Publications

• A single glutamyl-tRNA synthetase aminoacylates tRNAGlu and tRNAGln in Bacillus subtilis and efficiently misacylates Escherichia coli tRNAGln1 in vitro.

  Lapointe J., Duplain L., Proulx M.

  In the presence or absence of its regulatory factor, the monomeric glutamyl-tRNA synthetase from Bacillus subtilis can aminoacylate in vitro with glutamate both tRNAGlu and tRNAGln from B. subtilis and tRNAGln1 but not tRNAGln2 or tRNAGlu from Escherichia coli. The Km and Vmax values of the enzyme ... >> More

  In the presence or absence of its regulatory factor, the monomeric glutamyl-tRNA synthetase from Bacillus subtilis can aminoacylate in vitro with glutamate both tRNAGlu and tRNAGln from B. subtilis and tRNAGln1 but not tRNAGln2 or tRNAGlu from Escherichia coli. The Km and Vmax values of the enzyme for its substrates in these homologous or heterologous aminoacylation reactions are very similar. This enzyme is the only aminoacyl-tRNA synthetase reported to aminoacylate with normal kinetic parameters two tRNA species coding for different amino acids and to misacylate at a high rate a heterologous tRNA under normal aminoacylation conditions. The exceptional lack of specificity of this enzyme for its tRNAGlu and tRNAGln substrates, together with structural and catalytic peculiarities shared with the E. coli glutamyl- and glutaminyl-tRNA synthetases, suggests the existence of a close evolutionary linkage between the aminoacyl-tRNA synthetases specific for glutamate and those specific for glutamine. A comparison of the primary structures of the three tRNAs efficiently charged by the B. subtilis glutamyl-tRNA synthetase with those of E. coli tRNAGlu and tRNAGln2 suggests that this enzyme interacts with the G64-C50 or G64-U50 in the T psi stem of its tRNA substrates. << Less

  J Bacteriol 165:88-93(1986) [PubMed] [EuropePMC]

• Major identity element of glutamine tRNAs from Bacillus subtilis and Escherichia coli in the reaction with B. subtilis glutamyl-tRNA synthetase.

  Kim S.I., Soll D.

  Early investigations revealed that Bacillus subtilis glutamyl-tRNA synthetase [GluRS (bs)] is responsible for aminoacylating both glutamate tRNA [tRNA(Glu) (bs)] and glutamine tRNA [tRNA(Gln) (bs)] with glutamate. The same Bacillus enzyme can also efficiently attach glutamate to one isoacceptor gl ... >> More

  Early investigations revealed that Bacillus subtilis glutamyl-tRNA synthetase [GluRS (bs)] is responsible for aminoacylating both glutamate tRNA [tRNA(Glu) (bs)] and glutamine tRNA [tRNA(Gln) (bs)] with glutamate. The same Bacillus enzyme can also efficiently attach glutamate to one isoacceptor glutamine tRNA [tRNA(Gln) (ec)] of Escherichia coli in vitro but not to tRNA2(Gln) (ec) and tRNA(Glu) (ec). To characterize identity elements of these glutamine tRNAs in the interaction with GluRS (bs), tRNA2(Gln) (ec), tRNA1(Gln) (ec), three other mutant glutamine tRNAs [tRNA2(Gln) (AU) (C34 --> U34), tRNA2(Gln) (12M) (C34 --> U34, 31A-U39 --> 31U-A39), and tRNA2(Gln) (M21) (64C --> G50 --> 64G-C50, 63U-A51 --> 63A-U51)] originated from tRNA2(Gln) (ec), tRNA(Gln) (bs), and a mutant tRNAM(Gln) (bs) whose U at the 34th position (U34), was replaced to C (C34), were produced in E. coli. All of the E. coli glutamine tRNAs containing U34 such as tRNA1(Gln), tRNA2(Gln) (AU), and tRNA2(Gln) (12M) could be charged with glutamate by GluRS (bs), whereas tRNA2(Gln) (ec) and its T-stem mutant tRNA2(Gln) (M21) containing C34 could not be charged by the same enzyme. The unique change of C34 to U34 of tRNA2(Gln) (ec) acquired glutamate acceptor activity by GluRS (bs). This result suggests that the U34 is the major identity element of tRNA1(Gln) (ec) in the recognition by GluRS (bs). The same situation was found in tRNA(Gln) (bs). The glutamate acceptor activity of tRNA(Gln) (bs) disappeared on replacement of U34 to C34. To find out whether modified bases in tRNA(Gln) (bs) are involved in the recognition by GluRS (bs), glutamylation of tRNA(Gln) (bs) produced by in vitro transcription was also examined but the in vitro transcript of tRNA(Gln) (bs) could not be charged with glutamic acid by GluRS (bs). All of these mean that the major recognition element for GluRS (bs) is U at the 34th position of both tRNA(Gln) (bs) and tRNA1(Gln) (ec) as a modified form. << Less

  Mol Cells 8:459-465(1998) [PubMed] [EuropePMC]

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