[Mechanism of discrimination of tRNA(Phe) from E. coli by yeast phenylalanine-tRNA-synthetase].
Some peculiarities of aminoacylation of homologous and heterologous tRNA by yeast phenylalanyl-tRNA synthetase have been studied. It was found that the enzyme is inactivated during E. coli tRNA aminoacylation due to the formation of a pyrophosphorylated form of the enzyme. Inorganic pyrophosphatase splits off the bound pyrophosphate and reactivates the enzyme; a similar effect is produced by homologous tRNA. The differences in the reaction mechanism observed with E. coli tRNA in comparison with yeast tRNA seem to be due to the sole difference in the nucleotide sequences, i. e., substitution of G-U at position 20. A putative mechanism of the enzyme inactivation during aminoacylation of heterologous tRNA is discussed.
Khvorova
A M
AM
Motorin
Iu A
IuA
Vol'fson
A D
AD
D000215:Acylation; D011756:Diphosphates / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism*; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism*; D011755:Pyrophosphatases / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D011756:Diphosphates; D012360:RNA, Transfer, Phe; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase; D010652:Phenylalanine-tRNA Ligase