1
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Alhourani A, Førde JL, Nasrollahzadeh M, Eichacker LA, Herfindal L, Hagland HR. Graphene-based phenformin carriers for cancer cell treatment: a comparative study between oxidized and pegylated pristine graphene in human cells and zebrafish. NANOSCALE ADVANCES 2022; 4:1668-1680. [PMID: 36134366 PMCID: PMC9417205 DOI: 10.1039/d1na00778e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/27/2022] [Indexed: 06/16/2023]
Abstract
Graphene is an attractive choice for the development of an effective drug carrier in cancer treatment due to its high adsorption area and pH-responsive drug affinity. In combination with the highly potent metabolic drug phenformin, increased doses could be efficiently delivered to cancer cells. This study compares the use of graphene oxide (GO) and polyethylene glycol stabilized (PEGylated) pristine graphene nanosheets (PGNSs) for drug delivery applications with phenformin. The cytotoxicity and mitotoxicity of the graphene-based systems were assessed in human cells and zebrafish larvae. Targeted drug release from GO and PGNSs was evaluated at different pH levels known to arise in proliferating tumor microenvironments. PGNSs were less cytotoxic and mitotoxic than GO, and showed an increased release of phenformin at lower pH in cells, compared to GO. In addition, the systemic phenformin effect was mitigated in zebrafish larvae when bound to GO and PGNSs compared to free phenformin, as measured by flavin metabolic lifetime imaging. These results pave the way for improved phenformin-based cancer therapy using graphene nano-sheets, where PGNSs were superior to GO.
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Affiliation(s)
- Abdelnour Alhourani
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Jan-Lukas Førde
- Centre for Pharmacy, Department of Clinical Science, University of Bergen Bergen Norway
- Department of Internal Medicine, Haukeland University Hospital Bergen Norway
| | - Mojdeh Nasrollahzadeh
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Lutz Andreas Eichacker
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
| | - Lars Herfindal
- Centre for Pharmacy, Department of Clinical Science, University of Bergen Bergen Norway
| | - Hanne Røland Hagland
- Department of Chemistry, Biosciences and Environmental Engineering, University of Stavanger Stavanger Norway
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2
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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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3
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Yoval-Sánchez B, Ansari F, James J, Niatsetskaya Z, Sosunov S, Filipenko P, Tikhonova IG, Ten V, Wittig I, Rafikov R, Galkin A. Redox-dependent loss of flavin by mitochondria complex I is different in brain and heart. Redox Biol 2022; 51:102258. [PMID: 35189550 PMCID: PMC8861397 DOI: 10.1016/j.redox.2022.102258] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/26/2022] [Accepted: 01/31/2022] [Indexed: 12/14/2022] Open
Abstract
Pathologies associated with tissue ischemia/reperfusion (I/R) in highly metabolizing organs such as the brain and heart are leading causes of death and disability in humans. Molecular mechanisms underlying mitochondrial dysfunction during acute injury in I/R are tissue-specific, but their details are not completely understood. A metabolic shift and accumulation of substrates of reverse electron transfer (RET) such as succinate are observed in tissue ischemia, making mitochondrial complex I of the respiratory chain (NADH:ubiquinone oxidoreductase) the most vulnerable enzyme to the following reperfusion. It has been shown that brain complex I is predisposed to losing its flavin mononucleotide (FMN) cofactor when maintained in the reduced state in conditions of RET both in vitro and in vivo. Here we investigated the process of redox-dependent dissociation of FMN from mitochondrial complex I in brain and heart mitochondria. In contrast to the brain enzyme, cardiac complex I does not lose FMN when reduced in RET conditions. We proposed that the different kinetics of FMN loss during RET is due to the presence of brain-specific long 50 kDa isoform of the NDUFV3 subunit of complex I, which is absent in the heart where only the canonical 10 kDa short isoform is found. Our simulation studies suggest that the long NDUFV3 isoform can reach toward the FMN binding pocket and affect the nucleotide affinity to the apoenzyme. For the first time, we demonstrated a potential functional role of tissue-specific isoforms of complex I, providing the distinct molecular mechanism of I/R-induced mitochondrial impairment in cardiac and cerebral tissues. By combining functional studies of intact complex I and molecular structure simulations, we defined the critical difference between the brain and heart enzyme and suggested insights into the redox-dependent inactivation mechanisms of complex I during I/R injury in both tissues.
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Affiliation(s)
- Belem Yoval-Sánchez
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA
| | - Fariha Ansari
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA
| | - Joel James
- Division of Endocrinology, Department of Medicine, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Zoya Niatsetskaya
- Department of Pediatrics, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, 08901, USA
| | - Sergey Sosunov
- Department of Pediatrics, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, 08901, USA
| | - Peter Filipenko
- Department of Biochemistry, Weill Cornell Medical College, Cornell University, New York, NY, 10021, USA
| | - Irina G. Tikhonova
- School of Pharmacy, Medical Biology, Centre, Queen's University Belfast, Belfast, BT9 7BL, United Kingdom
| | - Vadim Ten
- Department of Pediatrics, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, 08901, USA
| | - Ilka Wittig
- Functional Proteomics, Cardiovascular Physiology, Goethe University, 60590, Frankfurt am Main, Germany,German Center for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Ruslan Rafikov
- Division of Endocrinology, Department of Medicine, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Alexander Galkin
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 East 61st Street, New York, NY, 10065, USA,Corresponding author.
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4
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Jarman OD, Biner O, Wright JJ, Hirst J. Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I. Sci Rep 2021; 11:10143. [PMID: 33980947 PMCID: PMC8115037 DOI: 10.1038/s41598-021-89575-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/27/2021] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.
