Leucyl-tRNA synthetase from the ancestral bacterium Aquifex aeolicus contains relics of synthetase evolution
Leucyl-tRNA synthetase from the ancestral bacterium Aquifex aeolicus contains relics of synthetase evolution
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来自祖先细菌 Aquifex aeolicus 的亮氨酰-tRNA 合成酶包含合成酶进化的遗迹
DOI：
10.1038/sj.emboj.7600618
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发表时间：
2005-04-06
期刊：
影响因子：
11.4
通讯作者：
Wang, ED
中科院分区：
文献类型：
--
作者：
Zhao, MW;Zhu, B;Wang, ED
由氨基酰-tRNA合成酶催化的编辑反应通过纠正错误激活的氨基酸和错误的氨基酰化tRNA，对于忠实的蛋白质合成至关重要。我们报道了从根深蒂固的细菌Aquifex aeolicus(α-beta-leur)中分离的亮氨酰-tRNA合成酶的编辑结构域能够催化错误荷电的tRNA(Leu)和微型螺旋(Leu)的水解性编辑。在这个结构域中，我们已经确定了一个关键的20个氨基酸的多肽，当移植到不活跃的大肠杆菌LeuS编辑结构域中时，它可以赋予编辑能力。同样，将α-β-LeuS的β-亚基融合到大肠杆菌的编辑结构域可激活其编辑功能。这些结果表明，α-β-Leur仍然具有原始合成酶分子的基本特征。它具有显著的转移自主活性模块的能力，这与现代合成酶是在交换小的特殊结构域后产生的想法是一致的。它还具有独特的α-β-异二聚体结构，具有分离的催化和tRNA结合位点。这样的组织支持tRNA/合成酶共同进化理论，该理论预测tRNA和合成酶结构域的顺序添加。
The editing reactions catalyzed by aminoacyl-tRNA synthetases are critical for the faithful protein synthesis by correcting misactivated amino acids and misamino-acylated tRNAs. We report that the isolated editing domain of leucyl-tRNA synthetase from the deep-rooted bacterium Aquifex aeolicus (alpha beta-LeuRS) catalyzes the hydrolytic editing of both mischarged tRNA(Leu) and minihelix(Leu). Within the domain, we have identified a crucial 20-amino-acid peptide that confers editing capacity when transplanted into the inactive Escherichia coli LeuRS editing domain. Likewise, fusion of the beta-subunit of alpha beta-LeuRS to the E. coli editing domain activates its editing function. These results suggest that alpha beta-LeuRS still carries the basic features from a primitive synthetase molecule. It has a remarkable capacity to transfer autonomous active modules, which is consistent with the idea that modern synthetases arose after exchange of small idiosyncratic domains. It also has a unique alpha beta-heterodimeric structure with separated catalytic and tRNA-binding sites. Such an organization supports the tRNA/synthetase coevolution theory that predicts sequential addition of tRNA and synthetase domains.