TY - JOUR T1 - Photochemical Proteolysis of an Unstructured Linker of the GABA<sub>A</sub>R Extracellular Domain prevents GABA but not Pentobarbital Activation# JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.109.059832 SP - mol.109.059832 AU - Ariele P Hanek AU - Henry A. Lester AU - Dennis A. Dougherty Y1 - 2010/01/01 UR - http://molpharm.aspetjournals.org/content/early/2010/04/02/mol.109.059832.abstract N2 - The γ-aminobutyric type A receptor (GABAAR) is the major inhibitory receptor in the mammalian CNS and the target of numerous pharmaceuticals. The α subunit of these pentameric Cys-loop neurotransmitter-gated ion channels contributes to the binding of both GABA and allosteric modulators such as the benzodiazepines, suggesting a role for this subunit in the conformational changes associated with activation of the receptor. Herein we use the nonsense suppression methodology to incorporate a photoactivatable unnatural amino acid, and photochemically cleave the backbone of the α subunit of the α1β2 GABAAR in a linker region that is thought to span the subunit. Proteolytic cleavage impairs GABA but not pentobarbital activation, strongly suggesting that conformational changes involving this linker region are critical to the GABA activation pathway.The American Society for Pharmacology and Experimental Therapeutics ER -