The facial triad in the α-ketoglutarate dependent oxygenase FIH: A role for sterics in linking substrate binding to O₂ activation.

ABSTRACT: The factor inhibiting hypoxia inducible factor-1α (FIH) is a nonheme Fe(II)/αKG oxygenase using a 2-His-1-Asp facial triad. FIH activates O₂ via oxidative decarboxylation of α-ketoglutarate (αKG) to generate an enzyme-based oxidant which hydroxylates the Asn⁸⁰³ residue within the C-terminal transactivation domain (CTAD) of HIF-1α. Tight coupling of these two sequential reactions requires a structural linkage between the Fe(II) and the substrate binding site to ensure that O₂ activation occurs after substrate binds. We tested the hypothesis that the facial triad carboxylate (Asp²⁰¹) of FIH linked substrate binding and O₂ binding sites. Asp²⁰¹ variants of FIH were constructed and thoroughly characterized in vitro using steady-

SUBMITTER: Hangasky JA 

PROVIDER: S-EPMC5161613 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature