951
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Church C, Chapon C, Poyton RO. Cloning and characterization of PET100, a gene required for the assembly of yeast cytochrome c oxidase. J Biol Chem 1996; 271:18499-507. [PMID: 8702496 DOI: 10.1074/jbc.271.31.18499] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The biogenesis of cytochrome c oxidase in Saccharomyces cerevisiae requires a protein encoded by the nuclear gene, PET100. Cells carrying a recessive mutation (pet100-1) in PET100 are respiratory deficient and have reduced levels of cytochrome c oxidase activity. The PET100 gene has been cloned by complementation of pet100-1, sequenced and disrupted. PET100 is located adjacent to the PDC2 gene on chromosome IV and contains an open reading frame of 333 base pairs. The PET100 protein contains a possible membrane-spanning segment and a putative mitochondrial import sequence at its NH2 terminus. A strain carrying a null mutation in PET100 lacks cytochrome c oxidase activity and assembled cytochromes a and a3, but the other respiratory chain carriers are present. The respiratory-deficient phenotype of this strain is not rescued by added hemin or heme A. These findings indicate that the mutation is specific for cytochrome c oxidase and does not affect the biosynthesis of heme A. In addition, mitochondria from the strain carrying a null mutation in PET100 contain each of the subunit polypeptides of cytochrome c oxidase. Together, these findings suggest that PET100p is not required for the synthesis or localization of cytochrome c oxidase subunits to mitochondria, but is required at a later step in their assembly into an active holoenzyme.
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Affiliation(s)
- C Church
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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952
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Holm DE, Godette G, Bonaventura C, Bonaventura J, Boatright MD, Pearce LL, Peterson J. A carbon monoxide irreducible form of cytochrome c oxidase and other unusual properties of the "monomeric" shark enzyme. Comp Biochem Physiol B Biochem Mol Biol 1996; 114:345-52. [PMID: 8840511 DOI: 10.1016/0305-0491(96)00031-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Contrary to previous reports, the functional and spectral properties of "monomeric" shark cytochrome c oxidases are not entirely similar to those of the "dimeric" beef enzyme. Most significantly, unlike the behavior of beef oxidase, the fully oxidized shark enzyme is not reducible by carbon monoxide. Also, preparations of the shark enzyme, isolated at pH 7.8-8.0, lead to more than 60% of the sample always being obtained in a resting form, whereas similarly prepared beef oxidase is very often obtained, both by ourselves and others, exclusively in the pulsed form. Although the electronic absorption, magnetic circular dichroism and electron paramagnetic resonance (EPR) spectra of cytochrome c oxidase obtained from several shark species are similar to those of the beef enzyme, there are some significant differences. In particular, the Soret maximum is at 422 nm in the case of the fully oxidized resting shark oxidases at physiological pH and not 418 nm as commonly found for the beef enzyme. Moreover, the resting shark oxidases do not necessarily exhibit a "g = 12" signal in their EPR spectra. The turnover numbers of recent preparations of the shark enzyme are higher than previously reported and, interestingly, do not differ within experimental uncertainty from those documented for several beef isoenzymes assayed under comparable conditions.
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Affiliation(s)
- D E Holm
- Department of Chemistry, University of Alabama, Tuscaloosa 35487-0336, USA
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953
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Park S, Pan LP, Chan SI, Alben JO. Photoperturbation of the heme a3-CuB binuclear center of cytochrome c oxidase CO complex observed by Fourier transform infrared spectroscopy. Biophys J 1996; 71:1036-47. [PMID: 8842240 PMCID: PMC1233558 DOI: 10.1016/s0006-3495(96)79304-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Purified cytochrome c oxidase CO complex from beef heart has been studied by Fourier transform infrared absorbance difference spectroscopy. Photolysis at 10-20 Kelvin results in dissociation of a3FeCO, formation of CuBCO, and perturbation of the a3-heme and CuB complex. The vibrational perturbation spectrum between 900 and 1700 cm-1 contains a wealth of information about the binuclear center. Appearance in infrared photoperturbation difference spectra of virtually all bands previously reported from resonance Raman spectra indicate the importance of polarization along the 4-vinyl:8-formyl axis, which results in the reduction of heme symmetry to C2v. Frequency-shifted bands due to the 8-formyl and 4-vinyl groups of the a3-heme have been identified and quantitated. The frequency shifts have been interpreted as being due to a change in porphyrin polarization with change in spin state of the iron by photodissociation of CO or perturbation of the CuB coordination complex.
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Affiliation(s)
- S Park
- Department of Medical Biochemistry, Ohio State University, Columbus 43210, USA
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954
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Salamon Z, Tollin G. Surface plasmon resonance studies of complex formation between cytochrome c and bovine cytochrome c oxidase incorporated into a supported planar lipid bilayer. II. Binding of cytochrome c to oxidase-containing cardiolipin/phosphatidylcholine membranes. Biophys J 1996; 71:858-67. [PMID: 8842224 PMCID: PMC1233542 DOI: 10.1016/s0006-3495(96)79287-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Complex formation between horse heart cytochrome c (cyt c) and bovine cytochrome c oxidase (cco) incorporated into a supported planar egg phosphatidylcholine membrane containing varying amounts of cardiolipin (CL) (0-20 mol%) has been studied under low (10 mM) and medium (160 mM) ionic strength conditions by surface plasmon resonance (SPR) spectroscopy. Both specific and nonspecific modes of cyt c binding are observed. The dissociation constant of the specific interaction between cyt c and cco increases from approximately 6.5 microM at low ionic strength to 18 microM at medium ionic strength, whereas the final saturation level of bound protein is independent of salt concentration and corresponds to approximately 53% of the total cco molecules present in the membrane. This suggests a 1:1 binding stoichiometry between the two proteins. The nonspecific binding component is governed by electrostatic interactions between cyt c and the membrane lipids and results in a partially ionic strength-reversible protein-membrane association. Thus, hydrophobic interactions between cyt c and the membrane, which are the predominant mode of binding in the absence of cco, are greatly suppressed. Both the amount of nonspecifically bound protein and the binding affinity can be varied over a broad range by changing the ionic strength and the extent of CL incorporation into the membrane. Under conditions approximating the physiological state in the mitochondrion (i.e., 20 mol% CL and medium ionic strength), 1-1.5 cyt c molecules are bound to the lipid phase per molecule of cco, with a dissociation constant of 0.1 microM. The possible physiological significance of these observations is discussed.
