RNA-ENZYME RECOGNITION CODES IN AMINOACYL-TRNA SYNTHESIS AND TRNA MODIFICATION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。遗传密码是由20种酶（氨基酰基- trna合成酶）组成的系统建立的，这些酶将特定的氨基酸连接到携带氨基酸同源反密码子序列的trna上。同样，最近有人提出，更多的tRNA修饰酶根据复杂的识别代码结合到它们的RNA底物上。我们想要了解这些酶高度特异性tRNA识别的结构基础。一种被充分研究的合成酶是丙烯酰- trna合成酶，它最近被晶体学破译（Swairjo et al., Mol. Cell.）。科学通报，2004,13(6):829-841。该合成酶识别其同源tRNA在受体茎中保守的G:U碱基对上，而对tRNA反密码子不敏感。我们有AlaRS的大晶体与模仿tRNAAla受体茎的RNA底物络合。同样，YHDG和Ykvm是两种新的酶，参与两种不同的特异性tRNA修饰。我们有Ykvm的晶体，目前正在进行tRNA复合体的结晶试验。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The genetic code is established by a system of 20 enzymes, aminoacyl-tRNA synthetases, which attach specific amino acids to tRNAs carrying anti-codon sequences cognate for the amino acid. Similarly, it has been recently proposed that the more numerous tRNA modification enzymes bind to their RNA substrates according to a complex recognition code. We want to understand the structural basis of highly specific tRNA recognition by these enzymes. A well studied synthetase is alanyl-tRNA synthetase which has been recently crystallographically deciphered (Swairjo et al., Mol. Cell., 2004, 13(6):829-841). This synthetase recognizes its cognate tRNA at a conserved G:U base pair in the acceptor stem, and is indifferent toward the tRNA anticodon. We have large crystals of AlaRS complexed with an RNA substrate mimicking the acceptor stem of tRNAAla. Similarly, YHDG and Ykvm are two novel enzymes involved in two different and specific tRNA modifications. We have crystals of Ykvm, and are currently persuing its tRNA complex with crystaliization trials.