Short peptides conjugated to non-peptidic motifs exhibit antibacterial activity

Abstract

Short peptides derived from buforin and lactoferricin B were conjugated with other antimicrobial molecules of different chemical natures. The sequences RLLR, RLLRLLR, RWQWRWQWR, and RRWQWR were conjugated at their N-terminal end with non-peptidic molecules such as 6-aminohexanoic acid, ferrocene, caffeic acid, ferulic acid, and oxolinic acid. Peptide conjugates and unmodified peptides were synthesized by means of solid-phase peptide synthesis using the Fmoc/<i>t</i>Bu strategy (SPPS-Fmoc/<i>t</i>Bu), purified <i>via</i> RP-SPE, and characterized <i>via</i> RP-HPLC and MS. The peptides' antibacterial activity against bacterial strains <i>E. coli</i> ATCC 25922 and <i>S. aureus</i> ATCC 25923 was evaluated, and the results showed that the peptide conjugates exhibited higher antibacterial activity than the original unconjugated peptides. Conjugation of AMPs is a promising strategy for designing and identifying new drugs for treating bacterial infections.