Antimicrobial peptide mimetics based on a diphenylacetylene scaffold: synthesis, conformational analysis and activity

Mimics of natural antimicrobial peptides are promising compounds to fight the rising threat of multi-drug resistant bacteria. Here we report the design, synthesis and conformational analysis of a new class of antimicrobial peptide mimetics incorporating a diphenylacetylene scaffold. Within a small set of compounds, we observe a correlation between amphiphilicity, the efficiency of partitioning into negatively charged membranes and antibacterial activity. The most amphiphilic compound (1) displays species-selective antibacterial activity (most active against Bacillus subtills) and low haemolytic activity. Solution-phase conformational analysis of 1 indicates that a defined structure is adopted in the presence of negatively charged phospholipid membranes and aqueous 2,2,2-trifluoroethanol but not in water. A conformation model indicates that the cationic and hydrophobic functional groups are segregated. These results may inform the development of highly selective antimicrobial peptide mimetics for therapeutic applications.