Extended Data Table 1.
Cryo-EM data collection, refinement and validation statistics.
| Ubc4 complex (EMD-0360) (PDB 6N7P) |
Act1 complex (EMD-0361) (PDB 6N7R) |
|
|---|---|---|
| Data collection and processing | ||
| Magnification | 105,000 | 105,000 |
| Voltage (kV) | 300 | 300 |
| Electron exposure (e−/Å2) | 34.6 | 29.4 |
| Defocus range (μm) | −1.5 ~ −3.0 | −1.5 ~ −3.0 |
| Pixel size (Å) | 1.36 | 1.36 |
| Symmetry imposed | C1 | C1 |
| Initial particle images (no.) | 1,924,710 | 3,589,121 |
| Final particle images (no.) | 124,825 | 270,587 |
| Map resolution (Å) | 3.6 | 3.2 |
| FSC threshold | 0.143 | 0.143 |
| Map resolution range (Å) | ||
| Core | 3.0-4.5 | 3.0-4.5 |
| Pre-mRNA helix | --- | 3.0-6.5 |
| Prp40 | 15-20 | --- |
| Nam8 | 15-20 | --- |
| NCBPs | 15-25 | --- |
| U1 snRNA | 6-15 | 6-15 |
| Refinement | ||
| Initial model used (PDB code) | n/a | n/a |
| Model resolution (Å) | 4.6 | 4.3 |
| FSC threshold | 0.5 | 0.5 |
| Model resolution range (Å) | 4.6 | 4.3 |
| Map sharpening B factor (Å2) | −147.1 | −94.0 |
| Model composition | ||
| Non-hydrogen atoms | 41487 | 35784 |
| Protein residues | 4839 | 3568 |
| Ligands | 3 | 1 |
| B factors (Å2) | ||
| Protein | 57.5 | 59.9 |
| Ligand | 85.3 | 79.6 |
| R.m.s. deviations | ||
| Bond lengths (Å) | 0.01 | 0.02 |
| Bond angles (°) | 1.35 | 1.50 |
| Validation | ||
| MolProbity score | 1.89 | 1.99 |
| Clashscore | 5.09 | 5.07 |
| Poor rotamers (%) | 1.50 | 2.72 |
| Ramachandran plot | ||
| Favored (%) | 92.05 | 94.21 |
| Allowed (%) | 7.35 | 5.37 |
| Disallowed (%) | 0.60 | 0.42 |