Changes in postsynaptic density protein-95, Drosophila disc large tumor suppressor, and zonula occludens-1 (PDZ1–3) of postsynaptic density protein-95 (PSD-95) produced by binding of peptides NR2A-c20 or NR2B-c20 in the absence or presence of isoflurane. (A and B) The structure of PDZ1–3 of PSD-95 showing residues with diminished (left) and enhanced (right) nuclear magnetic resonance peak intensities after binding to NR2A-c20 (A) or NR2B-c20 (B). Color codes: blue = changed only by NR2A-c20 binding; red = changed only by NR2B-c20 binding; green = changed in both cases of binding. The same color codes are applied to all figures here. (C) The combined ¹H and ¹⁵N chemical shift changes in PDZ1–3 of PSD-95 upon NR2A-c20 (blue) or NR2B-c20 (red) binding. (D) The combined ¹H and ¹⁵N chemical shift changes induced by isoflurane in PDZ1–3 of PSD-95 bound with NR2A-c20 (red) or NR2B-c20 (green). (E–G) The structure of PDZ1–3 of PSD-95 showing isoflurane-disturbed residues (Δδ ≥ 0.04 ppm) upon binding of NR2A-c20 (E), NR2B-c20 (F), or no peptide present (G). Concentrations used are 100 μM for PDZ1–3 of PSD-95, 310 μM for peptides, and 3 mM for isoflurane.