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Lobez AP, Wu F, Di Trani JM, Rubinstein JL, Oliveberg M, Brzezinski P, Moe A. Electron transfer in the respiratory chain at low salinity. Nat Commun 2024; 15:8241. [PMID: 39300056 DOI: 10.1038/s41467-024-52475-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 09/09/2024] [Indexed: 09/22/2024] Open
Abstract
Recent studies have established that cellular electrostatic interactions are more influential than assumed previously. Here, we use cryo-EM and perform steady-state kinetic studies to investigate electrostatic interactions between cytochrome (cyt.) c and the complex (C) III2-IV supercomplex from Saccharomyces cerevisiae at low salinity. The kinetic studies show a sharp transition with a Hill coefficient ≥2, which together with the cryo-EM data at 2.4 Å resolution indicate multiple cyt. c molecules bound along the supercomplex surface. Negatively charged loops of CIII2 subunits Qcr6 and Qcr9 become structured to interact with cyt. c. In addition, the higher resolution allows us to identify water molecules in proton pathways of CIV and, to the best of our knowledge, previously unresolved cardiolipin molecules. In conclusion, the lowered electrostatic screening renders engagement of multiple cyt. c molecules that are directed by electrostatically structured CIII2 loops to conduct electron transfer between CIII2 and CIV.
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Affiliation(s)
- Ana Paula Lobez
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Fei Wu
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Justin M Di Trani
- Molecular Medicine program, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario, Canada
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - John L Rubinstein
- Molecular Medicine program, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario, Canada
- Department of Medical Biophysics, The University of Toronto, 101 College Street, Toronto, Ontario, Canada
- Department of Biochemistry, The University of Toronto, 1 Kings College Circle, Toronto, Ontario, Canada
| | - Mikael Oliveberg
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden.
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden.
| | - Agnes Moe
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden.
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, Bern, Switzerland.
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Smirnova I, Wu F, Brzezinski P. Stimulation of cytochrome c oxidase activity by detergents. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1866:149509. [PMID: 39251013 DOI: 10.1016/j.bbabio.2024.149509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 09/05/2024] [Accepted: 09/05/2024] [Indexed: 09/11/2024]
Abstract
Cytochrome c oxidase (CytcO) is an integral membrane protein, which catalyzes four-electron reduction of oxygen linked to proton uptake and pumping. Amphipathic molecules bind in sites near the so-called K proton pathway of CytcO to reversibly modulate its activity. However, purification of CytcO for mechanistic studies typically involves the use of detergents, which may interfere with binding of these regulatory molecules. Here, we investigated the CytcO enzymatic activity as well as intramolecular electron transfer linked to proton transfer upon addition of different detergents to bovine heart mitoplasts. The CytcO activity increased upon addition of alkyl glucosides (DDM and DM) and the steroid analog GDN. The maximum stimulating effect was observed for DDM and DM, and the half-stimulating effect correlated with their CMC values. With GDN the stimulation effect was smaller and occurred at a concentration higher than CMC. A kinetic analysis suggests that the stimulation of activity is due to removal of a ligand bound near the K proton pathway, which indicates that in the native membrane this site is occupied to yield a lower than maximal possible CytcO activity. Possible functional consequences are discussed.
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Affiliation(s)
- Irina Smirnova
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Fei Wu
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
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Dinh N, Bonnefoy N. Schizosaccharomyces pombe as a fundamental model for research on mitochondrial gene expression: Progress, achievements and outlooks. IUBMB Life 2024; 76:397-419. [PMID: 38117001 DOI: 10.1002/iub.2801] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023]
Abstract
Schizosaccharomyces pombe (fission yeast) is an attractive model for mitochondrial research. The organism resembles human cells in terms of mitochondrial inheritance, mitochondrial transport, sugar metabolism, mitogenome structure and dependence of viability on the mitogenome (the petite-negative phenotype). Transcriptions of these genomes produce only a few polycistronic transcripts, which then undergo processing as per the tRNA punctuation model. In general, the machinery for mitochondrial gene expression is structurally and functionally conserved between fission yeast and humans. Furthermore, molecular research on S. pombe is supported by a considerable number of experimental techniques and database resources. Owing to these advantages, fission yeast has significantly contributed to biomedical and fundamental research. Here, we review the current state of knowledge regarding S. pombe mitochondrial gene expression, and emphasise the pertinence of fission yeast as both a model and tool, especially for studies on mitochondrial translation.
