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Sabir JSM, Rabah S, Yacoub H, Hajrah NH, Atef A, Al-Matary M, Edris S, Alharbi MG, Ganash M, Mahyoub J, Al-Hindi RR, Al-Ghamdi KM, Hall N, Bahieldin A, Kamli MR, Rather IA. Molecular evolution of cytochrome C oxidase-I protein of insects living in Saudi Arabia. PLoS One 2019; 14:e0224336. [PMID: 31682609 PMCID: PMC6827904 DOI: 10.1371/journal.pone.0224336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/10/2019] [Indexed: 11/19/2022] Open
Abstract
The study underpins barcode characterization of insect species collected from Saudi Arabia and explored functional constraints during evolution at the DNA and protein levels to expect the possible mechanisms of protein evolution in insects. Codon structure designated AT-biased insect barcode of the cytochrome C oxidase I (COI). In addition, the predicted 3D structure of COI protein indicated tyrosine in close proximity with the heme ligand, depicted substitution to phenylalanine in two Hymenopteran species. This change resulted in the loss of chemical bonding with the heme ligand. The estimated nucleotide substitution matrices in insect COI barcode generally showed a higher probability of transversion compared with the transition. Computations of codon-by-codon nonsynonymous substitutions in Hymenopteran and Hemipteran species indicated that almost half of the codons are under positive evolution. Nevertheless, codons of COI barcode of Coleoptera, Lepidoptera and Diptera are mostly under purifying selection. The results reinforce that codons in helices 2, 5 and 6 and those in loops 2–3 and 5–6 are mostly conserved and approach strong purifying selection. The overall results argue the possible evolutionary position of Hymenopteran species among those of other insects.
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Affiliation(s)
- Jamal S. M. Sabir
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Samar Rabah
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Haitham Yacoub
- Department of Biological Sciences, Faculty of Science, University of Jeddah, Dahaban, Saudi Arabia
| | - Nahid H. Hajrah
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Ahmed Atef
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Mohammed Al-Matary
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Sherif Edris
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
- Department of Genetics, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
- Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), Faculty of Medicine, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Mona G. Alharbi
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Magdah Ganash
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Jazem Mahyoub
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Rashad R. Al-Hindi
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Khalid M. Al-Ghamdi
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Neil Hall
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
- The Genome Analysis Center, Norwich Research Park, Norwich, United Kingdom
| | - Ahmed Bahieldin
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
- Department of Genetics, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
| | - Majid R. Kamli
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
| | - Irfan A. Rather
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah, Saudi Arabia
- * E-mail: ,
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52
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Suga M, Shimada A, Akita F, Shen JR, Tosha T, Sugimoto H. Time-resolved studies of metalloproteins using X-ray free electron laser radiation at SACLA. Biochim Biophys Acta Gen Subj 2019; 1864:129466. [PMID: 31678142 DOI: 10.1016/j.bbagen.2019.129466] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND The invention of the X-ray free-electron laser (XFEL) has provided unprecedented new opportunities for structural biology. The advantage of XFEL is an intense pulse of X-rays and a very short pulse duration (<10 fs) promising a damage-free and time-resolved crystallography approach. SCOPE OF REVIEW Recent time-resolved crystallographic analyses in XFEL facility SACLA are reviewed. Specifically, metalloproteins involved in the essential reactions of bioenergy conversion including photosystem II, cytochrome c oxidase and nitric oxide reductase are described. MAJOR CONCLUSIONS XFEL with pump-probe techniques successfully visualized the process of the reaction and the dynamics of a protein. Since the active center of metalloproteins is very sensitive to the X-ray radiation, damage-free structures obtained by XFEL are essential to draw mechanistic conclusions. Methods and tools for sample delivery and reaction initiation are key for successful measurement of the time-resolved data. GENERAL SIGNIFICANCE XFEL is at the center of approaches to gain insight into complex mechanism of structural dynamics and the reactions catalyzed by biological macromolecules. Further development has been carried out to expand the application of time-resolved X-ray crystallography. This article is part of a Special Issue entitled Novel measurement techniques for visualizing 'live' protein molecules.
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Affiliation(s)
- Michihiro Suga
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan..
| | - Atsuhiro Shimada
- Graduate School of Applied Biological Sciences and Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan..
| | - Fusamichi Akita
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan
| | - Takehiko Tosha
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hiroshi Sugimoto
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan..
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53
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Capitanio G, Palese LL, Papa F, Papa S. Allosteric Cooperativity in Proton Energy Conversion in A1-Type Cytochrome c Oxidase. J Mol Biol 2019; 432:534-551. [PMID: 31626808 DOI: 10.1016/j.jmb.2019.09.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/06/2019] [Accepted: 09/24/2019] [Indexed: 12/30/2022]
Abstract
Cytochrome c oxidase (CcO), the CuA, heme a, heme a3, CuB enzyme of respiratory chain, converts the free energy released by aerobic cytochrome c oxidation into a membrane electrochemical proton gradient (ΔμH+). ΔμH+ derives from the membrane anisotropic arrangement of dioxygen reduction to two water molecules and transmembrane proton pumping from a negative (N) space to a positive (P) space separated by the membrane. Spectroscopic, potentiometric, and X-ray crystallographic analyses characterize allosteric cooperativity of dioxygen binding and reduction with protonmotive conformational states of CcO. These studies show that allosteric cooperativity stabilizes the favorable conformational state for conversion of redox energy into a transmembrane ΔμH+.
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Affiliation(s)
- Giuseppe Capitanio
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124 Bari, Italy
| | - Luigi Leonardo Palese
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124 Bari, Italy
| | - Francesco Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124 Bari, Italy
| | - Sergio Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", 70124 Bari, Italy; Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy.
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54
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Abstract
X-ray crystallographic analyses of mitochondrial cytochrome c oxidase (CcO) have been based on its dimeric form. Recent cryo-electron microscopy structures revealed that CcO exists in its monomeric form in the respiratory supercomplex. This study, using amphipol-stabilized CcO, shows that the activity of monomer is higher than that of the dimer. The crystal structure of monomer determined here shows that the local structure of one of the proton transfer pathways differs from that in the dimer. The crystal structure also shows that cardiolipins are located at the interface region in the supercomplex. Taken together, these results suggest that CcO in the monomeric state, dimeric state, and supercomplex state depending on cardiolipins are involved in regulation of respiratory electron transport. Cytochrome c oxidase (CcO), a membrane enzyme in the respiratory chain, catalyzes oxygen reduction by coupling electron and proton transfer through the enzyme with a proton pump across the membrane. In all crystals reported to date, bovine CcO exists as a dimer with the same intermonomer contacts, whereas CcOs and related enzymes from prokaryotes exist as monomers. Recent structural analyses of the mitochondrial respiratory supercomplex revealed that CcO monomer associates with complex I and complex III, indicating that the monomeric state is functionally important. In this study, we prepared monomeric and dimeric bovine CcO, stabilized using amphipol, and showed that the monomer had high activity. In addition, using a newly synthesized detergent, we determined the oxidized and reduced structures of monomer with resolutions of 1.85 and 1.95 Å, respectively. Structural comparison of the monomer and dimer revealed that a hydrogen bond network of water molecules is formed at the entry surface of the proton transfer pathway, termed the K-pathway, in monomeric CcO, whereas this network is altered in dimeric CcO. Based on these results, we propose that the monomer is the activated form, whereas the dimer can be regarded as a physiological standby form in the mitochondrial membrane. We also determined phospholipid structures based on electron density together with the anomalous scattering effect of phosphorus atoms. Two cardiolipins are found at the interface region of the supercomplex. We discuss formation of the monomeric CcO, dimeric CcO, and supercomplex, as well as their role in regulation of CcO activity.
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55
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Malkamäki A, Meunier B, Reidelbach M, Rich PR, Sharma V. The H channel is not a proton transfer path in yeast cytochrome c oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:717-723. [PMID: 31374214 DOI: 10.1016/j.bbabio.2019.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/24/2019] [Accepted: 07/29/2019] [Indexed: 10/26/2022]
Abstract
Cytochrome c oxidases (CcOs) in the respiratory chains of mitochondria and bacteria are primary consumers of molecular oxygen, converting it to water with the concomitant pumping of protons across the membrane to establish a proton electrochemical gradient. Despite a relatively well understood proton pumping mechanism of bacterial CcOs, the role of the H channel in mitochondrial forms of CcO remains debated. Here, we used site-directed mutagenesis to modify a central residue of the lower span of the H channel, Q413, in the genetically tractable yeast Saccharomyces cerevisiae. Exchange of Q413 to several different amino acids showed no effect on rates and efficiencies of respiratory cell growth, and redox potential measurements indicated minimal electrostatic interaction between the 413 locus and the nearest redox active component heme a. These findings clearly exclude a primary role of this section of the H channel in proton pumping in yeast CcO. In agreement with the experimental data, atomistic molecular dynamics simulations and continuum electrostatic calculations on wildtype and mutant yeast CcOs highlight potential bottlenecks in proton transfer through this route. Our data highlight the preference for neutral residues in the 413 locus, precluding sufficient hydration for formation of a proton conducting wire.
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Affiliation(s)
- Aapo Malkamäki
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland
| | - Brigitte Meunier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Université Paris Saclay, 91198 Gif sur Yvette, France
| | - Marco Reidelbach
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland
| | - Peter R Rich
- Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Vivek Sharma
- Department of Physics, P. O. Box 64, University of Helsinki, 00014 Helsinki, Finland; Institute of Biotechnology, P. O. Box 56, University of Helsinki, 00014 Helsinki, Finland.
