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Sharma S, Sandhir R, Ganju L, Kumar B, Singh Y. Unique mutations in mitochondrial DNA and associated pathways involved in high altitude pulmonary edema susceptibility in Indian lowlanders. J Biomol Struct Dyn 2022:1-16. [PMID: 35666092 DOI: 10.1080/07391102.2022.2081610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
High altitude pulmonary edema (HAPE) is a life threatening non-cardiogenic pulmonary edema that occurs in an otherwise healthy individuals travelling to altitude above 2500 m. Earlier studies have reported association of mutations in nuclear (nDNA) and mitochondrial DNA (mtDNA) with HAPE susceptibility. However, the molecular mechanisms involved in the pathobiology of HAPE have not been fully understood. The present study investigates the genetic predisposition to HAPE by analyzing the mtDNA mutations in HAPE susceptibles (n = 23) and acclimatized controls (n = 23) using next generation sequencing. Structural analysis of mutations was done using SWISS Model server and stability was determined using ΔΔG values. Meta-analysis of GSE52209 dataset was done to identify differentially expressed genes (DEGs) in HAPE susceptibles and acclimatized controls. Fourteen non-synonymous, conserved and pathogenic mutations were predicted using SIFT and PolyPhen scoring in protein coding genes, whereas six mutations in mt-tRNA genes showed association with HAPE (p ≤ 0.05). The structural analysis of these mutations revealed conformational changes in critical regions in Complexes I-V which are involved in subunit assembly and proton pumping activity. The protein-protein interaction network analysis of DEGs showed that HIF1α, EGLN2, EGLN3, PDK1, TFAM, PPARGC1α and NRF1 genes form highly interconnected cluster. Further, pathway enrichment analysis using DAVID revealed that "HIF-1 signaling", "oxidative phosphorylation" and "Metabolic pathways" had strong association with HAPE. Based on the findings it appears that the identified mtDNA mutations may be a potential risk factor in development of HAPE with the associated pathways providing mechanistic insight into the understanding of pathobiology of HAPE and sites for development of therapeutic targets.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Swati Sharma
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Timarpur, Delhi, India.,Department of Biochemistry, Basic Medical Sciences Block II, Panjab University, Chandigarh, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Sciences Block II, Panjab University, Chandigarh, India
| | - Lilly Ganju
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Timarpur, Delhi, India
| | - Bhuvnesh Kumar
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Timarpur, Delhi, India
| | - Yamini Singh
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Timarpur, Delhi, India
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2
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Gao W, Zhang J, Wang W, Liu Z, Chen M, Hu X, Zeng L, Zheng C, Song H, Zhang Q. Drug Self-delivery Nanorods Enhance Photodynamic Therapy of Triple-Negative Breast Cancer by inhibiting Oxidative Phosphorylation. Int J Pharm 2022; 621:121775. [PMID: 35489603 DOI: 10.1016/j.ijpharm.2022.121775] [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: 01/05/2022] [Revised: 04/08/2022] [Accepted: 04/23/2022] [Indexed: 11/26/2022]
Abstract
Photodynamic therapy (PDT) shows very high potential for the clinical treatment of triple-negative breast cancer. However, the efficacy of PDT is significantly weakened by tumor hypoxia, the relatively high intracellular glutathione levels and the active proliferation of cancer cells. To address these issues, we developed a novel drug self-delivery nanorod (defined as AINRs) through the hydrophobic interaction among the mitochondrial complex III inhibitor (atovaquone, ATO), the photosensitizer (indocyanine green, ICG) and the dispersion stabilizer (distearoyl phosphoethanolamine-polyethylene glycol 2000, DSPE-PEG 2000). The AINRs showed a rod-like morphology with a mean diameter of 120.6 ± 5.4 nm, a zeta potential of -26.35 ± 1.63 mV and a significantly high drug loading rate of 93.48%. The results of in vitro cell experiments involving triple-negative breast cancer cell lines (4T1 cells and MDA-MB-231 cells) indicated that the AINRs could effectively block the oxidative phosphorylation of cancer cells through the inhibition of mitochondrial complex III, which results in the reduction of endogenous oxygen consumption and the decrease of the intracellular ATP level. The reduction of ATP content further inhibited the glutathione synthesis and arrested the cell cycle at the S-phase, which results in enhanced in vitro PDT efficacy of ICG. The results of in vivo antitumor activity in 4T1-bearing mice showed that the tumor growth inhibition rate of the AINRs with near-infrared laser irradiation (NIR) was 90%, whereas the tumor growth inhibition rates of the AINRs without NIR, ICG with NIR and doxorubicin (3 mg/kg) were only 31.68%, 61.15% and 24.59%, respectively. In addition, the results of safety studies, including body weights, biochemical indicators and H&E staining images of the main organs demonstrated the security of the AINRs. In summary, this study showed that the oxidative phosphorylation inhibition of triple-negative breast cancer was a safe and effective method to enhance its PDT efficacy.
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Affiliation(s)
- Wenhao Gao
- College of Pharmacy, Fujian Medical University, Fuzhou 350122, PR China; Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Jialiang Zhang
- Innovation center for cancer research, Fujian Medical University Cancer Hospital, Fujian Cancer Hospital, Fuzhou 350014, PR China
| | - Weifeng Wang
- College of Pharmacy, Fujian Medical University, Fuzhou 350122, PR China; Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Zhihong Liu
- Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Mulan Chen
- Department of Breast Cancer, Fujian Medical University Cancer Hospital, Fujian Cancer Hospital, Fuzhou 350014, PR China
| | - Xiaomu Hu
- Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Lingjun Zeng
- Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Changqing Zheng
- Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China
| | - Hongtao Song
- College of Pharmacy, Fujian Medical University, Fuzhou 350122, PR China; Department of Pharmacy, Fuzong Clinical Medical College of Fujian Medical University (900 Hospital of the Joint Logistics Team), Fuzhou 350025, PR China.
| | - Qian Zhang
- College of Pharmacy, Fujian Medical University, Fuzhou 350122, PR China.
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3
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Yang B, Ding M, Chen Y, Han F, Yang C, Zhao J, Malard P, Stanton C, Ross RP, Zhang H, Chen W. Development of gut microbiota and bifidobacterial communities of neonates in the first 6 weeks and their inheritance from mother. Gut Microbes 2022; 13:1-13. [PMID: 33847206 PMCID: PMC8049200 DOI: 10.1080/19490976.2021.1908100] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Microbiota especially Bifidobacterium play an important role in adjusting and maintaining homeostatic balance within the infant intestine. The aim of this study was to elucidate the relationship between maternal and infant gut microbiota and identify the Bifidobacterium species that may transfer from mother to infant over the first 42 days of the infant's life. Nineteen mother-infant-pair fecal samples were collected and the diversity and composition of the total bacterial and Bifidobacterium communities were analyzed via 16S rDNA and bifidobacterial groEL gene high throughput sequencing. The results revealed that the relative abundance of Bifidobacterium was significantly higher in the infant gut while Parabacteroides, Blautia, Coprococcus, Lachnospira and Faecalibacterium were at lower relative abundance in 7-day and 42-day infant fecal samples compared to the maternal samples. The maternal gut has more B. pseudocatenulatum. In the infant group, B. breve and B. dentium relative abundance increased while B. animalis subsp. lactis decreased from days 7 to 42. Additionally, B. longum subsp. longum isolated from FGZ16 and FGZ35 may have transferred from mother to infant and colonized the infant gut. The results of the current study provide insight toward the infant gut microbiota composition and structure during the first 42 days and may help guide Bifidobacterium supplementation strategies in mothers and infants.
