A SINGLE GLUTAMYL-TRANSFER RNA-SYNTHETASE AMINOACYLATES TRANSFER-RNA GLU AND TRANSFER-RNA GLN IN BACILLUS-SUBTILIS AND EFFICIENTLY MISACYLATES ESCHERICHIA-COLI TRANSFER RNA1GLN INVITRO
A SINGLE GLUTAMYL-TRANSFER RNA-SYNTHETASE AMINOACYLATES TRANSFER-RNA GLU AND TRANSFER-RNA GLN IN BACILLUS-SUBTILIS AND EFFICIENTLY MISACYLATES ESCHERICHIA-COLI TRANSFER RNA1GLN INVITRO
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DOI：
10.1128/jb.165.1.88-93.1986
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发表时间：
1986-01-01
影响因子：
3.2
通讯作者：
PROULX, M
中科院分区：
文献类型：
--
作者：
LAPOINTE, J;DUPLAIN, L;PROULX, M
在存在或不存在其调节因子的情况下，来自枯草杆菌的单体谷氨酰-tRNA合成酶可以在体外用谷氨酸对来自B的tRNAGlu和tRNAGIn进行氨酰化。枯草芽孢杆菌和tRNA 1Gln，而不是tRNA 2Gln或tRNAGlu从大肠杆菌。在这些同源或异源氨酰化反应中，酶对其底物的Km和Vmax值非常相似。这种酶是唯一的氨酰-tRNA合成酶，据报道，以正常的动力学参数氨酰化两种编码不同氨基酸的tRNA种类，并在正常的氨酰化条件下以高速率错酰化异源tRNA。这种酶对tRNAGlu和tRNAGln底物的特异性的异常缺乏，以及与E.大肠杆菌谷氨酰-和氨酰-tRNA合成酶，表明谷氨酸特异性的氨酰-tRNA合成酶和谷氨酰胺特异性的氨酰-tRNA合成酶之间存在密切的进化联系。通过B有效带电的三种tRNA的一级结构的比较。subtilis谷氨酰-tRNA合成酶与E. colitRNAGlu和tRNA 2Gln表明该酶与T. PSI中的G64-C50或G64-U 50相互作用。其tRNA底物的茎。
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 tRNA1Gln but not tRNA2Gln 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 shoared 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 tRNA2Gln suggests that this enzyme interacts with the G64-C50 or G64-U50 in the T.PSI. stem of its tRNA substrates.