1
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Monti E, Mancini A, Marras E, Gariboldi MB. Targeting Mitochondrial ROS Production to Reverse the Epithelial-Mesenchymal Transition in Breast Cancer Cells. Curr Issues Mol Biol 2022; 44:5277-5293. [PMID: 36354671 PMCID: PMC9689492 DOI: 10.3390/cimb44110359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 03/03/2024] Open
Abstract
Experimental evidence implicates reactive oxygen species (ROS) generation in the hypoxic stabilization of hypoxia-inducible factor (HIF)-1α and in the subsequent expression of promoters of tumor invasiveness and metastatic spread. However, the role played by mitochondrial ROS in hypoxia-induced Epithelial-Mesenchymal Transition (EMT) activation is still unclear. This study was aimed at testing the hypothesis that the inhibition of hypoxia-induced mitochondrial ROS production, mainly at the mitochondrial Complex III UQCRB site, could result in the reversion of EMT, in addition to decreased HIF-1α stabilization. The role of hypoxia-induced ROS increase in HIF-1α stabilization and the ability of antioxidants, some of which directly targeting mitochondrial Complex III, to block ROS production and HIF-1α stabilization and prevent changes in EMT markers were assessed by evaluating ROS, HIF-1α and EMT markers on breast cancer cells, following 48 h treatment with the antioxidants. The specific role of UQCRB in hypoxia-induced EMT was also evaluated by silencing its expression through RNA interference and by assessing the effects of its downregulation on ROS production, HIF-1α levels, and EMT markers. Our results confirm the pivotal role of UQCRB in hypoxic signaling inducing EMT. Thus, UQCRB might be a new therapeutic target for the development of drugs able to reverse EMT by blocking mitochondrial ROS production.
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Affiliation(s)
- Elena Monti
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
| | - Alessandro Mancini
- Department of Translational Medical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
- BioUp Sagl, 6900 Lugano, Switzerland
| | - Emanuela Marras
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
| | - Marzia Bruna Gariboldi
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
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2
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Capitanio G, Papa F, Papa S. The allosteric protein interactions in the proton-motive function of mammalian redox enzymes of the respiratory chain. Biochimie 2021; 189:1-12. [PMID: 34097987 DOI: 10.1016/j.biochi.2021.05.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/17/2021] [Accepted: 05/31/2021] [Indexed: 12/22/2022]
Abstract
Insight into mammalian respiratory complexes defines the role of allosteric protein interactions in their proton-motive activity. In cytochrome c oxidase (CxIV) conformational change of subunit I, caused by O2 binding to heme a32+-CuB+ and reduction, and stereochemical transitions coupled to oxidation/reduction of heme a and CuA, combined with electrostatic effects, determine the proton pumping activity. In ubiquinone-cytochrome c oxidoreductase (CxIII) conformational movement of Fe-S protein between cytochromes b and c1 is the key element of the proton-motive activity. In NADH-ubiquinone oxidoreductase (CxI) ubiquinone binding and reduction result in conformational changes of subunits in the quinone reaction structure which initiate proton pumping.
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Affiliation(s)
- Giuseppe Capitanio
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124, Bari, Italy.
| | - Francesco Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124, Bari, Italy.
| | - Sergio Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124, Bari, Italy; Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121, Napoli, Italy.
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3
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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4
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Sarewicz M, Pintscher S, Pietras R, Borek A, Bujnowicz Ł, Hanke G, Cramer WA, Finazzi G, Osyczka A. Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes. Chem Rev 2021; 121:2020-2108. [PMID: 33464892 PMCID: PMC7908018 DOI: 10.1021/acs.chemrev.0c00712] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/16/2022]
Abstract
This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc1 and b6f (Cytbc1/b6f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc1/b6f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc1/b6f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc1/b6f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.
