Identification of 2-Cys Peroxiredoxin (BmTPx-2) as Antioxidant Active Molecule from Babesia microti

Abstract

Peroxiredoxins (Prxs) are a family of antioxidant enzymes that reduce peroxides in the presence of thioredoxin, thioredoxin reductase, and nicotinamide adenine dinucleotide phosphate (NADPH) to resist oxidative stress. In this study, we identified and isolated a 2-Cys Prx designated as ‘Prx2’ from Babesia microti, with a full-length cDNA of 826 bp and an open reading frame (ORF) of 756 bp, which encodes a 251-amino acid protein. BLAST analysis demonstrated that Prx2 shows the typical features of members of the 2-Cys Prx family, which includes harboring two conserved VCP motifs with Cys101 and Cys221 conserved cysteine residues. Recombinant Prx2 was expressed in Escherichia coli and analyzed by western blot. The antioxidant activity of Prx2 was demonstrated using a mixed-function oxidation (MFO) system and oxidation of NADPH. Furthermore, Prx2 mRNA expression level in parasites at the erythrocytes and tick stages were analyzed by real-time fluorescence quantitative PCR. Peak Prx2 mRNA transcription was detected eight days after infection at the erythrocyte stage, but not at the tick stage. Taken together, this study characterized Prx2 from B. microti as an antioxidant molecule that was specifically transcribed at the erythrocyte stage.