Journal articles: 'Cytochrome C oxidase'

1

Otten, Marijke F., John van der Oost, Willem N. M. Reijnders, Hans V. Westerhoff, Bernd Ludwig, and Rob J. M. Van Spanning. "Cytochromes c550,c552, and c1 in the Electron Transport Network of Paracoccus denitrificans: Redundant or Subtly Different in Function?" Journal of Bacteriology 183, no. 24 (December 15, 2001): 7017–26. http://dx.doi.org/10.1128/jb.183.24.7017-7026.2001.

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ABSTRACT Paracoccus denitrificans strains with mutations in the genes encoding the cytochrome c 550,c 552, or c 1 and in combinations of these genes were constructed, and their growth characteristics were determined. Each mutant was able to grow heterotrophically with succinate as the carbon and free-energy source, although their specific growth rates and maximum cell numbers fell variably behind those of the wild type. Maximum cell numbers and rates of growth were also reduced when these strains were grown with methylamine as the sole free-energy source, with the triple cytochromec mutant failing to grow on this substrate. Under anaerobic conditions in the presence of nitrate, none of the mutant strains lacking the cytochrome bc 1 complex reduced nitrite, which is cytotoxic and accumulated in the medium. The cytochrome c 550-deficient mutant did denitrify provided copper was present. The cytochromec 552 mutation had no apparent effect on the denitrifying potential of the mutant cells. The studies show that the cytochromes c have multiple tasks in electron transfer. The cytochrome bc 1 complex is the electron acceptor of the Q-pool and of amicyanin. It is also the electron donor to cytochromes c 550 andc 552 and to thecbb 3-type oxidase. Cytochromec 552 is an electron acceptor both of the cytochrome bc 1 complex and of amicyanin, as well as a dedicated electron donor to theaa 3-type oxidase. Cytochromec 550 can accept electrons from the cytochrome bc 1 complex and from amicyanin, whereas it is also the electron donor to both cytochromec oxidases and to at least the nitrite reductase during denitrification. Deletion of the c-type cytochromes also affected the concentrations of remaining cytochromes c, suggesting that the organism is plastic in that it adjusts its infrastructure in response to signals derived from changed electron transfer routes.

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2

Kornblatt, Jack A., Janice Theodorakis, Gaston Hui Bon Hoa, and Emmanuel Margoliash. "Cytochrome c and cytochrome c oxidase interactions: the effects of ionic strength and hydrostatic pressure studied with site-specific modifications of cytochrome c." Biochemistry and Cell Biology 70, no. 7 (July 1, 1992): 539–47. http://dx.doi.org/10.1139/o92-084.

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Seven cytochromes c, in which individual lysines have been modified to the propylthiobimane derivatives, have been prepared. These derivatives were also converted to the porphyrin cytochromes c by treatment with HF. The properties of both types of modified proteins were studied in their reactions with cytochrome c oxidase. The results show that lysines 25, 27, 60, 72, and 87 do not contribute a full charge to the binding interaction with the oxidase. These five residues, with the exception of the lysine-60 derivative, are on the front surface of the protein and contain the solvent-accessible edge of the heme prosthetic group. By contrast, lysines 8 and 13 at the top of the front surface do contribute a full charge to the binding interaction with the oxidase. The removal of the positive charge on any one lysine weakens the binding to cytochrome c oxidase by at least 1 kcal (1 cal = 4.1868 J). The presence of bimane at lysines 13 and 87 clearly forces the separation of the cytochrome c and oxidase, but this does not occur with the other complexes. The bimane-modified lysine-13 protein, and to a lesser extent that modified at lysine 8, show the interesting effect of enhanced complex formation with cytochrome c oxidase when subjected to pressure, possibly because of entrapment of water at the newly created interface of the complex. Our observations indicate that the two proteins of the cytochrome c – cytochrome oxidase complex have preferred, but not obligatory, spatial orientations and that interaction occurs without either protein losing significant portions of its hydration shell.Key words: cytochrome oxidase, cytochrome c, binding, hydrostatic pressure.

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3

Kossekova, G., B. Atanasov, R. Bolli, and A. Azzi. "Ionic-strength-dependence of the oxidation of native and pyridoxal 5′-phosphate-modified cytochromes c by cytochrome c oxidase." Biochemical Journal 262, no. 2 (September 1, 1989): 591–96. http://dx.doi.org/10.1042/bj2620591.

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The ionic-strength-dependences of the rate constants (log k plotted versus square root of 1) for oxidation of native and pyridoxal 5′-phosphate-modified cytochromes c by three different preparations of cytochrome c oxidase have complex non-linear character, which may be explained on the basis of present knowledge of the structure of the oxidase and the monomer-dimer equilibrium of the enzyme. The wave-type curve (with a minimum and a maximum) for oxidation of native cytochrome c by purified cytochrome c oxidase depleted of phospholipids may reflect consecutively inhibition of oxidase monomers (initial descending part), competition between this inhibition and dimer formation, resulting in increased activity (second part with positive slope), and finally inhibition of oxidase dimers (last descending part of the curve). The dependence of oxidation of native cytochrome c by cytochrome c oxidase reconstituted into phospholipid vesicles is a curve with a maximum, without the initial descending part described above. This may reflect the lack of pure monomers in the vesicles, where equilibrium is shifted to dimers even at low ionic strength. Subunit-III-depleted cytochrome c oxidase does not exhibit the maximum seen with the other two enzyme preparations. This may mean that removal of subunit III hinders dimer formation. The charge interactions of each of the cytochromes c (native or modified) with the three cytochrome c oxidase preparations are similar, as judged by the similar slopes of the linear dependences at I values above the optimal one. This shows that subunit III and the phospholipid membrane do not seem to be involved in the specific charge interaction of cytochrome c oxidase with cytochrome c.

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4

Sampson, Valerie, and Trevor Alleyne. "Cytochrome c /cytochrome c oxidase interaction." European Journal of Biochemistry 268, no. 24 (December 15, 2001): 6534–44. http://dx.doi.org/10.1046/j.0014-2956.2001.02608.x.

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5

Ostermeier, C. "Cytochrome c oxidase." Current Opinion in Structural Biology 6, no. 4 (August 1996): 460–66. http://dx.doi.org/10.1016/s0959-440x(96)80110-2.

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6

Taanman, J. W., and S. L. Williams. "Assembly of cytochrome c oxidase: what can we learn from patients with cytochrome c oxidase deficiency?" Biochemical Society Transactions 29, no. 4 (August 1, 2001): 446–51. http://dx.doi.org/10.1042/bst0290446.

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Cytochrome c oxidase is an intricate metalloprotein that transfers electrons from cytochrome c to oxygen in the last step of the mitochondrial respiratory chain. It uses the free energy of this reaction to sustain a transmembrane electrochemical gradient of protons. Site-directed mutagenesis studies of bacterial terminal oxidases and the recent availability of refined crystal structures of the enzyme are rapidly expanding the understanding of the coupling mechanism between electron transfer and proton translocation. In contrast, relatively little is known about the assembly pathway of cytochrome c oxidase. Studies in yeast have indicated that assembly is dependent on numerous proteins in addition to the structural subunits and prosthetic groups. Human homologues of a number of these assembly factors have been identified and some are now known to be involved in disease. To dissect the assembly pathway of cytochrome c oxidase, we are characterizing tissues and cell cultures derived from patients with genetically defined cytochrome c oxidase deficiency, using biochemical, biophysical and immunological techniques. These studies have allowed us to identify some of the steps of the assembly process.

