The Aggregation Potential of the 1-15- and 1-16-Fragments of the Amyloid β Peptide and Their Influence on the Aggregation of Aβ40

摘要

The aggregation of amyloid β (Aβ) peptide is important in Alzheimer's disease. Shorter Aβ fragments may reduce Aβ's cytotoxicity and are used in diagnostics. The aggregation of Aβ16 is controversial; Liu et al. (J. Neurosci. Res. 75:162-171, 2004) and Liao et al. (FEBS Lett. 581:1161-1165, 2007) find that Aβ16 does not aggregate and reduces Aβ's cytotoxicity, Du et al. (J. Alzheimer's Dis. 27:401-413, 2011) reports that Aβ16 aggregates and that Aβ16 oligomers are toxic to cells. Here the aggregation potential of two shorter fragments, Aβ15 and Aβ16, and their influence on Aβ40 is measured by electron paramagnetic resonance (EPR) spectroscopy and the ThioT fluorescence assay (ThioT). Continuous-wave, 9 GHz EPR measurements and ThioT results reveal that neither Aβ15 nor Aβ16 aggregate by themselves and that they do not affect Aβ40 aggregation.