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Structural and dynamic mechanisms of GABAA receptor modulators with opposing activities

Journal Article · · Nature Communications
 [1];  [2];  [3];  [4];  [5];  [3]
  1. University of Texas Southwestern Medical Center, Dallas, TX (United States); OSTI
  2. KTH Royal Institute of Technology, Solna (Sweden)
  3. University of Texas Southwestern Medical Center, Dallas, TX (United States)
  4. Stockholm University (Sweden)
  5. KTH Royal Institute of Technology, Solna (Sweden); Stockholm University (Sweden)
γ-Aminobutyric acid type A (GABAA) receptors are pentameric ligand-gated ion channels abundant in the central nervous system and are prolific drug targets for treating anxiety, sleep disorders and epilepsy. Diverse small molecules exert a spectrum of effects on γ-aminobutyric acid type A (GABAA) receptors by acting at the classical benzodiazepine site. They can potentiate the response to GABA, attenuate channel activity, or counteract modulation by other ligands. Structural mechanisms underlying the actions of these drugs are not fully understood. Here we present two high-resolution structures of GABAA receptors in complex with zolpidem, a positive allosteric modulator and heavily prescribed hypnotic, and DMCM, a negative allosteric modulator with convulsant and anxiogenic properties. These two drugs share the extracellular benzodiazepine site at the α/γ subunit interface and two transmembrane sites at β/α interfaces. Structural analyses reveal a basis for the subtype selectivity of zolpidem that underlies its clinical success. Molecular dynamics simulations provide insight into how DMCM switches from a negative to a positive modulator as a function of binding site occupancy. Together, these findings expand our understanding of how GABAA receptor allosteric modulators acting through a common site can have diverging activities.
Research Organization:
University of Texas Southwestern Medical Center, Dallas, TX (United States)
Sponsoring Organization:
Marie Sklodowska-Curie; National Institutes of Health (NIH); Swedish Research Council; Swedish e-Science Research Center; USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER); Welch Foundation
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
1903929
Journal Information:
Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 13; ISSN 2041-1723
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English

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