Table 1.

Diffraction data and refinement statistics

Beam line measurement	Data set 1, ID14-EH2	Data set 2, ID13
Wavelength, Å	0.933	0.964
Resolution, Å	2.1	2.3
Unit cell, Å*	84.8, 128.7, 50.7	85.9, 129.8, 51.2
Mosaicity, °	1.7	0.5
No. of observations	99,617	43,109
No. of unique reflections	15,962	12,594
Rsym, %† (outer shell)‡	7.2 (42.5)	8.5 (38.4)
I/σ (I) (outer shell)‡	8.4 (1.8)	7.2 (1.8)
Completeness (outer shell)‡	96.1 (80.1)	96.7 (96.4)
Wilson B factor, Å2	23.7	19.9
Number of atoms
Total (protein, retinal, ion, water)	1,682 (1,634, 20, 1, 27)	1670 (1623, 20, 1, 26)
Average B factors, Å2
Total (protein, retinal, ion, water)	37.3 (37.3, 28.2, 38.1, 40.3)	31.1 (31.1, 20.9, 34.2, 33.2)
Rcryst, %§ (outer shell)¶	23.7 (27.3)	22.7 (23.2)
Rfree, %‖ (outer shell)¶	25.6 (29.5)	24.2 (24.7)
rmsd of bond lengths, Å, and angles, °	0.006, 1.0	0.007, 1.0

Data set 1 was taken on the ID-EH2 beam line; data set 2 was taken on the ID13 beam line. 

^*The space group is C222₁. 

^† R_sym = Σ_jΣ_h|I_h,j − 〈I_h〉|/Σ_jΣ_h I_h,j. 

^‡ Outer shells were 2.21/2.10 Å and 2.42/2.30 Å for data sets 1 and 2, respectively. 

^§ R_cryst = Σ_h∥F_obs(h)| − |F_calc(h)∥/Σ_h|F_obs(h)|. 

^¶ Outer shells for refinement were 2.23/2.10 Å and 2.44/2.30 Å for data sets 1 and 2, respectively. 

^‖ Calculated from a set of 5% randomly selected reflections that were excluded from refinement.