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Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
Published on: August 28, 2012
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The amyloid precursor protein shows a pH-dependent conformational switch in its E1 domain
Sandra Hoefgen1, Sven O Dahms1, Kathrin Oertwig1
1Protein Crystallography Group, Leibniz Institute for Age Research, Fritz Lipmann Institute (FLI), Beutenbergstrasse 11, 07745 Jena, Germany.
Journal of Molecular Biology
|December 22, 2014
Summary
Alzheimer's disease (AD) research shows that the amyloid precursor protein (APP) changes shape based on pH. This pH-dependent conformational switch in APP-E1 may offer new therapeutic strategies for AD.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Alzheimer's disease (AD) is linked to amyloid precursor protein (APP) and its cleavage product Aβ.
- APP is crucial for neuronal development and homeostasis, functioning at different cellular pH levels.
- APP processing differs based on pH: amyloidogenic in acidic compartments and non-amyloidogenic at neutral/basic pH.
Purpose of the Study:
- To investigate the influence of pH on the APP-E1 domain's structure and function.
- To identify the molecular mechanisms driving pH-dependent conformational changes in APP-E1.
- To explore therapeutic strategies for AD by targeting APP processing.
Main Methods:
- Dynamic light scattering (DLS) to analyze APP-E1 conformation.
- High-resolution X-ray crystallography (1.4 Å) to determine structural details.
- Site-directed mutagenesis and DLS to validate key interactions.
Main Results:
- APP-E1 exhibits pH-dependent interactions between its GFLD and CuBD subdomains.
- APP-E1 adopts a more open conformation at neutral pH and a closed conformation at acidic pH.
- Specific hydrogen bonds (D177-E87, N89-H147) are identified as critical for the pH-driven conformational switch.
Conclusions:
- APP-E1 undergoes significant conformational changes modulated by cellular pH.
- These findings suggest APP's function varies with its cellular localization and associated pH.
- Targeting APP-E1 subdomain interactions presents a novel therapeutic avenue for modulating amyloidogenic processing in AD.
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