Related Experiment Video
Updated: May 31, 2026

Analysis of β-Amyloid-induced Abnormalities on Fibrin Clot Structure by Spectroscopy and Scanning Electron Microscopy
Published on: November 30, 2018
AFM study of glucagon fibrillation via oligomeric structures resulting in interwoven fibrils
Mingdong Dong1, Mads Bruun Hovgaard, Sailong Xu
1Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, DK-8000 Aarhus C, Denmark. Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark.
Abstract:
Glucagon is a 29-residue amphiphatic hormone involved in the regulation of blood glucose levels in conjunction with insulin. In concentrated aqueous solutions, glucagon spontaneously aggregates to form amyloid fibrils, destroying its biological activity. In this study we utilize the atomic force microscope (AFM) to elucidate the fibrillation mechanism of glucagon at the nanoscale under acidic conditions (pH 2.0) by visualizing the nanostructures of fibrils formed at different stages of the incubation. Hollow disc-shaped oligomers form at an early stage in the process and subsequently rearrange to more solid oligomers. These oligomers co-exist with, and most likely act as precursors for, protofibrils, which subsequently associate to form at least three different classes of higher-order fibrils of different heights. A repeat unit of around 50 nm along the main fibril axis suggests a helical arrangement of interwoven protofibrils. The diversity of oligomeric and fibrillar arrangements formed at pH 2.0 complements previous spectroscopic analyses that revealed that fibrils formed under different conditions can differ substantially in stability and secondary structure.
Related Concept Videos
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Studying the Cytoskeleton
Protein and Protein Structure
A protein's shape is critical to its function. For example, an enzyme can...
Formation of Higher-order Actin Filaments
The high-order actin networks...

