Fig 4. Stability of interactions between PUT and CAD and human TAAR6 and TAAR8.

Time evolution (x-axis) of intermolecular distances (y-axis) between Asp_3.32/5.43 (-COO^-) and PUT/CAD (-NH3⁺) in 1.0 μs unbiased MD simulations. Each plot corresponds to one of the eight simulated ligand-receptor molecular complexes: hTAAR6_active-like/PUT (A), hTAAR6_active-like/CAD (B), hTAAR8_active-like/PUT (C), hTAAR8_active-like/CAD (D), hTAAR6_{inactive-like}/PUT (E), hTAAR6_{inactive-like}/CAD (F), hTAAR8_{inactive-like}/PUT (G), hTAAR8_{inactive-like}/CAD (H). Continuous and dotted lines correspond to distances between N1 and N2 atoms of the ligands with Asp_3.32 (red) and Asp_5.43 (blue) carboxyl groups, respectively. Black arrows at the bottom indicate the flip-transitions (180° rotation) of PUT and CAD in the binding pocket of the inactive-like models.