Fig. 2.

PAC1 receptor 7TM interactions and water pathway formation. (A) Upper panels: hydrogen-bond network within the 7TM; lower panels: the salt bridge E344^ICL3-R185^ICL1 in ECD open and closed states. (B) Upper panel, water density cross section (upper panel) in side view of the receptor. Lower panel, top view of receptor core with TM2–TM6 and TM3–TM7 boundaries. The hydrophobic L192^2.53, L244^3.47, L358^6.45 and V396^7.53 residues are shown as spheres. An open water pathway is suggested in G1 and G2. Reprinted with permission from Liao et al. (2017) Sci Rep 7 (1):5427