Patent ID: 8114629

Claim:
A cell comprising a translation system, wherein the translation system comprises: an orthogonal-tRNA (O-tRNA); an orthogonal aminoacyl-tRNA synthetase (O-RS); and, a para-substituted tyrosine; wherein the O-tRNA recognizes a first selector codon, and the O-RS preferentially aminoacylates an O-tRNA of SEQ ID NO: 21 with an efficiency of at least 50% of the efficiency of a polypeptide comprising an amino acid sequence of SEQ ID NO: 18 with p-acetyl-L-phenylalanine; wherein the O-RS is at least 90% identical to any of O-RSs of SEQ ID NOs: 18, 19 or 20; and comprises Ala or Leu at a position corresponding to position 32 or comprising Gly at a position corresponding to position 158 compared to wild type tyrosyl tRNA synthetase or comprises Ala or Leu at a position corresponding to position 32 and comprising Gly at a position corresponding to position 158 compared to wild type tyrosyl tRNA synthetase.