Protein-Facilitates RNA Catalysts

蛋白质促进 RNA 催化剂

• 批准号: 6866400
• 负责人: Kevin M Weeks
• 金额: $ 24.73万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6866400
• 关键词: DNA footprinting; RNA binding protein; RNA biosynthesis; RNA splicing; X ray crystallography; catalyst; chemical kinetics; enzyme activity; enzyme complex; helicase; nucleic acid sequence; nucleic acid structure; protein biosynthesis; protein structure function; ribonucleoproteins; ribozymes; thermodynamics

DESCRIPTION (provided by applicant): The broad objective of this project is to understand how RNA and protein molecules assemble to form native ribonucleoprotein complexes and collaborate to perform RNA-based catalysis. In the first system, we will explore assembly of the bl5 ribonucleoprotein, consisting of the bl5 group I intron RNA and its single obligatory protein cofactor, CBP2. In particular, we will use this system to understand the structure of the RNA collapsed state, identified in the P.l.'s lab, that forms prior to subsequent assembly with the CBP2 protein cofactor. It is becoming clear that related collapsed states play fundamental, productive, roles in many RNA folding and ribonucleoprotein assembly reactions. The second system is the bl3 group I intron ribonucleoprotein. Splicing by the bl3 intron requires two facilitating proteins. The intron-encoded bl3 maturase binds a monomer; whereas, two Mrs1 dimers bind, cooperatively, to yield a six-component complex. The bl3 ribonucleoprotein will be developed as a model for understanding ribonucleoproteins that require binding by multiple protein cofactors to achieve a biologically functional state. Both simple systems are sufficiently sophisticated to illustrate principles generalizable to biomedically important ribonucleoproteins like the ribosome and pre-mRNA complexes. Specific aims are: (1) To determine the physical basis by which the collapsed state functions to prevent mis-assembly of the bl5 ribonucleoprotein. (2) To study the structure of the bl5 RNA under conditions likely to predominate in yeast mitochondria. (3) To understand the molecular basis for the predominance of near-native structures in the bl5 collapsed state. (4) To develop a comprehensive kinetic and thermodynamic framework for assembly of the six-component bl3 group I intron RNP catalyst. (5) To begin to explore the molecular mechanism by which Mrs1 facilitates catalysis of the bl3 group I intron. (6) To develop a high resolution model for the maturase-bl3 RNA complex.

描述（由申请人提供）： 该项目的广泛目的是了解RNA和蛋白质分子如何组装以形成天然核糖核蛋白复合物并协作以进行基于RNA的催化。在第一个系统中，我们将探索BL5核糖核蛋白的组装，该组合由BL5 I组内含子RNA及其单个强制性蛋白质辅助因子CBP2组成。特别是，我们将使用该系统来理解在P.L.实验室中鉴定出的RNA折叠状态的结构，该结构在随后与CBP2蛋白辅因子组装之前形成。很明显，相关的崩溃状态在许多RNA折叠和核糖核蛋白组装反应中起基本，富有生产力的作用。第二个系统是BL3组I内含子核糖核蛋白。 BL3内含子的剪接需要两个促进的蛋白质。内含子编码的BL3成熟酶结合单体；而两个MRS1二聚体合作结合，以产生六组分的复合物。将开发BL3核糖核蛋白作为理解需要多种蛋白质辅因子结合以实现生物学功能状态的核糖核蛋白的模型。两个简单的系统都足够复杂，可以说明可推广到生物医学重要的核糖核蛋白（如核糖体和前MRNA复合物）的原理。具体目的是：（1）确定折叠状态功能以防止BL5核糖核蛋白的错误组装的物理基础。 （2）在可能在酵母线粒体中占主导地位的条件下研究BL5 RNA的结构。 （3）了解BL5倒塌状态下近本性结构占主导地位的分子基础。 （4）为六组分BL3组I内含子RNP催化剂组装而开发一个全面的动力学和热力学框架。 （5）开始探索MRS1促进BL3 I组内含子催化的分子机制。 （6）为成熟酶-BL3 RNA复合物开发高分辨率模型。