Figure 3. Application of the statistical video processing procedure to an 80S ribosome data set.
(A) Gold-standard FSC curves for class 1 (red) and class 2 (green). (B) Slices through the reconstructions of class 1 (left) and class 2 (right). The fuzzy appearance for the density of the 40S subunits (green and red lines) is an indication of unresolved structural heterogeneity. (C–G) Densities for the 60S subunit of class 1 showing a protein loop interacting with a flipped-out RNA base (C), a short stretch of an RNA helix (D), a β-strand (E), a β-sheet (F), and an α-helix (G). (H–I) Density for the 40S subunit of class 1 showing a well-resolved α-helix (H) and a poorly-resolved one (I). The density map of class 1 was sharpened with a B-factor of −160 Å2. (J) FSC curves between the map of class 1 and the rigid-body fitted atomic models of the entire 80S particle, and for the 40S and 60S subunits separately. (K) As in J, but for class 2.