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利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 蛋白质-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)和前序列多肽酶(PREP)。IDE在胰岛素和淀粉样β蛋白的清除中起着关键作用，这两种多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β蛋白，因此它在维持线粒体完整性方面起着关键作用。我们建议用SAXS来研究这些酶的齐聚、构象开关和底物结合。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。我们实验室已经解决了炭疽肿胀因子(EF)、花青素O(AlO)和百日咳蓝百日咳的晶体结构。EF是一种腺酰环化酶毒素，它结合炭疽保护性抗原使其进入细胞，并结合钙调蛋白使其催化激活。百日咳还需要钙调素的结合才能使其催化激活。然而，CyaA具有与EF不同的钙调蛋白结合部位。对于Alo，它需要齐聚以获得成孔活性，并与细胞表面受体结合。此外，炭疽菌还分泌大约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。SAXS将被用来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.