Species-scanning mutagenesis of the serotonin transporter reveals residues essential in selective, high-affinity recognition of antidepressants.

摘要: The serotonin transporter (SERT) is a high-affinity sodium/chloride-dependent neurotransmitter responsible for reuptake of from the extracellular space. SERT selective target several clinically important antidepressants. In cross-species analysis comparing human and bovine SERTs, kinetic parameters uptake were found to be similar, however, pharmacological profiles two transporters differ. Following transient expression in COS-1 cells, IC(50) values determined antidepressants psychostimulants. potencies citalopram, fluoxetine, paroxetine imipramine several-fold higher at hSERT compared with bSERT. No species selectivity was observed fluvoxamine, sertraline or psychostimulants cocaine, cocaine analogue beta-carbomethoxy-3beta-(4-iodophenyl)tropane, 3,4-methylenedioxymethamphetamine (MDMA). Analysis six hSERT/bSERT chimeras subsequent species-scanning mutagenesis each isoform revealed methionine-180, tyrosine-495, phenylalanine-513 increase citalopram methionine-180 confer fluoxetine imipramine. Results obtained by doing forward, human, mutations confirmed reverse mutations. Citalopram analogues used define roles reveal molecular interactions individual functional groups citalopram. We suggest that interacts heterocyclic nucleus stabilizes binding pocket steric blocker antidepressant recognition.