Active site mutagenesis and phospholipid hydroperoxide reductase activity of poplar type II peroxiredoxin.
The nature of the active site and the substrate specificity of poplar type II peroxiredoxin, an enzyme which preferentially uses glutaredoxin as an electron donor, were investigated in this study. The type II peroxiredoxin is able to use phospholipid hydroperoxide nearly as efficiently as hydrogen peroxide. Two of the hyper-conserved amino acid residues in peroxiredoxins have been altered, by site-directed mutagenesis, generating the mutants T48V and R129Q. The two mutant proteins are inactive with hydrogen peroxide or tertiary butyl hydroperoxide as substrates. On the other hand, the mutant enzymes catalyse the degradation of cumene hydroperoxide with low efficiency. This suggests that the thiol-dependent regeneration process of the catalytic cysteine is not affected by the mutations and that all substrates are not accommodated identically in the active site.
Rouhier
Nicolas
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UMR 1136 Interaction Arbres Microorganismes INRA-UHP. Université Henri Poincaré, Faculté des Sciences BP 239, 54506 Vandoeuvre Cedex France LCM3B, Groupe Biocristallographie, UMR 7036, UHP, Faculté des Sciences, 54506 Vandoeuvre Cedex, France.
Gelhaye
Eric
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Corbier
Catherine
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Jacquot
Jean Pierre
JP