Innovation: A chemical toolkit for proteins - an expanded genetic code

Recently, a method to encode unnatural amino acids with diverse physicochemical and biological properties genetically in bacteria, yeast and mammalian cells was developed. Over 30 unnatural amino acids have been co-translationally incorporated into proteins with high fidelity and efficiency using a unique codon and corresponding transfer-RNA: aminoacyl-tRNA-synthetase pair. This provides a powerful tool for exploring protein structure and function in vitro and in vivo, and for generating proteins with new or enhanced properties.