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Sindhu T, Debnath P. Cytochrome bc1-aa3 oxidase supercomplex as emerging and potential drug target against tuberculosis. Curr Mol Pharmacol 2021; 15:380-392. [PMID: 34602044 DOI: 10.2174/1874467214666210928152512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/26/2021] [Accepted: 06/06/2021] [Indexed: 11/22/2022]
Abstract
The cytochrome bc1-aa3 supercomplex plays an essential role in the cellular respiratory system of Mycobacterium Tuberculosis. It transfers electrons from menaquinol to cytochrome aa3 (Complex IV) via cytochrome bc1 (Complex III), which reduces the oxygen. The electron transfer from a variety of donors into oxygen through the respiratory electron transport chain is essential to pump protons across the membrane creating an electrochemical transmembrane gradient (proton motive force, PMF) that regulates the synthesis of ATP via the oxidative phosphorylation process. Cytochrome bc1-aa3 supercomplex in M. tuberculosis is, therefore, a major drug target for antibiotic action. In recent years, several respiratory chain components have been targeted for developing new candidate drugs, illustrating the therapeutic potential of obstructing energy conversion of M. tuberculosis. The recently available cryo-EM structure of mycobacterial cytochrome bc1-aa3 supercomplex with open and closed conformations has opened new avenues for understanding its structure and function for developing more effective, new therapeutics against pulmonary tuberculosis. In this review, we discuss the role and function of several components, subunits, and drug targeting elements of the supercomplex cytochrome bc1-aa3, and its potential inhibitors in detail.
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Affiliation(s)
- Thangaraj Sindhu
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
| | - Pal Debnath
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka. India
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2
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Shimada A, Kubo M, Baba S, Yamashita K, Hirata K, Ueno G, Nomura T, Kimura T, Shinzawa-Itoh K, Baba J, Hatano K, Eto Y, Miyamoto A, Murakami H, Kumasaka T, Owada S, Tono K, Yabashi M, Yamaguchi Y, Yanagisawa S, Sakaguchi M, Ogura T, Komiya R, Yan J, Yamashita E, Yamamoto M, Ago H, Yoshikawa S, Tsukihara T. A nanosecond time-resolved XFEL analysis of structural changes associated with CO release from cytochrome c oxidase. SCIENCE ADVANCES 2017; 3:e1603042. [PMID: 28740863 PMCID: PMC5510965 DOI: 10.1126/sciadv.1603042] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 06/14/2017] [Indexed: 05/21/2023]
Abstract
Bovine cytochrome c oxidase (CcO), a 420-kDa membrane protein, pumps protons using electrostatic repulsion between protons transferred through a water channel and net positive charges created by oxidation of heme a (Fe a ) for reduction of O2 at heme a3 (Fe a3). For this process to function properly, timing is essential: The channel must be closed after collection of the protons to be pumped and before Fe a oxidation. If the channel were to remain open, spontaneous backflow of the collected protons would occur. For elucidation of the channel closure mechanism, the opening of the channel, which occurs upon release of CO from CcO, is investigated by newly developed time-resolved x-ray free-electron laser and infrared techniques with nanosecond time resolution. The opening process indicates that CuB senses completion of proton collection and binds O2 before binding to Fe a3 to close the water channel using a conformational relay system, which includes CuB, heme a3, and a transmembrane helix, to block backflow of the collected protons.
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Affiliation(s)
- Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Minoru Kubo
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Seiki Baba
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Keitaro Yamashita
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kunio Hirata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Go Ueno
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Takashi Nomura
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Tetsunari Kimura
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Junpei Baba
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Keita Hatano
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Yuki Eto
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Akari Miyamoto
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hironori Murakami
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Takashi Kumasaka
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Makina Yabashi
- Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yoshihiro Yamaguchi
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Sachiko Yanagisawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Miyuki Sakaguchi
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Takashi Ogura
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Ryo Komiya
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Jiwang Yan
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masaki Yamamoto
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Hideo Ago
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Corresponding author. (T.T.); (S.Y.); (H.A.)
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- Corresponding author. (T.T.); (S.Y.); (H.A.)
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (CREST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Corresponding author. (T.T.); (S.Y.); (H.A.)
