FIGURE 5.

Schematic drawings showing the size and shape differences of the protein complexes and the preferential curvature arising from pairs of contacts. RC-LH1s (red) and LH2s (green) are essentially cylinders of 12 nm and 6 nm of diameter, respectively. Only LH2s have membrane-curving properties, as discussed in the text. A truncated cone indicates this. LH2-LH2 contacts acquire a positive spontaneous curvature c_{0 LH2-LH2} due to the coupling of their truncated-cone shapes (upper row). Cylindrically shaped RC-LH1s preferably flatten the membrane with c_{0 RC-LH1-RC-LH1} = 0 (second row). By geometry, ideally matching RC-LH1s and LH2s generate a curvature c_{0 RC-LH1-LH2}/c_{0 LH2-LH2} = 1/3 (third row). LH2-induced deformation of the more flexible RC-LH1, indicated by an angle mark, increases the former parameter up to 1 (last row).