Redox Regulation of Cytochrome C Oxidase Assembly

Shy1 couples Cox1 translational regulation to cytochrome c oxidase assembly.

Cytochrome c oxidase (complex IV) of the respiratory chain is assembled from nuclear and mitochondrially-encoded subunits. Defects in the assembly process lead to severe human disorders such as Leigh syndrome. Shy1 is an assembly factor for complex IV in Saccharomyces cerevisiae and mutations of its human homolog, SURF1, are the most frequent cause for Leigh syndrome. We report that Shy1 promot...

Mitochondrial regulation of caspase activation by cytochrome oxidase and tetramethylphenylenediamine via cytosolic cytochrome c redox state.

Cytochrome c release from mitochondria induces caspase activation in cytosols; however, it is unclear whether the redox state of cytosolic cytochrome c can regulate caspase activation. By using cytosol isolated from mammalian cells, we find that oxidation of cytochrome c by added cytochrome oxidase stimulates caspase activation, whereas reduction of cytochrome c by added tetramethylphenylenedia...

Assembly of cytochrome c oxidase: what can we learn from patients with cytochrome c oxidase deficiency?

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 ...

Redox-linked Proton Transfer by Cytochrome c Oxidase

Redox transitions between oxygen intermediates in cytochrome-c oxidase.

Some intermediates in the reduction of O2 to water by cytochrome-c oxidase have been characterized by optical, Raman, and magnetic circular dichroism spectroscopy. The so-called "peroxy" (P) and "ferryl" (F) forms of the enzyme, which have been considered to be intermediates of the oxygen reaction, can be generated when the oxidized enzyme reacts with H2O2, or when the two-electron reduced ("CO...