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Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides
Published on: November 21, 2013
Spontaneous fibril formation by polyalanines; discontinuous molecular dynamics simulations
1Department of Chemical Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA.
Journal of the American Chemical Society
|February 9, 2006
Summary
Molecular dynamics simulations reveal how Ac-KA(14)K-NH(2) peptides form beta-sheet fibrils. Peptide concentration and temperature critically influence fibril formation, with hydrophobic interactions favoring amorphous aggregates over fibrils.
Area of Science:
- Biophysics
- Computational Chemistry
- Neuroscience
Background:
- Fibrillary protein aggregates with beta-sheet structures are linked to neurodegenerative diseases.
- Understanding the molecular mechanisms of fibril formation is crucial for disease intervention.
Purpose of the Study:
- To investigate the formation of peptide fibrils using molecular dynamics simulations.
- To explore the influence of peptide concentration, temperature, and interaction strengths on fibril assembly.
Main Methods:
- Discontinuous molecular dynamics simulations were performed on Ac-KA(14)K-NH(2) peptides.
- An off-lattice, implicit-solvent, intermediate-resolution model (PRIME) was utilized.
- Simulations varied peptide concentrations (12-96 peptides) and temperatures.
Main Results:
- Peptide self-assembly into alpha-helices or beta-sheets depends on concentration and temperature.
- Fibril formation occurs at high concentrations above a critical temperature, which decreases with increasing concentration.
- Simulated fibrils exhibit structural characteristics consistent with experimental observations (sheet number, separations, parallel arrangement).
- Stronger hydrophobic interactions relative to hydrogen bonding promote amorphous aggregates instead of fibrils.
Conclusions:
- Peptide concentration and temperature are key determinants of Ac-KA(14)K-NH(2) self-assembly pathways.
- The study provides a molecular-level understanding of fibril formation relevant to neurodegenerative diseases.
- Hydrophobic interactions play a significant role in dictating the morphology of protein aggregates.
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