FIGURE 4:

Structure of radial spokes from WT (A, B) (EMD-2131; Bui et al., 2012), ndk5 mutant (C, D), and pf24 mutant (E, F; Pigino et al., 2011) Chlamydomonas. Density maps were obtained by averaging subtomograms involving the 96-nm periodic unit from cryo-electron tomography and shown as transverse (A, C, E) and longitudinal (B, D, F) sections. Red arrows indicate corresponding positions of the RS neck. The density at the position of the spokehead components, RSP1, 4, 6, 9, and 10, are missing in averaged cryo-electron tomograms from the ndk5 strain (C, D) similar to the pf24 headless mutant (E, F). Scale bar: 24 nm.