Mass spectrometry Studies on Radical Reactions of DNA

描述（由申请人提供）：许多非水解DNA裂解剂的作用被认为是基于从DNA中的脱氧核糖中提取氢原子的反应性苯基。与此过程有关的各种问题，包括药物在DNA上的结合位点，自由基形成的机制，其对各种DNA位点的可及性，以及所产生的DNA自由基的命运，正在由科学家解决，以推进更好的抗肿瘤和抗病毒药物的合理设计。然而，这个过程的关键部分，自由基中间体与DNA的反应，仍然没有被探索。虽然控制这种反应的因素的信息是迫切需要的药物设计，几乎没有什么是已知的自由基中间体形成的药物，因为严重的实验困难，在研究这样的高活性物种。我们的目标是了解如何控制的反应性和内在的选择性的激进弹头的结构变化。我们已经开发了一种新的实验方法的基础上质谱研究生物相关的自由基反应。该方法包括将带电基团连接到感兴趣的自由基上，以在FT-ICR质谱仪中进行操作，其中通过激光诱导的声学解吸引入小的中性生物分子。该提案是一个为期四年的项目的延续，该项目涉及1）购买和安装必要的仪器，2）演示该方法的可行性，3）检查已知系统，以表明该方法产生与中性自由基和溶液条件相关的数据，和4）收集动力学反应性数据，以提供几种新的结构/反应性关系，用于改进更好的非水解DNA切割剂的设计。目前提出的工作中最重要的领域包括（1）为更复杂的系统开发结构/反应性关系，（2）探索不同自由基对寡核苷酸中不同位点的选择性，（3）检查自由基攻击肽的倾向以模拟蛋白质损伤，以及（4）基于上述研究中获得的见解，开发一种反应性范例，提供一般的预测能力。(5)这一范例将用于设计针对特定目标的激进弹头和前药。Rick Borch教授（药物化学和分子药理学，普渡大学），癌症药物设计和机制专家，Mark Lipton（有机化学，普渡大学），双自由基生产前药合成专家，将指导研究并帮助找到将知识纳入新药设计和测试的最佳方法。

DESCRIPTION (provided by applicant): The action of many non-hydrolytic DNA cleaving agents is believed to be based on reactive phenyl radicals that abstract hydrogen atoms from deoxyribose in DNA. Various issues relating to this process, including the drug's binding site on DNA, the mechanism of radical formation, its accessibility to various DNA sites, and the fate of the resulting DNA radicals, are being addressed by scientists to advance the rational design of better antitumor and antiviral drugs. However, the key part of the process, the reaction of the radical intermediate with DNA, remains unexplored. Although information on the factors that control this reaction is critically needed for drug design, nearly nothing is known about the radical intermediates formed from drugs because of severe experimental difficulties in studying such highly reactive species. Our goal is to learn how to control the reactivity and intrinsic selectivity of a radical warhead by structural changes. We have developed a novel experimental approach based on mass spectrometry to study biologically relevant radical reactions. The method involves attaching a charged group to a radical of interest for manipulation in an FT-ICR mass spectrometer wherein small neutral biomolecules are introduced by laser-induced acoustic desorption. This proposal presents a continuation of a four-year project that involved 1) purchase and set-up of the necessary instrumentation, 2) demonstration of the feasibility of the approach, 3) examination of known systems to show that the method yields data relevant to neutral radicals and solution conditions, and 4) collection of kinetic reactivity data to provide several novel structure/reactivity relationships for advancement of the design of better non-hydrolytic DNA cleavers. The most important areas of the currently proposed work include (1) development of structure/reactivity relationships for more complex systems, (2) exploration of the selectivity of different radicals toward different sites in oligonucleotides, (3) examination of the propensity of the radicals to attack peptides to model protein damage, and (4) based on the insights gained in the above studies, development of a reactivity paradigm that provides general predictive power. (5) This paradigm will be used to design target-specific radical warheads and prodrugs. Professors Rick Borch (Medicinal Chemistry and Molecular Pharmacology, Purdue), a specialist in cancer drug design and mechanisms,and Mark Lipton (Organic Chemistry, Purdue), an expert in synthesis of biradical producing prodrugs, will guide the research and help in finding the best way to incorporate knowledge into the design and testing of novel drugs.