An Arginine Involved in GABA Binding and Unbinding But Not Gating of the GABAAReceptor

Abstract
GABAA receptor function can be conceptually divided into interactions between ligand and receptor (binding) and the opening and closing of the ligand-bound channel (gating). The relationship between binding, gating, and receptor structure remains unclear. Studies of mutations have identified many amino acid residues that contribute to the GABAbinding site. Most of these studies assayed changes in GABA dose–response curves, which are macroscopic measures that depend on the interplay of many processes and cannot resolve individual microscopic transitions. Understanding the microscopic basis of binding and gating is critical, because kinetic transition rates predict how receptors will behave at synapses. Furthermore, microscopic rates are directly related to the molecular interactions underlying receptor function.