Related Experiment Video
Updated: Oct 18, 2026

Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy
Published on: September 12, 2019
Monitoring the assembly of Ig light-chain amyloid fibrils by atomic force microscopy
C Ionescu-Zanetti1, R Khurana, J R Gillespie
1Department of Physics, University of California, Santa Cruz, CA 95064, USA.
Abstract:
Aggregation of Ig light chains to form amyloid fibrils is a characteristic feature of light-chain amyloidosis, a light-chain deposition disease. A recombinant variable domain of the light chain SMA was used to form amyloid fibrils in vitro. Fibril formation was monitored by atomic force microscopy imaging. Single filaments 2.4 nm in diameter were predominant at early times; protofibrils 4.0 nm in diameter were predominant at intermediate times; type I and type II fibrils 8.0 nm and 6.0 nm in diameter, respectively, were predominant at the endpoints. The increase in number of fibrils correlated with increased binding of the fluorescent dye thioflavin T. The fibrils and protofibrils showed a braided structure, suggesting that their formation involves the winding of protofibrils and filaments, respectively. These observations support a model in which two filaments combine to form a protofibril, two protofibrils intertwine to form a type I fibril, and three filaments form a type II fibril.
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...
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
Fibril-associated Collagen
For example, the type II collagen fibrils in cartilage have covalently bound type IX fibril-associated collagens at regular intervals. Other types of fibril-associated collagens are...

