Copper-dependent inhibition of human cytochrome c oxidase by a dimeric conformer of amyloid-β1-42
Copper-dependent inhibition of human cytochrome c oxidase by a dimeric conformer of amyloid-β1-42
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DOI：
10.1523/jneurosci.4276-04.2005
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发表时间：
2005-01-19
影响因子：
5.3
通讯作者：
Trounce, IA
中科院分区：
文献类型：
--
作者：
Crouch, PJ;Blake, R;Trounce, IA
在阿尔茨海默病发病机制的研究中，越来越多地关注细胞内淀粉样蛋白β（Abeta）的产生和毒性机制。在这里，我们研究了42个氨基酸的Abeta肽（Abeta（1-42））对人线粒体中电子传递链酶复合物活性的抑制潜力。我们发现合成的Abeta（1-42）以剂量依赖性方式特异性抑制末端复合物细胞色素c氧化酶（考克斯），该方式依赖于Cu 2+的存在和Abeta（1-42）溶液的特异性“老化”。当使用在30 ℃下老化3 - 6小时的Abeta（1-42）溶液时，出现最大的考克斯抑制。Abeta（1-42）介导的考克斯抑制水平随着老化时间增加而增加，直到接近6 h，然后随着继续老化到48 h而进行性下降。未修饰蛋白质的光诱导交联，随后进行SDS-PAGE分析，揭示了二聚体Abeta作为唯一的Abeta种类，提供与观察到的考克斯抑制的显著时间相关性。对阿尔茨海默病模型小鼠（Tg 2576）的脑和肝脏的分析显示，脑线粒体部分内存在丰富的Abeta免疫反应性。我们的数据表明，内源性Abeta与脑线粒体相关，Abeta（1-42），可能在其二聚体构象，是一种有效的考克斯抑制剂，但只有在Cu 2+存在时。我们的结论是，铜2+依赖性β介导的抑制考克斯可能是一个重要的贡献者在阿尔茨海默氏病的神经退行性变的过程。
In studies of Alzheimer's disease pathogenesis there is an increasing focus on mechanisms of intracellular amyloid-beta (Abeta) generation and toxicity. Here we investigated the inhibitory potential of the 42 amino acid Abeta peptide (Abeta(1-42)) on activity of electron transport chain enzyme complexes in human mitochondria. We found that synthetic Abeta(1-42) specifically inhibited the terminal complex cytochrome c oxidase (COX) in a dose-dependent manner that was dependent on the presence of Cu2+ and specific "aging" of the Abeta(1-42) solution. Maximal COX inhibition occurred when using Abeta(1-42) solutions aged for 3 - 6 h at 30 degreesC. The level of Abeta(1-42)-mediated COX inhibition increased with aging time up to similar to 6 h and then declined progressively with continued aging to 48 h. Photo-induced cross-linking of unmodified proteins followed by SDS-PAGE analysis revealed dimeric Abeta as the only Abeta species to provide significant temporal correlation with the observed COX inhibition. Analysis of brain and liver from an Alzheimer's model mouse (Tg2576) revealed abundant Abeta immunoreactivity within the brain mitochondria fraction. Our data indicate that endogenous Abeta is associated with brain mitochondria and that Abeta(1-42), possibly in its dimeric conformation, is a potent inhibitor of COX, but only when in the presence of Cu2+. We conclude that Cu2+-dependent Abeta-mediated inhibition of COX may be an important contributor to the neurodegeneration process in Alzheimer's disease.