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

描述（由申请人提供）：保护性抗原（PA）是炭疽毒素的受体结合成分，在炭疽酶成分、致死因子（LF）和水肿因子（EF）转运到宿主细胞中起关键作用。在酸性ph下，PA与其受体（ANTXR1或ANTXR2）的分子间相互作用在内体膜上形成了一个非组成的b桶孔。我们的主要目的是了解PA与其靶受体之间的结构和动态相互作用，这些相互作用导致了孔的形成。为了实现这些目标，我们打算利用核磁共振（NMR）和生化技术的结合，在原子分辨率上研究PA的膜插入孔及其与受体的相互作用。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)评估七聚体PA在不同pH值范围内导致孔形成的动力学，以及(3)检查控制PA：受体复合物进入低pH环境时的结构和动态变化。我们的研究结果将为理解导致孔形成的PA：受体复合物的结构重排提供基础，并通过七聚体孔的原子细节深入了解易位过程。这些研究结果将为设计阻断炭疽毒素孔形成和转移到细胞内的新疗法提供合理的基础。

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.