Relative positioning of classical benzodiazepines to the γ2-subunit of GABAA receptors

Simon J. Middendorp, Evelyn Hurni, Matthias Schönberger, Marco Stein, Michael Pangerl, Dirk Trauner, Erwin Sigel

Research output: Contribution to journalArticle

Abstract

GABAA receptors are the major inhibitory neurotransmitter receptors in the brain. Benzodiazepine exert their action via a high affinity-binding site at the α/γ subunit interface on some of these receptors. Diazepam has sedative, hypnotic, anxiolytic, muscle relaxant, and anticonvulsant effects. It acts by potentiating the current evoked by the agonist GABA. Understanding specific interaction of benzodiazepines in the binding pocket of different GABAA receptor isoforms might help to separate these divergent effects. As a first step, we characterized the interaction between diazepam and the major GABAA receptor isoform α1β2γ2. We mutated several amino acid residues on the γ2-subunit assumed to be located near or in the benzodiazepine binding pocket individually to cysteine and studied the interaction with three ligands that are modified with a cysteine-reactive isothiocyanate group (-NCS). When the reactive NCS group is in apposition to the cysteine residue this leads to a covalent reaction. In this way, three amino acid residues, γ2Tyr58, γ 2Asn60, and γ2Val190 were located relative to classical benzodiazepines in their binding pocket on GABAA receptors.

Original languageEnglish (US)
Pages (from-to)1846-1853
Number of pages8
JournalACS Chemical Biology
Volume9
Issue number8
DOIs
StatePublished - Aug 15 2014

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine

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