Crystallization and preliminary X-ray analysis of a Y13S mutant of Spo0F from Bacillus subtilis

Spo0F, a member of a superfamily of bacterial response regulatory proteins, is crucial to the regulation of sporulation in Bacillus subtilis. As there were difficulties in reproducing crystals of wild-type Spo0F, we report here the crystallization and preliminary studies of a mutant, Y13S protein, which gave well diffracting reproducible crystals. The crystals of the mutant obtained by the hanging-drop method belong to the tetragonal space group P4(1)2(1)2 (P4(3)2(1)2) a = b = 105.1, c = 85.9 A. Diffraction data were collected at 2.8 A at the laboratory source and subsequently 2.05. A data were collected upon flash freezing the crystal at the Stanford Synchrotron Radiation Laboratory. This mutant participates in the phosphorelay in a similar manner to the wild-type protein. The presence of divalent cations are essential for wild-type phosphorylation and the present mutant crystal form is obtained in the presence of calcium.