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Affiliation(s)
- Nhu Dinh
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette cedex, France
| | - Nathalie Bonnefoy
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette cedex, France
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Eldeeb MH, Camacho Lopez LJ, Fontanesi F. Mitochondrial respiratory supercomplexes of the yeast Saccharomyces cerevisiae. IUBMB Life 2024. [PMID: 38529880 DOI: 10.1002/iub.2817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/28/2024] [Indexed: 03/27/2024]
Abstract
The functional and structural relationship among the individual components of the mitochondrial respiratory chain constitutes a central aspect of our understanding of aerobic catabolism. This interplay has been a subject of intense debate for over 50 years. It is well established that individual respiratory enzymes associate into higher-order structures known as respiratory supercomplexes, which represent the evolutionarily conserved organizing principle of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, supercomplexes are formed by a complex III homodimer flanked by one or two complex IV monomers, and their high-resolution structures have been recently elucidated. Despite the wealth of structural information, several proposed supercomplex functions remain speculative and our understanding of their physiological relevance is still limited. Recent advances in the field were made possible by the construction of yeast strains where the association of complex III and IV into supercomplexes is impeded, leading to diminished respiratory capacity and compromised cellular competitive fitness. Here, we discuss the experimental evidence and hypotheses relative to the functional roles of yeast respiratory supercomplexes. Moreover, we review the current models of yeast complex III and IV assembly in the context of supercomplex formation and highlight the data scattered throughout the literature suggesting the existence of cross talk between their biogenetic processes.
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Affiliation(s)
- Mazzen H Eldeeb
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Lizeth J Camacho Lopez
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
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Nastasi MR, Borisov VB, Forte E. Membrane-Bound Redox Enzyme Cytochrome bd-I Promotes Carbon Monoxide-Resistant Escherichia coli Growth and Respiration. Int J Mol Sci 2024; 25:1277. [PMID: 38279276 PMCID: PMC10815991 DOI: 10.3390/ijms25021277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/23/2023] [Accepted: 01/18/2024] [Indexed: 01/28/2024] Open
Abstract
The terminal oxidases of bacterial aerobic respiratory chains are redox-active electrogenic enzymes that catalyze the four-electron reduction of O2 to 2H2O taking out electrons from quinol or cytochrome c. Living bacteria often deal with carbon monoxide (CO) which can act as both a signaling molecule and a poison. Bacterial terminal oxidases contain hemes; therefore, they are potential targets for CO. However, our knowledge of this issue is limited and contradictory. Here, we investigated the effect of CO on the cell growth and aerobic respiration of three different Escherichia coli mutants, each expressing only one terminal quinol oxidase: cytochrome bd-I, cytochrome bd-II, or cytochrome bo3. We found that following the addition of CO to bd-I-only cells, a minimal effect on growth was observed, whereas the growth of both bd-II-only and bo3-only strains was severely impaired. Consistently, the degree of resistance of aerobic respiration of bd-I-only cells to CO is high, as opposed to high CO sensitivity displayed by bd-II-only and bo3-only cells consuming O2. Such a difference between the oxidases in sensitivity to CO was also observed with isolated membranes of the mutants. Accordingly, O2 consumption of wild-type cells showed relatively low CO sensitivity under conditions favoring the expression of a bd-type oxidase.
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Affiliation(s)
- Martina R. Nastasi
- Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy;
| | - Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy;
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