Collaborative Proposal: Elucidating Chemical Mechanisms of DNA Repair Using Transition State Analogs

DNA生命蓝图中的信息可能会被细胞代谢和环境暴露造成的DNA碱基损伤所侵蚀。 修饰的DNA碱基导致DNA序列的变化，称为突变。这些突变会对细胞过程产生负面影响，但它们可以通过DNA修复酶的作用进行纠正。 有了这个奖项，化学部的生命过程化学项目正在资助加州大学戴维斯分校的希拉大卫博士和犹他州大学的马丁·霍瓦特博士，以揭示受损DNA碱基如何被检测和修复的分子细节。 该研究利用合成DNA化学和X射线晶体学来捕获和可视化DNA修复过程中的步骤，这些步骤否则太短暂而无法研究，并生成DNA修复过程的详细分子图像。 研究生和本科生学习如何将联合收割机不同的化学和生物学方法结合起来，以揭示和理解基本生命过程的关键特征。该项目还被整合到一个独特的“基于课程的研究经验”（CURE）实验室课程，在加州戴维斯大学和犹他州大学教授。 本科生从课程中脱颖而出，提高了批判性思维能力，并更好地了解了对生物体至关重要的信息如何在其DNA中编码并由DNA修复酶维持。该研究项目描述了碱基切除修复（BER）糖基化酶的化学机制，以阐明这些酶如何有效地找到罕见的修饰DNA碱基。模拟过渡态的修饰核苷酸通过合成化学制备。结合到DNA含有这些过渡态模拟物的几个BER糖基化酶的结构研究提供了深入了解碱基切除的催化作用。事实上，三种BER糖基化酶，即MutY，AlkD和MBD 4，发现了令人惊讶的特征，对这些和相关的糖基化酶提出了新的问题，并促使大卫和霍瓦特研究小组进行新的创新结构和功能研究。 从事该项目的学生接受跨学科的培训，涵盖合成核酸化学，核酸酶学和DNA蛋白质晶体学。培养妇女和少数民族学生茁壮成长的环境是该奖项支持的工作的核心目标。这个项目有一个积极的更广泛的教育影响，因为它是绑在两个本科实验室课程，介绍新生和先进的本科生在化学生物学中使用的现代研究技术和方法，重点是DNA损伤和修复。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

The information held within the DNA blueprint for life can be eroded by damage to DNA bases due to cellular metabolism and environmental exposures. Modified DNA bases lead to changes in the DNA sequence called mutations. These mutations can negatively impact cellular processes but they can be corrected by the action of DNA repair enzymes. With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Sheila David at the University of California Davis and Dr. Martin Horvath at the University of Utah to uncover molecular details of how damaged DNA bases are detected and repaired. The research makes uses of synthetic DNA chemistry and X-ray crystallography to trap and visualize steps in the DNA repair process that are otherwise too fleeting to study and to generate a detailed molecular picture of the DNA repair process. Graduate and undergraduate students learn how to combine different chemistry and biology approaches to reveal and understand key features of fundamental life processes. This project is also integrated into a unique "Course-Based Research Experience" (CURE) laboratory course taught at both the University of California Davis and the University of Utah. Undergraduates emerge from the course with improved critical thinking skills and a better conceptual knowledge of how information crucial for living organisms is encoded in their DNA and maintained by DNA repair enzymes. This research project delineates chemical mechanisms of base excision repair (BER) glycosylases to illuminate how these enzymes efficiently find rare modified DNA bases. Modified nucleotides that mimic transition states are prepared through synthetic chemistry. Structural studies of several BER glycosylases bound to DNA containing these transition state mimics provide insight into the catalysis of base excision. Indeed, surprising features uncovered with three BER glycosylases, namely MutY, AlkD and MBD4, raise new questions on these and related glycosylases and prompt new innovative structural and functional studies that will be pursued by the David and Horvath research groups. Students working on this project receive interdisciplinary training spanning synthetic nucleic acid chemistry, nucleic acid enzymology, and DNA-protein crystallography. Fostering environments in which women and minority students thrive is a core goal of the work supported by this award. This project has a positive broader educational impact because it is tied to two undergraduate laboratory courses that introduce incoming and advanced undergraduate students to modern research techniques and approaches used in chemical biology with a focus on DNA damage and repair.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.