DNA MEDIATED ELECTRON TRANSFER REACTIONS

说明：本提案寻求继续支持研究， 表征和应用DNA介导的电子转移。 的研究 DNA p-叠层作为电子传递的介质， 了解远程自由基损伤和修复， 通过p-叠层的长距离电荷传输，并且在提供 一种新型诊断工具的基础。 第一批补助金的结果 用金属插层剂作为光诱导供体和受体的周期 已经建立了嵌入式p -堆叠的关键要求 用于快速电子转移。 高效光诱导电子转移 已经证明了金属嵌入剂与 15-mer双链体的末端（通过p-堆叠的41 u间隔），以及 已经开发了溶液和固相方法来制备一系列 金属-寡核苷酸缀合物。 瞬态吸收光谱 也被用于DNA介导的反应，以确定电子 转移中间，并在超快的时间尺度上， (1010 s-1）。 我们现在打算将表征良好的DNA聚合物 (i)确定影响电子转移过程的因素 （二）明确并确定项目的范围; 通过改变嵌入供体的电子转移化学， 受体;和（iii）利用p-堆栈开发新的路线， DNA传感器 我们将描绘出长期的参数 在一系列的电子转移速率的测量反应， 包含拴系金属离子交换器的双工组件， DNA序列长度和构象。 费率也将进行比较 在通过两个单金属化的 寡核苷酸和在一条链上双金属化的双链体。 在 表征电子转移化学，金属插层剂将 相对于核心金属、辅助配体和 立体化学，以确定驱动力和堆积的影响 按价格。 将采用有机插层剂来确定范围 并提供光谱标记。 化学 陷阱也被提出，涉及胸腺嘧啶二聚体位点的修复- 通过光氧化特异性地掺入寡核苷酸中， 铑嵌入剂。 电子转移和交换能量转移 将直接在混合金属-DNA组装体中进行比较， Ru（II）/Os（III）对比Ru（II）/Os（II）。 新型发光材料的研制 提出了一种对碱基对堆积扰动敏感的传感器 使用DNA螺旋作为“导线”。 装配将被构造成 检测碱基对错配并监测堆叠中的变化 与蛋白质结合相关（HaeIII、EcoRI和TATA盒结合 蛋白质），并与抗肿瘤剂顺式- 二胺Pt（II）。 这种电子转移检测策略提供了 为DNA诊断学的发展和 探测溶液中的DNA p堆叠。

DESCRIPTION: This proposal seeks continued support for studies to characterize and apply DNA-mediated electron transfer. The study of the DNA p-stack as a medium for electron transfer is significant in understanding long range radical damage and repair, in characterizing long range charge transport through a p-stack, and in providing the basis for a new class of diagnostic tools. Results in the first grant period using metallointercalators as photoinduced donors and acceptors have established the critical requirement of intercalative p -stacking for fast electron transfer. Efficient photoinduced electron transfer has been demonstrated between metallointercalators tethered to either end of a 15-mer duplex (41u separation through the p-stack), and both solution and solid-phase methods have been developed to prepare a range of metal-oligonucleotide conjugates. Transient absorption spectroscopy has also been used in the DNA-mediated reaction to identify the electron transfer intermediate and, on an ultrafast timescale, to establish rates (1010 s-1). We now intend to apply the well characterized DNA polymer (i) to establish the factors influencing electron transfer processes through p-systems; (ii) to detail and establish the scope for the electron transfer chemistry by varying intercalating donors and acceptors; and (iii) to exploit the p-stack in developing new routes to DNA-based sensors. We will delineate the parameters for the long range reaction in measurements of electron transfer rates on a series of duplex assemblies containing tethered metallontercalators, which vary in DNA sequence, length, and conformation. Rates will also be compared in a duplex constructed through hybridization of two singly metallated oligonucleotides and a duplex doubly metallated on one strand. In characterizing the electron transfer chemistry, metallointercalators will be varied with respect to core metal, ancillary ligands, and stereochemistry to determine the effects of driving force and stacking on rate. Organic intercalators will be employed to establish the scope of this fast reaction and to provide spectroscopic markers. A chemical trap is also proposed, involving the repair of a thymine dimer site- specifically incorporated in an oligonucleotide by photooxidation with a rhodium intercalator. Electron transfer and exchange energy transfer will be compared directly in mixed metal-DNA assemblies constructed with Ru(II)/Os(III) versus Ru(II)/Os(II). The development of new luminescent sensors, sensitive to perturbations in base pair stacking, are proposed using the DNA helix as a "wire". Assemblies will be constructed to detect base pair mismatches and to monitor changes in stacking associated with protein binding (HaeIII, EcoRI, and the TATA-box binding protein) and with coordination of the antitumor agent, cis- diamminePt(II). This electron transfer detection strategy provides a completely new basis for the development of DNA diagnostics and for probing the DNA p-stack in solution.