Model of an SH3 amyloid fibril as deduced from cryoEM microscopy of Saibil and coworkers (56). (a) Fibril structure showing four protofilaments and a fairly hollow interior space. (b) Side view of a single protofilament. (c and d) Model for packing of β-sheets into the fibril. Dots indicate regions of polypeptide connecting the β-sheet regions. Reproduced with permission from The EMBO Journal (56).