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Quantifying the Binding Interactions Between CuII and Peptide Residues in the Presence and Absence of Chromophores
Published on: April 5, 2022
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Aβ5- Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes
Nina E Wezynfeld1, Aleksandra Tobolska1,2, Mariusz Mital3
1Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
Inorganic Chemistry
|September 14, 2020
Summary
Amyloid-beta (Aβ)5- peptides bind copper(II) ions with high affinity, potentially impacting copper handling in Alzheimer's disease. These findings highlight Aβ5- peptides as significant players in copper dyshomeostasis.
Area of Science:
- Biochemistry
- Coordination Chemistry
- Neuroscience
Background:
- Amyloid-beta (Aβ)5- peptides are minor species in normal brains but increase with enzyme inhibitors.
- They possess an Arg-His metal-binding sequence, forming a 3-nitrogen (3N) chelate system capable of binding Cu(II).
Purpose of the Study:
- To investigate Cu(II) complex formation and reactivity of truncated Aβ5- peptide models.
- To understand the role of these peptides in copper handling and potential implications for Alzheimer's disease.
Main Methods:
- Circular Dichroism (CD) spectroscopy
- UV-visible (UV-vis) spectroscopy
- Potentiometry
Main Results:
- All tested peptides (Aβ5-9, Aβ5-12, Aβ5-12Y10F, Aβ5-16) coordinated Cu(II) with high affinities (>3 × 1012 M-1 at pH 7.4).
- Aβ5-16 showed a 3-fold increase in affinity due to internal macrochelation.
- Cu-Aβ5- complexes could be reduced to Cu(I) and oxidized to Cu(III), with imidazole coordination influencing redox stability.
Conclusions:
- Aβ5- peptides bind Cu(II) strongly, more so than Aβ1- peptides.
- These peptides may interfere with copper handling, contributing to copper dyshomeostasis in Alzheimer's disease brains.
