Biochemical and electron paramagnetic resonance study of the iron superoxide dismutase from Plasmodium falciparum
| Autor: | René Wintjens, Marc Fontecave, Danièle Touati, Stéphane Ménage, Daniel Camus, Annick Masset, Patrick Delplace, Daniel Dive, Sylvie Gratepanche |
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| Rok vydání: | 2002 |
| Předmět: |
Models
Molecular Time Factors Protein Conformation Iron Protein subunit Plasmodium falciparum medicine.disease_cause Mass Spectrometry law.invention Superoxide dismutase Mutant protein law Enzyme Stability medicine Animals Electron paramagnetic resonance Molecular Biology Escherichia coli chemistry.chemical_classification biology Superoxide Dismutase Mutagenesis Electron Spin Resonance Spectroscopy Temperature Hydrogen Peroxide biology.organism_classification Enzyme Activation Molecular Weight Enzyme Biochemistry chemistry Mutation biology.protein Parasitology |
| Zdroj: | Molecular and Biochemical Parasitology. 120:237-246 |
| ISSN: | 0166-6851 |
| Popis: | Recombinant iron-containing superoxide dismutase (Fe-SOD) from Plasmodium falciparum was produced in a SOD-deficient strain of Escherichia coli, purified and characterised. The enzyme is a dimer, which contains 1.7 Fe equivalents and is sensitive to hydrogen peroxide (H(2)O(2)). Electron paramagnetic resonance (EPR) analysis showed two different signals, reflecting the presence of two different types of high-spin Fe sites with different symmetries. The role of the W71 residue during inactivation by H(2)O(2) of the P. falciparum Fe-SOD was studied by site-directed mutagenesis. First, the W71V mutation led to a change in the relative proportion of the two Fe-based EPR signals. Second, the mutant protein was almost as active as the wild-type (WT) protein but more sensitive to heat inactivation. Third, resistance to H(2)O(2) was only slightly increased indicating that W71 was marginally responsible for the sensitivity of Fe-SOD to H(2)O(2). A molecular model of the subunit was designed to assist in interpretation of the results. The fact that the parasite SOD does not belong to classes of SOD present in humans may provide a novel approach for the design of antimalarial drugs. |
| Databáze: | OpenAIRE |
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