STRUCTURAL INVESTIGATIONS OF RIBOZYMES

核酶的结构研究

• 批准号: 7721233
• 负责人: SCOTT A STROBEL
• 金额: $ 1.41万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-15 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7721233
• 关键词: Acids; Amines; Biochemical; Catalysis; Catalytic RNA; Chemicals; Chemistry; Computer Retrieval of Information on Scientific Projects Database; Down-Regulation; Enzymes; Event; Funding; Gram-Positive Bacteria; Grant; Institution; Introns; Investigation; Ions; Metals; Production; RNA; RNA Folding; Research; Research Personnel; Resources; Source; Structure; United States National Institutes of Health; Work; amino group; base; chemical reaction; cofactor; design; functional group; glucosamine 6-phosphate; insight; small molecule; sugar

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. We have been investigating structural aspects of catalysis by RNA enzymes. Our current work focuses on the group I intron and the metabolite responsive ribozyme, GlmS. The GlmS ribozyme is activated by the small sugar, glucosamine-6-phosphate (GlcN6P). This ribozyme is classified as a riboswitch, as the cleavage event results in the down regulation of GlcN6P production in many Gram positive bacteria. The precise chemical mechanism by which the RNA structure of the GlmS ribozyme promotes self cleavage is unknown. Does this nucleolytic ribozyme utilize catalytic metal ions, such as with the group I intron, or does it employ one or more of the heterocyclic bases for general acid or general base catalysis, such as the HDV ribozyme? Does the GlcN6P induce a conformational change to promote an activated RNA fold, or does one of its functional groups, such as the amino group, participate directly in the chemical reaction? If the latter is the case, it would be the first example of an RNA that utilizes a small molecule cofactor to promote chemistry. Interestingly, the amino group of GlcN6P is absolutely required for activity and the pKa of this amine varies with the pKa of the ribozyme. The crystal structure of this ribozyme would provide significant insight into these biochemical questions. It would also provide a structural framework for designing and interpreting all subsequent biochemical studies of this RNA.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 我们一直在研究 RNA 酶催化的结构方面。我们目前的工作重点是 I 组内含子和代谢物响应核酶 GlmS。 GlmS 核酶由小糖、6-磷酸氨基葡萄糖 (GlcN6P) 激活。这种核酶被归类为核糖开关，因为裂解事件会导致许多革兰氏阳性细菌中 GlcN6P 产生的下调。 GlmS 核酶的 RNA 结构促进自身裂解的精确化学机制尚不清楚。这种溶核核酶是否利用催化金属离子，例如 I 组内含子，或者它是否利用一种或多种杂环碱进行一般酸或一般碱催化，例如 HDV 核酶？ GlcN6P 是否会诱导构象变化以促进激活的 RNA 折叠，或者其功能基团之一（例如氨基）是否直接参与化学反应？ 如果是后者，这将是第一个利用小分子辅助因子促进化学反应的 RNA 例子。 有趣的是，GlcN6P 的氨基对于活性是绝对必需的，并且该胺的 pKa 随核酶的 pKa 变化。 这种核酶的晶体结构将为这些生化问题提供重要的见解。 它还将为设计和解释该 RNA 的所有后续生化研究提供结构框架。