Structural and Mechanistic Studies of Error-Prone Polymerases

易错聚合酶的结构和机制研究

• 批准号: 7533198
• 负责人: Janice D Pata
• 金额: $ 25.84万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7533198
• 关键词: 2' -deoxycytidine 5' -triphosphate; 8-Oxo-2' -Deoxyguanosine; Address; Anti-Bacterial Agents; Antibiotic Resistance; Bacteria; Binding; Biochemical; Bypass; C-terminal; Cancerous; Cells; Characteristics; Class; Complex; Computing Methodologies; DNA; DNA Damage; DNA Replication Damage; DNA biosynthesis; DNA chemical synthesis; DNA lesion; DNA-Directed DNA Polymerase; Deletion Mutation; Deoxycytidine; Deoxyguanosine; Enzymes; Eukaryotic Cell; Family; Foundations; Genetic; Genome; Goals; Homologous Gene; Human; Investigation; Knowledge; Lead; Lesion; Lung; Malignant Neoplasms; Methods; Modeling; Mutagenesis; Mutation; Nucleotides; Numbers; PCNA gene; Pharmaceutical Preparations; Polymerase; Positioning Attribute; Process; Property; Protein S; Proteins; Public Health; Rate; Relative (related person); Roentgen Rays; Role; Specificity; Staging; Structure; Sulfolobus acidocaldarius; Sulfolobus solfataricus; Testing; Time; Tobacco smoke; Variant; adduct; base; cancer cell; cell growth; preference; prevent; repaired

DESCRIPTION (provided by applicant): The Y-family DNA polymerases help cells tolerate DNA damage by allowing replication to continue opposite lesions in the DNA template. This translesion DNA synthesis can be accurate, preserving the integrity of the genetic information, or it can be error-prone, producing a mutation in the genome even if the DNA damage in the template strand is repaired later. The Y-family polymerases that belong to the DinB subfamily are able to bypass damaged deoxyguanosine bases accurately by incorporating deoxycytidine nucleotides opposite the lesion. The DinB enzymes generally make fewer base-substitution errors than other types of Y-family polymerases, yet they make single-base deletion mutations, where a template base is skipped during replication, at a high rate. We are using the DinB homolog (Dbh) from Sulfolobus acidocaldarius as a model for the DinB class of DNA polymerases. Dbh has been demonstrated to accurately and efficiently bypass DNA damage at deoxyguanosine bases; it displays a strong preference for incorporating deoxycytidine nucleotides even on undamaged DNA; and it generates single-base deletion errors at an exceptionally high rate at specific sequences. The objective of this proposal is to provide a more complete understanding of how structural differences among the various Y-family DNA polymerases give rise to differing lesion-bypass activity and DNA replication fidelity. Our central hypothesis is that the exaggerated mutational specificity and lesion-bypass activity of Dbh will allow us to more easily identify the structural features that influence these activities. The specific aims are (1) to determine how Dbh generates single-base deletion mutations, (2) to elucidate the mechanisms Dbh uses to replicate damaged DNA, and (3) to characterize how Dbh is regulated by interactions with other proteins. We will use a combination of X-ray crystallographic, computational and biochemical approaches to address these issues. These studies will contribute to our understanding of how the Y-family polymerases help cells tolerate DNA damage and also how they introduce mutations into the genome. PUBLIC HEALTH RELEVANCE: An accumulation of multiple mutations in human cells can lead to cancerous cell growth, while mutations in bacteria can lead to antibiotic resistance. The Y-family DNA polymerases appear to be responsible for many of the mutations produced in both prokaryotic and eukaryotic cells. Inhibiting these polymerases, at appropriate times, could be a useful way to prevent cancers from progressing or to increase the efficacy of antibacterial drug treatments.

描述（由申请人提供）：Y家族DNA聚合酶通过允许复制继续DNA模板中的相反损伤来帮助细胞耐受DNA损伤。这种跨损伤 DNA 合成可以是准确的，保留遗传信息的完整性，也可以是容易出错的，即使模板链中的 DNA 损伤稍后得到修复，也会在基因组中产生突变。属于 DinB 亚家族的 Y 家族聚合酶能够通过在病变对面掺入脱氧胞苷核苷酸来准确绕过受损的脱氧鸟苷碱基。 DinB 酶通常比其他类型的 Y 家族聚合酶产生更少的碱基取代错误，但它们会产生单碱基缺失突变，即复制过程中模板碱基被跳过的概率很高。我们使用来自酸热硫化叶菌的 DinB 同源物 (Dbh) 作为 DinB 类 DNA 聚合酶的模型。 Dbh 已被证明能够准确有效地绕过脱氧鸟苷碱基处的 DNA 损伤；即使在未受损的 DNA 上，它也表现出对掺入脱氧胞苷核苷酸的强烈偏好；它在特定序列上以极高的速率产生单碱基缺失错误。该提案的目的是更全面地了解各种 Y 家族 DNA 聚合酶之间的结构差异如何导致不同的病变旁路活性和 DNA 复制保真度。我们的中心假设是，Dbh 夸大的突变特异性和病变绕过活性将使我们能够更容易地识别影响这些活性的结构特征。具体目标是 (1) 确定 Dbh 如何产生单碱基缺失突变，(2) 阐明 Dbh 用于复制受损 DNA 的机制，以及 (3) 表征 Dbh 如何通过与其他蛋白质的相互作用进行调节。我们将结合使用 X 射线晶体学、计算和生物化学方法来解决这些问题。这些研究将有助于我们了解 Y 家族聚合酶如何帮助细胞耐受 DNA 损伤以及它们如何将突变引入基因组。公共卫生相关性：人类细胞中多种突变的积累可能导致癌细胞生长，而细菌的突变可能导致抗生素耐药性。 Y 家族 DNA 聚合酶似乎是原核和真核细胞中产生的许多突变的原因。在适当的时间抑制这些聚合酶可能是预防癌症进展或提高抗菌药物治疗功效的有效方法。