Patent ID: 7785827

Claim:
A method for producing a mutated leucyl-tRNA synthetase that misaminoacylates non-leucine amino acids comprising the steps of: mutating one to three amino acids in a conserved editing active site region of a connective polypeptide 1 domain of a leucyl-tRNA synthetase, wherein the conserved editing active site region is selected from the group consisting of a threonine-rich region at a position corresponding to amino acids 247 to 257 relative to the E. coli leucyl-tRNA synthetase numbering and a region surrounding a conserved aspartic acid corresponding to amino acid 345 including seven amino acids preceding amino acid 345 relative to the E. coli leucyl-tRNA synthetase numbering, and combinations thereof, wherein mutating the one to three amino acids inactivates editing activity of the leucyl-tRNA synthetase and produces a mutated leucyl-tRNA synthetase that misaminoacylates non-leucine amino acids; and aminoacylating a tRNA molecule with the mutated leucyl-tRNA synthetase in the presence of at least one non-leucine amino acid, thereby aminoacylating the non-leucine amino acid onto the tRNA molecule, wherein the non-leucine amino acid is an amino acid activated by the mutated leucyl-tRNA synthetase.