Table 1.

Crystallography data and refinement statistics

Crystal form:		Low-formate	High-formate
Crystal parameters:
Space group		P212121	P212121
Cell dimensions
a, b, c (Å)		99.83, 100.90 , 192.34	99.78, 100.46 , 192.96
α, β, γ (°)		90, 90, 90	90, 90, 90
Data quality:
Resolution (Å)		50 – 2.13	50 – 2.5
Rsym		0.11 (0.72)	0.17 (0.63)
Mean redundancy		7.2	7.3
Completeness		94.60%	98.60%
Mean I/σ(I)		12.43 (2.1)	14.6 (2.6)
Phasing Statistics:
Anomalous signal (Å)		5.4
Mean figure of merit		0.52
Refinement:
Resolution (Å)		50 – 2.13	50 – 2.5
No. reflections		102,406	62,189
Rwork/ Rfree		0.18 / 0.21	0.17 / 0.22
Average B-factor (Å2)
Protein		68.91	55.76
Formate, octylglucoside		99.94	81.70
Water		58.46	45.64
R.M.S deviations
Bond lengths (Å)		0.008	0.008
Bond angles (°)		0.995	1.026
Model Contents:
		Monomer A: 256	Monomer A: 257
		Monomer B: 254	Monomer B: 255
Protein residues		Monomer C: 259	Monomer C: 254
		Monomer D: 251	Monomer D: 254
		Monomer E: 255	Monomer E: 256
Ligands		16 β-OG	13 β-OG, 51 formate *
Water molecules		346	227

Notes:

R_sym = S|I_j – <I_j>|/SI_j, where <I_j> is the averaged intensity for symmetry related reflections. Redundancy represents the ratio between the number of measurements and the number of unique reflections. R factor = S|F(obs) – F(cal)|/SF(obs); 5% of the data that were excluded from the refinement were to calculate R_free. The average B factor was calculated for all non-hydrogen atoms. r.m.s.d. of bond is the root-mean-square deviation of the bond angle and length. Numbers in parentheses are statistics of the highest resolution shell.

^*While two formate ions are found at the selectivity filter of Monomer E, one is found at that of Monomer D. The rest of the formate ions are found on the protein surface.