Figure 1: Binding of peptide ligands to PTH1R incorporated in nanodiscs (PTH1R-ND).

Titrations of (A) PTH(1–34); (B) PTHrP(1–36); (C) PTH(1–34)E19AE22A; (D) PTH(1–14)PTHrP(15–36) and (E) PTHrP(1–14)PTH(15–34) with PTH1R in nanodiscs (PTH1R-ND) with (blue) and without (red) addition of 15 mM Ca²⁺ and nanodiscs containing no PTH1R (empty-ND) with (grey) and without (black) addition of 15 mM Ca²⁺. The peptide concentration was kept constant at 50 and 55 nM with and without addition of 15 mM Ca²⁺, respectively. (Buffer: 50 mM Tris-HCl pH 7.4, 150 mM NaCl, 3 mM MgCl₂, and 100 μM EDTA). Each data point in the titration curves is an average of more than three experiments and each experiment was performed using independent preparations of purified PTH1R-ND.