Cell selectivity and antimicrobial mechanism of novel BMAP-28 analogues against bacteria and Cronobacter sakazakii

Antimicrobial peptides (AMPs) have been regarded as promising alternatives to antibiotics but limited by low cell selectivity and high production costs. Sequence truncation is an effective method for activity improvement. Through N-/C-terminal truncation and removal of C-terminal sequences, analogues of bovine myeloid antimicrobial peptide (BMAP-28), a 28-amino-acid peptide, were obtained to develop short peptides with enhanced cell selectivity.

The results indicated that broad-spectrum antibacterial activity was observed in LR-24 and SI-20, particularly against Cronobacter sakazakii. Compared to the template peptide, the therapeutic index of LR-24 and SI-20 increased by four times and 34 times, respectively. The truncated peptides with a β-turn motif and hydrophobic C-terminal residues retained antimicrobial activity. Besides, both cell selectivity and condition sensitivity of LR-24 and SI-20 were improved. At 1 × minimum inhibitory concentration (MIC), LR-24 and SI-20 inhibited 50% of C. sakazakii biofilm formation. Mechanistic studies indicated that AMPs exerted bactericidal activity through membrane disruption.

The results of the present study indicate that the efficacy of LR-24 and SI-20 as therapeutic agents for targeting foodborne pathogens. Moreover, the N-/C-terminal truncation is an effective strategy for developing novel antimicrobials. © 2026 Society of Chemical Industry.