Center for Medicinal Protein Network and Systems Biology, Seoul National University, Seoul 151-742, Republic of Korea.
Biochem Biophys Res Commun. 2013 Mar 8;432(2):281-6. doi: 10.1016/j.bbrc.2013.01.116. Epub 2013 Feb 8.
Aminoacyl-tRNA synthetases (ARSs) recognize a specific sequence or structural characteristics of their cognate tRNAs. To contribute to the understanding how these recognition sites were selected, we generated two different RNA libraries containing either 42mer or 70mer random sequence and used them to select RNA aptamers that specifically bound to methionyl-tRNA synthetase (MRS) of Mycobacterium tuberculosis. The aptamer pools selected from the two RNA libraries showed strong binding affinity and selectivity to M. tuberculosis MRS compared to that of the homologous Escherichia coli MRS. The RNA aptamers selected from the two completely unrelated RNA pools shared the octamer sequence including CAU and the anticodon sequence of tRNA(Met). The secondary structure prediction suggested that the octamer motif in the selected aptamers would form a loop similar to the anticodon loop of tRNA(Met). The results suggest that the RNA loop containing CAU triplet could selected as a major recognition site for MRS during evolution more or less regarding, and also showed that species-specific ARS inhibitors can be obtained by in vitro evolution.
氨酰-tRNA 合成酶（ARSs）识别其同源 tRNA 的特定序列或结构特征。为了帮助理解这些识别位点是如何被选择的，我们生成了两个包含 42 个碱基或 70 个碱基随机序列的不同 RNA 文库，并使用它们来筛选特异性结合结核分枝杆菌甲硫氨酰-tRNA 合成酶（MRS）的 RNA 适体。与同源的大肠杆菌 MRS 相比，从两个 RNA 文库中筛选出的适体库对 M. tuberculosis MRS 具有很强的结合亲和力和选择性。从两个完全不相关的 RNA 库中筛选出的 RNA 适体具有包含 CAU 的八聚体序列和 tRNA(Met)的反密码子序列。二级结构预测表明，所选适体中的八聚体基序将形成类似于 tRNA(Met)的反密码子环的环。结果表明，在进化过程中，包含 CAU 三核苷酸的 RNA 环可能或多或少地被选为 MRS 的主要识别位点，并且还表明可以通过体外进化获得物种特异性的 ARS 抑制剂。
