Mass spectrometry Studies on Radical Reactions of DNA

描述(申请人提供)：许多非水解性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。与这一过程有关的各种问题，包括药物在DNA上的结合部位，自由基的形成机制，它与各种DNA位点的可及性，以及由此产生的DNA自由基的去向，都是科学家们正在研究的问题，以促进更好的抗肿瘤和抗病毒药物的合理设计。然而，这一过程的关键部分，即自由基中间体与DNA的反应，仍然没有被探索。尽管药物设计迫切需要控制这种反应的因素的信息，但由于研究这种高活性物种存在严重的实验困难，人们对药物形成的自由基中间体几乎一无所知。我们的目标是学习如何通过结构变化来控制激进弹头的反应性和内在选择性。我们开发了一种基于质谱学的新的实验方法来研究生物相关的自由基反应。该方法包括在FT-ICR质谱仪中将带电基团连接到感兴趣的自由基上以用于操作，其中通过激光诱导的声解吸引入小的中性生物分子。这项提议是一个为期四年的项目的继续，该项目包括：1)购买和建立必要的仪器，2)论证该方法的可行性，3)检查已知系统以显示该方法产生与中性自由基和溶液条件有关的数据，以及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，以促进更好的非水解性DNA切割器的设计。目前建议的工作最重要的领域包括(1)发展更复杂体系的结构/反应性关系，(2)探索不同自由基对寡核苷酸中不同位置的选择性，(3)检测自由基攻击多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，开发提供一般预测能力的反应性范式。(5)这一范例将被用于设计特定目标的激进型弹头和前体药物。抗癌药物设计和机制方面的专家Rick Borch教授(普渡大学药物化学和分子药理学)和生产前体药物的双自由基合成专家Mark Lipton教授将指导研究，并帮助找到将知识融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.