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56
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Worthy HL, Auhim HS, Jamieson WD, Pope JR, Wall A, Batchelor R, Johnson RL, Watkins DW, Rizkallah P, Castell OK, Jones DD. Positive functional synergy of structurally integrated artificial protein dimers assembled by Click chemistry. Commun Chem 2019. [DOI: 10.1038/s42004-019-0185-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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57
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Saura P, Frey DM, Gamiz-Hernandez AP, Kaila VRI. Electric field modulated redox-driven protonation and hydration energetics in energy converting enzymes. Chem Commun (Camb) 2019; 55:6078-6081. [PMID: 31066378 PMCID: PMC6932871 DOI: 10.1039/c9cc01135h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Biological energy conversion is catalysed by proton-coupled electron transfer (PCET) reactions that form the chemical basis of respiratory and photosynthetic enzymes. Despite recent advances in structural, biophysical, and computational experiments, the mechanistic principles of these reactions still remain elusive. Based on common functional features observed in redox enzymes, we study here generic mechanistic models for water-mediated long-range PCET reactions. We show how a redox reaction within a buried protein environment creates an electric field that induces hydration changes between the proton acceptor and donor groups, and in turn, lowers the reaction barrier and increases the thermodynamic driving forces for the water-mediated PCET process. We predict linear free energy relationships, and discuss the proposed mechanism in context of PCET in cytochrome c oxidase.
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Affiliation(s)
- Patricia Saura
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85748, Garching, Germany.
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58
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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59
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Sharma P, Maklashina E, Cecchini G, Iverson TM. Maturation of the respiratory complex II flavoprotein. Curr Opin Struct Biol 2019; 59:38-46. [PMID: 30851631 DOI: 10.1016/j.sbi.2019.01.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 12/13/2022]
Abstract
Respiratory complexes are complicated multi-subunit cofactor-containing machines that allow cells to harvest energy from the environment. Maturation of these complexes requires protein folding, cofactor insertion, and assembly of multiple subunits into a final, functional complex. Because the intermediate states in complex maturation are transitory, these processes are poorly understood. This review gives an overview of the process of maturation in respiratory complex II with a focus on recent structural studies on intermediates formed during covalent flavinylation of the catalytic subunit, SDHA. Covalent flavinylation has an evolutionary significance because variants of complex II enzymes with the covalent ligand removed by mutagenesis cannot oxidize succinate, but can still perform the reverse reaction and reduce fumarate. Since succinate oxidation is a key step of aerobic respiration, the covalent bond of complex II appears to be important for aerobic life.
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Affiliation(s)
- Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Elena Maklashina
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121, United States; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158, United States.
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, United States; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, United States; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, United States.
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60
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Snapshot of an oxygen intermediate in the catalytic reaction of cytochrome c oxidase. Proc Natl Acad Sci U S A 2019; 116:3572-3577. [PMID: 30808749 DOI: 10.1073/pnas.1814526116] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytochrome c oxidase (CcO) reduces dioxygen to water and harnesses the chemical energy to drive proton translocation across the inner mitochondrial membrane by an unresolved mechanism. By using time-resolved serial femtosecond crystallography, we identified a key oxygen intermediate of bovine CcO. It is assigned to the PR-intermediate, which is characterized by specific redox states of the metal centers and a distinct protein conformation. The heme a 3 iron atom is in a ferryl (Fe4+ = O2-) configuration, and heme a and CuB are oxidized while CuA is reduced. A Helix-X segment is poised in an open conformational state; the heme a farnesyl sidechain is H-bonded to S382, and loop-I-II adopts a distinct structure. These data offer insights into the mechanism by which the oxygen chemistry is coupled to unidirectional proton translocation.
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61
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Shen X, Pu Z, Chen X, Murphy RW, Shen Y. Convergent Evolution of Mitochondrial Genes in Deep-Sea Fishes. Front Genet 2019; 10:925. [PMID: 31632444 PMCID: PMC6785628 DOI: 10.3389/fgene.2019.00925] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/04/2019] [Indexed: 02/05/2023] Open
Abstract
Deep seas have extremely harsh conditions including high hydrostatic pressure, total darkness, cold, and little food and oxygen. The adaptations of fishes to deep-sea environment apparently have occurred independently many times. The genetic basis of adaptation for obtaining their energy remains unknown. Mitochondria play a central role in aerobic respiration. Analyses of the available 2,161 complete mitochondrial genomes of 1,042 fishes, including 115 deep-sea species, detect signals of positive selection in mitochondrial genes in nine branches of deep-sea fishes. Aerobic metabolism yields much more energy per unit of source material than anaerobic metabolism. The adaptive evolution of the mtDNA may reflect that aerobic metabolism plays a more important role than anaerobic metabolism in deep-sea fishes, whose energy sources (food) are extremely limited. This strategy maximizes the usage of energy sources. Eleven mitochondrial genes have convergent/parallel amino acid changes between branches of deep-sea fishes. Thus, these amino acid sites may be functionally important in the acquisition of energy, and reflect convergent evolution during their independent invasion of the harsh deep-sea ecological niche.
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Affiliation(s)
- Xuejuan Shen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhiqing Pu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xiao Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Robert W. Murphy
- Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, Toronto, ON, Canada
| | - Yongyi Shen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, South China Agricultural University, Guangzhou, China
- Joint Influenza Research Centre (SUMC/HKU), Shantou University Medical College, Shantou, China
- *Correspondence: Yongyi Shen,
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62
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Rathore S, Berndtsson J, Marin-Buera L, Conrad J, Carroni M, Brzezinski P, Ott M. Cryo-EM structure of the yeast respiratory supercomplex. Nat Struct Mol Biol 2018; 26:50-57. [PMID: 30598556 DOI: 10.1038/s41594-018-0169-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/14/2018] [Indexed: 01/08/2023]
Abstract
Respiratory chain complexes execute energy conversion by connecting electron transport with proton translocation over the inner mitochondrial membrane to fuel ATP synthesis. Notably, these complexes form multi-enzyme assemblies known as respiratory supercomplexes. Here we used single-particle cryo-EM to determine the structures of the yeast mitochondrial respiratory supercomplexes III2IV and III2IV2, at 3.2-Å and 3.5-Å resolutions, respectively. We revealed the overall architecture of the supercomplex, which deviates from the previously determined assemblies in mammals; obtained a near-atomic structure of the yeast complex IV; and identified the protein-protein and protein-lipid interactions implicated in supercomplex formation. Take together, our results demonstrate convergent evolution of supercomplexes in mitochondria that, while building similar assemblies, results in substantially different arrangements and structural solutions to support energy conversion.
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Affiliation(s)
- Sorbhi Rathore
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Jens Berndtsson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Lorena Marin-Buera
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Julian Conrad
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Marta Carroni
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.,Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
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63
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Structure of yeast cytochrome c oxidase in a supercomplex with cytochrome bc 1. Nat Struct Mol Biol 2018; 26:78-83. [PMID: 30598554 PMCID: PMC6330080 DOI: 10.1038/s41594-018-0172-z] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/21/2018] [Indexed: 01/24/2023]
Abstract
Cytochrome c oxidase (complex IV, CIV) is known in mammals to exist independently or in association with other respiratory proteins to form supercomplexes (SCs). In Saccharomyces cerevisiae, CIV is found solely in an SC with cytochrome bc1 (complex III, CIII). Here, we present the cryogenic electron microscopy (cryo-EM) structure of S. cerevisiae CIV in a III2IV2 SC at 3.3 Å resolution. While overall similarity to mammalian homologs is high, we found notable differences in the supernumerary subunits Cox26 and Cox13; the latter exhibits a unique arrangement that precludes CIV dimerization as seen in bovine. A conformational shift in the matrix domain of Cox5A-involved in allosteric inhibition by ATP-may arise from its association with CIII. The CIII-CIV arrangement highlights a conserved interaction interface of CIII, albeit one occupied by complex I in mammalian respirasomes. We discuss our findings in the context of the potential impact of SC formation on CIV regulation.
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64
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Adam SM, Wijeratne GB, Rogler PJ, Diaz DE, Quist DA, Liu JJ, Karlin KD. Synthetic Fe/Cu Complexes: Toward Understanding Heme-Copper Oxidase Structure and Function. Chem Rev 2018; 118:10840-11022. [PMID: 30372042 PMCID: PMC6360144 DOI: 10.1021/acs.chemrev.8b00074] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heme-copper oxidases (HCOs) are terminal enzymes on the mitochondrial or bacterial respiratory electron transport chain, which utilize a unique heterobinuclear active site to catalyze the 4H+/4e- reduction of dioxygen to water. This process involves a proton-coupled electron transfer (PCET) from a tyrosine (phenolic) residue and additional redox events coupled to transmembrane proton pumping and ATP synthesis. Given that HCOs are large, complex, membrane-bound enzymes, bioinspired synthetic model chemistry is a promising approach to better understand heme-Cu-mediated dioxygen reduction, including the details of proton and electron movements. This review encompasses important aspects of heme-O2 and copper-O2 (bio)chemistries as they relate to the design and interpretation of small molecule model systems and provides perspectives from fundamental coordination chemistry, which can be applied to the understanding of HCO activity. We focus on recent advancements from studies of heme-Cu models, evaluating experimental and computational results, which highlight important fundamental structure-function relationships. Finally, we provide an outlook for future potential contributions from synthetic inorganic chemistry and discuss their implications with relevance to biological O2-reduction.
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Affiliation(s)
- Suzanne M. Adam
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gayan B. Wijeratne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Patrick J. Rogler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Daniel E. Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeffrey J. Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Shimada A, Hatano K, Tadehara H, Yano N, Shinzawa-Itoh K, Yamashita E, Muramoto K, Tsukihara T, Yoshikawa S. X-ray structural analyses of azide-bound cytochrome c oxidases reveal that the H-pathway is critically important for the proton-pumping activity. J Biol Chem 2018; 293:14868-14879. [PMID: 30077971 PMCID: PMC6153300 DOI: 10.1074/jbc.ra118.003123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 07/31/2018] [Indexed: 01/07/2023] Open
Abstract
Cytochrome c oxidase (CcO) is the terminal oxidase of cellular respiration, reducing O2 to water and pumping protons. X-ray structural features have suggested that CcO pumps protons via a mechanism involving electrostatic repulsions between pumping protons in the hydrogen-bond network of a proton-conducting pathway (the H-pathway) and net positive charges created upon oxidation of an iron site, heme a (Fe a2+), for reduction of O2 at another iron site, heme a3 (Fe a32+). The protons for pumping are transferred to the hydrogen-bond network from the N-side via the water channel of the H-pathway. Back-leakage of protons to the N-side is thought to be blocked by closure of the water channel. To experimentally test this, we examined X-ray structures of the azide-bound, oxidized bovine CcO and found that an azide derivative (N3--Fe a33+, CuB2+-N3-) induces a translational movement of the heme a3 plane. This was accompanied by opening of the water channel, revealing that Fe a3 and the H-pathway are tightly coupled. The channel opening in the oxidized state is likely to induce back-leakage of pumping protons, which lowers the proton level in the hydrogen-bond network during enzymatic turnover. The proton level decrease weakens the electron affinity of Fe a , if Fe a electrostatically interacts with protons in the hydrogen-bond network. The previously reported azide-induced redox-potential decrease in Fe a supports existence of the electrostatic interaction. In summary, our results indicate that the H-pathway is critical for CcO's proton-pumping function.
