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

有了这个奖项，化学部的生命过程化学计划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·霍瓦特博士研究如何检测和修复DNA损伤。DNA是生命的蓝图，细胞代谢或环境危害对这种分子造成的损害可能导致突变，细胞死亡或在进化过程中蓝图的变化。DNA的保存依赖于DNA修复酶的作用。 尽管多年的工作已经揭示了DNA修复酶及其作用的损伤类型，但这些神奇的酶在化学水平上如何工作仍然是个谜。该项目使用合成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，否则这些步骤太短暂而无法研究。 这种策略提供了DNA修复过程的详细分子图像。 该项目采用多方面的方法来研究几种专门修复受损DNA碱基的酶。参与该项目的研究生和本科生正在接受合成、生物化学和X射线晶体学方面的培训。该项目的发现和结果正在被纳入加州大学戴维斯分校和犹他州大学的DNA损伤和修复本科实验室课程。本研究课题旨在通过对碱基切除修复（BER）糖基化酶的化学机制的研究，阐明BER糖基化酶如何有效地发现罕见的修饰DNA碱基，从而提高学生的批判性思维能力和概念性知识。模拟过渡态的修饰核苷酸正在通过合成化学制备。结合到DNA含有这些过渡态类似物的几个BER糖基化酶的结构研究揭示了这些酶催化碱基切除所使用的策略。初步工作揭示了BER糖基化酶MutY和AlkD的几个令人惊讶的特征，并促使对这些和相关BER糖基化酶进行新的结构和机制研究。该项目揭示了DNA修复化学中的共同主题和独特特征。

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 investigate how DNA damage is detected and repaired. DNA is the blueprint for life, and damage to this molecule caused by cellular metabolism or by environmental hazards can lead to mutations, cell death or changes in the blueprint over the course of evolution. The preservation of DNA relies on the action of DNA repair enzymes. Despite years of work that has uncovered DNA repair enzymes and the types of damage upon which they act, mysteries remain as to how these amazing enzymes work at the chemical level. This project uses synthetic DNA chemistry and X-ray crystallography to trap and visualize steps, in the DNA repair process, that are otherwise too fleeting to study. This strategy provides a detailed molecular picture of the DNA repair process. The project applies a multi-faceted approach to investigate several enzymes that specialize in repairing damaged DNA bases. Graduate and undergraduate students involved in this project are receiving training in synthesis, biochemistry and X-ray crystallography. The discoveries and results produced by this project are being incorporated into a DNA damage and repair undergraduate laboratory class at UC Davis and at the University of Utah. Undergraduate students in these courses will emerge with skills in critical thinking and conceptual knowledge related to how the information of life is encoded in DNA and maintained by DNA repair enzymes.This research project delineates chemical mechanisms of base excision repair (BER) glycosylases and illuminates how these enzymes efficiently find rare modified DNA bases. Modified nucleotides that mimic transition states are being prepared through synthetic chemistry. Structural studies of several BER glycosylases bound to DNA containing these transition state analogs are revealing the strategies used by these enzymes to catalyze base excision. Preliminary work has revealed several surprising features of the BER glycosylases MutY and AlkD, and prompted novel structural and mechanistic studies on these and related BER glycosylases. This project is revealing common themes and unique features in the chemistry underlying DNA repair.