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Grzesiuk M, Grabska M, Malinowska A, Świderska B, Grzesiuk E, Garbicz D, Gorecki A. Daphnia stress response to environmental concentrations of chloramphenicol-multi-omics approach. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-35045-4. [PMID: 39317899 DOI: 10.1007/s11356-024-35045-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 09/16/2024] [Indexed: 09/26/2024]
Abstract
Commonly used medicines, when discarded or improperly disposed of, are known to contaminate freshwater ecosystems. Pharmaceuticals can be toxic and mutagenic, and can modify freshwater organisms, even at environmentally relevant concentrations. Chloramphenicol (CAP) is an antibiotic banned in Europe. However, it is still found in surface waters around the world. The aim of this study was to evaluate the impact of chloramphenicol contamination in freshwater on the model organism Daphnia magna. Specific life history parameters, proteome, and host-associated microbiome of four D. magna clones were analyzed during a three-generation exposure to CAP at environmental concentrations (32 ng L-1). In the first generation, no statistically significant CAP effect at the individual level was detected. After three generations, exposed animals were smaller at first reproduction and on average produced fewer offspring. The differences in D. magna's life history after CAP treatment were in accordance with proteome changes. D. magna's response to CAP presence indicates the high stress that the tested organisms are under, e.g., male production, upregulation of ubiquitin-conjugating enzyme E2 and calcium-binding protein, and downregulation of glutathione transferase. The CAP-exposed D. magna proteome profile confirms that CAP, being reactive oxygen species (ROS)-inducing compounds, contributes to structural changes in mitochondria. Microbiome analysis showed a significant difference in the Shannon index between control and CAP-exposed animals, the latter having a more diverse microbiome. Multilevel analyses, together with long exposure in the laboratory imitating conditions in a polluted environment, allow us to obtain a more complete picture of the impact of CAP on D. magna.
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Affiliation(s)
- Malgorzata Grzesiuk
- Department of Biochemistry and Microbiology, Institute of Biology; Warsaw, University of Life Sciences (SGGW), Warsaw, Poland.
| | - Marta Grabska
- Department of Biochemistry and Microbiology, Institute of Biology; Warsaw, University of Life Sciences (SGGW), Warsaw, Poland
| | - Agata Malinowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Bianka Świderska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Elzbieta Grzesiuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Damian Garbicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
- Maria Sklodowska-Curie National Research Institute of Oncology, Roentgena 5, Warsaw, Poland
| | - Adrian Gorecki
- Department of Biochemistry and Microbiology, Institute of Biology; Warsaw, University of Life Sciences (SGGW), Warsaw, Poland
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2
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Pagacz J, Borek A, Osyczka A. ROS production by cytochrome bc 1: Its mechanism as inferred from the effects of heme b cofactor mutants. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1866:149513. [PMID: 39326544 DOI: 10.1016/j.bbabio.2024.149513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/10/2024] [Accepted: 09/23/2024] [Indexed: 09/28/2024]
Abstract
Cytochrome bc1 is one of the enzymes of electron transport chain responsible for generation of reactive oxygen species (ROS). While ROS are considered to be products of side reactions of quinol oxidation site (Qo), molecular aspects of their generation remain unclear. One of them concerns significance of hemes b (bL and bH) redox potentials (Em) and properties on ROS generation by Qo. Here we addressed this question by examining ROS production in mutants of bacterial cytochrome bc1 that replaced one of the His ligand of either heme bL or bH with Lys or Asn. We observed that severe slowing down of electron flow by the Asn mutants induces similar effects on ROS production as inhibition by antimycin in the native cytochrome bc1 (WT). An increase in the Em of hemes b (either bL or bH) in Lys mutants does not exert major effect on the ROS production level, compared to WT. The experimental data were analyzed in the frame of a dynamic model to conclude that the observed ROS rates and levels reflect a combinatory effect of two factors: probability of heme bL being in the reduced state and probability of electron transfer from heme bL towards Qo. A significant contribution from short-circuits maintains the ROS levels at ~15 % in all tested forms. Overall, ROS production by cytochrome bc1 shows remarkably low susceptibility to changes in the Em of heme b cofactors, leaving significance of tuning the Em of hemes b as factor limiting superoxide production an open question.
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Affiliation(s)
- Jakub Pagacz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-087 Krakow, Poland
| | - Arkadiusz Borek
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-087 Krakow, Poland
| | - Artur Osyczka
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-087 Krakow, Poland.