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Affiliation(s)
- Bo Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China,International Joint Research Laboratory for Pharmabiotics & Antibiotic Resistance, Jiangnan University, Wuxi, China
| | - Mengfan Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Yingqi Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Fengzhen Han
- Department of Gynaecology and Obsterics, Guangdong Province People’s Hospital, Guangdong Academy of Medical Science, Guangzhou, China
| | - Chunyan Yang
- Department of Gynaecology and Obsterics, Guangdong Province People’s Hospital, Guangdong Academy of Medical Science, Guangzhou, China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China
| | - Patrice Malard
- Biostime (Guangzhou) Health Products Ltd., Guangzhou, China
| | - Catherine Stanton
- International Joint Research Laboratory for Pharmabiotics & Antibiotic Resistance, Jiangnan University, Wuxi, China,Food Bioscience, Teagasc Food Research Centre, Fermoy, Ireland,CONTACT Catherine Stanton Teagasc Food Research Centre, Fermoy, Ireland
| | - R. Paul Ross
- International Joint Research Laboratory for Pharmabiotics & Antibiotic Resistance, Jiangnan University, Wuxi, China,APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China,Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China,School of Food Science and Technology, Jiangnan University, Wuxi, China,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China,Wei Chen School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
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4
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Sindhu T, Debnath P. Cytochrome bc1-aa3 oxidase supercomplex as emerging and potential drug target against tuberculosis. Curr Mol Pharmacol 2021; 15:380-392. [PMID: 34602044 DOI: 10.2174/1874467214666210928152512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/26/2021] [Accepted: 06/06/2021] [Indexed: 11/22/2022]
Abstract
The cytochrome bc1-aa3 supercomplex plays an essential role in the cellular respiratory system of Mycobacterium Tuberculosis. It transfers electrons from menaquinol to cytochrome aa3 (Complex IV) via cytochrome bc1 (Complex III), which reduces the oxygen. The electron transfer from a variety of donors into oxygen through the respiratory electron transport chain is essential to pump protons across the membrane creating an electrochemical transmembrane gradient (proton motive force, PMF) that regulates the synthesis of ATP via the oxidative phosphorylation process. Cytochrome bc1-aa3 supercomplex in M. tuberculosis is, therefore, a major drug target for antibiotic action. In recent years, several respiratory chain components have been targeted for developing new candidate drugs, illustrating the therapeutic potential of obstructing energy conversion of M. tuberculosis. The recently available cryo-EM structure of mycobacterial cytochrome bc1-aa3 supercomplex with open and closed conformations has opened new avenues for understanding its structure and function for developing more effective, new therapeutics against pulmonary tuberculosis. In this review, we discuss the role and function of several components, subunits, and drug targeting elements of the supercomplex cytochrome bc1-aa3, and its potential inhibitors in detail.
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Affiliation(s)
- Thangaraj Sindhu
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
| | - Pal Debnath
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
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5
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Lin CH, Tsai PI, Lin HY, Hattori N, Funayama M, Jeon B, Sato K, Abe K, Mukai Y, Takahashi Y, Li Y, Nishioka K, Yoshino H, Daida K, Chen ML, Cheng J, Huang CY, Tzeng SR, Wu YS, Lai HJ, Tsai HH, Yen RF, Lee NC, Lo WC, Hung YC, Chan CC, Ke YC, Chao CC, Hsieh ST, Farrer M, Wu RM. Mitochondrial UQCRC1 mutations cause autosomal dominant parkinsonism with polyneuropathy. Brain 2021; 143:3352-3373. [PMID: 33141179 PMCID: PMC7719032 DOI: 10.1093/brain/awaa279] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/25/2020] [Accepted: 07/12/2020] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease is a neurodegenerative disorder with a multifactorial aetiology. Nevertheless, the genetic predisposition in many families with multi-incidence disease remains unknown. This study aimed to identify novel genes that cause familial Parkinson's disease. Whole exome sequencing was performed in three affected members of the index family with a late-onset autosomal-dominant parkinsonism and polyneuropathy. We identified a novel heterozygous substitution c.941A>C (p.Tyr314Ser) in the mitochondrial ubiquinol-cytochrome c reductase core protein 1 (UQCRC1) gene, which co-segregates with disease within the family. Additional analysis of 699 unrelated Parkinson's disease probands with autosomal-dominant Parkinson's disease and 1934 patients with sporadic Parkinson's disease revealed another two variants in UQCRC1 in the probands with familial Parkinson's disease, c.931A>C (p.Ile311Leu) and an allele with concomitant splicing mutation (c.70-1G>A) and a frameshift insertion (c.73_74insG, p.Ala25Glyfs*27). All substitutions were absent in 1077 controls and the Taiwan Biobank exome database from healthy participants (n = 1517 exomes). We then assayed the pathogenicity of the identified rare variants using CRISPR/Cas9-based knock-in human dopaminergic SH-SY5Y cell lines, Drosophila and mouse models. Mutant UQCRC1 expression leads to neurite degeneration and mitochondrial respiratory chain dysfunction in SH-SY5Y cells. UQCRC1 p.Tyr314Ser knock-in Drosophila and mouse models exhibit age-dependent locomotor defects, dopaminergic neuronal loss, peripheral neuropathy, impaired respiratory chain complex III activity and aberrant mitochondrial ultrastructures in nigral neurons. Furthermore, intraperitoneal injection of levodopa could significantly improve the motor dysfunction in UQCRC1 p.Tyr314Ser mutant knock-in mice. Taken together, our in vitro and in vivo studies support the functional pathogenicity of rare UQCRC1 variants in familial parkinsonism. Our findings expand an additional link of mitochondrial complex III dysfunction in Parkinson's disease.
