Table 2. X-ray data collection and refinement statistics.

Data collection
Beamline	SSRL 12-2
Wavelength (Å)	0.9795
Space group	P43
Unit cell parameters (Å)	a=b=88.3, c=255.0
Resolution (Å)	50-1.97 (2.04-1.97)*
Unique reflections	136,341 (13,627)*
Redundancy	6.3 (6.2)*
Completeness (%)	99.5 (99.5)*
<I/σI>	15.4 (2.0)*
Rsym†	0.16 (0.82)*
Rpim†	0.07 (0.35)*
CC1/2‡	0.99 (0.72)*
Za§	2
Refinement statistics
Resolution (Å)	50–1.97
Reflections (work)	130,202
Reflections (test)	6,751
Rcryst(%)‖/Rfree(%)¶	18.1/20.8
No. of atoms
Protein
HA1	3,987
Fab	6,846
Water	1,113
Ion	1
Glycan	56
Other#	90
Average B-value (Å2)
Protein
HA1	37.2
Fab	30.5
Water	40.0
Ion	46.3
Glycan	74.4
Other#	77.2
Wilson B-value (Å2)	22.7
R.m.s.d. from ideal geometry
Bond length (Å)	0.013
Bond angle (°)	1.60
Ramachandran statistics (%)**
Favored	96.7
Outliers	0.2

r.m.s.d., root mean squared deviation.

^*Numbers in parentheses refer to the highest resolution shell.

^†R_sym=Σ_hklΣ_i|I_hkl,i−<I_hkl>|/Σ_hklΣ_iI_hkl,i and R_pim=Σ_hkl(1/(n−1))^1/2 Σ_i|I_hkl,i−<I_hkl>|/Σ_hklΣ_iI_hkl,i, where I_hkl,i is the scaled intensity of the i^th measurement of reflection h, k, l, <I_hkl> is the average intensity for that reflection, and n is the redundancy.

^‡CC_1/2=Pearson correlation coefficient between two random half datasets.

^§Z_a is the number of HA1-Fab complexes per crystallographic asymmetric unit.

^‖R_cryst=Σ_hkl|F_o−F_c|/Σ_hkl|F_o| × 100, where F_o and F_c are the observed and calculated structure factors, respectively.

^¶R_free was calculated as for R_cryst, but on a test set comprising 5% of the data excluded from refinement.

^#Other includes non-water solvent and cryoprotectant.

^**Calculated with MolProbity⁶³.