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High affinity binding of amyloid β-peptide to calmodulin: Structural and functional implications
Isaac Corbacho1, María Berrocal1, Katalin Török2
1Dept. Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, Avda. de Elvas, s/n, 06006 Badajoz, Spain.
Biochemical and Biophysical Research Communications
|April 2, 2017
Summary
Alzheimer's disease (AD) involves amyloid-beta peptides (Aβ) and calcium. This study reveals Aβ binds tightly to calmodulin (CaM), a calcium-binding protein, potentially slowing Aβ fibrillation and offering new therapeutic avenues.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Amyloid-beta peptides (Aβ) are key in Alzheimer's disease (AD) pathogenesis, linked to neurotoxicity and calcium dysregulation.
- Calmodulin (CaM) is crucial for neuronal calcium signaling and regulates amyloid precursor protein (APP) processing.
Purpose of the Study:
- To investigate the binding interaction between Aβ and CaM.
- To determine the affinity and functional consequences of Aβ-CaM interaction.
Main Methods:
- Utilized fluorescently labeled CaM (Badan-CaM) and Aβ(1-42) (HiLyte™-Fluor555).
- Measured binding affinity using dissociation constants (Kd).
Main Results:
- Aβ binds with high affinity to CaM, primarily through the Aβ25-35 domain.
- Binding affinity is significantly higher (approx. 20-fold) for calcium-saturated CaM compared to apo-CaM.
- A dissociation constant (Kd) of 0.98 ± 0.11 nM indicates CaM is a high-affinity target for Aβ.
- Aβ-CaM interaction was observed to slow down Aβ fibrillation.
Conclusions:
- Calmodulin is a high-affinity cellular target for neurotoxic Aβ peptides.
- The novel Aβ-CaM interaction provides new insights into Aβ neurotoxicity mechanisms.
- Calmodulin and its derived peptides represent potential therapeutic targets for Alzheimer's disease.