biostudies-literatureChan FTMedical Research CouncilAlzheimers Research UKWellcome TrustBiotechnology and Biological Sciences Research CouncilEngineering and Physical Sciences Research Council2156-62https://www.ebi.ac.uk/biostudies/studies/S-EPMC5360231biostudies-literatureUnknown138(7)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.The AnalystProtein amyloids develop an intrinsic fluorescence signature during aggregation.PMC5360231EP/H018301/1089703ARUK-EG2012A-1BB/E019927/1MC_G1000734Bertoncini CWDobson CMKaminski Schierle GSKumita JRChan FTKaminski CFfalseProtein amyloids develop an intrinsic fluorescence signature during aggregation.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.2013-01-01T00:00:00Z2013 Apr2024-02-15T02:23:34.232Z2019-03-27T02:39:10ZS-EPMC53602312342008810.1039/c3an36798c