STRUCTURAL STUDY OF THE DNA DECAMER DUPLEXES CONTAINING DOUBLE T-G MISMATCHES

含双T-G不匹配的DNA十聚体双链体的结构研究

• 批准号: 8168636
• 负责人: IHEE HYOTCHERL
• 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/8168636
• 关键词: Affect; Affinity; Agreement; Binding; Computer Retrieval of Information on Scientific Projects Database; DNA; DNA photoproducts; Data; Funding; Goals; Grant; Institution; Lesion; Measurement; Nature; Nucleotide Excision Repair; Pathway interactions; Process; Proteins; Pyrimidine Dimers; Research; Research Personnel; Resources; Roentgen Rays; Solutions; Source; Structure; System; Ultraviolet Rays; United States National Institutes of Health; cytotoxic; repair enzyme; repaired; ultraviolet irradiation

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. Understanding the mechanism responsible for the DNA photodamage and the repair process would be a first step toward finding a solution to reduce the photodamage and enhance the repair. The cis-syn cyclobutane pyrimidine dimer (CPD) is one of the major classes of cytotoxic, mutagenic and carcinogenic DNA photoproducts induced by UV light. Though CPD formation due to the UV irradiation occurs quite frequently, CPD lesion is poorly recognized by repair enzyme XPC-hHR23B which is the primary damage recognition protein of the nucleotide excision repair (NER) pathway. Intriguingly, CPD/GG duplex represents unusually severe helical distortion due to the presence of double T-G mismatches, and XPC-hHR23B protein has a considerably higher binding affinity for CPD/GG duplex compared with the usual CPD lesion (CPD/TT). Therefore it is of importance to understand in which manner the target substrate for this protein is formed and how the T-G mismatches affect this process. Toward this goal we conducted wide-angle X-ray scattering (WAXS) measurement to investigate structural change of DNA duplex under CPD formation, double T-G mismatches and interaction with XPC-hHR23B protein in solution. Since X-ray solution scattering provides rich information about the structure, we expected to see the essential difference between damaged and undamaged DNA and between normal and mismatched DNA. We successfully obtained high-quality WAXS data from the DNA systems, with the experimental data in very good agreement with theoretical prediction. Further analysis to solve the nature of damaging and repairing process is still ongoing.

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。 了解 DNA 光损伤和修复过程的机制将是寻找减少光损伤和增强修复的解决方案的第一步。顺式-顺式环丁烷嘧啶二聚体 (CPD) 是紫外线诱导的主要一类细胞毒性、诱变性和致癌性 DNA 光产物。尽管由于紫外线照射而导致的 CPD 形成相当频繁，但修复酶 XPC-hHR23B 很难识别 CPD 病变，而修复酶 XPC-hHR23B 是核苷酸切除修复 (NER) 途径的主要损伤识别蛋白。有趣的是，由于双 T-G 错配的存在，CPD/GG 双链体代表异常严重的螺旋畸变，并且与常见的 CPD 损伤 (CPD/TT) 相比，XPC-hHR23B 蛋白对 CPD/GG 双链体具有相当高的结合亲和力。因此，了解该蛋白质的靶底物以何种方式形成以及 T-G 错配如何影响该过程非常重要。为了实现这一目标，我们进行了广角 X 射线散射 (WAXS) 测量，以研究 CPD 形成下 DNA 双链体的结构变化、双 T-G 错配以及与溶液中 XPC-hHR23B 蛋白的相互作用。由于 X 射线溶液散射提供了有关结构的丰富信息，因此我们期望看到受损和未受损 DNA 之间以及正常 DNA 和不匹配 DNA 之间的本质区别。我们成功地从DNA系统中获得了高质量的WAXS数据，实验数据与理论预测非常吻合。进一步分析解决损坏性质和修复过程仍在进行中。