Patent ID: 8192952

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), wherein said first O-RS comprises the amino acid sequence set forth in SEQ ID NO: 4, or a conservative variant thereof, which conservative variant is at least 90% identical to SEQ ID NO: 4 and comprises a Glu at amino acid position 32; a Gly or Ala at amino acid position 67; a Gly at amino acid position 70; and a Gly at amino acid position 158; 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.