STRUCTURAL STUDIES OF DNA GLYCOSYLASES WITH DAMAGED DNA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 DNA四个碱基的自发损伤是导致癌症的突变的主要原因。这些遗传损伤中的大多数都可以通过一种称为碱基切除DNA修复(BER)的途径来纠正。BER的关键成分是DNA糖基酶，这种酶扫描基因组以寻找特定类型的碱基损伤，然后通过催化从DNA骨架上切除受损的碱基来启动修复过程。我们研究的长期目标是了解他们利用的准确反应途径。对DNA损伤识别和移除的全面、基本的了解代表了肿瘤发生之谜的一个主要方面的解决方案。 在拟议的研究中，我们将重点研究DNA糖基酶修复DNA中8-氧鸟嘌呤碱基的人Ogg1蛋白修复碱基切除的详细反应途径。在DNA糖基酶，尤其是hOgg1的底物识别和催化的结构生物学方面，有大量的文献。在拟议的工作中，我们试图从结构上表征hOgg1反应途径中的早期中间产物，在那里它正在采样受损的DNA。通过设计合适的突变体和使用共价捕获策略，我们能够捕获催化途径中不同状态的酶。通过获得这些中间体的高分辨结构，我们的目标是了解整个催化途径的不同成分。 参考文献：Nat Struct Biol。2003年3月；10(3)：204-11生物化学。2003年2月8日；42(6)：1564-72。大自然。2000年2月24日；403(6772)：859-66

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Spontaneous damage to the four bases of DNA is a major cause of the mutations that give rise to cancer. Most of these genetic lesions are corrected by a pathway known as base-excision DNA repair (BER). The key components of BER are DNA glycosylases, enzymes that scan the genome in search of particular kinds of base damage, then initiate the repair process by catalyzing excision of the damaged base from the DNA backbone. The long-term goals of our studies are to understand the precise reaction pathways that they utilize. A comprehensive, fundamental understanding of DNA damage recognition and removal represents the solution to a major aspect of the tumorigenesis puzzle. In the proposed studies, we will focus on the detailed reaction pathway of base-excision repair by the DNA glycosylase, human Ogg1 protein which repairs 8-oxoguanine bases in DNA. There is an ample body of work in the literature on the structural biology of substrate recognition and catalysis by DNA glycosylases, especially hOgg1. In the proposed work here, we are trying to structurally characterize early intermediates in the reaction pathway of hOgg1 where it is sampling damaged DNA. By designing suitable mutants and using a covalent trapping strategy, we are able to trap the enzyme in different states of the catalytic pathway. By obtaining high resolution structures of these intermediates, we aim to understand the different components of the entire catalytic pathway. References: Nat Struct Biol. 2003 Mar;10(3):204-11 Biochemistry. 2003 Feb 8;42(6):1564-72. Nature. 2000 Feb 24;403(6772):859-66