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Affiliation(s)
- Z Salamon
- Department of Biochemistry, University of Arizona, Tucson 85721, USA
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955
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Fujii H, Yoshimura T, Kamada H. Synthesis and Characterization of a Binuclear Porphyrin Complex as a Model for Heme a3-CuBSite of CytochromecOxidase. CHEM LETT 1996. [DOI: 10.1246/cl.1996.581] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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956
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Brasseur G, Saribaş AS, Daldal F. A compilation of mutations located in the cytochrome b subunit of the bacterial and mitochondrial bc1 complex. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1275:61-9. [PMID: 8688453 DOI: 10.1016/0005-2728(96)00051-5] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In anticipation of the structure of the bc1 complex which is now imminent, we present here a preliminary compilation of all available cytochrome b mutants that have been isolated or constructed to date both in prokaryotic and eukaryotic species. We have briefly summarized their salient properties with respect to the structure and function of cytochrome b and to the Qo and Qi sites of the bc1 complex. In conjunction with the high resolution structure of the bc1 complex, this database is expected to serve as a useful reference point for the available data and help to focus and stimulate future experimental work in this field.
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Affiliation(s)
- G Brasseur
- Department of Biology, University of Pennsylvania, Philadelphia 19104, USA.
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957
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Ito M, Amagai H, Fukui H, Kitajima N, Moro-oka Y. Synthesis and Characterization of Monomeric (Aryloxo)iron Complexes: [FeIIL(OAr)] and [FeIIIL(OAr)2] {L = BH(3,5-Pri2pz)3−}. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1996. [DOI: 10.1246/bcsj.69.1937] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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958
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Rich PR, Meunier B, Mitchell R, John Moody A. Coupling of charge and proton movement in cytochrome c oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1996. [DOI: 10.1016/0005-2728(96)00055-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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959
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960
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Speijer D, Muijsers AO, Dekker H, de Haan A, Breek CK, Albracht SP, Benne R. Purification and characterization of cytochrome c oxidase from the insect trypanosomatid Crithidia fasciculata. Mol Biochem Parasitol 1996; 79:47-59. [PMID: 8844671 DOI: 10.1016/0166-6851(96)02648-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cytochrome c oxidase was purified from the mitochondrial lysate of the insect trypanosomatid Crithidia fasciculata with the aid of a methyl hydrophobic interaction column in a rapid one-step procedure. The purified complex displayed all characteristics expected from a eukaryotic cytochrome c oxidase: the presence of CuA in electron paramagnetic resonance analysis, a characteristic 605 nm peak in reduced-minus-oxidized optical spectroscopy, and the capacity to efficiently oxidize homologous, but not heterologous, cytochrome c. Two-dimensional PAGE showed that C. fasciculata cytochrome c oxidase consists of at least 10 different subunits. N-terminal sequences were obtained from the six smallest subunits of the complex, one of them showing significant similarity to Neurospora crassa cytochrome c oxidase subunit V. The N-terminus of each of the four largest subunits was found to be blocked.
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Affiliation(s)
- D Speijer
- E.C. Slater Institute, University of Amsterdam, Academic Medical Centre, The Netherlands
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961
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Stange AF, Kaim W. Bis(homoleptische) vs. heteroleptische Kupfer(I)-Komplexe: Elektrosynthese, Spektroskopie und Kristallstruktur von {[Cu(BIK)2]+}2{[Cu4(SR)6]2?} � 3(CH3CN) � (RSH); BIK = Bis(N-methylimidazol-2-yl)keton, R = o-Tolyl. Z Anorg Allg Chem 1996. [DOI: 10.1002/zaac.19966220703] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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962
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Saiki K, Nakamura H, Mogi T, Anraku Y. Probing a role of subunit IV of the Escherichia coli bo-type ubiquinol oxidase by deletion and cross-linking analyses. J Biol Chem 1996; 271:15336-40. [PMID: 8663126 DOI: 10.1074/jbc.271.26.15336] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Subunit IV of the Escherichia coli bo-type ubiquinol oxidase is a 12-kDa membrane protein encoded by the cyoD gene and is conserved in the bacterial heme-copper terminal oxidases. To probe the functional role of subunit IV, we carried out deletion analysis and chemical cross-linking experiments with a homobifunctional and cleavable reagent. Spectroscopic properties of the mutant oxidases suggest that the C-terminal two-third (Val45 to His109) containing helices II and III is essential for the functional expression of the oxidase complex and for the CuB binding to the heme-copper binuclear center in subunit I. Cross-linking studies indicate that subunit IV is in close vicinity to subunit III. Based on these observations, we propose that subunit IV is present in a cleft formed by subunits I and III and assists the CuB binding to subunit I during biosynthesis or assembly of the oxidase complex.
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Affiliation(s)
- K Saiki
- Department of Biological Sciences, Graduate School of Science, the University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan
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963
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Hägerhäll C, Hederstedt L. A structural model for the membrane-integral domain of succinate: quinone oxidoreductases. FEBS Lett 1996; 389:25-31. [PMID: 8682198 DOI: 10.1016/0014-5793(96)00529-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Many succinate:quinone oxidoreductases in bacteria and mitochondria, i.e. succinate:quinone reductases and fumarate reductases, contain in the membrane anchor a cytochrome b whose structure and function is poorly understood. Based on biochemical data and polypeptide sequence information, we show that the anchors in different organisms are related despite an apparent diversity in polypeptide and heme composition. A general structural model for the membrane-integral domain of the anchors is proposed. It is an antiparallel four-helix bundle with a novel arrangement of hexa-coordinated protoheme IX. The structure can be applied to a larger group of membrane-integral cytochromes of b-type and has evolutionary and functional implications.
