Figure 1.

Structure of H₁R in complex with the antagonist doxepin. H₁R ribbon representation indicating the position of doxepin (green sticks) and phosphate (red/orange sticks) in the crystal structure. The encircled residue D73^2.50 marks the approximate location at which a Na${}^{+}$ ion was found in other GCPRs. The four other residues shown in stick presentation represent the sites of mutation that were investigated in the present study.The membrane is schematically depicted as a black line. Coordinates from PDB entry 3RZE [15].