Structure–activity relationships of gramicidin S analogs containing (β-3-pyridyl)-α,β-dehydroalanine residues on membrane permeability

The synthesis, biological activities and membrane permeability of gramicidin S (GS) analogs containing (Z)-(β-3-pyridyl)-α,β-dehydroalanine (ΔZ3Pal) residues are described. The cationic side chains of the Orn and ΔZ3Pal4,4′ residues in [ΔZ3Pal4,4′]GS (1) are important for dissociating antimicrobial and hemolytic activity.