Fast purification of recombinant monomeric amyloid-β fromE. coliand amyloid-β-mCherry aggregates from mammalian cells

The Alzheimer’s disease related peptide, Amyloid-beta (Aβ)1-40 and 1-42, has proven difficult to be purified as a recombinant monomeric protein due its expression in E. coli leading to the formation of insoluble inclusion bodies and its tendency to quickly form insoluble aggregates. A vast array of methods have been used so far, yet many have pitfalls, such as the use of tags for ease of Aβ isolation, the formation of Aβ multimers within the time frame of extraction or the need to reconstitute Aβ from a freeze dried state. Here, we present a rapid protocol to produce highly pure and monomeric recombinant Aβ using a one-step ion exchange purification method and to label the peptide using a maleimide dye. The solublisation and purification steps take only three hours. We also present a protocol for the isolation of Aβ-mCherry from mammalian cells. Highlights Purification of untagged, monomeric recombinant Aβ from E. coli . A fast protocol; 6 hours for E. coli growth and Aβ expression, 2 hours to clean inclusion bodies, 45 mins to solublise and purify the peptide. No freeze drying step that can lead to oligomer formation. Purification of fluorescent Aβ-mCherry from mammalian cells.