Schematic model of human vasopressin receptor (V₂R) binding with oxytocin (OT), oxytocin extended form (OT-GKR), and arginine vasopressin (AVP).

(A) The front upright view position (side view) of the receptor structure with OT. (B) The top intracellular view (i.e. rotation by 90^o out of plane) of OT-GKR inside the OTR binding site.(C) Conformational view of AVP, OT-GKR, and OT and (D) schematic model of human vasopressin V₂R binding with AVP, OT-GKR and OT. The amino acid residues in black circles have been proposed as OT docking sites, the red bars represent docking sites of OT-GKR and the green bars represent docking sites of AVP. Amino acid residues are identified by a 1-letter code in Table 1.