Antioxidant activity of the main component of the outermost layer of the yeast spore wall, bisformyl dityrosine

Abstract

The spore wall of the budding yeast Saccharomyces cerevisiae has a multilaminar structure and its outermost layer, termed the dityrosine layer, is mainly composed of a phenolic compound, N,N’-bisformyl dityrosine. The dityrosine layer is a structure unique to the spore wall and it is not formed in the vegetative cell wall. We found that spores are resistant to free radicals compared to vegetative cells. dit1Δ spores, which lack the dityrosine layer, were sensitive to free radicals, indicating that the dityrosine layer confers to make spores resistant to oxidative stresses. Furthermore, by ectopically expression of DIT1, DIT2 and DTR1; N,N’-bisformyl dityrosine were produced conveniently and was found secreted in the media. Oxidative stress assay using DPPH and ABTS showed that N,N’-bisformyl dityrosine can scavenge free radicals. Our results suggest that the dityrosine layer protect spores from oxidative stresses. N,N’-bisformyl dityrosine may be an intriguing material as an antioxidant.