| Abstract: | In this work, we employed Raman spectroscopy to study the effect of the antimicrobial peptide lactoferricin B (LfB) on model cell membranes. We used two derivatives of LfB (RRWQWRMKKLG and RRWQWR) with broad‐spectrum activity against gram‐positive and gram‐negative bacteria, fungus, viruses and tumors. Raman spectra of the peptides showed no conformational change in the temperature range 4–60 °C. The positions of the amide I and amide III bands suggest that in an aqueous solution these peptides preferentially adopt a random coil‐like conformation. We also investigated the effect the peptides had on the melting behavior of model cell membranes composed of zwitterionic lipid dipalmitoylglycero‐phosphocholine (DPPC) and anionic lipid dipalmitoylglycero‐phosphoglycerol (DPPG). Raman CH stretching bands were used to follow the melting of the lipid vesicles. We found that the melting of DPPC lipid vesicles is not affected by the presence of the peptides, while the presence of the peptides reduced cooperativity of the phase transition for anionic DPPG vesicle, suggesting that both peptides interact strongly and specifically with this model cell membrane composed of anionic lipid. Copyright © 2006 John Wiley & Sons, Ltd. |
