Table 2. Refinement and model statistics.

Resolution ()	2.0
Final R factor† (%)
Working set	21.0
Working set + test set	21.12
R free ‡ (%)	24.65
R.m.s.d. bond lengths ()	0.01
R.m.s.d. bond angles ()	1.22
Mean B value (2)
Main-chain atoms	25.5
Side-chain atoms	28.7
Solvent content (%)	51.87
No. of protein residues	168
No. of glycerol molecules	6
No. of water molecules	135
Ramachandran plot (% of residues in)
Most favoured regions	98.2
Additionally allowed regions	1.8
Disallowed regions	0

^† R = , where F _obs and F _calc are the observed and calculated structure factors, respectively.

^‡ R _free was determined using 5% of the data (Brnger, 1992 ▶).