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Affiliation(s)
- C Hägerhäll
- Department of Microbiology, Lund University, Sweden
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964
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Stange AF, Klinkhammer KW, Kaim W. A Tetragonal Bisphenoidal Tetracopper(I) Arrangement Supported by a Potentially Tridentate Ligand Containing Thiolate, Secondary Amine, and 2-Pyridine Functions: Hydrogen-Bonded Instead of Cu(I)-Coordinated Pyridine Rings in an S(4)-Symmetric Compound. Inorg Chem 1996; 35:4087-4089. [PMID: 11666613 DOI: 10.1021/ic951629j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas F. Stange
- Institut für Anorganische Chemie der Universität, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
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965
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Glerum DM, Shtanko A, Tzagoloff A. Characterization of COX17, a yeast gene involved in copper metabolism and assembly of cytochrome oxidase. J Biol Chem 1996; 271:14504-9. [PMID: 8662933 DOI: 10.1074/jbc.271.24.14504] [Citation(s) in RCA: 327] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mutations in the COX17 gene of Saccharomyces cerevisiae cause a respiratory deficiency due to a block in the production of a functional cytochrome oxidase complex. Because cox17 mutants are able to express both the mitochondrially and nuclearly encoded subunits of cytochrome oxidase, the Cox17p most likely affects some late posttranslational step of the assembly pathway. A fragment of yeast nuclear DNA capable of complementing the mutation has been cloned by transformation of the cox17 mutant with a library of genomic DNA. Subcloning and sequencing of the COX17 gene revealed that it codes for a cysteine-rich protein with a molecular weight of 8,057. Unlike other previously described accessory factors involved in cytochrome oxidase assembly, all of which are components of mitochondria, Cox17p is a cytoplasmic protein. The cytoplasmic location of Cox17p suggested that it might have a function in delivery of a prosthetic group to the holoenzyme. A requirement of Cox17p in providing the copper prosthetic group of cytochrome oxidase is supported by the finding that a cox17 null mutant is rescued by the addition of copper to the growth medium. Evidence is presented indicating that Cox17p is not involved in general copper metabolism in yeast but rather has a more specific function in the delivery of copper to mitochondria.
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Affiliation(s)
- D M Glerum
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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966
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Giuffrè A, D'Itri E, Giannini S, Brunori M, Ubbink-Kok T, Konings WN, Antonini G. The caa3 terminal oxidase of Bacillus stearothermophilus. Transient spectroscopy of electron transfer and ligand binding. J Biol Chem 1996; 271:13987-92. [PMID: 8662862 DOI: 10.1074/jbc.271.24.13987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The thermophilic bacterium Bacillus stearothermophilus possesses a caa3-type terminal oxidase, which was previously purified (De Vrij, W., Heyne, R. I. R., and Konings, W. N. (1989) Eur. J. Biochem. 178, 763-770). We have carried out extensive kinetic experiments on the purified enzyme by stopped-flow time-resolved optical spectroscopy combined with singular value decomposition analysis. The results indicate a striking similarity of behavior between this enzyme and the electrostatic complex between mammalian cytochrome c and cytochrome c oxidase. CO binding to fully reduced caa3 occurs with a second order rate constant (k = 7.8 x 10(4)M-1 s-1) and an activation energy (E* = 6.1 kcal mol-1) similar to those reported for beef heart cytochrome c oxidase. Dithionite reduces cytochrome a with bimolecular kinetics, while cytochrome a3 (and CuB) is reduced via intramolecular electron transfer. When the fully reduced enzyme is mixed with O2, cytochrome a3, and cytochrome c are rapidly oxidized, whereas cytochrome a remains largely reduced in the first few milliseconds. When cyanide-bound caa3 is mixed with ascorbate plus TMPD, cytochrome c and cytochrome a are synchronously reduced; the value of the second order rate constant (k = 3 x 10(5) M-1 s-1 at 30 degrees C) suggests that cytochrome c is the electron entry site. Steady-state experiments indicate that cytochrome a has a redox potential higher than cytochrome c. The data from the reaction with O2 reveal a remarkable similarity in the kinetic, equilibrium, and optical properties of caa3 and the electrostatic complex cytochrome c/cytochrome c oxidase.
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Affiliation(s)
- A Giuffrè
- Department of Biochemical Sciences and CNR Center of Molecular Biology, University of Rome "La Sapienza," 00185 Rome, Italy
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967
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Ogura T, Hirota S, Proshlyakov DA, Shinzawa-Itoh K, Yoshikawa S, Kitagawa T. Time-Resolved Resonance Raman Evidence for Tight Coupling between Electron Transfer and Proton Pumping of Cytochrome c Oxidase upon the Change from the FeV Oxidation Level to the FeIV Oxidation Level. J Am Chem Soc 1996. [DOI: 10.1021/ja951922i] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takashi Ogura
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
| | - Shun Hirota
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
| | - Denis A. Proshlyakov
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
| | - Kyoko Shinzawa-Itoh
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
| | - Shinya Yoshikawa
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
| | - Teizo Kitagawa
- Contribution from the Institute for Molecular Science, Okazaki National Research Institutes and The Graduate University for Advanced Studies, Myodaiji, Okazaki, 444 Japan, and Department of Life Science, Himeji Institute of Technology, Kamigori-cho, Ako-gun, Hyogo 678-02, Japan
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968
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Elliott CM, Derr DL, Ferrere S, Newton MD, Liu YP. Donor/Acceptor Coupling in Mixed-Valent Dinuclear Iron Polypyridyl Complexes: Experimental and Theoretical Considerations. J Am Chem Soc 1996. [DOI: 10.1021/ja954297q] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. Michael Elliott
- Contribution from the Department of Chemistry, Colorado State University, Ft. Collins, Colorado 80523-1872, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Daniel L. Derr
- Contribution from the Department of Chemistry, Colorado State University, Ft. Collins, Colorado 80523-1872, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Suzanne Ferrere
- Contribution from the Department of Chemistry, Colorado State University, Ft. Collins, Colorado 80523-1872, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Marshall D. Newton
- Contribution from the Department of Chemistry, Colorado State University, Ft. Collins, Colorado 80523-1872, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Y.-P. Liu
- Contribution from the Department of Chemistry, Colorado State University, Ft. Collins, Colorado 80523-1872, and Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973
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969
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Cramer WA, Soriano GM, Ponomarev M, Huang D, Zhang H, Martinez SE, Smith JL. SOME NEW STRUCTURAL ASPECTS AND OLD CONTROVERSIES CONCERNING THE CYTOCHROME b6f COMPLEX OF OXYGENIC PHOTOSYNTHESIS. ACTA ACUST UNITED AC 1996; 47:477-508. [PMID: 15012298 DOI: 10.1146/annurev.arplant.47.1.477] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytochrome b6f complex functions in oxygenic photosynthetic membranes as the redox link between the photosynthetic reaction center complexes II and I and also functions in proton translocation. It is an ideal integral membrane protein complex in which to study structure and function because of the existence of a large amount of primary sequence data, purified complex, the emergence of structures, and the ability of flash kinetic spectroscopy to assay function in a readily accessible ms-100 mus time domain. The redox active polypeptides are cytochromes f and b6 (organelle encoded) and the Rieske iron-sulfur protein (nuclear encoded) in a mol wt = 210,000 dimeric complex that is believed to contain 22-24 transmembrane helices. The high resolution structure of the lumen-side domain of cytochrome f shows it to be an elongate (75 A long) mostly beta-strand, two-domain protein, with the N-terminal alpha-amino group as orthogonal heme ligand and an internal linear 11-A bound water chain. An unusual electron transfer event, the oxidant-induced reduction of a significant fraction of the p (lumen)-side cytochrome b heme by plastosemiquinone indicates that the electron transfer pathway in the b6f complex can be described by a version of the Q-cycle mechanism, originally proposed to describe similar processes in the mitochondrial and bacterial bc1 complexes.