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3
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Ježek P, Jabůrek M, Holendová B, Engstová H, Dlasková A. Mitochondrial Cristae Morphology Reflecting Metabolism, Superoxide Formation, Redox Homeostasis, and Pathology. Antioxid Redox Signal 2023; 39:635-683. [PMID: 36793196 PMCID: PMC10615093 DOI: 10.1089/ars.2022.0173] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023]
Abstract
Significance: Mitochondrial (mt) reticulum network in the cell possesses amazing ultramorphology of parallel lamellar cristae, formed by the invaginated inner mitochondrial membrane. Its non-invaginated part, the inner boundary membrane (IBM) forms a cylindrical sandwich with the outer mitochondrial membrane (OMM). Crista membranes (CMs) meet IBM at crista junctions (CJs) of mt cristae organizing system (MICOS) complexes connected to OMM sorting and assembly machinery (SAM). Cristae dimensions, shape, and CJs have characteristic patterns for different metabolic regimes, physiological and pathological situations. Recent Advances: Cristae-shaping proteins were characterized, namely rows of ATP-synthase dimers forming the crista lamella edges, MICOS subunits, optic atrophy 1 (OPA1) isoforms and mitochondrial genome maintenance 1 (MGM1) filaments, prohibitins, and others. Detailed cristae ultramorphology changes were imaged by focused-ion beam/scanning electron microscopy. Dynamics of crista lamellae and mobile CJs were demonstrated by nanoscopy in living cells. With tBID-induced apoptosis a single entirely fused cristae reticulum was observed in a mitochondrial spheroid. Critical Issues: The mobility and composition of MICOS, OPA1, and ATP-synthase dimeric rows regulated by post-translational modifications might be exclusively responsible for cristae morphology changes, but ion fluxes across CM and resulting osmotic forces might be also involved. Inevitably, cristae ultramorphology should reflect also mitochondrial redox homeostasis, but details are unknown. Disordered cristae typically reflect higher superoxide formation. Future Directions: To link redox homeostasis to cristae ultramorphology and define markers, recent progress will help in uncovering mechanisms involved in proton-coupled electron transfer via the respiratory chain and in regulation of cristae architecture, leading to structural determination of superoxide formation sites and cristae ultramorphology changes in diseases. Antioxid. Redox Signal. 39, 635-683.
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Affiliation(s)
- Petr Ježek
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Martin Jabůrek
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Blanka Holendová
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Hana Engstová
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Andrea Dlasková
- Department No. 75, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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4
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The evolution of the human mitochondrial bc1 complex- adaptation for reduced rate of superoxide production? J Bioenerg Biomembr 2023; 55:15-31. [PMID: 36737563 DOI: 10.1007/s10863-023-09957-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023]
Abstract
The mitochondrial bc1 complex is a major source of mitochondrial superoxide. While bc1-generated superoxide plays a beneficial signaling role, excess production of superoxide lead to aging and degenerative diseases. The catalytic core of bc1 comprises three peptides -cytochrome b, Fe-S protein, and cytochrome c1. All three core peptides exhibit accelerated evolution in anthropoid primates. It has been suggested that the evolution of cytochrome b in anthropoids was driven by a pressure to reduce the production of superoxide. In humans, the bc1 core peptides exhibit anthropoid-specific substitutions that are clustered near functionally critical sites that may affect the production of superoxide. Here we compare the high-resolution structures of bovine, mouse, sheep and human bc1 to identify structural changes that are associated with human-specific substitutions. Several cytochrome b substitutions in humans alter its interactions with other subunits. Most significantly, there is a cluster of seven substitutions, in cytochrome b, the Fe-S protein, and cytochrome c1 that affect the interactions between these proteins at the tether arm of the Fe-S protein and may alter the rate of ubiquinone oxidation and the rate of superoxide production. Another cluster of substitutions near heme bH and the ubiquinone reduction site, Qi, may affect the rate of ubiquinone reduction and thus alter the rate of superoxide production. These results are compatible with the hypothesis that cytochrome b in humans (and other anthropoid primates) evolve to reduce the rate of production of superoxide thus enabling the exceptional longevity and exceptional cognitive ability of humans.
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Wieferig JP, Kühlbrandt W. Analysis of the conformational heterogeneity of the Rieske iron-sulfur protein in complex III 2 by cryo-EM. IUCRJ 2023; 10:27-37. [PMID: 36598500 PMCID: PMC9812224 DOI: 10.1107/s2052252522010570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Movement of the Rieske domain of the iron-sulfur protein is essential for intramolecular electron transfer within complex III2 (CIII2) of the respiratory chain as it bridges a gap in the cofactor chain towards the electron acceptor cytochrome c. We present cryo-EM structures of CIII2 from Yarrowia lipolytica at resolutions up to 2.0 Å under different conditions, with different redox states of the cofactors of the high-potential chain. All possible permutations of three primary positions were observed, indicating that the two halves of the dimeric complex act independently. Addition of the substrate analogue decylubiquinone to CIII2 with a reduced high-potential chain increased the occupancy of the Qo site. The extent of Rieske domain interactions through hydrogen bonds to the cytochrome b and cytochrome c1 subunits varied depending on the redox state and substrate. In the absence of quinols, the reduced Rieske domain interacted more closely with cytochrome b and cytochrome c1 than in the oxidized state. Upon addition of the inhibitor antimycin A, the heterogeneity of the cd1-helix and ef-loop increased, which may be indicative of a long-range effect on the Rieske domain.
