Improvement of chaperone activity of 2-Cys peroxiredoxin using gamma ray.

A typical 2-cysteine peroxiredoxin (2-Cys Prx) PaPrx can act alternatively as thioredoxin (Trx)-dependent peroxidase and molecular chaperone in Pseudomonas aeruginosa PAO1. In addition, the functional switch of PaPrx is regulated by its structural change which is dependently induced by stress conditions. In the present study, we examined the effect of gamma ray on structural modification related to chaperone activity of PaPrx. The structural change of PaPrx occupied with gamma ray irradiation (2 kGy) based on polyacrylamide gel electrophoresis (PAGE) analysis and the functional change also began. The enhanced chaperone activity was increased about 3-4 folds at 30 kGy gamma irradiation compared with nonirradiated PaPrx, while the peroxidase activity was significantly decreased. We also investigated the influence of the gamma ray on protein hydrophobicity as related to chaperone function. The exposure of hydrophobic domains reached a peak at 30 kGy gamma ray and then decreased dependently with increasing gamma irradiation. Our results suggest that highly enhanced chaperone activity could be adapted for use in bio-engineering systems and industrial applications such as enzyme stabilization during industrial process (inactivation protection), improvement of useful protein productivity (refolding and secretion) and industrial animal cell cultivation (stress protection).