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Affiliation(s)
- W. A. Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 49707-1392
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970
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Steiner-Mordoch S, Shirvan A, Schuldiner S. Modification of the pH profile and tetrabenazine sensitivity of rat VMAT1 by replacement of aspartate 404 with glutamate. J Biol Chem 1996; 271:13048-54. [PMID: 8662678 DOI: 10.1074/jbc.271.22.13048] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Vesicular monoamine transporters (VMAT) catalyze transport of serotonin, dopamine, epinephrine, and norepinephrine into subcellular storage organelles in a variety of cells. Accumulation of the neurotransmitter depends on the proton electrochemical gradient (Delta micro H+) across the organelle membrane and involves VMAT-mediated exchange of two lumenal protons with one cytoplasmic amine. Mutagenic analysis of the role of two conserved Asp residues located in transmembrane segments X and XI of rat VMAT type I reveals an important role of these two residues in catalysis. Replacement of Asp 431 with either Glu or Ser inhibits VMAT-mediated [3H]serotonin transport. The mutated proteins are unimpaired in ligand recognition as measured with the high affinity ligand [3H]reserpine or coupling to the proton electrochemical gradient as judged by its ability to accelerate [3H]reserpine binding. Therefore, the Asp residue is needed as such in this position and even a conservative replacement with Glu generates a protein that can catalyze only partial reactions but cannot complete the transport cycle. Replacement of Asp 404 with either Ser or Cys inhibits all VMAT-mediated reactions measured. However, replacement with Glu generated a protein that catalyzed [3H]serotonin transport with modified properties. Whereas the mutated protein binds [3H]reserpine to normal levels and the pH optimum of this reaction is only slightly affected, the optimum pH for transport activity shifted to the acid side and became very sharp; in addition the sensitivity to the inhibitor tetrabenazine increased significantly in this mutated protein. The results point to the need of a carboxyl moiety in position 404. A slight change in its relative location or in the environment around it has a significant effect on the pK of group(s) involved in steps after ligand recognition and coupling to the first H+.
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Affiliation(s)
- S Steiner-Mordoch
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, 91904 Israel
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971
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Tsukihara T, Aoyama H, Yamashita E, Tomizaki T, Yamaguchi H, Shinzawa-Itoh K, Nakashima R, Yaono R, Yoshikawa S. The whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A. Science 1996; 272:1136-44. [PMID: 8638158 DOI: 10.1126/science.272.5265.1136] [Citation(s) in RCA: 1573] [Impact Index Per Article: 56.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The crystal structure of bovine heart cytochrome c oxidase at 2.8 A resolution with an R value of 19.9 percent reveals 13 subunits, each different from the other, five phosphatidyl ethanolamines, three phosphatidyl glycerols and two cholates, two hemes A, and three copper, one magnesium, and one zinc. Of 3606 amino acid residues in the dimer, 3560 have been converged to a reasonable structure by refinement. A hydrogen-bonded system, including a propionate of a heme A (heme a), part of peptide backbone, and an imidazole ligand of CuA, could provide an electron transfer pathway between CuA and heme a. Two possible proton pathways for pumping, each spanning from the matrix to the cytosolic surfaces, were identified, including hydrogen bonds, internal cavities likely to contain water molecules, and structures that could form hydrogen bonds with small possible conformational change of amino acid side chains. Possible channels for chemical protons to produce H2O, for removing the produced water, and for O2, respectively, were identified.
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Affiliation(s)
- T Tsukihara
- Institute for Protein Research, Osaka University, Suita, Japan
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972
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Affiliation(s)
- S Ferguson-Miller
- Department of Biochemistry, Michigan State University, East Lansing, MI 48824-1319, USA.
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973
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Abstract
Oxygen is poisonous, but we cannot live without it. The high oxidizing potential of oxygen molecules (dioxygen) is a valuable source of energy for the organism and its reactivity is low; that is, spin forbidden. However, the dioxygen itself is a 'free radical' and, especially in the presence of transition metals, it is a major promoter of radical reactions in the cell. Humans survive only by virtue of their elaborate defense mechanisms against oxygen toxicity. Iron is the most abundant transition metal in the human body. Because iron shows wide variation in redox potential with different co-ordination ligands, it may be used as a redox intermediate in many biological mechanism. However, it is precisely this redox activeness that makes iron a key participant in free radical production. The current research on the relationship between iron and cancer is briefly reviewed. Research results are reported here which indicate that iron, when bound to certain ligands, can cause free-radical mediated tissue damage and become carcinogenic. The present study also suggests that iron may also have a significant role in spontaneous human cancer.
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Affiliation(s)
- S Okada
- First Department of Pathology, Okayama University Medical School, Japan
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974
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Malatesta F, Antonini G, Nicoletti F, Giuffrè A, D'Itri E, Sarti P, Brunori M. Probing the high-affinity site of beef heart cytochrome c oxidase by cross-linking. Biochem J 1996; 315 ( Pt 3):909-16. [PMID: 8645176 PMCID: PMC1217293 DOI: 10.1042/bj3150909] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A covalent complex between cytochrome c oxidase and Saccharomyces cerevisiae iso-1-cytochrome c (called caa3) has been prepared at low ionic strength. Subunit III Cys-115 of beef heart cytochrome c oxidase cross-links by disulphide bond formation to thionitrobenzoate-modified yeast cytochrome c, a derivative shown to bind into the high-affinity site for substrate [Fuller, Darley-Usmar and Capaldi (1981) Biochemistry 20, 7046-7053]. Stopped-flow experiments show that (1) covalently bound yeast cytochrome c cannot donate electrons to cytochrome oxidase, whereas oxidation of exogenously added cytochrome c and electron transfer to cytochrome a are only slightly affected; (2) the steady-state reduction levels of cytochrome c and cytochrome a in the covalent complex caa3 are higher than those found in the native aa3 enzyme. However, (3) K(m) and Vmax values obtained from the non-linear Eadie-Hofstee plots are very similar in both caa3 and aa3. The results imply that cytochrome c bound to the high-affinity site is not in a configuration optimal for electron transfer.
