In recent studies of mislocalized TCA cycle enzymes in S. cerevisiae, we obtained evidence for direct delivery of reducing equivalents from cytosolic NADH to the mitochondrial electron transport chain. It is also known that intact isolated yeast mitochondria can oxidize exogenous NADH. To identify and examine the responsible protein(s), a yeast open reading frame (YMR145c) was found, showing high homology to NDI1 which encodes NADH dehydrogenasa of the mitochondrial matrix. A genomic fragment containing YMR145c was amplified by PCR and the PCR product was used to create A YMR145e strains. Another open reading frame, YDL085w, which exhibits significant homology to YMR145c was identified and A YDLO85w disruption strains were created using similar PCR methods. Total NADH dehydrogenase activity in mitochondrial homogenates from cells grown on glucose is decreased 4-5 fold relative to wild type levels in in A YMR145c strains, whereas no detectable difference is observed in A YDLO85w strains. No significant difference is seen in activity levels among wild type and disruptant strains grown on glycerol plus lactate as a carbon source, which results in a 3-4 fold increase in activity relative to glucose growth. Growth phenotypes will be analyzed in detail and metabolic analyses of these strains will be presented.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology