Enzymatic aminoacylation of sequence-specific RNA minihelices and hybrid duplexes with methionine.
Enzymatic aminoacylation of sequence-specific RNA minihelices and hybrid duplexes with methionine.
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序列特异性 RNA 小螺旋和带有蛋氨酸的杂合双链体的酶促氨酰化。
DOI：
10.1073/pnas.89.1.65
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发表时间：
1992
影响因子：
11.1
通讯作者：
Schimmel,P
中科院分区：
文献类型：
--
作者：
Martinis,SA;Schimmel,P
RNA发夹螺旋的序列基于丙氨酸和组氨酸的受体茎，tRNAs与它们的同源氨基酸特异性地氨基酰化。在这些例子中，决定各自tRNAs身份的主要决定因素位于受体茎中；反密码子和tRNA的其他部分对于氨基酰化是必不可少的。相反，反密码子是蛋氨酸tRNA识别的主要决定因素。本文研究了分别构建蛋氨酸tRNA受体-T psi C茎和受体茎的RNA发夹螺旋和杂合双链与蛋氨酸的氨酰化反应。通过荧光成像在酸性聚丙烯酰胺凝胶上直接观察到氨酰化的RNA产物显示了与底物的特异性氨酰化反应，底物只包含7个碱基对。在几种基于非同源tRNAs序列的类似RNA底物中，没有检测到与蛋氨酸的氨酰化反应。虽然与蛋氨酸tRNA相比，氨酰化的效率降低了几个数量级，但结果表明，在没有tRNA的反密码子或其他结构域的情况下，小分子双链底物的甲硫氨酸可以实现特异性的氨酰化。结合早期的研究，这些结果表明氨基酰-tRNA合成酶的结构与其同源tRNAs的受体茎具有高度特异性的适应性，导致小RNA双链的核苷酸序列/结构与特定氨基酸之间的关系。
RNA hairpin helices whose sequences are based on the acceptor stems of alanine and histidine tRNAs are specifically aminoacylated with their cognate amino acids. In these examples, major determinants for the identities of the respective tRNAs reside in the acceptor stem; the anticodon and other parts of the tRNA are dispensable for aminoacylation. In contrast, the anticodon is a major determinant for the identity of a methionine tRNA. RNA hairpin helices and hybrid duplexes that reconstruct the acceptor-T psi C stem and the acceptor stem, respectively, of methionine tRNA were investigated here for aminoacylation with methionine. Direct visualization of the aminoacylated RNA product on an acidic polyacrylamide gel by phosphor imaging demonstrated specific aminoacylation with substrates that contained as few as 7 base pairs. No aminoacylation with methionine was detected with several analogous RNA substrates whose sequences were based on noncognate tRNAs. While the efficiency of aminoacylation is reduced by orders of magnitude relative to methionine tRNA, the results establish that specific aminoacylation with methionine of small duplex substrates can be achieved without the anticodon or other domains of the tRNA. The results, combined with earlier studies, suggest a highly specific adaptation of the structures of aminoacyl-tRNA synthetases to the acceptor stems of their cognate tRNAs, resulting in a relationship between the nucleotide sequences/structures of small RNA duplexes and specific amino acids.
谷氨酰胺酰-tRNA合成酶识别反密码子环的结构基础
影响因子：
64.8
作者：
M. A. Rould;J. Perona;T. Steitz
通讯作者：
T. Steitz