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

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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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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A new non-covalent complex of semisynthetically modified tryptic fragments of cytochrome c

Biochemical Journal ◽

10.1042/bj2390333 ◽

1986 ◽

Vol 239 (2) ◽

pp. 333-337 ◽

Cited By ~ 9

Author(s):

A E Proudfoot ◽

C J Wallace ◽

D E Harris ◽

R E Offord

Keyword(s):

Biological Activity ◽

Cytochrome C ◽

Redox Potential ◽

Peptide Bond ◽

Succinate Oxidation ◽

Covalent Complex ◽

Horse Cytochrome

We have prepared a semisynthetic analogue of fully acetimidylated horse cytochrome c, a complex in which the peptide bond between residues glycine-37 and arginine-38 is lacking. In contrast with the complex that we have previously described [Harris & Offord (1977) Biochem. J. 161, 12-25], in which the break in continuity is between residues arginine-38 and lysine-39, the new analogue has a nearly normal redox potential, and can more fully restore succinate oxidation to mitochondria depleted of cytochrome c. Studies of this and other analogues lead us to propose an explanation for the low biological activity of complex (1-38)-(39-104) and a role for the invariance of arginine-38.

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Modulation of the alkaline transition in cytochrome c and cytochrome c-T by full or specific partial acetimidylation

Biochemical Journal ◽

10.1042/bj2170601 ◽

1984 ◽

Vol 217 (3) ◽

pp. 601-604 ◽

Cited By ~ 14

Author(s):

C J A Wallace

Keyword(s):

Structural Change ◽

Cytochrome C ◽

Strong Field ◽

Alternative Hypothesis ◽

Lysine Residue ◽

Comprehensive View ◽

Alkaline Transition ◽

The Relationship ◽

Horse Cytochrome

Acetimidylated horse cytochrome c and related derivatives exhibit more or less marked changes, both upscale and downscale, in apparent pK of the alkaline transition. This transition occurs when the normal methionine-80 residue is replaced at the sixth haem co-ordination position by another strong-field ligand. Analysis of the relationship between structural change and pK shift in these derivatives supports the view that the replacement ligand is a lysine residue, probably 72 or 79, and contradicts an alternative hypothesis. The results add further detail to a comprehensive view of the mechanism of this isomerization.

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The semisynthesis of analogues of cytochrome c. Modifications of arginine residues 38 and 91

Biochemical Journal ◽

10.1042/bj2150651 ◽

1983 ◽

Vol 215 (3) ◽

pp. 651-658 ◽

Cited By ~ 10

Author(s):

C J A Wallace ◽

K Rose

Keyword(s):

Cytochrome C ◽

Chemical Properties ◽

Biological Properties ◽

Adduct Formation ◽

Eukaryotic Evolution ◽

Functional Roles ◽

Arginine Residues ◽

Biological Tests ◽

Horse Cytochrome ◽

And Chemical Properties

The arginine residues at positions 38 and 91 of horse cytochrome c are absolutely conserved throughout eukaryotic evolution. For studies of the functional roles of these residues, we have prepared, by semisynthetic techniques, analogues of cytochrome c in which one or the other of the arginine residues has been modified. The products of modification by adduct formation with pentane-2,4-dione were purified and extensively characterized. In biological tests, the arginine-91-modified cytochrome c showed little difference in behaviour from native horse cytochrome c. Modification of arginine-38, however, led to extensive changes in biological and chemical properties. We also prepared and tested adducts with cyclohexane-1,2-dione and camphorquinone-10-sulphonic acid. The same effects on biological properties were noted irrespective of the nature of the modifying group. We suggest reasons for the differences in sensitivity of the two sites.

