DNA SEARCH AND BASE FLIPPING MECHANISMS OF DNA GLYCOSYLASE, MUTM

DNA 糖基化酶 MUTM 的 DNA 搜索和碱基翻转机制

• 批准号: 8361618
• 负责人: GREGORY Lawrence VERDINE
• 金额: $ 0.29万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361618
• 关键词: Bacterial DNA; Base Excision Repairs; Catalysis; DNA; DNA Damage; DNA glycosylase; Disulfides; Funding; Genome; Grant; Guanine; Lesion; Light; National Center for Research Resources; Pathway interactions; Principal Investigator; Proteins; Rare Lesion; Research; Research Infrastructure; Resources; Site; Source; United States National Institutes of Health; base; computer studies; cost; crosslink; nucleobase; structural biology

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. MutM is a bacterial DNA glycosylase that specifically recognizes oxidatively damaged DNA bases and initiates the base excision repair pathway. Given the subtle conformational differences in the lesion base, 8-oxoguanine, and normal DNA base, guanine, and the scarcity of the lesions, a fundamental question arises: how does MutM locate the rare lesion sites among the vast genome? In addition, base flipping, an essential step for DNA glycosylase catalysis, is not well understood, and whether protein is actively promoting base extrusion is currently in debate. Using the disulfide crosslinking strategy, we have covalently trapped ordinarily transient intermediates during the search by MutM for lesions during nucleobase extrusion. These intermediates not only shed light on the mechanism of lesion recognition and catalysis, but have also provided valuable starting points for our computational studies of the base extrusion pathway.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 MutM 是一种细菌 DNA 糖基化酶，可特异性识别氧化损伤的 DNA 碱基并启动碱基切除修复途径。鉴于病变碱基 8-氧鸟嘌呤和正常 DNA 碱基鸟嘌呤的细微构象差异以及病变的稀缺性，出现了一个基本问题：MutM 如何在庞大的基因组中定位罕见的病变位点？此外，碱基翻转这一 DNA 糖基化酶催化的重要步骤尚不清楚，蛋白质是否积极促进碱基挤出目前仍存在争议。使用二硫键交联策略，我们在 MutM 搜索核碱基挤出过程中的损伤过程中共价捕获了通常短暂的中间体。这些中间体不仅揭示了病变识别和催化的机制，而且还为我们对碱基挤出途径的计算研究提供了宝贵的起点。