Site-specific incorporation of a fluorescent terphenyl unnatural amino acid.

The site-specific incorporation of unnatural amino acids into proteins has a wide range of biological implications. Of particular interest is the incorporation of fluorescent probes as a mechanism to track protein function, transport, and folding. Thus, the development of a novel system for the incorporation of new fluorescent unnatural amino acids has significant utility. Specifically, we have elucidated an aminoacyl-tRNA synthetase capable of recognizing a terphenyl UAA derivative, and charging a cognate tRNA with this amino acid for protein incorporation. Moreover, we have successfully incorporated this fluorescent UAA into GFP at several key residues, demonstrating a novel means to modulate fluorescence within the protein.