Formation of mixed fibrils demonstrates the generic nature and potential utility of amyloid nanostructures

The aggregation of proteins and peptides in the form of stable and highly ordered amyloid fibrils is most commonly associated with pathological conditions such as Alzheimer's disease and the transmissible spongiform encephalopathies. The involvement of only a handful of proteins in amyloid formation in vivo has commonly been thought of as the result of some unusual conformational characteristic of the sequences of the proteins involved. Recent evidence has however suggested that the formation of these highly ordered structures is a generic process arising from the fundamental physicochemical properties of the polypeptide chain. In this study, we have shown that we can incorporate short peptides into amyloid fibrils assembled from unrelated peptides and from a full-length protein. This result provides compelling evidence that amyloid fibril assembly is a fundamental property of polypeptide chains. We have also demonstrated by doping with fluorescently labeled peptides that the fibrils can be modified to incorporate unusual functional groups, suggesting the possibility of the production of a wide range of novel nanomaterials with potentially important properties.