O₂ Activation by Nonheme Fe^II α-Ketoglutarate-Dependent Enzyme Variants: Elucidating the Role of the Facial Triad Carboxylate in FIH.

ABSTRACT: FIH [factor inhibiting HIF (hypoxia inducible factor)] is an α-ketoglutarate (αKG)-dependent nonheme iron enzyme that catalyzes the hydroxylation of the C-terminal transactivation domain (CAD) asparagine residue in HIF-1α to regulate cellular oxygen levels. The role of the facial triad carboxylate ligand in O₂ activation and catalysis was evaluated by replacing the Asp201 residue with Gly (D201G), Ala (D201A), and Glu (D201E). Magnetic circular dichroism (MCD) spectroscopy showed that the (Fe^II)FIH variants were all 6-coordinate (6C) and the αKG plus CAD bound FIH variants were all 5-coordinate (5C), mirroring the behavior of the wild-type ( wt) enzyme. When only αKG is bound, all FIH variants exhibited weaker Fe^II-OH₂ bonds for the sixth ligand

SUBMITTER: Iyer SR 

PROVIDER: S-EPMC6146021 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature