Purification, crystallization and preliminary crystallographic analysis of RecA superfamily ATPase PH0284 from Pyrococcus horikoshii OT3

RecA superfamily ATPase PH0284 from P. horikoshii OT3 was overexpressed, purified, crystallized and cocrystallized with ATP. Both crystal forms belong to the trigonal space group P3₂21 and diffract X-rays to 2.0 and 2.3 Å resolution, respectively. Circadian (daily) protein clocks are found in cyanobacteria, where a complex of the KaiA, KaiB and KaiC proteins generates circadian rhythms. The 28.09 kDa KaiC homologue PH0284 protein from Pyrococcus horikoshii OT3 was cloned and expressed and the purified protein was crystallized by the oil-microbatch method at 295 K. X-ray diffraction data from the crystal were collected to 2.0 Å resolution using synchrotron radiation at 100 K. The crystal belongs to the trigonal space group P3₂21, with unit-cell parameters a = b = 96.06, c = 298.90 Å. Assuming the presence of one hexamer in the asymmetric unit gives a V_M value of 2.36 ų Da⁻¹ and a solvent content of 47.9%. A cocrystal with ATP was prepared and a diffraction data set was collected at 2.3 Å resolution