Influence of hydrophobicity on the antimicrobial activity of helical antimicrobial peptides: a study focusing on three mastoparans.

Hydrophobicity is crucial for the interaction between amphipathic antimicrobial peptides and microbial pathogens. However, it is difficult to fully understand the impact of this factor because the biological functions are also influenced by other structural properties, including peptide length, net charge, hydrophilicity, secondary structure, and hydrophobic moment. This study compares three natural antimicrobial peptides-mastoparan C, mastoparan-AF, and mastoparan L-where hydrophobicity varies but other structural features remain nearly identical. Mastoparan C, the most hydrophobic peptide, displays the highest helical content and hemolytic activity, whereas mastoparan-AF, with slightly lower hydrophobicity, demonstrates superior selectivity. In contrast, mastoparan L, the least hydrophobic peptide, exhibits the weakest antimicrobial potency and lowest hemolytic activity, despite showing the least self-assembly. Overall, this study suggests that optimal hydrophobicity, rather than the highest value, enhances antimicrobial efficacy while minimizing hemolytic activity.