Leucyl-tRNA synthetase (LeuRS, EC 6.1.1.4) from E. coli underwent limitedproteolysis by trypsin which cut off 6K peptide and converted the intact LeuRS into a 96K fragment. The truncated enzyme retained the PPi exchan...Leucyl-tRNA synthetase (LeuRS, EC 6.1.1.4) from E. coli underwent limitedproteolysis by trypsin which cut off 6K peptide and converted the intact LeuRS into a 96K fragment. The truncated enzyme retained the PPi exchange activity with the same kinetic parameters as those of native LeuRS but lost the tRNA^(Leu)charging, binding and other tRNA^(Leu)-related activities. N-terminus analysis showed that the 6K peptide was located at the C-terminus of LeuRS. This small part played a crucial role in tRNA^(Leu) binding. Our results suggest that the two activities, PPi exchange and tRNA charging are independent of each other and correspond to different structural regions of LeuRS. The C-terminal region might be the tRNA^(Leu)binding site of LeuRS.展开更多
基金Project supported by the National Natural Science Foundation of China. Part of the results was presented at the 4th Congress of FAOB (Federation of Asian and Oceanian Biochemists) in 1986.
文摘Leucyl-tRNA synthetase (LeuRS, EC 6.1.1.4) from E. coli underwent limitedproteolysis by trypsin which cut off 6K peptide and converted the intact LeuRS into a 96K fragment. The truncated enzyme retained the PPi exchange activity with the same kinetic parameters as those of native LeuRS but lost the tRNA^(Leu)charging, binding and other tRNA^(Leu)-related activities. N-terminus analysis showed that the 6K peptide was located at the C-terminus of LeuRS. This small part played a crucial role in tRNA^(Leu) binding. Our results suggest that the two activities, PPi exchange and tRNA charging are independent of each other and correspond to different structural regions of LeuRS. The C-terminal region might be the tRNA^(Leu)binding site of LeuRS.
