Association of Deoxyhypusine Hydroxylase with Peroxiredoxin I was Modulated in the Yeast Saccharomyces cerevisiae under Oxidative Stress

다국어 초록 (Multilingual Abstract)

Eukaryotic translation initiation factor 5A (eIF5A) is the only hypusine-containing protein, which is formed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). DOHH is a novel metalloenzyme with HEAT [named for human huntingtin (H), elongation factor 3 (E), a subunit of protein phosphatase 2A (A), and the target of rapamycin (T)]-repeat motifs. Inspite of much progress in determining the roles of iron-containing DOHH holoenzyme as an eIF5A hydroxylase, little is known about iron-free apoenzyme of DOHH under certain stress conditions. For this purpose, we compared cell growth in two yeast strains subjected to oxidative damage. Thus, the existence of more viable cells in the Saccharomyces cerevisiae BY4743 (parental yeast) strain than in the DOHH- strain after $H_2O_2$ treatment indicates the importance of DOHH in protecting yeast cells against oxidative stress. To identify endogenous target proteins influenced by DOHH under oxidative damage, proteomic analysis was applied to the two yeast strains. Of these proteins, the oxidized form of peroxiredoxin I (PrxI) was concomitantly up-regulated in both strains under $H_2O_2$ treatment. Two-dimensional electrophoresis (DE) followed by immunoblot analysis shows that the recovery of the oxidized PrxI to the reduced enzyme under $H_2O_2$ treatment was found to be much slower in the DOHH- strain than in the parental strain. Based on the results, we discovered a possible interaction between DOHH and PrxI by immunoprecipitation/immunoblotting in yeast under oxidative stress. Taken together, these results suggest that DOHH might be a candidate protein for protection of yeast cells against oxidative stress in conjunction with PrxI.