Biopolymers and cell. 2001; 17 (6): 534 - 539

Kinetic parameters of the tRNA yr transcript aminoacylation by the bovine liver tyrosyl-tRNA synthetase

V. G. Naidenov, M. I. Vudmaska, G. Kh. Matsuka

The full-length tyrosyl-tRNA synthetase from bovine liver and its truncated form without the C-terminal noncatalytic domain were expressed in a bacterial system. Both enzymes have been compared in respect of the aminoacylation kinetic constants. It has been shown that the catalytic efficiency of the yeast tRNAyr and tRNAyr transcript tyrosylation upon deletion of the C-terminal domain decreases by factors of 4 and 18 respectively. The catalytic efficiency decrease in the tRNA ^ transcript tyrosylation is mainly due to the increasing of K.w We suggest that the C-terminal domain improves the aminoacylation activity of tyrosyl-tRNA synthetase by streng¬thening tRNA binding.