Vestergaard Mun'delanji, Hamada Tsutomu, Saito Masato, Yajima Yoshifumi, Kudou Monotori, Tamiya Eiichi, Takagi Masahiro
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan.
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi City, Ishikawa 923-1292, Japan.
Biochem Biophys Res Commun. 2008 Dec 12;377(2):725-728. doi: 10.1016/j.bbrc.2008.10.072. Epub 2008 Oct 23.
Assembly of Amyloid beta (Abeta) peptides, in particular Abeta-42 is central to the formation of the amyloid plaques associated with neuro-pathologies such as Alzheimer's disease (AD). Molecular assembly of individual Abeta-42 species was observed using a simple fluorescence microscope. From the molecular movements (aka Brownian motion) of the individual peptide assemblies, we calculated a temporal evolution of the hydrodynamic radius (R(H)) of the peptide at physiological temperature and pH. The results clearly show a direct relationship between R(H) of Abeta-42 and incubation period, corresponding to the previously reported peptide's aggregation kinetics. The data correlates highly with in solution-based label-free electrochemical detection of the peptide's aggregation, and Abeta-42 deposited on a solid surface and analysed using atomic force microscopy (AFM). To the best of our knowledge, this is the first analysis and characterisation of Abeta aggregation based on capturing molecular trails of individual assemblies. The technique enables both real-time observation and a semi-quantitative distribution profile of the various stages of Abeta assembly, at microM peptide concentration. Our method is a promising candidate for real-time observation and analysis of the effect of other pathologically-relevant molecules such as metal ions on pathways to Abeta oligomerisation and aggregation. The method is also a promising screening tool for AD therapeutics that target Abeta assembly.
β-淀粉样蛋白（Aβ）肽的组装，尤其是Aβ-42的组装，是与神经病理学如阿尔茨海默病（AD）相关的淀粉样斑块形成的核心。使用简单的荧光显微镜观察了单个Aβ-42分子的组装。根据单个肽组装体的分子运动（即布朗运动），我们计算了该肽在生理温度和pH下流体动力学半径（R(H)）的时间演变。结果清楚地表明Aβ-42的R(H)与孵育期之间存在直接关系，这与先前报道的肽的聚集动力学一致。这些数据与基于溶液的无标记电化学检测肽聚集以及沉积在固体表面并使用原子力显微镜（AFM）分析的Aβ-42高度相关。据我们所知，这是首次基于捕获单个组装体的分子轨迹对Aβ聚集进行分析和表征。该技术能够在微摩尔肽浓度下实时观察Aβ组装各个阶段的半定量分布情况。我们的方法有望用于实时观察和分析其他病理相关分子（如金属离子）对Aβ寡聚化和聚集途径的影响。该方法也是一种有前景的针对Aβ组装的AD治疗药物筛选工具。