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Affiliation(s)
- Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-I Tsai
- Department of Biochemistry and Biophysics, University of California San Francisco, USA
| | - Han-Yi Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Manabu Funayama
- Research Institute for Diseases of Old Age, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Beomseok Jeon
- Department of Neurology, Movement Disorder Center, Seoul National University Hospital, Parkinson Study Group, Seoul National University College of Medicine, Seoul, Korea
| | - Kota Sato
- Department of Neurology, Okayama University Medical School, Okayama, Japan
| | - Koji Abe
- Department of Neurology, Okayama University Medical School, Okayama, Japan
| | - Yohei Mukai
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Yuanzhe Li
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kenya Nishioka
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiroyo Yoshino
- Research Institute for Diseases of Old Age, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Kensuke Daida
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Meng-Ling Chen
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jay Cheng
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Cheng-Yen Huang
- The first core laboratory, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shiou-Ru Tzeng
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yen-Sheng Wu
- Electron Microscope Laboratory of Tzong Jwo Jang, College of Medicine, Fu Jen Catholic University, Taipei, Taiwan
| | - Hsing-Jung Lai
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsin-Hsi Tsai
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ruoh-Fang Yen
- Department of Nuclear Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wen-Chun Lo
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Chien Hung
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Chiang Chan
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Ci Ke
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chi-Chao Chao
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sung-Tsang Hsieh
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Matthew Farrer
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.,Center for Applied Neurogenetics, University of British Columbia, Canada
| | - Ruey-Meei Wu
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
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6
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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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7
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Pagacz J, Broniec A, Wolska M, Osyczka A, Borek A. ROS signaling capacity of cytochrome bc 1: Opposing effects of adaptive and pathogenic mitochondrial mutations. Free Radic Biol Med 2021; 163:243-254. [PMID: 33352219 DOI: 10.1016/j.freeradbiomed.2020.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/07/2020] [Accepted: 12/12/2020] [Indexed: 01/06/2023]
Abstract
Cytochrome bc1, also known as mitochondrial complex III, is considered to be one of the important producers of reactive oxygen species (ROS) in living organisms. Under physiological conditions, a certain level of ROS produced by mitochondrial electron transport chain (ETC) might be beneficial and take part in cellular signaling. However, elevated levels of ROS might exhibit negative effects, resulting in cellular damage. It is well known that inhibiting the electron flow within mitochondrial complex III leads to high production of ROS. However, superoxide production by cytochrome bc1 in a non-inhibited system remained controversial. Here, we propose a novel method for ROS detection in ETC hybrid system in solution comprising bacterial cytochrome bc1 and mitochondrial complex IV. We clearly show that non-inhibited cytochrome bc1 generates ROS and that adaptive and pathogenic mitochondrial mutations suppress and enhance ROS production, respectively. We also noted that cytochrome bc1 produces ROS in a rate-dependent manner and that the mechanism of ROS generation changes according to the rate of operation of the enzyme. This dependency has not yet been reported, but seems to be crucial when discussing ROS signaling originating from mitochondria.
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Affiliation(s)
- Jakub Pagacz
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Agnieszka Broniec
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Małgorzata Wolska
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Artur Osyczka
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Arkadiusz Borek
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
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8
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Coates JTT, Rodriguez-Berriguete G, Puliyadi R, Ashton T, Prevo R, Wing A, Granata G, Pirovano G, McKenna GW, Higgins GS. The anti-malarial drug atovaquone potentiates platinum-mediated cancer cell death by increasing oxidative stress. Cell Death Discov 2020; 6:110. [PMID: 33133645 PMCID: PMC7591508 DOI: 10.1038/s41420-020-00343-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023] Open
Abstract
Platinum chemotherapies are highly effective cytotoxic agents but often induce resistance when used as monotherapies. Combinatorial strategies limit this risk and provide effective treatment options for many cancers. Here, we repurpose atovaquone (ATQ), a well-tolerated & FDA-approved anti-malarial agent by demonstrating that it potentiates cancer cell death of a subset of platinums. We show that ATQ in combination with carboplatin or cisplatin induces striking and repeatable concentration- and time-dependent cell death sensitization in vitro across a variety of cancer cell lines. ATQ induces mitochondrial reactive oxygen species (mROS), depleting intracellular glutathione (GSH) pools in a concentration-dependent manner. The superoxide dismutase mimetic MnTBAP rescues ATQ-induced mROS production and pre-loading cells with the GSH prodrug N-acetyl cysteine (NAC) abrogates the sensitization. Together, these findings implicate ATQ-induced oxidative stress as key mediator of the sensitizing effect. At physiologically achievable concentrations, ATQ and carboplatin furthermore synergistically delay the growth of three-dimensional avascular spheroids. Clinically, ATQ is a safe and specific inhibitor of the electron transport chain (ETC) and is concurrently being repurposed as a candidate tumor hypoxia modifier. Together, these findings suggest that ATQ is deserving of further study as a candidate platinum sensitizing agent.
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Affiliation(s)
| | | | - Rathi Puliyadi
- Department of Oncology, University of Oxford, Oxford, UK
| | - Thomas Ashton
- Department of Oncology, University of Oxford, Oxford, UK
| | - Remko Prevo
- Department of Oncology, University of Oxford, Oxford, UK
| | - Archie Wing
- Department of Oncology, University of Oxford, Oxford, UK
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9
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Kim K, Yang JO, Sung JY, Lee JY, Park JS, Lee HS, Lee BH, Ren Y, Lee DW, Lee SE. Minimization of energy transduction confers resistance to phosphine in the rice weevil, Sitophilus oryzae. Sci Rep 2019; 9:14605. [PMID: 31601880 PMCID: PMC6787191 DOI: 10.1038/s41598-019-50972-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 09/10/2019] [Indexed: 11/09/2022] Open
Abstract
Infestation of phosphine (PH3) resistant insects threatens global grain reserves. PH3 fumigation controls rice weevil (Sitophilus oryzae) but not highly resistant insect pests. Here, we investigated naturally occurring strains of S. oryzae that were moderately resistant (MR), strongly resistant (SR), or susceptible (wild-type; WT) to PH3 using global proteome analysis and mitochondrial DNA sequencing. Both PH3 resistant (PH3-R) strains exhibited higher susceptibility to ethyl formate-mediated inhibition of cytochrome c oxidase than the WT strain, whereas the disinfectant PH3 concentration time of the SR strain was much longer than that of the MR strain. Unlike the MR strain, which showed altered expression levels of genes encoding metabolic enzymes involved in catabolic pathways that minimize metabolic burden, the SR strain showed changes in the mitochondrial respiratory chain. Our results suggest that the acquisition of strong PH3 resistance necessitates the avoidance of oxidative phosphorylation through the accumulation of a few non-synonymous mutations in mitochondrial genes encoding complex I subunits as well as nuclear genes encoding dihydrolipoamide dehydrogenase, concomitant with metabolic reprogramming, a recognized hallmark of cancer metabolism. Taken together, our data suggest that reprogrammed metabolism represents a survival strategy of SR insect pests for the compensation of minimized energy transduction under anoxic conditions. Therefore, understanding the resistance mechanism of PH3-R strains will support the development of new strategies to control insect pests.
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Affiliation(s)
- Kyeongnam Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Korea
| | - Jeong Oh Yang
- Animal and Plant Quarantine Agency (APQA), Gimcheon, 39660, Korea
| | - Jae-Yoon Sung
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Ji-Young Lee
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea
| | - Jeong Sun Park
- Animal and Plant Quarantine Agency (APQA), Gimcheon, 39660, Korea
| | - Heung-Sik Lee
- Animal and Plant Quarantine Agency (APQA), Gimcheon, 39660, Korea
| | - Byung-Ho Lee
- Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, 52828, Korea
| | - Yonglin Ren
- School of Veterinary and Life Science, Murdoch University, 90 South St., Murdoch, WA, 6150, Australia
| | - Dong-Woo Lee
- Department of Biotechnology, Yonsei University, Seoul, 03722, Korea.
| | - Sung-Eun Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Korea.
