Tyrosyl-trna syntiiase variants

摘要

Tyrosyl-tRNA synthetases having a modified amino acid sequence whereby unnatural amino acids can be more efficiently incorporated than original natural amino acids. More specifically, tyrosyl-tRNA synthetases having been modified at the amino acid(s) at the 37- and/or 195-positions. A method of modifying tyrosyl-tRNA synthetase characterized in that the position of an amino acid to be modified is determined based on the 3-D structure of a tyrosyl-AMP and of tyrosyl synthetase complex and an amino acid to which this enzyme binds.