Biopolym. Cell. 1993; 9(6):31-35.
Structure and Function of Biopolymers
Conformational change of tyrosyl-tRNA synthetase from bovine liver in the course of cognate tRNA binding revealed from fluorescence spectroscopy data
1Klimenko I. V., 1Kornelyuk A. I., 1Matsuka G. Kh.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680
The fluorescent probe 1,5-1-AEDANS was covalently attached to tyrosyl-tRNA synthetase from bovine liver in a nearly stoichiometric amount (2 molecules of probe per enzyme dimer). Singlet-singlet energy transfer has been used for measurement of the apparent distance, between 6 tryptophan residues of enzyme and covalently attached 1,5-1-AEDANS. This distance was about 27.4 A assuming the random orientation of the donor and acceptor from polarization measurements. The interaction of cognate. tRNATyr with bovine tyrosyl-tRNA synthetase also resulted in the enhancement of fluorescence of AEDANS-labelled tyrosyRRNA synthetase (25 %) due to the increase of energy transfer efficiency. After binding of cognate bovine tRNATyr the apparent distance between tryptophan residues and AEDANS probe reduced to 25.3 A E. coli tRNATyr which was not aminoacylated by bovine enzyme did not induced these effects. Adding of ATP to the complex of bovine tRNATyr and tyrosyl-tRNA synthetase exhibited further enhancement of AEDANS fluorescence by 32 %. In this case the apparent distance between tryptophan residues and AEDANS probe was 24.1 A. These results are consistent with the conformational change of mammalian tyrosyl-tRNA synthetase, in the course of recognition of cognate tRNATyr.