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10
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Liu X, Du H, Chen D, Yuan H, Chen W, Jia W, Wang X, Li X, Gao L. Cyclophilin D deficiency protects against the development of mitochondrial ROS and cellular inflammation in aorta. Biochem Biophys Res Commun 2019; 508:1202-1208. [PMID: 30554656 DOI: 10.1016/j.bbrc.2018.12.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Inflammation and oxidative stress are closely correlated in the pathology of cardiovascular disease. Mitochondrial cyclophilin D (CypD), the important modulator for mPTP opening, is increasingly recognized as a key regulator of cellular ROS generation. Besides, its association with cell inflammation is also being discovered. However, the effects of CypD in modulating vascular inflammatory response is unknown. We sought to investigate whether CypD deficiency attenutes vascular inflammation under physical conditions. METHODS AND RESULTS We adopted CypD KO mouse and their littermate controls to observe the effects of CypD deficiency on aortic mitochondrial functions and vascular inflammation. As we found in our study, we confirmed that under physical conditions, CypD deficiency enhanced mouse whole body metabolic status, increased aortic mitochondrial complex III activity and decreased mitochondrial ROS generation. Functionally, CypD deficiency also attenuated inflammatory molecules expression, including VCAM-1, IL-6 and TNF-α in mouse aorta. CONCLUSIONS Our results review that mitochondrial CypD is involved in the regulation of inflammation in aorta and provide insights that blocking mitochondrial CypD enhances vascular resistance to inflammatory injuries.
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Affiliation(s)
- Xiaojing Liu
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China
| | - Heng Du
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Dan Chen
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China; Department of Electrocardiographic, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China
| | - Hai Yuan
- Department of Vascular Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China
| | - Wenbin Chen
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China
| | - Wenyu Jia
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China
| | - Xiaolei Wang
- Deparment of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, 250021, China; Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China
| | - Xia Li
- Department of Ultrasound, Shandong Provincial Hospital Affiliated to Shandong University, Shandong University, Jinan, Shandong, 250021, China.
| | - Ling Gao
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China; Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, 250021, China.
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11
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Francia F, Khalfaoui-Hassani B, Lanciano P, Musiani F, Noodleman L, Venturoli G, Daldal F. The cytochrome b lysine 329 residue is critical for ubihydroquinone oxidation and proton release at the Q o site of bacterial cytochrome bc 1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:167-179. [PMID: 30550726 DOI: 10.1016/j.bbabio.2018.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 11/16/2022]
Abstract
The ubihydroquinone:cytochrome (cyt) c oxidoreductase (or cyt bc1) is an important enzyme for photosynthesis and respiration. In bacteria like Rhodobacter capsulatus, this membrane complex has three subunits, the iron‑sulfur protein (ISP) with its Fe2S2 cluster, cyt c1 and cyt b, forming two catalytic domains, the Qo (hydroquinone (QH2) oxidation) and Qi (quinone (Q) reduction) sites. At the Qo site, the electron transfer pathways originating from QH2 oxidation are known, but their associated proton release routes are less well defined. Earlier, we demonstrated that the His291 of cyt b is important for this latter process. In this work, using the bacterial cyt bc1 and site directed mutagenesis, we show that Lys329 of cyt b is also critical for electron and proton transfer at the Qo site. Of the mutants examined, Lys329Arg was photosynthesis proficient and had quasi-wild type cyt bc1 activity. In contrast, the Lys329Ala and Lys329Asp were photosynthesis-impaired and contained defective but assembled cyt bc1. In particular, the bifurcated electron transfer and associated proton(s) release reactions occurring during QH2 oxidation were drastically impaired in Lys329Asp mutant. Furthermore, in silico docking studies showed that in this mutant the location and the H-bonding network around the Fe2S2 cluster of ISP on cyt b surface was different than the wild type enzyme. Based on these experimental findings and theoretical considerations, we propose that the presence of a positive charge at position 329 of cyt b is critical for efficient electron transfer and proton release for QH2 oxidation at the Qo site of cyt bc1.
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Affiliation(s)
- Francesco Francia
- Dipartimento di Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy
| | | | - Pascal Lanciano
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Francesco Musiani
- Dipartimento di Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy
| | - Louis Noodleman
- The Scripps Research Institute, Department of Integrative Structural and Computational Biology, La Jolla, CA 92037, USA
| | - Giovanni Venturoli
- Dipartimento di Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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12
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Turroni F, Milani C, Duranti S, Ferrario C, Lugli GA, Mancabelli L, van Sinderen D, Ventura M. Bifidobacteria and the infant gut: an example of co-evolution and natural selection. Cell Mol Life Sci 2018; 75:103-118. [PMID: 28983638 PMCID: PMC11105234 DOI: 10.1007/s00018-017-2672-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 09/29/2017] [Indexed: 12/16/2022]
Abstract
Throughout the human life, the gut microbiota interacts with us in a number of different ways, thereby influencing our health status. The acquisition of such an interactive gut microbiota commences at birth. Medical and environmental factors including diet, antibiotic exposure and mode of delivery are major factors that shape the composition of the microbial communities in the infant gut. Among the most abundant members of the infant microbiota are species belonging to the Bifidobacterium genus, which are believed to confer beneficial effects upon their host. Bifidobacteria may be acquired directly from the mother by vertical transmission and their persistence in the infant gut is associated with their saccharolytic activity toward glycans that are abundant in the infant gut. Here, we discuss the establishment of the infant gut microbiota and the contribution of bifidobacteria to this early life microbial consortium.
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Affiliation(s)
- Francesca Turroni
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
- Microbiome Research Hub, University of Parma, Parma, Italy
| | - Christian Milani
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Sabrina Duranti
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Chiara Ferrario
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Gabriele Andrea Lugli
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Leonardo Mancabelli
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Douwe van Sinderen
- APC Microbiome Institute and School of Microbiology, National University of Ireland, Cork, Ireland
| | - Marco Ventura
- Laboratory of Probiogenomics, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy.
- Microbiome Research Hub, University of Parma, Parma, Italy.
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13
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Husen P, Solov'yov IA. Mutations at the Q o Site of the Cytochrome bc 1 Complex Strongly Affect Oxygen Binding. J Phys Chem B 2016; 121:3308-3317. [PMID: 27748117 DOI: 10.1021/acs.jpcb.6b08226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The homodimeric bc1 protein complex is embedded in membranes of mitochondria and photosynthetic bacteria, where it transports protons across the membrane to maintain an electrostatic potential used to drive ATP synthesis as part of the respiratory or photosynthetic pathways. The reaction cycle of the bc1 complex is driven by series of redox processes involving substrate molecules from the membrane, but occasional side reactions between an intermediate semiquinone substrate and molecular oxygen are suspected to be a source of toxic superoxide, which is believed to be a factor in aging. The present investigation employs molecular dynamics simulations to study the effect of mutations in the Qo binding sites of the bc1 complex on the ability of oxygen molecules to migrate to and bind at various locations within the complex. It is found that the mutations strongly affect the ability of oxygen to bind at the Qo sites, and moreover, different behavior of the two monomers of the bc1 complex is observed. The conformational differences at the Qo sites of the two monomers are studied in detail and discussed. The anionic form of semiquinone was identified as leading to the greatest opportunity for side reactions with oxygen.
