2.6.1.18 diffraction to 1.7 A. Space group P1 2.6.1.18 microbatch method using either 0.05 M HEPES pH 7.5, 5% (v/v) 2-propanol, 10%(w/v) PEG 4000 or 0.1 M lithium sulfate monohydrate, 0.05 M Tris-HCl pH 8.5, 15% (w/v) PEG 4000 2.6.1.18 protein forms a dimer containing a large activesite pocket and unusual phosphorylated histidine residues