Figure 3.

Conformational variability in the apical domain

(A) Eight subunit reconstructions show variable apical domain positions. The position of helix I in class 1 is indicated by dotted lines to help compare the classes.

(B) Overlay of flexibly fitted models for classes 3, 8, and 10 in purple, gray, and light red.

(C) Plot of measured equatorial/apical domain distances for all eight classes. Each class is represented by a gray point; classes 3, 8 and 10 are labeled. Points approximately lie on the diagonal, showing that the entire apical domain rotates upward. The background color is an estimate of the probability to find a subunit in a certain conformation, taking the particle number in each class into account. PDF stands for probability density function.