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Affiliation(s)
- Marcin Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Sebastian Pintscher
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Arkadiusz Borek
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Łukasz Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Guy Hanke
- School
of Biological and Chemical Sciences, Queen
Mary University of London, London E1 4NS, U.K.
| | - William A. Cramer
- Department
of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 United States
| | - Giovanni Finazzi
- Laboratoire
de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, Centre National Recherche Scientifique,
Commissariat Energie Atomique et Energies Alternatives, Institut National
Recherche l’agriculture, l’alimentation et l’environnement, 38054 Grenoble Cedex 9, France
| | - Artur Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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5
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Maldonado M, Guo F, Letts JA. Atomic structures of respiratory complex III 2, complex IV, and supercomplex III 2-IV from vascular plants. eLife 2021; 10:e62047. [PMID: 33463523 PMCID: PMC7815315 DOI: 10.7554/elife.62047] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial complex III (CIII2) and complex IV (CIV), which can associate into a higher-order supercomplex (SC III2+IV), play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII2, CIV, and SC III2+IV from Vigna radiata determined by single-particle cryoEM. The structures reveal plant-specific differences in the MPP domain of CIII2 and define the subunit composition of CIV. Conformational heterogeneity analysis of CIII2 revealed long-range, coordinated movements across the complex, as well as the motion of CIII2's iron-sulfur head domain. The CIV structure suggests that, in plants, proton translocation does not occur via the H channel. The supercomplex interface differs significantly from that in yeast and bacteria in its interacting subunits, angle of approach and limited interactions in the mitochondrial matrix. These structures challenge long-standing assumptions about the plant complexes and generate new mechanistic hypotheses.
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Affiliation(s)
- Maria Maldonado
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
| | - Fei Guo
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
- BIOEM Facility, University of California DavisDavisUnited States
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
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6
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Wise CE, Ledinina AE, Yuly JL, Artz JH, Lubner CE. The role of thermodynamic features on the functional activity of electron bifurcating enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148377. [PMID: 33453185 DOI: 10.1016/j.bbabio.2021.148377] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 11/25/2022]
Abstract
Electron bifurcation is a biological mechanism to drive a thermodynamically unfavorable redox reaction through direct coupling with an exergonic reaction. This process allows microorganisms to generate high energy reducing equivalents in order to sustain life and is often found in anaerobic metabolism, where the energy economy of the cell is poor. Recent work has revealed details of the redox energy landscapes for a variety of electron bifurcating enzymes, greatly expanding the understanding of how energy is transformed by this unique mechanism. Here we highlight the plasticity of these emerging landscapes, what is known regarding their mechanistic underpinnings, and provide a context for interpreting their biochemical activity within the physiological framework. We conclude with an outlook for propelling the field toward an integrative understanding of the impact of electron bifurcation.
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Affiliation(s)
| | | | | | - Jacob H Artz
- National Renewable Energy Laboratory, Golden, CO, USA
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7
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Peters JW, Beratan DN, Bothner B, Dyer RB, Harwood CS, Heiden ZM, Hille R, Jones AK, King PW, Lu Y, Lubner CE, Minteer SD, Mulder DW, Raugei S, Schut GJ, Seefeldt LC, Tokmina-Lukaszewska M, Zadvornyy OA, Zhang P, Adams MW. A new era for electron bifurcation. Curr Opin Chem Biol 2018; 47:32-38. [PMID: 30077080 DOI: 10.1016/j.cbpa.2018.07.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/16/2018] [Accepted: 07/18/2018] [Indexed: 11/17/2022]
Abstract
Electron bifurcation, or the coupling of exergonic and endergonic oxidation-reduction reactions, was discovered by Peter Mitchell and provides an elegant mechanism to rationalize and understand the logic that underpins the Q cycle of the respiratory chain. Thought to be a unique reaction of respiratory complex III for nearly 40 years, about a decade ago Wolfgang Buckel and Rudolf Thauer discovered that flavin-based electron bifurcation is also an important component of anaerobic microbial metabolism. Their discovery spawned a surge of research activity, providing a basis to understand flavin-based bifurcation, forging fundamental parallels with Mitchell's Q cycle and leading to the proposal of metal-based bifurcating enzymes. New insights into the mechanism of electron bifurcation provide a foundation to establish the unifying principles and essential elements of this fascinating biochemical phenomenon.
