Genetic incorporation of a metal-ion chelating amino acid into proteins as a biophysical probe

A metal-ion chelating amino acid ((8-hydroxyquinolin)-3-yl)alanine) is genetically encoded in Escherichia coli by an amber nonsense codon and corresponding orthogonal tRNA/aminoacyl-tRNA synthetase pair. The structure has showed a high occupancy of the heavy metal bound to the HQ-Ala residue and this method has facilitated the de novo design of metalloproteins with novel structures and functions, including fluorescence sensors.