New insights into the structure of the trace amine-associated receptor 2: Homology modelling studies exploring the binding mode of 3-iodothyronamine.

Recent studies have further investigated the trace amine-associated receptor type 2 (TAAR2) pharmacology, revealing its role not only at the olfactory sensory neurons but also at the immune system, being expressed in human leucocytes. In particular, the ability of this receptor to bind the unselective TAAR ligand 3-iodo-thyronamine (T1 AM) was elucidated, making in the meanwhile the discovery of selective compounds a urgent need to derive much more suitable tools for studying TAARs. In this context, we developed our work on TAAR2 applying a structure-based computational protocol, including TAAR2 homology modelling and T1 AM docking studies. The results were compared with those we previously obtained about TAAR1, in order to point out new insights guiding for selectivity between TAAR1 and TAAR2. The in silico strategy applied allowed us to provide for the first time thorough TAAR2 homology models, which are expected to be useful tools for a further design process of more selective TAAR ligands.