Issue 7, 2010

Copper(i) and copper(ii) binding to β-amyloid 16 (Aβ16) studied by electrospray ionization mass spectrometry

Abstract

Copper-β-amyloid 16 (Aβ16) complexes were investigated by electrospray ionization mass spectrometry (ESI-MS). Copper(I) and (II) complexes were formed on-line in a microchip electrospray emitter by using a sacrificial copper electrode as the anode in positive ionization mode. In the presence of ascorbic acid in the peptide solution, the amount of Cu(I)-Aβ16 generated electrochemically was even higher. A kinetic model is proposed to account for the generation of copper complexes. The structure of Cu(I)-Aβ16 was investigated by tandem mass spectrometry (MS/MS), and the binding site of Cu(I) to Aβ16 was identified at the His13, His14 residues. Cu(II)-Aβ16 was also investigated by MS/MS and, based on the unusual observations of a-ions, the two binding residues of His13 and His14 of Aβ16 to Cu(II) were also confirmed. This approach provides direct information on Cu(I)-Aβ16 complexes generated in solution from metallic copper and gives evidence that both His13 and His14 are involved in the coordination of both Cu(I)- and Cu(II)-Aβ16 complexes.

Graphical abstract: Copper(i) and copper(ii) binding to β-amyloid 16 (Aβ16) studied by electrospray ionization mass spectrometry

Supplementary files

Article information

Article type
Paper
Submitted
27 Mar 2010
Accepted
12 May 2010
First published
26 May 2010

Metallomics, 2010,2, 474-479

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