Molecular Probes for Alzheimer's Gamma-Secretase

描述：（申请人提供）淀粉样β蛋白沉积 (An)是阿尔茨海默病发病机制中的早期和不变事件 (AD)以及两种从淀粉样前体蛋白中切割Abeta的蛋白酶 (APP)β-和γ-分泌酶被认为是重要的治疗靶点。 γ-分泌酶在单跨膜内催化不寻常的蛋白水解 APP的区域，并且这种切割需要多跨膜早老素。 早老素中超过60种不同的错义突变导致AD，这些错义突变导致AD。 突变改变γ-分泌酶的活性， Abeta的42个残基的原纤维形成变体（Abeta42）。抑制剂分析， 分子模拟和诱变研究表明，γ-分泌酶具有 一种乙酰基蛋白酶的性质，可以催化一种不寻常的膜内 蛋白水解此外，早老蛋白中两个保守的跨膜转运体， 是γ-分泌酶活性所必需的，过渡态类似物抑制剂 的γ-分泌酶直接和特异性地结合到早老素。综合起来看， 这些结果有力地表明早老素本身是γ-分泌酶， 新的膜内切割乙酰基蛋白酶。目前的目标 建议是了解γ-分泌酶活性位点的地形， 鉴定在活性位点中或附近的早老素残基，以及 开发用于研究γ-分泌酶在体内的正常作用及其 作为AD治疗靶点的潜力。γ-分泌酶的空间限制 通过系统地改变凹穴S3至S4 ′的尺寸， 过渡态类似物抑制剂中的相应取代基。的 有效化合物的发现将允许亲和基质的发展 用于纯化该蛋白酶和鉴定相关的 辅因子早老蛋白中与这种蛋白相互作用的特定区域 抑制剂（即，活动部位内或附近的部件）将通过 光亲和标记特异性标记的跨膜残基 早老素将提供令人信服的证据， 绝佳的价钱最后，这些过渡态模拟物的非肽类似物将被 利用组合化学作为一种策略的一部分， 整体阻断γ-分泌酶活性的代谢稳定化合物 有机体

DESCRIPTION: (Provided by Applicant) Deposition of the amyloid-beta protein (An) is an early and invariant event in the pathogenesis of Alzheimer's disease (AD), and the two proteases that cut Abeta from the amyloid precursor protein (APP), beta- and y-secretases, are considered important therapeutic targets. y-Secretase catalyzes an unusual proteolysis within the single transmembrane region of APP, and this cleavage requires the multi-transmembrane presenilins. More than 60 different missense mutations in presenilins cause AD, and these mutations alter y-secretase activity to increase levels of a highly fibrillogenic 42-residue variant of Abeta (Abeta42). Inhibitor profiling, molecular modeling, and mutagenesis studies reveal that y-secretase has properties of an aspartyl protease and may catalyze an unusual intramembranous proteolysis. Moreover, two conserved transmembrane aspartates in presenilins are required for y-secretase activity, and transition-state analogue inhibitors of y-secretase bind directly and specifically to presenilins. Taken together, these results strongly suggest that presenilins themselves are y-secretases, novel intramembrane-cleaving aspartyl proteases. The objectives of the present proposal are to understand the topography of the y-secretase active site, to identify presenilin residues that are in or near the active site, and to develop compounds for studying the normal role of y-secretase in vivo and its potential as a therapeutic target for AD. The steric limits of y-secretase pockets S3 through S4' will be probed by systematically varying the size of the corresponding substituents in transition-state analogue inhibitors. The discovery of potent compounds would allow the development of affinity matrices for the purification of this protease and identification of associated cofactors. Specific regions within presenilins that interact with such inhibitors (i.e., parts in or near the active site) will be identified by photoaffinity labeling. The specific labeling of transmembrane residues of presenilins would provide compelling evidence for an intramembranous active site. Finally, nonpeptide analogues of these transition-state mimics will be developed using combinatorial chemistry as part of a strategy to identify metabolically stable compounds that block y-secretase activity in whole organisms.