Role of Proximal Methionine Residues in Leishmania Major Peroxidase

Yadav, Rajesh K and Pal, Swati and Dolai, Subhankar and Adak, Subrata (2011) Role of Proximal Methionine Residues in Leishmania Major Peroxidase. Archives of Biochemistry and Biophysics, 512. pp. 21-27.


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    The active site architecture of Leishmania major peroxidase (LmP) is very similar with both cytochrome c peroxidase and ascorbate peroxidase. We utilized point mutagenesis to investigate if the conserved proximal methionine residues (Met248 and Met249) in LmP help in controlling catalysis. Steady-state kinetics of methionine mutants shows that ferrocytochrome c oxidation is <2% of wild type levels without affecting the second order rate constant of first phase of Compound I formation, while the activity toward a small molecule substrate, guaiacol or iodide, increases. Our diode array stopped-flow spectral studies show that the porphyrin p-cation radical of Compound I in mutant LmP is more stable than wild type enzyme. These results suggest that the electronegative sulfur atoms of the proximal pocket are critical factors for controlling the location of a stable Compound I radical in heme peroxidases and are important in the oxidation of ferrocytochrome c.

    Item Type: Article
    Subjects: Structural Biology & Bioinformatics
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Mr Shyamal Nath
    Date Deposited: 27 Dec 2011 14:39
    Last Modified: 27 Dec 2011 14:39
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