Fig. 6: Mechanism of Immethridine selectivity for H3R.
From: Structural basis of ligand recognition and activation of the histamine receptor family
a Representative concentration-dependent response curves of H3R and its L4017.42Q mutant, and H4R and its Q3477.42L mutant, in response to Immethridine and Immepip using the Gαi-Gγ dissociation assay. The pEC50 and Emax values are provided in Supplementary Table 4. Data from three independent experiments are presented as the mean ± SEM (n = 3). b 2D depiction of contacts between H3R with the ligand Immethridine (left panel) and H4R with the ligand Immepip (right panel). Hydrogen bonds are indicated by red dotted lines. The piperidine ring is highlighted in red shade, while the pyridine ring is highlighted in green shade. c 3D representation showing detailed interaction of immethridine/immepip with the unique L/Q7.42 of H3R (left panel) and H4R (right panel). Hydrogen bonds are depicted as red dashed lines. d Barcode representation illustrating potential interaction patterns in the ligand pockets of H3R (immethridine-bound) and H4R (immepip-bound). Common residues within histamine receptors interacting with ligands are depicted as gray circles, with the unique residue L/Q7.42 highlighted in green for H3R and orange for H4R.
