Cysteine-3 and Cysteine-4 are Essential for the Thioredoxin-like Oxidoreductase and Antioxidant Activities of Plasmodium Falciparum Macrophage Migration. inhibitory factor

Alam, Athar and Goyal, Manish and Iqba, Mohd Shameel and Bindu, Samik and Dey, Sumanta and Pal, Chinmay and Maity, Pallab and Manuel , Mascarenhas Nahren and Ghoshal, Nanda and Bandyopadhyay, Uday (2011) Cysteine-3 and Cysteine-4 are Essential for the Thioredoxin-like Oxidoreductase and Antioxidant Activities of Plasmodium Falciparum Macrophage Migration. inhibitory factor. Free Radical Biology & Medicine, 50 (11). pp. 1659-1668.

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    Abstract

    Plasmodium falciparum macrophage migration inhibitory factor (PfMIF) exhibits thioredoxin (Trx)-like oxidoreductase activity but the active site for this activity and its function have not been evaluated. A bioinformatics search revealed that the conserved CXXC motif, which is responsible for Trx-like oxidoreductase activity, is absent from PfMIF. In contrast, the adjacent N-terminal Cys-3 and Cys-4 are conserved in MIF across species of malarial parasites. Mutation of either vicinal Cys-3 or Cys-4 of PfMIF abolished the Trx-like activity, whereas the mutation of the remaining Cys-59 or Cys-103 did not affect it. PfMIF has an antioxidant function. It prevents reactive oxygen species-mediated lipid peroxidation and oxidative damage of DNA as evident from DNA nicking assay. Interestingly, chemical modification of the vicinal cysteines by phenylarsine oxide (PAO), a specific vicinal thiol modifier, significantly prevented this antioxidant activity. Modification of Cys-3 and Cys-4 was confirmed by MALDI-TOF mass spectroscopy of peptide fragments obtained after cyanogen bromide digestion of PAO-modified PfMIF. Furthermore, mutation of either Cys-3 or Cys-4 of PfMIF resulted in the loss of both Trx-like oxidoreductase and antioxidant activities of PfMIF. Altogether, our results suggest that the vicinal Cys-3 and Cys-4 play a critical role in the Trx-like oxidoreductase activity and antioxidant property of PfMIF.

    Item Type: Article
    URI: http://www.eprints.iicb.res.in/id/eprint/1262
    Subjects: Drug Development/Diagnostics & Biotechnology
    Infectious Diseases and Immunology
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Ms Sutapa Ganguly
    Date Deposited: 19 Jan 2012 12:13
    Last Modified: 19 Mar 2013 14:30
    Official URL: http://dx.doi.org/10.1016/j.freeradbiomed.2011.03....
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