title: Purification, crystallization and phase determination of the DR1998 haem b catalase from Deinococcus radiodurans.
abstract: The protective mechanisms of Deinococcus radiodurans against 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 H2O2 to O2 and H2O, protecting the organism from the oxidative effect of H2O2. This study reports the purification and crystallization of the DR1998 catalase from D. radiodurans. The crystals diffracted to 2.6 Å resolution and belonged to space group C2221, with unit-cell parameters a = 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.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: Patrícia T
authors.initials: PT
authors.lastname: Borges
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: Cecília S
authors.initials: CS
authors.lastname: Miranda
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: Sandra P
authors.initials: SP
authors.lastname: Santos
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: João N
authors.initials: JN
authors.lastname: Carita
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Frazão
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Estação Agronómica Nacional, 2780-157 Oeiras, Portugal.
authors.forename: Célia V
authors.initials: CV
authors.lastname: Romão
mesh_terms: D002374:Catalase / Q000737:chemistry* / Q000302:isolation & purification; D003460:Crystallization; D034301:Deinococcus / Q000201:enzymology*; D006418:Heme / Q000737:chemistry* / Q000302:isolation & purification; D017434:Protein Structure, Tertiary
chemical_list: D006418:Heme; D002374:Catalase
keywords: bacteria; metalloproteins; reactive oxygen species