EVOLUTION OF THE GLX-TRANSFER-RNA SYNTHETASE FAMILY - THE GLUTAMINYL ENZYME AS A CASE OF HORIZONTAL GENE-TRANSFER
EVOLUTION OF THE GLX-TRANSFER-RNA SYNTHETASE FAMILY - THE GLUTAMINYL ENZYME AS A CASE OF HORIZONTAL GENE-TRANSFER
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DOI：
10.1073/pnas.91.18.8670
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发表时间：
1994-08-30
影响因子：
11.1
通讯作者：
MIRANDE, M
中科院分区：
文献类型：
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作者：
LAMOUR, V;QUEVILLON, S;MIRANDE, M
确保蛋白质生物合成保真度的一个重要步骤是氨酰-tRNA合成酶对tRNA的氨酰化。这个过程的准确性取决于一个由20种酶组成的家族，每种酶对应一种氨基酸。一个例外是Gln-tRNA（Gln）的形成，其可以通过两种不同的途径完成：通过双氨酰-tRNA合成酶（GlnRS; EC 6.1.1.18）用Gln氨酰化tRNA（Gln）或通过谷氨酰-tRNA合成酶（GluRS; EC 6.1.1.17）从错电荷的Glu-tRNA（Gln）转酰胺化Glu。后一种途径在相应地缺乏GlnRS的细菌和细胞器中广泛存在。然而，一些细菌物种，如大肠杆菌，确实具有GlnRS活性，其负责Gln-tRNA（Gln）的形成。在真核细胞的细胞质中，GluRS和GlnRS活性都可以被检测到。为了更深入地了解GluRS和GlnRS酶物种之间的进化关系，我们现在已经分离并表征了编码GlnRS的人cDNA。推导的氨基酸序列与其他已知GlnRS和真核GluRS具有很强的相似性。对14个GlxRS（GluRS或GlnRS）序列进行了分子系统发育分析。我们的数据表明，细菌GlnRS具有真核起源，并通过水平基因转移的机制获得。
An important step ensuring the fidelity in protein biosynthesis is the aminoacylation of tRNAs by aminoacyl-tRNA synthetases. The accuracy of this process rests on a family of 20 enzymes, one for each amino acid. One exception is the formation of Gln-tRNA(Gln) that can be accomplished by two different pathways: aminoacylation of tRNA(Gln) with Gln by glutaminyl-tRNA synthetase (GlnRS; EC 6.1.1.18) or transamidation of Glu from Glu-tRNA(Gln) mischarged by glutamyl-tRNA synthetase (GluRS; EC 6.1.1.17). The latter pathway is widespread among bacteria and organelles that, accordingly, lack GlnRS. However, some bacterial species, such as Escherichia coli, do possess a GlnRS activity, which is responsible for Gln-tRNA(Gln) formation. In the cytoplasm of eukaryotic cells, both GluRS and GlnRS activities can be detected. To gain more insight into the evolutionary relationship between GluRS and GlnRS enzyme species, we have now isolated and characterized a human cDNA encoding GlnRS. The deduced amino acid sequence shows a strong similarity with other known GlnRSs and with eukaryotic GluRSs. A molecular phylogenetic analysis was conducted on the 14 GlxRS (GluRS or GlnRS) sequences available to date. Our data suggest that bacterial GlnRS has a eukaryotic origin and was acquired by a mechanism of horizontal gene transfer.