Oxygen pressurized X-ray crystallography: probing the dioxygen binding site in cofactorless urate oxidase and implications for its catalytic mechanism.

ABSTRACT: The localization of dioxygen sites in oxygen-binding proteins is a nontrivial experimental task and is often suggested through indirect methods such as using xenon or halide anions as oxygen probes. In this study, a straightforward method based on x-ray crystallography under high pressure of pure oxygen has been developed. An application is given on urate oxidase (UOX), a cofactorless enzyme that catalyzes the oxidation of uric acid to 5-hydroxyisourate in the presence of dioxygen. UOX crystals in complex with a competitive inhibitor of its natural substrate are submitted to an increasing pressure of 1.0, 2.5, or 4.0 MPa of gaseous oxygen. The results clearly show that dioxygen binds within the active site at a location where a water molecule is usually observed but does not bind in the al

SUBMITTER: Colloc'h N 

PROVIDER: S-EPMC2517026 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature