Nucleotide and Base Excision Repair

核苷酸和碱基切除修复

• 批准号: 7152380
• 负责人: TOM E. ELLENBERGER
• 金额: $ 5.27万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7152380
• 关键词: DNA; enzymes; nucleotides; proteins

The Project (Nucleotide Excision Repair and Base Excision Repair) focuses on understanding the interactions of key proteins with DNA substrates and partner proteins critical for functional DNA excision repair complexes. Our goal is to leverage structural and biochemical studies of the repair endonuclease ERCC1-XPF and of DNA ligase to illuminate the coordination of the multi-step reaction pathways that comprise Nucleotide Excision Repair (NER) and the completion of B_ase Excision Repair (NER). Defects in DNA excision repair proteins and pathways result in increased rates of mutation, chromosomal breakage, and an increased incidence of cancers. Distortions of the helical structure of DNA are specifically recognized by repair enzymes and can be read out in a way that does not depend on the chemical identity of the damage. This generalized strategy enables one enzyme to initiate the repair of a variety of lesions in DNA. Moreover, interactions with other DNA binding and repair proteins provide additional biological specificity and contribute to the efficiency of repair. Although the enzymatic activities constituting the basic NER and BER pathways are known, it remains to be determined how these activities are coordinated into a multi-step reaction pathway by the physical interactions within enzyme-DNA complexes catalyzing the excision repair of DNA damage. Structural analyses of the relevant enzyme-DNA complexes will reveal distinct conformational states of the enzymes and their DNA substrates corresponding to different steps of the repair reaction. Low-resolution structures and conformations derived from x-ray scattering in solution will complement high-resolution images of the repair complexes that can be crystallized. In this way, the dynamic assembly and disassembly of multi-protein complexes catalyzing DNA repair will be characterized. We propose to test and develop these hypotheses by investigating specific excision repair components as follows: 1) Catalytic Substrate specificity of XPF-ERCC1, and related DNA structure-specific nucleases; 2) Damage senses by XPA that recruits XPFERCC1 to NER complexes; 3) Catalytic selectivity of DNA ligases; Nick-sensing and DNA repair; 4) Interactions of DNA Ligase I with DNA sliding clamps; and 5) Interactions of ligase I with the clamp loaders.

该项目（核苷酸切除修复和碱基切除修复）的重点是 了解关键蛋白质与DNA底物和伴侣蛋白质的相互作用， DNA切除修复复合物。我们的目标是利用修复的结构和生物化学研究 内切酶ERCC 1-XPF和DNA连接酶，以阐明多步反应的协调 包括核苷酸切除修复（NER）和B_ase切除修复的完成的途径 （NER）。DNA切除修复蛋白和途径的缺陷导致突变率增加， 染色体断裂和癌症发病率增加。DNA螺旋结构的扭曲 被修复酶特异性识别，并且可以以不依赖于 损伤的化学特性。这种普遍的策略使一种酶能够启动修复一个细胞的功能。 DNA中的各种损伤。此外，与其他DNA结合和修复蛋白的相互作用提供了 额外的生物特异性，并有助于修复的效率。虽然酶活性 构成基本的NER和BER途径是已知的，仍然有待确定这些活动如何 通过酶-DNA之间的物理相互作用， 复合物催化DNA损伤的切除修复。相关酶-DNA的结构分析 复合物将揭示酶及其DNA底物的不同构象状态， 修复反应的不同步骤。X射线低分辨结构和构象 溶液中的散射将补充修复复合物的高分辨率图像， 结晶通过这种方式，催化DNA的多蛋白质复合物的动态组装和拆卸 修复将被描述。我们建议通过调查具体的研究来测试和发展这些假设。 切除修复组分如下：1）XPF-ERCC 1和相关DNA的催化底物特异性 结构特异性核酸酶; 2）通过XPA将XPFERCC 1募集到NER复合物的损伤感觉; 3）DNA连接酶的催化选择性;切口感测和DNA修复; 4）DNA连接酶I与DNA滑动夹的相互作用;以及5）连接酶I与夹加载器的相互作用。