfamily
and provide functional insight into archaeal energy transduction mechanisms.
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Affiliation(s)
- Max E Mühlbauer
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.,Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.,Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
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100
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Quinone binding in respiratory complex I: Going through the eye of a needle. The squeeze-in mechanism of passing the narrow entrance of the quinone site. Photochem Photobiol Sci 2021; 21:1-12. [PMID: 34813075 PMCID: PMC8799541 DOI: 10.1007/s43630-021-00113-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/04/2021] [Indexed: 02/02/2023]
Abstract
At the joint between the membrane and hydrophilic arms of the enzyme, the structure of the respiratory complex I reveals a tunnel-like Q-chamber for ubiquinone binding and reduction. The narrow entrance of the quinone chamber located in ND1 subunit forms a bottleneck (eye of a needle) which in all resolved structures was shown to be too small for a bulky quinone to pass through, and it was suggested that a conformational change is required to open the channel. The closed bottleneck appears to be a well-established feature of all structures reported so-far, both for the so-called open and closed states of the enzyme, with no indication of a stable open state of the bottleneck. We propose a squeeze-in mechanism of the bottleneck passage, where dynamic thermal conformational fluctuations allow quinone to get in and out. Here, using molecular dynamics simulations of the bacterial enzyme, we have identified collective conformational changes that open the quinone chamber bottleneck. The model predicts a significant reduction—due to a need for a rare opening of the bottleneck—of the effective bi-molecular rate constant, in line with the available kinetic data. We discuss possible reasons for such a tight control of the quinone passage into the binding chamber and mechanistic consequences for the quinone two-electron reduction.
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