Table 1.

Data collection and refinement statistics of IgG^GAR Fab

Space group	P212121
Unit cell, Å	a = 100.6, b = 111.1, c = 188.5
Resolution, Å	50.0–3.00 (3.07–3.00)*
X-ray source	SSRL 11–1
No unique reflections	42,610
Redundancy	3.8 (3.7)
Average I/σ(I)	15.5 (2.1)*
Completeness	98.9 (99.3)*
Rmerge†	0.10 (0.81)*
Refined residues	1,716
Refined waters‡	144
Rcryst§	0.240
Rfree¶	0.290
Average B values, Å2
Protein	61.4
Waters	33.9
Ligands	67.5
Ramachandran plot, %∥	83.0, 16.5, 0.3, 0.3
rmsd Bond lengths, Å	0.009
rmsd Bond angles, °	1.6

rmsd, rms deviation.

*Parentheses denote outer-shell statistics.

^†R_merge = Σ_hΣ_i |I_i(h) − 〈I(h)〉|/Σ_hΣ_i I_i (h), where 〈I(h)〉 is the average intensity of i symmetry-related observations of reflections with Bragg index h.

^‡Although it is unusual to refine many waters at this resolution, many were unambiguous and refined well. The 144 waters bind to four Fab molecules in the asymmetric unit.

^§R_cryst = Σ_hkl |F_o − F_c|/Σ_hkl |F_o|, where F_o and F_c are the observed and calculated structure factors.

^¶R_free was calculated as for R_cryst but on 5% of data excluded before refinement.

^∥The values are percentages of residues in the most favored, additional allowed, generously allowed, and disallowed regions. Asp^L51, as expected, shows main-chain torsion angles in the disallowed regions but in a well defined γ-turn that is observed in most antibody structures (6).