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Affiliation(s)
- Peter Husen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Ilia A Solov'yov
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
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14
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Ko Y, Choi I. Putative 3D Structure of QcrB fromMycobacterium tuberculosisCytochromebc1 Complex, a Novel Drug-Target for New Series of Antituberculosis Agent Q203. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10765] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yoonae Ko
- Cheminformatics Group; Institut Pasteur Korea; Gyeonggi-do 13488 Republic of Korea
| | - Inhee Choi
- Cheminformatics Group; Institut Pasteur Korea; Gyeonggi-do 13488 Republic of Korea
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15
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Ekiert R, Borek A, Kuleta P, Czernek J, Osyczka A. Mitochondrial disease-related mutations at the cytochrome b-iron-sulfur protein (ISP) interface: Molecular effects on the large-scale motion of ISP and superoxide generation studied in Rhodobacter capsulatus cytochrome bc1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1102-1110. [PMID: 27032290 PMCID: PMC4906154 DOI: 10.1016/j.bbabio.2016.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 01/06/2023]
Abstract
One of the important elements of operation of cytochrome bc1 (mitochondrial respiratory complex III) is a large scale movement of the head domain of iron–sulfur protein (ISP-HD), which connects the quinol oxidation site (Qo) located within the cytochrome b, with the outermost heme c1 of cytochrome c1. Several mitochondrial disease-related mutations in cytochrome b are located at the cytochrome b-ISP-HD interface, thus their molecular effects can be associated with altered motion of ISP-HD. Using purple bacterial model, we recently showed that one of such mutations — G167P shifts the equilibrium position of ISP-HD towards positions remote from the Qo site as compared to the native enzyme [Borek et al., J. Biol. Chem. 290 (2015) 23781-23792]. This resulted in the enhanced propensity of the mutant to generate reactive oxygen species (ROS) which was explained on the basis of the model evoking “semireverse” electron transfer from heme bL to quinone. Here we examine another mutation from that group — G332D (G290D in human), finding that it also shifts the equilibrium position of ISP-HD in the same direction, however displays less of the enhancement in ROS production. We provide spectroscopic indication that G332D might affect the electrostatics of interaction between cytochrome b and ISP-HD. This effect, in light of the measured enzymatic activities and electron transfer rates, appears to be less severe than structural distortion caused by proline in G167P mutant. Comparative analysis of the effects of G332D and G167P confirms a general prediction that mutations located at the cytochrome b-ISP-HD interface influence the motion of ISP-HD and indicates that “pushing” ISP-HD away from the Qo site is the most likely outcome of this influence. It can also be predicted that an increase in ROS production associated with the “pushing” effect is quite sensitive to overall severity of this change with more active mutants being generally more protected against elevated ROS. This article is part of a Special Issue entitled ‘EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2–6, 2016’, edited by Prof. Paolo Bernardi. Several mitochondrial mutations are located at the cytochrome b-ISP interface. We compare molecular effects of two mutations from that group. In both mutants ISP is shifted away from the Qo catalytic site. This effect is generally associated with increased ROS production. More active mutants are more protected against elevated ROS.
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Affiliation(s)
- Robert Ekiert
- 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
| | - Patryk Kuleta
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Justyna Czernek
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Artur Osyczka
- Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
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16
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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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17
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Saccharomyces cerevisiae-based mutational analysis of the bc1 complex Qo site residue 279 to study the trade-off between atovaquone resistance and function. Antimicrob Agents Chemother 2015; 59:4053-8. [PMID: 25918152 DOI: 10.1128/aac.00710-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/19/2015] [Indexed: 11/20/2022] Open
Abstract
The bc1 complex is central to mitochondrial bioenergetics and the target of the antimalarial drug atovaquone that binds in the quinol oxidation (Qo) site of the complex. Structural analysis has shown that the Qo site residue Y279 (Y268 in Plasmodium falciparum) is key for atovaquone binding. Consequently, atovaquone resistance can be acquired by mutation of that residue. In addition to the probability of amino acid substitution, the level of atovaquone resistance and the loss of bc1 complex activity that are associated with the novel amino acid would restrict the nature of resistance-driven mutations occurring on atovaquone exposure in native parasite populations. Using the yeast model, we characterized the effect of all the amino acid replacements resulting from a single nucleotide substitution at codon 279: Y279C, Y279D, Y279F, Y279H, Y279N, and Y279S (Y279C, D, F, H, N, and S). Two residue changes that required a double nucleotide substitution, Y279A and W, were added to the series. We found that mutations Y279A, C, and S conferred high atovaquone resistance but decreased the catalytic activity. Y279F had wild-type enzymatic activity and sensitivity to atovaquone, while the other substitutions caused a dramatic respiratory defect. The results obtained with the yeast model were examined in regard to atomic structure and compared to the reported data on the evolution of acquired atovaquone resistance in P. falciparum.
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18
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Loo JH, Trejaut JA, Yen JC, Chen ZS, Ng WM, Huang CY, Hsu KN, Hung KH, Hsiao Y, Wei YH, Lin M. Mitochondrial DNA association study of type 2 diabetes with or without ischemic stroke in Taiwan. BMC Res Notes 2014; 7:223. [PMID: 24713204 PMCID: PMC4108081 DOI: 10.1186/1756-0500-7-223] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022] Open
Abstract
Background The importance of mitochondrial DNA (mtDNA) polymorphism in the prediction of type 2 diabetes (T2D) in men and women is not well understood. We questioned whether mtDNA polymorphism, mitochondrial functions, age and gender influenced the occurrence of T2D with or without ischemic stroke (IS). Methods We first designed a matched case–control study of 373 T2D patients and 327 healthy unrelated individuals without history of IS. MtDNA haplogroups were determined on all participants using sequencing of the control region and relevant SNPs from the coding region. Mitochondria functional tests, systemic biochemical measurements and complete genomic mtDNA sequencing were further determined on 239 participants (73 healthy controls, 33 T2D with IS, 70 T2D only and 63 IS patients without T2D). Results MtDNA haplogroups B4a1a, and E2b1 showed significant association with T2D (P <0.05), and haplogroup D4 indicated resistance (P <0.05). Mitochondrial and systemic functional tests showed significantly less variance within groups bearing the same mtDNA haplotypes. There was a pronounced male excess among all T2D patients and prevalence of IS was seen only in the older population. Finally, nucleotide variant np 15746, a determinant of haplogroup G3 seen in Japanese and of B4a1a prevalent in Taiwanese was associated with T2D in both populations. Conclusions Men appeared more susceptible to T2D than women. Although the significant association of B4a1a and E2b1 with T2D ceased when corrected for multiple testings, these haplogroups are seen only among Taiwan Aborigines, Southeast Asian and the Pacific Ocean islanders where T2D is predominant. The data further suggested that physiological and biochemical measurements were influenced by the mtDNA genetic profile of the individual. More understanding of the function of the mitochondrion in the development of T2D might indicate ways of influencing the early course of the disease.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Marie Lin
- Mackay Memorial Hospital, No, 45, Mínshēng Rd, Danshui District, New Taipei City, Taiwan.
