DIYNENE ANTIBIOTICS AND THEIR DNA CLEAVAGE CHEMISTRY

新卡拉抑素发色团，Calicheamicin lambda 1I，esperamicin A1和Dynemicin A1是不断增长的 二芳烯类抗肿瘤抗生素。这些化合物中的每一个都能够 导致单链和双链DNA在非常低的水平上切割 硫醇和分子氧存在时的浓度(NM)。这个 这些化合物的体外和体内活性给人们带来了希望， 通过优先摄取或选择性递送到癌细胞， 例如，通过一种单克隆抗体的代理，有效的治疗 也许是可能的。目前有几个这样的战略正在实施 研究，至少有一项正在进行第二阶段临床试验 现在时。更广泛地说，序列选择性DNA的成功设计 基于对有效天然物质的透彻理解的裂解剂 产品在分子生物学领域具有巨大的潜在应用价值。 在这个新的应用程序中描述的是一组不同但相互关联的 详细了解硫醇的实验方法 Calicheamicin的活化、序列识别、结合和反应 有DNA的。在二炔类抗肿瘤药物中，Calicheamicin引人注目 抗生素的高效性、高选择性和高顺序性 有双链断裂倾向。人的卵裂偏好 药物将为进化中的广泛DNA群体进行调查。 优先选择的地点将在合成的 使用各种结构和动力学技术的寡核苷酸。 原子转移实验将确保丢失的氢的身份 并毫不含糊地揭示了 小阴沟里的毒品。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 裂解片段在高分辨凝胶上的迁移率 电泳法。DNA片段还将被表征为 用化学和光谱方法建立各种分子的动力学 药物活化和DNA裂解的步骤将被检查以确定 这一过程的总体动态。最后，核磁共振实验是 建议在分子辅助下提供更精细的结构信息 模特儿。

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.