DIYNENE ANTIBIOTICS AND THEIR DNA CLEAVAGE CHEMISTRY

新制癌素发色团，加利车霉素λ 1 I，埃斯波霉素 A1和dynemicin A1是不断增长的类中的代表性成员。 二炔类抗肿瘤抗生素。 这些化合物中的每一种都能够 导致单链和双链DNA在非常低的温度下裂解 在硫醇和分子氧的存在下，将化合物浓度（nM）进行测定。 的 这些化合物的体外和体内活性给人以希望， 通过优先摄取或选择性递送至癌细胞， 例如，通过单克隆抗体的代理，有效的疗法 也许是可能的。 目前正在实施几项这样的战略。 研究，至少有一个是在第二阶段的临床试验， 礼物 更广泛地说，序列选择性DNA的成功设计 基于对有效天然产物的透彻理解， 产品在分子生物学中具有巨大的潜在用途。 在这个新的应用程序中描述的是一套多样但相互关联的 详细了解硫醇的实验方法 加利车霉素的活化、序列识别、结合和反应 用DNA 加利车霉素在二炔类抗肿瘤药物中是引人注目的 抗生素的高效力，高序列选择性和 双链断裂的倾向 的卵裂偏好 药物将被调查的一个进化广泛的DNA组。 这些 优选的位点将在合成中更详细地检查。 使用各种结构和动力学技术，对寡核苷酸进行了分析。 原子转移实验将确保丢失的氢的身份 从DNA骨架中分离出来，并明确地揭示了 小沟里的毒品 这些发现将与结果进行比较 从羟基自由基足迹实验和仔细分析， 裂解片段在高分辨率凝胶上的迁移率 电泳 DNA片段的特征还在于： 化学和光谱手段，以建立各种动力学 将检查药物活化和DNA切割的步骤以确定 整个过程的动态。 最后，NMR实验是 建议通过分子辅助提供更精确的结构信息 建模

The neocarzinostatin chromophore, calicheamicin lambda 1 I, esperamicin A1, and dynemicin A1 are representative members of the growing class of diynene antitumor antibiotics. Each of these compounds is capable of causing single- and double-strand DNA cleavages at very low concentrations (nM) in the presence of thiols and molecular oxygen. The in vitro and in vivo activity of these compounds has given hope that, through preferential uptake or selective delivery to cancer cells, for example, by the agency of a monoclonal antibody, effective therapies might be possible. Several such strategies are currently under investigation, and at least one is in Phase II clinical trials at present. More broadly, the successful design of sequence-selective DNA cleaving agents based on a thorough understanding of effective natural products is of enormous potential utility in molecular biology. Described in this new application is a set of diverse but interlocking experimental approaches to a detailed understanding of the thiol activation, sequence recognition, binding and reaction of calicheamicin with DNA. Calicheamicin is striking among the diynene antitumor antibiotics for its high potency, its high sequence selectively and its propensity for double-strand scissions. The cleavage preferences of the drug will be surveyed for an evolutionary broad group of DNA's. These preferred sites will be examined in greater detail in synthetic oligonucleotides using a variety of structural and kinetic techniques. Atom transfer experiments will secure the identities of hydrogens lost from the DNA backbone and reveal unambiguously the orientation of the drug in the minor groove. These findings will be compared with results from hydroxyl radical footprinting experiments and careful analyses of the mobilities of the cleavage fragments on high resolution gel electrophoresis. The DNA fragments will also be characterized by chemical and spectroscopic means to establish the kinetics of the various steps of drug activation and DNA cleavage will be examined to determining the overall dynamics of the process. Finally, NMR experiments are proposed to give more refined structural information aided by molecular modeling.