CHARACTERIZATION OF NUCLEOTIDE DEPENDANT OLIOGOMERIC STATES OF RNR1P USING SAXS

使用 SAXS 表征 RNR1P 的核苷酸依赖性寡聚态

• 批准号: 8168654
• 负责人: Chris G Dealwis
• 金额: $ 1.08万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8168654
• 关键词: Accounting; Allosteric Regulation; Allosteric Site; Antineoplastic Agents; Behavior; Binding; Catalytic Domain; Cells; Complex; Computer Retrieval of Information on Scientific Projects Database; DNA biosynthesis; Deoxyribonucleotides; Funding; Grant; Institution; Modeling; Nucleotides; Production; Proliferating; Research; Research Personnel; Resources; Ribonucleotide Reductase; Ribonucleotide Reductase Subunit; Roentgen Rays; Site; Source; Specificity; United States National Institutes of Health; enzyme activity; inhibitor/antagonist

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. Ribonucleotide reductase (RNR) catalyzes the rate-limiting step in production of the pool of deoxyribonucleotides necessary for DNA replication. Crucial for rapidly proliferating cells, RNR is a successful target for anti-HSV and anticancer drugs. Allosteric regulation consitutes one of the important modes of regualtion of RNR activity.Currently, there are two major models that describe the allosteric behavior of RNR. The model proposed by Reichard and Thelander (RT model) accounts that the substrate binding at the catalytic site (c-site) is governed by a given dNTP bound to the specificity site (s-site), while global enzyme activity is dependent on either ATP or dATP binding to the activity site(Eriksson, Uhlin et al. 1997). One of the major drawbacks of the RT model is its inability of explaining RNR's activity in the context of subunit olgiomerization. A recently described comprehensive allosteric model by Cooperman not only takes in the basic tenets of the RT model but also qualitatively describes how enzyme activity is regulated by nucleotide dependant oligomerization. In addition to the s- and a-sites, the comprehensive model describes a third allosteric site in Rnr1 known as the hexameric site (h-site). At physiologically significant concentrations, binding of ATP to h-site drives hexamer formation. In this model, dATP is regarded as a universal inhibitor because of inactive tetramer formation. In this proposal we hope to characterize the nucleotide dependant oligomerization state of Rnr1 subunit of the RNR complex using small angle X-ray scattering.

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。子项目及 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。 核糖核苷酸还原酶 (RNR) 催化 DNA 复制所需的脱氧核糖核苷酸库生成过程中的限速步骤。 RNR 对于快速增殖的细胞至关重要，是抗 HSV 和抗癌药物的成功靶点。变构调节是RNR活性调节的重要模式之一。目前描述RNR变构行为的模型主要有两种。 Reichard 和 Thelander 提出的模型（RT 模型）认为，催化位点（c 位点）上的底物结合受结合到特异性位点（s 位点）的给定 dNTP 控制，而全局酶活性取决于ATP 或 dATP 与活性位点结合（Eriksson、Uhlin 等人，1997）。 RT 模型的主要缺点之一是它无法解释 RNR 在亚基低聚化背景下的活性。 Cooperman 最近描述的综合变构模型不仅采用了 RT 模型的基本原理，而且还定性地描述了酶活性如何通过核苷酸依赖性寡聚化进行调节。除了 s 位点和 a 位点之外，综合模型还描述了 Rnr1 中的第三个变构位点，称为六聚位点（h 位点）。在具有生理意义的浓度下，ATP 与 h 位点的结合驱动六聚体的形成。在该模型中，dATP 由于形成无活性的四聚体而被视为通用抑制剂。在本提案中，我们希望使用小角 X 射线散射来表征 RNR 复合物的 Rnr1 亚基的核苷酸依赖性寡聚状态。