Fig. 4. Insights into ligand binding.

a A schematic summary of histamine, Clobenpropit, VUF6884, and Clozapine/receptor interactions. Green solid circle, hydrophobic interaction; purple solid circle, polar interaction; white emptied circle, no interaction. b Radar chart for affinities of ligands the four agonists to the wild-type and mutant H4R receptors, as measured by [3H]JNJ7777120 binding. c BRET-based Gi-protein activation assay of the wild-type and E182 H₄R mutants. Data are presented as mean values ± SEM.; n = 6 independent experiments for WT, n = 7 independent experiments for E182A and n = 3 for E183Q. Source data are provided as a Source Data file. d A structural analysis of the interaction of clobenpropit with E182 and its mutants.