Synthesis and biological evaluation of new GABA-uptake inhibitors derived from proline and from pyrrolidine-2-acetic acid

Zhao, Xueqing; Hoesl, Cornelia E.; Hoefner, G.; Wanner, Klaus T.

doi:10.1016/j.ejmech.2004.11.004

Cited by 24 publications

(12 citation statements)

References 37 publications

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“…We chose well-known hydrophilic parent structures such as GABA (8), gu- S)-14 a), [34] and some of their lipophilic derivatives such as CI 966 (13 d), tiagabine ((R)-14 b), and SKF89976A (14 c), [34] which cover a broad range of affinities as well. Lipophilic compounds developed by us (compounds (S)-15 b to (2S,4R)-18 b, [35,36] see Figure 6) were also included in the study.…”

Section: Saturation Ms-binding Experiments With Native No 711mentioning

confidence: 99%

MS‐Binding Assays: Kinetic, Saturation, and Competitive Experiments Based on Quantitation of Bound Marker as Exemplified by the GABA Transporter mGAT1

2006

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A new kind of binding assay is described in which the amount of a nonlabeled marker bound to the target is quantified by LC-ESI-MS-MS. This new approach was successfully implemented with nonlabeled NO 711 as marker and the GABA transporter subtype mGAT1 as target. The native marker bound to the target was liberated from the receptor protein by methanol denaturation after filtration. A reliable and sensitive LC-ESI-MS-MS method for the quantitation of NO 711 was developed, and data from mass spectrometric detection were analyzed by nonlinear regression. Kinetic MS-binding experiments yielded values for k+1 and k-1, while in saturation MS-binding experiments, Kd and Bmax values were determined. In competitive MS-binding experiments, Ki values were obtained for various test compounds covering a broad range of affinities for mGAT1. All experiments were performed in 96-well plate format with a filter plate for the separation step which improved the efficiency and throughput of the procedure. The method was validated by classical radioligand-binding experiments with the labeled marker [3H2]NO 711 in parallel. The results obtained from MS-binding experiments were found to be in good agreement with the results of the radioligand-binding assays. The new kind of MS-binding assay presented herein is further adapted to the conventional radioligand-binding assay in that the amount of bound marker is securely quantified. This promises easy implementation in accordance with conventional binding assays without the major drawbacks that are inherent in radioligand or fluorescence binding assays. Therefore, MS-binding assays are a true alternative to classical radioligand-binding assays.

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Section: Saturation Ms-binding Experiments With Native No 711mentioning

confidence: 99%

MS‐Binding Assays: Kinetic, Saturation, and Competitive Experiments Based on Quantitation of Bound Marker as Exemplified by the GABA Transporter mGAT1

2006

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“…9 is further validated by our SAR and docking protocol, where all three classes A, B and C showed interactions between the protonated nitrogen atom and F294 and between the COOH group and G65. The effect of the COOH group, as well as the protonated nitrogen atom, on the inhibitory potency of hGAT1 modulators has been previously demonstrated by various authors (Zhao et al, 2005;Fülep et al, 2006;Kragler et al, 2008;Pizzi et al, 2011). Therefore, three orders of magnitude decrease in inhibitory potency of compound 37 as compared to compound 1 is may be due to absence of COOH group in its chemical scaffold.…”

Section: Manuscript To Be Reviewedmentioning

confidence: 86%

Peer Review #1 of "GRID-independent molecular descriptor analysis and molecular docking studies to mimic the binding hypothesis of γ-aminobutyric acid transporter 1 (GAT1) inhibitors (v0.1)"

2019

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Background: The γ-aminobutyric acid (GABA) transporter GAT1 is involved in GABA transport across the biological membrane in and out of the synaptic cleft. The efficiency of this Na + coupled GABA transport is regulated by an electrochemical gradient, which is directed inward under normal conditions. However, in certain pathophysiological situations, including strong depolarization or an imbalance in ion homeostasis, the GABA influx into the cytoplasm is increased by re-uptake transport mechanism. This mechanism may lead to extra removal of extracellular GABA which results in numerous neurological disorders such as epilepsy. Thus, small molecule inhibitors of GABA re-uptake may enhance GABA activity at the synaptic clefts. Methods: In the present study, various GRID Independent Molecular Descriptor (GRIND) models have been developed to shed light on the 3D structural features of hGAT1 inhibitors using nipecotic acid and N-diarylalkenyl piperidine analogs. Further, a binding hypothesis has been developed for the selected GAT1 antagonists by molecular docking inside the binding cavity of human GAT1 (hGAT1) homology model. Results: Our results indicate that two hydrogen bond acceptors, one hydrogen bond donor and one hydrophobic region at certain distances from each other play an important role in achieving high inhibitory potency against hGAT1. Our docking results elucidate the importance of the COOH group in hGAT1 antagonists by considering substitution of the COOH group with an isoxazol ring in compound 37, which subsequently leads to a three order of magnitude decrease in biological activity of 37 (IC 50 = 38 µM) as compared to compound 1 (IC 50 = 0.040 µM). Discussion: Our docking results are strengthened by the structure activity relationship (SAR) of the data series as well as by GRIND models, thus providing a significant structural basis for understanding the binding of antagonists, which may be useful for guiding the design of hGAT1 inhibitors.

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“…Database preparation. The initial dataset consisted of more than 400 compounds that were collected from the literature 4,8–9,11–16,18–19,26. The dataset was curated by removing data from racemic compounds and non comparable inhibition assays, resulting in a final 162 member dataset.…”

Section: Methodsmentioning

confidence: 99%

Classification of High‐Activity Tiagabine Analogs by Binary QSAR Modeling

Jurik

Reicherstorfer

Zdrazil

et al. 2013

Molecular Informatics

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Synthesis and biological evaluation of new GABA-uptake inhibitors derived from proline and from pyrrolidine-2-acetic acid

Cited by 24 publications

References 37 publications

MS‐Binding Assays: Kinetic, Saturation, and Competitive Experiments Based on Quantitation of Bound Marker as Exemplified by the GABA Transporter mGAT1

MS‐Binding Assays: Kinetic, Saturation, and Competitive Experiments Based on Quantitation of Bound Marker as Exemplified by the GABA Transporter mGAT1

Peer Review #1 of "GRID-independent molecular descriptor analysis and molecular docking studies to mimic the binding hypothesis of γ-aminobutyric acid transporter 1 (GAT1) inhibitors (v0.1)"

Classification of High‐Activity Tiagabine Analogs by Binary QSAR Modeling

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