Patent ID: 8642291

Claim:
A method for producing a protein into which a tyrosine analogue has been incorporated, wherein the method comprises: (a) introducing a gene encoding a mutant tRNA synthetase (mtRS) derived from a yeast cell capable of binding to a tyrosine analogue, wherein said mtRS has a higher specificity for the tyrosine analogue compared to specificity for tyrosine; wherein the yeast host cell has a knockout of the endogenous tyrosyl-tRNA synthetase and tyrosine tRNA genes; b) introducing a suppressor tRNA derived from the tyrosyl-tRNA gene of a yeast; c) introducing an E. coli tyrosyl-tRNA synthetase and an E. coli tRNA genes specific for tyrosine into the yeast host cell; and d) introducing a target gene having at least one suppressor codon at a specific site; wherein the yeast host cell is cultured in a medium thereby expressing the target protein into which the tyrosine analogue is incorporated at the site encoded by the suppressor codon.