Recognition of human mitochondrial tRNA Leu(UUR) by its cognate leucyl-tRNA synthetase
Recognition of human mitochondrial tRNA Leu(UUR) by its cognate leucyl-tRNA synthetase
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DOI：
10.1016/j.jmb.2004.03.066
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发表时间：
2004-05-21
影响因子：
5.6
通讯作者：
Florentz, C
中科院分区：
文献类型：
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作者：
Sohm, N;Sissler, M;Florentz, C
蛋白质合成的准确性取决于tRNAs通过其同源氨酰-tRNA合成酶的特异性识别和氨酰化。许多原核和真核细胞质系统已经建立了管理这些过程的规则，但只有有限的信息可用于人类线粒体系统。已经显示，体外转录的人线粒体tRNA（Leu（UUR））不折叠成预期的苜蓿叶，但是被人线粒体亮氨酰-tRNA合成酶氨酰化。在这里，研究了tRNA的氨基酸受体分支和反密码子分支（Leu（UUR））的结构在亮氨酰-tRNA合成酶识别中的作用。测定了野生型和突变型tRNA（LEU（UUR））转录物和天然tRNA（Leu（UUR））氨酰化的动力学参数。在存在或不存在亮氨酰-tRNA合成酶的情况下进行溶液结构探测，并与每个tRNA的氨酰化动力学相关。用G-C碱基对替换野生型tRNA（Leu（UUR））中存在的反密码子尾或D尾中的错配足以诱导（i）三叶草折叠，（ii）提高氨酰化效率，以及（iii）与合成酶的相互作用，这些相互作用与天然tRNA（Leu（UUR））的相互作用相似。亮氨酰-tRNA合成酶在氨基酸受体茎、反密码子茎和D环中接触tRNA（Leu（UUR）），这对于亮氨酸氨酰化系统是前所未有的。(C)2004爱思唯尔有限公司保留所有权利。
Accuracy of protein synthesis depends on specific recognition and amino-acylation of tRNAs by their cognate aminoacyl-tRNA synthetases. Rules governing these processes have been established for numerous prokaryotic and eukaryotic cytoplasmic systems, but only limited information is available for human mitochondrial systems. It has been shown that the in vitro transcribed human mitochondrial tRNA(Leu(UUR)) does not fold into the expected cloverleaf, but is however aminoacylated by the human mitochondrial leucyl-tRNA synthetase. Here, the role of the structure of the amino acid acceptor branch and the anticodon branch of tRNA(Leu(UUR)) in recognition by leucyl-tRNA synthetase was investigated. The kinetic parameters for aminoacylation of wild-type and mutant tRNA(LEU(UUR)) transcripts and of native tRNA(Leu(UUR)) were determined. Solution structure probing was performed in the presence or in the absence of leucyl-tRNA synthetase and correlated with the aminoacylation kinetics for each tRNA. Replacement of mismatches in either the anticodon-stern or D-stern that are present in the wild-type tRNA(Leu(UUR)) by G-C base-pairs is sufficient to induce (i) cloverleaf folding, (ii) improved aminoacylation efficiency, and (iii) interactions with the synthetase that are similar to those with the native tRNA(Leu(UUR)). Leucyl-tRNA synthetase contacts tRNA(Leu(UUR)) in the amino acid acceptor stem, the anticodon stem, and the D-loop, which is unprecedented for a leucine aminoacylation system. (C) 2004 Elsevier Ltd. All rights reserved.