PDF(Pubmed)
Abstract：
Amyloid β (Aβ) oligomers are the most neurotoxic forms of Aβ, and Aβ(1-42) is the prevalent Aβ peptide found in the amyloid plaques of Alzheimer\'s disease patients. Aβ(25-35) is the shortest peptide that retains the toxicity of Aβ(1-42). Aβ oligomers bind to calmodulin (CaM) and calbindin-D28k with dissociation constants in the nanomolar Aβ(1-42) concentration range. Aβ and histidine-rich proteins have a high affinity for transition metal ions Cu2+, Fe3+ and Zn2+. In this work, we show that the fluorescence of Aβ(1-42) HiLyteTM-Fluor555 can be used to monitor hexa-histidine peptide (His6) interaction with Aβ(1-42). The formation of His6/Aβ(1-42) complexes is also supported by docking results yielded by the MDockPeP Server. Also, we found that micromolar concentrations of His6 block the increase in the fluorescence of Aβ(1-42) HiLyteTM-Fluor555 produced by its interaction with the proteins CaM and calbindin-D28k. In addition, we found that the His6-tag provides a high-affinity site for the binding of Aβ(1-42) and Aβ(25-35) peptides to the human recombinant cytochrome b5 reductase, and sensitizes this enzyme to inhibition by these peptides. In conclusion, our results suggest that a His6-tag could provide a valuable new tool to experimentally direct the action of neurotoxic Aβ peptides toward selected cellular targets.
摘要：
淀粉样蛋白β（Aβ）寡聚体是Aβ的最神经毒性形式，Aβ(1-42)是在阿尔茨海默病患者的淀粉样斑块中发现的普遍的Aβ肽。Aβ(25-35)是保留Aβ(1-42)毒性的最短肽。Aβ寡聚体与钙调蛋白（CaM）和钙结合蛋白-D28k结合，解离常数在纳摩尔Aβ（1-42）浓度范围内。Aβ和富含组氨酸的蛋白质对过渡金属离子Cu2+具有很高的亲和力，Fe3+和Zn2+。在这项工作中,我们表明，Aβ（1-42）HiLyteTM-Fluor555的荧光可用于监测六组氨酸肽（His6）与Aβ（1-42）的相互作用。MDockPePServer产生的对接结果也支持His6/Aβ（1-42）复合物的形成。此外，我们发现His6的微摩尔浓度阻断了Aβ（1-42）HiLyteTM-Fluor555与蛋白质CaM和钙结合蛋白-D28k相互作用产生的荧光增加。此外,我们发现His6标签为Aβ（1-42）和Aβ（25-35）肽与人重组细胞色素b5还原酶的结合提供了高亲和力位点，并使这种酶对这些肽的抑制作用敏感。总之,我们的结果表明,His6-tag可以提供一种有价值的新工具,通过实验指导神经毒性Aβ肽对选定的细胞靶标的作用.
