Extended Data Table 1.
Cryo-EM structure determination and model statistics for full-length (FL) and pronase-treated (PT) filaments
| Data Collection | FL PHF | PT PHF | FL SF | PT SF |
|---|---|---|---|---|
| Magnification | ×105,000 | ×105,000 | ×105,000 | ×105,000 |
| Defocus range (μm) | −1.0 to −3.0 | −1.0 to −3.0 | −1.0 to −3.0 | −1.0 to −3.0 |
| Voltage (kV) | 300 | 300 | 300 | 300 |
| Microscope | Krios | Krios | Krios | Krios |
| Camera | K2 Summit | K2 Summit | K2 Summit | K2 Summit |
| Frame exposure time (s) | 0.2 | 0.8 | 0.2 | 0.8 |
| # movie frames | 50 | 20 | 50 | 20 |
| Total electron dose (e−/Å−2) | 60 | 55 | 60 | 55 |
| Pixel size (Å) | 1.04 | 1.15 | 1.04 | 1.15 |
|
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| Reconstruction | FL PHF | PT PHF | FL SF | PT SF |
|
| ||||
| Box size (pixel) | 270 | 270 | 270 | 270 |
| Inter-box distance (Å) | 28 | 28 | 28 | 28 |
| # segments extracted | 214,757 | 66,585 | 84,701 | 9,273 |
| # segments after Class2D | 214,262 | 61,321 | 84,089 | 8,891 |
| # segments after Class3D | 23,086 | 20,778 | 24,689 | 8,627 |
| Resolution (Å) | 3.4 | 3.5 | 3.4 | 4.9 |
| Map sharpening B-factor (Å2) | −105 | −106 | −114 | −79 |
| Helical rise (Å) | 2.36 | 2.36 | 4.74 | 4.78 |
| Helical twist (°) | 179.4 | 179.4 | −1.05 | −1.01 |
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| Atomic model | FL PHF | PT PHF | FL SF | PT SF |
|
| ||||
| # unique non-hydrogen atoms | 555 | 555 | 555 | – |
| R.m.s.d. bonds (Å) | 0.01 | 0.01 | 0.01 | – |
| R.m.s.d. angles (°) | 1.04 | 0.82 | 0.81 | – |
| Molprobity clashscore, all atoms | 5.13 | 7.42 | 5.78 | – |
| Molprobity score | 2.03 | 1.88 | 1.91 | – |
| Favored rotamers (%) | 98.44 | 96.88 | 96.85 | – |
| Ramachandran outliers (%) | 0.00 | 0.00 | 0.00 | – |
| Ramachandran favoured (%) | 78.4 | 92.49 | 88.11 | – |
| Cβ deviations > 0.25 Å (%) | 0.00 | 0.00 | 0.00 | – |
| Bad bonds (%) | 0.00 | 0.00 | 0.00 | – |
| Bad angles (%) | 0.00 | 0.00 | 0.00 | – |
| Average FSC model-vs-map | 0.80 | 0.80 | 0.75 | – |