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Affiliation(s)
- F Malatesta
- Dipartimento di Biologia di Base ed Applicata, Universita' di L'Aquila, Italy
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975
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Schäfer G, Purschke W, Schmidt CL. On the origin of respiration: electron transport proteins from archaea to man. FEMS Microbiol Rev 1996; 18:173-88. [PMID: 8639327 DOI: 10.1111/j.1574-6976.1996.tb00235.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
All aerobic organisms use the exergonic reduction of molecular oxygen to water as primary source of metabolic energy. This reaction is catalyzed by membrane residing terminal heme/Cu-oxidases which belong to a superfamily of widely varying structural complexity between mitochondrial and bacterial members of this family. Over the last few years, considerable information from this and other laboratories accumulated also on archaeal respiratory chains and their terminal oxidases. In the following, the molecular and catalytic properties of the latter are discussed and compared to those from bacteria and eucarya under the aspect of their energy conserving capabilities and their phylogenetic relations. The Rieske iron-sulfur proteins being important functional constituents of energy transducing respiratory complexes are included in this study. A number of essential conclusions can be drawn. (1) Like bacteria, archaea can also contain split respiratory chains with parallel expression of separate terminal oxidases. (2) The functional core of all oxidases is the highly conserved topological motif of subunit I consisting of at least 12 membrane spanning helices with the 6 histidine residues of the heme/Cu-binding centers in identical locations. (3) Some archaeal oxidases are organized in unusual supercomplexes with other cytochromes and Rieske [2Fe2S] proteins. These complexes are likely to function as proton pumps, whereas on a structural basis several subunit I equivalents alone are postulated to be unable to pump protons. (4) The genes of two archaeal Rieske proteins have been cloned from Sulfolobus; phylogenetically they are forming a separate archaeal branch and suggest the existence of an evolutionary ancestor preceding the split into the three urkingdoms. (5) Archaeal oxidase complexes may combine features of electron transport systems occurring exclusively as separate respiratory complexes in bacteria and eucarya. (6) As far back as the deepest branches of the phylogentic tree, terminal oxidases reveal a degree of complexity comparable to that found in higher organisms. (7) Sequence analysis suggests a monophyletic origin of terminal oxidases with an early split into two types found in archaea as well as bacteria. This view implies an origin of terminal oxidases prior to oxygenic photosynthesis in contrast to the widely accepted inverse hypothesis.
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Affiliation(s)
- G Schäfer
- Institute of Biochemistry, Medical University of Lübeck, Germany
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976
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Hellwig P, Rost B, Kaiser U, Ostermeier C, Michel H, Mäntele W. Carboxyl group protonation upon reduction of the Paracoccus denitrificans cytochrome c oxidase: direct evidence by FTIR spectroscopy. FEBS Lett 1996; 385:53-7. [PMID: 8641466 DOI: 10.1016/0014-5793(96)00342-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The redox reactions of the cytochrome c oxidase from Paracoccus denitrificans were investigated in a thin-layer cell designed for the combination of electrochemistry under anaerobic conditions with UV/VIS and IR spectroscopy. Quantitative and reversible electrochemical reactions were obtained at a surface-modified electrode for all cofactors as indicated by the optical signals in the 400-700 nm range. Fourier transform infrared (FTIR) difference spectra of reduction and oxidation (reduced-minus-oxidized and oxidized-minus-reduced, respectively) obtained in the 1800-1000 cm(-1) range reveal highly structured band features with major contributions in the amide I (1620-1680 cm(-1)) and amide II (1580-1520 cm(-1)) range which indicate structural rearrangements in the cofactor vicinity. However, the small amplitude of the IR difference signals indicates that these conformational changes are small and affect only individual peptide groups. In the spectral region above 1700 cm(-1), a positive peak in the reduced state (1733 cm(-1)) and negative peak in the oxidized st ate (1745 cm(-1)) are characteristic for the formation and decay of a COOH mode upon reduction. The most obvious interpretation of this difference signal is proton uptake by one Asp or Glu side chain carboxyl group in the reduced state and deprotonation of another Asp or Glu residue. Moreover, both residues could well be coupled as a donor-acceptor pair in the proton transfer chain. An alternative interpretation is in terms of a protonated carboxyl group which shifts to a different environment in the reduced state. The relevance of this first direct observation of protein protonation changes in the cytochrome c oxidase for vectorial proton transfer and the catalytic reaction is discussed.