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Affiliation(s)
- Owen D. Jarman
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Olivier Biner
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - John J. Wright
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Judy Hirst
- grid.5335.00000000121885934The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
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5
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Banerjee S, Sadler PJ. Transfer hydrogenation catalysis in cells. RSC Chem Biol 2021; 2:12-29. [PMID: 34458774 PMCID: PMC8341873 DOI: 10.1039/d0cb00150c] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/10/2020] [Indexed: 12/13/2022] Open
Abstract
Hydrogenation reactions in biology are usually carried out by enzymes with nicotinamide adenine dinucleotide (NAD(P)H) or flavin mononucleotide (FAMH2)/flavinadenine dinucleotide (FADH2) as cofactors and hydride sources. Industrial scale chemical transfer hydrogenation uses small molecules such as formic acid or alcohols (e.g. propanol) as hydride sources and transition metal complexes as catalysts. We focus here on organometallic half-sandwich RuII and OsII η6-arene complexes and RhIII and IrIII η5-Cp x complexes which catalyse hydrogenation of biomolecules such as pyruvate and quinones in aqueous media, and generate biologically important species such as H2 and H2O2. Organometallic catalysts can achieve enantioselectivity, and moreover can be active in living cells, which is surprising on account of the variety of poisons present. Such catalysts can induce reductive stress using formate as hydride source or oxidative stress by accepting hydride from NAD(P)H. In some cases, photocatalytic redox reactions can be induced by light absorption at metal or flavin centres. These artificial transformations can interfere in biochemical pathways in unusual ways, and are the basis for the design of metallodrugs with novel mechanisms of action.
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Affiliation(s)
- Samya Banerjee
- Department of Chemistry, University of Warwick, Gibbet Hill Road Coventry CV4 7AL UK
| | - Peter J Sadler
- Department of Chemistry, University of Warwick, Gibbet Hill Road Coventry CV4 7AL UK
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6
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Melin F, Hellwig P. Redox Properties of the Membrane Proteins from the Respiratory Chain. Chem Rev 2020; 120:10244-10297. [DOI: 10.1021/acs.chemrev.0c00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Frederic Melin
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
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7
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Saura P, Kaila VRI. Energetics and Dynamics of Proton-Coupled Electron Transfer in the NADH/FMN Site of Respiratory Complex I. J Am Chem Soc 2019; 141:5710-5719. [PMID: 30873834 PMCID: PMC6890364 DOI: 10.1021/jacs.8b11059] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Complex I functions as an initial electron acceptor in aerobic respiratory chains that reduces quinone and pumps protons across a biological membrane. This remarkable charge transfer process extends ca. 300 Å and it is initiated by a poorly understood proton-coupled electron transfer (PCET) reaction between nicotinamide adenine dinucleotide (NADH) and a protein-bound flavin (FMN) cofactor. We combine here large-scale density functional theory calculations and quantum/classical models with atomistic molecular dynamics simulations to probe the energetics and dynamics of the NADH-driven PCET reaction in complex I. We find that the reaction takes place by concerted hydrogen atom (H•) transfer that couples to an electron transfer (eT) between the aromatic ring systems of the cofactors and further triggers reduction of the nearby FeS centers. In bacterial, Escherichia coli-like complex I isoforms, reduction of the N1a FeS center increases the binding affinity of the oxidized NAD+ that prevents the nucleotide from leaving prematurely. This electrostatic trapping could provide a protective gating mechanism against reactive oxygen species formation. We also find that proton transfer from the transient FMNH• to a nearby conserved glutamate (Glu97) residue favors eT from N1a onward along the FeS chain and modulates the binding of a new NADH molecule. The PCET in complex I isoforms with low-potential N1a centers is also discussed. On the basis of our combined results, we propose a putative mechanistic model for the NADH-driven proton/electron-transfer reaction in complex I.
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Affiliation(s)
- Patricia Saura
- Department of Chemistry , Technical University of Munich (TUM) , Lichtenbergstrasse 4 , Garching D-85747 , Germany
| | - Ville R I Kaila
- Department of Chemistry , Technical University of Munich (TUM) , Lichtenbergstrasse 4 , Garching D-85747 , Germany
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8
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Stepanova A, Konrad C, Manfredi G, Springett R, Ten V, Galkin A. The dependence of brain mitochondria reactive oxygen species production on oxygen level is linear, except when inhibited by antimycin A. J Neurochem 2019; 148:731-745. [PMID: 30582748 DOI: 10.1111/jnc.14654] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 01/22/2023]
Abstract
Reactive oxygen species (ROS) are by-products of physiological mitochondrial metabolism that are involved in several cellular signaling pathways as well as tissue injury and pathophysiological processes, including brain ischemia/reperfusion injury. The mitochondrial respiratory chain is considered a major source of ROS; however, there is little agreement on how ROS release depends on oxygen concentration. The rate of H2 O2 release by intact brain mitochondria was measured with an Amplex UltraRed assay using a high-resolution respirometer (Oroboros) equipped with a fluorescent optical module and a system of controlled gas flow for varying the oxygen concentration. Three types of substrates were used: malate and pyruvate, succinate and glutamate, succinate alone or glycerol 3-phosphate. For the first time we determined that, with any substrate used in the absence of inhibitors, H2 O2 release by respiring brain mitochondria is linearly dependent on the oxygen concentration. We found that the highest rate of H2 O2 release occurs in conditions of reverse electron transfer when mitochondria oxidize succinate or glycerol 3-phosphate. H2 O2 production by complex III is significant only in the presence of antimycin A and, in this case, the oxygen dependence manifested mixed (linear and hyperbolic) kinetics. We also demonstrated that complex II in brain mitochondria could contribute to ROS generation even in the absence of its substrate succinate when the quinone pool is reduced by glycerol 3-phosphate. Our results underscore the critical importance of reverse electron transfer in the brain, where a significant amount of succinate can be accumulated during ischemia providing a backflow of electrons to complex I at the early stages of reperfusion. Our study also demonstrates that ROS generation in brain mitochondria is lower under hypoxic conditions than in normoxia. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Anna Stepanova
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, Belfast, UK.,Department of Pediatrics, Columbia University, New York, NY, USA
| | - Csaba Konrad
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Roger Springett
- Cardiovascular Division, King's College London, British Heart Foundation Centre of Excellence London, London, UK
| | - Vadim Ten
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Alexander Galkin
- Queen's University Belfast, School of Biological Sciences, Medical Biology Centre, Belfast, UK.,Department of Pediatrics, Columbia University, New York, NY, USA
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9
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Direct electron transfer-type bioelectrocatalytic interconversion of carbon dioxide/formate and NAD+/NADH redox couples with tungsten-containing formate dehydrogenase. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.01.112] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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10
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Shipovskov S, Bonamore A, Boffi A, Ferapontova EE. Electrocatalytic interconversion of NADH and NAD(+) by Escherichia coli flavohemoglobin. Chem Commun (Camb) 2016; 51:16096-8. [PMID: 26389555 DOI: 10.1039/c5cc06317e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
E. coli flavohemoglobin, oriented at electrodes via amphiphilic polymyxin B, electrocatalytically interconverts NADH and NAD(+) at its heme potentials operating as an electron transfer relay between the electrode and the protein FAD, where NADH/NAD(+) is transformed. The results are crucial for the development of NAD(+)-dependent bioelectrodes for biosynthesis, biosensors and biofuel cells.