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7

Nicholls, Peter. "Control of proteoliposomal cytochrome c oxidase: the partial reactions." Biochemistry and Cell Biology 68, no. 9 (September 1, 1990): 1135–41. http://dx.doi.org/10.1139/o90-169.

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The steady-state spectroscopic behaviour and the turnover of cytochrome c oxidase incorporated into proteoliposomes have been investigated as functions of membrane potential and pH gradient. The respiration rate is almost linearly dependent on [cytochrome c2+] at high flux, but while the cytochrome a redox state is always dependent on the [cytochrome c2+] steady state, it reaches a maximum reduction level less than 100% in each case. The maximal aerobic steady-state reduction level of cytochrome a is highest in the presence of valinomycin and lowest in the presence of nigericin. The proportion of [cytochrome c2+] required to achieve 50% of maximal reduction of cytochrome a varies with the added ionophores; the apparent redox potential of cytochrome a is most positive in the fully decontrolled system (plus valinomycin and nigericin). At low levels of cytochrome a reduction, the rate of respiration is no longer a linear function of [cytochrome c2+], but is dependent upon the redox state of both cytochromes a and c. That is, proteoliposomal oxidase does not follow Smith–Conrad kinetics at low cytochrome c reduction levels, especially in the controlled states. The control of cytochrome oxidase turnover by ΔpH and by ΔΨ can be explained either by an allosteric model or by a model with reversed electron transfer between the binuclear centre and cytochrome a. Other evidence suggests that the reversed electron transfer model may be the correct one.Key words: proteoliposomes, cytochrome c, cytochrome oxidase, membrane potential, pH gradient, cytochrome a, electron transfer.

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8

Bengtsson, Jenny, Claes von Wachenfeldt, Lena Winstedt, Per Nygaard, and Lars Hederstedt. "CtaG is required for formation of active cytochrome c oxidase in Bacillus subtilis." Microbiology 150, no. 2 (February 1, 2004): 415–25. http://dx.doi.org/10.1099/mic.0.26691-0.

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The Gram-positive bacterium Bacillus subtilis contains two respiratory oxidases of the haem-copper superfamily: cytochrome aa 3, which is a quinol oxidase, and cytochrome caa 3, which is a cytochrome c oxidase. Cytochrome c oxidase uniquely contains a di-copper centre, CuA. B. subtilis CtaG is a membrane protein encoded by the same gene cluster as that which encodes the subunits of cytochrome c oxidase. The role of B. subtilis CtaG and orthologous proteins present in many other Gram-positive bacteria has remained unexplored. The sequence of CtaG is unrelated to that of CtaG/Cox11p of proteobacteria and eukaryotic cells. This study shows that B. subtilis CtaG is essential for the formation of active cytochrome caa 3 but is not required for assembly of the core subunits I and II with haem in the membrane and it has no role in the synthesis of active cytochrome aa 3. B. subtilis YpmQ, a homologue to Sco1p of eukaryotic cells, is also a membrane-bound cytochrome c oxidase-specific assembly factor. Properties of CtaG- and YpmQ-deficient mutants were compared. Cells lacking YpmQ showed a low cytochrome c oxidase activity and this defect was suppressed by the supplementation of the growth medium with copper ions. It has previously been proposed that YpmQ/Sco1p is involved in synthesis of the CuA centre. The results of this study are consistent with this proposal but the exact role of YpmQ in assembly of cytochrome c oxidase remains to be elucidated.

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9

Kopylchuk, H. P., and O. M. Voloshchuk. "Activity of respiratory chain cytochrome complexes and cytochromes content in the rat kidney mitochondria under different nutrients content in a diet." Ukrainian Biochemical Journal 95, no. 1 (April 26, 2023): 64–72. http://dx.doi.org/10.15407/ubj95.01.064.

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An important role in ensuring the functioning of the respiratory chain belongs to the cytochrome part, which includes complexes III (ubiquinol-cytochrome c oxidoreductase) and IV (cytochrome c oxidase). The key components of these enzymatic complexes are heme-containing cytochromes, the number of which depends on the balance of heme synthesis and catabolism. δ-Aminolevulinate synthase catalyzes the first step of the heme biosynthetic pathway, while heme oxygenase is the key enzyme of heme degradation. It is known that nutritional imbalances drive many risk factors for chronic kidney disease. That is why our research aimed to study the activity of ubiquinol-cytochrome c oxidoreductase and cytochrome oxidase complexes, the level of cytochromes a+a3, b, c, and c1, and the activity of key enzymes of heme metabolism in the mitochondria of rat kidneys under conditions of different content of protein and sucrose in animal diet. The obtained results showed a decreased activity of ubiquinol-cytochrome c oxidoreductase and cytochrome oxidase complexes and reduced levels of mitochondria cytochromes a+a3, b, c, and c1 in the kidney mitochondria under the conditions of nutrient imbalance, with the most pronounced changes found in animals kept on a low-protein/high-sucrose diet. A decrease in δ-aminolevulinate synthase activity with a simultaneous 2-fold increase in heme oxygenase activity was found in kidney mitochondria of animals kept on a low-protein/high-sucrose diet compared to those kept on full-value diet indicating an intensification of heme catabolism along with inhibition of its synthesis. The obtained results testify the energy imbalance under the conditions of low-protein/high-sucrose which in turn can lead to the progression of kidney injury. Keywords: cytochrome oxidase, cytochromes, heme oxygenase, nutrients, ubiquinol-cytochrome c oxidoreductase, δ-aminolevulinate synthase

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10

Shimokata, K., Y. Katayama, H. Shimada, and S. Yoshikawa. "hybrid cytochrome c oxidase." Seibutsu Butsuri 41, supplement (2001): S115. http://dx.doi.org/10.2142/biophys.41.s115_4.

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11

DiMAURO, SALVATORE, MASSIMO ZEVIANI, EDUARDO BONILLA, NEREO BRESOLIN, MASANORI NAKAGAWA, ARMAND F. MIRANDA, and MAURIZIO MOGGIO. "Cytochrome c oxidase deficiency." Biochemical Society Transactions 13, no. 4 (August 1, 1985): 651–53. http://dx.doi.org/10.1042/bst0130651.

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12

DiMauro, Salvatore, Anne Lombes, Hirofumi Nakase, Shuji Mita, Gian Maria Fabrizi, Eduardo Bonilla, Armand F. Miranda, Darryl C. DeVivo, and Eric A. Schon. "Cytochrome c Oxidase Deficiency." Pediatric Research 28, no. 5 (November 1990): 536–41. http://dx.doi.org/10.1203/00006450-199011000-00025.

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13

Antonini, G., M. Brunori, A. Colosimo, F. Malatesta, and P. Sarti. "Pulsed cytochrome c oxidase." Journal of Inorganic Biochemistry 23, no. 3-4 (March 1985): 289–93. http://dx.doi.org/10.1016/0162-0134(85)85037-6.

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14

Shoubridge, Eric A. "Cytochrome c oxidase deficiency." American Journal of Medical Genetics 106, no. 1 (2001): 46–52. http://dx.doi.org/10.1002/ajmg.1378.

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15

Brischigliaro, Michele, and Massimo Zeviani. "Cytochrome c oxidase deficiency." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1862, no. 1 (January 2021): 148335. http://dx.doi.org/10.1016/j.bbabio.2020.148335.

