SAXS OF THE COMPLEX OF ANTHRAX TOXINS AND HUMAN INSULIN DEGRADING ENZYME

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 蛋白质相互作用是控制多种生物功能的过程。我们将使用SAXS通过研究人类蛋白酶和细菌毒素来解决溶液中复杂的蛋白质-蛋白质相互作用。首先，我们将研究两种人类金属蛋白酶，胰岛素降解酶（IDE）和前序列肽酶（PreP）。IDE在清除胰岛素和β淀粉样蛋白中起着关键作用，这两种肽分别对糖尿病和阿尔茨海默病的进展至关重要。PreP降解线粒体前序列和淀粉样蛋白β，因此它在维持线粒体完整性方面发挥关键作用。我们建议用小角X射线散射来研究这些酶的寡聚化、构象转换和底物结合。第二组蛋白质是由炭疽杆菌和百日咳杆菌分泌的细菌毒素，百日咳杆菌是炭疽和百日咳的病原体。本实验室已解析了炭疽水肿因子（EF）、蒽溶素O（ALO）和百日咳CyaA的晶体结构。EF是一种腺苷酸环化酶毒素，其结合炭疽保护性抗原用于其细胞进入并结合钙调蛋白用于其催化活化。百日咳CyaA还需要钙调蛋白的结合以进行其催化活化。然而CyaA具有不同于EF的钙调素结合位点。对于ALO，它需要寡聚化以实现其成孔活性以及与细胞表面受体结合。此外，炭疽菌分泌约400种蛋白质，我们选择了其中的几种脂肪酶和蛋白酶来研究它们的功能。小角X射线散射将用于获得这些毒素与其伴侣蛋白相互作用的新见解。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Protein-protein interaction is a process that controls the diverse biological functions. We will use SAXS to address the complex protein-protein interactions in solution by studying human proteases and bacterial toxins. First, we will study two human metalloproteases, insulin degrading enzyme (IDE) and presequence peptidase (PreP). IDE plays a key role in the clearance of insulin and amyloid beta, peptides vital for the progression of diabetes and Alzheimer¿s disease, respectively. PreP degrades mitochondrial presequences and amyloid beta so that it plays a key role to maintain integrity of mitochondria. We propose to use SAXS on study the oligomerization, the conformational switch, and substrate binding of these enzymes. Second set of proteins are bacterial toxins secreted by Bacillus anthracis, and Bordetella pertussis, the etiologic agent for anthrax and whooping cough. Our lab has solved the crystal structures of anthrax edema factor (EF), anthrolysin O (ALO), and pertussis CyaA. EF is an adenylyl cyclase toxin that binds anthrax protective antigen for its cell entrance and binds calmodulin for its catalytic activation. Pertussis CyaA also requires the binding of calmodulin for its catalytic activation. However CyaA has the calmodulin-binding site distinct from that of EF. For ALO, it needs to oligomerize for its pore-forming activity as well as binds to cell surface receptor. In addition, anthrax bacteria secrete approximately 400 proteins and of those, we have chosen several lipases and proteases to study their functions. SAXS will be used to gain the new insights for the interaction of these toxins with their partner proteins.