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Affiliation(s)
- P Hellwig
- Institut für Physikalishce und Theoretische Chemie der Universität Erlangen-Nürnberg, Germany
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977
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Wallace-Williams SE, James CA, de Vries S, Saraste M, Lappalainen P, van der Oost J, Fabian M, Palmer G, Woodruff WH. Far-Red Resonance Raman Study of Copper A in Subunit II of Cytochrome c Oxidase. J Am Chem Soc 1996. [DOI: 10.1021/ja953646d] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stacie E. Wallace-Williams
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Chris A. James
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Simon de Vries
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Matti Saraste
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Pekka Lappalainen
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - John van der Oost
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Marian Fabian
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - Graham Palmer
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
| | - William H. Woodruff
- CST-4, Los Alamos National Laboratory Mail Stop G758, Los Alamos, New Mexico 87545 Technical University Delft, The Netherlands European Molecular Biology Laboratory Heidelberg, Germany Vrije Universiteit, Amsterdam, The Netherlands Rice University, Houston, Texas 77251
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978
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Scott MJ, Goddard CA, Holm RH. Molecular Assemblies Containing Unsupported [Fe(III)-(&mgr;(2):eta(2)-RCO(2))-Cu(II)] Bridges. Inorg Chem 1996; 35:2558-2567. [PMID: 11666470 DOI: 10.1021/ic9512035] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Formate is an inhibitor of cytochrome oxidases and also effects conversion of the bovine heart enzyme from the "fast" to the "slow" cyanide-binding form. The molecular basis of these effects is unknown; one possibility is that formate inserts as a bridge into the binuclear heme a(3)-Cu(B) site, impeding the binding of dioxygen or cyanide. Consequently, Fe-Cu-carboxylate interactions are a matter of current interest. We have initiated an examination of such interactions by the synthesis of the first examples of [Fe(III)-(&mgr;(2):eta(2)-RCO(2))-Cu(II)] bridges, minimally represented by Fe(III)-L + Cu(II)-O(2)CR --> [Fe(III)-(RCO(2))-Cu(II)] + L. A series of Cu(II) precursor complexes and solvate forms have been prepared and their structures determined, including [Cu(Me(5)dien)(O(2)CH)](+) (3), [Cu(Me(5)dien)(O(2)CH)(MeOH)](+) (4), [Cu(Me(6)tren)(O(2)CH)](+) (5), and [Cu(Me(5)dien)(OAc)](+) (6). [4](ClO(4)) was obtained in monoclinic space group P2(1)/n with a = 8.166(3) Å, b = 15.119(5) Å, c = 15.070(4) Å, beta = 104.65(2) degrees, and Z = 4. [5](ClO(4))/[6](ClO(4)) crystallize in orthorhombic space groups Pnma/Pna2(1) with a = 16.788(2)/14.928(5) Å, b = 9.542(1)/9.341(4) Å, c = 12.911(1)/12.554(4) Å, and Z = 4/4. In all cases, the carboxylate ligand is terminal and is bound in a syn orientation. Also prepared for the purpose of structural comparison was [Fe(OEP)(O(2)CH)], which occurred in monoclinic space group P2(1)/c with a = 13.342(2) Å, b = 13.621(2) Å, c = 19.333(2) Å, beta = 106.12(2) degrees, and Z = 4. The desired bridges were stabilized in the assemblies [(OEP)Fe(O(2)CH)Cu(Me(5)dien)(OClO(3))](+) (9), [(OEP)Fe(OAc)Cu(Me(5)dien)](2+) (10), and {(OEP)Fe[(O(2)CH)Cu(Me(6)tren)](2)}(3+) (11), which were prepared by the reaction of 3, 6, and 5, respectively, with [Fe(OEP)(OClO(3))] in acetone or dichloromethane. [9](ClO(4))/[10](ClO(4))(2).CH(2)Cl(2) crystallize in triclinic space group P&onemacr; with a = 9.016(3)/13.777(3) Å, b = 15.377(5)/13.847(3) Å, c = 19.253(5)/17.608(4) Å, alpha = 78.12(3)/96.82(3) degrees, beta = 86.30(4)/108.06(3) degrees, gamma = 76.23(3)/114.32(3) degrees, and Z = 2/2. Each assembly contains a [Fe(III)-(RCO(2))-Cu(II)] bridge but with the differing orientations anti-anti (9) and syn-anti (10, 11). The compound [11](ClO(4))(2)(SbF(6)) occurs in orthorhombic space group Pbcn with a = 12.517(6) Å, b = 29.45(1) Å, c = 21.569(8) Å, and Z = 4. Complex 11 is trinuclear; the Fe(III) site has two axial formate ligands with bond distances indicative of a high-spin configuration. Structural features of 9-11 are discussed and are considered in relation to the possible insertion of formate into the binuclear sites of two oxidases whose structures were recently determined. The present results contribute to the series of molecular assemblies with the bridge groups [Fe(III)-X-Cu(II)], X = O(2)(-), OH(-), and RCO(2)(-), all with a common high-spin heme, thereby allowing an examination of electronic structure as dependent on the bridging atom or group and bridge structure. (Me(5)dien = 1,1,4,7,7-pentamethyldiethylenetriamine; Me(6)tren = tris(2-(dimethylamino)ethyl)amine; OEP = octaethylporphyrinate(2-).)
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Affiliation(s)
- Michael J. Scott
- Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138
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979
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Overholtzer MH, Yakowec PS, Cameron V. The effect of amino acid substitutions in the conserved aromatic region of subunit II of cytochrome c oxidase in Saccharomyces cerevisiae. J Biol Chem 1996; 271:7719-24. [PMID: 8631812 DOI: 10.1074/jbc.271.13.7719] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial encoded subunit II of cytochrome c oxidase carries the metal center, which acts as the initial acceptor of electrons from cytochrome c. Among the conserved features of this protein is a region in which five aromatic and three non-aromatic amino acids are conserved in a wide variety of organisms. This aromatic region has been postulated to be involved in transfer of electrons from the copper center in subunit II to the remaining metal centers of cytochrome oxidase in subunit I. To test the functional importance of two conserved, aromatic tryptophan residues and one conserved, non-aromatic glycine residue, yeast strains with alterations at these positions were characterized. The strains with altered codons were tested for their ability to carry out cellular respiration, for their growth rates on non-fermentable carbon sources, and for their cytochrome c oxidase activity. The results demonstrate that the aromatic character of the tryptophan residues appears necessary for subunit II function, while the conserved glycine can be replaced with other, small, uncharged residues.
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980
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Antaramian A, Coria R, Ramírez J, González-Halphen D. The deduced primary structure of subunit I from cytochrome c oxidase suggests that the genus Polytomella shares a common mitochondrial origin with Chlamydomonas. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1273:198-202. [PMID: 8616156 DOI: 10.1016/0005-2728(95)00158-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We cloned and sequenced the mitochondrial gene encoding subunit I of cytochrome c oxidase (coxI) of Polytomella spp., a colorless alga related to Chlamydomonas. The purpose was to explore whether homology between the two species also exists at the level of a mitochondrial enzyme. The gene is 1512 bp long and contains no introns. The translated protein sequence exhibits 73.8% identity with its Chlamydomonas reinhardtii counterpart. The data obtained support the hypothesis that the separation of the colorless alga from the Chlamydomonas lineage was a late event in evolution, that occurred after the endosymbiotic process that gave rise to mitochondria.
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Affiliation(s)
- A Antaramian
- Departamento de Bioenergética, Instituto de Fisiología Celular, U.N.A.M., Mexico City 045100, Mexico
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981
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Frank V, Kadenbach B. Regulation of the H+/e- stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios. FEBS Lett 1996; 382:121-4. [PMID: 8612732 DOI: 10.1016/0014-5793(96)00096-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This paper describes the effect of intramitochondrial ATP/ADP ratios on the H+/e- stoichiometry of reconstituted cytochrome c oxidase (COX) from bovine heart. At 100% intraliposomal ATP the H+/e- stoichiometry of the reconstituted enzyme is decreased to half of the value measured below 98% intraliposomal ATP (above 2% ADP), while it remains constant up to 100% ADP. The decrease is obtained with different COX preparations, independent of the absolute value of the H+/e- stoichiometry. Decrease of H+/e- stoichiometry is prevented by preincubation of the enzyme with a tissue-specific monoclonal antibody to subunit VIa-H (heart type). Tissue-specific regulation of the efficiency of energy transduction in COX of muscle mitochondria could have a physiological function in maintaining the body temperature at rest or sleep, i.e. at low ATP expenditure.
