Related Experiment Video
Updated: Jun 20, 2026

Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides
Published on: August 20, 2018
Self-assembly of a modified amyloid peptide fragment: pH-responsiveness and nematic phase formation
Ian W Hamley1, Valeria Castelletto, Claire Moulton
1Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK. i.w.hamley@reading.ac.uk
Abstract:
The self-assembly of peptide YYKLVFFC based on a fragment of the amyloid beta (A beta) peptide, A beta 16-20, KLVFF has been studied in aqueous solution. The peptide is designed with multiple functional residues to examine the interplay between aromatic interactions and charge on the self-assembly, as well as specific transformations such as the pH-induced phenol-phenolate transition of the tyrosine residue. Circular dichroism (CD) and Fourier-transform infrared (FTIR) spectroscopies are used to investigate the conditions for beta-sheet self-assembly and the role of aromatic interactions in the CD spectrum as a function of pH and concentration. The formation of well-defined fibrils at pH 4.7 is confirmed by cryo-TEM (transmission electron microscope) and negative stain TEM. The morphology changes at higher pH, and aggregates of short twisted fibrils are observed at pH 11. Polarized optical microscopy shows birefringence at a low concentration (1 wt.-%) of YYKLVFFC in aqueous solution, and small-angle X-ray scattering was used to probe nematic phase formation in more detail. A pH-induced transition from nematic to isotropic phases is observed on increasing pH that appears to be correlated to a reduction in aggregate anisotropy upon increasing pH.
Related Concept Videos
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Folding
Protein Complex Assembly
Many viruses self-assemble into a fully functional unit using the infected host cell to...
Protein Organization