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Affiliation(s)
| | | | | | | | | | - Eiki Yamashita
- the Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, and
| | - Kazumasa Muramoto
- Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akoh, Hyogo 678-1297, , To whom correspondence may be addressed:
Dept. of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akoh, Hyogo 678-1297, Japan. E-mail:
| | - Tomitake Tsukihara
- From the Picobiology Institute and ,the Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, and ,the Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan, To whom correspondence may be addressed:
Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akoh, Hyogo 678-1297, Japan. E-mail:
| | - Shinya Yoshikawa
- From the Picobiology Institute and , To whom correspondence may be addressed:
Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akoh, Hyogo 678-1297, Japan. Tel.:
81-791-58-0189; E-mail:
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66
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Hemschemeier A, Happe T. The plasticity of redox cofactors: from metalloenzymes to redox-active DNA. Nat Rev Chem 2018. [DOI: 10.1038/s41570-018-0029-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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67
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Farahvash A, Stuchebrukhov A. Investigating the Many Roles of Internal Water in Cytochrome c Oxidase. J Phys Chem B 2018; 122:7625-7635. [PMID: 30011995 DOI: 10.1021/acs.jpcb.7b11920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cytochrome c oxidase (C cO) is the terminal enzyme in the respiratory electron transport chain. As part of its catalytic cycle, C cO transfers protons to its Fe-Cu binuclear center (BNC) to reduce oxygen, and in addition, it pumps protons across the mitochondrial inner, or bacterial, membrane where it is located. It is believed that this proton transport is facilitated by a network of water chains inside the enzyme. Here we present an analysis of the hydration of C cO, including the BNC region, using a semi-empirical hydration program, Dowser++, recently developed in our group. Using high-resolution X-ray data, we show that Dowser++ predictions match very accurately the water molecules seen in the D- and K-channels of C cO, as well as in the vicinity of its BNC. Moreover, Dowser++ predicts many more internal water molecules than is typically seen in the experiment. However, no significant hydration of the catalytic cavity in C cO described recently in the literature is observed. As Dowser++ itself does not account for structural changes of the protein, this result supports the earlier assessment that the proposed wetting transition in the catalytic cavity can only either be due to structural rearrangements of BNC, possibly induced by the charges during the catalytic cycle, or occur transiently, in concert with the proton transfer. Molecular dynamics simulations were performed to investigate the global dynamic nature of Dowser++ waters in C cO, and the results suggest a consistent explanation as to why some predicted water molecules would be missing in the experimental structures. Furthermore, in light of the significant protein hydration predicted by Dowser++, the dielectric constant of the hydrated cavities in C cO was also investigated using the Fröhlich-Kirkwood model; the results indicate that in the cavities where water is packed sufficiently densely the dielectric constant can approach values comparable even to that of bulk water.
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Affiliation(s)
- Ardavan Farahvash
- Department of Chemistry , University of California-Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Alexei Stuchebrukhov
- Department of Chemistry , University of California-Davis , One Shields Avenue , Davis , California 95616 , United States
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68
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Supekar S, Kaila VRI. Dewetting transitions coupled to K-channel activation in cytochrome c oxidase. Chem Sci 2018; 9:6703-6710. [PMID: 30310604 PMCID: PMC6115622 DOI: 10.1039/c8sc01587b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 07/08/2018] [Indexed: 12/20/2022] Open
Abstract
Cytochrome c oxidase (CcO) drives aerobic respiratory chains in all organisms by transducing the free energy from oxygen reduction into an electrochemical proton gradient across a biological membrane.
Cytochrome c oxidase (CcO) drives aerobic respiratory chains in all organisms by transducing the free energy from oxygen reduction into an electrochemical proton gradient across a biological membrane. CcO employs the so-called D- and K-channels for proton uptake, but the molecular mechanism for activation of the K-channel has remained elusive for decades. We show here by combining large-scale atomistic molecular simulations with graph-theoretical water network analysis, and hybrid quantum/classical (QM/MM) free energy calculations, that the K-channel is activated by formation of a reactive oxidized intermediate in the binuclear heme a3/CuB active site. This state induces electrostatic, hydration, and conformational changes that lower the barrier for proton transfer along the K-channel by dewetting pathways that connect the D-channel with the active site. Our combined results reconcile previous experimental findings and indicate that water dynamics plays a decisive role in the proton pumping machinery in CcO.
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Affiliation(s)
- Shreyas Supekar
- Department Chemie , Technische Universität München , Lichtenbergstraße 4 , D-85748 Garching , Germany .
| | - Ville R I Kaila
- Department Chemie , Technische Universität München , Lichtenbergstraße 4 , D-85748 Garching , Germany .
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69
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Kopcova K, Blascakova L, Kozar T, Jancura D, Fabian M. Response of Heme Symmetry to the Redox State of Bovine Cytochrome c Oxidase. Biochemistry 2018; 57:4105-4113. [PMID: 29901388 DOI: 10.1021/acs.biochem.8b00459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Second-derivative absorption spectroscopy was employed to monitor the response of effective symmetry of cytochromes a and a3 to the redox and ligation states of bovine cytochrome c oxidase (CcO). The Soret band π → π* electronic transitions were used to display the changes in symmetry of these chromophores induced by the reduction of CcO inhibited by the exogenous ligands and during catalytic turnover. The second derivative of the difference absorption spectra revealed only a single Soret band for the oxidized cytochromes a and a3 and cyanide-ligated oxidized cytochrome a3. In contrast, two absorption bands were resolved in ferrous cytochrome a and ferrous cytochrome a3 ligated with cyanide. A transition from one-band spectrum to two-band spectrum indicates the lowering of symmetry of these hemes due to the alteration of their immediate surroundings. It is suggested that the changes in polarity occurring in the vicinity of these cofactors are main reason for the split of the Soret band of both ferrous cytochrome a and cyanide-bound ferrous cytochrome a3.
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Affiliation(s)
- Katarina Kopcova
- Department of Biophysics, Faculty of Science , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic
| | - Ludmila Blascakova
- Center for Interdisciplinary Biosciences, Technology and Innovation Park , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic
| | - Tibor Kozar
- Center for Interdisciplinary Biosciences, Technology and Innovation Park , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic
| | - Daniel Jancura
- Department of Biophysics, Faculty of Science , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic.,Center for Interdisciplinary Biosciences, Technology and Innovation Park , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic
| | - Marian Fabian
- Center for Interdisciplinary Biosciences, Technology and Innovation Park , University of P. J. Safarik , Jesenna 5 , 041 54 Kosice , Slovak Republic
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70
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Souders CL, Liang X, Wang X, Ector N, Zhao YH, Martyniuk CJ. High-throughput assessment of oxidative respiration in fish embryos: Advancing adverse outcome pathways for mitochondrial dysfunction. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 199:162-173. [PMID: 29631217 DOI: 10.1016/j.aquatox.2018.03.031] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 03/21/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
Mitochondrial dysfunction is a prevalent molecular event that can result in multiple adverse outcomes. Recently, a novel high throughput method to assess metabolic capacity in fish embryos following exposure to chemicals has been adapted for environmental toxicology. Assessments of oxygen consumption rates using the Seahorse XF(e) 24/96 Extracellular Flux Analyzer (Agilent Technologies) can be used to garner insight into toxicant effects at early stages of development. Here we synthesize the current state of the science using high throughput metabolic profiling in zebrafish embryos, and present considerations for those wishing to adopt high throughput methods for mitochondrial bioenergetics into their research. Chemicals that have been investigated in zebrafish using this metabolic platform include herbicides (e.g. paraquat, diquat), industrial compounds (e.g. benzo-[a]-pyrene, tributyltin), natural products (e.g. quercetin), and anti-bacterial chemicals (i.e. triclosan). Some of these chemicals inhibit mitochondrial endpoints in the μM-mM range, and reduce basal respiration, maximum respiration, and spare capacity. We present a theoretical framework for how one can use mitochondrial performance data in zebrafish to categorize chemicals of concern and prioritize mitochondrial toxicants. Noteworthy is that our studies demonstrate that there can be considerable variation in basal respiration of untreated zebrafish embryos due to clutch-specific effects as well as individual variability, and basal oxygen consumption rates (OCR) can vary on average between 100 and 300 pmol/min/embryo. We also compare OCR between chorionated and dechorionated embryos, as both models are employed to test chemicals. After 24 h, dechorionated embryos remain responsive to mitochondrial toxicants, although they show a blunted response to the uncoupling agent carbonylcyanide-4-trifluoromethoxyphenylhydrazone (FCCP); dechorionated embryos are therefore a viable option for investigations into mitochondrial bioenergetics. We present an adverse outcome pathway framework that incorporates endpoints related to mitochondrial bioenergetics. High throughput bioenergetics assays conducted using whole embryos are expected to support adverse outcome pathways for mitochondrial dysfunction.
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Affiliation(s)
- Christopher L Souders
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Xuefang Liang
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA; School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China
| | - Xiaohong Wang
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA; State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, Jilin, 130117, China
| | - Naomi Ector
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Yuan H Zhao
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, Jilin, 130117, China
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA.
