Structural bases of the functions of RNA-protein machines - Project 5

识别小分子配体的RNA在生物中提供了一种广泛的调节机制 系统。这项研究的重点是三种对小分子有反应，但方式截然不同的RNA。 将对I族自剪接RNA、合作甘氨酸核糖开关和一种新的 发现了与第二信使环二鸟苷一磷酸(c-diGMP)反应的核糖开关。 1.小分子底物鸟苷对RNA的剪接反应。RNA剪接是去除 成熟细胞RNA产生中的一个内含子及其两侧外显子的同时连接 分子。虽然大多数内含子被剪接体移除，但一些内含子能够催化自己的内含子 从主要成绩单中删除。第一类内含子的发现提供了第一个迹象 并非所有的酶都是蛋白质。我们的目标是从结构上描述RNA拼接的每一步 为了了解RNA是如何作为催化剂发挥作用的。 2.通过与氨基酸甘氨酸的协同结合调控基因表达。核糖开关是 动态RNA折叠结构域结合特定代谢物并通过调节 转录终止、翻译启动或RNA降解。该甘氨酸核糖开关包括两个 相似的适配子结构域，每个都与甘氨酸结合，但是协同作用的。其结果是一种数字RNA传感器 这对甘氨酸浓度特别敏感。我们的目标是了解甘氨酸的结构基础 约束性和协作性。 3.分析核糖开关对细胞内第二信使的反应。C-dGMP是最近发现的 作为一种广泛的核糖开关的配体，称为GEMM核糖开关。我们的目标是了解 这类新的RNA分子与c-diGMP结合的结构和生化基础。

RNAs that recognize small molecule ligands provide a widespread regulatory mechanism in biological systems. This study focuses on three RNAs that respond to small molecules, but in very different ways. Studies will be performed on the group I self-splicing RNA, the cooperative glycine riboswitch and a newly discovered riboswitch responsive to the second messenger cyclic diguanosine monophosphate (c-diGMP). 1. RNA splicing in response to the small molecule substrate guanosine. RNA splicing is the removal of an intron and the simultaneous ligation of its flanking exons in the generation of mature cellular RNA molecules. While most introns are removed by the spliceosome, some introns are able to catalyze their own removal from the primary transcript. The discovery of the group I class of introns provided the first indication that not all enzymes are proteins. Our goal is to structurally characterize each step in an RNA splicing pathway in order to understand how RNA functions as a catalyst. 2. Control of gene expression by cooperative binding of the amino acid glycine. Riboswitches are dynamic RNA folding domains that bind specific metabolites and control gene expression by modulation of transcription termination, translation initiation or RNA degradation. The glycine riboswitch comprises two similar aptamer domains that each bind glycine, but do so cooperatively. The result is a digital RNA sensor that is particularly sensitive to glycine concentration. Our goal is to understand the structural basis of glycine binding and cooperativity. 3. Analysis of a riboswitch responsive to a second messenger in the cell. c-dGMP was recently identified as a ligand for a broad collection of riboswitches, termed GEMM riboswitches. Our goal is to understand the structural and biochemical basis of c-diGMP binding by this new class of RNA molecule.