Structure and Function of the B. Anthracis Exosporium

炭疽杆菌外孢子的结构和功能

• 批准号: 6832743
• 负责人: CHARLES LEE TURNBOUGH
• 金额: $ 36.55万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6832743
• 关键词: Bacillus anthracis; SDS polyacrylamide gel electrophoresis; X ray crystallography; anthrax; bacteria infection mechanism; bacterial capsules; bacterial proteins; bioterrorism /chemical warfare; crosslink; gene mutation; genetic strain; glycoproteins; host organism interaction; laboratory mouse; microorganism immunology; monoclonal antibody; protein structure function; spores; superoxide dismutase; two dimensional gel electrophoresis; virulence

Bacillus anthracis, the cause of anthrax, has been developed into a weapon of mass destruction by foreign governments and terrorist groups. The recent release of B. anthracis in the United States, with severe consequences, exposed the need for a more effective response to this threat. B. anthracis is used as a weapon largely because it forms highly resistant spores that can be incorporated into explosive weapons and terrorist devices. Spores enter the body through skin abrasions and by ingestion or inhalation and then germinate and grow as vegetative cells. When growth occurs in internal tissues, the host usually dies within several days. Natural strains of B. anthracis are sensitive to common antibiotics; however, large-scale use of these antibiotics to protect against anthrax is logistically difficult and medically dangerous. In addition, antibioticresistant strains may be used in the future. Furthermore, the current vaccine for anthrax has proven problematic. Thus, new strategies are needed to respond to the anthrax threat, and these are likely to require detailed knowledge of the interactions between the mammalian immune system and the outermost surface of the B. anthracis spore - the exosporium. The exosporium serves as the primary interactive site with host defenses, as the source of surface antigens, and as a semi-permeable barrier that excludes antibodies and destructive enzymes. The exosporium consists of a paracrystalline basal layer and an external hair-like nap. Approximately 50% of the mass of the exosporium appears to be proteins, roughly 20 unique species including glycoproteins. Preliminary studies indicate that exosporium proteins play a role in spore virulence. The goal of this project is to determine the content, structure, and function of the external surface of the exosporium. Of primary importance will be the role in virulence of surface-exposed proteins and glycoproteins. Specifically, we will (1) identify these proteins, make mutations that alter them, and examine the effects of the mutations on host-cell interactions and virulence using a mouse model. (2) We will map epitopes on key exosporium proteins, such as the collagen-like protein (BclA) of the hair-like nap, and examine the effects of antibody binding to these epitopes. Of special interest are antibodies that bind exosporium proteins and inhibit spore germination. (3) We will determine the structure of Bc1A and its domains. (4) We will examine the structure and assembly of the basal layer of the exosporium, including the attachment of the hair-like nap. The entire program project is designed to provide sufficient understanding of spore-host interactions to enable the development of new treatments for anthrax.

炭疽杆菌是炭疽病的病原体，已被外国政府和恐怖组织开发成大规模杀伤性武器。最近发布的B。美国的炭疽病造成了严重后果，表明需要对这一威胁作出更有效的反应。B。炭疽菌被用作武器，主要是因为它能形成具有高度抗性的孢子，可用于制造爆炸性武器和恐怖主义装置。孢子通过皮肤擦伤和摄入或吸入进入人体，然后作为营养细胞萌发和生长。当生长发生在内部组织时，宿主通常在几天内死亡。 B的天然菌株。炭疽对普通抗生素敏感;然而，大规模使用这些抗生素来预防炭疽在后勤上是困难的，并且在医学上是危险的。此外，将来可能会使用耐药菌株。此外，目前的炭疽疫苗已被证明存在问题。因此，需要新的策略来应对炭疽威胁，并且这些策略可能需要详细了解哺乳动物免疫系统与B最外层表面之间的相互作用。炭疽孢子-孢子外壁。外孢壁作为与宿主防御的主要相互作用位点，作为表面抗原的来源，以及作为排除抗体和抗原的半渗透屏障。 破坏性酶外孢壁由一个次晶基底层和一个外部毛状绒毛组成。 外孢壁大约50%的质量似乎是蛋白质，大约20种独特的物质，包括糖蛋白。初步研究表明，孢子外壁蛋白在孢子毒力中起作用。 本项目的目标是确定外孢壁外表面的内容、结构和功能。最重要的是表面暴露的蛋白质和糖蛋白在毒力中的作用。具体来说，我们将（1）鉴定这些蛋白质，使突变改变它们，并使用小鼠模型检查突变对宿主细胞相互作用和毒力的影响。(2)我们将绘制关键外孢蛋白（如头发样绒毛的胶原样蛋白（BclA））上的表位，并检查抗体结合这些表位的影响。特别感兴趣的是结合孢子外壁蛋白并抑制孢子萌发的抗体。(3)我们将确定Bc 1A及其结构域的结构。(4)我们将研究外孢壁基底层的结构和组装，包括 毛状绒毛的附着。整个项目旨在提供孢子-宿主相互作用的充分理解，以开发炭疽的新治疗方法。