Patent ID: 7807411

Claim:
A translation system comprising: (a) a first unnatural amino acid that is an L-(7-hydroxycoumarin-4-yl)ethylglycine unnatural amino acid; (b) a first orthogonal aminoacyl-tRNA synthetase (O-RS); and (c) a first orthogonal tRNA (O-tRNA); wherein said first O-RS preferentially aminoacylates said first O-tRNA with said first unnatural amino acid and wherein said first O-RS comprises the amino acid sequence set forth in SEQ ID NO: 4, or conservative variants thereof comprising at least 95% sequence identity to SEQ ID NO: 4 with the proviso that positions 32, 65, 67, 70 108, 109, 158 and 162 of SEQ ID NO: 4 are conserved.