Table 2.

Data Collection and Refinement Statistics

Human arginase I complex	nor-NOHA	NOHA	L-Lysine
Data Collection
Resolution, Å	50.0–1.55	50.0–2.04	50.0–1.90
Total/Unique reflections measureda	135232/90987	81841/40118	117869/49010
Rmergea,b	0.032 (0.302)	0.089 (0.186)	0.081 (0.433)
I/σ(I)a	14.4 (2.0)	28.9 (8.7)	17.4 (2.5)
Completeness (%)a	98.2 (96.2)	98.6 (91.8)	97.1 (98.9)
Refinement
Reflections used in refinement/test set	85281/4185	39744/1587	46106/1897
Rtwina,c	0.144	0.124	0.155
Rtwin/freea,c	0.178	0.174	0.204
Protein atomsd	4782	4782	4782
Water moleculesd	302	269	209
Inibitor atomsd	24	26	20
Manganese ionsd	4	4	4
R.m.s. deviations
Bond lengths, Å	0.006	0.006	0.006
Bond angles,°	1.34	1.29	1.33
Average B-factors, Å2
Main chain	18	26	23
Side chain	20	28	26
Manganese ions	13	17	18
Inhibitors	16	41	27
Solvent	23	30	25

^aNumber in parentheses refer to the outer 0.1 Å shell of data.

^bR_merge = Σ|I−〈I〉|/ΣI, where I is the observed intensity and 〈I〉 is the average intensity calculated for replicate data.

^cR_twin = Σ|[|F_calc/A|²⁺|F_calc/B|²]^1/2−|F_obs||/Σ|F_obs| for reflections contained in the working set. |F_calc/A| and |F_calc/B| are the structure factor amplitudes calculated for the separate twin domains A and B, respectively. R_twin underestimates the residual error in the model over the two twin-related reflections by a factor of approximately 0.7. The same expression describes R_twin/free, which was calculated for test set reflections excluded from refinement.

^dPer asymmetric unit.