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Diazepam-bound GABAA receptor models identify new benzodiazepine binding-site ligands

2012; Nature Portfolio; Volume: 8; Issue: 5 Linguagem: Inglês

10.1038/nchembio.917

1552-4469

Lars Richter, Chris de Graaf, Werner Sieghart, Zdravko Varagić, Martina Mörzinger, Iwan J. P. de Esch, Gerhard F. Ecker, Margot Ernst,

Pharmacological Receptor Mechanisms and Effects

Diazepam-bound GABAA receptor models used for virtual screening lead to discovery of new ligands that modulate GABAA receptors expressed in Xenopus laevis oocytes via their benzodiazepine binding site. Benzodiazepines exert their anxiolytic, anticonvulsant, muscle-relaxant and sedative-hypnotic properties by allosterically enhancing the action of GABA at GABAA receptors via their benzodiazepine-binding site. Although these drugs have been used clinically since 1960, the molecular basis of this interaction is still not known. By using multiple homology models and an unbiased docking protocol, we identified a binding hypothesis for the diazepam-bound structure of the benzodiazepine site, which was confirmed by experimental evidence. Moreover, two independent virtual screening approaches based on this structure identified known benzodiazepine-site ligands from different structural classes and predicted potential new ligands for this site. Receptor-binding assays and electrophysiological studies on recombinant receptors confirmed these predictions and thus identified new chemotypes for the benzodiazepine-binding site. Our results support the validity of the diazepam-bound structure of the benzodiazepine-binding pocket, demonstrate its suitability for drug discovery and pave the way for structure-based drug design.