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Affiliation(s)
- S Shipovskov
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
| | - A Bonamore
- Department of Biochemical Sciences and CNR Institute of Molecular Biology and Pathology, University "La Sapienza", 00185 Rome, Italy
| | - A Boffi
- Department of Biochemical Sciences and CNR Institute of Molecular Biology and Pathology, University "La Sapienza", 00185 Rome, Italy
| | - E E Ferapontova
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
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11
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Gutiérrez-Sanz O, Olea D, Pita M, Batista AP, Alonso A, Pereira MM, Vélez M, De Lacey AL. Reconstitution of respiratory complex I on a biomimetic membrane supported on gold electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9007-9015. [PMID: 24988043 DOI: 10.1021/la501825r] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
For the first time, respiratory complex I has been reconstituted on an electrode preserving its structure and activity. Respiratory complex I is a membrane-bound enzyme that has an essential function in cellular energy production. It couples NADH:quinone oxidoreduction to translocation of ions across the cellular (in prokaryotes) or mitochondrial membranes. Therefore, complex I contributes to the establishment and maintenance of the transmembrane difference of electrochemical potential required for adenosine triphosphate synthesis, transport, and motility. Our new strategy has been applied for reconstituting the bacterial complex I from Rhodothermus marinus onto a biomimetic membrane supported on gold electrodes modified with a thiol self-assembled monolayer (SAM). Atomic force microscopy and faradaic impedance measurements give evidence of the biomimetic construction, whereas electrochemical measurements show its functionality. Both electron transfer and proton translocation by respiratory complex I were monitored, simulating in vivo conditions.
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Affiliation(s)
- Oscar Gutiérrez-Sanz
- Instituto de Catalisis y Petroleoquímica, CSIC, c/Marie Curie 2, L10, 28049 Madrid, Spain
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12
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Emre FB, Lopes P, Ferapontova EE. Implications of FAD Electrode Reaction Kinetics for Electrocatalysis of NADH Oxidation and Development of NAD-Dependent Enzyme Electrodes. ELECTROANAL 2014. [DOI: 10.1002/elan.201400048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Investigating the function of [2Fe-2S] cluster N1a, the off-pathway cluster in complex I, by manipulating its reduction potential. Biochem J 2013; 456:139-46. [PMID: 23980528 PMCID: PMC3898324 DOI: 10.1042/bj20130606] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
NADH:quinone oxidoreductase (complex I) couples NADH oxidation and quinone reduction to proton translocation across an energy-transducing membrane. All complexes I contain a flavin to oxidize NADH, seven iron–sulfur clusters to transfer electrons from the flavin to quinone and an eighth cluster (N1a) on the opposite side of the flavin. The role of cluster N1a is unknown, but Escherichia coli complex I has an unusually high-potential cluster N1a and its reduced flavin produces H2O2, not superoxide, suggesting that cluster N1a may affect reactive oxygen species production. In the present study, we combine protein film voltammetry with mutagenesis in overproduced N1a-binding subunits to identify two residues that switch N1a between its high- (E. coli, valine and asparagine) and low- (Bos taurus and Yarrowia lipolytica, proline and methionine) potential forms. The mutations were incorporated into E. coli complex I: cluster N1a could no longer be reduced by NADH, but H2O2 and superoxide production were unaffected. The reverse mutations (that increase the potential by ~0.16 V) were incorporated into Y. lipolytica complex I, but N1a was still not reduced by NADH. We conclude that cluster N1a does not affect reactive oxygen species production by the complex I flavin; it is probably required for enzyme assembly or stability. Two residues that determine the potential of cluster N1a in respiratory complex I were identified, and their effects on its flavin-site reactions were determined. Reduction of cluster N1a by NADH does not affect reactive oxygen species production by the flavin.
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14
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Lauterbach L, Lenz O. Catalytic production of hydrogen peroxide and water by oxygen-tolerant [NiFe]-hydrogenase during H2 cycling in the presence of O2. J Am Chem Soc 2013; 135:17897-905. [PMID: 24180286 DOI: 10.1021/ja408420d] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hydrogenases control the H2-related metabolism in many microbes. Most of these enzymes are prone to immediate inactivation by O2. However, a few members of the subclass of [NiFe]-hydrogenases are able to convert H2 into protons and electrons even in the presence of O2, making them attractive for biotechnological application. Recent studies on O2-tolerant membrane-bound hydrogenases indicate that the mechanism of O2 tolerance relies on their capability to completely reduce O2 with four electrons to harmless water. In order to verify this hypothesis, we probed the O2 reduction capacity of the soluble, NAD(+)-reducing [NiFe]-hydrogenase (SH) from Ralstonia eutropha H16. A newly established, homologous overexpression allowed the purification of up to 90 mg of homogeneous and highly active enzyme from 10 g of cell material. We showed that the SH produces trace amounts of superoxide in the course of H2-driven NAD(+) reduction in the presence of O2. However, the major products of the SH-mediated oxidase activity was in fact hydrogen peroxide and water as shown by the mass spectrometric detection of H2(18)O formed from H2 and isotopically labeled (18)O2. Water release was also observed when the enzyme was incubated with NADH and (18)O2, demonstrating the importance of reverse electron flow to the [NiFe] active site for O2 reduction. A comparison of the turnover rates for H2 and O2 revealed that in the presence of twice the ambient level of O2, up to 3% of the electrons generated through H2 oxidation serve as "health insurance" and are reused for O2 reduction.