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3
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Shimada S, Shinzawa-Itoh K, Baba J, Aoe S, Shimada A, Yamashita E, Kang J, Tateno M, Yoshikawa S, Tsukihara T. Complex structure of cytochrome c-cytochrome c oxidase reveals a novel protein-protein interaction mode. EMBO J 2016; 36:291-300. [PMID: 27979921 PMCID: PMC5286356 DOI: 10.15252/embj.201695021] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 10/21/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial cytochrome c oxidase (CcO) transfers electrons from cytochrome c (Cyt.c) to O2 to generate H2O, a process coupled to proton pumping. To elucidate the mechanism of electron transfer, we determined the structure of the mammalian Cyt.c–CcO complex at 2.0‐Å resolution and identified an electron transfer pathway from Cyt.c to CcO. The specific interaction between Cyt.c and CcO is stabilized by a few electrostatic interactions between side chains within a small contact surface area. Between the two proteins are three water layers with a long inter‐molecular span, one of which lies between the other two layers without significant direct interaction with either protein. Cyt.c undergoes large structural fluctuations, using the interacting regions with CcO as a fulcrum. These features of the protein–protein interaction at the docking interface represent the first known example of a new class of protein–protein interaction, which we term “soft and specific”. This interaction is likely to contribute to the rapid association/dissociation of the Cyt.c–CcO complex, which facilitates the sequential supply of four electrons for the O2 reduction reaction.
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Affiliation(s)
- Satoru Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Junpei Baba
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Shimpei Aoe
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Jiyoung Kang
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Masaru Tateno
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan .,Institute for Protein Research, Osaka University, Suita, Osaka, Japan.,JST, CREST, Kawaguchi, Saitama, Japan
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4
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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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5
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Yano N, Muramoto K, Mochizuki M, Shinzawa-Itoh K, Yamashita E, Yoshikawa S, Tsukihara T. X-ray structure of cyanide-bound bovine heart cytochrome c oxidase in the fully oxidized state at 2.0 Å resolution. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2015; 71:726-30. [PMID: 26057802 DOI: 10.1107/s2053230x15007025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/08/2015] [Indexed: 11/10/2022]
Abstract
The X-ray structure of cyanide-bound bovine heart cytochrome c oxidase in the fully oxidized state was determined at 2.0 Å resolution. The structure reveals that the peroxide that bridges the two metals in the fully oxidized state is replaced by a cyanide ion bound in a nearly symmetric end-on fashion without significantly changing the protein conformation outside the two metal sites.
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Affiliation(s)
- Naomine Yano
- Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Tokai, Ibaraki, Japan
| | - Kazumasa Muramoto
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Japan
| | - Masao Mochizuki
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Japan
| | - Kyoko Shinzawa-Itoh
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Shinya Yoshikawa
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Japan
| | - Tomitake Tsukihara
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Kamigori-cho, Japan
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6
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Suga M, Maeda S, Nakagawa S, Yamashita E, Tsukihara T. A description of the structural determination procedures of a gap junction channel at 3.5 A resolution. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:758-66. [PMID: 19622859 PMCID: PMC2714718 DOI: 10.1107/s0907444909014711] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Accepted: 04/20/2009] [Indexed: 11/10/2022]
Abstract
Intercellular signalling is an essential characteristic of multicellular organisms. Gap junctions, which consist of arrays of intercellular channels, permit the exchange of ions and small molecules between adjacent cells. Here, the structural determination of a gap junction channel composed of connexin 26 (Cx26) at 3.5 A resolution is described. During each step of the purification process, the protein was examined using electron microscopy and/or dynamic light scattering. Dehydration of the crystals improved the resolution limits. Phase refinement using multi-crystal averaging in conjunction with noncrystallographic symmetry averaging based on strictly determined noncrystallographic symmetry operators resulted in an electron-density map for model building. The amino-acid sequence of a protomer structure consisting of the amino-terminal helix, four transmembrane helices and two extracellular loops was assigned to the electron-density map. The amino-acid assignment was confirmed using six selenomethionine (SeMet) sites in the difference Fourier map of the SeMet derivative and three intramolecular disulfide bonds in the anomalous difference Fourier map of the native crystal.
