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Biology

TÜBİTAK

2006

Saccharomyces cerevisiae

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Evidence For The Presence Of A Second Electron Donor For The Cytoplasmic Thioredoxins In The Yeast Saccharomyces Cerevisiae, Ahmet Koç, Hüseyi̇n Ç. Karakaya, Ercan S. Ünlü Jan 2006

Evidence For The Presence Of A Second Electron Donor For The Cytoplasmic Thioredoxins In The Yeast Saccharomyces Cerevisiae, Ahmet Koç, Hüseyi̇n Ç. Karakaya, Ercan S. Ünlü

Turkish Journal of Biology

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 …


Non-Histone Proteins And The Mediator Complex Are Essential For The Transcription Of Hxt2 And Hxt4 Genes In Saccharomyces Cerevisiae, Si̇nem Güzelvardar, Sezai̇ Türkel Jan 2006

Non-Histone Proteins And The Mediator Complex Are Essential For The Transcription Of Hxt2 And Hxt4 Genes In Saccharomyces Cerevisiae, Si̇nem Güzelvardar, Sezai̇ Türkel

Turkish Journal of Biology

Transcriptional activation of HXT2 and HXT4 genes require rapid reorganization of the chromatin structure on the promoter regions of these genes. In this study, it was found that the transcription of HXT2 and HXT4 genes decreased 4- to 7-fold in the yeast strain that does not contain the non-histone proteins 6A and 6B (Nhp6A/B). In addition, results of this research indicated that Nhp6A/B are required for the rapid derepression and activation of HXT2 and HXT4 transcription upon glucose signaling. Furthermore, it was found that Med2p, which provides the connection between the transcriptional activators and the basal transcription factors, is also …