αB-crystallin affects the morphology of Aβ(1-40) aggregates

Abstract

αB-crystallin (ABC) is a human small heat shock protein that is strongly linked to Alzheimer’s disease (AD). In vitro, it can inhibit the aggregation and amyloid formation of a range of proteins including Aβ(1-40), a primary component of AD amyloid plaques. Despite the strong links, the mechanism by which ABC inhibits amyloid formation has remained elusive, in part due to the notorious irreproducibility of aggregation assays involving preparations of Aβ-peptides of native sequence. Here, we present a recombinant expression protocol to produce native Aβ(1-40), devoid of any modifications or exogenous residues, with yields up to 4 mg/L E. coli. This material provides highly reproducible aggregation kinetics and, by varying the solution conditions, we obtain either highly ordered amyloid fibrils or more disordered aggregates.