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16

Feissner, Robert E., Caroline S. Beckett, Jennifer A. Loughman, and Robert G. Kranz. "Mutations in Cytochrome Assembly and Periplasmic Redox Pathways in Bordetella pertussis." Journal of Bacteriology 187, no. 12 (June 15, 2005): 3941–49. http://dx.doi.org/10.1128/jb.187.12.3941-3949.2005.

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ABSTRACT Transposon mutagenesis of Bordetella pertussis was used to discover mutations in the cytochrome c biogenesis pathway called system II. Using a tetramethyl-p-phenylenediamine cytochrome c oxidase screen, 27 oxidase-negative mutants were isolated and characterized. Nine mutants were still able to synthesize c-type cytochromes and possessed insertions in the genes for cytochrome c oxidase subunits (ctaC, -D, and -E), heme a biosynthesis (ctaB), assembly of cytochrome c oxidase (sco2), or ferrochelatase (hemZ). Eighteen mutants were unable to synthesize all c-type cytochromes. Seven of these had transposons in dipZ (dsbD), encoding the transmembrane thioreduction protein, and all seven mutants were corrected for cytochrome c assembly by exogenous dithiothreitol, which was consistent with the cytochrome c cysteinyl residues of the CXXCH motif requiring periplasmic reduction. The remaining 11 insertions were located in the ccsBA operon, suggesting that with the appropriate thiol-reducing environment, the CcsB and CcsA proteins comprise the entire system II biosynthetic pathway. Antiserum to CcsB was used to show that CcsB is absent in ccsA mutants, providing evidence for a stable CcsA-CcsB complex. No mutations were found in the genes necessary for disulfide bond formation (dsbA or dsbB). To examine whether the periplasmic disulfide bond pathway is required for cytochrome c biogenesis in B. pertussis, a targeted knockout was made in dsbB. The DsbB− mutant makes holocytochromes c like the wild type does and secretes and assembles the active periplasmic alkaline phosphatase. A dipZ mutant is not corrected by a dsbB mutation. Alternative mechanisms to oxidize disulfides in B. pertussis are analyzed and discussed.

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Braun, Martin, and Linda Thöny-Meyer. "Cytochrome c Maturation and the Physiological Role of c-Type Cytochromes in Vibrio cholerae." Journal of Bacteriology 187, no. 17 (September 1, 2005): 5996–6004. http://dx.doi.org/10.1128/jb.187.17.5996-6004.2005.

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ABSTRACT Vibrio cholerae lives in different habitats, varying from aquatic ecosystems to the human intestinal tract. The organism has acquired a set of electron transport pathways for aerobic and anaerobic respiration that enable adaptation to the various environmental conditions. We have inactivated the V. cholerae ccmE gene, which is required for cytochrome c biogenesis. The resulting strain is deficient of all c-type cytochromes and allows us to characterize the physiological role of these proteins. Under aerobic conditions in rich medium, V. cholerae produces at least six c-type cytochromes, none of which is required for growth. Wild-type V. cholerae produces active fumarate reductase, trimethylamine N-oxide reductase, cbb 3 oxidase, and nitrate reductase, of which only the fumarate reductase does not require maturation of c-type cytochromes. The reduction of nitrate in the medium resulted in the accumulation of nitrite, which is toxic for the cells. This suggests that V. cholerae is able to scavenge nitrate from the environment only in the presence of other nitrite-reducing organisms. The phenotypes of cytochrome c-deficient V. cholerae were used in a transposon mutagenesis screening to search for additional genes required for cytochrome c maturation. Over 55,000 mutants were analyzed for nitrate reductase and cbb 3 oxidase activity. No transposon insertions other than those within the ccm genes for cytochrome c maturation and the dsbD gene, which encodes a disulphide bond reductase, were found. In addition, the role of a novel CcdA-like protein in cbb 3 oxidase assembly is discussed.

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18

Cross, Richard, David Lloyd, Robert K. Poole, and James W. B. Moir. "Enzymatic Removal of Nitric Oxide Catalyzed by Cytochrome c′ in Rhodobacter capsulatus." Journal of Bacteriology 183, no. 10 (May 15, 2001): 3050–54. http://dx.doi.org/10.1128/jb.183.10.3050-3054.2001.

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ABSTRACT Cytochrome c′ from Rhodobacter capsulatushas been shown to confer resistance to nitric oxide (NO). In this study, we demonstrated that the amount of cytochrome c′ synthesized for buffering of NO is insufficient to account for the resistance to NO but that the cytochrome-dependent resistance mechanism involves the catalytic breakdown of NO, under aerobic and anaerobic conditions. Even under aerobic conditions, the NO removal is independent of molecular oxygen, suggesting cytochrome c′ is a NO reductase. Indeed, we have measured the product of NO breakdown to be nitrous oxide (N2O), thus showing that cytochromec′ is behaving as a NO reductase. The increased resistance to NO conferred by cytochrome c′ is distinct from the NO reductase pathway that is involved in denitrification. Cytochromec′ is not required for denitrification, but it has a role in the removal of externally supplied NO. Cytochrome c′ synthesis occurs aerobically and anaerobically but is partly repressed under denitrifying growth conditions when other NO removal systems are operative. The inhibition of respiratory oxidase activity of R. capsulatus by NO suggests that one role for cytochromec′ is to maintain oxidase activity when both NO and O2 are present.

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19

Rogers, M. S., G. D. Jones, G. Antonini, M. T. Wilson, and M. Brunori. "Electron transfer from Phanerochaete chrysosporium cellobiose oxidase to equine cytochrome c and Pseudomonas aeruginosa cytochrome c-551." Biochemical Journal 298, no. 2 (March 1, 1994): 329–34. http://dx.doi.org/10.1042/bj2980329.

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The electron-transfer reactions of cellobiose oxidase (CBO) have been investigated by conventional and by rapid-scan stopped-flow spectroscopy at pH 6.0. Analysis of the absorbance/time/wavelength matrix by Singular Value Decomposition (SVD) confirms earlier studies showing that cellobiose rapidly reduces the flavin group (7.7 s-1; cellobiose, 100 microM) which in turn slowly (0.2 s-1) reduces the cytochrome b moiety. In the presence of CBO, cellobiose reduces cytochromes c in a reaction that does not depend on oxygen or superoxide. The rate limit for this process is independent of the source of the cytochromes c and is identical with the rate of cytochrome b reduction. Rapid-mixing experiments show that cytochrome b may donate electrons very rapidly to either mammalian cytochrome c or bacterial cytochrome c-551. The reactions were second-order (kc = 1.75 x 10(7) M-1 x s-1; kc-551 = 4.3 x 10(6) M-1 x s-1; pH 6.0, 21 degrees C and I0.064) and strongly ionic-strength (I)-dependent: kc decreasing with I and kc-551 increasing with I. These results suggest the electron-transfer site near cytochrome b bears a significant negative charge. Equilibrium gel chromatography confirms that CBO oxidase and positively charged mammalian cytochrome c make stable complexes. These results are discussed in terms of a model suggesting an electron-transfer role for cytochrome b in vivo, possibly connected with radical-mediated cellulose breakdown.

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Noor, Mohamed Radzi, and Tewfik Soulimane. "Structure of caa3 cytochrome c oxidase – a nature-made enzyme-substrate complex." Biological Chemistry 394, no. 5 (May 1, 2013): 579–91. http://dx.doi.org/10.1515/hsz-2012-0343.

