PUB - Publikationen an der Universität Bielefeld

In the brains of Alzheimer's disease patients, fibrillar aggregates containing amyloid-beta (Abeta) peptides are found, along with elevated concentrations of Cu(II) ions. The aggregation pathways of Abeta peptides can be modulated by Cu(II) ions and determined by the formation and nature of the Cu(II)-Abeta complex. If spin-labeled, the Cu(II)-Abeta complex contains two dipolar coupled paramagnetic centers, the spin label and the Cu(II) ion. Measurement of the dipolar coupling between these paramagnetic centers by relaxation-induced dipolar modulation enhancement (RIDME) allows to monitor the complex formation and thus opens a way to follow the Cu(II) transfer between peptides if a mixture of wild-type and spin-labeled ones is used. We evaluate this approach for a specific Cu(II)-Abeta complex, the aggregation-inert Component II. The kinetics of the Cu(II) transfer can be resolved by performing RIDME in a time-dependent manner. A temporal resolution of seconds has been achieved, with the potential to reach milliseconds, using a rapid-freeze quench device to stop the Cu(II) transfer in solution after defined incubation times. © 2024 Wiley-VCH GmbH.