5ojm
From Proteopedia
Structure of a chimaeric beta3-alpha5 GABAA receptor in complex with nanobody Nb25
Structural highlights
DiseaseGBRB3_HUMAN Autism;Childhood absence epilepsy. Disease susceptibility is associated with variations affecting the gene represented in this entry. FunctionGBRB3_HUMAN GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.GBRA5_HUMAN GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel. Publication Abstract from PubMedType A gamma-aminobutyric acid receptors (GABAARs) are the principal mediators of inhibitory neurotransmission in the human brain. Endogenous neurosteroids interact with GABAARs to regulate acute and chronic anxiety and are potent sedative, analgesic, anticonvulsant and anesthetic agents. Their mode of binding and mechanism of receptor potentiation, however, remain unknown. Here we report crystal structures of a chimeric GABAAR construct in apo and pregnanolone-bound states. The neurosteroid-binding site is mechanically coupled to the helices lining the ion channel pore and modulates the desensitization-gate conformation. We demonstrate that the equivalent site is responsible for physiological, heteromeric GABAAR potentiation and explain the contrasting modulatory properties of 3a versus 3b neurosteroid epimers. These results illustrate how peripheral lipid ligands can regulate the desensitization gate of GABAARs, a process of broad relevance to pentameric ligand-gated ion channels. Structural basis for GABAA receptor potentiation by neurosteroids.,Miller PS, Scott S, Masiulis S, De Colibus L, Pardon E, Steyaert J, Aricescu AR Nat Struct Mol Biol. 2017 Oct 9. doi: 10.1038/nsmb.3484. PMID:28991263[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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