Amyloidophilic Molecule Interactions on the Surface of Insulin Fibrils: Cooperative Binding and Fluorescence Quenching.

Protein aggregation into insoluble fibrillar aggregates is linked to several neurodegenerative disorders, such as Alzheimer's or Parkinson's disease. Commonly used methods to study aggregation inhibition or fibril destabilization by potential drugs include spectroscopic measurements of amyloidophilic dye molecule fluorescence or absorbance changes. In this work we show the cross-interactions of five different dye molecules on the surface of insulin amyloid fibrils, resulting in cooperative binding and fluorescence quenching.