Nitro-Oleic Acid-Mediated Nitroalkylation Modulates the Antioxidant Function of Cytosolic Peroxiredoxin Tsa1 during Heat Stress in Saccharomyces cerevisiae
Fecha
2022-05-14
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MDPI
Resumen
Heat stress is one of the abiotic stresses that leads to oxidative stress. To protect themselves,
yeast cells activate the antioxidant response, in which cytosolic peroxiredoxin Tsa1 plays an important
role in hydrogen peroxide removal. Concomitantly, the activation of the heat shock response (HSR)
is also triggered. Nitro-fatty acids are signaling molecules generated by the interaction of reactive
nitrogen species with unsaturated fatty acids. These molecules have been detected in animals and
plants. They exert their signaling function mainly through a post-translational modification called
nitroalkylation. In addition, these molecules are closely related to the induction of the HSR. In this
work, the endogenous presence of nitro-oleic acid (NO2-OA) in Saccharomyces cerevisiae is identified
for the first time by LC-MS/MS. Both hydrogen peroxide levels and Tsa1 activity increased after heat
stress with no change in protein content. The nitroalkylation of recombinant Tsa1 with NO2-OA was
also observed. It is important to point out that cysteine 47 (peroxidatic) and cysteine 171 (resolving)
are the main residues responsible for protein activity. Moreover, the in vivo nitroalkylation of Tsa1
peroxidatic cysteine disappeared during heat stress as the hydrogen peroxide generated in this
situation caused the rupture of the NO2-OA binding to the protein and, thus, restored Tsa1 activity.
Finally, the amino acid targets susceptible to nitroalkylation and the modulatory effect of this PTM
on the enzymatic activity of Tsa1 are also shown in vitro and in vivo. This mechanism of response
was faster than that involving the induction of genes and the synthesis of new proteins and could be
considered as a key element in the fine-tuning regulation of defence mechanisms against oxidative
stress in yeast.
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Palabras clave
Peroxiredoxin, Tsa1, nitro-oleic acid, nitroalkylation, heat stress, nitro-fatty acids, Saccharomyces cerevisiae
Citación
Antioxidants 2022, 11, 972.