Comparison of yeast and beef cytochrome c oxidases. Kinetics and binding of horse, fungal, and Euglena cytochromes c.

The amino acid sequences of the cytochromes c-551 from three species of Pseudomonas have been determined. Each resembles the protein from Pseudomonas strain P6009 (now known to be Pseudomonas aeruginosa, not Pseudomonas fluorescens) in containing 82 amino acids in a single peptide chain, with a haem group covalently attached to cysteine residues 12 and 15. In all four sequences 43 residues are identical. Although by bacteriological criteria the organisms are closely related, the differences between pairs of sequences range from 22% to 39%. These values should be compared with the differences in the sequence of mitochondrial cytochrome c between mammals and amphibians (about 18%) or between mammals and insects (about 33%). Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50015 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.

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Sulphide as an inhibitor and electron donor for the cytochrome c oxidase system

Canadian Journal of Biochemistry ◽

10.1139/o82-076 ◽

1982 ◽

Vol 60 (6) ◽

pp. 613-623 ◽

Cited By ~ 115

Author(s):

P. Nicholls ◽

J.-K. Kim

Keyword(s):

Cytochrome C ◽

Oxygen Uptake ◽

Cytochrome C Oxidase ◽

Submitochondrial Particles ◽

Inhibitory Interaction ◽

Cytochromes C ◽

Subsequent Step ◽

Oxidase Enzyme ◽

Rapid Reaction ◽

The One

Anomalies both kinetic and equilibrium in nature are described for the inhibition of cytochrome c oxidase activity by sulphide in the isolated enzyme and in submitochondrial particles. These anomalies are related to the involvement of more than 1 mol of sulphide in the blockage of one cytochrome aa3 centre. Sulphide reduces resting cytochrome a3, a reaction that results in oxygen uptake and the loss of a sulphide molecule. Sulphide can also reduce cytochromes c and a; in the former case, a part of the one-equivalent oxidation product, presumed to be the SH∙ radical, reacts with oxygen. Such oxygen uptake is also seen under aerobic conditions when ferricyanide reacts with sulphide. Three phases are identified in the inhibitory interaction of sulphide with the cytochrome c oxidase enzyme itself: an initial rapid reaction involving sulphide oxidation, oxygen uptake, and conversion of cytochrome aa3 into the low-spin "oxyferri" form; a subsequent step in which sulphide reduces cytochrome a; and the final inhibitory step in which a third molecule of sulphide binds the a3 iron centre in the cytochrome [Formula: see text] (oxy) species to give cytochrome [Formula: see text]. The initial events parallel some of the events in the interaction of the cytochrome c – cytochrome aa3 system with monothiols; the final inhibitory event resembles that with cyanide.

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Multiple light-induced reactions of cytochromes b and c in Rhodopseudomonas spheroides

Biochemical Journal ◽

10.1042/bj1140793 ◽

1969 ◽

Vol 114 (4) ◽

pp. 793-799 ◽

Cited By ~ 13

Author(s):

O. T. G. Jones

Keyword(s):

Cytochrome C ◽

Cytochrome B ◽

Photochemical Reaction ◽

Room Temperature ◽

Close Association ◽

Antimycin A ◽

Reaction Centre ◽

Difference Spectra ◽

Cytochromes C ◽

Rhodopseudomonas Spheroides

Illumination of chromatophore preparations from Rhodopseudomonas spheroides causes the oxidation of a cytochrome c and a slight oxidation of a cytochrome b with a maximum at 560nm. When illuminated in the presence of antimycin A the oxidation of cytochrome c was more pronounced and cytochrome b560 was reduced; the dark oxidation of cytochrome b560 was biphasic in the presence of succinate, but not in the presence of NADH, a less effective reductant. Split-beam spectroscopy showed that, in addition to the reduction of cytochrome b560, another pigment with maxima at 565 and 537nm. was reduced and was more rapidly oxidized in the dark than cytochrome b560. This pigment, tentatively identified as cytochrome b565, was also detected in spectra at 77°k, after brief illumination at room temperature; the maxima at 77°k were at 562 and 536nm. In the absence of antimycin A, light caused a transient reduction of cytochrome b565 and an oxidation of cytochrome b560. Dark oxidation of b565 was rapid, even in the presence of antimycin A and succinate. Difference spectra, at 77°k, of ascorbate-reduced minus succinate-reduced chromatophores or of anaerobic succinate-reduced minus aerobic succinate-reduced chromatophores suggested that two cytochromes c were present, with maxima at 547 and 549nm. When chromatophores frozen at 77°k were illuminated both these cytochromes c were oxidized, indicating a close association with the photochemical reaction centre. A scheme involving two reaction centres is proposed to explain these results.

