Competing interactions for antimicrobial selectivity based on charge complementarity

► The selectivity of the antimicrobial peptide NK-2 to procaryotes is studied. ► MD simulations using thermodynamic integration prove stronger binding to procaryotes. ► Electrostatic attraction between peptide and anionic lipids is compensated. ► Release of counterions has major impact on binding affinity. ► Competing interactions are listed.