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PDBsum entry 1ws3
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Oxidoreductase
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PDB id
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1ws3
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References listed in PDB file
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Key reference
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Title
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Urate oxidase from aspergillus flavus: new crystal-Packing contacts in relation to the content of the active site.
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Authors
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P.Retailleau,
N.Colloc'H,
D.Vivarès,
F.Bonneté,
B.Castro,
M.El hajji,
T.Prangé.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2005,
61,
218-229.
[DOI no: ]
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PubMed id
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Abstract
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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.
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Figure 1.
Figure 1
View of the active site: the omit map is contoured at the 1.5 [118][sigma] level around
the 5-amino-6-nitrouracil with the model superimposed. Graphics were created using
MOLSCRIPT (Kraulis, 1991[119] [Kraulis, P. E. (1991). J. Appl. Cryst. 24,
946-950.]-[120][bluearr.gif] ) and rendered using RASTER3D (Merritt & Murphy, 1994[121]
[Merritt, E. A. & Murphy, M. E. P. (1994). Acta Cryst. D50, 869-873.]-[122][bluearr.gif]
).
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Figure 2.
Figure 2
The reaction pathway from uric acid to 5-hydroxyisourate (middle) and the analogues used.
Note that uracil (and derivatives) standard numberings differ compared with uric acid
derivatives. *, Kahn & Tipton (1997[159] [Kahn, K. & Tipton, P. A. (1997). Biochemistry,
36, 4731-4738.]-[160][bluearr.gif] ); **, Pfleiderer (1974[161] [Pfleiderer, W. (1974).
Liebigs Ann. Chem. 12, 2030-2045.]-[162][bluearr.gif] ).
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(2005,
61,
218-229)
copyright 2005.
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Secondary reference #1
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Title
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Crystal structure of the protein drug urate oxidase-Inhibitor complex at 2.05 a resolution.
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Authors
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N.Colloc'H,
M.El hajji,
B.Bachet,
G.L'Hermite,
M.Schiltz,
T.Prangé,
B.Castro,
J.P.Mornon.
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Ref.
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Nat Struct Biol, 1997,
4,
947-952.
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PubMed id
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