TAILIEUCHUNG - Evidence for the presence of a second electron donor for the cytoplasmic thioredoxins in the yeast Saccharomyces cerevisiae

In yeast, the cytoplasmic thioredoxin system is composed of NADPH, thioredoxin reductase-1 (TRR1) and 2 thioredoxin genes (TRX1, TRX2). In this study, using yeast knockout mutants for TRR1, TRX1 and TRX2 genes, the role of the thioredoxin system in methionine sulfoxide reduction was investigated. | Turk J Biol 30 (2006) 133-138 © TÜB‹TAK Evidence for the Presence of a Second Electron Donor for the Cytoplasmic Thioredoxins in the Yeast Saccharomyces cerevisiae Ahmet KOÇ, Hüseyin Ç. KARAKAYA, Ercan S. ÜNLÜ Molecular Genetics Laboratory, Department of Biology, ‹zmir Institute of Technology, 35430- Urla, ‹zmir - TURKEY Received: Abstract: In yeast, the cytoplasmic thioredoxin system is composed of NADPH, thioredoxin reductase-1 (TRR1) and 2 thioredoxin genes (TRX1, TRX2). In this study, using yeast knockout mutants for TRR1, TRX1 and TRX2 genes, the role of the thioredoxin system in methionine sulfoxide reduction was investigated. Cells lacking both TRX1 and TRX2 genes simultaneously were not able to reduce methionine sulfoxides to methionine; however, mutants missing the TRR1 gene were able to reduce methionine sulfoxides to methionine, which showed that electrons could be transferred from NADPH to thioredoxins in the absence of TRR1. Similar results were observed for 3-phosphoadenosine 5-phosphosulfate reduction in the inorganic sulfate assimilation pathway. Results from both assays suggested that yeast cells have additional cytoplasmic thioredoxin reductase activity that could compensate for methionine sulfoxide reduction and sulfate assimilation in the absence of TRR1. This report also constitutes the first evidence that thioredoxins are the in vivo electron donors for methionine sulfoxide reductases in yeast. Key Words: Thioredoxin reductase, thioredoxin, methionine, methionine sulfoxide, yeast, Saccharomyces cerevisiae Maya (Saccharomyces cerevisiae) Sitoplazmik Tiyoredoksinleri için ‹kinci Bir Elektron Donörünün Varl›¤›n› Gösteren Deliller Özet: Maya mantar›nda sitoplazmik tioredoksin sistemi NADPH, bir tane tiyoredoksin redüktaz (TRR1) ve iki tane tiyoredoksin (TRX1, TRX2) den oluflmaktad›r. Bu çal›flmada, genomundan TRR1, TRX1 ve TRX2 genleri ç›kart›lm›fl maya hücrelerinin metiyonin sülfoksit indirgeme kapasiteleri incelenmifltir. ‹ki .

• Sinh học
• Thioredoxin reductase
• Methionine sulfoxide
• Saccharomyces cerevisiae
• TRX2 genes
• Thioredoxin system
• Journal of Chemistry
• Meleagris gallopavo
• Thioredoxin protein (Trx)
• Lineweaver–Burk plots
• Characterization purification
• Rainbow trout
• Metal ions
• Report medicine
• traditional medicine
• scientific reports
• immune system
• Antimicrobial
• biosynthesis
• medicine
• cell proliferation
• oxidation
• intermediate cells
• medical analysis