Kinetic comparisons of 5A and 5B isozymes of yeast cytochrome c oxidase
نویسندگان
چکیده
aerobic andmicroaerobic conditions. Our data revealed that the cbb3-type oxidase is the major terminal oxidase under aerobic conditions while both cbb3-type and bd-type oxidases are involved in respiration at low-O2 tensions. On the contrary, the low O2-affinity A-type cytochrome c oxidasewas not detected in our experimental conditions even under aerobic conditions and would therefore not be required for aerobic respiration in S oneidensisMR-1. In addition, the deduced amino acid sequence suggests that the A-type cytochrome c oxidase is a ccaa3-type oxidase since an uncommon extra-C terminal domain contains two c-type heme-binding motifs, an uncommon feature among A-type oxidases.
منابع مشابه
Comparisons of subunit 5A and 5B isoenzymes of yeast cytochrome c oxidase
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. Previous studies have reported...
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