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Affiliation(s)
- John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman WA 99163, United States; Pacific Northwest National Laboratory, Richland, WA 99352, United States.
| | - David N Beratan
- Department of Chemistry and Department of Physics, Duke University, Durham, NC 27708, United States; Department of Biochemistry, Duke University, Durham, NC 27710, United States
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, GA 30322, United States
| | - Caroline S Harwood
- Department of Microbiology, University of Washington, Seattle, WA 98195, United States
| | - Zachariah M Heiden
- Department of Chemistry, Washington State University, Pullman WA 99163, United States
| | - Russ Hille
- Biochemistry Department, University of California at Riverside, Riverside, CA 92521, United States
| | - Anne K Jones
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, United States
| | - Paul W King
- National Renewable Energy Laboratory, Golden, CO 8040, United States
| | - Yi Lu
- Pacific Northwest National Laboratory, Richland, WA 99352, United States; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Carolyn E Lubner
- National Renewable Energy Laboratory, Golden, CO 8040, United States
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, United States
| | - David W Mulder
- National Renewable Energy Laboratory, Golden, CO 8040, United States
| | - Simone Raugei
- Institute of Biological Chemistry, Washington State University, Pullman WA 99163, United States; Pacific Northwest National Laboratory, Richland, WA 99352, United States
| | - Gerrit J Schut
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, United States
| | - Lance C Seefeldt
- Pacific Northwest National Laboratory, Richland, WA 99352, United States; Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, United States
| | | | - Oleg A Zadvornyy
- Institute of Biological Chemistry, Washington State University, Pullman WA 99163, United States
| | - Peng Zhang
- Department of Biochemistry, Duke University, Durham, NC 27710, United States
| | - Michael Ww Adams
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, United States
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8
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Pintscher S, Pietras R, Sarewicz M, Osyczka A. Electron sweep across four b-hemes of cytochrome bc1 revealed by unusual paramagnetic properties of the Qi semiquinone intermediate. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:459-469. [DOI: 10.1016/j.bbabio.2018.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/08/2018] [Accepted: 03/18/2018] [Indexed: 01/05/2023]
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9
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Papa S, Capitanio G, Papa F. The mechanism of coupling between oxido-reduction and proton translocation in respiratory chain enzymes. Biol Rev Camb Philos Soc 2017. [DOI: 10.1111/brv.12347] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Sergio Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
- Institute of Biomembranes and Bioenergetics; National Research Council at BMSNSO; Piazza G. Cesare 11 70124 Bari Italy
| | - Giuseppe Capitanio
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
| | - Francesco Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
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10
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Tooke FJ, Babot M, Chandra G, Buchanan G, Palmer T. A unifying mechanism for the biogenesis of membrane proteins co-operatively integrated by the Sec and Tat pathways. eLife 2017; 6. [PMID: 28513434 PMCID: PMC5449189 DOI: 10.7554/elife.26577] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 05/15/2017] [Indexed: 11/13/2022] Open
Abstract
The majority of multi-spanning membrane proteins are co-translationally inserted into the bilayer by the Sec pathway. An important subset of membrane proteins have globular, cofactor-containing extracytoplasmic domains requiring the dual action of the co-translational Sec and post-translational Tat pathways for integration. Here, we identify further unexplored families of membrane proteins that are dual Sec-Tat-targeted. We establish that a predicted heme-molybdenum cofactor-containing protein, and a complex polyferredoxin, each require the concerted action of two translocases for their assembly. We determine that the mechanism of handover from Sec to Tat pathway requires the relatively low hydrophobicity of the Tat-dependent transmembrane domain. This, coupled with the presence of C-terminal positive charges, results in abortive insertion of this transmembrane domain by the Sec pathway and its subsequent release at the cytoplasmic side of the membrane. Together, our data points to a simple unifying mechanism governing the assembly of dual targeted membrane proteins.
