Subunit 5 of Saccharomyces cerevisiae cytochrome c oxidase (CcO) is essential for assembly and has two isoforms, 5A and 5B. 5A is expressed under normoxic conditions, whereas 5B is expressed at very low oxygen tensions. As a consequence, COX5A-deleted strains (Δcox5A) have no or only low levels of CcO under normoxic conditions rendering them respiratory deficient.
View Article and Find Full Text PDFAssignments of IR bands of reduced minus oxidized IR difference spectra of bovine and related cytochrome c oxidases are reviewed and their linkages to specific metal centres are assessed. To aid this, redox-poised difference spectra in the presence of cyanide or carbon monoxide are presented. These ligands fix the redox states of either haem a3 alone or haem a3 and CuB respectively, while allowing redox cycling of the remaining centres.
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