Peroxiredoxins (Prx) have received considerable attention during recent years. This study demonstrates that two typicalPseudomonas-derived 2-Cys Prx proteins, PpPrx and PaPrx can alternatively function as a peroxidase and chaperone. The amino acid sequences of these two Prx proteins exhibit 93% homology, but PpPrx possesses an additional cysteine residue, Cys112, instead of the alanine found in PaPrx. PpPrx predominates with a high molecular weight (HMW) complex and chaperone activity, whereas PaPrx has mainly low molecular weight (LMW) structures and peroxidase activity. Mass spectrometry and structural analyses showed the involvement of Cys112 in the formation of an inter-disulfide bond, the instability of LMW structures, the formation of HMW complexes, and increased hydrophobicity leading to functional switching of Prx proteins between peroxidase and chaperone.
An, Byung Chull, Seung Sik Lee, Hyun Suk Jung, Jin Young Kim, Yuno Lee, Keun Woo Lee, Sang Yeol Lee, Bhumi Nath Tripathi, Byung Yeoup Chung