Mechanisms of Anthrax Virulence Factor AtxA.

描述（由申请方提供）：炭疽芽孢杆菌质粒携带基因atxA编码炭疽毒素表达的主要调节因子。虽然它在致病性中的作用已被遗传学证实，但其作用的机制细节仍不清楚。我们发现它的产物AtxA在体内与炭疽RNA聚合酶结合，并在体外证明了它的转录活性。利用我们在阐明基因表达的各种细菌调节剂的结构和生化机制方面的广泛和在许多方面独特的经验，我们提出了AtxA结构和功能研究的全面计划。作为拟议的研究的结果，AtxA在炭疽毒素的表达中的作用的详细了解将出现，完成其作用的分子机制的深入调查，彻底分析该因子的差异磷酸化和其转录活性之间的相互作用，以及该因子在“ON”和“OFF”状态下的高分辨率结构。总之，这些见解将允许更好地了解炭疽的毒力和致病性，同时作为一个起点的AtxA为基础的抑制剂的炭疽毒素生产的这种重要的人畜共患病原体和A类代理的结构为基础的设计。 公共卫生相关性：炭疽杆菌是人畜共患病炭疽感染的常规原因，并已被用作美国土地上的生物恐怖武器。我们提出了一个全面的计划，炭疽毒力和毒素生产的主要调节因子，转录因子AtxA的生化和结构研究。作为这项研究的结果，AtxA的作用机制的详细了解将出现，而必要的结构和生物化学信息将被收集，其评估作为一个目标，以知识为基础的药物设计。

DESCRIPTION (provided by applicant): Bacillus anthracis plasmid-borne gene atxA encodes a major regulator of anthrax toxin expression. Although its role in virulence has been confirmed genetically, the mechanistic details of its action remain obscure. We have discovered that its product, AtxA, binds to anthrax RNA polymerase in vivo, and demonstrated its transcriptional activity in vitro. Using our extensive and in many ways unique experience in elucidating structural and biochemical mechanisms of various bacterial regulators of gene expression we propose a comprehensive plan of AtxA structural and functional research. As a result of the proposed research a detailed understanding of AtxA role in the expression of the anthrax toxin will emerge, complete with in-depth investigation of the molecular mechanism of its action, thorough analysis of the interplay between the differential phosphorylation of this factor and its transcriptional activity, and a high resolution structure of this factor in the "ON" and "OFF" states. Altogether these insights would allow for a better understanding of anthrax virulence and pathogenicity, while serving as a starting point of the structure-based design of AtxA-based inhibitors of anthrax toxin production by this important zoonotic pathogen and a Category A agent. PUBLIC HEALTH RELEVANCE: Bacillis anthracis is a routine cause of zoonotic anthrax infections and has been used as a bioterrorist weapon on the US soil. We propose a comprehensive plan of biochemical and structural research of the main regulator of anthrax virulence and toxin production, transcription factor AtxA. As the result of this research, a detailed understanding of AtxA mechanism of action will emerge while necessary structural and biochemical information will be gathered for its evaluation as a target for knowledge-based drug design.