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. 2020 Jul 23;5(14):e129070. doi: 10.1172/jci.insight.129070

Figure 9. Docking peptides into APLNR and PWR.

Figure 9

(A) ELA peptides were docked into the experimental APLNR structure. Colored spheres show the predicted position of the membrane. Two conserved disulfide bonds present in this family of receptors are shown in orange. The receptor (yellow) was shown to have 2 main grooves, 1 (red) and 2 (blue). Overall, the best predicted binding poses for the ELA peptide (blue tube) had the C-terminal region inserted in the canonical binding pocket region (site 1), while the N-terminal region seemed to fold back inside the groove 1 area. A disulfide bond in the ELA peptide is shown in magenta; this bond was not present in the apelin-like peptide cocrystallized with the APLNR receptor. ELA Arg residues that were mutated to serine in the present study to avoid cleavages by furin are shown in cyan. (B) View from the extracellular side. Proposed position of the ELA peptides at the surface of the receptor, top, ELA11, bottom, and mut ELA32. The receptor is shown as a solid surface and the peptide as a ribbon. Site 1 represents the canonical binding pocket in this family of receptors. The ELA11 peptide was essentially inserted into the receptor site 1; the longer ELA32 and mut ELA32 peptides protruded more outside the receptor and made several favorable interactions with residues of site 2 and folded back in the region of groove 1. One conserved disulfide bond in the receptor is shown (orange) to facilitate the reading of the figure. The mutated residues in ELA32 are shown in cyan. These residues point away from the receptor. (C) Schematic representation of APLNR with perpendicular p-polarized light (p-pol) to indicate vertical elongation of the receptor and parallel s-polarized light (s-pol) for horizontal elongation of the receptor on the cell membrane. (D–F) Binding curve for ELA11 (D), ELA32 (E), and mut ELA32 (F) interaction with APLNR in HEK-APLNR. D, E, and F are representative of 3 independent experiments, and graphs with mean ± SEM are shown in Supplemental Figure 7 (n = 3). Unpaired t tests were used to analyze the data. **P < 0.01, ***P < 0.001.