Dynamics of 24 Self-Assembling H-(RADA)₄-OH Peptides Complexed in Bi-Layered Structure with Layers in <i>syn</i> and <i>anti</i> Orientation

Abstract

H-(RADA)4-OH peptide in water tends to form biolgels at physiological conditions. Thusly made scaffold is formed of fibrils resulted from peptides self-assembling. Fibrils have two external hydrophilic layers, while hydrophobic one is situated between of them. Bio gels by the H-(RADA)4-OH peptides are considered to be a prominent source for designed extra cellular matrix aimed to cell cultures of different types. Little is known about detailed structure the filament structure and β-sheets peptide composition. We have designed and studied molecular dynamics of bi-layered protofilament structures with β-sheets formed of parallel or anti-parallel peptide chains. Method of molecular dynamics was used to study H-(RADA)4-OH peptide complexes at 80 and 300 K. While the most stable peptide complex was found to consist of anti-parallel peptides, had the lowest free energy and the least deviation of atom coordinates, yet another stable structure of the peptide complex was identified as 24-mer of parallel peptides with two β-sheets placed in syn orientation. These results underlined the importance of factors, directing the initial stages of the H-(RADA)4-OH peptide self-assembling in solution.