Genetic code expansion is a powerful tool to extend the chemical diversity of proteins. Since its introduction more than 25 years ago, this method has been widely applied to modify proteins with over 100 non-canonical amino acids to study protein structure and impart new function.
This talk will present our implementation of genetic code expansion, and how aminoacyl-tRNA synthetases with high fidelity are identified in a large library of mutants to afford site-specific incorporation of a non-canonical amino acid in response to an amber stop codon. I will highlight applications of genetically encoded non-canonical amino acids for bio-orthogonal protein functionalization and as molecular probes to study binding affinities, dynamics and structures of proteins. Finally, I will show unexpected results and discuss their implications.