Purification, crystallization and phase determination of the DR1998 haembcatalase fromDeinococcus radiodurans

Abstract

The protective mechanisms ofDeinococcus radioduransagainst primary reactive oxygen species involve nonenzymatic scavengers and a powerful enzymatic antioxidant system including catalases, peroxidases and superoxide dismutases that prevents oxidative damage. Catalase is an enzyme that is responsible for the conversion of H2O2to O2and H2O, protecting the organism from the oxidative effect of H2O2. This study reports the purification and crystallization of the DR1998 catalase fromD. radiodurans. The crystals diffracted to 2.6 Å resolution and belonged to space groupC2221, with unit-cell parametersa= 97.33,b= 311.88,c= 145.63 Å, suggesting that they contain four molecules per asymmetric unit. The initial phases were determined by molecular replacement and the obtained solution shows the typical catalase quaternary structure. A preliminary model of the protein structure has been built and refinement is currently in progress.