Inhibition of beta-amyloid aggregation by fluorescent dye labels

The fluorescence decay of beta-amyloid’s (Ab) intrinsic fluorophore tyrosine has been used for sensing the oligomer formation of dye-labelled Ab monomers and the results compared with previously studied oligomerization of the non-labelled Ab peptides. It has been demonstrated that two different sized, covalently bound probes 7-diethylaminocoumarin-3-carbonyl and Hilyte Fluor 488 (HLF), alter the rate and character of oligomerization to different extents. The ability of HLF to inhibit formation of highly ordered structures containing beta-sheets was also shown. The implications of our findings for using fluorescence methods in amyloidosis research are discussed and the advantages of this auto-fluorescence approach highlighted.