Affiliations: [a] Institute of Protein Research, Russian Academy of Science, Pushchino, Moscow Region, Russia | [b] State Research Center for Applied Microbiology & Biotechnology, Obolensk, Serpukhov District, Moscow Region, Russia
Correspondence:
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Correspondence to: Oxana V. Galzitskaya, Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia. Tel.: +7 4967 318275; Fax: +7 4967 318435; ogalzit@vega.protres.ru
Abstract: The aim of this study was to investigate the process of amyloidogenesis of amyloid-β (Aβ)42 peptide, by means of fluorescence spectroscopy, electron microscopy, X-ray diffraction, and mass spectrometry. It has been repeatedly reported in the literature that the process of fibril formation by Aβ
42 peptide depends considerably not only upon the specific conditions (ionic conditions, pH, temperature, mixing, etc.), as well as the manufacturing route (synthetic or recombinant), but also on the methods of synthesis and purification. We have, for the first time, systematically analyzed samples of Aβ
42 peptide supplied by five different companies (Anaspec, Invitrogen, Enzo, Sigma-Aldrich, and SynthAssist) and obtained evidence of significant variability, including lot to lot variations. All studied samples formed amyloid-like fibrils at pH3-6, and the fibrils contained cross-β structures. Samples from Anaspec, Invitrogen, and Enzo formed one particular type of amyloid-like fibrils, while the samples from Sigma-Aldrich and SynthAssist formed another distinct type of fibrils. The observed polymorphism emphasizes the capacity of the Aβ
42 peptide to act as a prion agent with varying structural characteristics. The presented data have allowed us to propose a possible mechanism of formation of amyloid-like fibrils.
Keywords: Aβ
42 peptide, Alzheimer’s disease, amyloid fibril, electron microscopy, mass spectroscopy, oligomer, prion-like behavior, protofibril
