A present-day aminoacyl-tRNA synthetase with ancestral editing properties
A present-day aminoacyl-tRNA synthetase with ancestral editing properties
复制标题
具有祖先编辑特性的现代氨酰基-tRNA 合成酶
DOI：
10.1261/rna.228707
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发表时间：
2007-01-01
期刊：
影响因子：
4.5
通讯作者：
Wang, En-Duo
中科院分区：
文献类型：
--
作者：
Zhu, Bin;Zhao, Ming-Wei;Wang, En-Duo
亮氨酰-、异亮氨酰-和缬氨酰-tRNA合成酶形成相关氨酰-tRNA合成酶的亚组，其将相似的氨基酸连接到其同源tRNA。为了防止翻译过程中的氨基酸错误掺入，这些酶还通过转移后编辑机制水解带错电荷的tRNA。在这里，我们表明来自深分支细菌风产液菌的LeuRS编辑由三种酶产生的全套氨酰化tRNA：Ile-tRNA（Ile）、Val-tRNA（Ile）、Val-tRNA（瓦尔）、Thr-tRNA（瓦尔）和Ile-tRNA（Leu）。这种不寻常的放大编辑属性进行了研究，在一个模型的原始编辑系统包含一个复合微螺旋携带三重亮氨酸，异亮氨酸，缬氨酸身份模仿原始的tRNA前体。我们发现，独立的LeuRS编辑结构域可以编辑这种前体，而IleRS和ValRS编辑结构域。这些结果表明A. aeolicus LeuRS携带的编辑属性似乎比IleRS和ValRS更原始。他们认为A. aeolicus编辑结构域保留了来自祖先共同编辑结构域的模糊编辑特性，或者，这种可塑性是由特定的代谢适应引起的。
Leucyl-, isoleucyl-, and valyl-tRNA synthetases form a subgroup of related aminoacyl-tRNA synthetases that attach similar amino acids to their cognate tRNAs. To prevent amino acid misincorporation during translation, these enzymes also hydrolyze mischarged tRNAs through a post-transfer editing mechanism. Here we show that LeuRS from the deep-branching bacterium Aquifex aeolicus edits the complete set of aminoacylated tRNAs generated by the three enzymes: Ile- tRNA(Ile), Val-tRNA(Ile), Val-tRNA(Val), Thr-tRNA(Val), and Ile-tRNA(Leu). This unusual enlarged editing property was studied in a model of a primitive editing system containing a composite minihelix carrying the triple leucine, isoleucine, and valine identity mimicking the primitive tRNA precursor. We found that the freestanding LeuRS editing domain can edit this precursor in contrast to IleRS and ValRS editing domains. These results suggest that A. aeolicus LeuRS carries editing properties that seem more primitive than those of IleRS and ValRS. They suggest that the A. aeolicus editing domain has preserved the ambiguous editing property from the ancestral common editing domain or, alternatively, that this plasticity results from a specific metabolic adaptation.