Inhibition of toxicity in the β-amyloid peptide fragment β-(25-35) using N-methylated derivatives -: A general strategy to prevent amyloid formation
Inhibition of toxicity in the β-amyloid peptide fragment β-(25-35) using N-methylated derivatives -: A general strategy to prevent amyloid formation
复制标题
DOI：
10.1074/jbc.m003554200
复制
发表时间：
2000-08-18
影响因子：
4.8
通讯作者：
Doig, AJ
中科院分区：
文献类型：
--
作者：
Hughes, E;Burke, RM;Doig, AJ
β -(25-35)是β -淀粉样蛋白的合成衍生物，β -淀粉样蛋白是一种被认为会导致阿尔茨海默病的肽。由于它具有高毒性，并形成典型的p -淀粉样蛋白的纤维聚集体，因此适合作为测试聚集抑制剂和毒性的模型。我们证明了β -(25-35)的n-甲基化衍生物，它在分离时是可溶的和无毒的，可以阻止聚集并抑制野生型肽的毒性。n -甲基化可以阻断组装淀粉样蛋白外缘的氢键。这些肽通过刚果红和硫黄素T结合、电子显微镜和3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四唑（MTT）对PC12细胞的毒性试验进行了检测。一种肽（Gly(25) n -甲基化）具有与野生型相似的特性，而五种肽对预折叠原纤维和原纤维组装有不同的影响。特别是，Gly(33) n -甲基化的β -(25-35)能够完全阻止原纤维的组装，并降低折叠前淀粉样蛋白的毒性。随着Leu(34) n甲基化，原纤维形态发生改变，毒性降低。我们认为，使用淀粉样蛋白肽和蛋白的n甲基化衍生物可以为淀粉样蛋白沉积和毒性问题提供一个通用的解决方案。
beta-(25-35) is a synthetic derivative of beta-amyloid, the peptide that is believed to cause Alzheimer's disease. As it is highly toxic and forms fibrillar aggregates typical of P-amyloid, it is suitable as a model for testing inhibitors of aggregation and toxicity. We demonstrate that N-methylated derivatives of beta-(25-35), which in isolation are soluble and non-toxic, can prevent the aggregation and inhibit the resulting toxicity of the wild type peptide. N-Methylation can block hydrogen bonding on the outer edge of the assembling amyloid, The peptides are assayed by Congo red and thioflavin T binding, electron microscopy, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) toxicity assay on PC12 cells. One peptide (Gly(25) N-methylated) has properties similar to the wild type, whereas five have varying effects on prefolded fibrils and fibril assembly. In particular, beta-(25-35) with Gly(33) N-methylated is able to completely prevent fibril assembly and to reduce the toxicity of prefolded amyloid. With Leu(34) N-methylated, the fibril morphology is altered and the toxicity reduced. We suggest that the use of N-methylated derivatives of amyloidogenic peptides and proteins could provide a general solution to the problem of amyloid deposition and toxicity.