Biopolymers and cell. 1998; 14 (2): 144 - 151

Comparative study of the physical and chemical properties of the tyrosyl-tRNA synthetases from Thermus thermophilus and Escherichia coli

S. P. Egorova, A. D. Yaremchuk, M. A. Tukalo

A comparative study of the physical and chemical properties of the tyrosyl-tRNA synthetases from T^thermophilus and E. coli has been carried out. KM values for tRNA yr from T. termophilus and E. coli, for L-tyrosine and ATP, as well as their temperature dependences were determined. The KCl effects ^were studied for the amin^-acylation of the homologous tRNA yr and heterologous tRNA ~ species. A comparative analysis of amino acid composition of the tyrosyl-tRNA synthetases from T. thermophilus and E. coli has been carried out. Temperature dependences of tRNA aminoacylation and r PJPPi-ATP exchange rates and the thermostability curves for tyrosyl-tRNA synthetases from T. thermophilus and E. coli were determined.