Table 1.

Cryo-EM data collection and model refinement statistics.

Data collection and processingpH-7 datasetpH-5 datasetpH-3 dataset
MicroscopeFEI Titan KriosFEI Titan KriosFEI Titan Krios
Magnification165,000165,000165,000
Voltage (kV)300300300
Electron exposure (e2)∼50∼50∼50
Defocus range (μm)2.0–3.82.0–3.82.0–3.8
Pixel size (Å)0.820.820.83
Symmetry imposedC5C5C5
Number of images∼5,300∼7,000∼6,400
Particles picked∼700,000∼1 million∼690,000
Particles refined86,201351,643214,463
Refinement
 Initial model used4NPQ monomer4NPQ monomer4NPQ monomer
 Resolution (Å)4.13.43.6
  FSC threshold0.1430.1430.143
 Map sharpening B-factor−278−223−225
Model composition
 Non-hydrogen protein atoms10,17511,55511,630
 Protein residues1,4401,5401,535
Ligands000
 B-factor (Å2)572034
Root mean-squared deviation
 Bond Lengths (Å)0.0060.0050.006
 Bond angles (°)0.6160.5990.664
Validation
 MolProbity score1.871.931.77
 Clashscore10.739.666.12
 Poor rotamers (%)000
Ramachandran plot
 Favored (%)95.493.793.4
 Allowed (%)4.66.36.6
 Outliers (%)000