SUGARS IN DNA BINDERS--STRUCTURE, FUNCTION, AND DESIGN

寡聚体是许多抗肿瘤抗生素的成分， 到DNA 然而，人们对它的作用知之甚少。 任何DNA结合剂中的寡糖。 拟议的长期目标 研究是为了了解三种特定的寡糖是如何 抗肿瘤抗生素-加利车霉素γ 1，色霉素A3，和 Ciclamycin 0 -参与DNA结合。 最终目标是利用 这种理解设计更简单的基于碳水化合物的DNA结合剂， 治疗活性。 拟议研究的具体目标是： I.了解寡糖-芳基尾的作用 加利车霉素γ 1 a）合成类似物，其中所述化合物的关键结构特征 寡糖-芳基尾（例如，N-O键硫代苯甲酸酯 环）已更改; B）评估结构变化对DNA结合的影响 和亲和切割的特异性; c）开发卡奇霉素-DNA复合物的结构模型 使用NMR;重点是将溶液构象与 寡糖结合的构象，并确定接触， DNA 二. 了解糖在色霉素A3中的作用 a）为了确定C-D-E三糖中的哪些糖是 最低限度地需要形成二聚体金属络合物， 溶液;为此，UV/维斯、CD和NMR光谱将 用于表征降解形成的金属络合物 CRA 3产品; B）确定溶液中二聚体稳定性与DNA的关系 结合亲和力;为此， 将使用UV/维斯评价CRA 3的降解产物 光谱学; c）合成仅含有CRA 3的简化类似物， 和C-D-E三糖，并评估其对 二聚化并与DNA结合。 三.了解环霉素0 a）环拉霉素0的合成; B）使用1-D NMR确定环拉霉素0是否与DNA结合 在添加药物后，使用光谱学监测DNA亚氨基质子。 如果表明结合，则三糖在DNA中的作用 绑定将被调查。

Oligosaccharides are components of many antitumor antibiotics that bind to DNA. However, very little is known about the role of the oligosaccharides in any DNA binders. The long-term goal of the proposed research is to understand how the oligosaccharides in three specific antitumor antibiotics - calicheamicin gamma1, chromomycin A3, and ciclamycin 0 - are involved in DNA binding. The ultimate goal is to use this understanding to design simpler carbohydrate-based DNA binders with therapeutic activity. The specific aims of the proposed research are: I. Understanding the role of the oligosaccharide-aryl tail of calicheamicin gamma1 a) To synthesize analogues in which key structural features of the oligosaccharide-aryl tail (e.g., the N-O bond, the thiobenzoate ring) have been altered; b) To assess the effects of the structural changes on DNA binding and specificity using footprinting and affinity cleavage; c) to develop a structural model for the calicheamicin-DNA complex using NMR; the point is to relate the solution conformation of the oligosaccharide to the bound conformation and identify contacts to the DNA. II. Understanding the role of sugars in chromomycin A3 a) To determine which sugars of the C-D-E trisaccharide are minimally required for formation of a dimer metal complex in solution; to this end, UV/VIS, CD, and NMR spectroscopy will be used to characterize the metal complexes formed by degradation products of CRA3; b) To determine how dimer stability in solution relates to DNA binding affinity; to this end, the DNA binding affinity of the degradation products of CRA3 will be evaluated using UV/VIS spectroscopy; c) To synthesize a simplified analogue of CRA3 containing only the chromophore and C-D-E trisaccharide and evaluate its ability to dimerize and bind to DNA. III. Understanding ciclamycin 0 a) To synthesize ciclamycin 0; b) To determine whether ciclamycin 0 binds to DNA using 1-D NMR spectroscopy to monitor DNA imino protons upon addition of drug. If binding is indicated, the role of the trisaccharide in DNA binding will be investigated.