Angewandte Chemie [BCB]

Abstract

The redox activity of Cu ions bound to the amyloid-β (Aβ) peptide is implicated as a source of oxidative stress in the context of Alzheimer's disease. In order to explain the efficient redox cycling between Cu(II)-Aβ (distorted square pyramidal) and Cu(I)-Aβ (digonal) resting states, the existence of a low-populated "in-between" state, prone to bind Cu in both oxidation states, has been postulated. Here, we exploited the partial X-ray induced photoreduction at 10 K, followed by a thermal relaxation at 200 K, to trap and characterize by X-ray Absorption Spectroscopy (XAS) a partially reduced Cu-Aβ1−16 species different from the resting states. Remarkably, the XAS spectrum is well-fitted by a previously proposed model of the "in-between" state, hence providing the first direct spectroscopic characterization of this intermediate state. The present approach could be used to explore and identify the catalytic intermediates of other relevant metal complexes.

 

Reference

Chasing the Elusive "In-Between" State of the Copper-Amyloid-β Complex by X-ray Absorption through Partial Thermal Relaxation after Photoreduction

Enrico Falcone, Germano Nobili, Michael Okafor, Olivier Proux, Giancarlo Rossi, Silvia Morante, Peter Faller, Francesco Stellato

Angewandte Chemie , Publication date March 3 – DOI: 10.1002/anie.202217791

Contact

Peter Faller (team BCB), Institut de Chimie de Strasbourg (UMR 7177).