Extended Data Figure 3 |. Analogs of σ₂ receptor ligands and the effect of a structural water molecule.

a-c, Initial hits and selected analogs of σ₂ receptor ligands. Competition binding curves on the top panel, 2D drawings of compounds are on the bottom panel. Parent compound is indicated by gray background. Points shown as mean ± SEM from three technical replicates. a, Parent compound ZINC548355486 and its three potent analogues. b, Parent compound ZINC895657866 and its three potent analogues. c, Parent compound ZINC450573233 and its three potent analogues. d-f, The binding site of the σ₂ receptor contains a structural water. d, Water coordination at the binding site of the σ₂ receptor. Water molecule is depicted as a red sphere. Hydrogen bonds are indicated by black dashed lines. e, Saturation binding curve to measure the dissociation constant (K_d) of [³H]-DTG for the various mutants of σ₂ receptor meant to disrupt water coordination. Residues proximal to the structural water were chosen for mutation. Residues were mutated to the indicated amino acid. Points shown as mean ± SEM from three technical replicates. f, Competition binding measurement of affinity of Z1241145220 in various mutants of σ₂. Points shown as mean ± SEM from three technical replicates.