Table 2. Refinement.

Space group	P43
Resolution range (Å)	19.9–2.8
No. of reflections (working/free)	17247/927
No. of protein residues	A, 96; B, 93; C, 92; D, 91; E, 84
No. of waters	40
No. of sulfate molecules	2
Rwork/Rfree (%)	24.0/29.9
Average B (Å2)	68.7
R.m.s. deviation from ideal values
Bond lengths (Å)	0.012
Bond angles (°)	1.6