Transient small molecule interactions kinetically modulate amyloid β peptide self‐assembly

Small organic molecules, like Congo red and lacmoid, have been shown to modulate the self-assembly of the amyloid β peptide (Aβ). Here, we show that Aβ forms NMR invisible non-toxic co-aggregates together with lacmoid as well as Congo red. We find that the interaction involves two distinct kinetic processes and at every given time point only a small fraction of Aβ is in the co-aggregate. These weak transient interactions kinetically redirect the aggregation prone Aβ from self-assembling into amyloid fibrils. These findings suggest that even such weak binders might be effective as therapeutics against pathogenic protein aggregation.