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Affiliation(s)
- Lars Lauterbach
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin , Chausseestrasse 117, 10115 Berlin, Germany
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15
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Abstract
Complex I (NADH:ubiquinone oxidoreductase) is crucial for respiration in many aerobic organisms. In mitochondria, it oxidizes NADH from the tricarboxylic acid cycle and β-oxidation, reduces ubiquinone, and transports protons across the inner membrane, contributing to the proton-motive force. It is also a major contributor to cellular production of reactive oxygen species. The redox reaction of complex I is catalyzed in the hydrophilic domain; it comprises NADH oxidation by a flavin mononucleotide, intramolecular electron transfer along a chain of iron-sulfur clusters, and ubiquinone reduction. Redox-coupled proton translocation in the membrane domain requires long-range energy transfer through the protein complex, and the molecular mechanisms that couple the redox and proton-transfer half-reactions are currently unknown. This review evaluates extant data on the mechanisms of energy transduction and superoxide production by complex I, discusses contemporary mechanistic models, and explores how mechanistic studies may contribute to understanding the roles of complex I dysfunctions in human diseases.
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Affiliation(s)
- Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom.
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16
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Sosna M, Bonamore A, Gorton L, Boffi A, Ferapontova EE. Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphite electrodes. Biosens Bioelectron 2012. [PMID: 23208089 DOI: 10.1016/j.bios.2012.10.094] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Escherichia coli flavohemoglobin (HMP), which contains one heme and one FAD as prosthetic groups and is capable of reducing O₂ by its heme at the expense of NADH oxidized at its FAD site, was electrochemically studied at graphite (Gr) electrodes. Two signals were observed in voltammograms of HMP adsorbed on Gr, at -477 and -171 mV vs. Ag|AgCl, at pH 7.4, correlating with electrochemical responses from the FAD and heme domains, respectively. The electron transfer rate constant for ET reaction between FAD of HMP and the electrode was estimated to be 83 s⁻¹. Direct bioelectrocatalytic oxidation of NADH by HMP was not observed, presumably due to impeded substrate access to HMP orientated on Gr through the FAD-domain and/or partial denaturation of HMP. Bioelectrocatalysis was achieved when HMP was wired to Gr by the Os redox polymers, with the onset of NADH oxidation at the formal potential of the particular Os complex (+140 mV or -195 mV). Apparent Michaelis constants K(M)(app) and j(max) were determined, showing bioelectrocatalytic efficiency of NADH oxidation by HMP exceeding the one earlier shown with diaphorase, which makes HMP very attractive as a component of bioanalytical and bioenergetic devices.
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Affiliation(s)
- Maciej Sosna
- Interdisciplinary Nanoscience Center-iNANO, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
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Bridges HR, Bill E, Hirst J. Mössbauer spectroscopy on respiratory complex I: the iron-sulfur cluster ensemble in the NADH-reduced enzyme is partially oxidized. Biochemistry 2011; 51:149-58. [PMID: 22122402 PMCID: PMC3254188 DOI: 10.1021/bi201644x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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In mitochondria, complex I (NADH:quinone oxidoreductase)
couples
electron transfer to proton translocation across an energy-transducing
membrane. It contains a flavin mononucleotide to oxidize NADH, and
an unusually long series of iron–sulfur (FeS) clusters that
transfer the electrons to quinone. Understanding electron transfer
in complex I requires spectroscopic and structural data to be combined
to reveal the properties of individual clusters and of the ensemble.
EPR studies on complex I from Bos taurus have established
that five clusters (positions 1, 2, 3, 5, and 7 along the seven-cluster
chain extending from the flavin) are (at least partially) reduced
by NADH. The other three clusters, positions 4 and 6 plus a cluster
on the other side of the flavin, are not observed in EPR spectra from
the NADH-reduced enzyme: they may remain oxidized, have unusual or
coupled spin states, or their EPR signals may be too fast relaxing.
Here, we use Mössbauer spectroscopy on 57Fe-labeled
complex I from the mitochondria of Yarrowia lipolytica to show that the cluster ensemble is only partially reduced in the
NADH-reduced enzyme. The three EPR-silent clusters are oxidized, and
only the terminal 4Fe cluster (position 7) is fully reduced. Together
with the EPR analyses, our results reveal an alternating profile of
higher and lower potential clusters between the two active sites in
complex I; they are not consistent with the consensus picture of a
set of isopotential clusters. The implications for intramolecular
electron transfer along the extended chain of cofactors in complex
I are discussed.
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Affiliation(s)
- Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
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18
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Healy AJ, Reeve HA, Parkin A, Vincent KA. Electrically conducting particle networks in polymer electrolyte as three-dimensional electrodes for hydrogenase electrocatalysis. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.01.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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19
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Lauterbach L, Idris Z, Vincent KA, Lenz O. Catalytic properties of the isolated diaphorase fragment of the NAD-reducing [NiFe]-hydrogenase from Ralstonia eutropha. PLoS One 2011; 6:e25939. [PMID: 22016788 PMCID: PMC3189943 DOI: 10.1371/journal.pone.0025939] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 09/14/2011] [Indexed: 11/19/2022] Open
Abstract
The NAD+-reducing soluble hydrogenase (SH) from Ralstonia eutropha H16 catalyzes the H2-driven reduction of NAD+, as well as reverse electron transfer from NADH to H+, in the presence of O2. It comprises six subunits, HoxHYFUI2, and incorporates a [NiFe] H+/H2 cycling catalytic centre, two non-covalently bound flavin mononucleotide (FMN) groups and an iron-sulfur cluster relay for electron transfer. This study provides the first characterization of the diaphorase sub-complex made up of HoxF and HoxU. Sequence comparisons with the closely related peripheral subunits of Complex I in combination with UV/Vis spectroscopy and the quantification of the metal and FMN content revealed that HoxFU accommodates a [2Fe2S] cluster, FMN and a series of [4Fe4S] clusters. Protein film electrochemistry (PFE) experiments show clear electrocatalytic activity for both NAD+ reduction and NADH oxidation with minimal overpotential relative to the potential of the NAD+/NADH couple. Michaelis-Menten constants of 56 µM and 197 µM were determined for NADH and NAD+, respectively. Catalysis in both directions is product inhibited with KI values of around 0.2 mM. In PFE experiments, the electrocatalytic current was unaffected by O2, however in aerobic solution assays, a moderate superoxide production rate of 54 nmol per mg of protein was observed, meaning that the formation of reactive oxygen species (ROS) observed for the native SH can be attributed mainly to HoxFU. The results are discussed in terms of their implications for aerobic functioning of the SH and possible control mechanism for the direction of catalysis.
