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R Bisson

Publications and source records attributed to R Bisson.

At least 19 recordsLinked to original sources
PubMed1991

The most conserved nuclear-encoded polypeptide of cytochrome c oxidase is the putative zinc-binding subunit: primary structure of subunit V from the slime mold Dictyostelium discoideum.

A full-length 515 base pairs cDNA for cytochrome c oxidase subunit V of D. discoideum was isolated from a lambda gt11 expression library. The encoded polypeptide, whose identity was confirmed by partial protein sequencing, is 119 amino acids long (Mr = 13,352) and does not contain a cleavable presequence. The protein, which is homologous to human subunit Vb and yeast subunit IV, exhibits the highest degree of sequence conservation found among nuclear-encoded subunits of cytochrome c oxidase from distantly related organisms. All the invariant residues are clustered in two regions of the C-terminus which include the putative amino acids involved in the coordination of the Zn ion tightly associated to eukaryotic oxidase.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of a cDNA coding for the mitochondrial precursor protein of cytochrome c oxidase subunit IV from the slime mold Dictyostelium discoideum.

Subunit-specific polyclonal antibodies were used to isolate cDNA clones encoding subunit IV of Dictyostelium discoideum cytochrome c oxidase. DNA sequence analysis reveals an open reading frame of 149 amino acids. As shown by sequencing of the protein N-terminus, the subunit is synthesized with a 24 residue cleavable presequence which leads to a mature polypeptide of 14305 Da. The slime mold subunit exhibits a low but significant degree of similarity with subunit Va of human and subunit VI of yeast cytochrome c oxidase.

Amino Acid Sequence↗
PubMed1991

Characterization of a cDNA encoding subunit VI of cytochrome c oxidase from the slime mold Dictyostelium discoideum.

The primary structure of subunit VI of cytochrome c oxidase from the slime mold Dictyostelium discoideum has been determined by sequencing cDNA and N-terminus of the protein. The 92 amino acid residues long polypeptide (Mr = 10,535) shows homology with subunit IV of mammalian and subunit V of yeast cytochrome c oxidase. Though smaller and synthesized without a cleavable presequence, the slime mold oxidase subunit maintains the presence of a putative membrane spanning region.

Amino Acid Sequence↗
PubMed1991

Biological markers of oxidative stress in mitochondrial myopathies with progressive external ophthalmoplegia.

According to experimental models suggesting that overproduction of oxygen free-radicals may occur when the electron transport in the respiratory chain is impaired, we searched for in vivo biological markers of oxidative stress in 11 patients affected by histologically proven mitochondrial myopathy with progressive external ophthalmoplegia (PEO) and partial cytochrome c oxidase deficiency in muscle fibres. Six of the patients carried large-scale deletions of mitochondrial DNA. Biochemical assays included the determination of plasma and erythrocyte reduced glutathione (GSH) concentration, plasma malondialdehyde, fluorescent adducts of aldehydes with plasma proteins, and serum level of lipid peroxides. In patients with PEO the mean values of lipid peroxides and of the fluorescent adducts of aldehydes with plasma proteins were significantly higher with respect to normal controls, while the mean values of plasma and erythrocyte GSH concentration were significantly lower. The reported data indicate an increase of lipid peroxidation indexes along with the reduction of one of the most important antioxidant systems and suggest the hypothesis that overproduction of reduced oxygen species might be an adjunctive cause of cell damage in mitochondrial myopathies and encephalomyopathies associated with defects of oxidative phosphorylation.

Adult↗
PubMed1989

Oxygen influences the subunit structure of cytochrome c oxidase in the slime mold Dictyostelium discoideum.

The conditions that promote the alternative expression of two nuclear-encoded subunits of cytochrome c oxidase in the slime mold Dictyostelium discoideum (Bisson, R., and Schiavo, G. (1986) J. Biol. Chem. 261, 4373-4376) have been investigated. Oxygen concentration seems to be the only factor able to cause the subunit switching. This result indicates that the polypeptide composition of the mitochondrial enzyme can be influenced by environmental conditions. The significance of this change is discussed.