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Affiliation(s)
- V Frank
- Fachbereich Chemie, Philipps-Universität, Marburg, Germany
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982
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Abstract
A catalytic transformation of dihydrogen into two protons and two electrons has been discovered with a ruthenium/iron complex. The chemical reactions of complexes between transition metals and dihydrogen give insights into the function of biological hydrogenases.
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Affiliation(s)
- J P Collman
- Department of Chemistry, Stanford University, California 94305, USA
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983
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Houser RP, Young VG, Tolman WB. A Thiolate-Bridged, Fully Delocalized Mixed-Valence Dicopper(I,II) Complex That Models the CuA Biological Electron-Transfer Site. J Am Chem Soc 1996. [DOI: 10.1021/ja953776m] [Citation(s) in RCA: 160] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert P. Houser
- Department of Chemistry, University of Minnesota 207 Pleasant Street SE, Minneapolis, Minnesota 55455
| | - Victor G. Young
- Department of Chemistry, University of Minnesota 207 Pleasant Street SE, Minneapolis, Minnesota 55455
| | - William B. Tolman
- Department of Chemistry, University of Minnesota 207 Pleasant Street SE, Minneapolis, Minnesota 55455
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984
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Speijer D, Breek CK, Muijsers AO, Groenevelt PX, Dekker H, de Haan A, Benne R. The sequence of a small subunit of cytochrome c oxidase from Crithidia fasciculata which is homologous to mammalian subunit IV. FEBS Lett 1996; 381:123-6. [PMID: 8641419 DOI: 10.1016/0014-5793(96)00095-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The sequence of subunit 8 of cytochrome c oxidase from Crithidia fasciculata was determined by sequencing cDNA and N-terminus of the mature protein (Mr = 15.7 kDA). The (inferred) protein is homologous to mammalian cox IV and the corresponding cox subunits from yeast, Neurospora crassa and Dictyostelium discoideum, which is reflected in a very similar hydropathy profile. Elements that are conserved in the C. fasciculata sequence include (i) an N-terminal (D/E)-(K/R)-X-K-(X2)-W-(X2)-(I/L) motif, (ii) a putative membrane-spanning region in the middle portion of the protein, and (iii) a C-terminal W-(X13)-(N/D)-P motif. The C. fasciculata protein is synthesized with a cleavable presequence.
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Affiliation(s)
- D Speijer
- E.C. Slater Institute, University of Amsterdam, Academic Medical Centre, The Netherlands
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985
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Tsubaki M, Mogi T, Hori H, Sato-Watanabe M, Anraku Y. Infrared and EPR studies on cyanide binding to the heme-copper binuclear center of cytochrome bo-type ubiquinol oxidase from Escherichia coli. Release of a CuB-cyano complex in the partially reduced state. J Biol Chem 1996; 271:4017-22. [PMID: 8626734 DOI: 10.1074/jbc.271.8.4017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cyanide-binding to the heme-copper binuclear center of bo-type ubiquinol oxidase from Escherichia coli was investigated with Fourier transform-infrared and EPR spectroscopies. Upon treatment of the air-oxidized CN-inhibited enzyme with excess sodium dithionite, a 12C-14N stretching vibration at 2146 cm-1 characteristic of the FeO3+ C=N CuB2+ bridging structure was quickly replaced with another stretching mode at 2034.5 cm-1 derived from the FeO2+ C=N moiety. The presence of ubiquinone-8 or ubiquinone-1 caused a gradual autoreduction of the metal center(s) of the air-oxidized CN-inhibited enzyme and a concomitant appearance of a strong cyanide stretching band at 2169 cm-1. This 2169 cm-1 species could not be retained with a membrane filter (molecular weight cutoff = 10,000) and showed unusual cyanide isotope shifts and a D2O shift. These observations together with metal content analyses indicate that the 2169 cm-1 band is due to a CuB.CN complex released from the enzyme. The same species could be produced by anaerobic partial reduction of the CN-inhibited ubiquinol oxidase and, furthermore, of the CN-inhibited cytochrome c oxidase; but not at all from the fully reduced CN-inhibited enzymes. These findings suggest that there is a common intermediate structure at the binuclear center of heme-copper respiratory enzymes in the partially reduced state from which the CuB center can be easily released upon cyanide-binding.
