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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
Polymorphic structures of Alzheimer's β-amyloid globulomers
1Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio, United States of America.
Plos One
|June 21, 2011
Summary
Computational models reveal Amyloid-β (Aβ) globulomers are stable, off-pathway species distinct from amyloid fibrils. These findings clarify Aβ aggregation kinetics and potential roles in Alzheimer's disease pathogenesis.
Area of Science:
- Biochemistry
- Molecular Biology
- Computational Chemistry
Background:
- Amyloid-β (Aβ) peptide misfolding and aggregation into fibrils are hallmarks of Alzheimer's disease.
- Polymorphic Aβ structures exist, but atomic-level details of their roles in toxicity and formation remain elusive.
- Distinguishing on-pathway from off-pathway aggregates is crucial for understanding disease mechanisms.
Purpose of the Study:
- To model and analyze the molecular structure and dynamics of Aβ globulomers.
- To investigate the structural basis for Aβ globulomer stability and their relationship to amyloid fibril formation.
- To elucidate the biological relevance of Aβ globulomers as potential off-pathway species.
Main Methods:
- Utilized a peptide-packing program and explicit-solvent molecular dynamics (MD) simulations to model Aβ globulomers.
- Performed structural and energetic analyses of the modeled Aβ structures.
- Compared computational findings with experimental data, including AFM and H/D amide exchange NMR.
Main Results:
- Aβ globulomers exhibit stable conformations, preferentially organized by dynamic dimeric subunits with a hydrophobic core.
- Their structure (curved surface, compact size, low β-structure) hinders conversion to amyloid fibrils, indicating off-pathway behavior.
- Modeled globulomer properties align with experimental data on size, subunit organization, and molecular weight.
Conclusions:
- Computationally modeled Aβ globulomers offer insights into their unique structure, dynamics, and polymorphism compared to Aβ fibrils.
- Findings suggest Aβ globulomers are off-pathway species, independent of amyloid fibril aggregation kinetics.
- This work aids in understanding Aβ aggregation pathways and their implications for Alzheimer's disease.
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