X-RAY ANALYSIS OF REPLICATION AND REPAIR PROTEINS

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。 这项工作的目标是1)复制启动和2)核苷酸切除修复(NER)的基于结构的理解。复制始于基因组上的多个位置，称为DNA复制起点。专门的蛋白质复合体结合在这些位点上，并为复制准备双链。这些集合的活动受到严格控制，以确保每个细胞周期只复制一个基因组。这些大型复合体的结构、调节和作用机制尚不完全清楚。我们的工作具有实际意义，因为起源复合体的调控变化有助于人类癌症的发生。细菌复合体的努力将为开发新的抗生素提供亟需的靶标。 NER的第一步由三种蛋白执行：UvrA、UvrB和UvrC。UvrA UvrB套装监测DNA并识别损伤。当遇到损伤时，UvrA离开复合体，使UvrB稳定地结合在病变部位或附近。损伤搜索、DNA复合体的形成和UvrA的解离都受ATP的调控。UvrB然后招募内切酶UvrC，它催化病变两侧的切开。额外的处理反应会导致原始DNA序列的恢复。

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. The goal of this work is a structure-based understanding of 1) replication initiation and 2) nucleotide excision repair (NER). Replication initiates at multiple sites on the genome called origins of DNA replication. Specialized protein complexes bind at these sites and prepare the duplex for replication. The activity of these ensembles is tightly controlled to ensure that only one copy of the genome is made per cell cycle. The architecture, regulation and mechanisms of action of these large complexes are incompletely understood. Our work is of practical significance because regulatory changes in origin complexes contribute to human cancers. Efforts with bacterial complexes will provide much needed targets for development of novel antibiotics. The first steps in NER are performed by three proteins: UvrA, UvrB and UvrC. The UvrA+UvrB ensemble monitors DNA and recognizes damage. On encountering damage, UvrA exits the complex, leaving UvrB stably bound at or near the lesion site. Damage searching, formation of the DNA complex and dissociation of UvrA are regulated by ATP. UvrB then recruits the endonuclease UvrC, which catalyzes incisions on either side of the lesion. Additional processing reactions lead to restoration of the original DNA sequence.