Amphiphilic cyclic peptide [W4KR5]-Antibiotics combinations as broad-spectrum antimicrobial agents

Membrane-Active Cyclic Amphiphilic Peptides: Broad-Spectrum Antibacterial Activity Alone and in Combination with Antibiotics

“…Additionally, R provides the hydrogen bonding geometry necessary for membrane translocation . Moreover, W demonstrates a crucial function in membrane association due to its substantial preference for the interfacial regions of lipid bilayers, leading to the enhancement of the antimicrobial properties of the peptides. ,, …”

“…56 Moreover, W demonstrates a crucial function in membrane association due to its substantial preference for the interfacial regions of lipid bilayers, leading to the enhancement of the antimicrobial properties of the peptides. 51,52,70 The minimum inhibitory concentration (MIC) values for synthesized cyclic peptides were measured using a microbroth dilution assay to determine the antibacterial activity against Gram-positive and Gram-negative strains. Four bacterial strains, including two multidrug-resistant strains (Grampositive methicillin-resistant Staphylococcus aureus (S. aureus BAA-1556, MRSA) and Gram-negative Klebsiella pneumoniae (K. pneumoniae BAA-1705)) and two nonresistant strains (Gram-negative Pseudomonas aeruginosa (P. aeruginosa 27883) and Escherichia coli (E. coli 25922)) were used for antibacterial screening (Table 1).…”

“…64,65 Our group has previously discovered and reported that cyclic peptides [R 4 W 4 ] (Figure 1) and [W 4 KR 5 ] containing W and R residues assembled in an ordered manner to have antibacterial activity against multidrug-resistant pathogens, especially, against Gram-positive bacteria. 50,51 Moreover, [R 4 W 4 ] showed cell-penetrating properties in eukaryotic cells and bactericidal effects in the [R 4 W 4 ]/tetracycline combination against MRSA and E. coli. 50 Cyclic peptides showed higher antibacterial activities compared to the corresponding linear counterparts.…”

Novel self-assembling cyclic peptides with reversible supramolecular nanostructures

“…It is well-known that many naturally-derived cyclic peptides have anticancer, antibacterial, antifungal, and antibiotic properties, exhibiting remarkable in vitro cytotoxicity against numerous types of cells: 68–70 some of them act as potent growth inhibitors, with apoptotic effects against numerous human cancer cell lines. 71 Indeed, compared to linear peptides, cyclic peptides have better biological activity and an increased selectivity toward target molecules, due to the structural rigidity of their conformation. This peculiar characteristic increases their biochemical stability, binding affinity, and cell membrane permeability, making them suitable for therapeutic applications.…”

“…63 Cyclic peptides could overcome this limitation because they were reported to feature lower degradation and high physiological stability. 64 Thus, we investigated the rheological properties of cyclic-FAQ-LDLK12, FAQ-LDLK12 and Ac-FAQ-LDLK12 (Fig. S2, ESI †).…”