Amyloid-beta-copper interaction studied by simultaneous nitrogen K and copper L2,3 -edge soft X-ray absorption spectroscopy

Jinghui Luo; Hongzhi Wang; Jinming Wu; Vladyslav Romankov; Niéli Daffé; Jan Dreiser

doi:10.1016/j.isci.2021.103465

Amyloid-beta-copper interaction studied by simultaneous nitrogen K and copper L_2,3 _-edge soft X-ray absorption spectroscopy

iScience. 2021 Nov 16;24(12):103465. doi: 10.1016/j.isci.2021.103465. eCollection 2021 Dec 17.

Authors

Jinghui Luo¹, Hongzhi Wang¹, Jinming Wu¹, Vladyslav Romankov², Niéli Daffé², Jan Dreiser²

Affiliations

¹ Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
² Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.

Abstract

We study the interaction between amyloid β (Aβ) peptides and Cu and Zn metal ions by using soft X-ray absorption spectroscopy. The spectral features of the peptides and Cu are simultaneously characterized by recording spectra at the N K-edge and at the Cu L_2,3 _-edges. In the presence of the peptides, the Cu L_2,3 _-edge shows a fingerprint of monovalent Cu(I), caused by the interaction with the peptides. The appearance of Cu(I) is less significant at an acidic pH than at a basic pH. Furthermore, aggregation leads to a smaller signature of Cu(I). N K-edge spectra reveal that Cu and Zn ions exhibit a different coordination with the nitrogen atoms in the peptides. This suggests different roles of Cu and Zn in the peptide aggregation. Our work provides physical insight into the participation of the metal ions and Aβ in the toxic reactive oxygen species formation.

Keywords: Biochemistry; Biophysical chemistry; Organometallic chemistry; Physical chemistry.