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Báo cáo khoa học: Roles of 1-Cys peroxiredoxin in haem detoxification in the human malaria parasite Plasmodium falciparum

In the present study, we investigated whetherPlasmodium falciparum1-Cys peroxiredoxin (Prx) (Pf1-Cys-Prx), a cytosolic protein expressed at high lev-els during the haem-digesting stage, can act as an antioxidant to cope with the oxidative burden of haem (ferriprotoporphyrin IX; FP). Recombinant Pf1-Cys-Prx protein (rPf1-Cys-Prx) competed with glutathione (GSH) for FP and inhibited FP degradation by GSH. When rPf1-Cys-Prx was added to GSH-mediated FP degradation, the amount of iron released was reduced to 23% of the reaction without the protein (P. | iFEBS Journal Roles of 1-Cys peroxiredoxin in haem detoxification in the human malaria parasite Plasmodium falciparum Shin-ichiro Kawazu1 2 Nozomu Ikenoue1 Hitoshi Takemae1 2 Kanako Komaki-Yasuda1 2 and Shigeyuki Kano1 1 Research Institute InternationalMedicalCenter of Japan Tokyo Japan 2 Precursory Research for Embryonic Science and Technology Japan Science and Technology Agency Saitama Japan Keywords glutathione haem malaria peroxiredoxin Plasmodium falciparum Correspondence S.-i. Kawazu Research Institute International Medical Center of Japan 1-21-1 Toyama Shinjuku-ku Tokyo 162-8655 Japan Fax 81 3 3202 7364 Tel 81 3 3202 7181 extn 2878 E-mail skawazu@ri.imcj.go.jp Received 30 December 2004 revised 9 February 2005 accepted 14 February 2005 doi 10.1111 j.1742-4658.2005.04611.x In the present study we investigated whether Plasmodium falciparum 1-Cys peroxiredoxin Prx Pfl-Cys-Prx a cytosolic protein expressed at high levels during the haem-digesting stage can act as an antioxidant to cope with the oxidative burden of haem ferriprotoporphyrin IX FP . Recombinant Pf1-Cys-Prx protein rPf1-Cys-Prx competed with glutathione GSH for FP and inhibited FP degradation by GSH. When rPf1-Cys-Prx was added to GSH-mediated FP degradation the amount of iron released was reduced to 23 of the reaction without the protein P 0.01 . The rPfl-Cys-Prx bound to FP-agarose at pH 7.4 which is the pH of the parasite cytosol. The rPf1-Cys-Prx could completely protect glutamine synthetase from inactivation by the dithiothreitol-Fe3 -dependent mixed-function oxidation system and it also protected enolase from inactivation by coincubation with FP GSH. Incubation of white ghosts of human red blood cells and FP with rPf1-Cys-Prx reduced formation of membrane associations with FP to 75 of the incubation without the protein P 0.01 . The findings of the present study suggest that Pf1-Cys-Prx protects the parasite against oxidative stresses by binding to FP slowing the rate of GSH-medi-ated FP .