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Affiliation(s)
- Jan-Philip Wieferig
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
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6
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Li X, Zhou D, Yang D, Fu Y, Tao X, Hu X, Dai Y, Yue H. Isoquercitrin Attenuates Osteogenic Injury in MC3T3 Osteoblastic Cells and the Zebrafish Model via the Keap1-Nrf2-ARE Pathway. Molecules 2022; 27:molecules27113459. [PMID: 35684398 PMCID: PMC9182080 DOI: 10.3390/molecules27113459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/21/2022] [Accepted: 05/26/2022] [Indexed: 11/24/2022] Open
Abstract
Isoquercitrin (IQ) widely exists in natural products, with a variety of pharmacological activities. In this study, the anti-apoptotic and antioxidative activities of IQ were evaluated. IQ showed protective activity against 2, 2′-azobis [2-methylpropionamidine] dihydrochloride (AAPH)-induced cell damage, as well as a marked reduction in reactive oxygen species (ROS). The evidence of IQ regulating Keap1-Nrf2-ARE and the mitochondrial-mediated Caspase 3 pathway were found in the MC3T3 osteoblastic cell line. Furthermore, IQ significantly decreased ROS production, apoptosis, and lipid peroxidation in AAPH-treated 72 h post-fertilization (hpf) zebrafish, as observed via DCFH-DA, acridine orange (AO), and a 1,3-bis(diphenylphosphino) propane (DPPP) probe, respectively. In AAPH-treated 9 day post-fertilization (dpf) zebrafish, IQ strongly promoted osteogenic development, with increased concentrations by calcein staining, compared with the untreated group. In a molecular docking assay, among all signal proteins, Keap1 showed the strongest affinity with IQ at −8.6 kcal/mol, which might be the reason why IQ regulated the Keap1-Nrf2-ARE pathway in vitro and in vivo. These results indicated that IQ promotes bone development and repairs bone injury, which is valuable for the prevention and treatment of bone diseases.
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Affiliation(s)
| | | | | | | | | | | | - Yulin Dai
- Correspondence: (Y.D.); (H.Y.); Tel.: +86-431-8676-3986 (H.Y.); Fax: +86-431-8676-3986 (H.Y.)
| | - Hao Yue
- Correspondence: (Y.D.); (H.Y.); Tel.: +86-431-8676-3986 (H.Y.); Fax: +86-431-8676-3986 (H.Y.)
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7
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Liu J, Ma L, Zhang G, Chen Y, Wang Z. Recent Progress of Surface Modified Nanomaterials for Scavenging Reactive Oxygen Species in Organism. Bioconjug Chem 2021; 32:2269-2289. [PMID: 34669378 DOI: 10.1021/acs.bioconjchem.1c00402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reactive oxygen species (ROS) are essential for normal physiological processes and play important roles in signal transduction, immunity, and tissue homeostasis. However, excess ROS may have a negative effect on the normal cells leading to various diseases. Nanomaterials are an attractive therapeutic alternative of antioxidants and possess an intrinsic ability to scavenge ROS. Surface modification for nanomaterials is a critical strategy to improve their comprehensive performances. Herein, we review the different surface modified strategies for nanomaterials to scavenge ROS and their inherent antioxidant capability, mechanisms of action, and biological applications. At last, the primary challenges and future perspectives in this emerging research frontier have also been highlighted. It is believed that this review paper will offer a top understanding and guidance on engineering future high-performance surface modified ROS scavenging nanomaterials for wide biomedical applications.
