Protein amyloids develop an intrinsic fluorescence signature during aggregation

FIONA T.S. CHAN; GABRIELE S. KAMINSKI SCHIERLE; JANET R. KUMITA; CARLOS W. BERTONCINI; CHRISTOPHER M. DOBSON; CLEMENS F. KAMINSKI

ANALYST

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2013 vol. 138 p. 2156 - 2162

0003-2654

We report observations of an intrinsic fluorescence in the visible range, which develops during the aggregation of a range of polypeptides, including the disease-related human peptides amyloid-β(1–40) and (1–42), lysozyme and tau. Characteristic fluorescence properties such as the emission lifetime and spectra were determined experimentally. This intrinsic fluorescence is independent of the presence of aromatic side-chain residues within the polypeptide structure. Rather, it appears to result from electronic levels that become available when the polypeptide chain folds into a cross-β sheet scaffold similar to what has been reported to take place in crystals. We use these findings to quantify protein aggregation in vitro by fluorescence imaging in a label-free manner.