Table 1. Data collection and refinement statistics.

AS, ammonium sulphate; AA, ammonium acetate; NaCit, sodium citrate; PEG, poly(ethylene glycol); a.u., asymmetric units. R_work and R_free are defined as follows:

Data in parentheses are for the final 0.1 Å.

Crystal form…	1	2	3	4	5
Crystallization
Crystallization buffer	pH 6.3	pH 7.4	pH 7.0	pH 6.6	pH 7.9
	0.2 M AS	10% propan-2-ol	0.2 M CaCl2	0.2 M AA	1.2M NaCit
	30% PEG8000	20% PEG4000	25% PEG4000	2.0M K/NaPi
Data collection
Space group	P21	P212121	P3121	P3121	P3221
Unit cell (Å, °)	a=59.7, b=34.4, c=74.3; β=94.2	a=33.8, b=59.6, c=64.3	a=b=46.0, c=122.8	a=b=60.2, c=87.7	a=b=60.0, c=172.4
Resolution (Å)	30.0–1.55	30.0–1.85	30.0–1.60	30.0–1.35	30.0–1.72
Reflections
Unique	43301	11016	20371	41043	39263
Redundancy	3.8	2.5	3.5	5.4	4.7
Completeness (%)	97.9 (95.2)	94.6 (94.8)	98.4 (95.6)	99.9 (99.9)	99.6 (99.5)
I/σ(I)	28.7 (1.6)	20.6 (3.1)	21.4 (3.5)	38.1 (3.4)	37.6 (2.9)
Rsym	0.072 (0.616)	0.068 (0.253)	0.071 (0.323)	0.072 (0.358)	0.069 (0.373)
Refinement
Resolution (Å)	20.0–1.55	20.0–1.85	20.0–1.60	20.0–1.35	20.0–1.72
Reflections (number/%)	40560/96.7	10471/94.9	20345/98.5	40933/99.7	39095/99.6
Test set (%)	5	5	5	5	5
Rworkd	0.235	0.224	0.187	0.199	0.217
Rfreed	0.251	0.253	0.223	0.214	0.249
Content of a.u.
Protein molecules	2	1	1	1	2
Protein atoms	2362	1175	1196	1188	2376
Water atoms	392	137	264	288	238
Ligands	2 sulphate ions	1 sulphate ion	1 calcium ion	–	2 citrate ions
Mean B-factors (Å2)
Wilson	26.2	27.6	19.4	19.4	33.3
Protein	24.7	27.9	19.3	22.7	26.5
Water	45.8	49.8	35.2	39.3	56.8
Ligands	80.2	79.3	14.7	–	91.4
Ramachandran plot
Preferred	0.992	0.984	0.992	0.992	1.000
Additions allowed	0.8	0.8	0.8	0.0	0.0
Disallowed	0.0	0.8	0.0	0.8	0.0
Rmsd geometry
Bond length (Å)	0.009	0.010	0.007	0.008	0.008
Bond angle (°)	1.18	1.02	1.40	1.27	1.08
Rmsd B-factors (Å2)
Main-chain bonds	1.4	1.27	2.7	2.4	1.3
Main-chain angles	2.2	2.42	3.3	3.3	2.2
Side-chain bonds	1.6	3.40	5.3	4.6	1.5
Side-chain angles	2.3	5.83	6.6	5.9	2.5
PDB entry	1TZT	1TZU	1TZW	1TZV	1TZX