Table 1. Crystallization.

Variant	D499N	W527H	GGG	S531E
Method	All crystals were grown by hanging-drop vapor diffusion at 298 K in VDX 24-well plates
Protein concentration (mg ml−1)	3.6	6.0	2.0	2.0
Buffer composition of protein solution	50 mM MES pH 6.8, 100 mM KCl, 10% glycerol, 2 mM DTT	50 mM MES pH 6.8, 100 mM KCl, 10% glycerol, 2 mM DTT	50 mM MES pH 6.8, 100 mM KCl, 10% glycerol, 2 mM DTT	50 mM MES pH 6.8, 100 mM KCl, 10% glycerol, 2 mM DTT
Composition of reservoir solution	200 mM ammonium citrate dibasic, 20% PEG 3350	325 mM ammonium citrate dibasic, 16% PEG 3350	200 mM ammonium citrate pH 6.0, 24% PEG 3350	200 mM ammonium citrate pH 5.6, 16% PEG 3350
Volume and ratio of drop	3.0 µl, 1:1	3.0 µl, 1:1	3.0 µl, 1:1	3.0 µl, 1:1
Volume of reservoir (µl)	1000	1000	1000	1000