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19
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Esser L, Yu CA, Xia D. Structural basis of resistance to anti-cytochrome bc₁ complex inhibitors: implication for drug improvement. Curr Pharm Des 2014; 20:704-24. [PMID: 23688079 PMCID: PMC4788501 DOI: 10.2174/138161282005140214163327] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 05/09/2013] [Indexed: 11/22/2022]
Abstract
The emergence of drug resistance has devastating economic and social consequences, a testimonial of which is the rise and fall of inhibitors against the respiratory component cytochrome bc₁ complex, a time tested and highly effective target for disease control. Unfortunately, the mechanism of resistance is a multivariate problem, including primarily mutations in the gene of the cytochrome b subunit but also activation of alternative pathways of ubiquinol oxidation and pharmacokinetic effects. There is a considerable interest in designing new bc₁ inhibitors with novel modes of binding and lower propensity to induce the development of resistance. The accumulation of crystallographic data of bc₁ complexes with and without inhibitors bound provides the structural basis for rational drug design. In particular, the cytochrome b subunit offers two distinct active sites that can be targeted for inhibition - the quinol oxidation site and the quinone reduction site. This review brings together available structural information of inhibited bc₁ by various quinol oxidation- and reductionsite inhibitors, the inhibitor binding modes, conformational changes upon inhibitor binding of side chains in the active site and large scale domain movements of the iron-sulfur protein subunit. Structural data analysis provides a clear understanding of where and why existing inhibitors fail and points towards promising alternatives.
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Affiliation(s)
| | | | - Di Xia
- Laboratory of Cell Biology, NCI, NIH, 37 Convent Dr., Building 37, Room 2122C, Bethesda MD 20892.
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20
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Crofts AR, Hong S, Wilson C, Burton R, Victoria D, Harrison C, Schulten K. The mechanism of ubihydroquinone oxidation at the Qo-site of the cytochrome bc1 complex. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:1362-77. [PMID: 23396004 PMCID: PMC3995752 DOI: 10.1016/j.bbabio.2013.01.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 12/12/2012] [Accepted: 01/18/2013] [Indexed: 01/04/2023]
Abstract
1. Recent results suggest that the major flux is carried by a monomeric function, not by an intermonomer electron flow. 2. The bifurcated reaction at the Qo-site involves sequential partial processes, - a rate limiting first electron transfer generating a semiquinone (SQ) intermediate, and a rapid second electron transfer in which the SQ is oxidized by the low potential chain. 3. The rate constant for the first step in a strongly endergonic, proton-first-then-electron mechanism, is given by a Marcus-Brønsted treatment in which a rapid electron transfer is convoluted with a weak occupancy of the proton configuration needed for electron transfer. 4. A rapid second electron transfer pulls the overall reaction over. Mutation of Glu-295 of cyt b shows it to be a key player. 5. In more crippled mutants, electron transfer is severely inhibited and the bell-shaped pH dependence of wildtype is replaced by a dependence on a single pK at ~8.5 favoring electron transfer. Loss of a pK ~6.5 is explained by a change in the rate limiting step from the first to the second electron transfer; the pK ~8.5 may reflect dissociation of QH. 6. A rate constant (<10(3)s(-1)) for oxidation of SQ in the distal domain by heme bL has been determined, which precludes mechanisms for normal flux in which SQ is constrained there. 7. Glu-295 catalyzes proton exit through H(+) transfer from QH, and rotational displacement to deliver the H(+) to exit channel(s). This opens a volume into which Q(-) can move closer to the heme to speed electron transfer. 8. A kinetic model accounts well for the observations, but leaves open the question of gating mechanisms. For the first step we suggest a molecular "escapement"; for the second a molecular ballet choreographed through coulombic interactions. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Antony R Crofts
- Center for Biophysics and Computational Biology, University of Illinois, Urbana, IL 61801, USA; Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
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Xia D, Esser L, Tang WK, Zhou F, Zhou Y, Yu L, Yu CA. Structural analysis of cytochrome bc1 complexes: implications to the mechanism of function. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:1278-94. [PMID: 23201476 PMCID: PMC3593749 DOI: 10.1016/j.bbabio.2012.11.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/13/2012] [Accepted: 11/19/2012] [Indexed: 01/18/2023]
Abstract
The cytochrome bc1 complex (bc1) is the mid-segment of the cellular respiratory chain of mitochondria and many aerobic prokaryotic organisms; it is also part of the photosynthetic apparatus of non-oxygenic purple bacteria. The bc1 complex catalyzes the reaction of transferring electrons from the low potential substrate ubiquinol to high potential cytochrome c. Concomitantly, bc1 translocates protons across the membrane, contributing to the proton-motive force essential for a variety of cellular activities such as ATP synthesis. Structural investigations of bc1 have been exceedingly successful, yielding atomic resolution structures of bc1 from various organisms and trapped in different reaction intermediates. These structures have confirmed and unified results of decades of experiments and have contributed to our understanding of the mechanism of bc1 functions as well as its inactivation by respiratory inhibitors. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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22
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Reconstructing the Qo site of Plasmodium falciparum bc 1 complex in the yeast enzyme. PLoS One 2013; 8:e71726. [PMID: 23951230 PMCID: PMC3741170 DOI: 10.1371/journal.pone.0071726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/09/2013] [Indexed: 11/19/2022] Open
Abstract
The bc 1 complex of the mitochondrial respiratory chain is essential for Plasmodium falciparum proliferation, the causative agent of human malaria. Therefore, this enzyme is an attractive target for antimalarials. However, biochemical investigations of the parasite enzyme needed for the study of new drugs are challenging. In order to facilitate the study of new compounds targeting the enzyme, we are modifying the inhibitor binding sites of the yeast Saccharomyces cerevisiae to generate a complex that mimics the P. falciparum enzyme. In this study we focused on its Qo pocket, the site of atovaquone binding which is a leading antimalarial drug used in treatment and causal prophylaxis. We constructed and studied a series of mutants with modified Qo sites where yeast residues have been replaced by P. falciparum equivalents, or, for comparison, by human equivalents. Mitochondria were prepared from the yeast Plasmodium-like and human-like Qo mutants. We measured the bc 1 complex sensitivity to atovaquone, azoxystrobin, a Qo site targeting fungicide active against P. falciparum and RCQ06, a quinolone-derivative inhibitor of P. falciparum bc 1 complex.The data obtained highlighted variations in the Qo site that could explain the differences in inhibitor sensitivity between yeast, plasmodial and human enzymes. We showed that the yeast Plasmodium-like Qo mutants could be useful and easy-to-use tools for the study of that class of antimalarials.
