Ligand interaction with the purified serotonin transporter in solution andat the air/water interface

The purified serotonin transporter (SERT) nas spread at the air/water inter face and the effects both of its surface density and of the temperature on its interfacial behavior were studied. The recorded isotherms evidenced the existence of a stable monolayer undergoing a lengthy rearrangement. SERT/l igand interactions appeared to be dependent on the nature of the studied mo lecules. Whereas an unrelated drug (chlorcyclizine) did not bind to the spr ead SERT, it interacted with its specific ligands, Compared to heterocyclic drugs, for which binding appeared to be concentration-dependent, a 'two-si te' mechanism was evidenced for pinoline and imipramine, (C) 2000 Federatio n of European Biochemical Societies.