FIGURE 6.

A, space-filling representation of the assembly of the C1r/C1s CUB₁-EGF-CUB₂ interaction domains as proposed to occur in the C1 complex (17) (top view). C1r and C1s are shown in yellow and gray, respectively. The color coding used is the same as stated in the legend to Fig. 3. Residues interacting with C1q are colored green. The six collagen triple helices of C1q are shown as magenta spheres. B and C, side and bottom views of the whole C1 complex highlighting the positioning of the C1s SP domains with respect to the remainder of the complex. Both C1r monomers are in yellow, whereas C1s molecules are shown in cyan and magenta. The color coding used for lysine residues is the same as stated in the legend to Fig. 3.