Abstract
Coenzyme Q is a lipid molecule required for respiration and antioxidant protection. Q biosynthesis in Saccharomyces cerevisiae requires nine proteins (Coq1p-Coq9p). We demonstrate in this study that Q levels are modulated during growth by its conversion from demethoxy-Q (DMQ), a late intermediate. Similar conversion was produced when cells were subjected to oxidative stress conditions. Changes in Q(6)/DMQ(6) ratio were accompanied by changes in COQ7 gene mRNA levels encoding the protein responsible for the DMQ hydroxylation, the penultimate step in Q biosynthesis pathway. Yeast coq null mutant failed to accumulate any Q late biosynthetic intermediate. However, in coq7 mutants the addition of exogenous Q produces the DMQ synthesis. Similar effect was produced by over-expressing ABC1/COQ8. These results support the existence of a biosynthetic complex that allows the DMQ(6) accumulation and suggest that Coq7p is a control point for the Q biosynthesis regulation in yeast.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Hydroxylation
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Methyltransferases / genetics
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Methyltransferases / metabolism
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Methyltransferases / physiology
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Mitochondrial Proteins / genetics
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Mitochondrial Proteins / metabolism
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Mitochondrial Proteins / physiology
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Oxidative Stress
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RNA, Fungal / metabolism
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Saccharomyces cerevisiae Proteins / physiology
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Ubiquinone / biosynthesis*
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Ubiquinone / chemistry
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Ubiquinone / genetics
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Ubiquinone / metabolism
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Ubiquinone / physiology
Substances
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COQ4 protein, S cerevisiae
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COQ8 protein, S cerevisiae
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Mitochondrial Proteins
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RNA, Fungal
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Saccharomyces cerevisiae Proteins
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ubiquinone 6
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Ubiquinone
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COQ5 protein, S cerevisiae
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Methyltransferases
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3,4-dihydroxy-5-hexaprenylbenzoate methyltransferase
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ubiquinone 7