Structure modifications have optimized Indolicidin's activity and selectivity. Substituting three proline residues with alanine in the CP-10 derivative enhances ↵-helicity (structure deposited at PDB ID 1hr1) and shifts its action to membrane depolarization and destabilization, without losing its activity against intracellular targets [153] (Figure shows the mechanism of membrane activity). Despite this shift, CP-10 retained its intracellular activity , likely due to enhanced membrane penetration, which increases the intracellular concentrations of the peptide.