All-atom MD simulations of the peptides, parent p8C and less cytotoxic 7a, in a watermembrane environments were performed. The model membrane mimicking the mammalian cells was represented by a DOPC lipid bilayer. In addition, MD simulation of peptide 7a was carried out in the presence of a two-component bilayer (DOPC/DOPG with a molar ratio of 75/25%) mimicking a bacterial membrane. The MD data obtained were compared with the results of modeling of p1 in an analogous water-bilayer system, described earlier . Both model membranes contained 128 lipid molecules. Finally, multiple MD production runs were conducted in an NPT ensemble at a semi-isotropic pressure and a constant temperature of 310 K with an integration step of 2 fs.