c-type cytochromes are characterized by the presence of two covalent bonds linking heme to apocytochrome and by the heme attachment motif in the apoprotein. Several molecular systems for the maturation of c-type cytochromes have evolved in different organisms. The best characterized are three of them: system I, system II and system III. Heme is synthesized in bacterial cytoplasm, in plastids, a...

The lipid composition of yeast cells was manipulated by the use of an unsaturated fatty acid auxotroph of Saccharomyces cerevisiae. There was a 2-3-fold decrease in the concentration of cytochromes a+a3 when the unsaturated fatty acid content of the cells was decreased from 60-70% of the total fatty acid to 20-30%. The amounts of cytochromes b and c were also decreased under these conditions, b...

Cytochromes c are hemoproteins, with the prosthetic group covalently linked to the apoprotein, which function as electron carriers. A class of cytochromes c is defined by a CXXCH heme-binding motif where the cysteines form thioether bonds with the vinyl groups of heme. Plastids are known to contain up to three cytochromes c. The membrane-bound cytochrome f and soluble cytochrome c6 operate in p...

A combination of potentiometric analysis and electrochemically poised low-temperature difference spectroscopy was used to examine a mutant strain of Escherichia coli that was previously shown by immunological criteria to be lacking the cytochrome d terminal oxidase. It was shown that this strain is missing cytochromes d, a1, and b558 and that the cytochrome composition of the mutant is similar ...

In plastids, the conversion of energy in the form of light to ATP requires key electron shuttles, the c-type cytochromes, which are defined by the covalent attachment of heme to a CXXCH motif. Plastid c-type cytochrome biogenesis occurs in the thylakoid lumen and requires a system for transmembrane transfer of reductants. Previously, CCDA and CCS5/HCF164, found in all plastid-containing organis...

Cytochrome P-450-dependent 6 beta-hydroxylation of bile acids in rat liver contributes to the synthesis of the quantitatively important pool of 6-hydroxylated bile acids, as well as to the detoxification of hydrophobic bile acids. The lithocholic acid 6 beta-hydroxylation reaction was investigated and compared with androstenedione 6 beta-hydroxylation. Differential responses of these two activi...

The ability of Neisseria meningitidis to utilize both oxygen and nitrogen oxides as respiratory substrates allows it to thrive in the diverse environment of the human host. Genome analysis highlighted genes encoding a cbb(3) cytochrome oxidase, the aniA nitrite reductase gene and the norB nitric oxide reductase gene. In the present study, we used myxothiazol as an inhibitor of the bc(1) complex...

This article is a report on a symposium held at Experimental Biology '98 in San Francisco, California. Recent developments in site-directed mutagenesis, computer-modeling, and mechanistic analysis of cytochromes P450 and flavin-containing monooxygenases are described. A unifying theme is the elaboration of general approaches for understanding and predicting the function of individual forms of t...

We developed a Raman spectroscopy-based approach for simultaneous study of redox changes in c-and b-type cytochromes and for a semiquantitative estimation of the amount of oxygenated myoglobin in a perfused rat heart. Excitation at 532 nm was used to obtain Raman scattering of the myocardial surface of the isolated heart at normal and hypoxic conditions. Raman spectra of the heart under normal ...

Ethidium bromide intercalates between the bases of native DNA, resulting in several biological anomalies. The effects of ethidium bromide on the mitochondria of cultured mouse L cells were studied. At a concentration of 1 microg ethidium bromide/ml it was observed that concentrations of cytochromes a + a(3) and b decreased, a + a(3) more rapidly than b. In contrast, the concentration of cytochr...