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Abstract Aerobic respiration, the energetically most favorable metabolic reaction, depends on the action of terminal oxidases that include cytochrome c oxidases. The latter forms a part of the heme-copper oxidase superfamily and consists of three different families (A, B, and C types). The crystal structures of all families have now been determined, allowing a detailed structural comparison from evolutionary and functional perspectives. The A2-type oxidase, exemplified by the Thermus thermophilus caa3 oxidase, contains the substrate cytochrome c covalently bound to the enzyme complex. In this article, we highlight the various features of caa3 enzyme and provide a discussion of their importance, including the variations in the proton and electron transfer pathways.

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Balodite, Elina, Inese Strazdina, Nina Galinina, Samantha McLean, Reinis Rutkis, Robert K. Poole, and Uldis Kalnenieks. "Structure of the Zymomonas mobilis respiratory chain: oxygen affinity of electron transport and the role of cytochrome c peroxidase." Microbiology 160, no. 9 (September 1, 2014): 2045–52. http://dx.doi.org/10.1099/mic.0.081612-0.

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The genome of the ethanol-producing bacterium Zymomonas mobilis encodes a bd-type terminal oxidase, cytochrome bc 1 complex and several c-type cytochromes, yet lacks sequences homologous to any of the known bacterial cytochrome c oxidase genes. Recently, it was suggested that a putative respiratory cytochrome c peroxidase, receiving electrons from the cytochrome bc 1 complex via cytochrome c 552, might function as a peroxidase and/or an alternative oxidase. The present study was designed to test this hypothesis, by construction of a cytochrome c peroxidase mutant (Zm6-perC), and comparison of its properties with those of a mutant defective in the cytochrome b subunit of the bc 1 complex (Zm6-cytB). Disruption of the cytochrome c peroxidase gene (ZZ60192) caused a decrease of the membrane NADH peroxidase activity, impaired the resistance of growing culture to exogenous hydrogen peroxide and hampered aerobic growth. However, this mutation did not affect the activity or oxygen affinity of the respiratory chain, or the kinetics of cytochrome d reduction. Furthermore, the peroxide resistance and membrane NADH peroxidase activity of strain Zm6-cytB had not decreased, but both the oxygen affinity of electron transport and the kinetics of cytochrome d reduction were affected. It is therefore concluded that the cytochrome c peroxidase does not terminate the cytochrome bc 1 branch of Z. mobilis, and that it is functioning as a quinol peroxidase.

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Tsukihara, Tomitake. "Crystallographic studies of cytochrome c and cytochrome c oxidase." Journal of Biochemistry 171, no. 1 (October 26, 2021): 13–15. http://dx.doi.org/10.1093/jb/mvab118.

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23

Crum, John, Kenneth J. Gruys, and Terrence G. Frey. "Undecagold labeling of cytochrome c oxidase dimer crystals." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 278–79. http://dx.doi.org/10.1017/s0424820100085691.

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Cytochrome c oxidase (E.C. 1.9.3.1.) is an integral inner mitochondrial membrane protein, and is the terminal electron acceptor whereby cytochrome c (reduced by ubiquinol cytochrome c oxidoreductase) is oxidized and molecular oxygen is reduced producing water. When isolated mitochondria are treated with detergents, the other proteins and most of the lipids are extracted leaving membranous cytochrome c oxidase. Depending on the amounts and types of detergents used the cytochrome c oxidase molecules may form two-dimensional crystals composed of monomers or of dimers. These two-dimensional crystals are suitable for crystallographic image processing procedures. Recently the three-dimensional structure of cytochrome c oxidase in dimer crystals has been reported to a resolution of 20 Å. Though much work has been done, the location of the cytochrome c binding site on cytochrome c oxidase has not been determined.

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Hasinoff, B. B., and J. P. Davey. "The iron(III)-adriamycin complex inhibits cytochrome c oxidase before its inactivation." Biochemical Journal 250, no. 3 (March 15, 1988): 827–34. http://dx.doi.org/10.1042/bj2500827.

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Cytochrome c oxidase was found to be competitively inhibited by a complex formed between Fe3+ and the cardiotoxic antitumour drug adriamycin (doxorubicin) with an inhibition constant, Ki, of 12 microM. This competitive inhibition precedes the slower Fe3+-adriamycin induced inactivation of cytochrome c oxidase. In strong contrast with this result, free adriamycin was not observed to either inhibit or inactivate cytochrome c oxidase (Ki greater than 3 mM). Since, typically, polycations are known to inhibit cytochrome c oxidase, the competitive inhibition displayed by the Fe3+-adriamycin complex may also result from its polycationic character. Cytochrome c oxidase was also inhibited by pentan-1-ol (Ki 13 mM), and kinetic studies carried out in the presence of both inhibitors demonstrated that the Fe3+-adriamycin complex and pentan-1-ol are mutually exclusive inhibitors of cytochrome c oxidase. The inhibitor pentan-1-ol was also effective in preventing the slow inactivation of cytochrome c oxidase induced by Fe3+-adriamycin, presumably by blocking its binding to the enzyme. It is postulated that the slow inactivation of cytochrome c oxidase occurs when reactive radical species are produced while the Fe3+-adriamycin is complexed to cytochrome c oxidase in an enzyme-inhibitor complex. The Fe3+-adriamycin-induced inactivation of cytochrome c oxidase may be, in part, responsible for the cardiotoxicity of adriamycin.

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Kalia, Nitin P., Erik J. Hasenoehrl, Nurlilah B. Ab Rahman, Vanessa H. Koh, Michelle L. T. Ang, Dannah R. Sajorda, Kiel Hards, et al. "Exploiting the synthetic lethality between terminal respiratory oxidases to kill Mycobacterium tuberculosis and clear host infection." Proceedings of the National Academy of Sciences 114, no. 28 (June 26, 2017): 7426–31. http://dx.doi.org/10.1073/pnas.1706139114.

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The recent discovery of small molecules targeting the cytochrome bc1:aa3 in Mycobacterium tuberculosis triggered interest in the terminal respiratory oxidases for antituberculosis drug development. The mycobacterial cytochrome bc1:aa3 consists of a menaquinone:cytochrome c reductase (bc1) and a cytochrome aa3-type oxidase. The clinical-stage drug candidate Q203 interferes with the function of the subunit b of the menaquinone:cytochrome c reductase. Despite the affinity of Q203 for the bc1:aa3 complex, the drug is only bacteriostatic and does not kill drug-tolerant persisters. This raises the possibility that the alternate terminal bd-type oxidase (cytochrome bd oxidase) is capable of maintaining a membrane potential and menaquinol oxidation in the presence of Q203. Here, we show that the electron flow through the cytochrome bd oxidase is sufficient to maintain respiration and ATP synthesis at a level high enough to protect M. tuberculosis from Q203-induced bacterial death. Upon genetic deletion of the cytochrome bd oxidase-encoding genes cydAB, Q203 inhibited mycobacterial respiration completely, became bactericidal, killed drug-tolerant mycobacterial persisters, and rapidly cleared M. tuberculosis infection in vivo. These results indicate a synthetic lethal interaction between the two terminal respiratory oxidases that can be exploited for anti-TB drug development. Our findings should be considered in the clinical development of drugs targeting the cytochrome bc1:aa3, as well as for the development of a drug combination targeting oxidative phosphorylation in M. tuberculosis.

