Next-Generation Fluorescent Nucleosides and Structure-Photophysics Relationships

在这个由化学学部化学结构、动力学和机制B项目资助的项目中，圣地亚哥州立大学化学和生物化学系的Byron Purse教授正在开发荧光核苷类似物作为分子探针，具有核酸生物物理研究的新功能。核酸除了储存遗传密码外，还可以进行化学修饰，采用折叠结构，并与蛋白质和酶相互作用，调节基因的表达和代谢。荧光核苷类似物是研究这些过程的有力探针，但现有的类似物能力有限。对控制其荧光的因素了解不足阻碍了更好的探针的合理设计。该项目旨在克服这些限制，并扩大荧光核苷类似物探针的工具包具有重要的，新颖的能力。新的类似物的设计是通过详细的机制研究如何在DNA/RNA的局部环境影响探针的荧光。这项跨学科的研究为学生提供了多层次的良好训练机会。除了研究生和本科生的参与外，SDSU物理化学教学实验室的基于课程的本科生研究经验（CURE）以及与社区大学和高中学生一起进行的涉及计算工作的外展计划将扩大研究的参与。在设计模拟生物分子结构的荧光探针时，最大的挑战可能是预测光物理性质的能力有限，目前需要尝试和错误的方法。在这个项目中，光物理测量、计算、核磁共振和x射线结构测定相结合，对核苷类似物结构和光物理之间的关系进行了详细的、预测性的理解，特别是在DNA和RNA的基础堆栈中。通过利用这些趋势和合成新的荧光核苷类似物设计，正在开发具有(a)与传统荧光团匹配的亮度的新型探针，(b)在可见光谱的红端吸收和发射，(c)对特定生物分子识别事件的强荧光开启响应，以及(d)报告核碱基化学修饰的能力，例如甲基化或DNA损伤。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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 (SDSU) is developing fluorescent nucleoside analogues as molecular probes with new capabilities for biophysical studies of nucleic acids. In addition to storing the genetic code, nucleic acids can undergo chemical modification, adopt folded structures, and interact with proteins and enzymes for the regulation of gene expression and metabolism. Fluorescent nucleoside analogues are powerful probes for studying these processes, but existing analogues have limited capabilities. Insufficient knowledge of the factors controlling their fluorescence hinders the rational design of better probes. This project seeks to overcome these limitations and expand the toolkit of fluorescent nucleoside analogue probes with significant, novel capabilities. The design of the new analogues is aided by detailed mechanistic studies of how the local environment in DNA/RNA influences the fluorescence of the probes. This cross-disciplinary research provides excellent training opportunities for students at multiple levels. In addition to graduate student and undergraduate involvement, a Course-based Undergraduate Research Experience (CURE) in the SDSU Physical Chemistry teaching lab and an outreach program involving computational work with community college and high school students will broaden participation in the research.Probably the greatest challenge in designing fluorescent probes that mimic the structure of biomolecules is that limited ability to predict photophysical properties currently necessitates a trial-and-error approach. In this project, photophysical measurements, computation, NMR, and x-ray structure determination are combined to develop a detailed, predictive understanding of the relationships between nucleoside analogue structure and photophysics, especially in the base stack of DNA and RNA. By harnessing these trends and synthesizing new fluorescent nucleoside analogue designs, novel probes with (a) brightness matching conventional fluorophores, (b) absorption and emission at the red end of the visible spectrum, (c) strong fluorescence turn-on responses to specific biomolecular recognition events, and (d) the ability to report on chemical modifications to nucleobases, e.g. from methylation or DNA damage are being developed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.