Metabolic changes underlying the higher accumulation of glutathione in Saccharomyces cerevisiae mutants
- 365 Downloads
Molecular mechanisms leading to glutathione (GSH) over-accumulation in a Saccharomyces cerevisiae strain produced by UV irradiation-induced random mutagenesis were studied. The mutant accumulated GSH but also cysteine and γ-glutamylcysteine in concentrations that were several fold higher than in its wild-type parent strain under all studied cultivation conditions (chemostat, fed-batch, and turbidostat). Transcript analyses along with shotgun proteome quantification indicated a difference in the expression of a number of genes and proteins, the most pronounced of which were several fold higher expression of CYS3, but also that of GSH1 and its transcriptional activator YAP1. This together with the higher intracellular cysteine concentration is most likely the primary factor underlying GSH over-accumulation in the mutant. Comparative sequencing of GSH1 and the fed-batch experiments with continuous cysteine addition demonstrated that the feedback inhibition of Gsh1p by GSH was still operational in the mutant.
KeywordsSaccharomyces cerevisiae Glutathione Cysteine GSH1 CYS3 YAP1
The financial support for this research was provided by the Enterprise Estonia project EU22704, Estonian Ministry of Education and Research grant SF0140090s08, and by Estonian Science Foundation grant G7323. We would like to thank Dr. Chris Powell for critical revision of the manuscript.
- Grant CM, MacIver FH, Dawes IW (1997) Glutathione synthetase is dispensable for growth under both normal and oxidative stress conditions in the yeast Saccharomyces cerevisiae due to an accumulation of the dipeptide γ-glutamylcysteine. Mol Biol Cell 8:1699–1707Google Scholar
- Hamada S, Tanaka H, Sakato K (1986) Process for producing glutathione. US Patent 4(582):801Google Scholar
- Ikeno Y, Tanno K, Omori I, Yamada R (1977) Glutathione. JP patent 52(087):296Google Scholar
- Kono G, Harada M, Sugisaki K, Nishida M (1977) High glutathione-containing yeast. JP Patent 52(125):687Google Scholar
- Lai J, Lee S, Hsieh C, Hwang C, Liao C (2008) Saccharomyces cerevisiae strains for hyper-producing glutathione and γ-glutamylcysteine and process of use. US Patent 7(371):557Google Scholar
- Thomas D, Surdin-Kerjan Y (1997) Metabolism of sulfur amino acids in Saccharomyces cerevisiae. Microbiol Mol Biol R 61:503–532Google Scholar