Dictyostelium↗
PubMed1987

ATP induces conformational changes in mitochondrial cytochrome c oxidase. Effect on the cytochrome c binding site.

ATP influences the kinetics of electron transfer from cytochrome c to mitochondrial oxidase both in the membrane-embedded and detergent-solubilized forms of the enzyme. The most relevant effect is on the so-called "high affinity" binding site for cytochrome c which can be converted to "low affinity" by millimolar concentrations of ATP (Ferguson-Miller, S., Brautigan, D. L., and Margoliash, E. (1976) J. Biol. Chem. 251, 1104-1115). This phenomenon is characterized at the molecular level by the following features. ATP triggers a conformational change on the water-exposed surface of cytochrome c oxidase; in this process, carboxyl groups forming the cluster of negative charges responsible for binding cytochrome c change their accessibility to water-soluble protein modifier reagents; as a consequence the electrostatic field that controls the enzyme-substrate interaction is altered and cytochrome c appears to bind differently to oxidase; photolabeling experiments with the enzyme from bovine heart and other eukaryotic sources show that ATP cross-links specifically to the cytoplasmic subunits IV and VIII. Taken together, these data indicate that ATP can, at physiological concentration, bind to cytochrome c oxidase and induce an allosteric conformational change, thus affecting the interaction of the enzyme with cytochrome c. These findings raise the possibility that the oxidase activity may be influenced by the cell environment via cytoplasmic subunit-mediated interactions.

Adenosine Diphosphate↗
PubMed1987

Isolation and characterization of cytochrome c oxidase from bird and fish heart mitochondria.

1. Several bird and fish heart mitochondrial cytochrome c oxidases have been isolated with a rapid and simple method involving hydrophobic and affinity chromatography. 2. Their spectrophotometric and kinetic properties are very similar to those of the mammalian enzymes. 3. These oxidases show a polypeptide composition simpler than the mammalian enzymes being composed of 9-10, instead of 13, different polypeptides. 4. These data suggest that the complexity of the mitochondrial heart oxidase increases with the stage of evolution.

Animals↗
PubMed1986

Two different forms of cytochrome c oxidase can be purified from the slime mold Dictyostelium discoideum.

Cytochrome c oxidase was purified from mitochondria of Dictyostelium discoideum cells harvested at different phases of the vegetative stage. Comparison of the preparations by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that the smallest enzyme subunit present during exponential growth is replaced by a larger polypeptide component in the stationary phase. The two polypeptides are structurally and immunologically unrelated.

Antigen-Antibody Complex↗
PubMed1986

ATP binding to bovine heart cytochrome c oxidase. A photoaffinity labelling study.

ATP influences the kinetic properties of cytochrome c oxidase. A photoactivatable radioactive ATP analogue was used to localize the nucleotide-binding site on the bovine heart enzyme. Subunits IV and VIII were specifically labelled, suggesting that these two nuclear-coded polypeptides may play a regulatory role on the oxidase functions.

Adenosine Triphosphate↗
PubMed1979

Cytochrome c oxidase subunits in contact with phospholipids. Hydrophobic photolabeling with azidophospholipids.

The technique of photolabeling of membrane proteins with arylazidophospholipids was applied to cytochrome c oxidase. The "deep" and "shallow" labels employed reacted with all subunits of cytochrome c oxidase except V and VI: Subunits I, III, and VII were heavily labeled, Subunit II was labeled to a lesser extent, and Subunit IV was poorly labeled. Subunit I was labeled more by the deep label and Subunit VII by the shallow one. The other subunits were equally labeled by the two probes. This technique has revealed what subunits of cytochrome c oxidase interact with the lipid and their approximate position in the membrane.

Animals↗