Bright and responsive fluorescent nucleosides from structure-photophysics relationships

在这个由化学系化学结构、动力学和机制B计划资助的项目中，圣地亚哥州立大学化学和生物化学系的拜伦·普尔斯教授正在开发下一代荧光核苷，作为研究核酸的工具。除了存储遗传密码外，核酸还在基因表达和新陈代谢中发挥着许多重要的调节作用。荧光核苷是一种经过化学修饰的核酸构件，广泛用于旨在了解基因表达调控的生物物理研究中。该项目旨在加强对这些核苷探针结构和荧光性质之间关系的了解，并利用这些知识为荧光核苷类似物的工具箱增加新的功能。研究计划的组成部分是在圣地亚哥州立大学物理化学教学实验室研究这些新的核苷类似物的荧光性质，以及在计算工作中针对高中和社区大学生的推广计划。合理设计具有特定目标性质的荧光核苷类似物是一个巨大的挑战，因为根据结构预测光物理性质是困难的，特别是在像核酸双链体这样的复杂环境中。在这个项目中，光物理研究和密度泛函理论相结合的方法被用来建立结构-光物理关系，以开发具有所需荧光性质的下一代荧光核苷。所需的荧光特性包括：(A)对碱基堆积的大荧光开启反应(即100倍)，(B)与传统荧光团匹配的亮度，足以使单分子生物物理和荧光显微镜跟踪标记的核酸，以及(C)在可见光谱的红端吸收和发射的类似物。

In this project funded by the Chemical Structure, Dynamics and Mechanisms B Program of the Chemistry Division, Professor Byron Purse of the Department of Chemistry and Biochemistry at San Diego State University is developing next-generation fluorescent nucleosides as tools for studying nucleic acids. In addition to storing the genetic code, nucleic acids have many important regulatory roles in gene expression and metabolism. Fluorescent nucleosides are chemically modified building blocks of nucleic acids that are widely used in biophysical studies aimed at understanding the regulation of gene expression. This project aims to enhance the understanding of the relationship between structure and fluorescence properties of these nucleoside probes, and to use this knowledge to add new capabilities to the toolkit of fluorescent nucleoside analogues. Integral to the research plan is the studying of the fluorescence properties of these new nucleoside analogues in the Physical Chemistry teaching laboratory of San Diego State University and an outreach program targeting high school and community college students in the computational work.The rational design of fluorescent nucleoside analogues with specifically targeted properties is a great challenge because predicting photo-physical properties based on structure, especially in a complex environment like a nucleic acid duplex, is difficult to achieve. In this project, photophysical studies coupled with density functional theory methods are being used to establish structure-photophysics relationships, in order to develop next-generation fluorescent nucleosides with desired fluorescence properties. The desired fluorescence properties include: (a) large fluorescence turn-on responses to base stacking (i.e. 100-fold), (b) brightness matching conventional fluorophores, sufficient to enable single-molecule biophysics and tracking of labeled nucleic acids by fluorescence microscopy, and (c) analogues that absorb and emit at the red end of the visible spectrum.