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Affiliation(s)
- Michihiro Suga
- Institute for Protein Research, Osaka University, OLABB, 6-2-6 Furuedai, Suita, Osaka 565-0874, Japan
| | - Shoji Maeda
- Institute for Protein Research, Osaka University, OLABB, 6-2-6 Furuedai, Suita, Osaka 565-0874, Japan
| | - So Nakagawa
- Institute for Protein Research, Osaka University, OLABB, 6-2-6 Furuedai, Suita, Osaka 565-0874, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, OLABB, 6-2-6 Furuedai, Suita, Osaka 565-0874, Japan
| | - Tomitake Tsukihara
- Institute for Protein Research, Osaka University, OLABB, 6-2-6 Furuedai, Suita, Osaka 565-0874, Japan
- Department of Life Science, University of Hyogo, Kamigohori, Akoh, Hyogo 678-1297, Japan
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Hart SE, Howe CJ, Mizuguchi K, Fernandez-Recio J. Docking of cytochrome c6 and plastocyanin to the aa3-type cytochrome c oxidase in the cyanobacterium Phormidium laminosum. Protein Eng Des Sel 2008; 21:689-98. [DOI: 10.1093/protein/gzn051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Mitochondrial genome analysis of Ochotona curzoniae and implication of cytochrome c oxidase in hypoxic adaptation. Mitochondrion 2008; 8:352-7. [PMID: 18722554 DOI: 10.1016/j.mito.2008.07.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/16/2008] [Accepted: 07/21/2008] [Indexed: 11/20/2022]
Abstract
Pikas originated in Asia and are small lagomorphs native to cold climates. The plateau pika, Ochotona curzoniae is a keystone species on the Qinghai-Tibet Plateau and an ideal animal model for hypoxic adaptation studies. Altered mitochondrial function, especially cytochrome c oxidase activity, is an important factor in modulation of energy generation and expenditure during cold and hypoxia adaptation. In this study, we determined the complete nucleotide sequence of the O. curzoniae mitochondrial genome. The plateau pika mitochondrial DNA is 17,131bp long and encodes the complete set of 37 proteins typical for vertebrates. Phylogenetic analysis based on concatenated heavy-strand encoded protein-coding genes revealed that pikas are closer to rabbit and hare than to rat. This suggests that rabbit or hare would be a good control animal for pikas in cold and hypoxia adaptation studies. Fifteen novel mitochondrial DNA-encoded amino acid changes were identified in the pikas, including three in the subunits of cytochrome c oxidase. These amino acid substitutions potentially function in modulation of mitochondrial complexes and electron transport efficiency during cold and hypoxia adaptation.
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Woody RW. Heme-heme interactions in tetramers and dimers of hemoglobin subunits: DeVoe theory calculations. Chirality 2005; 17:450-5. [PMID: 16096988 DOI: 10.1002/chir.20192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Detectable exciton couplets arising from heme-heme interactions in the hemoglobin (Hb) tetramers of HbO(2) and deoxyHb were predicted by DeVoe theory. This prediction was supported by the observation of an exciton couplet in the CD difference spectrum between the Hb tetramer and the alphabeta dimer of HbCO. In this paper, DeVoe theory is used to calculate the heme-heme interactions in the CO complex of the Hb tetramer (alpha(2)beta(2)) and dimer (alphabeta), the systems studied by Goldbeck et al. The couplet strength of the resulting theoretical CD difference spectrum agrees well with experiment, thus confirming that heme-heme interactions contribute significantly to the CD of HbCO. Given that the heme-heme distances in HbCO are 25 A and more, it is highly likely that heme-heme interactions also contribute significantly to the CD of other multi-heme proteins, e.g., cytochrome c(3), cytochrome oxidase, cytochrome bc(1), etc., where the hemes are in closer proximity.
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Affiliation(s)
- Robert W Woody
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA.
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10
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Eubel H, Jänsch L, Braun HP. New insights into the respiratory chain of plant mitochondria. Supercomplexes and a unique composition of complex II. PLANT PHYSIOLOGY 2003; 133:274-86. [PMID: 12970493 PMCID: PMC196604 DOI: 10.1104/pp.103.024620] [Citation(s) in RCA: 245] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2003] [Revised: 04/22/2003] [Accepted: 05/27/2003] [Indexed: 05/18/2023]
Abstract
A project to systematically investigate respiratory supercomplexes in plant mitochondria was initiated. Mitochondrial fractions from Arabidopsis, potato (Solanum tuberosum), bean (Phaseolus vulgaris), and barley (Hordeum vulgare) were carefully treated with various concentrations of the nonionic detergents dodecylmaltoside, Triton X-100, or digitonin, and proteins were subsequently separated by (a) Blue-native polyacrylamide gel electrophoresis (PAGE), (b) two-dimensional Blue-native/sodium dodecyl sulfate-PAGE, and (c) two-dimensional Blue-native/Blue-native PAGE. Three high molecular mass complexes of 1,100, 1,500, and 3,000 kD are visible on one-dimensional Blue native gels, which were identified by separations on second gel dimensions and protein analyses by mass spectrometry. The 1,100-kD complex represents dimeric ATP synthase and is only stable under very low concentrations of detergents. In contrast, the 1,500-kD complex is stable at medium and even high concentrations of detergents and includes the complexes I and III(2). Depending on the investigated organism, 50% to 90% of complex I forms part of this supercomplex if solubilized with digitonin. The 3,000-kD complex, which also includes the complexes I and III, is of low abundance and most likely has a III(4)I(2) structure. The complexes IV, II, and the alternative oxidase were not part of supercomplexes under all conditions applied. Digitonin proved to be the ideal detergent for supercomplex stabilization and also allows optimal visualization of the complexes II and IV on Blue-native gels. Complex II unexpectedly was found to be composed of seven subunits, and complex IV is present in two different forms on the Blue-native gels, the larger of which comprises additional subunits including a 32-kD protein resembling COX VIb from other organisms. We speculate that supercomplex formation between the complexes I and III limits access of alternative oxidase to its substrate ubiquinol and possibly regulates alternative respiration. The data of this investigation are available at http://www.gartenbau.uni-hannover.de/genetik/braun/AMPP.
