Fig. 6

Homology models and morphing. a Homology model of GluN1-1a (purple)/GluN2B (gray) ATD and LBD in active conformation. Subdomains of GluN2B ATD are colored in green (R1) and cyan (R2). Ifenprodil binding site is marked by red box. b Ifenprodil binding site in active conformation with vertical side chain orientation of GluN2B F176 (orange), H-bond acceptor GluN2B E236 (magenta) and α5 helix displaced in the direction towards ATD (yellow). c Ifenprodil binding site in deactivated conformation with horizontal side chain orientation for GluN2B F176 (orange), H-bond acceptor GluN2B E236 (magenta) and α5 helix displaced in the direction towards to LBD (yellow). d Ifenprodil binding site in ifenprodil-bound conformation with horizontal side chain orientation of GluN2B F176 (orange), H-bond acceptor GluN2B E236 (magenta) and docked ligand (R)-1 (green). The α5 helix (yellow) shows higher displacement in the direction towards the LBD than in the deactivated state. e Morphing results: Total RMSD for transition of active to deactivated (black) and active to ifenprodil-bound state (red) indicates increased conformational changes by ifenprodil binding. The morphing force required for the transition from active to deactivated state (gray) is larger than the force for transition of active to ifenprodil-bound state (orange) suggesting that ifenprodil binding induces deactivated receptor conformation