Goldsbury Claire, Green Janelle
Max-Planck-Unit for Structural Molecular Biology, Hamburg, Germany.
Methods Mol Biol. 2005;299:103-28. doi: 10.1385/1-59259-874-9:103.
The atomic force microscope (AFM) images the topography of biological structures adsorbed to surfaces with nanometer to angstrom scale resolution. Amyloid-like fibrils and oligomers can be imaged in buffer solutions, allowing the samples to retain physiological-like properties while temporal changes in structure are monitored, e.g., the elongation of fibrils or the growth of single oligomers. These qualities distinguish AFM from conventional imaging techniques of comparable resolution, i.e., electron microscopy (EM). However, AFM is limited in that the specimen must be firmly attached to a solid support for measurement and that time-lapse imaging of individual assemblies can thus only be achieved for fibrils and oligomers growing on this support. Nevertheless, AFM has provided several insights into the in vitro assembly mechanism and structures of amyloid-like fibrils. The first section of this chapter provides a methodological introduction to AFM, whilst the second details the application of this technique to the investigation of amyloidogenic proteins, specifically amylin and amyloid-beta (Abeta) peptides.
原子力显微镜（AFM）能够以纳米到埃的尺度分辨率对吸附在表面的生物结构的形貌进行成像。淀粉样纤维和寡聚体可以在缓冲溶液中成像，使得样品在监测结构的时间变化（例如纤维的伸长或单个寡聚体的生长）时能够保持类似生理的特性。这些特性使AFM有别于具有可比分辨率的传统成像技术，即电子显微镜（EM）。然而，AFM的局限性在于，样品必须牢固地附着在固体支持物上进行测量，因此只能对生长在该支持物上的纤维和寡聚体进行单个组装体的延时成像。尽管如此，AFM已经为体外淀粉样纤维的组装机制和结构提供了一些见解。本章的第一部分提供了AFM的方法学介绍，而第二部分详细阐述了该技术在淀粉样蛋白生成蛋白，特别是胰岛淀粉样多肽和β-淀粉样蛋白（Aβ）肽研究中的应用。
