Table 1.
Cryo-EM data collection and image processing.
| Sample | 177 bp nucleosome | 177 bp chromatosome |
|---|---|---|
| Molecular mass (kDa) | 219 | 242 |
| Sample conc. (mg/ml) | 1.0 | ~ 0.58 |
| Sample support | Quantifoil R2/2 | Quantifoil R1.2/1.3 |
| Microscope | Tecnai Arctica | Titan Krios |
| Detector | Falcon III | K2 |
| Voltage (kV) | 200 | 300 |
| Pixel size/box size (Å) | 1.28/216 | 1.1/264 |
| No. movie frames | 7 | 40 |
| Mask diameter (Å) | 210 | 180 |
| Exposure time (s) | 2.1 | 15 |
| Electron dose (e−/Å2) | 21 | 80 |
| Micrographs recorded/used | 1310/1304 | 766/564 |
| Particles picked/used | 81,608/60,086 | 348,898/46,196 |
| Symmetry | C1 | C1 |
| Resolution (Å) | ~ 12.5 | ~ 4.5 |