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Winterle, John S., and Ólöf Einarsdóttir. "Photoreactions of Cytochrome c Oxidase." Photochemistry and Photobiology 82, no. 3 (2006): 711. http://dx.doi.org/10.1562/2005-09-14-ra-684.

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SHINZAWA-ITOH, Kyoko. "Crystallization of Cytochrome c Oxidase." Nihon Kessho Gakkaishi 33, no. 5 (1991): 284–89. http://dx.doi.org/10.5940/jcrsj.33.284.

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BISSON, ROBERTO, and GIAMPIETRO SCHIAVO. "Slime Mold Cytochrome c Oxidase." Annals of the New York Academy of Sciences 550, no. 1 Cytochrome Ox (December 1988): 325–36. http://dx.doi.org/10.1111/j.1749-6632.1988.tb35347.x.

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29

Rak, Malgorzata, Paule Bénit, Dominique Chrétien, Juliette Bouchereau, Manuel Schiff, Riyad El-Khoury, Alexander Tzagoloff, and Pierre Rustin. "Mitochondrial cytochrome c oxidase deficiency." Clinical Science 130, no. 6 (February 4, 2016): 393–407. http://dx.doi.org/10.1042/cs20150707.

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Cytochrome oxidase defects are multiform diseases and despite major progress made in elucidating their molecular basis, we are still waiting for an efficient treatment. We discuss the cause of this discrepancy stressing the foremost questions that remain to be solved.

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30

Yoshikawa, Shinya. "Beef heart cytochrome c oxidase." Current Opinion in Structural Biology 7, no. 4 (August 1997): 574–79. http://dx.doi.org/10.1016/s0959-440x(97)80124-8.

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Khalimonchuk, Oleh, and Gerhard Rödel. "Biogenesis of cytochrome c oxidase." Mitochondrion 5, no. 6 (December 2005): 363–88. http://dx.doi.org/10.1016/j.mito.2005.08.002.

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32

Li, Ying, Amanda Hopper, Tim Overton, Derrick J. P. Squire, Jeffrey Cole, and Nicholas Tovell. "Organization of the Electron Transfer Chain to Oxygen in the Obligate Human Pathogen Neisseria gonorrhoeae: Roles for Cytochromes c4 and c5, but Not Cytochrome c2, in Oxygen Reduction." Journal of Bacteriology 192, no. 9 (February 12, 2010): 2395–406. http://dx.doi.org/10.1128/jb.00002-10.

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ABSTRACT Although Neisseria gonorrhoeae is a prolific source of eight c-type cytochromes, little is known about how its electron transfer pathways to oxygen are organized. In this study, the roles in the respiratory chain to oxygen of cytochromes c 2, c 4, and c 5, encoded by the genes cccA, cycA, and cycB, respectively, have been investigated. Single mutations in genes for either cytochrome c 4 or c 5 resulted in an increased sensitivity to growth inhibition by excess oxygen and small decreases in the respiratory capacity of the parent, which were complemented by the chromosomal integration of an ectopic, isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible copy of the cycA or cycB gene. In contrast, a cccA mutant reduced oxygen slightly more rapidly than the parent, suggesting that cccA is expressed but cytochrome c 2 is not involved in electron transfer to cytochrome oxidase. The deletion of cccA increased the sensitivity of the cycB mutant to excess oxygen but decreased the sensitivity of the cycA mutant. Despite many attempts, a double mutant defective in both cytochromes c 4 and c 5 could not be isolated. However, a strain with the ectopically encoded, IPTG-inducible cycB gene with deletions in both cycA and cycB was constructed: the growth and survival of this strain were dependent upon the addition of IPTG, so gonococcal survival is dependent upon the synthesis of either cytochrome c 4 or c 5. These results define the gonococcal electron transfer chain to oxygen in which cytochromes c 4 and c 5, but not cytochrome c 2, provide alternative pathways for electron transfer from the cytochrome bc 1 complex to the terminal oxidase cytochrome cbb 3.

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33

Makino, Yoshio, Masayuki Ichimura, Yoshinori Kawagoe, and Seiichi Oshita. "Cytochrome c Oxidase as a Cause of Variation in Oxygen Uptake Rates Among Vegetables." Journal of the American Society for Horticultural Science 132, no. 2 (March 2007): 239–45. http://dx.doi.org/10.21273/jashs.132.2.239.

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The effect of cytochrome c oxidase, the terminal oxidase in the respiratory chain, on O2 uptake by vegetables was investigated. Broccoli florets (Brassica oleracea L. var. italica Plenck), spinach leaves (Spinacia oleracea L.), and onion bulbs (Allium cepa L.), which were expected to show rapid, moderate, and slow O2 uptake rates, respectively, were used in the current study. The order of O2 uptake rate measured by a closed method with a gas chromatograph was broccoli florets > spinach leaves > onion bulbs. Cytochrome c oxidase activity of mitochondrial preparations from onion bulbs was lower than that of the other vegetables, as was the O2 uptake rate. The higher O2 uptake rate of broccoli florets compared to spinach leaves was caused by higher cytochrome c oxidase activity of the floral buds. Grayscale luminance was used to determine the extent and distribution of staining in the tissues due to cytochrome c oxidase activity. Active O2 uptake by floral buds of broccoli florets was caused by the high concentration of cytochrome c oxidase in the pistil and petal. The absorbance of stems of broccoli florets at 823 nm, possibly derived from absorption by copper in cytochrome c oxidase, was higher than that of onion scale leaves, which agreed with the results of cytochrome c oxidase staining. We concluded that cytochrome c oxidase contributed to the O2 uptake rate by vegetables and that cytochrome c oxidase was one of the important causes for variation in O2 uptake rates among vegetables.

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34

Gnaiger, E., and A. V. Kuznetsov. "Mitochondrial respiration at low levels of oxygen and cytochrome c." Biochemical Society Transactions 30, no. 2 (April 1, 2002): 252–58. http://dx.doi.org/10.1042/bst0300252.

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In the intracellular microenvironment of active muscle tissue, high rates of respiration are maintained at near-limiting oxygen concentrations. The respiration of isolated heart mitochondria is a hyperbolic function of oxygen concentration and half-maximal rates were obtained at 0.4 and 0.7 μM O2 with substrates for the respiratory chain (succinate) and cytochrome c oxidase [N, N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD) + ascorbate] respectively at 30 °C and with maximum ADP stimulation (State 3). The respiratory response of cytochrome c-depleted mitoplasts to external cytochrome c was biphasic with TMPD, but showed a monophasic hyperbolic function with succinate. Half-maximal stimulation of respiration was obtained at 0.4 μM cytochrome c, which was nearly identical to the high-affinity K'm for cytochrome c of cytochrome c oxidase supplied with TMPD. The capacity of cytochrome c oxidase in the presence of TMPD was 2-fold higher than the capacity of the respiratory chain with succinate, measured at environmental normoxic levels. This apparent excess capacity, however, is significantly decreased under physiological intracellular oxygen conditions and declines steeply under hypoxic conditions. Similarly, the excess capacity of cytochrome c oxidase declines with progressive cytochrome c depletion. The flux control coefficient of cytochrome c oxidase, therefore, increases as a function of substrate limitation of oxygen and cytochrome c, which suggests a direct functional role for the apparent excess capacity of cytochrome c oxidase in hypoxia and under conditions of intracellular accumulation of cytochrome c after its release from mitochondria.

