Structural basis for orthogonal tRNA specificities of tyrosyl-tRNA synthetases for genetic code expansion
Structural basis for orthogonal tRNA specificities of tyrosyl-tRNA synthetases for genetic code expansion
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DOI：
10.1038/nsb934
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发表时间：
2003-06-01
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影响因子：
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通讯作者：
Yokoyama, S
中科院分区：
文献类型：
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作者：
Kobayashi, T;Nureki, O;Yokoyama, S
古细菌/真核生物酪氨酰-tRNA合成酶（TyrRS）tRNA（Tyr）对不与它们的细菌对应物交叉反应。这种正交条件对于使用古菌对来扩展细菌遗传密码是必不可少的。在这项研究中，詹氏甲烷球菌TyrRS-tRNA（Tyr）L-酪氨酸复合物的结构，在1.95埃的分辨率下解决，揭示了这种古细菌TyrRS严格识别C1-G72碱基对，而细菌TyrRS识别G1-C72以不同的方式使用不同的残基。这些不同的tRNA识别模式形成了正交性的基础。常见的tRNA（Tyr）身份决定簇（α，A73和反密码子残基）也以不同于细菌TyrRS的方式被识别。基于这一发现，我们创造了一种突变体TyrRS，其用C34氨酰化琥珀抑制tRNA的效率是野生型酶的65倍。
The archaeal/eukaryotic tyrosyl-tRNA synthetase (TyrRS) tRNA(Tyr) pairs do not cross- react with their bacterial counterparts. This orthogonal condition is essential for using the archaeal pair to expand the bacterial genetic code.. In this study, the structure of the Methanococcus jannaschii TyrRS-tRNA(Tyr) L-tyrosine complex, solved at a resolution of 1.95 Angstrom, reveals that this archaeal TyrRS strictly recognizes the C1-G72 base pair, whereas the bacterial TyrRS recognizes the G1-C72 in a different manner using different residues. These diverse tRNA recognition modes form the basis for the orthogonality. The common tRNA(Tyr) identity determinants ( the discriminator, A73 and the anticodon residues) are also recognized in manners different from those of the bacterial TyrRS. Based on this finding, we created a mutant TyrRS that aminoacylates the amber suppressor tRNA with C34 65 times more efficiently than does the wild-type enzyme.