PT - JOURNAL ARTICLE AU - Shiva Amiri AU - Masaru Shimomura AU - Ranjit Vijayan AU - Hisashi Nishiwaki AU - Miki Akamatsu AU - Kazuhiko Matsuda AU - Andrew K. Jones AU - Mark S. P. Sansom AU - Philip C. Biggin AU - David B. Sattelle TI - A Role for Leu118 of Loop E in Agonist Binding to the α7 Nicotinic Acetylcholine Receptor AID - 10.1124/mol.107.041590 DP - 2008 Jun 01 TA - Molecular Pharmacology PG - 1659--1667 VI - 73 IP - 6 4099 - http://molpharm.aspetjournals.org/content/73/6/1659.short 4100 - http://molpharm.aspetjournals.org/content/73/6/1659.full SO - Mol Pharmacol2008 Jun 01; 73 AB - Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels mediating fast cholinergic synaptic transmission in the brain and at neuromuscular junctions. We used the structure of the acetylcholine binding protein from Lymnaea stagnalis to model the chicken α7 agonist-binding domain. The initial models and a preliminary docking study suggested that position Leu118 may play an important role in determining agonist actions on α7. A prediction from these in silico studies, that L118E and L118D would retain binding to acetylcholine but L118K and L118R would not, was confirmed in electrophysiological studies on functional recombinant mutant receptors expressed in Xenopus laevis oocytes. The functional studies also demonstrated that residues at position 118 have a dramatic effect on the actions of imidacloprid (a partial agonist of wild-type α7 receptors) and its des-nitro derivative. Molecular dynamics simulations confirmed that Leu118 can strongly influence agonist binding and that the model was robust in terms of its prediction for acetylcholine binding. Together, the results indicate a role for Leu118 in influencing agonist actions on α7 nAChRs. The American Society for Pharmacology and Experimental Therapeutics