An Electrospray Ionization Mass Spectrometric Study of Iron Binding to Amyloid-β Peptides

Abstract

Iron and other metal ions appear to play an important role in protein aggregation and are, therefore, likely to provide a link between protein aggregation and oxidative damage. This work reports on iron binding to the amyloid-β peptide (Aβ1–40), which affords a very specific electrospray ionization mass spectrometric (MS) spectrum. Both MS and tandem MS studies confirmed that the amyloid β-peptide displays a high affinity toward iron(III) ions, producing multi-charged molecular ions and peptide aggregates. Finally, the circular dichroism spectra indicate an unexpected modification of Aβ1–40 peptide conformation upon iron binding.