Crystallization and preliminary crystallographic analysis of creatininase from Pseudomonas putida

Creatininase (CrnA) from Pseudomonas putida is a homohexameric heat-stable enzyme composed of 259 amino acids per subunit. The molecular weight of each monomer is 28.4 kDa. The enzyme hydrolyses creatinine to yield creatine. Crystals of this protein have been grown from ethanol/PEG 8000. They belong to the monoclinic space group P2(1), with unit-cell parameters a = 74.8, b = 95.7, c = 116.9 A, alpha = gamma = 90, beta = 103.8 degrees. The diffraction limit is 2.5 A. The self-rotation function of the native data set is consistent with a CrnA hexamer in the asymmetric unit and suggests D(3) point-group symmetry of the enzyme.