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35

Crinson, M., and P. Nicholls. "Routes of electron transfer in beef heart cytochrome c oxidase: is there a unique pathway used by all reductants?" Biochemistry and Cell Biology 70, no. 5 (May 1, 1992): 301–8. http://dx.doi.org/10.1139/o92-047.

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Cytochrome c oxidase oxidizes several hydrogen donors, including TMPD (N,N,N′,N′-tetramethyl-p-phenylenediamine) and DMPT (2-amino-6,7-dimethyl-5,6,7,8-tetrahydropterine), in the absence of the physiological substrate cytochrome c. Maximal enzyme turnovers with TMPD and DMPT alone are rather less than with cytochrome c, but much greater than previously reported if extrapolated to high reductant levels and (or) to 100% reduction of cytochrome a in the steady state. The presence of cytochrome c is, therefore, not necessary for substantial intramolecular electron transfer to occur in the oxidase. A direct bimolecular reduction of cytochrome a by TMPD is sufficient to account for the turnover of the enzyme. CuA may not be an essential component of the TMPD oxidase pathway. DMPT oxidation seems to occur more rapidly than the DMPT – cytochrome a reduction rate and may therefore imply mediation of CuA. Both "resting" and "pulsed" oxidases contain rapid-turnover and slow-turnover species, as determined by aerobic steady-state reduction of cytochrome a by TMPD. Only the "rapid" fraction (≈70% of the total with resting and ≈85% of the total with pulsed) is involved in turnover. We conclude that electron transfer to the a3CuB binuclear centre can occur either from cytochrome a or CuA, depending upon the redox state of the binuclear centre. Under steady-state conditions, cytochrome a and CuA may not always be in rapid equilibrium. Rapid enzyme turnover by either natural or artificial substrates may require reduction of both and two pathways of electron transfer to the a3CuB centre.Key words: cytochrome c oxidase, cytochrome a, respiration, cyanide, stopped flow.

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36

Peters, Annette, Carmen Kulajta, Grzegorz Pawlik, Fevzi Daldal, and Hans-Georg Koch. "Stability of the cbb3-Type Cytochrome Oxidase Requires Specific CcoQ-CcoP Interactions." Journal of Bacteriology 190, no. 16 (June 13, 2008): 5576–86. http://dx.doi.org/10.1128/jb.00534-08.

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ABSTRACT Cytochrome cbb 3-type oxidases are members of the heme copper oxidase superfamily and are composed of four subunits. CcoN contains the heme b-CuB binuclear center where oxygen is reduced, while CcoP and CcoO are membrane-bound c-type cytochromes thought to channel electrons from the donor cytochrome into the binuclear center. Like many other bacterial members of this superfamily, the cytochrome cbb 3-type oxidase contains a fourth, non-cofactor-containing subunit, which is termed CcoQ. In the present study, we analyzed the role of CcoQ on the stability and activity of Rhodobacter capsulatus cbb 3-type oxidase. Our data showed that CcoQ is a single-spanning membrane protein with a Nout-Cin topology. In the absence of CcoQ, cbb 3-type oxidase activity is significantly reduced, irrespective of the growth conditions. Blue native polyacrylamide gel electrophoresis analyses revealed that the lack of CcoQ specifically impaired the stable recruitment of CcoP into the cbb 3-type oxidase complex. This suggested a specific CcoQ-CcoP interaction, which was confirmed by chemical cross-linking. Collectively, our data demonstrated that in R. capsulatus CcoQ was required for optimal cbb 3-type oxidase activity because it stabilized the interaction of CcoP with the CcoNO core complex, leading subsequently to the formation of the active 230-kDa cbb 3-type oxidase complex.

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37

Flores-Encarnación, M., M. Contreras-Zentella, L. Soto-Urzua, G. R. Aguilar, B. E. Baca, and J. E. Escamilla. "The Respiratory System and Diazotrophic Activity ofAcetobacter diazotrophicus PAL5." Journal of Bacteriology 181, no. 22 (November 15, 1999): 6987–95. http://dx.doi.org/10.1128/jb.181.22.6987-6995.1999.

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ABSTRACT The characteristics of the respiratory system of Acetobacter diazotrophicus PAL5 were investigated. Increasing aeration (from 0.5 to 4.0 liters of air min−1 liter of medium−1) had a strong positive effect on growth and on the diazotrophic activity of cultures. Cells obtained from well-aerated and diazotrophically active cultures possessed a highly active, membrane-bound electron transport system with dehydrogenases for NADH, glucose, and acetaldehyde as the main electron donors. Ethanol, succinate, and gluconate were also oxidized but to only a minor extent. Terminal cytochrome c oxidase-type activity was poor as measured by reducedN,N,N,N′-tetramethyl-p-phenylenediamine, but quinol oxidase-type activity, as measured by 2,3,5,6-tetrachloro-1,4-benzenediol, was high. Spectral and high-pressure liquid chromatography analysis of membranes revealed the presence of cytochrome ba as a putative oxidase in cells obtained from diazotrophically active cultures. Cells were also rich inc-type cytochromes; four bands of high molecular mass (i.e., 67, 56, 52, and 45 kDa) were revealed by a peroxidase activity stain in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. KCN inhibition curves of respiratory oxidase activities were biphasic, with a highly resistant component. Treatment of membranes with 0.2% Triton X-100 solubilized c-type cytochromes and resulted in a preparation that was significantly more sensitive to cyanide. Repression of diazotrophic activity in well-aerated cultures by 40 mM (NH4)2SO4 caused a significant decrease of the respiratory activities. It is noteworthy that the levels of glucose dehydrogenase and putative oxidaseba decreased 6.8- and 10-fold, respectively. In these cells, a bd-type cytochrome seems to be the major terminal oxidase. Thus, it would seem that glucose dehydrogenase and cytochrome ba are key components of the respiratory system of A. diazotrophicus during aerobic diazotrophy.

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38

Alleyne, Trevor, Damian Ashe, and Emmanuel Iwuoha. "Serum cytochrome c detection using a cytochrome c oxidase biosensor." Biotechnology and Applied Biochemistry 46, no. 4 (April 1, 2007): 185. http://dx.doi.org/10.1042/ba20060103.

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39

Pan, Lian Ping, James T. Hazzard, Jian Lin, Gordon Tollin, and Sunney I. Chan. "The electron input to cytochrome c oxidase from cytochrome c." Journal of the American Chemical Society 113, no. 15 (July 1991): 5908–10. http://dx.doi.org/10.1021/ja00015a081.

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40

Michel, B., A. G. Mauk, and H. R. Bosshard. "Binding and oxidation of mutant cytochromes c by cytochrome-c oxidase." FEBS Letters 243, no. 2 (January 30, 1989): 149–52. http://dx.doi.org/10.1016/0014-5793(89)80118-8.

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41

Jiménez de Bagüés, Maria Pilar, Séverine Loisel-Meyer, Jean-Pierre Liautard, and Véronique Jubier-Maurin. "Different Roles of the Two High-Oxygen-Affinity Terminal Oxidases of Brucella suis: Cytochrome c Oxidase, but Not Ubiquinol Oxidase, Is Required for Persistence in Mice." Infection and Immunity 75, no. 1 (November 13, 2006): 531–35. http://dx.doi.org/10.1128/iai.01185-06.

