Spectroscopic and Computational Investigation of the H155A Variant of Cysteine Dioxygenase: Geometric and Electronic Consequences of a Third-Sphere Amino Acid Substitution.

ABSTRACT: Cysteine dioxygenase (CDO) is a mononuclear, non-heme iron(II)-dependent enzyme that utilizes molecular oxygen to catalyze the oxidation of l-cysteine (Cys) to cysteinesulfinic acid. Although the kinetic consequences of various outer-sphere amino acid substitutions have previously been assessed, the effects of these substitutions on the geometric and electronic structures of the active site remained largely unexplored. In this work, we have performed a spectroscopic and computational characterization of the H155A CDO variant, which was previously shown to display a rate of Cys oxidation ∼100-fold decreased relative to that of wild-type (WT) CDO. Magnetic circular dichroism and electron paramagnetic resonance spectroscopic data indicate that the His155 → Ala substitution has a significant e

SUBMITTER: Blaesi EJ 

PROVIDER: S-EPMC4642275 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature