1.4.4.2	hanging-drop vapour-difffusion method, crystals belong to the trigonal space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 89.5, c = 371.0 A	
1.4.4.2	purified recombinant His-tagged enzyme, hanging drop vapour diffusion, 18°C, 0.004 ml of 40/mg/ml protein in 20 mM Tris-HCl, pH 7.8, 50 mM sodium chloride, and 10 mM 2-mercaptoethanol, are mixed with 0.004 ml of reservoir solution containing 100 mM Tris-HCl pH 7.75, 15-25% PEG 3350, 0.15-0.3 M CsCl or LiCl and 10 mM 2-mercaptoethanol, equilibration over 1 ml reservoir solution, method optimization, 1-3 days, streak-seeding at 20°C, X-ray diffraction structure determination and analysis at 2.1 A resolution	
1.4.4.2	vapour diffusion method with 30% w/v polyethylene glycol 3350 and 100 mM KSCN as the precipitant. Crystal structure of three forms of P-protein: the apoenzyme at 2.4 A resolution, the holoenzyme at 2.1 A resolution and the holoenzyme in complex with a substrate analog inhibitor (aminooxy)acetate