Physical Mechanisms of Bacterial Genome Maintenance

描述（由申请方提供）：细菌单链（ss）DNA结合蛋白（SSB）在基因组生物学中发挥重要的保护和组织作用。为了保护ssDNA免受潜在的损伤，多个SSB组装成“核小体样”支架，其结构尚不清楚。ssDNA/SSB复合物远非惰性，而是活性DNA加工中心，其中至少有十几种不同的酶通过利用与SSB的直接蛋白质-蛋白质相互作用而获得基因组底物。在迄今为止检查的所有情况下，SSB的柔性C-末端（SSB-Ct）形成异源蛋白质的对接位点。蛋白质如何与SSB-Ct序列结合，以及这些基本相互作用如何影响基因组维持酶的活性，仍然没有很好的定义。鉴于SSB与异源蛋白相互作用的重要性，阻断这些SSB蛋白复合物形成的抑制剂作为新型抗菌剂具有很大的潜力。该提案的最终目标是阐明ssDNA/SSB底物的结构，揭示酶如何利用与SSB的直接结合来处理这些结构，并表征阻断异源蛋白与SSB结合的抑制剂的抗菌特性。该提案汇集了生物化学，结构和遗传学方法来解决这些问题。公共卫生相关性：基因组维护过程确保细胞中遗传信息的准确性，并提供了这些信息可以忠实复制并分配给子细胞的机制。这些是所有细胞的基本过程，需要许多不同蛋白质的精确协调。该提案旨在了解这些蛋白质组分中的几种如何在细胞中协调，并研究选择性阻断细菌中这种协调的抑制剂的抗菌机制。

DESCRIPTION (provided by applicant): Bacterial single-strand (ss) DNA-binding proteins (SSBs) play essential protective and organizational roles in genome biology. To shield ssDNA from potential damage, multiple SSBs assemble into "nucleosome-like" scaffolds, the structures of which are not well understood. Far from being inert, ssDNA/SSB complexes are active DNA processing centers where at least a dozen different enzymes gain access to genomic substrates by exploiting direct protein-protein interactions with SSB. In all cases examined to date, SSB's flexible C-terminus (SSB-Ct) forms a docking site for heterologous proteins. How proteins bind to the SSB-Ct sequence and how these essential interactions affect the activities of genome maintenance enzymes remains poorly defined. Given the importance of SSB's interactions with heterologous proteins, inhibitors that block formation of these SSB protein complexes have great potential as novel anti-bacterial agents. The ultimate goals of this proposal are to elucidate the structures of ssDNA/SSB substrates, to reveal how enzymes take advantage of direct binding to SSB to process these structures, and to characterize the anti-bacterial properties of inhibitors that block heterologous protein association with SSB. The proposal brings together biochemical, structural, and genetic approaches to address these questions. PUBLIC HEALTH RELEVANCE: Genome maintenance processes ensure the accuracy of genetic information in cells and provide mechanisms whereby this information can be faithfully duplicated and distributed to daughter cells. These are essential process for all cells and require precise coordinate of many different proteins. This proposal aims to understand how several of these protein components are coordinated in cells and to investigate the anti-bacterial mechanisms of inhibitors that selectively block this coordination in bacteria.