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Updated: May 29, 2026
07:26
Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides
Published on: November 21, 2013
Length-dependent aggregation of uninterrupted polyalanine peptides
Joseph P Bernacki1, Regina M Murphy
1Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States.
Biochemistry
|September 22, 2011
Summary
Polyalanine (polyA) peptides show length-dependent aggregation, forming stable oligomers above 19 alanines. Longer polyA sequences transition from disordered states to ordered structures, impacting disease mechanisms.
Area of Science:
- Biochemistry
- Molecular Biology
- Biophysics
Background:
- Polyalanine (polyA) is a common homopeptide repeat in eukaryotes.
- Expanded polyA repeats are implicated in human diseases, likely via aggregation.
- Experimental data on uninterrupted polyA conformation and aggregation is limited.
Purpose of the Study:
- To synthesize and characterize uninterrupted polyA peptides (A7-A25).
- To investigate the length-dependent conformation and aggregation properties of polyA.
- To compare polyA behavior with polyglutamine peptides.
Main Methods:
- Synthesis of polyA peptides (A7-A25).
- Characterization of conformation and aggregation using biophysical techniques.
- Analysis of length-dependent solvent properties and assembly.
Main Results:
- PolyA peptides are mostly disordered, with increasing alpha-helix content correlating with length.
- Physiological buffers act as neutral solvents for shorter polyA and poor solvents for longer ones.
- A sharp transition in oligomerization occurs between A19 and A25, with A25 forming stable, small oligomers.
Conclusions:
- PolyA conformation and aggregation are strongly length-dependent.
- The side chain plays a crucial role in regulating polyA conformation and aggregation.
- Understanding polyA aggregation is vital for studying related human diseases.
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