Significant enhancement of hPrx1 chaperone activity through lysine acetylation

The reversible acetylation of proteins plays a key role in regulating biological processes, including chromatin remodeling, progression of the cell cycle, and actin nucleation. Human peroxiredoxin 1(hPrx1), one of the most abundant proteins in the cytoplasm, has been shown to be acetylated in human liver-carcinoma tissues. However, little is known about what function(s) the acetylation serves for hPrx1. Herein, using the method of genetic code expansion, we incorporated N^ε-acetyllysine (AcK) site-specifically into hPrx1. Our data showed that acetylation the K ²⁷ residue promotes oligomerization of hPrx1 at low concentrations. In addition, K²⁷-acetylated hPrx1(hPrx1-AcK27) exhibited greatly enhanced chaperone activity (e.g. protecting the protein malate dehydrogenase (MDH) from thermally induced aggregation and assisting the refolding of denatured citrate synthase (CS)). These findings suggest that the site-specific acetylation of hPrx1 may change its biological role in response to environmental changes. Time for a substitution: The non-canonical amino acid N ^ε-acetyllysine was incorporated into human peroxiredoxin 1 (hPrx1) through amber codon suppression to study the function of lysine acetylation in modulating the chaperone activity of hPrx1. This site-specific acetylation was found to affect both hPrx1 oligomerization and its protein-refolding activity.