DNA Charge Transport Chemistry & Biology

DNA电荷传输化学

• 批准号: 7742610
• 负责人: JACQUELINE K BARTON
• 金额: $ 37.49万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7742610
• 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特性。具体地说，DNA CT在DNA在氧化应激下如何损伤和修复中的作用将被探索。有人建议进行实验，以检查远距离的DNA氧化损伤以及DNA介导的调节蛋白信号。我们将研究氧化损伤与线粒体中的控制序列的距离范围，该距离范围使用荧光光氧化剂在远端位置产生损伤。线粒体DNA突变及其与癌症的相关性也将被确定。我们将进一步阐明DNA CT在通过含有4Fe-4S簇的碱基切除修复(BER)酶检测DNA损伤中的作用。我们将准备一系列BER酶突变体来表征DNA/蛋白质CT的途径。CT将使用DNA电化学、EPR、瞬时吸收光谱和原子力显微镜进行探测。在体外，DNA中鸟嘌呤自由基对蛋白质的氧化作用是通过金属嵌入体上的空穴注入产生的。在大肠杆菌中修复的生物测试将测试两种BER酶的突变体，MutY和内切酶III(EndoIII)，在检测碱基损伤方面如何有效地合作。在人类MutY同源物中，这种生物辅助功能、DNA/蛋白质CT研究和癌症易感性之间的相关性将被得出。DNA介导的CT转录调控也将在SoxR中进行检测，SoxR是一种来自大肠杆菌的转录激活剂，含有Fe-S簇。我们将使用系留光氧化剂通过DNA结合的soxR的远程氧化来测试转录的启动。与DNA结合蛋白的CT研究平行，我们将构建包含系留金属嵌入物、Ir和Re(CO)二亚胺配合物的环化金属配合物的DNA组合体，以表征DNA介导的还原化学与DNA介导的远程氧化。与公共健康相关：这项建议的重点是从化学角度研究当细胞遭受氧化应激时DNA是如何受损和修复的。受损的DNA如果得不到修复，就会导致癌变。了解损伤和修复过程对于评估癌症的易感性至关重要。