Figure 6.

Lipid and G-protein binding. (A) Probability histogram of volume overlap between a receptor-bound lipid and the C-terminal helix of a G_α protein based on postsimulation modeling, V_clash-lipid. Data are obtained from simulations of the G-protein-derived structure with (solid black line) zwitterionic, PC, and (dashed red line) anionic, PG, lipids. The dotted gray line represents the PC data after omitting the five simulations in which the bound lipid completely invaded the receptor’s binding pocket (Fig. S5). Distributions of V_clash vs. V_clash-lipid are provided in Fig. S10. (B and C) Two cytosolic depictions of the same representative snapshot from simulations in which an anionic lipid is bound at R3.50 and the values of V_clash and V_clash-lipid are similar to the mean values for lipid-bound states in these simulations (values for this snapshot are 0.2 and 0.05 nm³, respectively). To see this figure in color, go online.