Phosphatidylethanolamine (PE) is a zwitterionic phospholipid featuring a positively charged ethanolamine phosphoesterified to a negatively charged phosphate group. The acyl chains of PE lipids in Gram-positive membranes are typically 16-18 carbon atoms in length, which may be fully saturated, (usually mono-) unsaturated, or cyclopropanated . Cyclopropanation, which increases under stress or stationary growth phases at the expense of unsaturated acyl chains [241], enhances membrane rigidity, thus reducing the permeability to AMPs and small-molecule antibiotics. The function of PE lipids in the membrane and in its interaction with AMPs is also related to its ability to accumulate in high-curvature regions. The high negative curvature tendency of PE is due to its inverted conical shape, favoring its localization in the septal and polar regions of the cell, with a distribution partially similar to that of cardiolipins .