Functions of the PcrA Helicase in Bacillus anthracis

炭疽杆菌中 PcrA 解旋酶的功能

• 批准号: 7229785
• 负责人: SALEEM A. KHAN
• 金额: $ 18.02万
• 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/7229785
• 关键词: Anthrax disease; Antibiotics; Bacillus anthracis; Biochemical; Biological; Categories; DNA; DNA Binding; DNA biosynthesis; Development; Drug Delivery Systems; Drug resistance; Essential Genes; Future; Genes; Genetic; Genetic Recombination; Gram-Positive Bacteria; Growth; Human; Infection; Knock-out; Maintenance; Metabolism; Molecular Genetics; National Institute of Allergy and Infectious Disease; Okazaki fragments; Organism; Pharmacotherapy; Plasmids; Process; Protein Binding; Rec A Recombinases; Resolution; Role; Single-Stranded DNA; Testing; Treatment Protocols; Virulence; discount; drug development; helicase; pathogen; recombinational repair; research study

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。由于大多数菌株通常对抗生素敏感，因此可以使用药物疗法来治疗炭疽杆菌感染。然而，生物恐怖分子可能会将抗药性质粒引入炭疽杆菌中，以产生“超级生物恐怖制剂”，或者此类质粒可能会自然转移到炭疽杆菌中，这一可能性不能被忽视。因此，为这种生物确定新的药物靶点是很重要的。PcrA是革兰氏阳性菌中一种必不可少的解旋酶，但其确切功能尚不清楚(S)。将进行基因敲除实验，以确认PcrA基因的失活对炭疽杆菌是致命的。将使用从炭疽杆菌中纯化的PcrA解旋酶进行生化研究，以研究其在细胞DNA代谢中的作用。利用代表DNA分子的底物，如DNA复制、重组和修复过程中的中间体，我们计划研究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，以及它是否是一种用于分解有毒重组中间体的编辑解旋酶。我们将进行实验，以测试PcrA是否可以阻止D-loop等重组中间产物的形成，以及它是否可以取代与单链DNA结合的RecA蛋白。我们还将进行基因实验，以测试PcrA是否是复制炭疽杆菌pXO1和pXO2毒力质粒所必需的。未来专门抑制PcrA解旋酶功能的药物的开发可能会增加对抗炭疽杆菌和相关生物的治疗方案。