Models of the C1a-e-c supercomplex. (A) The isosurface rendering shows the 3D structure of the averaged Chlamydomonas WT CA repeat viewed in longitudinal orientation. (B and C) A schematic drawing of the 32-nm repeat of the Chlamydomonas WT CA in longitudinal orientation (B; same orientation as in A) and cross-sectional view (C) to highlight the protein compositions of the C1a-e-c supercomplex within the ciliary CA; this includes densities containing the subunits PF16 and FAP92 (dark red), FAP76 (magenta), FAP81 (yellow), and FAP216 (green). Blue dots indicate the C-terminus of PF16 and N-terminus of FAP76 proteins. (D–H) Schematic drawings of the 32-nm CA repeat of various C1a-e-c mutants in cross-sectional view to show the observed structural defects.