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Affiliation(s)
- Lars Lauterbach
- Institute of Biology, Department of Microbiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Zulkifli Idris
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, United Kingdom
| | - Kylie A. Vincent
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, United Kingdom
- * E-mail: (KAV); (OL)
| | - Oliver Lenz
- Institute of Biology, Department of Microbiology, Humboldt-Universität zu Berlin, Berlin, Germany
- * E-mail: (KAV); (OL)
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20
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Reeve HA, Lauterbach L, Ash PA, Lenz O, Vincent KA. A modular system for regeneration of NAD cofactors using graphite particles modified with hydrogenase and diaphorase moieties. Chem Commun (Camb) 2011; 48:1589-91. [PMID: 21986817 DOI: 10.1039/c1cc14826e] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyrolytic graphite particles modified with hydrogenase and an NAD(+)/NADH cycling enzyme provide a modular heterogeneous catalyst system for regeneration of oxidised or reduced nicotinamide cofactors using H(2) and H(+) as electron source or sink. Particles can be tuned for cofactor supply under different conditions by appropriate choice of hydrogenase.
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Affiliation(s)
- Holly A Reeve
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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21
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Kang PT, Yun J, Kaumaya PPT, Chen YR. Design and use of peptide-based antibodies decreasing superoxide production by mitochondrial complex I and complex II. Biopolymers 2011; 96:207-21. [PMID: 20564035 DOI: 10.1002/bip.21457] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mitochondria are the major source of reactive oxygen species. Both complex I and complex II mediate O2*- production in mitochondria and host reactive protein thiols. To explore the functions of the specific domains involved in the redox modifications of complexes I and II, various peptide-based antibodies were generated against these complexes, and their inhibitory effects were subsequently measured. The redox domains involved in S-glutathionylation and nitration, as well as the binding 2011. motif of the iron-sulfur cluster (N1a) of the complexes I and II were utilized to design B-cell epitopes for generating antibodies. The effect of antibody binding on enzyme-mediated O2*- generation was measured by EPR spin trapping. Binding of either antibody AbGSCA206 or AbGSCB367 against glutathione (GS)-binding domain to complex I inhibit its O2*- generation, but does not affect electron transfer efficiency. Binding of antibody (Ab24N1a) against the binding motif of N1a to complex I modestly suppresses both O2*- generation and electron transfer efficiency. Binding of either antibody Ab75 or Ab24 against nonredox domain decreases electron leakage production. In complex II, binding of antibody AbGSC90 against GS-binding domain to complex II marginally decreases both O2*- generation and electron transfer activity. Binding of antibody AbY142 to complex II against the nitrated domain modestly inhibits electron leakage, but does not affect the electron transfer activity of complex II. In conclusion, mediation of O2*- generation by complexes I and II can be regulated by specific redox and nonredox domains.
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Affiliation(s)
- Patrick T Kang
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, OH 44272 USA
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22
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Gulaboski R, Mirčeski V, Bogeski I, Hoth M. Protein film voltammetry: electrochemical enzymatic spectroscopy. A review on recent progress. J Solid State Electrochem 2011. [DOI: 10.1007/s10008-011-1397-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Fourmond V, Burlat B, Dementin S, Sabaty M, Arnoux P, Étienne É, Guigliarelli B, Bertrand P, Pignol D, Léger C. Dependence of Catalytic Activity on Driving Force in Solution Assays and Protein Film Voltammetry: Insights from the Comparison of Nitrate Reductase Mutants. Biochemistry 2010; 49:2424-32. [DOI: 10.1021/bi902140e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vincent Fourmond
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Bénédicte Burlat
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Sébastien Dementin
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Monique Sabaty
- Laboratoire de Bioénergétique Cellulaire, Commissariat à l’Energie Atomique, DSV, IBEB, 13108 Saint-Paul-lez-Durance, France, and Centre National de la Recherche Scientifique, UMR 6191, Biologie Végétale et Microbiologie Environnementale, and Aix-Marseille Université, 13108 Saint-Paul-lez-Durance, France
| | - Pascal Arnoux
- Laboratoire de Bioénergétique Cellulaire, Commissariat à l’Energie Atomique, DSV, IBEB, 13108 Saint-Paul-lez-Durance, France, and Centre National de la Recherche Scientifique, UMR 6191, Biologie Végétale et Microbiologie Environnementale, and Aix-Marseille Université, 13108 Saint-Paul-lez-Durance, France
| | - Émilien Étienne
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Bruno Guigliarelli
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Patrick Bertrand
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - David Pignol
- Laboratoire de Bioénergétique Cellulaire, Commissariat à l’Energie Atomique, DSV, IBEB, 13108 Saint-Paul-lez-Durance, France, and Centre National de la Recherche Scientifique, UMR 6191, Biologie Végétale et Microbiologie Environnementale, and Aix-Marseille Université, 13108 Saint-Paul-lez-Durance, France
| | - Christophe Léger
- Centre National de la Recherche Scientifique, UPR 9036, Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, and Aix-Marseille Université, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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24
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Liu W, Hou S, Zhao ZK. Synthesis and electrochemical behavior of triazole-containing nicotinamide adenine dinucleotide analogs. CAN J CHEM 2010. [DOI: 10.1139/v09-145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The coupling of 2′,3′-di-O-acetyl nicotinamide mononucleotide with 3-butyn-1-ol in the presence of 2,4,6-triisopropylbenzenesulfonyl chloride quantitatively afforded a terminal alkyne-containing intermediate. Furthermore, copper(I)-mediated Huisgen [3 + 2] cycloaddition with a series of azido compounds in a two-phase solvent system gave eight triazole-containing nicotinamide adenine dinucleotide analogs with yields over 88%. The cyclic voltammetric behaviors of these novel analogs were investigated with a glassy carbon electrode, and structural features of these analogs on their electrochemical properties were briefly discussed.