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Affiliation(s)
- Fiona J Tooke
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Marion Babot
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Grant Buchanan
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Tracy Palmer
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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11
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Stiban J, So M, Kaguni LS. Iron-Sulfur Clusters in Mitochondrial Metabolism: Multifaceted Roles of a Simple Cofactor. BIOCHEMISTRY (MOSCOW) 2017; 81:1066-1080. [PMID: 27908232 DOI: 10.1134/s0006297916100059] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron-sulfur metabolism is essential for cellular function and is a key process in mitochondria. In this review, we focus on the structure and assembly of mitochondrial iron-sulfur clusters and their roles in various metabolic processes that occur in mitochondria. Iron-sulfur clusters are crucial in mitochondrial respiration, in which they are required for the assembly, stability, and function of respiratory complexes I, II, and III. They also serve important functions in the citric acid cycle, DNA metabolism, and apoptosis. Whereas the identification of iron-sulfur containing proteins and their roles in numerous aspects of cellular function has been a long-standing research area, that in mitochondria is comparatively recent, and it is likely that their roles within mitochondria have been only partially revealed. We review the status of the field and provide examples of other cellular iron-sulfur proteins to highlight their multifarious roles.
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Affiliation(s)
- Johnny Stiban
- Birzeit University, Department of Biology and Biochemistry, West Bank Birzeit, 627, Palestine.
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12
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Shirey K, Stover KR, Cleary J, Hoang N, Hosler J. Membrane-Anchored Cyclic Peptides as Effectors of Mitochondrial Oxidative Phosphorylation. Biochemistry 2016; 55:2100-11. [PMID: 26985698 DOI: 10.1021/acs.biochem.5b01368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The echinocandins are membrane-anchored, cyclic lipopeptides (CLPs) with antifungal activity due to their ability to inhibit a glucan synthase located in the plasma membrane of fungi such as Candida albicans. A hydrophobic tail of an echinocandin CLP inserts into a membrane, placing a six-amino acid cyclic peptide near the membrane surface. Because processes critical for the function of the electron transfer complexes of mitochondria, such as proton uptake and release, take place near the surface of the membrane, we have tested the ability of two echinocandin CLPs, caspofungin and micafungin, to affect the activity of electron transfer complexes in isolated mammalian mitochondria. Indeed, caspofungin and micafungin both inhibit whole chain electron transfer in isolated mitochondria at low micromolar concentrations. The effects of the CLPs are fully reversible, in some cases simply via the addition of bovine serum albumin to bind the CLPs via their hydrophobic tails. Each CLP affects more than one complex, but they still exhibit specificity of action. Only caspofungin inhibits complex I, and the CLP inhibits liver but not heart complex I. Both CLPs inhibit heart and liver complex III. Caspofungin inhibits complex IV activity, while, remarkably, micafungin stimulates complex IV activity nearly 3-fold. Using a variety of assays, we have developed initial hypotheses for the mechanisms by which caspofungin and micafungin alter the activities of complexes IV and III. The dication caspofungin partially inhibits cytochrome c binding at the low-affinity binding site of complex IV, while it also appears to inhibit the release of protons from the outer surface of the complex, similar to Zn(2+). Anionic micafungin appears to stimulate complex IV activity by enhancing the transfer of protons to the O2 reduction site. For complex III, we hypothesize that each CLP binds to the cytochrome b subunit and the Fe-S subunit to inhibit the required rotational movement of the latter.