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ABSTRACT The survival of Brucella suis mutant strains in mice demonstrated different roles of the two high-oxygen-affinity terminal oxidases. The cbb3-type cytochrome c oxidase was essential for chronic infection in oxygen-deficient organs. Lack of the cytochrome bd ubiquinol oxidase led to hypervirulence of bacteria, which could rely on nitrite accumulation inhibiting the inducible nitric oxide synthase of the host.

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42

Muntyan, Maria S., Dmitry A. Cherepanov, Anssi M. Malinen, Dmitry A. Bloch, Dimitry Y. Sorokin, Inna I. Severina, Tatiana V. Ivashina, Reijo Lahti, Gerard Muyzer, and Vladimir P. Skulachev. "Cytochrome cbb3 of Thioalkalivibrio is a Na+-pumping cytochrome oxidase." Proceedings of the National Academy of Sciences 112, no. 25 (June 8, 2015): 7695–700. http://dx.doi.org/10.1073/pnas.1417071112.

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Cytochrome c oxidases (Coxs) are the basic energy transducers in the respiratory chain of the majority of aerobic organisms. Coxs studied to date are redox-driven proton-pumping enzymes belonging to one of three subfamilies: A-, B-, and C-type oxidases. The C-type oxidases (cbb3 cytochromes), which are widespread among pathogenic bacteria, are the least understood. In particular, the proton-pumping machinery of these Coxs has not yet been elucidated despite the availability of X-ray structure information. Here, we report the discovery of the first (to our knowledge) sodium-pumping Cox (Scox), a cbb3 cytochrome from the extremely alkaliphilic bacterium Thioalkalivibrio versutus. This finding offers clues to the previously unknown structure of the ion-pumping channel in the C-type Coxs and provides insight into the functional properties of this enzyme.

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43

Lesnefsky, Edward J., Qun Chen, Thomas J. Slabe, Maria S. K. Stoll, Paul E. Minkler, Medhat O. Hassan, Bernard Tandler, and Charles L. Hoppel. "Ischemia, rather than reperfusion, inhibits respiration through cytochrome oxidase in the isolated, perfused rabbit heart: role of cardiolipin." American Journal of Physiology-Heart and Circulatory Physiology 287, no. 1 (July 2004): H258—H267. http://dx.doi.org/10.1152/ajpheart.00348.2003.

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Ischemia and reperfusion result in mitochondrial dysfunction, with decreases in oxidative capacity, loss of cytochrome c, and generation of reactive oxygen species. During ischemia of the isolated perfused rabbit heart, subsarcolemmal mitochondria, located beneath the plasma membrane, sustain a loss of the phospholipid cardiolipin, with decreases in oxidative metabolism through cytochrome oxidase and the loss of cytochrome c. We asked whether additional injury to the distal electron chain involving cardiolipin with loss of cytochrome c and cytochrome oxidase occurs during reperfusion. Reperfusion did not lead to additional damage in the distal electron transport chain. Oxidation through cytochrome oxidase and the content of cytochrome c did not further decrease during reperfusion. Thus injury to cardiolipin, cytochrome c, and cytochrome oxidase occurs during ischemia rather than during reperfusion. The ischemic injury leads to persistent defects in oxidative function during the early reperfusion period. The decrease in cardiolipin content accompanied by persistent decrements in the content of cytochrome c and oxidation through cytochrome oxidase is a potential mechanism of additional myocyte injury during reperfusion.

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Daldal, Fevzi, Sevnur Mandaci, Christine Winterstein, Hannu Myllykallio, Kristen Duyck, and Davide Zannoni. "Mobile Cytochrome c2 and Membrane-Anchored Cytochrome cy Are Both Efficient Electron Donors to the cbb3- andaa3-Type Cytochrome cOxidases during Respiratory Growth of Rhodobacter sphaeroides." Journal of Bacteriology 183, no. 6 (March 15, 2001): 2013–24. http://dx.doi.org/10.1128/jb.183.6.2013-2024.2001.

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ABSTRACT We have recently established that the facultative phototrophic bacterium Rhodobacter sphaeroides, like the closely relatedRhodobacter capsulatus species, contains both the previously characterized mobile electron carrier cytochromec 2 (cyt c 2) and the more recently discovered membrane-anchored cytc y. However, R. sphaeroides cytc y, unlike that of R. capsulatus, is unable to function as an efficient electron carrier between the photochemical reaction center and the cyt bc 1complex during photosynthetic growth. Nonetheless, R. sphaeroides cyt c y can act at least in R. capsulatus as an electron carrier between the cytbc 1 complex and thecbb 3-type cyt c oxidase (cbb 3-Cox) to support respiratory growth. Since R. sphaeroides harbors both acbb 3-Cox and anaa 3-type cyt c oxidase (aa 3-Cox), we examined whetherR. sphaeroides cyt c y can act as an electron carrier to either or both of these respiratory terminal oxidases. R. sphaeroides mutants which lacked either cyt c 2 or cyt c y and either the aa 3-Cox or thecbb 3-Cox were obtained. These double mutants contained linear respiratory electron transport pathways between the cyt bc 1 complex and the cytc oxidases. They were characterized with respect to growth phenotypes, contents of a-, b-, andc-type cytochromes, cyt c oxidase activities, and kinetics of electron transfer mediated by cytc 2 or cyt c y. The findings demonstrated that both cyt c 2 and cytc y are able to carry electrons efficiently from the cyt bc 1 complex to either thecbb 3-Cox or theaa 3-Cox. Thus, no dedicated electron carrier for either of the cyt c oxidases is present in R. sphaeroides. However, under semiaerobic growth conditions, a larger portion of the electron flow out of the cytbc 1 complex appears to be mediated via the cytc 2-to-cbb 3-Coxand cytcy -to-cbb 3-Coxsubbranches. The presence of multiple electron carriers and cytc oxidases with different properties that can operate concurrently reveals that the respiratory electron transport pathways of R. sphaeroides are more complex than those ofR. capsulatus.

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45

Jackson, Rachel J., Karen T. Elvers, Lucy J. Lee, Mark D. Gidley, Laura M. Wainwright, James Lightfoot, Simon F. Park, and Robert K. Poole. "Oxygen Reactivity of Both Respiratory Oxidases in Campylobacter jejuni: the cydAB Genes Encode a Cyanide-Resistant, Low-Affinity Oxidase That Is Not of the Cytochrome bd Type." Journal of Bacteriology 189, no. 5 (December 15, 2006): 1604–15. http://dx.doi.org/10.1128/jb.00897-06.

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ABSTRACT The microaerophilic bacterium Campylobacter jejuni is a significant food-borne pathogen and is predicted to possess two terminal respiratory oxidases with unknown properties. Inspection of the genome reveals an operon (cydAB) apparently encoding a cytochrome bd-like oxidase homologous to oxidases in Escherichia coli and Azotobacter vinelandii. However, C. jejuni cells lacked all spectral signals characteristic of the high-spin hemes b and d of these oxidases. Mutation of the cydAB operon of C. jejuni did not have a significant effect on growth, but the mutation reduced formate respiration and the viability of cells cultured in 5% oxygen. Since cyanide resistance of respiration was diminished in the mutant, we propose that C. jejuni CydAB be renamed CioAB (cyanide-insensitive oxidase), as in Pseudomonas aeruginosa. We measured the oxygen affinity of each oxidase, using a highly sensitive assay that exploits globin deoxygenation during respiration-catalyzed oxygen uptake. The CioAB-type oxidase exhibited a relatively low affinity for oxygen (Km = 0.8 μM) and a V max of >20 nmol/mg/s. Expression of cioAB was elevated fivefold in cells grown at higher rates of oxygen provision. The alternative, ccoNOQP-encoded cyanide-sensitive oxidase, expected to encode a cytochrome cb′-type enzyme, plays a major role in the microaerobic respiration of C. jejuni, since it appeared to be essential for viability and exhibited a much higher oxygen affinity, with a Km value of 40 nM and a V max of 6 to 9 nmol/mg/s. Low-temperature photodissociation spectrophotometry revealed that neither oxidase has ligand-binding activity typical of the heme-copper oxidase family. These data are consistent with cytochrome oxidation during photolysis at low temperatures.

