Chemistry and Biology of Malondialdehyde DNA Adducts

丙二醛 DNA 加合物的化学和生物学

• 批准号: 6926428
• 负责人: LAWRENCE J. MARNETT
• 金额: $ 41.4万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6926428
• 关键词: DNA damage; adduct; biochemistry; crosslink; frameshift mutation; malonaldehyde; molecular biology; oxidative stress; physical model

DESCRIPTION (provided by applicant): Malondialdehyde (MDA) and other aldehydic products of oxidative stress represent an important class of endogenous DMA damaging agents universally generated in human beings. These bifunctional electrophiles generate exocyclic adducts to deoxynucleoside bases that prevent Watson-Crick base pairing, block DNA replication, and induce mutations. Our laboratory has defined the chemistry and biology of the pyrimidopurinone adduct to deoxyguanosine, M1dG, which is the major product of DNA damage by MDA and base propenals. Duplex DNA catalyzes a dynamic equilibrium between M1dG and its ring-opened derivative, N2-(3-oxopropenyl)-deoxyguanosine (OPdG). OPdG is less blocking than M1dG to DNA replication and less mutagenic than stable exocyclic analogs of M1dG . We recently discovered that M1dG induces sequence-dependent frameshift mutations in reiterated d(CG)n sequences in E. coli and mammalian cells. We hypothesize that the ability of M1dG to induce frameshift mutations is due to its conversion to OPdG and we propose to test this hypothesis by directly comparing the ability of a series of structural analogs of M1dG and OPdG to induce frameshift mutations in d(CG)n sequences. We recently developed a general synthesis of MDA-DNA adducts in olignucleotides and we propose to use it to explore the chemistry and biology of the other major DNA adduct, N6-(3-oxopropenyl)-deoxyadenosine (OPdA). We will determine the mutation spectrum of OPdA in mammalian cells and we will test the hypothesis that OPdA and other deoxyadenosine products of oxidative stress induce frameshift mutations in reiterated dAn sequences. This type of mutation is commonly observed in critical growth regulating genes that contribute to human cancers and its occurrence has been associated with oxidative stress. MDA-induced DNA-protein cross-links have been reported to exist in cells exposed to oxidants but the identity of these cross-links and the chemistry of their formation is very poorly defined. We propose to explore the chemistry of reaction of M1dG, OPdG, and OPdA with amino acids, peptides, and proteins. Particular attention will be given to the identification of conjugates with DMA-binding proteins such as restriction endonucleases, nucleotide excision repair enzymes, and histones. These experiments will provide critical chemical information with which to evaluate the hypothesis that MDA-induced DNA-protein cross-links are important products of oxidative damage to cells.

描述（由申请方提供）：丙二醛（MDA）和氧化应激的其他代谢产物代表了一类重要的内源性DMA损伤剂，普遍存在于人类中。这些双功能亲电体产生脱氧核苷碱基的环外加合物，阻止沃森-克里克碱基配对，阻断DNA复制，并诱导突变。我们的实验室已经定义了脱氧鸟苷的嘧啶嘌呤酮加合物M1 dG的化学和生物学，M1 dG是MDA和碱丙烯醛损伤DNA的主要产物。双链DNA催化M1 dG和其开环衍生物N2-（3-氧代丙烯基）-脱氧鸟苷（OPdG）之间的动态平衡。OPdG比M1 dG对DNA复制的阻断作用小，比M1 dG的稳定环外类似物的致突变性小。我们最近发现M1 dG在大肠杆菌中诱导重复d（CG）n序列的序列依赖性移码突变。大肠杆菌和哺乳动物细胞。我们假设M1 dG诱导移码突变的能力是由于其转换为OPdG，我们建议通过直接比较M1 dG和OPdG的一系列结构类似物诱导d（CG）n序列移码突变的能力来测试这一假设。我们最近开发了一个一般的合成MDA-DNA加合物的寡核苷酸，我们建议使用它来探索其他主要的DNA加合物，N6-（3-氧代丙烯基）-脱氧腺苷（OPdA）的化学和生物学。我们将确定突变谱OPdA在哺乳动物细胞中，我们将测试的假设，OPdA和其他脱氧腺苷产品的氧化应激诱导移码突变重复dAn序列。这种类型的突变通常在导致人类癌症的关键生长调节基因中观察到，其发生与氧化应激有关。MDA诱导的DNA-蛋白质交联已被报道存在于暴露于氧化剂的细胞中，但这些交联的身份及其形成的化学性质非常不明确。我们建议探索M1 dG，OPdG和OPdA与氨基酸，肽和蛋白质的反应化学。将特别注意鉴定与DMA结合蛋白（如限制性内切核酸酶、核苷酸切除修复酶和组蛋白）的缀合物。这些实验将提供关键的化学信息，以评估MDA诱导的DNA-蛋白质交联是细胞氧化损伤的重要产物的假设。