Table 1.
Data collection, refinement, and validation statistics
| Data collection | |
| Microscope | Titan Krios S‐FEG |
| Camera | CMOS (Falcon II) |
| Voltage (kV) | 300 |
| Magnification | 59,000× |
| Pixel size (Å.px−1) | 1.1 |
| Defocus range (μm) | (−4.5) – (−0.6) |
| Total dose (ē/Å2) | 60 |
| Dose per frame | ~3.5 |
| Refinement | (tight; loose) dimer/(unrotated; rotated) monomer |
| Number of particles (total) | 132,000/348,000 |
| Number of particles (used for 3D reconstruction) | 17,500; 17,300/83,000; 80,000 |
| Resolution (Å; at FSC = 0.143) | 11.0; 9.0/3.7; 3.7 |
| CC (model to map fita) | n.d.; n.d./0.73; 0.74 |
| Model composition | (unrotated; rotated) monomer |
| Non‐hydrogen atoms | 141,613; 141,636 |
| Residues | 10,090; 10,093 |
| RMS deviations | |
| Bonds (Å) | 0.01; 0.01 |
| Angles (°) | 1.08; 1.2 |
| Chirality (°) | 0.05; 0.08 |
| Planarity (°) | 0.005; 0.007 |
| Validation b | |
| Clashscorec | 6.48 (89th p.); 7.82 (82nd p.) |
| Proteins | |
| MolProbity score | 2.06 (72nd p.); 2.16 (67th p.) |
| Favored rotamers | 4,502 (96.22%); 4,400 (94.00%) |
| Ramachandran favored | 4,449 (82.28%); 4,343 (80.28%) |
| Ramachandran allowed | 923 (17.26%); 1,040 (19.22%) |
| Ramachandran outliers | 25 (0.46%); 25 (0.5%) |
| RNA | |
| Correct sugar puckers | 99.78%; 99.42% |
| Correct backbone conformations | 79.23%; 75.41% |
| Bad bonds | 0/109,772; 0/109,772 |
| Bad angles | 5/171,185; 8/171,185 |
FSC, Fourier shell correlation; CC, correlation coefficient; RMS, root‐mean‐square.
a
Only across atoms in the model; compiled using Phenix (Afonine et al, 2013).
b
Compiled using MolProbity (Chen et al, 2010); p, percentile.
c
Clashscore is the number of serious steric overlaps (> 0.4 Å) per 1,000 atoms.