SYNTHESIS & STRUCTURE OF OLIGODEOXYNUCLEOTIDES WITH DEFINED DNA DAMAGE

本节中描述的合成有机化学构成了 本计划其他成员所描述的研究项目。一个 基本目标是合成一系列修饰的DNA 核苷将被特异性地掺入 使用自动化、固态方法的寡核苷酸。修改后的 选择用于研究的脱氧核苷分为两类。第一 该小组与我们对DNA氧化损伤的研究有关。这些 物质将用于(A)构建亲和层析 用于纯化和分离DNA修复酶(MutM)的底物 和MutY蛋白)来处理氧化损伤，以及(B)研究 这些酶(主要是MutY)在修复中的作用机制 进程。第二组脱氧核苷具有相关的修饰 致癌胺和硝基化合物。它们被细分为两个 类别：(A)与C8-DG加合物有关的类别和(B)上升的类别 通过最终致癌物对N_2位的攻击 脱氧鸟苷。这些定义的加合物将用于建立 原始致癌物产生的致突变谱。此外, 它们应该有助于解决与两国有关的结构性问题 与核苷本身和含有它们的寡聚DNA一起。 为此，将合成13C和15N标记的核苷。 利用新的保护基团进行DNA合成的研究也将 被追捕。这应该允许在其他情况下困难的后合成 将碱基敏感损伤引入DNA。分析研究将 调查新的氧化产物的形成，包括交叉反应 结构尚未表征的连接脱氧核苷二聚体， 并将建立准确、灵敏的氧化产物检测方法 来源于核和线粒体DNA。

The synthetic organic chemistry described in this section forms a basis for the research projects described by other members of the Program. A fundamental objective is the synthesis of a series of modified DNA nucleosides that will be incorporated site-specifically into oligonucleotides using automated, solid-state methods. The modified deoxynucleosides selected for study fall into two classes. The first group is related to our investigations on oxidative DNA damage. These substances will be used (a) to construct affinity chromatography substrates for the purification and isolation of DNA repair enzymes (MutM and MutY proteins) that deal with oxidative lesions and (b) to study the mechanisms of action of these enzymes (principally MutY) in the repair process. The second group of deoxynucleosides have modifications related to carcinogenic amines and nitro compounds. They are subdivided into two classes: (a) those that relate to C8-dG adducts and (b) those that rise by attack of the ultimate carcinogen on the N2-position of deoxyguanosine. These defined adducts will be used to establish the mutagenic spectrum generated by the original carcinogen. In addition, they should aid in the solution of structural problems associated both with the nucleosides themselves and with oligomeric DNA containing them. For these purposes, 13C and 15N-labeled nucleosides will be synthesized. Research on the use of new protecting groups for DNA synthesis also will be pursued. This should allow otherwise difficult post-synthetic introduction of base-sensitive lesions into DNA. Analytical studies will investigate the formation of new oxidation products, including cross- linked deoxynucleoside dimers whose structure has not been characterized, and will establish accurate, sensitive assays for oxidation products derived from nuclear and mitochondrial DNA.