INTERACTIONS OF ANTITUMOR AGENTS WITH NUCLEIC ACIDS

本项目将探索分子、热力学和生物化学 与强效抗肿瘤药物相互作用相关的性质 抗菌素m-AMSA和放线菌素D与核酸。具体来说， 这些研究工作将旨在探索结构和 药物作用后天然和合成DNA的功能特性 利用配基的平衡和共价模式结合 药物结构与药物的相互作用和相互关系 与复杂地层相关的生物物理参数。 将设计实验将m-AMSA的结合等温线扩展到 极低浓度的结合药物，提供了更准确的 关于其化疗的物理化学性质的描述 效果。热力学、动力学和化学计量测量将是 通过光谱、平衡渗析和相分配获得 技巧。相分割方法对以下方面特别有用 在很低的结合浓度下获得准确的结合等温线 毒品。 光亲和标记技术将推广到放线菌素 D系统。共价连接的能力将极大地帮助 靶点特异性、协同性和/或药物聚集性的研究 现象。通过对亲本放线菌素D进行化学修饰 一种光反应取代基(叠氮部分)，其功能类似物 将产生具有平衡结合性质的母体分子 与母体化合物相同(在无光的情况下) 在光解激活时具有共价连接的能力。 与放线菌素D-的共价性质有关的性质 核酸加合物将通过各种生化手段进行详细检测 和生物物理技术。将使用限制性内切酶活性 以监测结合位点的特异性和核酸结构 由加合物形成引起的扰动。类似地，几何体和 放线菌素D-DNA加合物的分子取向将被确定 高场核磁共振在寡核苷酸水平上的应用 光谱学。 M-AMSA和放线菌素D的这些研究将增加 了解药物结合特性、药物-DNA的性质 络合物和/或加合物，并提供强大的光亲和探针 进一步定义原子核的结构和功能性质 酸。

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.