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Affiliation(s)
- Jiang Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Lijun Ma
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Guoyang Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Yuzhi Chen
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
- Institute of Health Service and Transfusion Medicine, Academy of Military Medical Sciences, Beijing 100039, P. R. China
| | - Zhuo Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
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8
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Treberg JR. Review: Using isolated mitochondria to investigate mitochondrial hydrogen peroxide metabolism. Comp Biochem Physiol B Biochem Mol Biol 2021; 256:110614. [PMID: 33965616 DOI: 10.1016/j.cbpb.2021.110614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/20/2021] [Accepted: 05/04/2021] [Indexed: 12/13/2022]
Abstract
Mitochondria are recognized as centrally important to cellular reactive oxygen species (ROS), both as a potential source and due to their substantial antioxidant capacity. While much of the initial ROS formed by mitochondria is superoxide, this is rapidly converted to hydrogen peroxide (H2O2) which more readily crosses membranes making H2O2 important in both redox signalling mechanisms and conditions of oxidative stress. Here I outline our studies on mitochondrial H2O2 metabolism with a focus on some of the challenges and strategies involved with developing an integrated model of mitochondria being intrinsic regulators of H2O2. This view of mitochondria as regulators of H2O2 goes beyond the simpler contention of them being net producers or consumers. Moreover, the integration of both consumption and production can then be tied to a putative mechanism linking energy sensing at the level of the mitochondrial protonmotive force. This mechanism would provide a means of mitochondria communicating their energetic status the extramitochondrial compartment via local H2O2 concentrations. I conclude by explaining how these concepts developed using rodent muscle as a model have high relevance and applicability to comparative studies.
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Affiliation(s)
- Jason R Treberg
- Department of Biological Sciences, University of Manitoba Winnipeg, MB R3T 2N2, Canada.
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9
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Sarewicz M, Pintscher S, Bujnowicz Ł, Wolska M, Artur Osyczka. The High-Spin Heme b L Mutant Exposes Dominant Reaction Leading to the Formation of the Semiquinone Spin-Coupled to the [2Fe-2S] + Cluster at the Q o Site of Rhodobacter capsulatus Cytochrome bc 1. Front Chem 2021; 9:658877. [PMID: 34026724 PMCID: PMC8138165 DOI: 10.3389/fchem.2021.658877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Cytochrome bc 1 (mitochondrial complex III) catalyzes electron transfer from quinols to cytochrome c and couples this reaction with proton translocation across lipid membrane; thus, it contributes to the generation of protonmotive force used for the synthesis of ATP. The energetic efficiency of the enzyme relies on a bifurcation reaction taking place at the Qo site which upon oxidation of ubiquinol directs one electron to the Rieske 2Fe2S cluster and the other to heme b L. The molecular mechanism of this reaction remains unclear. A semiquinone spin-coupled to the reduced 2Fe2S cluster (SQo-2Fe2S) was identified as a state associated with the operation of the Qo site. To get insights into the mechanism of the formation of this state, we first constructed a mutant in which one of the histidine ligands of the iron ion of heme b L Rhodobacter capsulatus cytochrome bc 1 was replaced by asparagine (H198N). This converted the low-spin, low-potential heme into the high-spin, high-potential species which is unable to support enzymatic turnover. We performed a comparative analysis of redox titrations of antimycin-supplemented bacterial photosynthetic membranes containing native enzyme and the mutant. The titrations revealed that H198N failed to generate detectable amounts of SQo-2Fe2S under neither equilibrium (in dark) nor nonequilibrium (in light), whereas the native enzyme generated clearly detectable SQo-2Fe2S in light. This provided further support for the mechanism in which the back electron transfer from heme b L to a ubiquinone bound at the Qo site is mainly responsible for the formation of semiquinone trapped in the SQo-2Fe2S state in R. capusulatus cytochrome bc 1.
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Affiliation(s)
- Marcin Sarewicz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Sebastian Pintscher
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Łukasz Bujnowicz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Małgorzata Wolska
- 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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10
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Redox Active Antimicrobial Peptides in Controlling Growth of Microorganisms at Body Barriers. Antioxidants (Basel) 2021; 10:antiox10030446. [PMID: 33805777 PMCID: PMC7998263 DOI: 10.3390/antiox10030446] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 01/14/2023] Open
Abstract
Epithelia in the skin, gut and other environmentally exposed organs display a variety of mechanisms to control microbial communities and limit potential pathogenic microbial invasion. Naturally occurring antimicrobial proteins/peptides and their synthetic derivatives (here collectively referred to as AMPs) reinforce the antimicrobial barrier function of epithelial cells. Understanding how these AMPs are functionally regulated may be important for new therapeutic approaches to combat microbial infections. Some AMPs are subject to redox-dependent regulation. This review aims to: (i) explore cysteine-based redox active AMPs in skin and intestine; (ii) discuss casual links between various redox environments of these barrier tissues and the ability of AMPs to control cutaneous and intestinal microbes; (iii) highlight how bacteria, through intrinsic mechanisms, can influence the bactericidal potential of redox-sensitive AMPs.
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11
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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: 61] [Impact Index Per Article: 20.3] [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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