Extended Data Figure 2. Resolution of the pre-fusion HKU1 S density map.
a, Local resolution within the EM density map. Local resolution was calculated using ResMap51 discretizing every 0.25 Å over a range from 2 × voxel size (2.62 Å) to 4 × voxel size (5.24 Å). Resolution significance criterion was set to 0.05. The resolution ranges from 3.74 Å in stable internal secondary structures to greater than 5.00 Å in flexible peripheral loops. b, Close-ups of secondary-structure densities. To the left is displayed the central α-helix of an S2 monomer and to the right is a β-sheet from the NTD domain in an S1 monomer.