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

低聚糖是许多抗肿瘤抗生素的成分，可以结合 转移到DNA上。然而，人们对该组织的作用知之甚少 任何DNA结合剂中的低聚糖。建议的长期目标是 研究是为了了解寡糖是如何在三个特定的 抗肿瘤抗生素-Calicheamicin Gamma1，Chroomycin A3，和 环霉素0-参与DNA结合。最终目标是使用 这种对设计更简单的碳水化合物基DNA结合剂的理解 治疗活动。拟议研究的具体目标是： 一、了解低聚糖-芳基尾巴的作用 加利他米星GAMMA1 A)合成类似物，其中关键结构特征为 低聚糖-芳基尾巴(例如N-O键、硫代苯甲酸 环)已被更改； B)评估结构变化对DNA结合的影响 和特异性使用足迹和亲和力切割； C)开发Calicheamicin-DNA复合体的结构模型 使用核磁共振；重点是关联溶液构象 低聚糖到结合的构象和识别接触 DNA。 了解糖在色霉素A3中的作用 A)确定C-D-E三糖的哪些糖是 形成二聚体金属络合物所需的最低限度 解决方案；为此，UV/VIS、CD和核磁共振光谱学将 用于表征降解形成的金属络合物 CRA3产品； B)确定溶液中二聚体的稳定性与DNA的关系 结合亲和力；为此， 将使用UV/Vis对CRA3的降解产物进行评估 光谱学； C)合成一种简化的CRA3类似物，只含有 发色团和C-D-E三糖，并评价其能力 二聚体并与DNA结合。 三、了解环糊霉素0 A)合成环糊霉素0； B)使用一维核磁共振确定环拉霉素0是否与DNA结合 用于监测添加药物后的DNA亚胺质子的光谱学。 如果指示结合，三糖在DNA中的作用 将对绑定进行调查。

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.