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Structural basis for RNA function in ribonucleoprotein complex

核糖核蛋白复合物中RNA功能的结构基础

基本信息

批准号：
17370036
负责人：
NUREKI Osamu
金额：
$ 10.02万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Proteins associate and collaborate with RNAs to form ribonucleoproteins, which act in highly specific genetic information transfer process. In this study, we first focused on tRNA processing and post-translational modification. We solved the crystal structures of CCA-adding enzymes complexed with tRNA primer at each reaction step (Nature, 2006), MnmA thiouridine synthetase complexed with tRNA in three reaction steps (Nature, 2006), and TilS lysidine synthetase complexed with tRNA^<Ile2> (Nature, 2009) and revealed their dynamic RNA recognition and catalytic mechanism at an atomic resolution. Second, in eukarya and archaea, tRNA modifying and activating enzymes form channeling ribonucleoprotein complex with their cognate tRNA to fulfil the complex sequential chemical reactions. We solved the crystal structure of tRNA-dependent amidotransferase GatDE in a complex with tRNAGIn to show how the complex catalyzes three sequential reactions (Science, 2006). We further solved the crystal strictures of 3 out of 5 enzymes involved in synthesis of yW hypermodification in position 37 of eukaryotic and archaeal tRNA^<Phe> (J.Mol.Biol., 2008 ; Nucleic Acids Res., 2009 ; Proc.Natl.Acad.Sci.USA, 2009). These studies revealed how each enzyme utilizes S-adenosyl-methionine cofactor in different way to achieve the sequential modification reaction. Finally, we solved the crystal structure as well as biochemical analysis of Sec translocon machinery, acting in translocation of thus synthesized protein in cytoplasm across the membrane (Nature, 2009). We thus showed that SecYE channel and SecA molecular motor mutually transit their conformation from closed to open form to activate each other to achieve the protein translocation.

蛋白质与RNA结合并协作形成核糖核蛋白，核糖核蛋白在高度特异的遗传信息传递过程中发挥作用。在本研究中，我们首先关注tRNA的加工和翻译后修饰。我们解决了CCA添加酶在每个反应步骤中与tRNA引物络合(Natural，2006)、MnmA硫代尿苷合成酶与tRNA在三个反应步骤中络合(Natural，2006)、TILs赖氨酸合成酶与tRNA^&lt；Ile2&gt；(Nature，2009)的晶体结构，并从原子分辨率上揭示了它们的动态RNA识别和催化机理。其次，在真核生物和古生物中，tRNA修饰和激活酶与它们的同源tRNA形成通道核糖核蛋白复合体，完成复杂的顺序化学反应。我们在与tRNAGIn的络合物中求解了tRNA依赖的氨基转移酶GatDE的晶体结构，以显示该络合物如何催化三个顺序的反应(Science，2006)。我们进一步解决了参与合成YW的5个酶中的3个的晶体结构，这些酶位于真核和古生物tRNA^&lt；Phe&gt；37位(J.Mol.Biol，2008；Nucleic Res.，2009；Proc.Natl.Academy.Science，2009)。这些研究揭示了每个酶是如何以不同的方式利用S-腺苷-蛋氨酸辅因子来实现序贯修饰反应的。最后，我们解决了SEC易位机制的晶体结构以及生化分析，该机制作用于这样合成的蛋白质在细胞质中的跨膜转运(自然，2009)。结果表明，SecYE通道和SecA分子马达相互转换构象，从封闭状态转变为开放状态，相互激活，实现蛋白质的易位。