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Capillary electrophoresis for the analysis of the effect of sample preparation on early stages of Aβ 1–40 aggregation
Author(s) -
Pryor N. Elizabeth,
Moss Melissa A.,
Hestekin Christa N.
Publication year - 2014
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201400012
Subject(s) - oligomer , chemistry , monomer , protein aggregation , capillary electrophoresis , chromatography , fibril , matrix (chemical analysis) , polymer , biochemistry , organic chemistry
Aggregation of the amyloid‐β protein (Aβ) contributes to the neurodegeneration characteristic of Alzheimer's disease. Of particular importance are the early stages of aggregation, which involve the formation of soluble oligomers and protofibrils. In these studies, we demonstrate the potential for CE with UV detection using a polyethylene oxide separation matrix to identify the evolution of various oligomeric species of Aβ 1–40 . To demonstrate the efficacy of this technique, UV‐CE was utilized to compare two methods commonly used to prepare Aβ for aggregation experiments and their effect on the formation of early aggregates. SEC‐purified Aβ 1–40 initially contained more small species, including monomer, than did freshly dissolved Aβ 1–40 pretreated with hexafluoroisopropanol. Strikingly, the lag time to oligomer formation for SEC‐isolated Aβ 1–40 samples was ∼23 h shorter compared to freshly dissolved Aβ 1–40 samples. Furthermore, oligomers formed from the aggregation of SEC‐purified Aβ 1–40 persisted within solution for a longer period of time. These results indicate that the initial sample preparation has a drastic influence on the early stages of Aβ 1–40 aggregation. This is the first report of the use of UV‐CE with a separation matrix to study the effect of sample preparation on early aggregation of Aβ 1–40 . UV‐CE was also used in parallel with dot blot analysis and inhibitory compounds to discern structural characteristics of individual oligomer peaks, demonstrating the capacity of UV‐CE as a complimentary technique to further understand the aggregation process.