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Affiliation(s)
- M Tsubaki
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigoori-cho, Akou-gun, Hyogo 678-12, Japan
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986
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Dooley DM, Alvarez ML, Rosenzweig AC, Scott Hollis R, Zumft WG. Exogenous ligand binding to Pseudomonas stutzeri nitrous oxide reductase. Inorganica Chim Acta 1996. [DOI: 10.1016/0020-1693(95)04873-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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987
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988
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Babcock GT, Floris R, Nilsson T, Pressler M, Varotsis C, Vollenbroek E. Dioxygen activation in enzymatic systems and in inorganic models. Inorganica Chim Acta 1996. [DOI: 10.1016/0020-1693(96)04925-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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989
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Fox S, Nanthakumar A, Wikström M, Karlin KD, Blackburn NJ. XAS Structural Comparisons of Reversibly Interconvertible Oxo- and Hydroxo-Bridged Heme-Copper Oxidase Model Compounds. J Am Chem Soc 1996. [DOI: 10.1021/ja951686b] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen Fox
- Contribution from the Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Medical Chemistry, FIN-00014, University of Helsinki, Finland, and Department of Chemistry and Biological Sciences, Oregon Graduate Institute, Beaverton, Oregon 97006
| | - Alaganandan Nanthakumar
- Contribution from the Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Medical Chemistry, FIN-00014, University of Helsinki, Finland, and Department of Chemistry and Biological Sciences, Oregon Graduate Institute, Beaverton, Oregon 97006
| | - Mårten Wikström
- Contribution from the Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Medical Chemistry, FIN-00014, University of Helsinki, Finland, and Department of Chemistry and Biological Sciences, Oregon Graduate Institute, Beaverton, Oregon 97006
| | - Kenneth D. Karlin
- Contribution from the Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Medical Chemistry, FIN-00014, University of Helsinki, Finland, and Department of Chemistry and Biological Sciences, Oregon Graduate Institute, Beaverton, Oregon 97006
| | - Ninian J. Blackburn
- Contribution from the Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Medical Chemistry, FIN-00014, University of Helsinki, Finland, and Department of Chemistry and Biological Sciences, Oregon Graduate Institute, Beaverton, Oregon 97006
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990
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Hay M, Richards JH, Lu Y. Construction and characterization of an azurin analog for the purple copper site in cytochrome c oxidase. Proc Natl Acad Sci U S A 1996; 93:461-4. [PMID: 8552661 PMCID: PMC40258 DOI: 10.1073/pnas.93.1.461] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A protein analog of a purple copper center has been constructed from a recombinant blue copper protein (Pseudomonas aeruginosa azurin) by replacing the loop containing the three ligands to the blue copper center with the corresponding loop of the CuA center in cytochrome c oxidase (COX) from Paracoccus denitrificans. The electronic absorption in the UV and visible region (UV-vis) and electron paramagnetic resonance (EPR) spectra of this analog are remarkably similar to those of the native CuA center in COX from Paracoccus denitrificans. The above spectra can be obtained upon addition of a mixture of Cu2+ and Cu+. Addition of Cu2+ only results in a UV-vis spectrum consisting of absorptions from both a purple copper center and a blue copper center. This spectrum can be converted to the spectrum of a pure purple copper by a prolonged incubation in the air, or by addition of excess ascorbate. The azurin mutant reported here is an example of an engineered purple copper center with the A480/A530 ratio greater than 1 and with no detectable hyperfines, similar to those of the CuA sites in COX of bovine heart and of Paracoccus denitrificans.
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Affiliation(s)
- M Hay
- Department of Chemistry, University of Illinois, Urbana 61801, USA
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991
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992
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Abstract
Defects in a pathway as complex as the electron transport chain cause a variety of clinical abnormalities, which vary from fatal lactic acidosis in infancy to mild muscle disease in adults. The primary defect may reside in the nucleus or the mitochondrial genome. Until relatively recently, biochemical assays were the definitive means of establishing a defect of the electron transport chain. However, identification of mtDNA abnormalities allows defects to be defined more precisely and in a number of cases provides an easier (more reliable) means of investigation. Despite advances in this field, disorders of the electron transport chain still remain underdiagnosed. This review attempts to provide a general outline of the biochemistry and molecular genetics associated with these disorders and some of the factors involved in establishing a diagnosis in those patients with a suspected defect of the electron transport chain.
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Affiliation(s)
- P L Adams
- Department of Neurology, Medical School, University of Newcastle upon Tyne, UK
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993
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Konings WN, Kaback HR, Lolkema JS. Preface to volume 2 Transport processes in eukaryotic and prokaryotic organisms. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1383-8121(96)80040-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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994
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Franceschi F, Gullotti M, Monzani E, Casella L, Papaefthymiou V. Cytochrome c oxidase models. A novel dinuclear iron–copper complex derived from a covalently modified deuteroporphyrin–L-histidine–bis(benzimidazole) ligand. Chem Commun (Camb) 1996. [DOI: 10.1039/cc9960001645] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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995
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Branscombe NDJ, Blake AJ, Marin-Becerra A, Li WS, Parsons S, Ruiz-Ramirez L, Schröder M. Synthesis and structure of tetranuclear zinc(II) and binuclear copper(II) complexes of a dithiolate compartmental macrocyclic ligand: a model for the binuclear CuAsite in cytochrome c oxidase and N2O reductase. Chem Commun (Camb) 1996. [DOI: 10.1039/cc9960002573] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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996
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von Heijne G. Principles of membrane protein assembly and structure. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1996; 66:113-39. [PMID: 9175426 DOI: 10.1016/s0079-6107(97)85627-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- G von Heijne
- Department of Biochemistry, Stockholm University, Sweden
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997
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Abstract
The crystal structures of two cytochrome c oxidases, one bacterial and one mammalian, offer insights into their roles in oxygen chemistry and as proton pumps.
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Affiliation(s)
- R B Gennis
- School of Chemical Sciences, University of Illinois, Urbana 61801, USA
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998
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Ramirez BE, Malmström BG, Winkler JR, Gray HB. The currents of life: the terminal electron-transfer complex of respiration. Proc Natl Acad Sci U S A 1995; 92:11949-51. [PMID: 8618820 PMCID: PMC40272 DOI: 10.1073/pnas.92.26.11949] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- B E Ramirez
- Beckman Institute, California Institute of Technology, Pasadena 91125, USA
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999
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Choe S, Stevens CF, Sullivan JM. Three distinct structural environments of a transmembrane domain in the inwardly rectifying potassium channel ROMK1 defined by perturbation. Proc Natl Acad Sci U S A 1995; 92:12046-9. [PMID: 8618841 PMCID: PMC40293 DOI: 10.1073/pnas.92.26.12046] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To probe the protein environment of an ion channel, we have perturbed the structure of a transmembrane domain by substituting side chains with those of two different sizes by using site-specific mutagenesis. We have used Trp and Ala as a high- and a low-impact perturbation probe, respectively, to replace each of 18 consecutive residues within the putative second transmembrane segment, M2, of an inwardly rectifying potassium channel, ROMK1. Our rationale is that a change in the channel function as a consequence of these mutations at a particular position will reflect the structural environment of the altered side chain. Each position can then be assigned to one of three classes of environments, as grated by different levels of perturbation: very tolerant (channel functions with both Trp and Ala substitutions), tolerant (function preserved with Ala but not with Trp substitution), and intolerant (either Ala or Trp substitution destroys function). We identify the very tolerant environment as being lipid-facing, tolerant as protein-interior-facing, and intolerant as pore-facing. We observe a strikingly ordered pattern of perturbation of all three environmental classes. This result indicates that M2 is a straight alpha-helix.
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Affiliation(s)
- S Choe
- Structural Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
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1000
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Kadenbach B. Die Kristallstrukturen der Cytochrom-c-Oxidasen ausParacoccus denitrificans und Rinderherz – zum molekularen Mechanismus der Zellatmung. Angew Chem Int Ed Engl 1995. [DOI: 10.1002/ange.19951072306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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