Abstract
Group 3 late embryogenesis abundant (G3LEA) proteins are capable of protecting liposomes from desiccation damage. In our previous studies, a model peptide (PvLEA-22) which has two tandem repeats of the characteristic 11-mer motif found in G3LEA proteins was shown to have a similar protective function for dried liposomes. However, its underlying mechanism is still unclear. It has been hypothesized that PvLEA-22 could prevent direct membrane-membrane contacts by shielding the lipid membrane surface. In this study, to confirm the validity of this hypothesis, we performed molecular dynamics (MD) simulation combined with the so-called umbrella sampling method for a model system composed of PvLEA-22 and a membrane bilayer, and analyzed the free energy profile for the binding process of the peptide onto the membrane surface, and additionally the structure of the bound peptide. As a result, it was shown that the peptide is able to bind to the membrane with a relatively large binding free energy of 18 kcal/mol through a barrierless process, and it has a propensity to form a β-sheet-like structure on the membrane surface due to its characteristic sequence.