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The effect of complete or specific partial acetimidylation on the biological properties of cytochrome c and cytochrome c-T

Biochemical Journal ◽

10.1042/bj2170595 ◽

1984 ◽

Vol 217 (3) ◽

pp. 595-599 ◽

Cited By ~ 11

Author(s):

C J A Wallace

Keyword(s):

Structural Change ◽

Cytochrome C ◽

Oxygen Uptake ◽

Redox Potential ◽

Biological Properties ◽

Amino Groups ◽

Cytochromes C ◽

Restricted Region ◽

Horse Cytochrome

The biological consequences of acetimidylation of all 19 epsilon-amino groups of horse cytochrome c are a slight decrease in both the redox potential of the protein and its ability to stimulate oxygen uptake in the cytochrome c-depleted-mitochondria assay. Examination of a number of specific partially acetimidylated analogues and acetimidylated cytochromes c of other species has shown that the changes in biological properties, which are associated with a slight structural change as monitored by n.m.r. spectroscopy [Boswell, Moore, Williams, Harris, Wallace, Bocieck & Welti (1983) Biochem. J. 213, 679-686], appear to stem from modification of residues in a restricted region of the sequence. The failure of the redox potential of Saccharomyces cerevisae cytochrome c to be affected by acetimidylation suggests that it is lysine-53, absent from that species, that is the sensitive residue.

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Physicochemical properties of two atypical cytochromes c, Crithidia cytochrome c-557 and Euglena cytochrome c-558

Biochemical Journal ◽

10.1042/bj1490155 ◽

1975 ◽

Vol 149 (1) ◽

pp. 155-167 ◽

Cited By ~ 30

Author(s):

G W Pettigrew ◽

I Aviram ◽

A Schejter

Keyword(s):

Cytochrome C ◽

Physicochemical Properties ◽

High Spin ◽

Visible Spectrum ◽

Prosthetic Group ◽

Ph Values ◽

Cytochromes C ◽

Kinetics Of ◽

Alkaline Isomerization ◽

Mitochondrial Cytochromes

Cytochrome c-557 from Crithidia oncopelti and cytochrome c-558 from Euglena gracilis are mitochondrial cytochromes c that have an atypical haem-binding site. It was of interest to know whether the loss of one thioether bond affected the physicochemical properties of these cytochromes. The thermodynamic parameters of the redox potential were measured. The reaction with imidazole, the kinetics and thermodynamics of the alkaline isomerization and the effect of heating on the visible spectrum are described for the ferricytochromes. The kinetics of the loss of cyanide, the spectral changes occurring on reduction with dithionite at alkaline pH values and the reactivity with CO are described for the ferrocytochromes. In many respects the cytochromes of the two protozoans are very similar to the cytochromes of horse and yeast. The ferricytochromes do, however, undergo a reversible transition to high-spin species on heating, which may be due to the more flexible attachment of the prosthetic group. Similarly the alkaline isomers of cytochromes c-557 and c-558 give rise to high-spin proteins above pH 11. The alkaline isomerization of cytochrome c-558, involves a pKobs. of 10 and kinetics which do not obey the model of Davis et al. [(1974) J. Biol. Chem.249, 2624-2632] for horse cytochrome c. It is proposed that a model involving two ionizations, followed by a conformation change, may fit the data. Both cytochromes c-557 and c-558 combine slowly with CO at neutral pH values.

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S-Class Cytochromes c Have a Variety of Folding Patterns: Structure of Cytochrome c-553 from Desulfovibrio vulgaris Determined by the Multi-Wavelength Anomalous Dispersion Method1

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a123267 ◽

1990 ◽

Vol 108 (5) ◽

pp. 701-703 ◽

Cited By ~ 30

Author(s):

Atsushi Nakagawa ◽

Yoshiki Higuchi ◽

Noritake Yasuoka ◽

Yukiteru Katsube ◽

Tatsuhiko Yagi

Keyword(s):

Cytochrome C ◽

Anomalous Dispersion ◽

Desulfovibrio Vulgaris ◽

Cytochromes C ◽

Multi Wavelength

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The interaction between methanol dehydrogenase and the autoreducible cytochromes c of the facultative methylotroph Pseudomonas AM1

Biochemical Journal ◽

10.1042/bj1900481 ◽

1980 ◽

Vol 190 (2) ◽

pp. 481-484 ◽

Cited By ~ 18

Author(s):

D T O'Keeffe ◽

C Anthony

Keyword(s):

Cytochrome C ◽

Methanol Dehydrogenase ◽

High Ph ◽

First Order ◽

Facultative Methylotroph ◽

Cytochromes C ◽

Pure Methanol

Cytochromes cH and cL were autoreduced at high pH (pK greater than 10) and the autoreduced cytochromes reacted with CO. The autoreduction was first-order with respect to oxidized cytochrome c and was reversible by lowering the pH. Pure methanol dehydrogenase reduced cytochrome c (in the absence of methanol) by lowering the pK for autoreduction to less than 8.5. A mechanism is proposed for the autoreduction of cytochrome c and its involvement in the reaction with methanol dehydrogenase.

