Biosynthesis of Proteins Incorporating a Versatile Set of Phenylalanine Analogues

Unnatural amino acids with useful chemical functionality can replace phenylalanine in bacterial proteins. Coexpression of a promiscuous phenylalanine-tRNA synthetase mutant enables the synthesis of target proteins bearing iodophenyl, cyanophenyl, ethynylphenyl, azidophenyl, and pyridyl groups (see general structures). Proteins incorporating the analogues have a range of potential applications, including Pd-mediated conjugation (R=CCH), photoaffinity labeling (R=N_3), X-ray phasing (R=I), and novel metal coordination (R=pyridyl).