Abstract:
Peroxiredoxins (Prdx) are thiol specific antioxidant enzymes that play a pivotal role in cellular oxidative
stress by reducing toxic peroxide compounds into nontoxic products. In this study, we identified and
characterized a peroxiredoxin 6 counterpart from Japanese eel (Anguilla japonica) (AjPrdx6) at molecular,
transcriptional and protein level. The identified full-length coding sequence of AjPrdx6 (669 bp) coded for
a polypeptide of 223 aa residues (24.9 kDa). Deduced protein of AjPrdx6 showed analogy to characteristic
structural features of 1-cysteine peroxiredoxin sub-family. According to the topology of the generated
phylogenetic reconstruction AjPrdx6 showed closest evolutionary relationship with Salmo salar. As
detected by Quantitative real time PCR (qPCR), AjPrdx6 mRNA was constitutively expressed in all the
tissues examined. Upon the immune challenges with Edwardsiella tarda, lipopolysaccharides and polyinosinic:polycytidylic acid, expression of AjPrdx6 mRNA transcripts were significantly induced. The
general functional properties of Prdx6 were confirmed using purified recombinant AjPrdx6 protein by
deciphering its potent protective effects on cultured vero cells (kidney epithelial cell from an African
green monkey) against H2O2-induced oxidative stress and protection against oxidative DNA damage
elicited by mixed function oxidative (MFO) system. Altogether, our findings suggest that AjPrdx6 is a
potent antioxidant protein in Japanese eels and its putative immune relevancy in pathogen stress
mounted by live-bacteria or pathogen associated molecular patterns (PAMPs)
