Aminoacylation complex structures of leucyl-tRNA synthetase and tRNALeu reveal two modes of discriminator-base recognition
Aminoacylation complex structures of leucyl-tRNA synthetase and tRNALeu reveal two modes of discriminator-base recognition
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DOI：
10.1038/nsmb985
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发表时间：
2005-10-01
影响因子：
16.8
通讯作者：
Yokoyama, S
中科院分区：
文献类型：
--
作者：
Fukunaga, R;Yokoyama, S
亮氨酰-tRNA合成酶（LeuRS）特异性识别古细菌和真核生物中tRNALeu的特征性长可变臂和碱基A73。LeuRS“编辑结构域”水解错误形成的非同源氨酰-tRNA。在这里，我们报告的古细菌Pyrococcus horikoshii LeuRS-tRNA（Leu）复合物的晶体结构。LeuRS的C端突出结构域特异性识别长可变臂顶端的碱基，编辑结构域从其不含tRNA的位置摆动，以避免与tRNA发生冲突。因此，tRNA CCA末端可以弯曲并到达氨酰化活性位点。tRNA 3'区呈现两种不同的构象，使A73以不同的方式被特异性识别。一种构象是典型的氨酰化状态。另一种构象似乎是“中间状态”，其中错氨基酰化的3'端部分重新定位到编辑结构域。
Leucyl-tRNA synthetase (LeuRS) specifically recognizes the characteristic long variable arm and the discriminator base, A73, of tRNALeu in archaea and eukarya. The LeuRS 'editing domain' hydrolyzes misformed noncognate aminoacyl-tRNA. Here we report the crystal structure of the archaeal Pyrococcus horikoshii LeuRS-tRNA(Leu) complex. The protruding C-terminal domain of LeuRS specifically recognizes the bases at the tip of the long variable arm. The editing domain swings from its tRNA-free position to avoid clashing with the tRNA. Consequently the tRNA CCA end can bend and reach the aminoacylation active site. The tRNA 3' region assumes two distinct conformations that allow A73 to be specifically recognized in different ways. One conformation is the canonical 'aminoacylation state.' The other conformation seems to be the 'intermediate state,' where the misaminoacylated 3' end has partially relocated to the editing domain.