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23
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Berry EA, De Bari H, Huang LS. Unanswered questions about the structure of cytochrome bc1 complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1258-77. [PMID: 23624176 DOI: 10.1016/j.bbabio.2013.04.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/13/2013] [Accepted: 04/16/2013] [Indexed: 11/25/2022]
Abstract
X-ray crystal structures of bc1 complexes obtained over the last 15 years have provided a firm structural basis for our understanding of the complex. For the most part there is good agreement between structures from different species, different crystal forms, and with different inhibitors bound. In this review we focus on some of the remaining unexplained differences, either between the structures themselves or the interpretations of the structural observations. These include the structural basis for the motion of the Rieske iron-sulfur protein in response to inhibitors, a possible conformational change involving tyrosine132 of cytochrome (cyt) b, the presence of cis-peptides at the beginnings of transmembrane helices C, E, and H, the structural insight into the function of the so-called "Core proteins", different modelings of the retained signal peptide, orientation of the low-potential heme b, and chirality of the Met ligand to heme c1. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Edward A Berry
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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24
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Lanciano P, Khalfaoui-Hassani B, Selamoglu N, Ghelli A, Rugolo M, Daldal F. Molecular mechanisms of superoxide production by complex III: a bacterial versus human mitochondrial comparative case study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:1332-9. [PMID: 23542447 DOI: 10.1016/j.bbabio.2013.03.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/14/2013] [Accepted: 03/20/2013] [Indexed: 12/23/2022]
Abstract
In this mini review, we briefly survey the molecular processes that lead to reactive oxygen species (ROS) production by the respiratory complex III (CIII or cytochrome bc1). In particular, we discuss the "forward" and "reverse" electron transfer pathways that lead to superoxide generation at the quinol oxidation (Qo) site of CIII, and the components that affect these reactions. We then describe and compare the properties of a bacterial (Rhodobacter capsulatus) mutant enzyme producing ROS with its mitochondrial (human cybrids) counterpart associated with a disease. The mutation under study is located at a highly conserved tyrosine residue of cytochrome b (Y302C in R. capsulatus and Y278C in human mitochondria) that is at the heart of the quinol oxidation (Qo) site of CIII. Similarities of the major findings of bacterial and human mitochondrial cases, including decreased catalytic activity of CIII, enhanced ROS production and ensuing cellular responses and damages, are remarkable. This case illustrates the usefulness of undertaking parallel and complementary studies using biologically different yet evolutionarily related systems, such as α-proteobacteria and human mitochondria. It progresses our understanding of CIII mechanism of function and ROS production, and underlines the possible importance of supra-molecular organization of bacterial and mitochondrial respiratory chains (i.e., respirasomes) and their potential disease-associated protective roles. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Pascal Lanciano
- University of Pennsylvania, Department of Biology, Philadelphia, PA, USA
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25
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Ghelli A, Tropeano CV, Calvaruso MA, Marchesini A, Iommarini L, Porcelli AM, Zanna C, De Nardo V, Martinuzzi A, Wibrand F, Vissing J, Kurelac I, Gasparre G, Selamoglu N, Daldal F, Rugolo M. The cytochrome b p.278Y>C mutation causative of a multisystem disorder enhances superoxide production and alters supramolecular interactions of respiratory chain complexes. Hum Mol Genet 2013; 22:2141-51. [PMID: 23418307 DOI: 10.1093/hmg/ddt067] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cytochrome b is the only mtDNA-encoded subunit of the mitochondrial complex III (CIII), the functional bottleneck of the respiratory chain. Previously, the human cytochrome b missense mutation m.15579A>G, which substitutes the Tyr 278 with Cys (p.278Y>C), was identified in a patient with severe exercise intolerance and multisystem manifestations. In this study, we characterized the biochemical properties of cybrids carrying this mutation and report that the homoplasmic p.278Y>C mutation caused a dramatic reduction in the CIII activity and in CIII-driven mitochondrial ATP synthesis. However, the CI, CI + CIII and CII + CIII activities and the rate of ATP synthesis driven by the CI or CII substrate were only partially reduced or unaffected. Consistent with these findings, mutated cybrids maintained the mitochondrial membrane potential in the presence of oligomycin, indicating that it originated from the respiratory electron transport chain. The p.278Y>C mutation enhanced superoxide production, as indicated by direct measurements in mitochondria and by the imbalance of glutathione homeostasis in intact cybrids. Remarkably, although the assembly of CI or CIII was not affected, the examination of respiratory supercomplexes revealed that the amounts of CIII dimer and III2IV1 were reduced, whereas those of I1III2IVn slightly increased. We therefore suggest that the deleterious effects of p.278Y>C mutation on cytochrome b are palliated when CIII is assembled into the supercomplexes I1III2IVn, in contrast to when it is found alone. These findings underline the importance of supramolecular interactions between complexes for maintaining a basal respiratory chain activity and shed light to the molecular basis of disease manifestations associated with this mutation.
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Affiliation(s)
- Anna Ghelli
- Dipartimento di Farmacia e Biotecnologie, Universita` di Bologna, Via Irnerio 42, Bologna 40126, Italy
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26
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Lesnefsky EJ, Hoppel CL. Aged rat heart: Modulation of age-related respiratory defects decreases ischemic-reflow injury. Health (London) 2013. [DOI: 10.4236/health.2013.51001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bleier L, Dröse S. Superoxide generation by complex III: from mechanistic rationales to functional consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1320-31. [PMID: 23269318 DOI: 10.1016/j.bbabio.2012.12.002] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/05/2012] [Accepted: 12/12/2012] [Indexed: 01/21/2023]
Abstract
Apart from complex I (NADH:ubiquinone oxidoreductase) the mitochondrial cytochrome bc1 complex (complex III; ubiquinol:cytochrome c oxidoreductase) has been identified as the main producer of superoxide and derived reactive oxygen species (ROS) within the mitochondrial respiratory chain. Mitochondrial ROS are generally linked to oxidative stress, aging and other pathophysiological settings like in neurodegenerative diseases. However, ROS produced at the ubiquinol oxidation center (center P, Qo site) of complex III seem to have additional physiological functions as signaling molecules during cellular processes like the adaptation to hypoxia. The molecular mechanism of superoxide production that is mechanistically linked to the electron bifurcation during ubiquinol oxidation is still a matter of debate. Some insight comes from extensive kinetic studies with mutated complexes from yeast and bacterial cytochrome bc1 complexes. This review is intended to bridge the gap between those mechanistic studies and investigations on complex III ROS in cellular signal transduction and highlights factors that impact superoxide generation. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Lea Bleier
- Molecular Bioenergetics Group, Medical School, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
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28
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Meunier B, Fisher N, Ransac S, Mazat JP, Brasseur G. Respiratory complex III dysfunction in humans and the use of yeast as a model organism to study mitochondrial myopathy and associated diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1346-61. [PMID: 23220121 DOI: 10.1016/j.bbabio.2012.11.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 11/21/2012] [Accepted: 11/28/2012] [Indexed: 11/25/2022]
Abstract
The bc1 complex or complex III is a central component of the aerobic respiratory chain in prokaryotic and eukaryotic organisms. It catalyzes the oxidation of quinols and the reduction of cytochrome c, establishing a proton motive force used to synthesize adenosine triphosphate (ATP) by the F1Fo ATP synthase. In eukaryotes, the complex III is located in the inner mitochondrial membrane. The genes coding for the complex III have a dual origin. While cytochrome b is encoded by the mitochondrial genome, all the other subunits are encoded by the nuclear genome. In this review, we compile an exhaustive list of the known human mutations and associated pathologies found in the mitochondrially-encoded cytochrome b gene as well as the fewer mutations in the nuclear genes coding for the complex III structural subunits and accessory proteins such as BCS1L involved in the assembly of the complex III. Due to the inherent difficulties of studying human biopsy material associated with complex III dysfunction, we also review the work that has been conducted to study the pathologies with the easy to handle eukaryotic microorganism, the yeast Saccharomyces cerevisiae. Phenotypes, biochemical data and possible effects due to the mutations are also discussed in the context of the known three-dimensional structure of the eukaryotic complex III. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- B Meunier
- CNRS, Centre de Génétique Moléculaire, UPR 3404, Gif-sur-Yvette, F-91198, France
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29
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Victoria D, Burton R, Crofts AR. Role of the -PEWY-glutamate in catalysis at the Q(o)-site of the Cyt bc(1) complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:365-86. [PMID: 23123515 DOI: 10.1016/j.bbabio.2012.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/19/2012] [Accepted: 10/23/2012] [Indexed: 01/09/2023]
Abstract
We re-examine the pH dependence of partial processes of ubihydroquinone (QH(2)) turnover in Glu-295 mutants in Rhodobacter sphaeroides to clarify the mechanistic role. In more crippled mutants, the bell-shaped pH profile of wildtype was replaced by dependence on a single pK at ~8.5 favoring electron transfer. Loss of the pK at 6.5 reflects a change in the rate-limiting step from the first to the second electron transfer. Over the range of pH 6-8, no major pH dependence of formation of the initial reaction complex was seen, and the rates of bypass reactions were similar to the wildtype. Occupancy of the Q(o)-site by semiquinone (SQ) was similar in the wildtype and the Glu→Trp mutant. Since heme b(L) is initially oxidized in the latter, the bifurcated reaction can still occur, allowing estimation of an empirical rate constant <10(3)s(-1) for reduction of heme b(L) by SQ from the domain distal from heme b(L), a value 1000-fold smaller than that expected from distance. If the pK ~8.5 in mutant strains is due to deprotonation of the neutral semiquinone, with Q(•-) as electron donor to heme b(L), then in wildtype this low value would preclude mechanisms for normal flux in which semiquinone is constrained to this domain. A kinetic model in which Glu-295 catalyzes H(+) transfer from QH•, and delivery of the H(+) to exit channel(s) by rotational displacement, and facilitates rapid electron transfer from SQ to heme b(L) by allowing Q(•-) to move closer to the heme, accounts well for the observations.
