Fig. 7. Diameter variation of the dynamin A ring complex in the presence of GppNHp. (A) Four individual images as picked from the micrograph are shown. Note the varying diameters of the displayed ring-like structures. (B) Nine hundred and fifty-four aligned top views of the dynamin A ring complex in the presence of GppNHp are grouped into eight classes by multivariate statistical analysis and classification to visualize the diameter variations. Note that a segment in which inner and outer rings are blurred increases as the diameter decreases. (C) Averaged image of 184 top views of ring complexes with large diameter (Figure 7B, class 1). The inner and outer rings have averaged diameters of 18 and 26 nm, respectively. An 11-fold rotational symmetry was detected by eigenvector analysis. (D) Averaged image of 188 top views of ring complexes with small diameter (Figure 7B, classes 6–8), presumably short, constricted helices (see text). The inner and outer rings have averaged diameters of 15 and 21 nm, respectively. No rotational symmetry was detected by eigenvector analysis, and structural details such as the spike-like structures are not visible. A small segment remains blurry (arrowhead). The scale bars in (A)–(D) all represent 10 nm.