Crystallization and preliminary X-ray analysis of clade I catalases from Pseudomonas syringae and Listeria seeligeri

Haem-containing catalases are homotetrameric molecules that degrade hydroge n peroxide. Phylogenetically, the haem-containing catalases can be grouped into three main lines or clades. The crystal structures of seven catalases have been determined, all from clades II and III. In order to obtain a stru cture of an enzyme from clade I, which includes all plant, algae and some b acterial enzymes, two bacterial catalases, CatF from Pseudomonas syringae a nd Kat from Listeria seeligeri, have been crystallized by the hanging-drop vapour-diffusion technique, using PEG and ammonium sulfate as precipitants, respectively. Crystals of P. syringae CatF, with a plate-like morphology, belong to the monoclinic space group P2(1), with unit-cell parameters a = 6 0.6, b = 153.9, c = 109.2 Angstrom, beta = 102.8 degrees. From these crysta ls a diffraction data set to 1.8 Angstrom resolution with 98% completeness was collected using synchrotron radiation. Crystals of L. seeligeri Kat, wi th a well developed bipyramidal morphology, belong to space group I222 (or I2(1)2(1)2(1)), with unit-cell parameters a = 74.4, b = 121.3, c = 368.5 An gstrom. These crystals diffracted beyond 2.2 Angstrom resolution when using synchrotron radiation, but presented anisotropic diffraction, with the wea kest direction perpendicular to the long c axis.