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
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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. / Kickinger, Stefanie; Al-Khawaja, Anas; Haugaard, Anne Staehr; Lie, Maria E. K.; Bavo, Francesco; Loeffler, Rebekka; Damgaard, Maria; Ecker, Gerhard F.; Frolund, Bente; Wellendorph, Petrine.
I: Scientific Reports, Bind 10, Nr. 1, 12992, 2020.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - 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
AU - Kickinger, Stefanie
AU - Al-Khawaja, Anas
AU - Haugaard, Anne Staehr
AU - Lie, Maria E. K.
AU - Bavo, Francesco
AU - Loeffler, Rebekka
AU - Damgaard, Maria
AU - Ecker, Gerhard F.
AU - Frolund, Bente
AU - Wellendorph, Petrine
PY - 2020
Y1 - 2020
N2 - 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 mu M) reported to date. Herein, we characterize the binding mode of 20 novel analogs and propose the molecular determinants driving BGT1-selectivity. A series of N-1-, exocyclic-N-, and C-4-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.
AB - 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 mu M) reported to date. Herein, we characterize the binding mode of 20 novel analogs and propose the molecular determinants driving BGT1-selectivity. A series of N-1-, exocyclic-N-, and C-4-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.
KW - GABA TRANSPORTER
KW - PHARMACOLOGICAL CHARACTERIZATION
KW - CEREBRAL-CORTEX
KW - HIGH-AFFINITY
KW - ANTICONVULSANT ACTION
KW - BINDING-SITE
KW - LOCALIZATION
KW - TARGETS
KW - IDENTIFICATION
KW - DIVERSITY
U2 - 10.1038/s41598-020-69908-w
DO - 10.1038/s41598-020-69908-w
M3 - Journal article
C2 - 32747622
VL - 10
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 12992
ER -
ID: 248814878