NICOTINIC RECEPTOR-BINDING SITE PROBED WITH UNNATURAL AMINO-ACID-INCORPORATION IN INTACT-CELLS

The nonsense codon suppression method for unnatural amino acid incorpo ration has been applied to intact Cells and combined with electrophysi ological analysis to probe structure-function relations in the nicotin ic acetylcholine receptor, Functional receptors were expressed in Xeno pus oocytes when tyrosine and phenylalanine derivatives were incorpora ted at positions 93, 190, and 198 in the binding site of the a subunit , Subtle changes in the structure of an individual side chain produced readily detectable changes in the function of this large channel prot ein, At each position, distinct features of side chain structure domin ated the dose-response relation, probably by governing the agonist-rec eptor binding.