Aminoacylation of tRNA in the evolution of an aminoacyl-RNA synthetase
Aminoacylation of tRNA in the evolution of an aminoacyl-RNA synthetase
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DOI：
10.1073/pnas.95.23.13495
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发表时间：
1998-11-10
影响因子：
11.1
通讯作者：
Hou, YM
中科院分区：
文献类型：
--
作者：
Lipman, RSA;Hou, YM
氨基酰基-tRNA 合成酶通过将氨基酸与其同源 tRNA 连接来催化 tRNA 的氨酰化。同源 tRNA 的选择是由检查 tRNA 不同区域的单独结构域共同决定的。大肠杆菌的半胱氨酸-tRNA 合成酶具有选择包含 U73、GCA 反密码子和 tRNA L 形拐角处的特定三级结构的 tRNA 的结构域。大肠杆菌酶不能有效识别酵母或人 tRNA(Cys)，这表明 tRNA 氨酰化决定簇从大肠杆菌到酵母再到人类的进化，以及与这些决定簇相互作用的合成酶结构域的共同进化。通过相继将酵母和人类 tRNA (Cys) 修饰为可被大肠杆菌酶有效氨酰化的 tRNA，我们已经鉴定出对氨酰化很重要但在进化过程中发生分歧的 tRNA 决定因素。这些决定因素为合成酶结构域的分歧提供了线索。我们认为选择U73的结构域在进化中是保守的，相反，我们认为选择tRNA L形角的结构域在大肠杆菌和酵母分离后早期分叉，而选择含有GCA的反密码子环的结构域在酵母和人类分离后较晚分叉。
Aninoacyl-tRNA synthetases catalyze aminoacylation of tRNAs by joining an amino acid to its cognate tRNA. The selection of the cognate tRNA is jointly determined by separate structural domains that examine different regions of the tRNA. The cysteine-tRNA synthetase of Escherichia coli has domains that select for tRNAs containing U73, the GCA anticodon, and a specific tertiary structure at the corner of the tRNA L shape. The E. coli enzyme does not efficiently recognize the yeast or human tRNA(Cys), indicating the evolution of determinants for tRNA aminoacylation from E, coli to yeast to human and the coevolution of synthetase domains that interact with these determinants. By successively modifying the yeast and human tRNA(Cys) to ones that are efficiently aminoacylated by the E. coli enzyme, ne have identified determinants of the tRNA that are important for aminoacylation but that have diverged in the course of evolution. These determinants provide clues to the divergence of synthetase domains. We propose that the domain for selecting U73 is conserved in evolution, In contrast, we propose that the domain for selecting the corner of the tRNA L shape diverged early, after the separation between E, coli and yeast, while that for selecting the GCA-containing anticodon loop diverged late, after the separation between yeast and human.