Patent ID: 7566555

Claim:
An expression method for non-naturally-occurring amino acid-containing proteins comprising: expressing in isolated animal cells: (A) a mutant tyrosyl-tRNA synthetase comprising a substitution from tyrosine to valine at position 37 and glutamine to cysteine at position 195 (V37C195) in the tyrosyl tRNA synthetase of SEQ ID NO:29 wherein said synthetase has enhanced specificity for a non-naturally-occurring tyrosine derivative selected from the group consisting of 3-iodotyrosine and 3-bromotyrosine, as compared to the specificity for tyrosine; (B) Bacillus stearothermophilus suppressor tyrosyl tRNA (tRNA Tyr ) capable of being aminoacylated with the tyrosine derivative in the presence of the mutant tyrosyl tRNA synthetase; and, (C) a gene encoding a desired protein comprising a nonsense mutation at a desired site; wherein, the tyrosine derivative is incorporated in the desired protein in response to the nonsense mutation.