Beta Secretase Inhibition for Treating Alzheimer's Disease

描述（由申请人提供）：Memapsin 2 （β -分泌酶，BACE）是一种蛋白酶，启动β -淀粉样蛋白前体蛋白（APR）的裂解，导致β淀粉样蛋白（Abeta）的产生。它是开发抗阿尔茨海默病（AD）抑制剂药物的主要靶点。了解memapsin 2的活性、结构和功能是抑制剂设计和测试的基础。在这个项目的最后5年里，我们建立了实验，完成了动力学特异性分析，确定了晶体结构，并设计了几代抑制剂，这些抑制剂在转基因AD小鼠中获得了高效，相对较小的尺寸，相对于选定的人类天冬氨酸蛋白酶，细胞通透性和抑制β产生的良好选择性。在本项目的下一阶段，我们建议进一步研究memapsin 2的结构-功能信息，以获得与抑制剂开发相关的信息，获得更好的药物样性质，探索新的化学合成抑制剂，并针对新发现的memapsin 2亚位开发非过渡态抑制剂。目标是：目标1；深入开展memapsin 2的结构-功能研究，进一步设计基于结构的抑制剂。我们打算研究新的配体与memapsin 2亚位点S7、S6和S5的结合亲和力，活性位点间隙“瓶颈”残基对抑制剂亚位点特异性的作用，memapsin 2抑制剂的细胞抑制作用以及memapsin 2抑制剂药物的治疗局限性。目标2。设计和测试具有更好体内效力和选择性的过渡态memapsin 2抑制剂。我们建议优化拟肽抑制剂的配体结合位点相互作用，设计和合成新的非肽基高亲和力配体、模板和支架，结合碱性胺和亲脂功能以有效吸收和血脑屏障运输，并提高小分子非肽基抑制剂的效价。目标3。开发和测试针对蛋白酶新位点的新型膜蛋白酶2抑制剂。我们建议设计和测试一类新的非过渡态抑制剂，针对3个独特的亚位，P7， P6和P5。我们将使用基于结构的设计周期来开发小的、有效的和选择性的新抑制剂。

DESCRIPTION (provided by applicant): Memapsin 2 (beta-secretase, BACE) is the protease that initiated the cleavage of beta-amyloid precursor protein (APR) leading to the production of amyloid-beta (Abeta). It is the major target for the development of inhibitor drugs against Alzheimer's disease (AD). The understanding on the activity, structure and function of memapsin 2 is fundamental for inhibitor design and testing. During the last 5 years of this project, we have established assays, completed kinetic specificity analysis, determined crystal structures and designed generations of inhibitors that have attained high potency, relatively small size, and good selectivity vs. chosen human aspartic proteases, cell permeability and inhibition of Abeta production in transgenic AD mice. For the next period of this project, we propose to further probe memapsin 2 for structure-function information relevant to inhibitor development, to acquire better drug-like properties, to explore new chemistry for inhibitor synthesis and to develop non-transition state inhibitors against newly discovered subsites of memapsin 2. The Aims are: Aim 1. To carry out in-depth memapsin 2 structure-function studies for further structure-based inhibitor design. We propose to investigate the binding affinity of new ligands toward memapsin 2 subsites S7, S6 and S5, the role of active-site cleft 'bottleneck' residues on the inhibitor subsite specificity, cellular inhibition by memapsin 2 inhibitors and the therapeutic limits of memapsin 2 inhibitor drugs. Aim 2. Design and testing transition-state memapsin 2 inhibitors with better in vivo potency and selectivity. We propose to optimize ligand-binding site interactions of lead peptidomimetic inhibitors, design and synthesize novel nonpeptidyl high-affinity ligands, templates and scaffolds, incorporate basic amines and lipophilic functionalities for effective absorption and BBB transport, and improve potency of small molecule nonpeptidyl inhibitors. Aim 3. To develop and test novel memapsin 2 inhibitors targeting to new sites in the protease. We propose to design and test a new class of non-transition state inhibitors targeted at 3 unique subsites, P7, P6 and P5. We will use structure-based design cycle to develop small, potent and selective new inhibitors.