(A) A cluster of aromatic residues (F772.53, W2536.48 and Y2927.43) is located just below ZD7155, bridging the ligand binding pocket with a cluster of polar residues that includes several highly conserved in class A GPCR residues (N461.50, D742.50), along with N1113.35 and N2957.46 forming hydrogen bonds that hold helices III and VII together.
(B) Superposition of the AT1R structure with the high-resolution structure of δ-OR (PDB ID 4N6H) reveals a high structural conservation of the putative sodium-binding site.