INTERACTIONS OF ANTITUMOR AGENTS WITH NUCLEIC ACIDS

这个项目将探索分子，热力学和生物化学 与有效的抗肿瘤药物的相互作用相关的性质 抗生素m-AMSA和放线菌素D与核酸。 具体地说， 这些研究工作将旨在探索结构和 天然和合成DNA的功能特性， 利用配体的平衡和共价模式的结合 相互作用，并将药物结构与 与复合物形成有关的生物物理参数。 将设计实验以将m-AMSA的结合等温线延伸至 非常低的结合药物浓度，提供了更准确的 描述其化学治疗剂的物理化学性质 效果 热力学，动力学和化学计量测量将是 通过光谱、平衡透析和相分配获得 技术. 相分配方法将特别适用于 在非常低的结合浓度下获得准确的结合等温线 药 光亲和标记技术将扩展到放线菌素 D系统。 共价连接的能力将极大地有助于 靶位点特异性、协同性和/或药物聚类研究 现象。 通过对母体放线菌素D进行化学修饰， 光反应性取代基（叠氮基部分）， 将产生具有平衡结合性质的母体分子 与母体化合物的那些相同（在没有光的情况下）， 具有在光解活化时共价连接的能力。 与放线菌素D共价性质相关的性质- 核酸加合物将通过多种生物化学方法详细检查， 和生物物理技术。 将使用限制性内切酶活性 以监测结合位点特异性和核酸结构 由加合物形成引起的扰动。 同样，几何形状和 确定放线菌素D-DNA加合物的分子取向 在寡核苷酸水平上通过高场核磁共振 谱 这些对m-AMSA和放线菌素D的研究将增加 了解药物结合特性，药物的性质- DNA 复合物和/或加合物，并提供了一种强大的光亲和探针， 进一步定义核酸的结构和功能特性 acids.

This project will explore the molecular, thermodynamic, and biochemical properties associated with the interactions of the potent antitumor antibiotics m-AMSA and actinomycin D with nucleic acids. Specifically, these research efforts will be designed to explore the structural and functional properties of native and synthetic DNAs subsequent to drug binding utilizing both equilibrium and covalent modes of ligand interactions and correlate the relationships of drug structure with the biophysical parameters associated with complex formation. Experiments will be designed to extend the binding isotherms of m-AMSA to very low concentrations of bound drug, providing a more accurate description of the physical chemical nature of its chemotherapeutic effect. Thermodynamic, kinetic, and stoichiometric measurements will be obtained by spectroscopic, equilibrium dialysis, and phase partition techniques. The phase partition method will be particularly useful for obtaining accurate binding isotherms at very low concentrations of bound drug. The technique of photoaffinity labeling will be extended to the actinomycin D system. The capacity for covalent attachment will greatly aid in the study of target site specificities, cooperativity, and/or drug clustering phenomena. Through chemical modification of the parent actinomycin D with a photoreactive substituent (azido moiety), functional analogs of the parent molecule will be generated having equilibrium binding properties identical to those of the parent compound (in the absence of light) yet with the capacity for covalent attachment upon photolytic activation. Properties associated with the covalent nature of the actinomycin D - nucleic acid adduct will be examined in detail by a variety of biochemical and biophysical techniques. Restriction endonuclease activity will be used to monitor binding site specificities and the nucleic acid structural perturbations resulting from adduct formation. Similarly, the geometry and molecular orientation of the actinomycin D - DNA adduct will be determined at the oligonucleotide level by high field nuclear magnetic resonance spectroscopy. These studies on both m-AMSA and actinomycin D will increase the understanding of drug binding properties, the nature of the drug - DNA complex and/or adduct, and provide a powerful photoaffinity probe for further definition of the structural and functional properties of nucleic acids.