Fig. 3: Binding mode of peptide antagonist CYN 154806.

a Sequence alignment of SST-14, CYN 154806, octreotide and peptide 3. Key pharmacophore (F7–W8–K9–T10) is indicated by red dotted box; disulfide bonds are indicated by yellow lines. Sequence numbers are labeled based on SST-14. b Comparison of the binding modes of CYN 154806 and SST-14 in SSTR2. CYN 154806 is shown as yellow sticks and SST-14 is shown as cartoon and sticks in orange. Disulfide bonds are shown as yellow sticks. Conformational changes are indicated by red arrows. c Interactions between the d-W8–K9 of CYN 154806 and SSTR2. Residues involved in ligand binding are shown as green sticks. Polar interactions are indicated by red dash lines. d Interactions between the outside of d-W8–K9 of CYN 154806 and SSTR2. e Ligand binding of WT SSTR2 and SSTR2 mutants in the residues that interact with CYN 154806 in competition with ¹²⁵I-SST-14. All data are shown as means ± SEM from at least three independent experiments performed in triplicate. Detailed statistical evaluation is shown in Supplementary information, Table S4.