A robust and efficient production and purification procedure of recombinant Alzheimers disease methionine-modified amyloid-β peptides

Abstract

An improved production and purification method for Alzheimer's disease related methioninemodified amyloid-β 1-40 and 1-42 peptides is proposed, taking advantage of the formation of inclusion body in Escherichia coli. A Thioflavin-S assay was set-up to evaluate inclusion body formation during growth and optimize culture conditions for amyloid-β peptides production. A simple and fast purification protocol including first the isolation of the inclusion bodies and second, two cycles of high pH denaturation/neutralization combined with an ultrafiltration step on 30-kDa cut-off membrane was established. Special attention was paid to purity monitoring based on a rational combination of UV spectrophotometry and SDS-PAGE analyses at the various stages of the process. It revealed that this chromatographyfree protocol affords good yield of high quality peptides in term of purity. The resulting peptides were fully characterized and are appropriate models for highly reproducible in vitro aggregation studies.