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Saccharomyces cerevisiae coq10 null mutants are responsive to antimycin A
Author(s) -
Busso Cleverson,
Tahara Erich B.,
Ogusucu Renata,
Augusto Ohara,
FerreiraJunior Jose Ribamar,
Tzagoloff Alexander,
Kowaltowski Alicia J.,
Barros Mario H.
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2010.07862.x
Subject(s) - coenzyme q – cytochrome c reductase , antimycin a , mutant , alternative oxidase , reductase , coenzyme q10 , saccharomyces cerevisiae , biochemistry , mitochondrial respiratory chain , cytochrome , biology , cytochrome c oxidase , respiratory chain , cofactor , mitochondrion , cytochrome c , enzyme , yeast , gene
Deletion of COQ10 in Saccharomyces cerevisiae elicits a respiratory defect characterized by the absence of cytochrome c reduction, which is correctable by the addition of exogenous diffusible coenzyme Q 2 . Unlike other coq mutants with hampered coenzyme Q 6 (Q 6 ) synthesis, coq10 mutants have near wild‐type concentrations of Q 6 . In the present study, we used Q‐cycle inhibitors of the coenzyme QH 2 –cytochrome c reductase complex to assess the electron transfer properties of coq10 cells. Our results show that coq10 mutants respond to antimycin A, indicating an active Q‐cycle in these mutants, even though they are unable to transport electrons through cytochrome c and are not responsive to myxothiazol. EPR spectroscopic analysis also suggests that wild‐type and coq10 mitochondria accumulate similar amounts of Q 6 semiquinone, despite a lower steady‐state level of coenzyme QH 2 –cytochrome c reductase complex in the coq10 cells. Confirming the reduced respiratory chain state in coq10 cells, we found that the expression of the Aspergillus fumigatus alternative oxidase in these cells leads to a decrease in antimycin‐dependent H 2 O 2 release and improves their respiratory growth.