STRUCTURAL STUDIES OF NUCLEOTIDE EXCISION REPAIR ENZYMES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 内源性和外源性因子对DNA的损伤是基因突变的主要原因，如果损伤未得到纠正，基因突变会导致不同形式的癌症。核苷酸切除修复（NER）是真核生物和原核生物中主要的DNA修复途径之一。 NER系统识别并修复广谱DNA损伤，例如由UV光引起的顺式-顺式胸腺嘧啶二聚体、大体积苯并[a]芘二醇环氧化物（BPDE）鸟嘌呤加合物和顺式-Pt加合物。 细菌中的NER系统由三种主要蛋白质UvrA、UvrB和UvrC组成，所有这些蛋白质都是成功修复损伤所必需的。UvrA对DNA中的受损位点具有很强的亲和力，在识别过程中起着关键作用。它也有一个与UvrB相互作用的结构域。 UvrA识别损伤位点，促进UvrB和DNA之间的相互作用，然后离开损伤位点。UvrB与DNA形成稳定的复合物，随后募集催化性UvrC，其切割病变3'端的第4个磷酸二酯键，然后切割病变5'端的第8个磷酸二酯键。有趣的是，在没有UvrA的情况下，UvrB或UvrC对受损的DNA没有任何亲和力。 虽然这种修复途径已经知道了几十年，但迄今为止只有UvrB和UvrC的结构域结构可用。 本研究的目的是获得核苷酸切除修复酶的晶体结构。

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. Damage to DNA by endogenous and exogenous agents are the major cause of genetic mutations that give rise to different forms of cancer if the damage remains uncorrected. Nucleotide Excision Repair (NER) is one of the major DNA repair pathways functioning in both eukaryotes and prokaryotes. The NER system recognizes and repairs a broad spectrum of DNA lesions, such as cis-syn thymine dimers caused by UV light, bulky benzo[a]pyrene diol epoxide(BPDE) guanine adducts, and cis-Pt adducts. The NER system in bacteria consists of three major proteins, UvrA, UvrB, and UvrC, all of which are essential for successful damage correction. UvrA, which has strong affinity to damaged sites in DNA, has a key role in the recognition process. It also has a domain that interacts with UvrB. UvrA recognizes the site of damage, facilitates the interaction between UvrB and DNA, and then leaves the damaged site. UvrB forms a stable complex with DNA, followed by the recruitment of catalytic UvrC, which cleaves the 4th phosphodiester bond at 3' end of the lesion, and then the 8th phosphodiester bond at 5' end of the lesion. Interestingly, without UvrA, UvrB or UvrC do not have any affinity to damaged DNA. Although this repair pathway has been known for decades, only UvrB and domain structures of UvrC are available to date. In this project, our goal is to obtain crystal structures of nucleotide excision repair enzymes.