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71
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Skibinski DOF, Ghiselli F, Diz AP, Milani L, Mullins JGL. Structure-Related Differences between Cytochrome Oxidase I Proteins in a Stable Heteroplasmic Mitochondrial System. Genome Biol Evol 2018; 9:3265-3281. [PMID: 29149282 PMCID: PMC5726481 DOI: 10.1093/gbe/evx235] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2017] [Indexed: 12/27/2022] Open
Abstract
Many bivalve species have two types of mitochondrial DNA passed independently through the female line (F genome) and male line (M genome). Here we study the cytochrome oxidase I protein in such bivalve species and provide evidence for differences between the F and M proteins in amino acid property values, particularly relating to hydrophobicity and helicity. The magnitude of these differences varies between different regions of the protein and the change from the ancestor is most marked in the M protein. The observed changes occur in parallel and in the same direction in the different species studied. Two possible causes are considered, first relaxation of purifying selection with drift and second positive selection. These may operate in different ways in different regions of the protein. Many different amino acid substitutions contribute in a small way to the observed variation, but substitutions involving alanine and serine have a quantitatively large effect. Some of these substitutions are potential targets for phosphorylation and some are close to residues of functional importance in the catalytic mechanism. We propose that the observed changes in the F and M proteins might contribute to functional differences between them relating to ATP production and mitochondrial membrane potential with implications for sperm function.
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Affiliation(s)
- David O F Skibinski
- Institute of Life Science, Swansea University Medical School, United Kingdom
| | - Fabrizio Ghiselli
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Italy
| | - Angel P Diz
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Spain
| | - Liliana Milani
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Italy
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72
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Sharbrough J, Havird JC, Noe GR, Warren JM, Sloan DB. The Mitonuclear Dimension of Neanderthal and Denisovan Ancestry in Modern Human Genomes. Genome Biol Evol 2018; 9:1567-1581. [PMID: 28854627 PMCID: PMC5509035 DOI: 10.1093/gbe/evx114] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2017] [Indexed: 12/15/2022] Open
Abstract
Some human populations interbred with Neanderthals and Denisovans, resulting in substantial contributions to modern-human genomes. Therefore, it is now possible to use genomic data to investigate mechanisms that shaped historical gene flow between humans and our closest hominin relatives. More generally, in eukaryotes, mitonuclear interactions have been argued to play a disproportionate role in generating reproductive isolation. There is no evidence of mtDNA introgression into modern human populations, which means that all introgressed nuclear alleles from archaic hominins must function on a modern-human mitochondrial background. Therefore, mitonuclear interactions are also potentially relevant to hominin evolution. We performed a detailed accounting of mtDNA divergence among hominin lineages and used population-genomic data to test the hypothesis that mitonuclear incompatibilities have preferentially restricted the introgression of nuclear genes with mitochondrial functions. We found a small but significant underrepresentation of introgressed Neanderthal alleles at such nuclear loci. Structural analyses of mitochondrial enzyme complexes revealed that these effects are unlikely to be mediated by physically interacting sites in mitochondrial and nuclear gene products. We did not detect any underrepresentation of introgressed Denisovan alleles at mitochondrial-targeted loci, but this may reflect reduced power because locus-specific estimates of Denisovan introgression are more conservative. Overall, we conclude that genes involved in mitochondrial function may have been subject to distinct selection pressures during the history of introgression from archaic hominins but that mitonuclear incompatibilities have had, at most, a small role in shaping genome-wide introgression patterns, perhaps because of limited functional divergence in mtDNA and interacting nuclear genes.
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Affiliation(s)
- Joel Sharbrough
- Department of Biology, Colorado State University, Fort Collins, CO
| | - Justin C Havird
- Department of Biology, Colorado State University, Fort Collins, CO
| | - Gregory R Noe
- Department of Biology, Colorado State University, Fort Collins, CO
| | - Jessica M Warren
- Department of Biology, Colorado State University, Fort Collins, CO
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO
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73
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Rocha MC, Springett R. Spectral components of detergent-solubilized bovine cytochrome oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:555-566. [PMID: 29704499 DOI: 10.1016/j.bbabio.2018.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 03/21/2018] [Accepted: 04/23/2018] [Indexed: 11/27/2022]
Abstract
Cytochrome oxidase is the terminal oxidase of the mitochondrial electron transport chain and pumps 4 protons per oxygen reduced to water. Spectral shifts in the α-band of heme a have been observed in multiple studies and these shifts have the potential to shed light on the proton pumping intermediates. Previously we found that heme a had two spectral components in the α-band during redox titrations in living RAW 264.7 mouse macrophage cells, the classical 605 nm form and a blue-shifted 602 nm form. To confirm these spectral changes were not an artifact due to the complex milieu of the living cell, redox titrations were performed in the isolated detergent-solubilized bovine enzyme from both the Soret- and α-band using precise multiwavelength spectroscopy. This data verified the presence of the 602 nm form in the α-band, revealed a similar shift of heme a in the Soret-band and ruled out the reversal of calcium binding as the origin of the blue shift. The 602 nm form was found to be stabilized at high pH or by binding of azide, which is known to blue shift the α-band of heme a. Azide also stabilized the 602 nm form in the living cells. It is concluded there is a form of cytochrome oxidase in which heme a undergoes a blue shift to a 602 nm form and that redox titrations can be successfully performed in living cells where the oxidase operates in its authentic environment and in the presence of a proton motive force.
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Affiliation(s)
- Mariana C Rocha
- Cardiovascular Division, King's College London, British Heart Foundation Centre of Excellence, 125 Coldharbour Lane, London SE5 9NU, United Kingdom
| | - Roger Springett
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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74
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Mahinthichaichan P, Gennis RB, Tajkhorshid E. Cytochrome aa 3 Oxygen Reductase Utilizes the Tunnel Observed in the Crystal Structures To Deliver O 2 for Catalysis. Biochemistry 2018; 57:2150-2161. [PMID: 29546752 DOI: 10.1021/acs.biochem.7b01194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cytochrome aa3 is the terminal respiratory enzyme of all eukaryotes and many bacteria and archaea, reducing O2 to water and harnessing the free energy from the reaction to generate the transmembrane electrochemical potential. The diffusion of O2 to the heme-copper catalytic site, which is buried deep inside the enzyme, is the initiation step of the reaction chemistry. Our previous molecular dynamics (MD) study with cytochrome ba3, a homologous enzyme of cytochrome aa3 in Thermus thermophilus, demonstrated that O2 diffuses from the lipid bilayer to its reduction site through a 25 Å long tunnel inferred by Xe binding sites detected by X-ray crystallography [Mahinthichaichan, P., Gennis, R., and Tajkhorshid, E. (2016) Biochemistry 55, 1265-1278]. Although a similar tunnel is observed in cytochrome aa3, this putative pathway appears partially occluded between the entrances and the reduction site. Also, the experimentally determined second-order rate constant for O2 delivery in cytochrome aa3 (∼108 M-1 s-1) is 10 times slower than that in cytochrome ba3 (∼109 M-1 s-1). A question to be addressed is whether cytochrome aa3 utilizes this X-ray-inferred tunnel as the primary pathway for O2 delivery. Using complementary computational methods, including multiple independent flooding MD simulations and implicit ligand sampling calculations, we probe the O2 delivery pathways in cytochrome aa3 of Rhodobacter sphaeroides. All of the O2 molecules that arrived in the reduction site during the simulations were found to diffuse through the X-ray-observed tunnel, despite its apparent constriction, supporting its role as the main O2 delivery pathway in cytochrome aa3. The rate constant for O2 delivery in cytochrome aa3, approximated using the simulation results, is 10 times slower than in cytochrome ba3, in agreement with the experimentally determined rate constants.
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Affiliation(s)
- Paween Mahinthichaichan
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Robert B Gennis
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Emad Tajkhorshid
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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75
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Zhang SQ, Chino M, Liu L, Tang Y, Hu X, DeGrado WF, Lombardi A. De Novo Design of Tetranuclear Transition Metal Clusters Stabilized by Hydrogen-Bonded Networks in Helical Bundles. J Am Chem Soc 2018; 140:1294-1304. [PMID: 29249157 PMCID: PMC5860638 DOI: 10.1021/jacs.7b08261] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
De novo design provides an attractive approach to test the mechanism by which metalloproteins define the geometry and reactivity of their metal ion cofactors. While there has been considerable progress in designing proteins that bind transition metal ions including iron-sulfur clusters, the design of tetranuclear clusters with oxygen-rich environments has not been accomplished. Here, we describe the design of tetranuclear clusters, consisting of four Zn2+ and four carboxylate oxygens situated at the vertices of a distorted cube-like structure. The tetra-Zn2+ clusters are bound at a buried site within a four-helix bundle, with each helix donating a single carboxylate (Glu or Asp) and imidazole (His) ligand, as well as second- and third-shell ligands. Overall, the designed site consists of four Zn2+ and 16 polar side chains in a fully connected hydrogen-bonded network. The designed proteins have apolar cores at the top and bottom of the bundle, which drive the assembly of the liganding residues near the center of the bundle. The steric bulk of the apolar residues surrounding the binding site was varied to determine how subtle changes in helix-helix packing affect the binding site. The crystal structures of two of four proteins synthesized were in good agreement with the overall design; both formed a distorted cuboidal site stabilized by flanking second- and third-shell interactions that stabilize the primary ligands. A third structure bound a single Zn2+ in an unanticipated geometry, and the fourth bound multiple Zn2+ at multiple sites at partial occupancy. The metal-binding and conformational properties of the helical bundles in solution, probed by circular dichroism spectroscopy, analytical ultracentrifugation, and NMR, were consistent with the crystal structures.
