Comparison of Spatial Structures and Packaging of Phosphorybosil Pyrophosphate Synthetase 2 from Thermus thermophilus HB27 in Rhombohedral and Tetragonal Crystals

We report the spatial structure of phosphoribosyl pyrophosphate synthetase 2 from the thermophilic bacterium Thermus thermophilus HB27 (TthPRPPS2) obtained at a 1.85 angstrom resolution using a diffraction set collected from rhombohedral crystals (space group R3(2)-h), grown with lithium sulfate as a precipitant. This crystal structure was compared with the structure of TthPRPPS2, previously obtained at a 2.2 angstrom resolution using diffraction sets from the tetragonal crystals (space group P4(1)2(1)2), grown with ammonium sulfate as a precipitant. The comparison of these structures allows the study of the differences between protein molecules in both crystalline structures, as well as the packaging of enzyme molecules in crystals of both spatial groups. Our results may contribute to the research of the structural basis of catalytic activity and substrate specificity of this enzyme.