Fluorescent Nucleosides and Oligonucleotides

项目描述（申请人提供）：本项目的目标是设计、合成和实现新的荧光核苷类似物，作为核酸结构、动力学和识别的探针。指导所提出的工作的主要标准是保持与天然核碱基尽可能高的结构相似性，将发射转移到更长的波长，并保持足够的发射量子效率。该项目的具体目标是：(1)设计具有以下特征的“理想”荧光核苷类似物：(i)与天然核碱基的结构高度相似，忠实地模仿其大小和形状，以及杂交和识别特性；（ii）红移吸收光谱，以尽量减少与天然碱基吸收的重叠；（iii）可观的发射量子效率和较长的发射波长（最好在可见范围内）；(2)设计所需核碱基类似物的简明合成方法；(3)研究新核苷的光物理特性；(4)合成和鉴定修饰后的DNA和RNA寡核苷酸；(5)对修饰后的寡核苷酸进行生物物理和光物理表征；(6)在生物物理和发现分析中实现有前途的发射类似物。随着对核酸修饰及其对疾病的影响的日益认识，以及耐药病原体的迅速出现，有必要开发新的工具来有效研究核酸，包括它们的识别特性和外源剂的改变。发射核苷类似物将实施到新的基于荧光的分析。这些检测将有助于：(i)检测在致癌作用中起重要作用的DNA病变（例如8-oxoG）， （ii）在荧光a位点类似物的帮助下发现针对细菌核糖体的新抗生素，（iii）在荧光DIS构建物的帮助下发现新的抗hiv药物，以及（iv）通过发射探针检测蛋白质毒素，如蓖麻毒素，通过检测其去纯化的RNA产物。这些研究将促进对与疾病发展相关的关键生物学过程的基本理解，并将通过促进药物发现对改善人类健康产生长期影响。公共卫生相关性：核酸（DNA和RNA）在生物学中发挥核心作用，因此对疾病的发展和人类健康产生巨大影响。推进有效的基于荧光的工具来探索DNA和RNA的修饰或它们与潜在治疗剂的相互作用，将推进新的诊断方法，并将促进药物的发现。

DESCRIPTION (provided by applicant): The goal of the proposed program is to design, synthesize and implement new fluorescent nucleoside analogs as probes for nucleic acids structure, dynamics and recognition. The main criteria directing the proposed work are to maintain the highest possible structural similarity to the natural nucleobases, to shift the emission to longer wavelengths, and to retain adequate emission quantum efficiency. The specific aims of this project are: (1) To design "ideal" fluorescent nucleoside analog that will possess the following characteristics: (i) A high structural similarity to the native nucleobases to faithfully mimic their size and shape, as well as hybridization and recognition properties, (ii) A red shifted absorption spectrum to minimize overlap with the absorption of the natural bases, (iii) A respectable emission quantum efficiency and a long emission wavelength (preferably in the visible range); (2) To devise concise synthetic approaches to the desired nucleobase analogs; (3) To examine the photophysical characteristics of the new nucleosides; (4) To synthesize and characterize modified DNA and RNA oligonucleotides; (5) To biophysically and photophysically characterize the modified oligonucleotides; and (6) To implement the promising emissive analogs in biophysical and discovery assays. The increased appreciation for nucleic acids modifications and their impact on diseases, as well as the rapid emergence of resistant pathogens, necessitate the development of new tools for the effective study of nucleic acids, including their recognition properties and alteration by exogenous agents. The emissive nucleoside analogs will be implemented into novel fluorescence-based assays. These assays will facilitate: (i) the detection of DNA lesions (e.g., 8-oxoG), that play important roles in carcinogenesis, (ii) the discovery of new antibiotics targeting the bacterial ribosome, assisted by fluorescent A-site analogs, (iii) the discovery of novel anti-HIV agents, assisted by fluorescent DIS constructs, and (iv) the detection of protein toxins, such as ricin, via emissive probes that detect their depurinated RNA products. These investigations will advance the fundamental understanding of key biological processes related to disease development and will have long-term impact on improving human health by facilitating drug discovery. PUBLIC HEALTH RELEVANCE: Nucleic acids (DNA and RNA) play central roles in biology and, as such, have immense impact on the development of diseases and, as such, on human health. Advancing effective fluorescence-based tools for exploring the modification of DNA and RNA or their interactions with potential therapeutic agents will advance new diagnostic approaches and will facilitate drug discovery.