DNA Charge Transport Chemistry & Biology

DNA电荷传输化学

• 批准号: 7869629
• 负责人: JACQUELINE K BARTON
• 金额: $ 6.2万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-17 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7869629
• 关键词: Archaea; Base Excision Repairs; Biological; Biological Assay; Biology; Cancerous; Cells; Charge; Chemistry; Complex; DNA; DNA Binding; DNA Damage; DNA Repair; DNA-Binding Proteins; Detection; Distant; Electrochemistry; Electron Transport; Electrons; Enzymes; Escherichia coli; Goals; Guanine; Hela Cells; Homologous Gene; Human; In Vitro; Injection of therapeutic agent; Lesion; Ligands; Malignant Neoplasms; Mediating; Mitochondria; Mitochondrial DNA; Mutation; Oxidants; Oxidative Stress; Predisposition; Process; Proteins; Rhodium; Role; Series; Signal Transduction; Site; Spectrum Analysis; Testing; Transcription Coactivator; Transcription Initiation; Transcriptional Regulation; absorption; analog; base; cyclopropylamine; endonuclease III; genetic regulatory protein; mitochondrial DNA mutation; mutant; oxidation; oxidative DNA damage; oxidative damage; public health relevance; repair enzyme; repaired; research study

DESCRIPTION (provided by applicant): This proposal aims to characterize the chemistry and biology associated with DNA-mediated charge transport (CT). Specifically, roles for DNA CT in how DNA is damaged and repaired under oxidative stress will be explored. Experiments are proposed to examine oxidative DNA damage at long range as well as DNA-mediated signaling to regulatory proteins. We will examine the distance range over which oxidative damage is funneled to a control sequence in mitochondria using rhodium photooxidants to generate damage at distant sites. Mitochondrial DNA mutations and their correlations with cancers will also be determined. We will further delineate the role of DNA CT in DNA damage detection by base excision repair (BER) enzymes that contain 4Fe-4S clusters. We will prepare a series of BER enzyme mutants to characterize the path for DNA/protein CT. CT will be probed using DNA electrochemistry, EPR, transient absorption spectroscopy and AFM. In vitro protein oxidations by guanine radicals in DNA will be generated by hole injection from tethered metallointercalators. Biological assays of repair in E. coli will test how effectively mutants of two BER enzymes, MutY and Endonuclease III (EndoIII), cooperate in detecting base lesions. Correlations will be drawn between this biological helper function, DNA/protein CT studies, and cancer predispositions in human MutY homologues. DNA-mediated CT for transcriptional regulation will also be examined in soxR, a transcriptional activator from E. coli containing an Fe-S cluster. We will test the initiation of transcription from a distance through long range oxidation of DNA-bound soxR using tethered photooxidants. Paralleling these CT studies with DNA-bound proteins, we will construct DNA assemblies containing tethered metallointercalators, cyclometallated complexes of Ir and Re(CO) diimine complexes, to characterize DNA-mediated reduction chemistry versus long range DNA- mediated oxidations. PUBLIC HEALTH RELEVANCE: This proposal is focused on examining chemically how DNA is damaged and repaired when cells undergo oxidative stress. Damaged DNA, if unrepaired, leads to cancerous transformations. Understanding both the damage and repair process is critical to evaluating cancer predispositions.

描述（由申请人提供）：本提案旨在描述与dna介导的电荷传输（CT）相关的化学和生物学。具体来说，DNA CT在氧化应激下DNA损伤和修复中的作用将被探讨。实验提出了检查氧化DNA损伤在远距离以及DNA介导的信号传导到调节蛋白。我们将研究使用铑光氧化剂在远处产生损伤的线粒体中，氧化损伤被引导到控制序列的距离范围。线粒体DNA突变及其与癌症的关系也将被确定。我们将进一步描述DNA CT在含有4Fe-4S簇的碱基切除修复（BER）酶检测DNA损伤中的作用。我们将制备一系列BER酶突变体来表征DNA/蛋白CT的路径。CT将使用DNA电化学，EPR，瞬态吸收光谱和AFM进行探测。栓系金属插入体的孔注射可引起DNA中鸟嘌呤自由基的体外蛋白氧化。大肠杆菌修复的生物学试验将测试两种BER酶（MutY和EndoIII）的突变体如何有效地协同检测碱基损伤。这种生物辅助功能、DNA/蛋白质CT研究和人类MutY同源物的癌症易感性之间的相关性将被绘制出来。dna介导的CT转录调控也将在soxR中进行检测，soxR是一种来自含有Fe-S簇的大肠杆菌的转录激活剂。我们将通过使用系缚光氧化剂对dna结合的soxR进行长距离氧化，从远处测试转录的起始。将这些CT研究与DNA结合蛋白相结合，我们将构建包含栓系金属插入物的DNA组装体，Ir和Re（CO）二亚胺复合物的环金属化复合物，以表征DNA介导的还原化学与远程DNA介导的氧化。公共卫生相关性：本提案的重点是研究细胞氧化应激时DNA是如何受损和修复的化学方法。受损的DNA如果不修复，就会导致癌变。了解损伤和修复过程对于评估癌症易感性至关重要。