Affiliation: Laboratory of Christopher Ahern, Department of Molecular Physiology and Biophysics, University of Iowa 

Abstract: Ion channels play central roles in biology and human health by catalyzing the transmembrane flow of electrical charge. Recent advances with single particle cryo-EM have made significant advances in depicting the remarkable and diverse structures of these proteins while many questions remain unanswered regarding their mechanisms of function and pharmacology. 

These proteins are ideal targets for a method that is broadly termed genetic code expansion (GCE), whereby new types of synthetic amino acids can be encoded within an expressed protein. Ion channels are an ideal test-case because it is feasible to measure ion channel activity from miniscule amounts of protein and to analyze the resulting data via rigorous, established biophysical methods. 

In an ideal scenario, the encoding of a synthetic, noncanonical amino acid via GCE allows the experimenter to ask questions inaccessible to traditional methods. For this reason, GCE has been successfully applied to a variety of ligand- and voltage-gated channels wherein extensive structural, functional, and pharmacological data exist. 

I will provide an update of recent progress from my lab in the application of GCE methods as applied to ion channels. Data vignettes will be presented on the use of main-chain mutagenesis via the encoding of alpha-hydroxy acids, as well as fluoro-aromatics to study ligand, drug and protein-protein interactions, and caged-serine to study phospho-regulation. These examples will highlight the promise and challenges of GCE as applied to ion channels with a path towards future advances.