Fluorescent Nucleosides and Oligonucleotides

描述（由申请人提供）：拟议计划的目标是设计和合成新的荧光核苷类似物，并将其作为核酸结构、动力学和识别的探针。推进有效的基于荧光的工具来探索核酸及其与配体和潜在治疗剂的相互作用，将进一步促进新的 诊断方法，并将促进药物发现。该项目的具体目标是：目标1。设计、合成和掺入新型同晶型荧光核苷类似物。主要设计标准包括：（i）与天然核碱基的高度结构相似性，以忠实地模拟它们的大小和形状，以及杂交和识别性质，（ii）Re移位吸收光谱，以最小化与天然碱基的吸收的重叠，以及（iii）足够的发射量子效率和长发射波长（优选在可见光范围内）。将设计有效的合成途径，为自动化和酶促寡核苷酸合成提供核苷和必要的构件。 AIM 2.对修饰的核苷和寡核苷酸进行免疫学和生物免疫学表征。物理特性（例如，吸收和发射最大值、量子产率和亮度、激发态寿命以及对环境极性的敏感性和天然核苷的静态和动态淬灭）将被严格评估和解释。 AIM 3.在生物物理和发现分析中实现有前途的发射类似物。这些试验将有助于：（i）靶向细菌核糖体的新抗生素的发现（ii）RNA解旋酶的研究，普遍存在的马达蛋白，其参与RNA代谢的几乎每个方面，（iii）程序化核糖体移码的监测，该过程可能对天然蛋白质合成极其有害，但是，当程序化（例如，（iv）RNA脱氨基作用的研究，这是一个重要的转录后过程，它使mRNA和所产生的蛋白质多样化;它与适当的脑功能有关，并且当有缺陷时，与疾病有关，以及（v）RNAi的研究，RNAi是由短干扰RNA（siRNA）诱导的调节过程，其也是能够改变细胞表型的有力工具，破译基因通路并确定新的治疗靶点。 核酸在细胞活动中起着核心作用，因此对疾病的出现以及反过来对人类健康产生巨大影响。这就需要开发新的有效的工具来研究它们的识别特性和外源性试剂的改变。所设计和制备的发射性核苷类似物将在新型的基于真实的时间荧光的测定中实施。这些研究将进一步从根本上了解与疾病发展相关的关键生物学过程，并将通过推进知识和促进药物发现对改善人类健康产生长期影响。

DESCRIPTION (provided by applicant): The goal of the proposed program is to design and synthesize new fluorescent nucleoside analogs and implement them as probes for nucleic acids structure, dynamics and recognition. Advancing effective fluorescence-based tools for exploring nucleic acids and their interactions with ligands and potential therapeutic agents will further new diagnostic approaches and will facilitate drug discovery. The specific aims of this project are: AIM 1. To design, synthesize and incorporate new isomorphic fluorescent nucleoside analogs. The main design criteria include: (i) High structural similarity to the native nucleobases to faithfully mimic their size and shape, as well as hybridization and recognition properties, (ii) Re shifted absorption spectrum to minimize overlap with the absorption of the natural bases, and (iii) Adequate emission quantum efficiency and long emission wavelengths (preferably in the visible range). Efficient synthetic pathways will be devised, providing the nucleosides and the necessary building blocks for automated and enzymatic oligonucleotide synthesis. AIM 2. To photophysically and biophysically characterize the modified nucleosides and oligonucleotides. The photophysical characteristics (e.g., absorption and emission maxima, quantum yield and brightness, excited state lifetime, as well as susceptibility to environmental polarity and static and dynamic quenching by native nucleosides) will be rigorously evaluated and interpreted. AIM 3. To implement the promising emissive analogs in biophysical and discovery assays. These assays will facilitate: (i) The discovery of new antibiotics targeting the bacterial ribosome (ii) The study of RNA helicases, ubiquitous motor proteins, which are involved in nearly every aspect of RNA metabolism, (iii) The monitoring of programmed ribosomal frameshifting, a processes which could be extremely detrimental to native protein synthesis, but, when programmed (e.g., in viruses) can maximize protein expression, (iv) The study of RNA deamination, an important posttranscriptional process, which diversifies mRNAs and the resultant proteins; it is linked to proper brain function and, when defective, to disease, and (v) The study of RNAi, a regulatory process induced by short interfering RNA (siRNA), which is also a powerful tool capable of altering cellular phenotypes, deciphering genetic pathways and identifying new therapeutic targets. Nucleic acids play central roles in cellular events and, as such, have immense impact on the emergence of diseases and, in turn, on human health. This necessitates the development of new effective tools for studying their recognition properties and alteration by exogenous agents. The emissive nucleoside analogs designed and prepared will be implemented in novel real time fluorescence-based assays. These investigations will further the fundamental understanding of key biological processes related to disease development and will have long-term impact on improving human health by advancing knowledge and facilitating drug discovery.