DNA Charge Transport Chemistry & Biology

项目摘要/摘要 这项提议旨在描述与DNA相关的化学和生物学特性。 电荷传输(CT)。具体地说，DNA CT在DNA损伤和修复中的作用 本课程将探讨氧化应激。有人提议用实验来检测氧化dna损伤。 范围以及DNA介导的信号传递到调节蛋白。我们将检查距离范围 在这个过程中，氧化损伤被漏斗到线粒体的控制序列中，使用Rh 光氧化剂在遥远的地方产生损害。线粒体DNA突变及其意义 与癌症的相关性也将得到确定。我们将进一步描述DNA CT在DNA中的作用 通过含有4Fe-4S簇的碱基切除修复(BER)酶进行损伤检测。我们会做好准备 一系列BER酶突变体来表征DNA/蛋白质CT的路径。CT将使用以下工具进行探测 DNA电化学、电子顺磁共振、瞬时吸收光谱和原子力显微镜。体外蛋白质氧化作用 DNA中的自由基将通过金属嵌入剂的空穴注入而产生。 在大肠杆菌中修复的生物测试将测试两种BER酶MutY和MutY的突变体的有效性 核酸内切酶III(EndoIII)，在检测碱基损伤时协同工作。它们之间的关联将被绘制成 这种生物辅助功能、DNA/蛋白质CT研究和人类MutY的癌症易感性 同源同源。DNA介导的转录调节CT也将在soxR，a 含有铁-S簇的大肠杆菌转录激活剂。我们将测试启动 利用拴系法通过DNA结合SoxR的远程氧化实现远距离转录 光氧化剂。与DNA结合蛋白的CT研究平行，我们将构建DNA 含系留金属插层剂的组装体、Ir和Re(CO)的环金属络合物 二亚胺络合物，以表征DNA介导的还原化学与远程DNA- 介导的氧化作用。

Project Summary/Abstract 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.