Functions of the PcrA Helicase in Bacillus anthracis

炭疽杆菌中 PcrA 解旋酶的功能

• 批准号: 7039308
• 负责人: SALEEM A. KHAN
• 金额: $ 22.28万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7039308
• 关键词: Bacillus anthracis; DNA; genes; helicase; metabolism; plasmids; role; virulence

DESCRIPTION (provided by applicant): Bacillus anthracis is an important human pathogen and a potential biological weapon. Drug therapy is available to treat B. anthracis infections since most strains are usually antibiotic sensitive. However, the possibility that bioterrorists may introduce drug resistance plasmids into B. anthracis to generate "super bioterror agents", or such plasmids may transfer naturally into B. anthracis cannot be discounted. Therefore, it is important to identify new drug targets for this organism. PcrA is an essential helicase in Gram-positive bacteria, but its precise function(s) are not known. Gene knock-out experiments will be carried out to confirm that inactivation of the pcrA gene is lethal for B. anthracis. Biochemical studies will be carried out using purified PcrA helicase from B. anthracis to study its role in cellular DNA metabolism. Using substrates that represent DNA molecules that are intermediates in processes such as DNA replication, recombination and repair, we plan to study the DNA binding and helicase activities of PcrA. These studies will reveal whether PcrA is involved in the processing of the Okazaki fragments during DNA replication, and whether it is an editing helicase for the resolution of toxic recombination intermediates. We will carry out experiments to test whether PcrA can block the formation of recombination intermediates such as D-loop and whether it can displace the RecA protein bound to single-stranded DNA. We will also carry out genetic experiments to test whether PcrA is required for the replication of the pXO1 and pXO2 virulence plasmids of B. anthracis. Future development of drugs that specifically inhibit the functions of the PcrA helicase could add to the treatment regimen against B. anthracis and related organisms.

描述（申请人提供）：炭疽杆菌是一种重要的人类病原体，也是一种潜在的生物武器。药物疗法可用于治疗炭疽杆菌感染，因为大多数菌株通常对抗生素敏感。然而，生物恐怖分子可能将耐药质粒引入炭疽杆菌中以产生“超级生物恐怖剂”，或者此类质粒可能自然转移到炭疽杆菌中，这种可能性不能被低估。因此，确定该生物体的新药物靶点非常重要。 PcrA 是革兰氏阳性菌中的一种必需解旋酶，但其确切功能尚不清楚。将进行基因敲除实验以确认pcrA基因失活对于炭疽芽孢杆菌是致命的。将使用来自炭疽芽孢杆菌的纯化 PcrA 解旋酶进行生化研究，以研究其在细胞 DNA 代谢中的作用。我们计划使用代表 DNA 分子（DNA 复制、重组和修复等过程中的中间体）的底物来研究 PcrA 的 DNA 结合和解旋酶活性。这些研究将揭示PcrA是否参与DNA复制过程中冈崎片段的加工，以及它是否是用于解析有毒重组中间体的编辑解旋酶。我们将进行实验来测试PcrA是否可以阻断D环等重组中间体的形成，以及是否可以取代与单链DNA结合的RecA蛋白。我们还将进行遗传实验来测试炭疽芽孢杆菌pXO1和pXO2毒力质粒的复制是否需要PcrA。未来开发专门抑制 PcrA 解旋酶功能的药物可能会增加针对炭疽杆菌和相关生物体的治疗方案。