Design of Peptide-Based Supermolecules Using Self-Assembling β-Sheet Peptides

New-type branched beta-sheet peptides were designed using hydrophilic and hydrophobic amino acids. In the research, (Arg-Ala-Arg-Ala-Asp-Ala-Asp-Ala)(2) (RAD16) and RAD8 peptides were selected as typical sequences having high propensities for forming beta-strands. Thus, Lys residue was selected as a branching point, which introduced the spacer such as (D)Pro-Pro and Gly-Gly-Gly sequences. We investigated the stability of these peptides at several pH values and temperatures by measuring CD spectra and we studied the effects of self-assembling by observation of AFM. RAD16 and branched RAD8/8/16G took beta-sheet structures in water. However, RAD16, branched RAD8/8/16G and branched RAD16/16/8G built up nano fiber formations. Other random coil peptides in water were aggregated according to AFM observations. RAD16 and RAD8 peptides interact with each other and become more structured upon fiber formation.