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Affiliation(s)
- Shao-Qing Zhang
- Department of Chemistry, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104-6396, United States
- Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA 94158-9001, United States
| | - Marco Chino
- Department of Chemical Sciences, University of Napoli “Federico II”, Via Cintia, 46, I-80126 Napoli, Italy
| | - Lijun Liu
- Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA 94158-9001, United States
- DLX Scientific, Lawrence, KS 66049, United States
| | - Youzhi Tang
- Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA 94158-9001, United States
- College of Veterinary Medicine, South China Agricultural University, Guangdong 510642, China
| | - Xiaozhen Hu
- Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA 94158-9001, United States
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California at San Francisco, San Francisco, CA 94158-9001, United States
| | - Angela Lombardi
- Department of Chemical Sciences, University of Napoli “Federico II”, Via Cintia, 46, I-80126 Napoli, Italy
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76
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Luo F, Shinzawa-Itoh K, Hagimoto K, Shimada A, Shimada S, Yamashita E, Yoshikawa S, Tsukihara T. Structure of bovine cytochrome c oxidase in the ligand-free reduced state at neutral pH. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2018; 74:92-98. [PMID: 29400318 PMCID: PMC5947679 DOI: 10.1107/s2053230x17018532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/30/2017] [Indexed: 12/03/2022]
Abstract
Although the enzymatic activity of cytochrome c oxidase (CcO) depends sensitively on pH over a wide range, X-ray structural analyses of bovine CcO have been conducted using crystals prepared at pH 5.7 owing to the difficulty in crystallizing this protein. Here, the structure of ligand-free reduced CcO was successfully determined at 1.99 Å resolution. Cytochrome c oxidase (CcO), the terminal oxidase in cellular respiration, couples proton pumping to O2 reduction. Mammalian CcO resides in the inner mitochondrial membrane. Previously, a model of H-pathway proton pumping was proposed based on various CcO crystal structures. However, all previously determined structures were solved using crystals obtained at pH 5.7, which differs from the environmental pH of CcO in the inner membrane. The structures of fully oxidized and ligand-free reduced CcO at pH 7.3 have now been determined. Structural comparison between the oxidized and reduced states revealed that the structural alterations that occurred upon redox change at pH 5.7 in Asp51, the magnesium-containing cluster, haem groups and helix X, which provide important structural evidence for the H-pathway proton-pumping proposal, also occur at pH 7.3. These structural alterations were restricted to a local region of CcO; no domain movement was detected, nor were significant structural alterations detected in peripheral regions at either pH value. These observations indicate that the small and precise structural alterations that occur over the course of the reaction cycle are not affected by pH change, and that isolated CcO precisely performs proton pumping via the H-pathway over a wide pH range. Because the pH is not uniform across the molecular surface of CcO, the fact that the overall structure of CcO is not affected by pH changes ensures the high enzymatic efficiency of this protein in the mitochondria.
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Affiliation(s)
- Fangjia Luo
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Kaede Hagimoto
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Satoru Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-kun, Hyogo 678-1297, Japan
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77
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Wikström M, Krab K, Sharma V. Oxygen Activation and Energy Conservation by Cytochrome c Oxidase. Chem Rev 2018; 118:2469-2490. [PMID: 29350917 PMCID: PMC6203177 DOI: 10.1021/acs.chemrev.7b00664] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
This review focuses on the type
A cytochrome c oxidases (CcO), which
are found in all mitochondria
and also in several aerobic bacteria. CcO catalyzes
the respiratory reduction of dioxygen (O2) to water by
an intriguing mechanism, the details of which are fairly well understood
today as a result of research for over four decades. Perhaps even
more intriguingly, the membrane-bound CcO couples
the O2 reduction chemistry to translocation of protons
across the membrane, thus contributing to generation of the electrochemical
proton gradient that is used to drive the synthesis of ATP as catalyzed
by the rotary ATP synthase in the same membrane. After reviewing the
structure of the core subunits of CcO, the active
site, and the transfer paths of electrons, protons, oxygen, and water,
we describe the states of the catalytic cycle and point out the few
remaining uncertainties. Finally, we discuss the mechanism of proton
translocation and the controversies in that area that still prevail.
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Affiliation(s)
- Mårten Wikström
- Institute of Biotechnology , University of Helsinki , P.O. Box 56 , Helsinki FI-00014 , Finland
| | - Klaas Krab
- Department of Molecular Cell Physiology , Vrije Universiteit , P.O. Box 7161 , Amsterdam 1007 MC , The Netherlands
| | - Vivek Sharma
- Institute of Biotechnology , University of Helsinki , P.O. Box 56 , Helsinki FI-00014 , Finland.,Department of Physics , University of Helsinki , P.O. Box 64 , Helsinki FI-00014 , Finland
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78
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Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
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Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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79
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Sharma V, Jambrina PG, Kaukonen M, Rosta E, Rich PR. Insights into functions of the H channel of cytochrome c oxidase from atomistic molecular dynamics simulations. Proc Natl Acad Sci U S A 2017; 114:E10339-E10348. [PMID: 29133387 PMCID: PMC5715751 DOI: 10.1073/pnas.1708628114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Proton pumping A-type cytochrome c oxidase (CcO) terminates the respiratory chains of mitochondria and many bacteria. Three possible proton transfer pathways (D, K, and H channels) have been identified based on structural, functional, and mutational data. Whereas the D channel provides the route for all pumped protons in bacterial A-type CcOs, studies of bovine mitochondrial CcO have led to suggestions that its H channel instead provides this route. Here, we have studied H-channel function by performing atomistic molecular dynamics simulations on the entire, as well as core, structure of bovine CcO in a lipid-solvent environment. The majority of residues in the H channel do not undergo large conformational fluctuations. Its upper and middle regions have adequate hydration and H-bonding residues to form potential proton-conducting channels, and Asp51 exhibits conformational fluctuations that have been observed crystallographically. In contrast, throughout the simulations, we do not observe transient water networks that could support proton transfer from the N phase toward heme a via neutral His413, regardless of a labile H bond between Ser382 and the hydroxyethylfarnesyl group of heme a In fact, the region around His413 only became sufficiently hydrated when His413 was fixed in its protonated imidazolium state, but its calculated pKa is too low for this to provide the means to create a proton transfer pathway. Our simulations show that the electric dipole moment of residues around heme a changes with the redox state, hence suggesting that the H channel could play a more general role as a dielectric well.
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Affiliation(s)
- Vivek Sharma
- Department of Physics, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Pablo G Jambrina
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Markus Kaukonen
- Department of Physics, University of Helsinki, FI-00014, Helsinki, Finland
| | - Edina Rosta
- Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
| | - Peter R Rich
- Institute of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
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80
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Kitazoe Y, Hasegawa M, Tanaka M, Futami M, Futami J. Mitochondrial determinants of mammalian longevity. Open Biol 2017; 7:rsob.170083. [PMID: 29070610 PMCID: PMC5666079 DOI: 10.1098/rsob.170083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/30/2017] [Indexed: 12/18/2022] Open
Abstract
Current ageing theories are far from satisfactory because of the many determinants involved in ageing. The well-known rate-of-living theory assumes that the product (lifetime energy expenditure, LEE) of maximum lifespan (MLS) and mass-specific basal metabolic rate (msBMR) is approximately constant. Although this theory provides a significant inverse correlation between msBMR and MLS as a whole for mammals, it remains problematic for two reasons. First, several interspecies studies within respective orders (typically within rodents) have shown no inverse relationships between msBMR and MLS. Second, LEE values widely vary in mammals and birds. Here, to solve these two problems, we introduced a new quantity designated as mitochondrial (mt) lifetime energy output, mtLEO = MLS × mtMR, in place of LEE, by using the mt metabolic rate (mtMR) per mitochondrion. Thereby, we found that mtLEO values were distributed more narrowly than LEE ones, and strongly correlated with the four amino-acid variables (AAVs) of Ser, Thr and Cys contents and hydrophobicity of mtDNA-encoded membrane proteins (these variables were related to the stability of these proteins). Consequently, only these two mt items, mtMR and the AAVs, solved the above-mentioned problems in the rate-of-living theory, and thus extensively improved the correlation with MLS compared with that given by LEE.
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Affiliation(s)
- Yasuhiro Kitazoe
- Center of Medical Information Science, Kochi Medical School, Nankoku, Kochi 783-8505, Japan
| | - Masami Hasegawa
- Institute of Statistical Mathematics, Midori-cho 10-3, Tachikawa, Tokyo 190-8562, Japan
| | - Masashi Tanaka
- Department of Genomics for Longevity and Health, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi, Tokyo 173-0015, Japan
| | - Midori Futami
- Department of Biomedical Engineering, Faculty of Engineering, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005, Japan
| | - Junichiro Futami
- Department of Biotechnology, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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81
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Valach M, Moreira S, Hoffmann S, Stadler PF, Burger G. Keeping it complicated: Mitochondrial genome plasticity across diplonemids. Sci Rep 2017; 7:14166. [PMID: 29074957 PMCID: PMC5658414 DOI: 10.1038/s41598-017-14286-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/06/2017] [Indexed: 01/30/2023] Open
Abstract
Chromosome rearrangements are important drivers in genome and gene evolution, with implications ranging from speciation to development to disease. In the flagellate Diplonema papillatum (Euglenozoa), mitochondrial genome rearrangements have resulted in nearly hundred chromosomes and a systematic dispersal of gene fragments across the multipartite genome. Maturation into functional RNAs involves separate transcription of gene pieces, joining of precursor RNAs via trans-splicing, and RNA editing by substitution and uridine additions both reconstituting crucial coding sequence. How widespread these unusual features are across diplonemids is unclear. We have analyzed the mitochondrial genomes and transcriptomes of four species from the Diplonema/Rhynchopus clade, revealing a considerable genomic plasticity. Although gene breakpoints, and thus the total number of gene pieces (~80), are essentially conserved across this group, the number of distinct chromosomes varies by a factor of two, with certain chromosomes combining up to eight unrelated gene fragments. Several internal protein-coding gene pieces overlap substantially, resulting, for example, in a stretch of 22 identical amino acids in cytochrome c oxidase subunit 1 and NADH dehydrogenase subunit 5. Finally, the variation of post-transcriptional editing patterns across diplonemids indicates compensation of two adverse trends: rapid sequence evolution and loss of genetic information through unequal chromosome segregation.
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Affiliation(s)
- Matus Valach
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.
| | - Sandrine Moreira
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.,Department of Biochemistry and Molecular Biophysics, Columbia University, Hammer Health Science Center, 701 W 168th St, New York, NY, 10031, USA
| | - Steve Hoffmann
- Leipzig University, LIFE - Leipzig Research Center for Civilization Diseases, Haertelstrasse 16-18, Leipzig, D-04107, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Härtelstrasse 16-18, D-04107, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions, and Leipzig Research Center for Civilization Diseases, University Leipzig, D-04107, Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, Inselstrasse 22, D-04103, Leipzig, Germany.,Fraunhofer Institute for Cell Therapy and Immunology, Perlickstrasse 1, D-04103, Leipzig, Germany.,Department of Theoretical Chemistry of the University of Vienna, Währingerstrasse 17, A-1090, Vienna, Austria.,Center for RNA in Technology and Health, University of Copenhagen, Grønnegårdsvej 3, 1870, Frederiksberg C, Denmark.,Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA
| | - Gertraud Burger
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.
