Investigating the mechanism of ferritin protection of DNA

研究铁蛋白保护DNA的机制

• 批准号: 8318446
• 负责人: Anna Ruth Arnold
• 金额: $ 4.22万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8318446
• 关键词: Aging; Alzheimer' s Disease; Cell Nucleus; Cells; Charge; Complex; Cytoplasm; DNA; DNA Binding; DNA Damage; DNA Repair; Disease; Electron Spin Resonance Spectroscopy; Electrons; Family; Ferritin; Genome; Goals; Guanine; Human; Hydrogen Peroxide; In Situ; Iron; Malignant Neoplasms; Mediating; Methods; Modeling; Monitor; Oxidants; Oxidation-Reduction; Process; Proteins; Reaction; Reactive Oxygen Species; Spectrum Analysis; System; Techniques; Time; Work; absorption; age related; base; in vivo; oxidation; oxidative DNA damage; transcription factor

DESCRIPTION (provided by applicant): While aging is a complex, multidimensional process that is not yet fully understood, the accumulation of DNA damage has long been recognized as an important factor in aging. The iron storage protein ferritin is a significant player in the defensive strategy of the cell. These proteins deplete ferrous iron and hydrogen peroxide, which can otherwise produce damaging oxygen radicals via the Fenton reaction. While ferritin was traditionally believed to be present solely in the cytoplasm, it recently has been found in cell nuclei, opening up new possibilities for direct DNA protection by ferritin. This study will focus on elucidating the mechanism of ferritin protection of DNA. Dps, a bacterial ferritin whose DNA binding has been extensively studied, will be used as a model for the ferritin family. The ability of DNA to conduct charge through its base stack has been well-studied and DNA charge transfer (CT) processes have been proposed to be biologically relevant in a number of systems such as the activation of redox sensitive transcription factors. In this work, we will determine if the ferritin Dps can protect the genome from a distance by utilizing charge transport through DNA. This will be achieved by combining various spectroscopies with the flash-quench technique, a method to generate a powerful oxidant in situ that is capable of oxidizing DNA. Upon oxidation, the lack of an electron (hole) localizes on guanine, the most easily oxidized base. However, we hypothesize that DNA- bound Dps can become oxidized via DNA CT to fill the hole on the guanine and restore the integrity of the DNA. Transient absorption and electron paramagnetic resonance spectroscopies can monitor guanine radicals and protein oxidation products, and can therefore be used to determine if ferritin can protect DNA from a distance by becoming oxidized in a DNA- mediated process. This work seeks to expand the general mechanisms of protection to include protection from a distance, in the hopes of elucidating one aspect of the dynamic interplay between DNA damage and repair that contributes to aging and age-related disease.

描述（由申请人提供）：虽然衰老是一个复杂的，多方面的过程，尚未完全理解，但DNA损伤的积累长期以来一直被认为是衰老的一个重要因素。铁储存蛋白铁蛋白是细胞防御策略的重要参与者。这些蛋白质消耗亚铁和过氧化氢，否则它们会通过芬顿反应产生有害的氧自由基。虽然铁蛋白传统上被认为仅存在于细胞质中，但最近已在细胞核中发现，为铁蛋白直接保护DNA开辟了新的可能性。本研究将重点阐明铁蛋白保护DNA的机制。Dps是一种细菌铁蛋白，其DNA结合已被广泛研究，将被用作铁蛋白家族的模型。DNA通过其碱基堆叠传导电荷的能力已经得到充分研究，并且DNA电荷转移（CT）过程已经被提出在许多系统中具有生物学相关性，例如氧化还原敏感性转录因子的激活。在这项工作中，我们将确定铁蛋白Dps是否可以通过利用DNA的电荷传输来保护基因组。这将通过将各种光谱学与闪光猝灭技术相结合来实现，闪光猝灭技术是一种原位产生能够氧化DNA的强大氧化剂的方法。在氧化时，缺乏电子（空穴）定位在鸟嘌呤上，鸟嘌呤是最容易氧化的碱基。然而，我们假设DNA结合的Dps可以通过DNA CT被氧化以填充鸟嘌呤上的孔并恢复DNA的完整性。瞬时吸收和电子顺磁共振光谱可以监测鸟嘌呤自由基和蛋白质氧化产物，因此可以用于确定铁蛋白是否可以通过在DNA介导的过程中被氧化而从远处保护DNA。这项工作旨在扩大保护的一般机制，包括从远处保护，希望阐明DNA损伤和修复之间的动态相互作用的一个方面，有助于衰老和年龄相关疾病。