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46

Taha, Taher M., Fumiaki Takeuchi, and Tsuyoshi Sugio. "Reduction of Cytochrome c by Tetrathionate in the Presence of Tetrathionate Hydrolase Purified from Sulfur-Grown Acidithiobacillus Ferrooxidans ATCC 23270." Advanced Materials Research 71-73 (May 2009): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.243.

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It is mysterious that, when A. ferrooxidans ATCC 23270 cells grow on elemental sulfur, they have high iron oxidase activity comparable to that of iron-grown cells as well as high activities of sulfide:ferric ion oxidoreductase (SFORase) and tetrathionate hydrolase. To clarify this interesting phenomenon, cytochrome c and tetrathionate hydrolase were purified from sulfur-grown A. ferrooxidans cells using ammonium sulfate precipitation, Phenyl column chromatography, and SuperdexTM 75 and Sephadex G-100 size exclusion column chromatographies. The purified cytochrome c was reduced by tetrathionate in the presence of purified tetrathionate hydrolase, but not in the absence of the enzyme. When the partially purified cytochrome c fraction containing aa3-type cytochrome oxidase was used, both cytochrome c and aa3-type cytochrome oxidase were reduced by tetrathionate in the presence of purified tetrathionate hydrolase. These results indicate that tetrathionate in the presence of tetrathionate hydrolase can reduce iron oxidase enzyme system containing cytochrome c and aa3-type cytochrome oxidase as tetrathionate hydrolase decomposes tetrathionate to produce thiosulfate, elemental sulfur, and sulfate; and the formed thiosulfate can chemically reduce cytochrome c and Fe3+.

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47

Rich, Peter R. "Mitochondrial cytochrome c oxidase: catalysis, coupling and controversies." Biochemical Society Transactions 45, no. 3 (June 15, 2017): 813–29. http://dx.doi.org/10.1042/bst20160139.

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Mitochondrial cytochrome c oxidase is a member of a diverse superfamily of haem–copper oxidases. Its mechanism of oxygen reduction is reviewed in terms of the cycle of catalytic intermediates and their likely chemical structures. This reaction cycle is coupled to the translocation of protons across the inner mitochondrial membrane in which it is located. The likely mechanism by which this occurs, derived in significant part from studies of bacterial homologues, is presented. These mechanisms of catalysis and coupling, together with current alternative proposals of underlying mechanisms, are critically reviewed.

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48

Voloshchuk, O. N., M. M. Marchenko, and M. C. Mudrak. "The change in the structural and functional organization of the guerin's carcinoma cytochrome part of respiratory chain in tumor carriers in the conditions of preliminary low-level irradiation." Biomeditsinskaya Khimiya 58, no. 6 (2012): 684–90. http://dx.doi.org/10.18097/pbmc20125806684.

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The effect of low-level irradiation of tumor-bearing rats on the structural and functional organization of the cytochrome part of respiratory chain of mitochondria isolated from Guerin's carcinoma has been investigated.The maximal reduction in the mitochondrial cytochromes a, b and c content was observed at the terminal stage of Guerin's carcinoma. A low-level irradiation during initial stages of oncogenesis produced opposite changes in the mitochondrial cytochrome content.The possible mechanism of mitochondrial haem-containing cytochromes content reduction may be attributed to impairment in their formation caused by inhibition of the key enzyme of haem synthesis, 5-aminolevulinate synthase.The determined changes of the mitochondrial cytochromes quantitative content were accompanied by decreased activity of cytochrome oxidase. The preliminary low-level irradiation of the tumor-bearing animals produced further reduction in the cytochrome oxidase activity observed in all experimental periods.

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Forsha, D., C. Church, P. Wazny, and R. O. Poyton. "Structure and function of Pet100p, a molecular chaperone required for the assembly of cytochrome c oxidase in Saccharomyces cerevisiae." Biochemical Society Transactions 29, no. 4 (August 1, 2001): 436–41. http://dx.doi.org/10.1042/bst0290436.

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The assembly of cytochrome c oxidase in the inner mitochondrial membranes of eukaryotic cells requires the protein products of a large number of nuclear genes. In yeast, some of these act globally and affect the assembly of several respiratory-chain protein complexes, whereas others act in a cytochrome c oxidase-specific fashion. Many of these yeast proteins have human counterparts, which when mutated lead to energy-related diseases. One of these proteins, Pet100p, is a novel molecular chaperone that functions to incorporate a subcomplex containing cytochrome c oxidase subunits VII, VIIa and VIII into holo-(cytochrome c oxidase). Here we report the topological disposition of Pet100p in the inner mitochondrial membrane and show that its C-terminal domain is essential for its function as a cytochrome c oxidase-specific ‘assembly facilitator’.

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50

Brown, Guy C., and Vilmante Borutaite. "Nitric oxide, cytochrome c and mitochondria." Biochemical Society Symposia 66 (September 1, 1999): 17–25. http://dx.doi.org/10.1042/bss0660017.

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Nitric oxide (NO) and its derivative, peroxynitrite (ONOO-), inhibit mitochondrial respiration, and this inhibition may contribute to both the physiological and cytotoxic actions of NO. Nanomolar concentrations of NO rapidly and reversibly inhibited cytochrome oxidase in competition with oxygen, as shown with isolated cytochrome oxidase, mitochondria, brain nerve terminals and cells. Cultured astrocytes and macrophages activated (by cytokines and endotoxin) to express the inducible form of NO synthase produced up to 1 μM NO, and inhibited their own respiration and that of co-incubated cells via reversible NO inhibition of cytochrome oxidase. NO-induced inhibition of respiration in brain nerve terminals resulted in rapid glutamate release, which might contribute to the neurotoxicity of NO. NO inhibition of cytochrome oxidase is reversible; however, incubation of cells with NO donors for 4 hours resulted in an inhibition of complex I, which was reversible by light and thiol reagents and may be due to nitrosylation of thiols in complex I. NO also caused the acute inhibition of catalase, stimulation of hydrogen peroxide production by mitochondria, and reaction with hydrogen peroxide on superoxide dismutase to produce peroxynitrite. Peroxynitrite inhibited complexes I, II and V (the ATP synthase), aconitase, creatine kinase, and increases the proton leak in isolated mitochondria. Peroxynitrite also caused opening of the permeability transition pore, resulting in the release of cytochrome c, which might then trigger apoptosis. Hypoxia/ischaemia also resulted in an acute reversible inhibition of cytochrome oxidase. Heart ischaemia caused the release of cytochrome c from mitochondria into the cytosol, and at the same time caspase-3-like-protease activity was activated in the cytoplasm. Addition of cytochrome c to non-ischaemic cytosol also caused activation of this protease activity, suggesting that caspase activation and consequent apoptosis is at least partly a result of this cytochrome c release.

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Journal articles on the topic 'Cytochrome C oxidase'

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