Site-Directed Mutagenesis of Tryptophan Residues in the Structure of the Catalytic Module of Tyrosyl-tRNA Synthetase from Bos taurus

Site-directed mutagenesis of the N-terminal catalytic module of Bos taurus tyrosyl-tRNA synthetase (mini-BtTyrRS) with the substitution of three Trp residues by Ala residues in its structure using the modified QuikChange method was performed to study structural dynamic and functional properties of the protein by fluorescence spectroscopy. Point substitutions of tryptophan codons TGG with alanine codons GCG in the cDNA nucleotide sequence of the tyrosyl-tRNA synthetase catalytic module cloned in expression plasmid pET-30a were obtained during sequential PCR reactions using the developed primers. As a result, mini-BtTyrRS cDNAs, whose sequences contain only one tryptophan codon in each of the three positions in the protein structure, were obtained.