Saito H, Watanabe K, Suga H
Department of Chemistry, State University of New York, Buffalo 14260-3000, USA.
RNA. 2001 Dec;7(12):1867-78.
We have recently reported an in vitro-evolved precursor tRNA (pre-tRNA) that is able to catalyze aminoacylation on its own 3'-hydroxyl group. This catalytic pre-tRNA is susceptible to RNase P RNA, generating the 5'-leader ribozyme and mature tRNA. The 5'-leader ribozyme is also capable of aminoacylating the tRNA in trans, thus acting as an aminoacyl-tRNA synthetase-like ribozyme (ARS-like ribozyme). Here we report its structural characterization that reveals the essential catalytic core. The ribozyme consists of three stem-loops connected by two junction regions. The chemical probing analyses show that a U-rich region (U59-U62 in J2a/3 and U67-U68 in L3) of the ribozyme is responsible for the recognition of the phenylalanine substrate. Moreover, a GGU-motif (G70-U72) of the ribozyme, adjacent to the U-rich region, forms base pairs with the tRNA 3' terminus. Our demonstration shows that simple RNA motifs can recognize both the amino acid and tRNA simultaneously, thus aminoacylating the 3' terminus of tRNA in trans.
我们最近报道了一种体外进化的前体tRNA（pre-tRNA），它能够在自身的3'-羟基上催化氨酰化反应。这种具有催化活性的pre-tRNA对RNase P RNA敏感，可产生5'-前导核酶和成熟tRNA。5'-前导核酶也能够反式氨酰化tRNA，因此可作为一种类似氨酰-tRNA合成酶的核酶（ARS样核酶）。在此，我们报道了其结构特征，揭示了关键的催化核心。该核酶由三个茎环结构通过两个连接区域相连组成。化学探针分析表明，核酶富含尿嘧啶的区域（J2a/3中的U59-U62和L3中的U67-U68）负责识别苯丙氨酸底物。此外，核酶中与富含尿嘧啶区域相邻的GGU基序（G70-U72）与tRNA 3'末端形成碱基对。我们的研究表明，简单的RNA基序能够同时识别氨基酸和tRNA，从而反式氨酰化tRNA的3'末端。
