Goldsbury C, Kistler J, Aebi U, Arvinte T, Cooper G J
School of Biological Sciences, University of Auckland, New Zealand.
J Mol Biol. 1999 Jan 8;285(1):33-9. doi: 10.1006/jmbi.1998.2299.
Late-onset diabetes is typically associated with amyloid deposits of fibrillar amylin in the pancreatic islets. Aqueous synthetic human amylin spontaneously forms polymorphic fibrils in vitro, and this system was used to examine the dynamics of fibril assembly. By time-lapse atomic force microscopy (AFM), the growth of individual amylin fibrils on a mica surface was observed over several hours. Prominent was the assembly of a protofibril with an elongation rate in these experiments of 1.1(+/-0.5) nm/minute. The assembly of higher order polymorphic fibrils was also observed. Growth of the protofibrils was bidirectional, i.e. it occurred by elongation at both ends. This ability of AFM to continuously monitor growth, directionality, and changes in morphology for individual fibrils, provides a significant advantage over spectroscopy-based bulk methods which average the growth of many fibrils and typically require 100 to 1000-fold more protein. The time-lapse AFM procedure used for human amylin here is thus likely to be applicable to fibril formation from other amyloid proteins and peptides.
迟发性糖尿病通常与胰岛中纤维状胰岛淀粉样多肽的淀粉样沉积物有关。合成人胰岛淀粉样多肽在水溶液中可在体外自发形成多态性纤维，该系统用于研究纤维组装的动力学。通过延时原子力显微镜（AFM），在数小时内观察了云母表面单个胰岛淀粉样多肽纤维的生长情况。在这些实验中，原纤维的组装很明显，其伸长速率为1.1（±0.5）nm/分钟。还观察到了高阶多态性纤维的组装。原纤维的生长是双向的，即在两端都通过伸长进行。与基于光谱的大量方法相比，AFM能够连续监测单个纤维的生长、方向性和形态变化，具有显著优势，基于光谱的大量方法对许多纤维的生长进行平均，通常需要的蛋白量多100到1000倍。因此，这里用于人胰岛淀粉样多肽的延时AFM方法可能适用于其他淀粉样蛋白和肽的纤维形成。
