Structure and Function of Bacterial RecN Protein

描述(由申请人提供)：这项研究提案的总体目标是揭示RecN的分子功能，RecN是一种对细菌DNA双链断裂(DSB)修复至关重要的蛋白质。细菌RecN蛋白与染色体结构维持蛋白(SMC)家族有显著的同源性。真核SMC蛋白在染色体凝聚、姐妹染色单体凝聚和重组DNA修复等多种DNA代谢过程中具有重要的管家和肿瘤抑制作用。尽管广泛的遗传学证据强调了RecN蛋白对细菌基因组维持的重要性，但还没有对其功能进行实质性的生化研究，因此，还没有确定需要RecN的特定反应。这种情况反映了几个研究小组在处理大肠杆菌(一种模式细菌生物体)RecN蛋白时遇到的困难，因为过度表达的蛋白不能溶解。然而，我们已经确定了一种在大肠杆菌中表达时可溶的RecN同源物，并准备启动初步研究，以建立细菌RecN蛋白在重组DNA修复途径中的生化功能的可测试假说。这项工作将为理解真核SMC蛋白在基因组维持中所起的分子作用提供有价值的模型。 公共卫生相关性：生物化学方法为理解SMC蛋白在基因组维持和重组DNA修复中所起的分子作用提供有价值的模型。

DESCRIPTION (provided by applicant): The overall goal of this research proposal is to reveal the molecular function of RecN, a protein critical to the repair of DNA double-stranded breaks (DSBs) in bacteria. Bacterial RecN proteins share significant homology to the Structural Maintenance of Chromosomes (SMC) family of proteins. Eukaryotic SMC proteins have essential (although not fully understood) house keeping and tumor suppressor roles in a variety of DNA metabolic processes such as chromosomal condensation, sister chromatid cohesion and recombinational DNA repair. Although extensive genetic evidence underscores the importance of RecN proteins to bacterial genome maintenance, there has been no substantive biochemical investigation into their function and, consequently, the specific reactions requiring RecN have not been identified. This situation reflects the difficulties encountered in working with the Escherichia coli (a model bacterial organism) RecN protein by several research groups due to insolubility of the over-expressed protein. However, we have identified a RecN homolog that is soluble when expressed in E. coli and are positioned to initiate pilot studies to establish testable hypotheses for the biochemical function of bacterial RecN proteins in recombinational DNA repair pathways. This work will provide valuable models for understanding the molecular role that eukaryotic SMC proteins play in genome maintenance. PUBLIC HEALTH RELEVANCE: Biochemical approaches to provide valuable models for understanding the molecular role that SMC proteins play in genome maintenance and recombinational DNA repair.