Detailed comparisons between oda1 and other mutants reveal the location of the AAA rings and the N-terminal tails of the eight dynein heavy chains. In each panel, the orientation is slightly different in order to show the rings and the tails, but the distal end is always at the right (the proximal side is at the left). Approximate positions and the model of one dynein heavy chain (right bottom; green, AAA ring; red, N-terminal tail [stem]; blue, coiled-coil stalk and microtubule-binding domain) are shown in A. The rings and the tails are shown by green rings and red lines, respectively. Two tails of the dynein f dimer merge (B), whereas pairs of heavy chains belonging to one dyad have a colinear architecture, with the N-terminal tails projecting from the distal sides of the rings without merging (C–F). Bar, 20 nm.