X-ray crystallographic structures of trimers and higher-order oligomeric assemblies of a peptide derived from Aβ(17-36).

A peptide derived from Aβ17-36 crystallizes to form trimers that further associate to form higher-order oligomers. The trimers consist of three highly twisted β-hairpins in a triangular arrangement. Two trimers associate face-to-face in the crystal lattice to form a hexamer; four trimers in a tetrahedral arrangement about a central cavity form a dodecamer. These structures provide a working model for the structures of oligomers associated with neurodegeneration in Alzheimer's disease.