Fluorescent and luminescent fusion proteins for analyses of amyloid beta peptide aggregation

The amyloid beta (A β ) peptide is regarded as a causative agent of Alzheimer's disease. In this study, fluorescent and luminescent fusion proteins were constructed to analyze A β aggregation. A system was developed to monitor changes in luminescence that provides information about A β aggregation. In the presence of monomeric A β , the fusion protein exhibits higher luminescence intensity, and the luminescence intensity is diminished after aggregation of the fusion protein and A β . In contrast, the fluorescence is sustained in the presence of A β . In the absence of A β , the fusion protein self‐aggregates, and its luminescence and fluorescence are quenched, thus decreasing the background fluorescence and enhancing the detection of A β inside and outside the cells. The ratio of the luminescence intensity to the fluorescence intensity would allow the aggregation degrees of A β to be distinguished. This study would be a promising method for analyzing the aggregation state of a particular amyloid protein/peptide (monomer, oligomer, or fibril), as well as the distribution of the amyloid protein/peptide within and at the cell surface, by using a single fusion protein. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.