Published June 17, 2025 13:03
We investigated the formation of amyloids in a known seven amino acid peptide (GNNQQNY). We modified the sequence slightly by replacing the amide group of the side chain involved in forming the resulting nano-sized structure with a group that is unable to form hydrogen bonds. This was achieved by replacing two glutamines (Q) with norleucine (Nle) one by one in two new syntheses. Although the two amino acids (Q and Nle) have the same chain length, they have very different chemical properties. The results showed that new twisted, filamentous nano-sized structures were obtained. Additionally, depending on which glutamine (Q) was replaced, a different twist direction (polymorphism) was observed. These structures could be 'photographed' using atomic force microscopy (AFM), as well as optical spectroscopy methods (ECD, VCD).
These results may be of interest from a materials science point of view, for example in the development of amyloid catalysts, as we were able to produce nanoscale 3D structures reproducibly.