Study on the self-assembly of aromatic antimicrobial peptides based on different PAF26 peptide sequences

Antimicrobial peptide (AMP) self-assembly is an effective way to synthesis antimicrobial biomaterials. In previous studies, we found PAF26 AMP (Ac-RKKWFW-NH2) and its derivative K-2-F-2 peptide (Ac-KKRKKWFWFF-NH2) could both self-assemble into hydrogels, but they had distinct microscopic structures. Therefore, in this work five PAF26 peptide derivatives with different numbers of aromatic amino acids are designed to better understand the self-assembly mechanism of aromatic AMP. The transmission electron microscopy, infrared spectroscopy, circular dichroism, and fluorescence spectroscopy characterizations are carried out to study the microscope structure, secondary conformation, and molecular interactions. It is found that the five peptide derivatives have different microscopic structures, and the number of aromatic amino acids will affect the peptide hydrogen bonding and aromatic stacking interactions, causing significant differences in the secondary conformation and microscopic structure. This work will enhance the comprehension of aromatic AMP self-assembly.