Table 1.
Cryo-EM data collection, refinement and validation statistics
| AN mono (α sat) (EMDB-26330) (PDB 7U46) | AN stack (α sat) (EMDB-26331) (PDB 7U47) | AN stack (601) (EMDB-26332) (PDB 7U4D) | AN 12-mer (601) (EMDB-26333) | |
|---|---|---|---|---|
| Data collection and processing | ||||
| Magnification | 29,000 | 29,000 | 22,500 | |
| Voltage (kV) | 300 | 300 | 300 | |
| Electron exposure (e–/Å2) | 70 | 80 | 100 | |
| Defocus range (μm) | 0.8–2.0 | 1.0–2.5 | 1.3–2.5 | |
| Pixel size (Å) | 0.8211 | 1.02 | 0.655 | |
| Symmetry imposed | C1 | C1 | C1 | |
| Initial particle images (no.) | 555,254 | 292,321 | 13,356 | |
| Final particle images (no.) | 314,239 | 88,530 | 174,936 | 9,305 |
| Map resolution (Å) | 2.68 | 3.54 | 5.30 | 12.70 |
| FSC threshold | 0.143 | 0.143 | 0.143 | 0.143 |
| Map resolution range (Å) | 2.5–4.5 | 3.5–10 | 5.0–12.0 | 12.5–28.0 |
| Refinement | ||||
| Initial model used (PDB code) | 1KX5, 6C0W | 6C0W | ||
| Model resolution (Å) | 2.7 | 3.8a | 5.9a | |
| FSC threshold | 0.143 | 0.143 | 0.143 | |
| Model resolution range (Å) | 2.5–4.5 | 3.5–9.4 | 5.9–11.9 | |
| Map sharpening B factor (Å2) | ||||
| Model composition | ||||
| Non-hydrogen atoms | 13,362 | 26,724 | 262,444 | |
| Protein residues | 925 | 1,850 | 1,850 | |
| Nucleotide | 290 | 580 | 556 | |
| Ligands | 0 | 0 | 0 | |
| B factors (Å2) | ||||
| Protein | 77.09 | 77.09 | 65.96 | |
| Nucleotide | 108.23 | 108.23 | 121.56 | |
| Ligand | n/a | n/a | n/a | |
| R.m.s. deviations | ||||
| Bond lengths (Å) | 0.011 | 0.011 | 0.006 | |
| Bond angles (°) | 0.781 | 0.913 | 0.972 | |
| Validation | ||||
| MolProbity score | 1.38 | 1.4 | 1.58 | |
| Clashscore | 4.10 | 4.41 | 4.65 | |
| Poor rotamers (%) | 0.00 | 0.00 | 0.00 | |
| Ramachandran plot | ||||
| Favored (%) | 96.91 | 96.91 | 95.08 | |
| Allowed (%) | 3.09 | 3.09 | 4.92 | |
| Disallowed (%) | 0.00 | 0.00 | 0.00 | |
aDue to severe orientation issues, the reported resolution is not an accurate reflection of the map quality.