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Increasing the redox potential of isoform 1 of yeast cytochrome c through the modification of select haem interactions

Biochemical Journal ◽

10.1042/bj3620281 ◽

2002 ◽

Vol 362 (2) ◽

pp. 281-287 ◽

Cited By ~ 10

Author(s):

C. Marc LETT ◽

J. Guy GUILLEMETTE

Keyword(s):

Cytochrome C ◽

Redox Potential ◽

Point Mutations ◽

Cd Spectroscopy ◽

Wild Type ◽

Mutant Proteins ◽

Oxidation Reduction ◽

Oxidation Reduction Potential ◽

Biophysical Studies ◽

Cytochromes C

The oxidation—reduction potential of eukaryotic cytochromes c varies very little from species to species. We have introduced point mutations into isoform 1 of yeast cytochrome c (iso-1-cytochrome c) to selectively engineer a protein with a higher redox potential. Of the ten different mutant proteins generated for the present investigation Y67R, Y67K and W59H were found to be non-functional. Three other mutant proteins, L32M, L32T and T49K, were functional, but too unstable for biophysical studies. Mutant cytochromes c K79S, K79T, Y48H and Y48K were purified and characterized. The Y48K mutant is the only one that exhibits a significant increase of +117mV in redox potential compared with the wild-type protein while still supporting oxidative phosphorylation invivo. Low temperature difference spectroscopy confirmed the formation of the holoprotein, while adsorption and CD spectroscopy reveal perturbations in the structure of Y48K iso-1-cytochrome c.

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The conformation of eukaryotic cytochrome c around residues 39, 57, 59 and 74

Biochemical Journal ◽

10.1042/bj2130687 ◽

1983 ◽

Vol 213 (3) ◽

pp. 687-700 ◽

Cited By ~ 32

Author(s):

M N Robinson ◽

A P Boswell ◽

Z X Huang ◽

C G S Eley ◽

G R Moore

Keyword(s):

Cytochrome C ◽

Redox State ◽

Conformational Flexibility ◽

Candida Krusei ◽

Crystallographic Structure ◽

Conformational Heterogeneity ◽

X Ray ◽

Cytochromes C ◽

Similar Cluster ◽

Horse Cytochrome

1H-n.m.r. studies of horse, tuna, Candida krusei and Saccharomyces cerevisiae cytochromes c showed that each of the proteins contains a similar cluster of residues at the bottom of the protein that assists in shielding the haem from the solvent. The relative positions of the residues forming these clusters vary continuously with temperature, and they change with the change in protein redox state. This conformational heterogeneity is discussed with reference to the conformational flexibility of cytochrome c around residues 57, 59 and 74. Spectroscopic measurements of pKa values for Lys-55 (horse and tuna cytochromes c) and His-33 and His-39 (C. krusei and S. cerevisiae cytochromes c) are in excellent agreement with expectations based on chemical-modification studies of horse cytochrome c. [Bosshard & Zürrer (1980) J. Biol. Chem. 255, 6694-6699] and on the X-ray-crystallographic structure of tuna cytochrome c [Takano & Dickerson (1981) J. Mol. Biol. 153, 79-94, 95-115].

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A cytochrome c methyltransferase from Crithidia oncopelti.

Biochemical Journal ◽

10.1042/bj2010329 ◽

1982 ◽

Vol 201 (2) ◽

pp. 329-338 ◽

Cited By ~ 11

Author(s):

J Valentine ◽

G W Pettigrew

Keyword(s):

Cytochrome C ◽

Cell Extract ◽

Lysine Methylation ◽

Methyltransferase Activity ◽

Proline Residue ◽

Cytochromes C ◽

Lysine Residues ◽

Low Degrees ◽

Horse Cytochrome

The mitochondrial cytochrome c-557 of Crithidia oncopelti contains two lysine residues and an N-terminal proline residue that are methylated in vivo by the methyl group of methionine. The purified cytochrome can act as a methyl acceptor for a methyltransferase activity in the cell extract that uses S-adenosylmethionine as methyl donor. Crithidia cytochrome c-557 is by far the best substrate for this methyltransferase of those tested, in spite of the fact that methylation sites are already almost fully occupied. The radioactive uptake of [14C]methyl groups from S-adenosylmethionine occurred only at a lysine residue (-8) and the N-terminal proline residue. This methyltransferase appears to differ from that of Neurospora and yeast [Durban, Nochumson, Kim, Paik & Chan (1978) J. Biol. Chem. 253, 1427-1435; DiMaria, Polastro, DeLange, Kim & Paik (1979) J. Biol. Chem. 254, 4645-4652] in that lysine-72 of horse cytochrome c is a poor acceptor. Also, the Crithidia methyltransferase appears to be stable to carry lysine methylation much further to completion than do the enzymes from yeast and Neurospora, which produce very low degrees of methylation in native cytochromes c.

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