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The nucleation of monomeric parallel beta-sheet-like structures and their self-assembly in aqueous solution
P Chitnumsub1, W R Fiori, H A Lashuel
1Department of Chemistry and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Bioorganic & Medicinal Chemistry
|April 13, 1999
Summary
A novel aromatic diacid residue (1) was designed to induce parallel beta-sheet structures in peptides. Hydrophobic clustering is essential for this folding, leading to self-assembly or monomeric structures.
Area of Science:
- Peptide chemistry
- Supramolecular chemistry
- Biophysical chemistry
Background:
- Designing peptides with specific secondary structures is crucial for understanding protein folding.
- Aromatic diacid residue 4,6-dibenzofuranbispropionic acid (1) was developed to nucleate parallel beta-sheet formation.
- Hydrophobic clustering is hypothesized to play a key role in stabilizing these structures.
Purpose of the Study:
- To investigate the role of hydrophobic clustering in nucleating parallel beta-sheet structures in peptides using residue 1.
- To explore the relationship between intramolecular folding and self-assembly of these peptide structures.
- To develop methods for unlinking folding and assembly for controlled structure formation.
Main Methods:
- Synthesis of peptides incorporating the aromatic diacid residue 1.
- Utilizing spectroscopic and biophysical methods to ascertain peptide structure in aqueous solution.
- Employing a new solid-phase approach for synthesizing N-methylated peptides to control folding and assembly.
Main Results:
- Residue 1 alone, without hydrophobic clustering, was insufficient to nucleate parallel beta-sheet formation.
- A --hydrophobic residue-1-hydrophobic residue-- sequence was found to be necessary for folding into two-stranded parallel beta-sheet structures.
- Most evaluated structures underwent linked folding and self-assembly into fibrillar quaternary structures.
- Asymmetric structures with N-methylated residues were synthesized to unlink folding and assembly.
- Residue 1 facilitated the formation of monomeric parallel beta-sheet-like structures in several peptides.
Conclusions:
- Hydrophobic clustering is a critical factor for initiating parallel beta-sheet folding mediated by residue 1.
- Peptide folding and self-assembly can be linked or unlinked through strategic design, including N-methylation.
- The study provides insights into the formation of parallel beta-sheet structures and their potential for self-assembly.