Extended Data Table 1.
Cryo-EM data collection, processing, and model refinement statistics of the apo L-21 and holo L-16 ScaI ribozyme.
| Cryo-EM data collection and processing | The apo L-21 ScaI ribozyme | The holo L-16 ScaI ribozyme |
|---|---|---|
| Microscope | Titan Krios | Titan Krios |
| Voltage (kV) | 300 | 300 |
| GIF Quantum energy filter slit width (eV) | 20 | 15 |
| Detector | Gatan K2 | Gatan K3 |
| Nominal Magnification | 215,000 × | 105,000 × |
| Pixel size (Å) | 0.65 | 0.86 |
| Symmetry imposed | C1 | C1 |
| Defocus range (μm) | −0.3 – −1.5 | −0.8 – −2.0 |
| Electron exposure (e−/Å2) | 75 | 50 |
| Micrographs (acquired/used) | 7,577/7,469 | 5,559/5,374 |
| Number of extracted particles | 1,658,961 | 854,763 |
| Number of particles after 2D classifications | 1,559,933 | 525,373 |
| Number of particles going to 3D refinement | 415,918 | 230,386 |
| Map resolution at 0.143 FSC criterion (Å) | 3.1 | 3.06 |
| Local resolution range (Å) | 3.0–4.7 | 2.9–5.6 |
| Sharpening B-factor (Å2) | −14 | −30 |
| Model refinement | ||
| Atoms | 8,306 | 8,698 |
| Residues | 387 | 406 |
| CCmask | 0.79 | 0.82 |
| ResolutionFSC map vs. model @ 0.5 (Å) | 3.2 | 3.0 |
| r.m.s. deviations | ||
| Bond lengths (Å) | 0.003 | 0.002 |
| Bond angles (°) | 0.547 | 0.523 |
| Clash score | 2.65 | 1.91 |
| MolProbity score | 2.20 | 2.10 |