SYNTHESIS & STRUCTURE OF OLIGODEOXYNUCLEOTIDES WITH DEFINED DNA DAMAGE

该项目中的有机化学调查和合成化学共同为该计划其他成员所描述的结构和生物研究提供了一个平台。与过去一样，主要目标之一是合成含有修饰的2‘-脱氧核苷酸的DNA寡聚体，这种寡聚体定位于特定的位置，代表了遗传毒性环境因素造成的损害。许多这些修饰的脱氧核苷酸只知道它们的生物来源，从来没有大量合成过，使广泛的生物学工作成为可能。一个特别贫乏的合成领域是致癌胺，特别是食物诱变剂。在解决了较简单的N_2-DG氨基芳基加合物的合成问题后，将致力于研究C8-DG食品诱变剂加合物的一般方法。第二个研究领域将是将已知的烷基化来昔洛辛应用于寡聚DNA，以便在“后合成”过程中产生N3-烷基化形式的脱氧腺苷和碳脱氧腺苷。这些加合物在不稳定之前，以及以前缺乏任何方法以受控的方式产生它们。将使用核磁共振波谱和计算方法对含有致癌胺加合物的低聚物进行结构研究，并分别对含有N3-烷基化碳水化合物残基的低聚物进行结构研究。这些研究将通过对加合物的研究来确定DNA的局部错位程度，并允许与突变和DNA修复过程相关。第三个研究领域涉及DNA中的化学反应部位(热点)及其与造成损害的制剂的关系。这项研究将试图阐明为什么DNA中的特定核苷序列比其他序列更具反应性。最后，由于双酚A在环境中的普遍存在，任何由其代谢物形成的核苷加合物都将被合成并结合到DNA中进行生物学研究。

The organic chemical investigations and the synthetic chemistry in the Project together provide a platform for the structural and biological research studies described by other members of the program. As in the past, one of the principle objectives is the synthesis of DNA oligomers that contain modified 2'-deoxynucleotides, located site-specifically, and which represent damage caused by genotoxic environmental agents. Many of these modified deoxynucleotides are known only from their biological origin and have never been synthesized in the quantities that make extensive biological work feasible. A specific area of synthesis that has been particularly barren is that of the carcinogenic amines, especially the food mutagens. Now having solved the synthetic problem of the simpler N 2-dG aminoaryl adducts, a significant effort will be made to general methods for the C8-dG food mutagen adducts. A second area of investigation will be to apply the known alkylating lexitropsins to oligomeric DNA so as to generate N3-alkylating forms of deoxyadenosine and carba-deoxyadenosine in a "post-synthetic" process. These adducts pre instability and the previous lack of any method to generate them in a controlled manner. Structural studies using NMR spectroscopy and computational methods will be carried out on oligomers containing carcinogenic amine adducts and separately, on oligomers containing N3-alkylated carba dA residues. These studies will establish the degree of local dislocation of DNA by this study of adduct and allow a correlation with mutagenesis and DNA-repair processes. A third area of investigation concerns the chemically reactive sites in DNA (hot-spots) and their relationship to agents that cause damage. This study will attempt to clarify why specific nucleoside sequences in DNA are more reactive than others. Finally, because of the universal presence of bisphenol-A in the environment, any nucleoside adducts that form from its metabolites will be synthesized and incorporated into DNA for biological studies.