Theoretical study on symmetric and asymmetric stacking in the self-assembly of bola-amphiphilic peptides into membranes with mixtures of EF4E and KF4K

Abstract

In this work, we conducted a study on peptide membranes formed by the amino acid sequences EF4E and KF4K with the aim of obtaining energetic and structural results for asymmetric and symmetric membrane nanostructures. The results show that the lifetime of hydrogen bonds (HBs) for peptides in the symmetric membrane is ∼12 % higher than that observed for the asymmetric structure, providing greater rigidity to the former. These findings are consistent with those obtained for Coulomb and van der Waals interaction energies and demonstrate that the Symmetric model exhibits better stability compared to the Asymmetric model. The average thickness of the membranes is ∼1.72 ± 0.06 nm and ∼2.27 ± 0.02 nm for the asymmetric and symmetric models, respectively. Our results show that the symmetric model stands out due to greater structural organization and consequently a less hydrated appearance in the membrane region, which could be crucial for applications. From an electrical perspective, both membranes display clear differences, underscoring the influence of peptide arrangement on the membrane structure.