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Some reactions of carbon monoxide and oxygen with carbodi-imide-modified cytochrome c

Biochemical Journal ◽

10.1042/bj2760121 ◽

1991 ◽

Vol 276 (1) ◽

pp. 121-124

Author(s):

A J Mathews ◽

T Brittain

Keyword(s):

Cytochrome C ◽

Flash Photolysis ◽

Intermediate Phase ◽

Cross Linking ◽

Intramolecular Electron Transfer ◽

Electron Transfer Process ◽

Absorbance Change ◽

Cytochromes C ◽

Ph Dependent ◽

Slow Kinetic

The reactivity of carbodi-imide-modified tuna and horse heart cytochromes c with the ferrous ion ligands CO and O2 has been studied. Both modified cytochromes bind one molecule of CO. Stopped-flow and flash-photolysis experiments indicate the presence of three kinetic processes in the reaction of the cytochromes with CO. The second-order rate constants associated with all three kinetic process are pH-independent being 2.8 x 10(5) M-1.s-1, 3.8 x 10(4) M-1.s-1 and 4 x 10(3) M-1.s-1 under all conditions studied. The concentration-dependence of the contributions made by each of the processes to the overall absorbance change indicates that the fast and slow kinetic phases are associated with two forms of the cytochromes which are in equilibrium, whereas the intermediate phase arises from a separate cytochrome species. The quantum yield for the photodissociation of CO from the ferrous cytochromes is unusually low. Both modified cytochromes are capable of binding and reducing O2. In the presence of excess reductant, the modified cytochromes can catalytically reduce large molar excesses of O2. In the absence of excess reducing agent, the oxy complex initially formed undergoes a pH-dependent intramolecular electron-transfer process with half-life approx. 10 min. EDC [1-ethyl-3-(3-dimethylaminopropyl)carbodi-imide]-promoted internal cross-linking is proposed to account for differences between the EDC-modified proteins and carboxymethylated cytochrome c.

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Effects of mutating Asn-52 to isoleucine on the haem-linked properties of cytochrome c

Biochemical Journal ◽

10.1042/bj3020095 ◽

1994 ◽

Vol 302 (1) ◽

pp. 95-101 ◽

Cited By ~ 11

Author(s):

A Schejter ◽

T I Koshy ◽

T L Luntz ◽

R Sanishvili ◽

I Vig ◽

...

Keyword(s):

Cytochrome C ◽

Site Directed Mutagenesis ◽

Wild Type ◽

General Increase ◽

Reduction Potentials ◽

Cytochromes C ◽

In The Wild ◽

Order Of Magnitude ◽

The Stability ◽

Haem Iron

Asn-52 of rat cytochrome c and baker's yeast iso-1-cytochrome c was changed to isoleucine by site-directed mutagenesis and the mutated proteins expressed in and purified from cultures of transformed yeast. This mutation affected the affinity of the haem iron for the Met-80 sulphur in the ferric state and the reduction potential of the molecule. The yeast protein, in which the sulphur-iron bond is distinctly weaker than in vertebrate cytochromes c, became very similar to the latter: the pKa of the alkaline ionization rose from 8.3 to 9.4 and that of the acidic ionization decreased from 3.4 to 2.8. The rates of binding and dissociation of cyanide became markedly lower, and the affinity was lowered by half an order of magnitude. In the ferrous state the dissociation of cyanide from the variant yeast cytochrome c was three times slower than in the wild-type. The same mutation had analogous but less pronounced effects on rat cytochrome c: it did not alter the alkaline ionization pKa nor its affinity for cyanide, but it lowered its acidic ionization pKa from 2.8 to 2.2. These results indicate that the mutation of Asn-52 to isoleucine increases the stability of the cytochrome c closed-haem crevice as observed earlier for the mutation of Tyr-67 to phenylalanine [Luntz, Schejter, Garber and Margoliash (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 3524-3528], because of either its effects on the hydrogen-bonding of an interior water molecule or a general increase in the hydrophobicity of the protein in the domain occupied by the mutated residues. The reduction potentials were affected in different ways; the Eo of rat cytochrome c rose by 14 mV whereas that of the yeast iso-1 cychrome c was 30 mV lower as a result of the change of Asn-52 to isoleucine.

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