1WS3

Urate oxidase from aspergillus flavus complexed with uracil

Summary for 1WS3

• Entry DOI: 10.2210/pdb1ws3/pdb
• Related: 1R51 1WS2
• Descriptor: Uricase, URACIL (2 entities in total)
• Functional Keywords: oxidoreductase, uric acid degradation, dimeric barrel, tunnel-shaped protein
• Biological source: Aspergillus flavus
• Cellular location: Peroxisome: Q00511
• Total number of polymer chains: 4
• Total formula weight: 137246.69

Authors

Retailleau, P.,Colloc'h, N.,Vivares, D.,Bonnete, F.,Castro, B.,El Hajji, M.,Prange, T. (deposition date: 2004-10-29, release date: 2005-03-22, Last modification date: 2023-10-25)

Primary citation

Retailleau, P.,Colloc'h, N.,Vivares, D.,Bonnete, F.,Castro, B.,El Hajji, M.,Prange, T.
Urate oxidase from Aspergillus flavus: new crystal-packing contacts in relation to the content of the active site.
Acta Crystallogr.,Sect.D, 61:218-229, 2005

PubMed Abstract: Urate oxidase from Aspergillus flavus (uricase or Uox; EC 1.7.3.3) is a 135 kDa homotetramer with a subunit consisting of 301 amino acids. It catalyses the first step of the degradation of uric acid into allantoin. The structure of the extracted enzyme complexed with a purine-type inhibitor (8-azaxanthin) had been solved from high-resolution X-ray diffraction of I222 crystals. Expression of the recombinant enzyme in Saccharomyces cerevisiae followed by a new purification procedure allowed the crystallization of both unliganded and liganded enzymes utilizing the same conditions but in various crystal forms. Here, four different crystal forms of Uox are analyzed. The diversity of the Uox crystal forms appears to depend strongly on the chemicals used as inhibitors. In the presence of uracil and 5,6-diaminouracil crystals usually belong to the trigonal space group P3(1)21, the asymmetric unit (AU) of which contains one tetramer of Uox (four subunits). Chemical oxidation of 5,6-diaminouracil within the protein may occur, leading to the canonical (I222) packing with one subunit per AU. Coexistence of two crystal forms, P2(1) with two tetramers per AU and I222, was found in the same crystallization drop containing another inhibitor, guanine. Finally, a fourth form, P2(1)2(1)2 with one tetramer per AU, resulted fortuitously in the presence of cymelarsan, an additive. Of all the reported forms, the I222 crystal forms present by far the best X-ray diffraction resolution (approximately 1.6 angstroms resolution compared with 2.3-3.2 angstroms for the other forms). The various structures and contacts in all crystalline lattices are compared. The backbones are essentially conserved except for the region near the active site. Its location at the dimer interface is thus likely to be at the origin of the crystal contact changes as a response to the various bound inhibitors.

PubMed: 15735331
DOI: 10.1107/S0907444904031531

Experimental method

X-RAY DIFFRACTION (3.2 Å)