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

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