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.
Engineering E. coli cell surface in order to develop a one-step purification method for recombinant proteins