4CW6: Crystal structure of cofactor-free urate oxidase in complex with the 5-peroxo derivative of 9-metyl uric acid (X-ray dose, 92 kGy)

Citation:
Abstract
Cofactor-free oxidases and oxygenases promote and control the reactivity of O2 with limited chemical tools at their disposal. Their mechanism of action is not completely understood and structural information is not available for any of the reaction intermediates. Near-atomic resolution crystallography supported by in crystallo Raman spectroscopy and QM/MM calculations showed unambiguously that the archetypical cofactor-free uricase catalyzes uric acid degradation via a C5(S)-(hydro)peroxide intermediate. Low X-ray doses break specifically the intermediate C5-OO(H) bond at 100 K, thus releasing O2 in situ, which is trapped above the substrate radical. The dose-dependent rate of bond rupture followed by combined crystallographic and Raman analysis indicates that ionizing radiation kick-starts both peroxide decomposition and its regeneration. Peroxidation can be explained by a mechanism in which the substrate radical recombines with superoxide transiently produced in the active site.
PDB ID: 4CW6Download
MMDB ID: 124289
PDB Deposition Date: 2014/4/1
Updated in MMDB: 2014/12
Experimental Method:
x-ray diffraction
Resolution: 1.28  Å
Source Organism:
Similar Structures:
Biological Unit for 4CW6: tetrameric; determined by software (PISA)
Molecular Components in 4CW6
Label Count Molecule
Proteins (4 molecules)
4
Uricase
Molecule annotation
Chemicals (16 molecules)
1
4
2
4
3
4
4
4
* Click molecule labels to explore molecular sequence information.

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