Yes, together we can…. A highly conserved histidine residue in 2-Cys peroxiredoxins acts as a pH sensor for oligomerization

by Luis E. S. Netto

Peroxiredoxin (Prx) enzymes are becoming more and more popular among other reasons due to their high reactivity towards hydroperoxides and to their abundance. As a consequence, Prxs are proposed as biological sensors of hydrogen peroxide. It is interesting to observe that since their beginnings (in the end of the 60’s), one feature that called attention was their ability to form high molecular weight species, visible by electron microscopy [1]. It was almost twenty years later that the thiol-dependent peroxidase activity of Prx enzymes was described.

Among Prx family of proteins, 2-Cys Prx enzymes (those belonging to the AhpC/Prx1 group) can adopt a wide array of quartenary

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Peroxide signaling through thiol switches: chemical and biological aspects.

by Luis E. S. Netto

It is now well accepted that oxidants and other redox intermediates are not only damaging compounds, but also act as signaling molecules. This is especially evident for hydrogen peroxide, whose generation and degradation are finely regulated through multiple enzymatic systems. Proteins whose activities are based on Cysteine (Cys) residues are frequently reported to be oxidized in various biological systems in conditions where hydrogen peroxide is also generated. As the most parsimonious hypothesis, these proteins are frequently assumed to be directly oxidized by hydrogen peroxide, although this is not always supported by chemical data.

For instance, Protein Tyrosine Phosphatases

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