Department of Medical Biophysics, Ontario Cancer Institute, University of Toronto, TMDT 4-307, 101 College Street, Toronto, Ontario, Canada.
J Mol Biol. 2010 Mar 12;396(5):1284-94. doi: 10.1016/j.jmb.2009.12.019. Epub 2009 Dec 21.
The amyloid cascade model hypothesizes that neurotoxic oligomers or aggregates formed by the Alzheimer amyloid peptide (Abeta) cause disease pathology in Alzheimer's disease. Attempted treatment strategies for Alzheimer's disease have involved either inhibiting Abeta oligomerization or aggregation, or dissolving existing aggregates. Blocking such downhill processes, however, has proved daunting. We have used a different approach that targets Abeta before the oligomerization cascade begins. We predicted that an amphipathic helix could convert Abeta into a native-like protein and inhibit initiation of oligomerization and aggregation. This idea was tested with a designed library and genetic screen. We exhaustively screened a library of semi-randomized amphipathic helical sequences, each expressed as a fusion protein with an Abeta42-yellow fluorescent protein sequence serving as a reporter for folding and solubilization. This yielded an amphipathic helix capable of initiating native-like folding in Abeta42 and preventing aggregation. This amphipathic helix has direct application to Alzheimer's disease therapy development.
淀粉样蛋白级联模型假设，阿尔茨海默病淀粉样肽 (Abeta) 形成的神经毒性寡聚体或聚集体导致疾病病理学。阿尔茨海默病的治疗策略包括抑制 Abeta 寡聚化或聚集，或溶解现有的聚集体。然而，阻止这种下坡过程被证明是艰巨的。我们采用了一种不同的方法，在寡聚级联开始之前针对 Abeta。我们预测，两亲性螺旋可以将 Abeta 转化为类似天然的蛋白质，并抑制寡聚化和聚集的起始。这一想法通过设计的文库和遗传筛选进行了测试。我们彻底筛选了一个半随机化的两亲性螺旋序列文库，每个序列都表达为与 Abeta42-黄色荧光蛋白序列融合的融合蛋白，该序列作为折叠和溶解的报告物。这产生了一种能够引发 Abeta42 中类似天然折叠并防止聚集的两亲性螺旋。这种两亲性螺旋在阿尔茨海默病治疗开发中具有直接的应用。