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82
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Mitochondrial cytochrome c oxidase: catalysis, coupling and controversies. Biochem Soc Trans 2017; 45:813-829. [PMID: 28620043 DOI: 10.1042/bst20160139] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/07/2017] [Accepted: 04/11/2017] [Indexed: 01/04/2023]
Abstract
Mitochondrial cytochrome c oxidase is a member of a diverse superfamily of haem-copper oxidases. Its mechanism of oxygen reduction is reviewed in terms of the cycle of catalytic intermediates and their likely chemical structures. This reaction cycle is coupled to the translocation of protons across the inner mitochondrial membrane in which it is located. The likely mechanism by which this occurs, derived in significant part from studies of bacterial homologues, is presented. These mechanisms of catalysis and coupling, together with current alternative proposals of underlying mechanisms, are critically reviewed.
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83
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Crystal structure of CO-bound cytochrome c oxidase determined by serial femtosecond X-ray crystallography at room temperature. Proc Natl Acad Sci U S A 2017; 114:8011-8016. [PMID: 28698372 DOI: 10.1073/pnas.1705628114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytochrome c oxidase (CcO), the terminal enzyme in the electron transfer chain, translocates protons across the inner mitochondrial membrane by harnessing the free energy generated by the reduction of oxygen to water. Several redox-coupled proton translocation mechanisms have been proposed, but they lack confirmation, in part from the absence of reliable structural information due to radiation damage artifacts caused by the intense synchrotron radiation. Here we report the room temperature, neutral pH (6.8), damage-free structure of bovine CcO (bCcO) in the carbon monoxide (CO)-bound state at a resolution of 2.3 Å, obtained by serial femtosecond X-ray crystallography (SFX) with an X-ray free electron laser. As a comparison, an equivalent structure was obtained at a resolution of 1.95 Å, from data collected at a synchrotron light source. In the SFX structure, the CO is coordinated to the heme a3 iron atom, with a bent Fe-C-O angle of ∼142°. In contrast, in the synchrotron structure, the Fe-CO bond is cleaved; CO relocates to a new site near CuB, which, in turn, moves closer to the heme a3 iron by ∼0.38 Å. Structural comparison reveals that ligand binding to the heme a3 iron in the SFX structure is associated with an allosteric structural transition, involving partial unwinding of the helix-X between heme a and a3, thereby establishing a communication linkage between the two heme groups, setting the stage for proton translocation during the ensuing redox chemistry.
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84
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Papa S, Capitanio G, Papa F. The mechanism of coupling between oxido-reduction and proton translocation in respiratory chain enzymes. Biol Rev Camb Philos Soc 2017. [DOI: 10.1111/brv.12347] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Sergio Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
- Institute of Biomembranes and Bioenergetics; National Research Council at BMSNSO; Piazza G. Cesare 11 70124 Bari Italy
| | - Giuseppe Capitanio
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
| | - Francesco Papa
- Department of Basic Medical Sciences, Neurosciences and Sense Organs (BMSNSO), Section of Medical Biochemistry; University of Bari ‘Aldo Moro’; Piazza G. Cesare 11 70124 Bari Italy
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85
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Luo F, Shinzawa-Itoh K, Hagimoto K, Shimada A, Shimada S, Yamashita E, Yoshikawa S, Tsukihara T. Structure of bovine cytochrome c oxidase crystallized at a neutral pH using a fluorinated detergent. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2017; 73:416-422. [PMID: 28695851 PMCID: PMC5505247 DOI: 10.1107/s2053230x17008834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/14/2017] [Indexed: 12/24/2022]
Abstract
Although the enzymatic activity of cytochrome c oxidase (CcO) depends sensitively on pH over a wide range, X-ray structure analyses of bovine CcO have been conducted using crystals prepared at pH 5.7 owing to difficulty in crystallizing this protein. Here, oxidized CcO at pH 7.3 was successfully crystallized using a fluorinated octyl-maltoside derivative, and the structure was determined at 1.77 Å resolution. Cytochrome c oxidase (CcO) couples proton pumping to O2 reduction. Its enzymatic activity depends sensitively on pH over a wide range. However, owing to difficulty in crystallizing this protein, X-ray structure analyses of bovine CcO aimed at understanding its reaction mechanism have been conducted using crystals prepared at pH 5.7, which is significantly lower than that in the cell. Here, oxidized CcO at pH 7.3 was crystallized using a fluorinated octyl-maltoside derivative, and the structure was determined at 1.77 Å resolution. No structural differences between crystals obtained at the neutral pH and the acidic pH were detected within the molecules. On the other hand, some differences in intermolecular interactions were detected between the two types of crystal. The influence of pH on the molecular surface is likely to contribute to the pH dependency of the aerobic oxidation of ferrocytochrome c.
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Affiliation(s)
- Fangjia Luo
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Kaede Hagimoto
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Satoru Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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86
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Tissue- and Condition-Specific Isoforms of Mammalian Cytochrome c Oxidase Subunits: From Function to Human Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:1534056. [PMID: 28593021 PMCID: PMC5448071 DOI: 10.1155/2017/1534056] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/29/2017] [Indexed: 01/05/2023]
Abstract
Cytochrome c oxidase (COX) is the terminal enzyme of the electron transport chain and catalyzes the transfer of electrons from cytochrome c to oxygen. COX consists of 14 subunits, three and eleven encoded, respectively, by the mitochondrial and nuclear DNA. Tissue- and condition-specific isoforms have only been reported for COX but not for the other oxidative phosphorylation complexes, suggesting a fundamental requirement to fine-tune and regulate the essentially irreversible reaction catalyzed by COX. This article briefly discusses the assembly of COX in mammals and then reviews the functions of the six nuclear-encoded COX subunits that are expressed as isoforms in specialized tissues including those of the liver, heart and skeletal muscle, lung, and testes: COX IV-1, COX IV-2, NDUFA4, NDUFA4L2, COX VIaL, COX VIaH, COX VIb-1, COX VIb-2, COX VIIaH, COX VIIaL, COX VIIaR, COX VIIIH/L, and COX VIII-3. We propose a model in which the isoforms mediate the interconnected regulation of COX by (1) adjusting basal enzyme activity to mitochondrial capacity of a given tissue; (2) allosteric regulation to adjust energy production to need; (3) altering proton pumping efficiency under certain conditions, contributing to thermogenesis; (4) providing a platform for tissue-specific signaling; (5) stabilizing the COX dimer; and (6) modulating supercomplex formation.
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87
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Magalhães PR, Oliveira ASF, Campos SRR, Soares CM, Baptista AM. Effect of a pH Gradient on the Protonation States of Cytochrome c Oxidase: A Continuum Electrostatics Study. J Chem Inf Model 2017; 57:256-266. [PMID: 28095694 DOI: 10.1021/acs.jcim.6b00575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytochrome c oxidase (CcO) couples the reduction of dioxygen to water with transmembrane proton pumping, which leads to the generation of an electrochemical gradient. In this study we analyze how one of the components of the electrochemical gradient, the difference in pH across the membrane, or ΔpH, influences the protonation states of residues in CcO. We modified our continuum electrostatics/Monte Carlo (CE/MC) method in order to include the ΔpH and applied it to the study of CcO, in what is, to our best knowledge, the first CE/MC study of CcO in the presence of a pH gradient. The inclusion of a transmembrane pH gradient allows for the identification of residues whose titration behavior depends on the pH on both sides of the membrane. Among the several residues with unusual titration profiles, three are well-known key residues in the proton transfer process of CcO: E286I, Y288I, and K362I. All three residues have been previously identified as being critical for the catalytic or proton pumping functions of CcO. Our results suggest that when the pH gradient increases, these residues may be part of a regulatory mechanism to stem the proton flow.
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Affiliation(s)
- Pedro R Magalhães
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa , 2781-901 Oeiras, Portugal
| | - A Sofia F Oliveira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa , 2781-901 Oeiras, Portugal
| | - Sara R R Campos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa , 2781-901 Oeiras, Portugal
| | - Cláudio M Soares
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa , 2781-901 Oeiras, Portugal
| | - António M Baptista
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa , 2781-901 Oeiras, Portugal
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88
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Avilés-Moreno JR, Berden G, Oomens J, Martínez-Haya B. Isolated complexes of the amino acid arginine with polyether and polyamine macrocycles, the role of proton transfer. Phys Chem Chem Phys 2017; 19:31345-31351. [DOI: 10.1039/c7cp04270a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protonated arginine interacts with 12-crown-4 through the guanidinium side group. In the complex with the N-substituted analog cyclen, the dominant conformation is the result of the proton transfer from the carboxylic acid group of the amino acid to the macrocycle.
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Affiliation(s)
- Juan Ramón Avilés-Moreno
- Department of Physical
- Chemical and Natural Systems
- Universidad Pablo de Olavide
- E-41013 Seville
- Spain
| | - Giel Berden
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525ED Nijmegen
- The Netherlands
| | - Jos Oomens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525ED Nijmegen
- The Netherlands
| | - Bruno Martínez-Haya
- Department of Physical
- Chemical and Natural Systems
- Universidad Pablo de Olavide
- E-41013 Seville
- Spain
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89
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Amazing structure of respirasome: unveiling the secrets of cell respiration. Protein Cell 2016; 7:854-865. [PMID: 27743346 PMCID: PMC5205662 DOI: 10.1007/s13238-016-0329-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 09/28/2016] [Indexed: 11/02/2022] Open
Abstract
Respirasome, a huge molecular machine that carries out cellular respiration, has gained growing attention since its discovery, because respiration is the most indispensable biological process in almost all living creatures. The concept of respirasome has renewed our understanding of the respiratory chain organization, and most recently, the structure of respirasome solved by Yang's group from Tsinghua University (Gu et al. Nature 237(7622):639-643, 2016) firstly presented the detailed interactions within this huge molecular machine, and provided important information for drug design and screening. However, the study of cellular respiration went through a long history. Here, we briefly showed the detoured history of respiratory chain investigation, and then described the amazing structure of respirasome.