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Affiliation(s)
- Wujun Liu
- Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China
- Dalian National Laboratory of Clean Energy, Dalian 116023, P. R. China
| | - Shuhua Hou
- Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China
- Dalian National Laboratory of Clean Energy, Dalian 116023, P. R. China
| | - Zongbao Kent Zhao
- Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China
- Dalian National Laboratory of Clean Energy, Dalian 116023, P. R. China
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25
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Ono H, Nakamura H, Matsuzaki M. A NADH dehydrogenase ubiquinone flavoprotein is decreased in patients with dilated cardiomyopathy. Intern Med 2010; 49:2039-42. [PMID: 20930427 DOI: 10.2169/internalmedicine.49.3710] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND It is known that patients with myocarditis of unknown etiology and with dilated cardiomyopathy show a high incidence of serum autoantibodies (M7) directed against mitochondrial flavoproteins. The tissue concentration of mitochondrial flavoproteins in the myocardium obtained from patients with dilated cardiomyopathy (DCM) was examined to further investigate the immunopathological mechanism of cardiomyopathy. METHODS AND RESULTS Myocardial tissue specimens were obtained from patients who underwent cardiac catheterization and a subendomyocardial biopsy for the diagnosis of cardiomyopathy. All samples were analyzed by Western blotting. NADH dehydrogenase ubiquinone flavoprotein (NDUFV1) production in the myocardium decreased significantly with DCM, in comparison to fumarate hydratase and flavoprotein SDHA. There was a significant negative-correlation between the left ventricular end-diastolic dimension and NDUFV1 production (R(2)=0.291, p value<0.05). CONCLUSION NDUFV1 may be involved in the pathogenesis of DCM. A defect of mitochondrial NDUFV1 may reduce complex I, which produces most of the superoxide, which is then scavenged by the mitochondrial enzyme Mn-superoxide dismutase to produce H(2)O(2). Exploring the nature of the candidate protein found in the myocardium in this study will provide further insight into the immunological mechanism of DCM.
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Affiliation(s)
- Hitomi Ono
- Department of Medicine, Yamaguchi University, Ube
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26
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Fourmond V, Lautier T, Baffert C, Leroux F, Liebgott PP, Dementin S, Rousset M, Arnoux P, Pignol D, Meynial-Salles I, Soucaille P, Bertrand P, Léger C. Correcting for electrocatalyst desorption and inactivation in chronoamperometry experiments. Anal Chem 2009; 81:2962-8. [PMID: 19298055 DOI: 10.1021/ac8025702] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chronoamperometric experiments with adsorbed electrocatalysts are commonly performed either for analytical purposes or for studying the catalytic mechanism of a redox enzyme. In the context of amperometric sensors, the current may be recorded as a function of time while the analyte concentration is being increased to determine a linearity range. In mechanistic studies of redox enzymes, chronoamperometry proved powerful for untangling the effects of electrode potential and time, which are convoluted in cyclic voltammetric measurements, and for studying the energetics and kinetics of inhibition. In all such experiments, the fact that the catalyst's coverage and/or activity decreases over time distorts the data. This may hide meaningful features, introduce systematic errors, and limit the accuracy of the measurements. We propose a general and surprisingly simple method for correcting for electrocatalyst desorption and inactivation, which greatly increases the precision of chronoamperometric experiments. Rather than subtracting a baseline, this consists in dividing the current, either by a synthetic signal that is proportional to the instant electroactive coverage or by the signal recorded in a control experiment. In the latter, the change in current may result from film loss only or from film loss plus catalyst inactivation. We describe the different strategies for obtaining the control signal by analyzing various data recorded with adsorbed redox enzymes: nitrate reductase, NiFe hydrogenase, and FeFe hydrogenase. In each case we discuss the trustfulness and the benefit of the correction. This method also applies to experiments where electron transfer is mediated, rather than direct, providing the current is proportional to the time-dependent concentration of catalyst.
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Affiliation(s)
- Vincent Fourmond
- Unité de Bioénergétique et Ingénierie des Protéines, IMM, UPR 9036, CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
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27
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ZHANG HN, GUO ZY, GAI PP. Research Progress in Protein Film Voltammetry. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1016/s1872-2040(08)60093-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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28
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29
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Fato R, Bergamini C, Bortolus M, Maniero AL, Leoni S, Ohnishi T, Lenaz G. Differential effects of mitochondrial Complex I inhibitors on production of reactive oxygen species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1787:384-92. [PMID: 19059197 DOI: 10.1016/j.bbabio.2008.11.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 10/29/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
Abstract
We have investigated the production of reactive oxygen species (ROS) by Complex I in isolated open bovine heart submitochondrial membrane fragments during forward electron transfer in presence of NADH, by means of the probe 2',7'-Dichlorodihydrofluorescein diacetate. ROS production by Complex I is strictly related to its inhibited state. Our results indicate that different Complex I inhibitors can be grouped into two classes: Class A inhibitors (Rotenone, Piericidin A and Rolliniastatin 1 and 2) increase ROS production; Class B inhibitors (Stigmatellin, Mucidin, Capsaicin and Coenzyme Q(2)) prevent ROS production also in the presence of Class A inhibitors. Addition of the hydrophilic Coenzyme Q(1) as an electron acceptor potentiates the effect of Rotenone-like inhibitors in increasing ROS production, but has no effect in the presence of Stigmatellin-like inhibitors; the effect is not shared by more hydrophobic quinones such as decyl-ubiquinone. This behaviour relates the prooxidant CoQ(1) activity to a hydrophilic electron escape site. Moreover the two classes of Complex I inhibitors have an opposite effect on the increase of NADH-DCIP reduction induced by short chain quinones: only Class B inhibitors allow this increase, indicating the presence of a Rotenone-sensitive but Stigmatellin-insensitive semiquinone species in the active site of the enzyme. The presence of this semiquinone was also suggested by preliminary EPR data. The results suggest that electron transfer from the iron-sulphur clusters (N2) to Coenzyme Q occurs in two steps gated by two different conformations, the former being sensitive to Rotenone and the latter to Stigmatellin.
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Affiliation(s)
- Romana Fato
- Dipartimento di Biochimica G. Moruzzi, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
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30
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Reda T, Barker CD, Hirst J. Reduction of the iron-sulfur clusters in mitochondrial NADH:ubiquinone oxidoreductase (complex I) by EuII-DTPA, a very low potential reductant. Biochemistry 2008; 47:8885-93. [PMID: 18651753 DOI: 10.1021/bi800437g] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
NADH:ubiquinone oxidoreductase (complex I) is the first enzyme of the mitochondrial electron transport chain. It contains a flavin mononucleotide to oxidize NADH, and eight iron-sulfur clusters. Seven of them transfer electrons between the flavin and the quinone-binding site, and one is on the opposite side of the flavin. Although most information about their properties is from EPR, the spectra from only five clusters have been observed, and it is difficult to match them to the structurally defined clusters. Here, we analyze complex I from bovine mitochondria reacted with a very low potential reductant, to impose a potential approaching -1 V. We compare the spectra with those from higher potentials and from the 24 kDa subunit and flavoprotein subcomplex, and model the spectra by starting from those with fewer components and building the complexity gradually. Spectrum N1a, from the 24 kDa subunit [2Fe-2S] cluster, is not observed in bovine complex I at any potential. Spectrum N1b, from the 75 kDa subunit [2Fe-2S] cluster, exhibits a lower potential than the N3, N4 and N5 spectra of three [4Fe-4S] clusters. In the lowest potential spectra an N5-type spectrum is observed at unusually high temperature (indicating a significant change to the cluster, or that two clusters have very similar g values), the relaxation rate of N1b increases (indicating that a nearby cluster has become reduced) and a new feature with an apparent g value of 2.16 suggests an interaction between two reduced clusters. The consequences of these observations for electron transfer in complex I are discussed.
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Affiliation(s)
- Torsten Reda
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
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31
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Léger C, Bertrand P. Direct Electrochemistry of Redox Enzymes as a Tool for Mechanistic Studies. Chem Rev 2008; 108:2379-438. [DOI: 10.1021/cr0680742] [Citation(s) in RCA: 594] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Cracknell JA, Vincent KA, Armstrong FA. Enzymes as Working or Inspirational Electrocatalysts for Fuel Cells and Electrolysis. Chem Rev 2008; 108:2439-61. [DOI: 10.1021/cr0680639] [Citation(s) in RCA: 846] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Euro L, Bloch DA, Wikström M, Verkhovsky MI, Verkhovskaya M. Electrostatic interactions between FeS clusters in NADH:ubiquinone oxidoreductase (Complex I) from Escherichia coli. Biochemistry 2008; 47:3185-93. [PMID: 18269245 DOI: 10.1021/bi702063t] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The redox properties of the cofactors of NADH:ubiquinone oxidoreductase (complex I) from Escherichia coli were studied by following the changes in electron paramagnetic resonance (EPR) and optical spectra upon electrochemical redox titration of the purified protein. At neutral pH, the FMN cofactor had a midpoint redox potential ( E m) approximately -350 mV ( n = 2). Binuclear FeS clusters were well-characterized: N1a was titrated with a single ( n = 1) transition, and E m = -235 mV. In contrast, the titration of N1b can only be fitted with the sum of at least two one-electron Nernstian curves with E m values of -245 and -320 mV. The tetranuclear clusters can also be separated into two groups, either having a single, n = 1, or more complex redox titration curves. The titration curves of the EPR bands attributed to the tetranuclear clusters N2 ( g = 2.045 and g = 1.895) and N6b ( g = 2.089 and g = 1.877) can be presented by the sum of at least two components, each with E m (app) approximately -200/-300 mV and -235/-315 mV, respectively. The titration of the signals at g = 1.956-1.947 (N3 or N7, E m = -315 mV), g = 2.022, and g = 1.932 (Nx, -365 mV) and the low temperature signal at g = 1.929 (N4 or N5, -330 mV) followed Nernstian n = 1 curves. The observed redox titration curves are discussed in terms of intrinsic electrostatic interactions between FeS centers in complex I. A model showing shifts of E m due to the electrostatic interaction between the centers is presented.
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Affiliation(s)
- Liliya Euro
- Helsinki Bioenergetics Group, Institute of Biotechnology, P.O. Box 65, (Viikinkaari 1) 00014 University of Helsinki, Helsinki, Finland
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34
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Gates AJ, Richardson DJ, Butt JN. Voltammetric characterization of the aerobic energy-dissipating nitrate reductase of Paracoccus pantotrophus: exploring the activity of a redox-balancing enzyme as a function of electrochemical potential. Biochem J 2008; 409:159-68. [PMID: 17900239 DOI: 10.1042/bj20071088] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Paracoccus pantotrophus expresses two nitrate reductases associated with respiratory electron transport, termed NapABC and NarGHI. Both enzymes derive electrons from ubiquinol to reduce nitrate to nitrite. However, while NarGHI harnesses the energy of the quinol/nitrate couple to generate a transmembrane proton gradient, NapABC dissipates the energy associated with these reducing equivalents. In the present paper we explore the nitrate reductase activity of purified NapAB as a function of electrochemical potential, substrate concentration and pH using protein film voltammetry. Nitrate reduction by NapAB is shown to occur at potentials below approx. 0.1 V at pH 7. These are lower potentials than required for NarGH nitrate reduction. The potentials required for Nap nitrate reduction are also likely to require ubiquinol/ubiquinone ratios higher than are needed to activate the H(+)-pumping oxidases expressed during aerobic growth where Nap levels are maximal. Thus the operational potentials of P. pantotrophus NapAB are consistent with a productive role in redox balancing. A Michaelis constant (K(M)) of approx. 45 muM was determined for NapAB nitrate reduction at pH 7. This is in line with studies on intact cells where nitrate reduction by Nap was described by a Monod constant (K(S)) of less than 15 muM. The voltammetric studies also disclosed maximal NapAB activity in a narrow window of potential. This behaviour is resistant to change of pH, nitrate concentration and inhibitor concentration and its possible mechanistic origins are discussed.
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Affiliation(s)
- Andrew J Gates
- Centre for Metalloprotein Spectroscopy and Biology, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
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35
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Gostimskaya IS, Grivennikova VG, Cecchini G, Vinogradov AD. Reversible dissociation of flavin mononucleotide from the mammalian membrane-bound NADH: ubiquinone oxidoreductase (complex I). FEBS Lett 2007; 581:5803-6. [PMID: 18037377 DOI: 10.1016/j.febslet.2007.11.048] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 11/14/2007] [Accepted: 11/15/2007] [Indexed: 11/29/2022]
Abstract
Conditions for the reversible dissociation of flavin mononucleotide (FMN) from the membrane-bound mitochondrial NADH:ubiquinone oxidoreductase (complex I) are described. The catalytic activities of the enzyme, i.e. rotenone-insensitive NADH:hexaammineruthenium III reductase and rotenone-sensitive NADH:quinone reductase decline when bovine heart submitochondrial particles are incubated with NADH in the presence of rotenone or cyanide at alkaline pH. FMN protects and fully restores the NADH-induced inactivation whereas riboflavin and flavin adenine dinucleotide do not. The data show that the reduction of complex I significantly weakens the binding of FMN to protein thus resulting in its dissociation when the concentration of holoenzyme is comparable with K(d ( approximately 10(-8)M at pH 10.0).
