RESUMO
The aggregation of amyloid beta (Aß) into fibrillar aggregates is a key feature of Alzheimer's disease (AD) pathology. ß-carotene and related compounds have been shown to associate with amyloid aggregates and have direct impact on the formation of amyloid fibrils. However, the precise effect of ß-carotene on the structure of amyloid aggregates is not known, which poses a limitation towards developing it as a potential AD therapeutic. In this report, we use nanoscale AFM-IR spectroscopy to probe the structure of Aß oligomers and fibrils at the single aggregate level and demonstrate that the main effect of ß-carotene towards modulating Aß aggregation is not to inhibit fibril formation but to alter the secondary structure of the fibrils and promote fibrils that lack the characteristic ordered beta structure.
