Titel
Exploring the molecular determinants for subtype-selectivity of 2-amino-1,4,5,6-tetrahydropyrimidine-5-carboxylic acid analogs as betaine/GABA transporter 1 (BGT1) substrate-inhibitors
Autor*in
Anas Al-Khawaja
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
Anne Stæhr Haugaard
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
... show all
Abstract
We have previously identified 2-amino-1,4,5,6-tetrahydropyrimidine-5-carboxylic acid (ATPCA) as the most potent substrate-inhibitor of the betaine/GABA transporter 1 (BGT1) (IC50 2.5 µM) reported to date. Herein, we characterize the binding mode of 20 novel analogs and propose the molecular determinants driving BGT1-selectivity. A series of N1-, exocyclic-N-, and C4-substituted analogs was synthesized and pharmacologically characterized in radioligand-based uptake assays at the four human GABA transporters (hGATs) recombinantly expressed in mammalian cells. Overall, the analogs retained subtype-selectivity for hBGT1, though with lower inhibitory activities (mid to high micromolar IC50 values) compared to ATPCA. Further characterization of five of these BGT1-active analogs in a fluorescence-based FMP assay revealed that the compounds are substrates for hBGT1, suggesting they interact with the orthosteric site of the transporter. In silico-guided mutagenesis experiments showed that the non-conserved residues Q299 and E52 in hBGT1 as well as the conformational flexibility of the compounds potentially contribute to the subtype-selectivity of ATPCA and its analogs. Overall, this study provides new insights into the molecular interactions governing the subtype-selectivity of BGT1 substrate-inhibitors. The findings may guide the rational design of BGT1-selective pharmacological tool compounds for future drug discovery.
Stichwort
PharmacodynamicsTransporters in the nervous system
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
phaidra.univie.ac.at/o:1248425
Erschienen in
Titel
Scientific Reports
Band
10
ISSN
2045-2322
Erscheinungsdatum
2020
Publication
Springer Science and Business Media LLC
Fördergeber
Austrian Science Fund (FWF) — F03502
Austrian Science Fund (FWF) — W1232
Erscheinungsdatum
2020
Zugänglichkeit
Rechte
Rechteangabe
© The Author(s) 2020
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