Molecular characterization of a 2-Cys peroxiredoxin from the human malaria parasite Plasmodium falciparum

• Published in: Molecular and biochemical parasitology 2001-08, Vol.116 (1), p.73-79
• Main Authors: Kawazu, S, Komaki, K, Tsuji, N, Kawai, S, Ikenoue, N, Hatabu, T, Ishikawa, H, Matsumoto, Y, Himeno, K, Kano, S
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antioxidants; Cloning, Molecular; Molecular Sequence Data; Peroxidases - genetics; peroxiredoxin; Peroxiredoxin VI; Peroxiredoxins; PfPrx1 protein; PfPrx2 protein; Plasmodium falciparum; Plasmodium falciparum - enzymology; Plasmodium falciparum - genetics; Plasmodium falciparum - pathogenicity; Protozoan Proteins - genetics; Sequence Analysis, DNA; Sequence Homology, Amino Acid
• ISSN: 0166-6851
• DOI: 10.1016/s0166-6851(01)00308-5

We have identified the 2-Cys peroxiredoxin (PfPrx-1) from the human malaria parasite Plasmodium falciparum. The PfPrx-1 showed the highest identity at amino acid level to the type II Prx among the currently known six subfamilies of mammalian Prx. The sequence identity between the PfPrx-1 and the previously reported 1-Cys Prx of P. falciparum (PfPrx-2), which corresponded to mammalian type VI Prx, was 25%. This suggests that the parasite possesses two Prx subfamilies. The PfPrx-1 showed significant sequence similarities with those of 2-Cys peroxiredoxins of plants in the BLASTX search. This may reflect the consequences of a genetic transfer from an algal endosymbiont to the parasite nucleus during evolution. The recombinant PfPrx-1 protein (rPfPrx-1) was expressed as a histidine fusion protein in Escherichia coli and purified with Ni chromatography. The rPfPrx-1 existed as dimers under non-reducing conditions and dissociated into monomers in the presence of dithiothreitol. The PfPrx-1 protein also exists as a dimer in the parasites themselves. The reduction of the oxidized enzyme by the donation of electrons from E. coli thioredoxin (Trx)/Trx reductase system was demonstrated in its reaction with H(2)O(2), using the rPfPrx-1 protein. These results suggested that the PfPrx-1 can act as a terminal peroxidase of the parasite Trx system. An elevated expression of the PfPrx-1 protein seen in the trophozoite, the stage with active metabolism, suggests an association of the parasite Trx system with its intracellular redox control.