Impact of the Arrangement Modes of the Antimicrobial Motifs WWR-7 and its Analogs in CAMPs on Their Therapeutic Properties.

This study investigates the impact of the antimicrobial motif (WWR-7, LRWWRRLNH₂) arrangement, either in tandem or as branches, on the structure-activity of cationic dimeric antimicrobial peptides (CAMPs). WWR-7 was modified in charge (Arg to Leu) and amino acid composition (Leu to Val/ L- to D- amino acids) to generate dimers aimed at improving their activity, selectivity, and stability. Dimerization enhanced the activity of the dimers over that of the monomer, primarily due to electrostatic interactions. While linear dimers boosted the activity through secondary structure formation, branched dimers contributed to high charge density and protease/serum stability. In low-charged dimers, the branched analogs had better activity than linear ones, while in Val dimers, linear dimers fared better. Branching increased the selectivity over linear dimerization. WWR-14dV, 2BWWR-7 V, and 2BWWR-7dV emerged as the lead peptides having high, salt-tolerant, and fast bactericidal efficacy against ESKAPE pathogens, drug-resistant pathogens (MRSA/VRSA), and fungus Candida albicans. Additionally, these peptides exhibited high antibiofilm efficacy against MRSA and Pseudomonas aeruginosa, protease/serum stability, nondevelopment of resistance against pathogens, high selectivity, and ability to be used in combination with ciprofloxacin to mitigate MRSA infections. Thus, linear and branched dimerization are both efficient techniques, having respective strengths and weaknesses that can be exploited to generate potential antimicrobials.