Cloning, sequencing, and mutation of thiol-specific antioxidant gene of Saccharomyces cerevisiae.

摘要: We have previously shown that the yeast Saccharomyces cerevisiae contains an antioxidant enzyme can provide protection against a thiol-containing oxidation system but not without thiol. This 25-kDa was thus named thiol-specific (TSA). now isolated and sequenced genomic DNA fragment encodes TSA. Comparison of predicted amino acid sequence TSA with those conventional enzymes, including catalases, peroxidases, superoxide dismutases, revealed no homology. The 195-amino 2 cysteine residues. Southern blot analysis petite DNA, studies protein synthesis inhibitors, immunoblot analyses cytosolic mitochondrial proteins suggest is encoded by nuclear (chromosome XIII). gene selectively disrupted homologous recombination. haploid tsa mutant viable under air, suggesting essential for cell viability. growth rates wild-type strains were identical anaerobic conditions. However, aerobic conditions, especially in presence methyl viologen or peroxide (t-butyl hydroperoxide H2O2), rate significantly less than cells. result suggests physiologically important antioxidant.