Table 1. Data-collection and refinement statistics.

Values in parentheses are for the highest resolution shell.

Data collection
X-ray wavelength (Å)	0.9700
Space group	I222
Unit-cell parameters (Å)	a = 77.32, b = 100.26, c = 150.10
Resolution range (Å)	50.0–1.90 (1.97–1.90)
Unique reflections	40348
Completeness (%)	91.9 (84.7)
I/σ(I)	16.0 (4.5)
Rmerge†	0.070 (0.227)
Model refinement
Rwork/Rfree‡	0.170/0.214
No. of non-H atoms/average B factor (Å2)
Protein	3745/27.61
Waters	317/38.92
Phosphate ions	10/36.11
Sodium ions	2/16.61
R.m.s. deviations from ideal geometry
Bond lengths (Å)	0.014
Bond angles (°)	1.47
Ramachandran plot
Most favourable (%)	91.5
Allowed (%)	8.1
Generously allowed (%)	0.5
Disallowed (%)	0.0

^† R _merge = , where I(hkl) is the intensity of reflection hkl, is the sum over all reflections and is the sum over i measurements of reflection hkl.

^‡ R = , where R _free is calculated for a randomly chosen 5% of reflections which were not used for structure refinement and R _work is calculated for the remaining reflections.