Antimicrobial properties of a lipid interactive α-helical peptide VP1 against Staphylococcus aureus bacteria (original) (raw)

Abbreviations < H>, amphiphilicity; DMPE, 1,2-Dimyristoyl-snglycero-3-phosphoethanolamine; DMPG, 1,2-Dimyristoyl-sn-glycero-3-phospho-sn-1-glycerol; FTIR, Fourier transform infra red; , hydrophobicity; HEPES, N-[2-Hydroxyethylpiperazine-N -[2-ethanesulphonic acid]; Tris, Tris{hydroxymethyl} aminomethane. ABSTRACT Theoretical analysis indicates peptide VP1 forms a membrane interactive amphiphilic -helix with antibacterial properties. Fourier transform infra-red based analyses showed VP1 to be -helical (45%) in the presence of vesicle mimics of membranes from S. aureus and to induce increases in the fluidity of these vesicles, as indicated by a rise in wavenumber of circa 0.5 to 1.0 cm -1 . The peptide induced surface pressure increases of 5 mN m -1 in monolayer mimics of S. aureus membranes confirm the formation of an membrane interactive helix. These interactions appeared to involve significant hydrophobic and electrostatic contributions as VP1 induced comparable surface pressure changes in anionic (5.5 mN m -1 ) and zwitterionic (4 mN m -1 ) lipid