Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 7, 2008
Publication Date: N/A
Technical Abstract: Ymr315w protein levels have been shown to increase in cells grown on xylose. The mRNA level for the YMR315W gene was also seen to increase in cells grown on xylose, indicating an important function for YMR315W during growth on xylose. YMR315W encodes for a highly conserved protein of unknown function and, based on sequence similarity to known motifs, is predicted to be a dehydrogenase. The YMR315W gene is also co-regulated under numerous stress conditions with six other oxidoreductases, including the GRE3 gene, which has been shown to function in xylose metabolism. In this study, the YMR315W gene was cloned and the protein was over expressed in Saccharomyces cerevisiae. Lysates from cells expressing elevated levels of the Ymr315w protein were analyzed for enzymatic activity using various substrates and compared to activities from cells that were deleted for the YMR315W gene. Lysate from cells with elevated levels of Ymr315w protein showed increased enzymatic activity toward multiple substrates. Other labs have shown that mRNA levels for the YMR315W gene also increase when cells are exposed to oxidative damage by chemicals such as H2O2. During exposure to oxidative damage, cells require increased amounts of NADPH to defend against reactive oxygen species. We found that cells lacking the YMR315W gene were sensitive to H2O2. This result suggests that YMR315W, through its NAD(P)**+-dependent dehydrogenase activity, may function to maintain cellular redox balance, a problem also encountered by cells grown on xylose.