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Affiliation(s)
- Kristin Shirey
- Department of Biochemistry and ‡School of Pharmacy, University of Mississippi Medical Center , 2500 North State Street, Jackson, Mississippi 39216, United States
| | - Kayla R Stover
- Department of Biochemistry and ‡School of Pharmacy, University of Mississippi Medical Center , 2500 North State Street, Jackson, Mississippi 39216, United States
| | - John Cleary
- Department of Biochemistry and ‡School of Pharmacy, University of Mississippi Medical Center , 2500 North State Street, Jackson, Mississippi 39216, United States
| | - Ngoc Hoang
- Department of Biochemistry and ‡School of Pharmacy, University of Mississippi Medical Center , 2500 North State Street, Jackson, Mississippi 39216, United States
| | - Jonathan Hosler
- Department of Biochemistry and ‡School of Pharmacy, University of Mississippi Medical Center , 2500 North State Street, Jackson, Mississippi 39216, United States
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13
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Song Z, Clain J, Iorga BI, Vallières C, Lalève A, Fisher N, Meunier B. Interplay between the hinge region of iron sulphur protein and the Qo site in the bc1 complex - Analysis of Plasmodium-like mutations in the yeast enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1487-94. [PMID: 26301481 DOI: 10.1016/j.bbabio.2015.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/21/2015] [Accepted: 08/19/2015] [Indexed: 10/23/2022]
Abstract
The respiratory chain bc1 complex is central to mitochondrial bioenergetics and the target of antiprotozoals. We characterized a modified yeast bc1 complex that more closely resemble Plasmodium falciparum enzyme. The mutant version was generated by replacing ten cytochrome b Qo site residues by P. falciparum equivalents. The Plasmodium-like changes caused a major dysfunction of the catalytic mechanism of the bc1 complex resulting in superoxide overproduction and respiratory growth defect. The defect was corrected by substitution of the conserved residue Y279 by a phenylalanine, or by mutations in or in the vicinity of the hinge domain of the iron-sulphur protein. It thus appears that side-reactions can be prevented by the substitution Y279F or the modification of the iron-sulphur protein hinge region. Interestingly, P. falciparum - and all the apicomplexan - contains an unusual hinge region. We replaced the yeast hinge region by the Plasmodium version and combined it with the Plasmodium-like version of the Qo site. This combination restored the respiratory growth competence. It could be suggested that, in the apicomplexan, the hinge region and the cytochrome b Qo site have co-evolved to maintain catalytic efficiency of the bc1 complex Qo site.
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Affiliation(s)
- Zehua Song
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif-sur-Yvette, France
| | - Jérôme Clain
- UMR 216, Faculté de Pharmacie de Paris, Université Paris Descartes, and Institut de Recherche pour le Développement, 75006 Paris, France
| | - Bogdan I Iorga
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Labex LERMIT, 91198 Gif-sur-Yvette, France
| | - Cindy Vallières
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif-sur-Yvette, France
| | - Anaïs Lalève
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif-sur-Yvette, France
| | - Nicholas Fisher
- Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA..
| | - Brigitte Meunier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif-sur-Yvette, France.
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14
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Sarewicz M, Osyczka A. Electronic connection between the quinone and cytochrome C redox pools and its role in regulation of mitochondrial electron transport and redox signaling. Physiol Rev 2015; 95:219-43. [PMID: 25540143 PMCID: PMC4281590 DOI: 10.1152/physrev.00006.2014] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria.
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Affiliation(s)
- Marcin Sarewicz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Artur Osyczka
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
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Fu H, Jin M, Ju L, Mao Y, Gao H. Evidence for function overlapping of CymA and the cytochrome bc1 complex in the Shewanella oneidensis nitrate and nitrite respiration. Environ Microbiol 2014; 16:3181-95. [PMID: 24650148 DOI: 10.1111/1462-2920.12457] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/23/2014] [Accepted: 03/16/2014] [Indexed: 11/29/2022]
Abstract
Shewanella oneidensis is an important model organism for its versatility of anaerobic respiration. CymA, a cytoplasmic membrane-bound tetraheme c-type cytochrome, plays a central role in anaerobic respiration by transferring electrons from the quinone pool to a variety of terminal reductases. Although loss of CymA results in defect in respiration of many electron acceptors (EAs), a significant share of the capacity remains in general. In this study, we adopted a transposon random mutagenesis method in a cymA null mutant to identify substituent(s) of CymA with respect to nitrite and nitrate respiration. A total of 87 insertion mutants, whose ability to reduce nitrite was further impaired, were obtained. Among the interrupted genes, the petABC operon appeared to be the most likely candidate given the involvement of the cytochrome bc1 complex that it encodes in electron transport. Subsequent analyses not only confirmed that the complex and CymA were indeed functionally overlapping in nitrate/nitrite respiration but also revealed that both proteins were able to draw electrons from ubiquinone and menaquinone. Furthermore, we found that expression of the bc1 complex was affected by oxygen but not nitrate or nitrite and by global regulators ArcA and Crp in an indirect manner.
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Affiliation(s)
- Huihui Fu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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