Table 2. Refinement statistics.

Resolution range (Å)	64.3–2.25
No. of reflections	28683
No. of protein atoms per ASU	3843
No. of water molecules per ASU	265
Average B factor (Å2)
Protein atoms	34.8
Water molecules	38.1
Glycerol molecules	52.6
Azide ions	50.3
Sulfate ions	50.3
Rcryst (%) (all reflections)	19.1
Rfree (%) (5% of reflections)	22.6
R.m.s.d. bond lengths (Å)	0.014
R.m.s.d. bond angles (°)	1.37
σA coordinate error (Å)	0.29
Ramachandran plot analysis (structure analysed with MolProbity)
No. of residues in favoured regions (%)	97.9
No. of residues in allowed regions (%)	99.8
Outliers (%)	0.2