Alzheimer disease is diagnosed postmortem by the density and spatial distribution of β-amyloid plaques and tau-bearing neurofibrillary tangles. The major protein component of each lesion adopts cross-β-sheet conformation capable of binding small molecules with submicromolar affinity. In many cases, however, Alzheimer pathology overlaps with Lewy body disease, characterized by the accumulation of a third cross-β-sheet […]