N. Colloch et al., CRYSTAL-STRUCTURE OF THE PROTEIN DRUG URATE OXIDASE-INHIBITOR COMPLEXAT 2.05 ANGSTROM RESOLUTION, Nature structural biology, 4(11), 1997, pp. 947-952
The gene coding for urate oxidase, an enzyme that catalyzes the oxidat
ion of uric acid to allantoin, is inactivated in humans. Consequently,
urate oxidase is used as a protein drug to overcome severe disorders
induced by uric acid accumulation. The structure of the active homotet
rameric enzyme reveals the existence of a small architectural domain t
hat we call T-fold (for tunnelling-fold) domain. It assembles to form
a perfect unusual dimeric alpha 8 beta 16 barrel. Urate oxidase may be
the archetype of an expanding new family of tunnel-shaped proteins th
at now has three members; tetrahydropterin synthase, CTP cyclohydrolas
e I and urate oxidase. The structure of the active site of urate oxida
se around the 8-azaxanthine inhibitor reveals an original mechanism of
oxidation that does not require any ions or prosthetic groups.