Fibril self-assembly of amyloid-spider silk block polypeptides.

Because of their association with debilitating diseases and their potential applications in developing novel bionanomaterials, highly ordered amyloid fibrils have recently received considerable attention. While many studies have thus far focused on amyloid fibrils made with short peptides containing just one steric zipper-forming segment of native amyloid proteins, the self-assembly of proteins containing multiple steric zipper-forming segments has been rarely explored. Here we develop a strategy to create four block polypeptides, each containing 16 repeats of a zipper-forming segment from four different amyloid morphological classes. All four block polypeptides self-assemble into fibrils that display the cross-fi structure characteristic of amyloids. These amyloid spider silk block polypeptides displayed fast self-assembly kinetics, and their fibrils exhibited high thermal stability. These novel synthetic amyloids provide insights into the self-assembly of proteins containing multiple zipper-forming segments, and our approach of creating block polypeptide fibrils could be used to expand the capability of amyloid-based bionanomaterials.