BYPASS FIDELITY OF OXIDATIVE DAMAGE LESIONS BY Y-FAMILY DNA POLYMERASE

Y 家族 DNA 聚合酶绕过氧化损伤损伤的保真度

• 批准号: 7955159
• 负责人: DINSHAW J PATEL
• 金额: $ 0.73万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7955159
• 关键词: 4-nitroimidazole; Active Sites; Adopted; Aging; Amino Acids; Architecture; Base Pairing; Bypass; Cardiovascular Diseases; Cells; Computer Retrieval of Information on Scientific Projects Database; Cytosine; DNA; DNA Damage; DNA biosynthesis; DNA-Directed DNA Polymerase; Event; Family; Funding; Genomics; Goals; Grant; Infection; Inflammation; Institution; Lesion; Link; Malignant Neoplasms; Molecular; Molecular Conformation; Mutation; Neurodegenerative Disorders; Oxidative Stress; Polymerase; Reactive Oxygen Species; Recruitment Activity; Research; Research Personnel; Resources; Risk; Shapes; Site; Source; United States National Institutes of Health; adduct; base; oxidative damage; response; spiroiminodihydantoin; structural biology

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. Genomic integrity depends critically on the fidelity and efficiency of DNA replication. High-fidelity DNA polymerases that replicate genomic DNA can stall on certain DNA damage sites, and one or more lesion-bypass Y-family polymerases are recruited to transit the lesion. Such bypass polymerases have a higher error rate and lower processivity on undamaged DNA templates, but can insert a base opposite a lesion site and extend from a damaged base pair in error-free (mutation-avoiding) or error-prone (mutation-generating) manner. Our goal is to understand the molecular mechanisms that define the mutagenic events associated with replication of oxidative damage lesions by bypass polymerases. An increased risk for developing cancer has been linked to oxidative stress due to the overproduction of reactive oxygen species resulting from the response of cells to inflammation and infection. Elevated levels of oxidative damage lesions in genomic DNA have also been associated with neurodegenerative diseases, aging, and cardiovascular disorders. Our crystallographic studies are undertaken on the most prevalent oxidative damage lesions, namely, 8-oxoguanine, the stable ring-opened 5-guanidino-4-nitroimidazole adduct and the fused bicyclic spiroiminodihydantoin adduct, placed in the context of DNA template strands of the active site of Dpo4 Y-family polymerase. Previously, our group uncovered structural and functional features that enable low-fidelity Dpo4 polymerase to achieve predominantly error-free insertion of a cytosine base opposite the 8-oxoguanine (oxoG) lesion. We found of The oxoG lesion adopts an anti conformation within the Dpo4 active site, that is necessary for pairing with dCTP, with the recognition event facilitated by multiple and favorable contacts of Dpo4 amino acid residues with the oxoG. We have also demonstrated that Dpo4 undergoes stepwise translocations throughout the catalytic cycle that are distinct from the corresponding translocation events observed in high-fidelity polymerases. Our efforts should elucidate the common factors that promote error-free or error-prone DNA synthesis opposite and past the oxidative damage lesions of varying size and shape, as well as lesion architecture and preferred conformations.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 基因组完整性严重取决于DNA复制的保真度和效率。复制基因组DNA的高保真DNA聚合酶可以在某些DNA损伤位点停滞不前，并募集一个或多个病变 - 型 - 型 - 型 - 家庭聚合酶以转化病变。这种旁路聚合酶在未损坏的DNA模板上具有较高的错误率和较低的加工率，但可以将基部插入与病变部位相对的基部，并从损坏的碱基对延伸至无误差（避免突变）或容易出现错误（突变产生）方式。 我们的目标是了解定义与旁路聚合酶复制氧化损伤病变相关的诱变事件的分子机制。由于细胞对炎症和感染的反应导致的活性氧过量，导致氧化应激的风险增加与氧化应激有关。基因组DNA中氧化损伤病变的水平升高也与神经退行性疾病，衰老和心血管疾病有关。 我们的晶体学研究是对最普遍的氧化损伤病变进行的，即8-氧气鸟氨酸，稳定的环环5-瓜尼迪诺诺-4-硝基咪唑加合物和融合的bicyclic spiroiminodihydantoin加入，放置在dna模板的上下文中，dna Protym ost y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam y-fam。 以前，我们的小组发现了使低保真DPO4聚合酶的结构和功能特征，以实现对与8-氧气（OXOG）病变相对的胞质碱基的主要无误插入。我们发现OXOG病变在DPO4活性位点中采用了一种抗构象，这对于与DCTP配对是必不可少的，识别事件由DPO4氨基酸残基与OXOG的多个且有利的接触促进了识别事件。 我们还证明，DPO4在整个催化循环中经历逐步易位，这些循环与高保真聚合酶中观察到的相应易位事件不同。我们的努力应阐明促进无错误或易误DNA合成的共同因素，与大小和形状的氧化损伤病变以及病变结构和首选构象相反。