The structure, dynamics and function of the pore-forming toxin of Anthrax

描述（由申请方提供）：保护性抗原（PA）是炭疽毒素的受体结合组分，在炭疽酶组分、致死因子（LF）和水肿因子（EF）易位至宿主细胞中起关键作用。PA形成了一个非组成性的b桶孔内体膜的过程中，涉及其分子间相互作用与其受体（ANTXR1或ANTXR2）在酸性pH值。我们的主要目的是这个补助金申请是了解PA和它的目标受体，导致孔形成之间的结构和动态相互作用定义不清。为了实现这些目标，我们打算研究膜插入孔和PA与其受体的相互作用，在原子分辨率使用核磁共振（NMR）和生化技术相结合。使用这些程序，我们将（1）解决胶束内形成的PA孔的高分辨率结构，（2）评估在不同pH值范围内导致孔形成的七聚体PA的动力学，以及（3）检查当PA：受体复合物进入低pH环境时控制PA：受体复合物的结构和动力学变化。我们的调查结果将提供的基础，了解的PA：受体复合物的结构重排，导致孔的形成，并提供洞察易位过程的原子细节的七聚体孔。这些研究的结果将为设计新的治疗方法以阻断炭疽毒素孔的形成和易位到细胞中提供合理的基础。

DESCRIPTION (provided by applicant): Protective Antigen (PA) is the receptor-binding component of the anthrax toxin that plays a pivotal role in the translocation of the anthrax enzymatic components, Lethal Factor (LF) and Edema Factor (EF) into host cells. PA forms a non-constitutive b-barrel pore in endosomal membranes by a process that involves its intermolecular interactions with its receptor (ANTXR1 or ANTXR2) at acidic pH. Our main objective of this grant application is to understand the poorly defined structural and dynamic interactions between PA and its target receptor that lead to pore formation. To accomplish these goals, we intend to study the membrane inserted pore and the interaction of PA with its receptor at atomic resolution using a combination of nuclear magnetic resonance (NMR) and biochemical techniques. Using these procedures, we will (1) solve the high- resolution structure of the PA pore formed within micelles, (2) evaluate the dynamics of the heptameric PA that leads to pore formation at a range of different pH values, and (3) examine the structural and dynamic changes that govern the PA:receptor complex as it enters into a low pH environment. The results of our investigation will provide the basis for understanding the structural rearrangements of the PA:receptor complex that lead to pore formation, and give insights into the translocation process with the atomic details of the heptameric pore. Results of these studies will be the foundation for the rational basis for designing novel therapeutics to block anthrax toxin pore formation and translocation into cells.