Figure 5.

The nexin linker, IDL2, and IDL3. (a–i) Cross section and tilted views (yellow lines) and surface rendering, showing the circumferential nexin in all the doublets (a, d, and g), IDL2 from doublets 4, 5, and 9 (b, e, and h), and IDL3 from doublet 1 (c, f, and i). The green circles indicate the protofilaments in the adjacent B-tubule. The dotted red lines are drawn along the nexin, IDL2, and IDL3. The blue line and arrow in a indicate the cross section in the surface rendering (g–i) and the direction of view, respectively. The black arrowhead in g shows the protrusion above the radial spoke S3-like feature, which was identified as part of the nexin in our previous study (Bui et al., 2008), but it is now clear that it is not connecting to the nexin. Bars, 20 nm.