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Affiliation(s)
- Doreen Victoria
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
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30
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Musatov A, Robinson NC. Susceptibility of mitochondrial electron-transport complexes to oxidative damage. Focus on cytochrome c oxidase. Free Radic Res 2012; 46:1313-26. [PMID: 22856385 DOI: 10.3109/10715762.2012.717273] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Reactive oxygen species (ROS) are associated with a number of mitochondrial disorders. These include: ischemia/reperfusion injury, Parkinson's disease, Alzheimer's disease, neurodegenerative diseases, and other age-related degenerative changes. ROS can be generated at numerous sites within the cell, but the mitochondrial electron transport chain is recognized as the major source of intracellular ROS. Two mitochondrial electron-transfer complexes are major sources of ROS: complex I and complex III. Oxidative damage to either of these complexes, or to electron transport complexes that are in close proximity to these ROS sources, e.g., cytochrome c oxidase, would be expected to inhibit electron transport. Such inhibition would lead to increased electron leakage and more ROS production, much like the well-known effect of adding electron transport inhibitors. Recent studies reveal that ROS and lipid peroxidation products are effective inhibitors of the electron-transport complexes. In some cases, inactivation of enzymes correlates with chemical modification of only a small number of unusually reactive amino acids. In this article, we review current knowledge of ROS-induced alterations within three complexes: (1) complex IV; (2) complex III; and (3) complex I. Our goal is to identify "hot spots" within each complex that are easily chemically modified and could be responsible for ROS-induced inhibition of the individual complexes. Special attention has been placed on ROS-induced damage to cardiolipin that is tightly bound to each of the inner membrane protein complexes. Peroxidation of the bound cardiolipin is thought to be particularly important since its close proximity and long residence time on the protein make it an especially effective reagent for subsequent ROS-induced damage to these proteins.
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Affiliation(s)
- Andrej Musatov
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA
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31
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Mancuso M, Orsucci D, Filosto M, Simoncini C, Siciliano G. Drugs and mitochondrial diseases: 40 queries and answers. Expert Opin Pharmacother 2012; 13:527-43. [DOI: 10.1517/14656566.2012.657177] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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32
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Dröse S, Brandt U. Molecular mechanisms of superoxide production by the mitochondrial respiratory chain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:145-69. [PMID: 22729857 DOI: 10.1007/978-1-4614-3573-0_6] [Citation(s) in RCA: 359] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mitochondrial respiratory chain is a major source of reactive oxygen species (ROS) in eukaryotic cells. Mitochondrial ROS production associated with a dysfunction of respiratory chain complexes has been implicated in a number of degenerative diseases and biological aging. Recent findings suggest that mitochondrial ROS can be integral components of cellular signal transduction as well. Within the respiratory chain, complexes I (NADH:ubiquinone oxidoreductase) and III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc (1) complex) are generally considered as the main producers of superoxide anions that are released into the mitochondrial matrix and the intermembrane space, respectively. The primary function of both respiratory chain complexes is to employ energy supplied by redox reactions to drive the vectorial transfer of protons into the mitochondrial intermembrane space. This process involves a set of distinct electron carriers designed to minimize the unwanted leak of electrons from reduced cofactors onto molecular oxygen and hence ROS generation under normal circumstances. Nevertheless, it seems plausible that superoxide is derived from intermediates of the normal catalytic cycles of complexes I and III. Therefore, a detailed understanding of the molecular mechanisms driving these enzymes is required to understand mitochondrial ROS production during oxidative stress and redox signalling. This review summarizes recent findings on the chemistry and control of the reactions within respiratory complexes I and III that result in increased superoxide generation. Regulatory contributions of other components of the respiratory chain, especially complex II (succinate:ubiquinone oxidoreductase) and the redox state of the ubiquinone pool (Q-pool) will be briefly discussed.
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Affiliation(s)
- Stefan Dröse
- Center for Membrane Proteomics, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
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33
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Su T, Esser L, Xia D, Yu CA, Yu L. Generation, characterization and crystallization of a cytochrome c(1)-subunit IV fused cytochrome bc(1) complex from Rhodobacter sphaeroides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:298-305. [PMID: 22050933 DOI: 10.1016/j.bbabio.2011.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 10/17/2011] [Accepted: 10/18/2011] [Indexed: 11/15/2022]
Abstract
Cytochrome bc(1) complex catalyzes the reaction of electron transfer from ubiquinol to cytochrome c (or cytochrome c(2)) and couples this reaction to proton translocation across the membrane. Crystallization of the Rhodobacter sphaeroides bc(1) complex resulted in crystals containing only three core subunits. To mitigate the problem of subunit IV being dissociated from the three-subunit core complex during crystallization, we recently engineered an R. sphaeroides mutant in which the N-terminus of subunit IV was fused to the C-terminus of cytochrome c(1) with a 14-glycine linker between the two fusing subunits, and a 6-histidine tag at the C-terminus of subunit IV (c(1)-14Gly-IV-6His). The purified fusion mutant complex shows higher electron transfer activity, more structural stability, and less superoxide generation as compared to the wild-type enzyme. Preliminary crystallization attempts with this mutant complex yielded crystals containing four subunits and diffracting X-rays to 5.5Å resolution.
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Affiliation(s)
- Ting Su
- Department of Biochemistry & Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
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