A potent antimicrobial glycolipopeptide GLIP and its promising combined antimicrobial effect

Here, the glycolipopeptide GLIP was obtained by coupling IL-C8 and the monosaccharide molecule D(+)-glucosamine to the N-terminal and C-terminal of the peptide P, which was designed on the basis of the biological characteristics of the antimicrobial peptides. In vitro bioactivity and physicochemical properties assays confirmed that GLIP had excellent antimicrobial activity against Gram-negative E. coli ATCC 25922 and Grampositive S. aureus ATCC 29213, as well as good stability in serum and trypsin, low hemolysis, and good bacterial membrane-disrupting ability. In addition, the glycolipopeptide GLIP could self-assembly in aqueous solution to form spherical nano-aggregates, which could encapsulate the small molecule antibiotic TC to form the nano- medicine GLIP@TC and release the TC continuously and slowly in a sustained-release manner, exerting the combined antimicrobial effect of both. The results of animal experiments demonstrated the excellent in vivo antimicrobial activities of GLIP and nanomedicine GLIP@TC. Finally, molecular docking experiment showed that the GLIP could effectively bind to penicillin-binding protein 5 (PBP5) of E. coli and possibly inhibit its D-Ala carboxypeptidase (CPase) activity. All these results may imply the great potential of GLIP for clinical application against bacterial drug resistance.