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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
2004-6-14
pubmed:abstractText
Caenorhabditis elegans clk-1 mutants cannot produce coenzyme Q(9) and instead accumulate demethoxy-Q(9) (DMQ(9)). DMQ(9) has been proposed to be responsible for the extended lifespan of clk-1 mutants, theoretically through its enhanced antioxidant properties and its decreased function in respiratory chain electron transport. In the present study, we assess the functional roles of DMQ(6) in the yeast Saccharomyces cerevisiae. Three mutations designed to mirror the clk-1 mutations of C. elegans were introduced into COQ7, the yeast homologue of clk-1: E233K, predicted to disrupt the di-iron carboxylate site considered essential for hydroxylase activity; L237Stop, a deletion of 36 amino acid residues from the carboxyl terminus; and P175Stop, a deletion of the carboxyl-terminal half of Coq7p. Growth on glycerol, quinone content, respiratory function, and response to oxidative stress were analyzed in each of the coq7 mutant strains. Yeast strains lacking Q(6) and producing solely DMQ were respiratory deficient and unable to support (6)either NADH-cytochrome c reductase or succinate-cytochrome c reductase activities. DMQ(6) failed to protect cells against oxidative stress generated by H(2)O(2) or linolenic acid. Thus, in the yeast model system, DMQ does not support respiratory activity and fails to act as an effective antioxidant. These results suggest that the life span extension observed in the C. elegans clk-1 mutants cannot be attributed to the presence of DMQ per se.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
25995-6004
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15078893-Alleles, pubmed-meshheading:15078893-Antioxidants, pubmed-meshheading:15078893-Benzoquinones, pubmed-meshheading:15078893-Binding Sites, pubmed-meshheading:15078893-Blotting, Western, pubmed-meshheading:15078893-Chromatography, High Pressure Liquid, pubmed-meshheading:15078893-Electron Transport, pubmed-meshheading:15078893-Flow Cytometry, pubmed-meshheading:15078893-Glycerol, pubmed-meshheading:15078893-Hydrogen Peroxide, pubmed-meshheading:15078893-Mass Spectrometry, pubmed-meshheading:15078893-Mitochondria, pubmed-meshheading:15078893-Models, Chemical, pubmed-meshheading:15078893-Mutation, pubmed-meshheading:15078893-NADH Dehydrogenase, pubmed-meshheading:15078893-Oxidative Stress, pubmed-meshheading:15078893-Oxygen Consumption, pubmed-meshheading:15078893-Peptides, pubmed-meshheading:15078893-Plasmids, pubmed-meshheading:15078893-Saccharomyces cerevisiae, pubmed-meshheading:15078893-Superoxides, pubmed-meshheading:15078893-Time Factors, pubmed-meshheading:15078893-Ubiquinone, pubmed-meshheading:15078893-alpha-Linolenic Acid
pubmed:year
2004
pubmed:articleTitle
Demethoxy-Q, an intermediate of coenzyme Q biosynthesis, fails to support respiration in Saccharomyces cerevisiae and lacks antioxidant activity.
pubmed:affiliation
Centro Andaluz de Biologia del Desarrollo, Universidad Pablo de Olavide, 41013-Sevilla, Spain.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't