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Affiliation(s)
- Irina S Gostimskaya
- Department of Biochemistry, School of Biology, Moscow State University, Moscow 119992, Russian Federation
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Grivennikova VG, Kotlyar AB, Karliner JS, Cecchini G, Vinogradov AD. Redox-dependent change of nucleotide affinity to the active site of the mammalian complex I. Biochemistry 2007; 46:10971-8. [PMID: 17760425 PMCID: PMC2258335 DOI: 10.1021/bi7009822] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A very potent and specific inhibitor of mitochondrial NADH:ubiquinone oxidoreductase (complex I), a derivative of NADH (NADH-OH) has recently been discovered (Kotlyar, A. B., Karliner, J. S., and Cecchini, G. (2005) FEBS Lett. 579, 4861-4866). Here we present a quantitative analysis of the interaction of NADH-OH and other nucleotides with oxidized and reduced complex I in tightly coupled submitochondrial particles. Both the rate of the NADH-OH binding and its affinity to complex I are strongly decreased in the presence of succinate. The effect of succinate is completely reversed by rotenone, antimycin A, and uncoupler. The relative affinity of ADP-ribose, a competitive inhibitor of NADH oxidation, is also shown to be significantly affected by enzyme reduction (KD of 30 and 500 microM for oxidized and the succinate-reduced enzyme, respectively). Binding of NADH-OH is shown to abolish the succinate-supported superoxide generation by complex I. Gradual inhibition of the rotenone-sensitive uncoupled NADH oxidase and the reverse electron transfer activities by NADH-OH yield the same final titration point (approximately 0.1 nmol/mg of protein). The titration of NADH oxidase appears as a straight line, whereas the titration of the reverse reaction appears as a convex curve. Possible models to explain the different titration patterns for the forward and reverse reactions are briefly discussed.
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Affiliation(s)
| | - Alexander B. Kotlyar
- * To whom correspondence should be addressed. (A.D.V.) Phone/fax: 7 495 939 1376. E-mail: . (A.B.K.) Phone: (415) 221-4810 ext. 3416. Fax: (415) 750-6959. E-mail:
| | | | | | - Andrei D. Vinogradov
- * To whom correspondence should be addressed. (A.D.V.) Phone/fax: 7 495 939 1376. E-mail: . (A.B.K.) Phone: (415) 221-4810 ext. 3416. Fax: (415) 750-6959. E-mail:
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Bertrand P, Frangioni B, Dementin S, Sabaty M, Arnoux P, Guigliarelli B, Pignol D, Léger C. Effects of Slow Substrate Binding and Release in Redox Enzymes: Theory and Application to Periplasmic Nitrate Reductase. J Phys Chem B 2007; 111:10300-11. [PMID: 17676894 DOI: 10.1021/jp074340j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For redox enzymes, the technique called protein film voltammetry makes it possible to determine the entire profile of activity against driving force by having the enzyme exchanging directly electrons with the rotating-disc electrode onto which it is adsorbed. Both the potential location of the catalytic response and its detailed shape report on the sequence of catalytic events, electron transfers and chemical steps, but the models that have been used so far to decipher this signal lack generality. For example, it was often proposed that substrate binding to multiple redox states of the active site may explain that turnover is greater in a certain window of electrode potential, but no fully analytical treatment has been given. Here, we derive (i) the general current equation for the case of reversible substrate binding to any redox states of a two-electron active site (as exemplified by flavins and Mo cofactors), (ii) the quantitative conditions for an extremum in activity to occur, and (iii) the expressions from which the substrate-concentration dependence of the catalytic potential can be interpreted to learn about the kinetics of substrate binding and how this affects the reduction potential of the active site. Not only does slow substrate binding and release make the catalytic wave shape highly complex, but we also show that it can have important consequences which will escape detection in traditional experiments: the position of the wave (this is the driving force that is required to elicit catalysis) departs from the reduction potential of the active site even at the lowest substrate concentration, and this deviation may be large if substrate binding is irreversible. This occurs in the reductive half-cycle of periplasmic nitrate reductase where irreversibility lowers the driving force required to reduce the active site under turnover conditions and favors intramolecular electron transfer from the proximal [4Fe4S]+ cluster to the active site Mo(V).
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Affiliation(s)
- Patrick Bertrand
- Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS UPR 9036, IBSM, France
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Yakovlev G, Reda T, Hirst J. Reevaluating the relationship between EPR spectra and enzyme structure for the iron sulfur clusters in NADH:quinone oxidoreductase. Proc Natl Acad Sci U S A 2007; 104:12720-5. [PMID: 17640900 PMCID: PMC1925037 DOI: 10.1073/pnas.0705593104] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
NADH:quinone oxidoreductase (complex I) plays a pivotal role in cellular energy production. It employs a series of redox cofactors to couple electron transfer to the generation of a proton-motive force across the inner mitochondrial or bacterial cytoplasmic membrane. Complex I contains a noncovalently bound flavin mononucleotide at the active site for NADH oxidation and eight or nine iron-sulfur clusters to transfer electrons between the flavin and a quinone-binding site. Understanding the mechanism of complex I requires the properties of these clusters to be defined, both individually and as an ensemble. Most functional information on the clusters has been gained from EPR spectroscopy, but some clusters are not observed by EPR and attributing the observed signals to the structurally defined clusters is difficult. The current consensus picture relies on correlating the spectra from overexpressed subunits (containing one to four clusters) with those from intact complexes I. Here, we analyze spectra from the overexpressed NuoG subunit from Escherichia coli complex I and compare them with spectra from the intact enzyme. Consequently, we propose that EPR signals N4 and N5 have been misassigned: signal N4 is from NuoI (not NuoG) and signal N5 is from the conserved cysteine-ligated [4Fe-4S] cluster in NuoG (not from the cluster with a histidine ligand). The consequences of reassigning the EPR signals and their associated functional information on the free energy profile for electron transfer through complex I are discussed.
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Affiliation(s)
- Gregory Yakovlev
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, United Kingdom
| | - Torsten Reda
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, United Kingdom
| | - Judy Hirst
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, United Kingdom
- To whom correspondence should be addressed. E-mail:
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