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90
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Pentinsaari M, Salmela H, Mutanen M, Roslin T. Molecular evolution of a widely-adopted taxonomic marker (COI) across the animal tree of life. Sci Rep 2016; 6:35275. [PMID: 27734964 PMCID: PMC5062346 DOI: 10.1038/srep35275] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/15/2016] [Indexed: 11/28/2022] Open
Abstract
DNA barcodes are widely used for identification and discovery of species. While such use draws on information at the DNA level, the current amassment of ca. 4.7 million COI barcodes also offers a unique resource for exploring functional constraints on DNA evolution. Here, we explore amino acid variation in a crosscut of the entire animal kingdom. Patterns of DNA variation were linked to functional constraints at the level of the amino acid sequence in functionally important parts of the enzyme. Six amino acid sites show variation with possible effects on enzyme function. Overall, patterns of amino acid variation suggest convergent or parallel evolution at the protein level connected to the transition into a parasitic life style. Denser sampling of two diverse insect taxa revealed that the beetles (Coleoptera) show more amino acid variation than the butterflies and moths (Lepidoptera), indicating fundamental difference in patterns of molecular evolution in COI. Several amino acid sites were found to be under notably strong purifying selection in Lepidoptera as compared to Coleoptera. Overall, these findings demonstrate the utility of the global DNA barcode library to extend far beyond identification and taxonomy, and will hopefully be followed by a multitude of work.
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Affiliation(s)
- Mikko Pentinsaari
- Department of Genetics and Physiology, University of Oulu, P.O.Box 3000 (Pentti Kaiteran katu 1), FI-90014, Finland
| | - Heli Salmela
- Department of Biosciences, Centre of Excellence in Biological Interactions, University of Helsinki, Viikinkaari 1, FI-00014, Finland
| | - Marko Mutanen
- Department of Genetics and Physiology, University of Oulu, P.O.Box 3000 (Pentti Kaiteran katu 1), FI-90014, Finland
| | - Tomas Roslin
- Spatial Foodweb Ecology Group, Department of Agricultural Sciences, University of Helsinki, Latokartanonkaari 5, FI-00014, Finland
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 750 07 Uppsala, Sweden
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91
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Mahapatra G, Varughese A, Ji Q, Lee I, Liu J, Vaishnav A, Sinkler C, Kapralov AA, Moraes CT, Sanderson TH, Stemmler TL, Grossman LI, Kagan VE, Brunzelle JS, Salomon AR, Edwards BFP, Hüttemann M. Phosphorylation of Cytochrome c Threonine 28 Regulates Electron Transport Chain Activity in Kidney: IMPLICATIONS FOR AMP KINASE. J Biol Chem 2016; 292:64-79. [PMID: 27758862 DOI: 10.1074/jbc.m116.744664] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/20/2016] [Indexed: 11/06/2022] Open
Abstract
Mammalian cytochrome c (Cytc) plays a key role in cellular life and death decisions, functioning as an electron carrier in the electron transport chain and as a trigger of apoptosis when released from the mitochondria. However, its regulation is not well understood. We show that the major fraction of Cytc isolated from kidneys is phosphorylated on Thr28, leading to a partial inhibition of respiration in the reaction with cytochrome c oxidase. To further study the effect of Cytc phosphorylation in vitro, we generated T28E phosphomimetic Cytc, revealing superior behavior regarding protein stability and its ability to degrade reactive oxygen species compared with wild-type unphosphorylated Cytc Introduction of T28E phosphomimetic Cytc into Cytc knock-out cells shows that intact cell respiration, mitochondrial membrane potential (ΔΨm), and ROS levels are reduced compared with wild type. As we show by high resolution crystallography of wild-type and T28E Cytc in combination with molecular dynamics simulations, Thr28 is located at a central position near the heme crevice, the most flexible epitope of the protein apart from the N and C termini. Finally, in silico prediction and our experimental data suggest that AMP kinase, which phosphorylates Cytc on Thr28 in vitro and colocalizes with Cytc to the mitochondrial intermembrane space in the kidney, is the most likely candidate to phosphorylate Thr28 in vivo We conclude that Cytc phosphorylation is mediated in a tissue-specific manner and leads to regulation of electron transport chain flux via "controlled respiration," preventing ΔΨm hyperpolarization, a known cause of ROS and trigger of apoptosis.
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Affiliation(s)
- Gargi Mahapatra
- From the Center for Molecular Medicine and Genetics and.,the Departments of Biochemistry and Molecular Biology
| | - Ashwathy Varughese
- From the Center for Molecular Medicine and Genetics and.,the Departments of Biochemistry and Molecular Biology
| | | | - Icksoo Lee
- From the Center for Molecular Medicine and Genetics and.,the College of Medicine, Dankook University, Cheonan-si, Chungcheongnam-do 31116, Republic of Korea
| | - Jenney Liu
- From the Center for Molecular Medicine and Genetics and
| | | | | | - Alexandr A Kapralov
- the Center for Free Radical and Antioxidant Health and the Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Carlos T Moraes
- the Department of Neurology, University of Miami School of Medicine, Miami, Florida 33136, and
| | | | - Timothy L Stemmler
- Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201
| | | | - Valerian E Kagan
- the Center for Free Radical and Antioxidant Health and the Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Joseph S Brunzelle
- the Life Sciences Collaborative Access Team, Northwestern University, Center for Synchrotron Research, Argonne, Illinois 60439
| | - Arthur R Salomon
- the MCB Department, Brown University, Providence, Rhode Island 02912
| | | | - Maik Hüttemann
- From the Center for Molecular Medicine and Genetics and .,the Departments of Biochemistry and Molecular Biology
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92
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Letts JA, Fiedorczuk K, Sazanov LA. The architecture of respiratory supercomplexes. Nature 2016; 537:644-648. [PMID: 27654913 DOI: 10.1038/nature19774] [Citation(s) in RCA: 367] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 08/18/2016] [Indexed: 02/06/2023]
Abstract
Mitochondrial electron transport chain complexes are organized into supercomplexes responsible for carrying out cellular respiration. Here we present three architectures of mammalian (ovine) supercomplexes determined by cryo-electron microscopy. We identify two distinct arrangements of supercomplex CICIII2CIV (the respirasome)-a major 'tight' form and a minor 'loose' form (resolved at the resolution of 5.8 Å and 6.7 Å, respectively), which may represent different stages in supercomplex assembly or disassembly. We have also determined an architecture of supercomplex CICIII2 at 7.8 Å resolution. All observed density can be attributed to the known 80 subunits of the individual complexes, including 132 transmembrane helices. The individual complexes form tight interactions that vary between the architectures, with complex IV subunit COX7a switching contact from complex III to complex I. The arrangement of active sites within the supercomplex may help control reactive oxygen species production. To our knowledge, these are the first complete architectures of the dominant, physiologically relevant state of the electron transport chain.
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Affiliation(s)
- James A Letts
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Karol Fiedorczuk
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria.,MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, UK
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
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93
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Yano N, Muramoto K, Shimada A, Takemura S, Baba J, Fujisawa H, Mochizuki M, Shinzawa-Itoh K, Yamashita E, Tsukihara T, Yoshikawa S. The Mg2+-containing Water Cluster of Mammalian Cytochrome c Oxidase Collects Four Pumping Proton Equivalents in Each Catalytic Cycle. J Biol Chem 2016; 291:23882-23894. [PMID: 27605664 DOI: 10.1074/jbc.m115.711770] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 08/26/2016] [Indexed: 11/06/2022] Open
Abstract
Bovine heart cytochrome c oxidase (CcO) pumps four proton equivalents per catalytic cycle through the H-pathway, a proton-conducting pathway, which includes a hydrogen bond network and a water channel operating in tandem. Protons are transferred by H3O+ through the water channel from the N-side into the hydrogen bond network, where they are pumped to the P-side by electrostatic repulsion between protons and net positive charges created at heme a as a result of electron donation to O2 bound to heme a3 To block backward proton movement, the water channel remains closed after O2 binding until the sequential four-proton pumping process is complete. Thus, the hydrogen bond network must collect four proton equivalents before O2 binding. However, a region with the capacity to accept four proton equivalents was not discernable in the x-ray structures of the hydrogen bond network. The present x-ray structures of oxidized/reduced bovine CcO are improved from 1.8/1.9 to 1.5/1.6 Å resolution, increasing the structural information by 1.7/1.6 times and revealing that a large water cluster, which includes a Mg2+ ion, is linked to the H-pathway. The cluster contains enough proton acceptor groups to retain four proton equivalents. The redox-coupled x-ray structural changes in Glu198, which bridges the Mg2+ and CuA (the initial electron acceptor from cytochrome c) sites, suggest that the CuA-Glu198-Mg2+ system drives redox-coupled transfer of protons pooled in the water cluster to the H-pathway. Thus, these x-ray structures indicate that the Mg2+-containing water cluster is the crucial structural element providing the effective proton pumping in bovine CcO.
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Affiliation(s)
| | - Kazumasa Muramoto
- the Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akoh, Hyogo 678-1297
| | | | | | | | | | | | | | - Eiki Yamashita
- the Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, and
| | - Tomitake Tsukihara
- From the Picobiology Institute and.,the Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, and.,JSJT, CREST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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94
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Yang L, Skjevik ÅA, Han Du WG, Noodleman L, Walker RC, Götz AW. Water exit pathways and proton pumping mechanism in B-type cytochrome c oxidase from molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:1594-1606. [PMID: 27317965 PMCID: PMC4995112 DOI: 10.1016/j.bbabio.2016.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/21/2016] [Accepted: 06/14/2016] [Indexed: 01/22/2023]
Abstract
Cytochrome c oxidase (CcO) is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. While proton uptake channels as well as water exit channels have been identified for A-type CcOs, the means by which water and protons exit B-type CcOs remain unclear. In this work, we investigate potential mechanisms for proton transport above the dinuclear center (DNC) in ba3-type CcO of Thermus thermophilus. Using long-time scale, all-atom molecular dynamics (MD) simulations for several relevant protonation states, we identify a potential mechanism for proton transport that involves propionate A of the active site heme a3 and residues Asp372, His376 and Glu126(II), with residue His376 acting as the proton-loading site. The proposed proton transport process involves a rotation of residue His376 and is in line with experimental findings. We also demonstrate how the strength of the salt bridge between residues Arg225 and Asp287 depends on the protonation state and that this salt bridge is unlikely to act as a simple electrostatic gate that prevents proton backflow. We identify two water exit pathways that connect the water pool above the DNC to the outer P-side of the membrane, which can potentially also act as proton exit transport pathways. Importantly, these water exit pathways can be blocked by narrowing the entrance channel between residues Gln151(II) and Arg449/Arg450 or by obstructing the entrance through a conformational change of residue Tyr136, respectively, both of which seem to be affected by protonation of residue His376.