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Affiliation(s)
- Holger Eubel
- Institut für Angewandte Genetik, Universität Hannover, Herrenhäuser Strasse 2, D-30419 Hannover, Germany
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11
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Berry S. Endosymbiosis and the design of eukaryotic electron transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2003; 1606:57-72. [PMID: 14507427 DOI: 10.1016/s0005-2728(03)00084-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The bioenergetic organelles of eukaryotic cells, mitochondria and chloroplasts, are derived from endosymbiotic bacteria. Their electron transport chains (ETCs) resemble those of free-living bacteria, but were tailored for energy transformation within the host cell. Parallel evolutionary processes in mitochondria and chloroplasts include reductive as well as expansive events: On one hand, bacterial complexes were lost in eukaryotes with a concomitant loss of metabolic flexibility. On the other hand, new subunits have been added to the remaining bacterial complexes, new complexes have been introduced, and elaborate folding patterns of the thylakoid and mitochondrial inner membranes have emerged. Some bacterial pathways were reinvented independently by eukaryotes, such as parallel routes for quinol oxidation or the use of various anaerobic electron acceptors. Multicellular organization and ontogenetic cycles in eukaryotes gave rise to further modifications of the bioenergetic organelles. Besides mitochondria and chloroplasts, eukaryotes have ETCs in other membranes, such as the plasma membrane (PM) redox system, or the cytochrome P450 (CYP) system. These systems have fewer complexes and simpler branching patterns than those in energy-transforming organelles, and they are often adapted to non-bioenergetic functions such as detoxification or cellular defense.
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Affiliation(s)
- Stephan Berry
- Plant Biochemistry, Faculty of Biology, Ruhr-University-Bochum, Universitätsstr. 150, D-44780 Bochum, Germany.
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12
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Tasker M, Timms M, Hendriks E, Matthews K. Cytochrome oxidase subunit VI of Trypanosoma brucei is imported without a cleaved presequence and is developmentally regulated at both RNA and protein levels. Mol Microbiol 2001; 39:272-85. [PMID: 11136449 PMCID: PMC2686106 DOI: 10.1046/j.1365-2958.2001.02252.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial respiration in the African trypanosome undergoes dramatic developmental stage regulation. This requires co-ordinated control of components encoded by both the nuclear genome and the kinetoplast, the unusual mitochondrial genome of these parasites. As a model for understanding the co-ordination of these genomes, we have examined the regulation and mitochondrial import of a nuclear-encoded component of the cytochrome oxidase complex, cytochrome oxidase subunit VI (COXVI). By generating transgenic trypanosomes expressing intact or mutant forms of this protein, we demonstrate that COXVI is not imported using a conventional cleaved presequence and show that sequences at the N-terminus of the protein are necessary for correct mitochondrial sorting. Analyses of endogenous and transgenic COXVI mRNA and protein expression in parasites undergoing developmental stage differentiation demonstrates a temporal order of control involving regulation in the abundance of, first, mRNA and then protein. This represents the first dissection of the regulation and import of a nuclear-encoded protein into the cytochrome oxidase complex in these organisms, which were among the earliest eukaryotes to possess a mitochondrion.
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Affiliation(s)
| | | | | | - Keith Matthews
- For correspondence. E-mail ; Tel. (+44) 161 275 5083; Fax (+44) 161 275 5082
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