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Affiliation(s)
- Longhua Yang
- Department of Chemistry, Nanchang University, 999 Xuefudadao, Nanchang, Jiangxi 330031, China; San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Drive MC0505, La Jolla, CA 92093, USA
| | - Åge A Skjevik
- San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Drive MC0505, La Jolla, CA 92093, USA; Department of Biomedicine, University of Bergen, N-5009 Bergen, Norway
| | - Wen-Ge Han Du
- Department of Integrative Structural and Computational Biology, GAC1118, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Louis Noodleman
- Department of Integrative Structural and Computational Biology, GAC1118, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ross C Walker
- San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Drive MC0505, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Andreas W Götz
- San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Drive MC0505, La Jolla, CA 92093, USA.
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95
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Supekar S, Gamiz-Hernandez AP, Kaila VRI. A Protonated Water Cluster as a Transient Proton-Loading Site in Cytochrome cOxidase. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Shreyas Supekar
- Department Chemie; Technische Universität München (TUM); Lichtenbergstraße 4 85747 Garching Germany
| | - Ana P. Gamiz-Hernandez
- Department Chemie; Technische Universität München (TUM); Lichtenbergstraße 4 85747 Garching Germany
| | - Ville R. I. Kaila
- Department Chemie; Technische Universität München (TUM); Lichtenbergstraße 4 85747 Garching Germany
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96
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Supekar S, Gamiz-Hernandez AP, Kaila VRI. A Protonated Water Cluster as a Transient Proton-Loading Site in Cytochrome c Oxidase. Angew Chem Int Ed Engl 2016; 55:11940-4. [PMID: 27539738 DOI: 10.1002/anie.201603606] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/07/2016] [Indexed: 01/11/2023]
Abstract
Cytochrome c oxidase (CcO) is a redox-driven proton pump that powers aerobic respiratory chains. We show here by multi-scale molecular simulations that a protonated water cluster near the active site is likely to serve as the transient proton-loading site (PLS) that stores a proton during the pumping process. The pKa of this water cluster is sensitive to the redox states of the enzyme, showing distinct similarities to other energy converting proton pumps.
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Affiliation(s)
- Shreyas Supekar
- Department Chemie, Technische Universität München (TUM), Lichtenbergstraße 4, 85747, Garching, Germany
| | - Ana P Gamiz-Hernandez
- Department Chemie, Technische Universität München (TUM), Lichtenbergstraße 4, 85747, Garching, Germany
| | - Ville R I Kaila
- Department Chemie, Technische Universität München (TUM), Lichtenbergstraße 4, 85747, Garching, Germany.
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97
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Shelar A, Bansal M. Helix perturbations in membrane proteins assist in inter-helical interactions and optimal helix positioning in the bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2804-2817. [PMID: 27521749 DOI: 10.1016/j.bbamem.2016.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/13/2016] [Accepted: 08/07/2016] [Indexed: 12/11/2022]
Abstract
Transmembrane (TM) helices in integral membrane proteins are primarily α-helical in structure. Here we analyze 1134 TM helices in 90 high resolution membrane proteins and find that apart from the widely prevalent α-helices, TM regions also contain stretches of 310 (3 to 8 residues) and π-helices (5 to 19 residues) with distinct sequence signatures. The various helix perturbations in TM regions comprise of helices with kinked geometry, as well as those with an interspersed 310/π-helical fragment and show high occurrence in a few membrane proteins. Proline is frequently present at sites of these perturbations, but it is neither a necessary nor a sufficient requirement. Helix perturbations are also conserved within a family of membrane proteins despite low sequence identity in the perturbed region. Furthermore, a perturbation influences the geometry of the TM helix, mediates inter-helical interactions within and across protein chains and avoids hydrophobic mismatch of the helix termini with the bilayer. An analysis of π-helices in the TM regions of the heme copper oxidase superfamily shows that interspersed π-helices can vary in length from 6 to 19 amino acids or be entirely absent, depending upon the protein function. The results presented here would be helpful for prediction of 310 and π-helices in TM regions and can assist the computational design of membrane proteins.
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Affiliation(s)
- Ashish Shelar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Manju Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India.
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98
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Abstract
Like most bacteria, Escherichia coli has a flexible and branched respiratory chain that enables the prokaryote to live under a variety of environmental conditions, from highly aerobic to completely anaerobic. In general, the bacterial respiratory chain is composed of dehydrogenases, a quinone pool, and reductases. Substrate-specific dehydrogenases transfer reducing equivalents from various donor substrates (NADH, succinate, glycerophosphate, formate, hydrogen, pyruvate, and lactate) to a quinone pool (menaquinone, ubiquinone, and dimethylmenoquinone). Then electrons from reduced quinones (quinols) are transferred by terminal reductases to different electron acceptors. Under aerobic growth conditions, the terminal electron acceptor is molecular oxygen. A transfer of electrons from quinol to O₂ is served by two major oxidoreductases (oxidases), cytochrome bo₃ encoded by cyoABCDE and cytochrome bd encoded by cydABX. Terminal oxidases of aerobic respiratory chains of bacteria, which use O₂ as the final electron acceptor, can oxidize one of two alternative electron donors, either cytochrome c or quinol. This review compares the effects of different inhibitors on the respiratory activities of cytochrome bo₃ and cytochrome bd in E. coli. It also presents a discussion on the genetics and the prosthetic groups of cytochrome bo₃ and cytochrome bd. The E. coli membrane contains three types of quinones that all have an octaprenyl side chain (C₄₀). It has been proposed that the bo₃ oxidase can have two ubiquinone-binding sites with different affinities. "WHAT'S NEW" IN THE REVISED ARTICLE: The revised article comprises additional information about subunit composition of cytochrome bd and its role in bacterial resistance to nitrosative and oxidative stresses. Also, we present the novel data on the electrogenic function of appBCX-encoded cytochrome bd-II, a second bd-type oxidase that had been thought not to contribute to generation of a proton motive force in E. coli, although its spectral properties closely resemble those of cydABX-encoded cytochrome bd.
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99
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Dimer interface of bovine cytochrome c oxidase is influenced by local posttranslational modifications and lipid binding. Proc Natl Acad Sci U S A 2016; 113:8230-5. [PMID: 27364008 DOI: 10.1073/pnas.1600354113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bovine cytochrome c oxidase is an integral membrane protein complex comprising 13 protein subunits and associated lipids. Dimerization of the complex has been proposed; however, definitive evidence for the dimer is lacking. We used advanced mass spectrometry methods to investigate the oligomeric state of cytochrome c oxidase and the potential role of lipids and posttranslational modifications in its subunit interfaces. Mass spectrometry of the intact protein complex revealed that both the monomer and the dimer are stabilized by large lipid entities. We identified these lipid species from the purified protein complex, thus implying that they interact specifically with the enzyme. We further identified phosphorylation and acetylation sites of cytochrome c oxidase, located in the peripheral subunits and in the dimer interface, respectively. Comparing our phosphorylation and acetylation sites with those found in previous studies of bovine, mouse, rat, and human cytochrome c oxidase, we found that whereas some acetylation sites within the dimer interface are conserved, suggesting a role for regulation and stabilization of the dimer, phosphorylation sites were less conserved and more transient. Our results therefore provide insights into the locations and interactions of lipids with acetylated residues within the dimer interface of this enzyme, and thereby contribute to a better understanding of its structure in the natural membrane. Moreover dimeric cytochrome c oxidase, comprising 20 transmembrane, six extramembrane subunits, and associated lipids, represents the largest integral membrane protein complex that has been transferred via electrospray intact into the gas phase of a mass spectrometer, representing a significant technological advance.
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100
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Buhlman LM. Parkin loss-of-function pathology: Premature neuronal senescence induced by high levels of reactive oxygen species? Mech Ageing Dev 2016; 161:112-120. [PMID: 27374431 DOI: 10.1016/j.mad.2016.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 12/18/2022]
Abstract
Parkinson's and Alzheimer's diseases (PD and AD, respectively) are considered to be diseases of advanced brain ageing, which seems to involve high levels of reactive oxygen species (ROS). AD neurodegeneration is initially apparent in the hippocampus; as AD progresses, many more brain regions are affected. PD-associated neurodegeneration is relatively limited to dopaminergic neurons of the substantia nigra pars compacta (SNpc), especially in cases in which patients inherit particular disease-causing mutations. Thus, the task of elucidating mechanisms by which loss of function of one particular protein triggers death of a subset of neurons may be more approachable. Understanding the mechanisms of neurodegeneration in these forms of PD may not only shed light on avenues leading toward therapeutic strategies in PD and other neurodegenerative diseases, but also on those leading toward understanding natural ageing. Neurodegeneration in PD patients harboring homozygous loss-of-function mutations in the PARK2 gene may result from unbalanced levels of ROS, which are mostly produced in mitochondria and can irreparably damage macromolecules and trigger apoptosis. This review discusses mitochondrial sources of ROS, how ROS can trigger apoptosis, mechanisms by which Parkin loss-of-function may cause neurodegeneration by increasing ROS levels, and concludes with hypotheses regarding selective SNpc dopaminergic neuron vulnerability.
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Affiliation(s)
- Lori M Buhlman
- Midwestern University, 19555 N 59th Avenue, Glendale, AZ, 85308, USA.
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