Aminoacylated phosphatidylglycerols (PG) are common lipids in the cytoplasmic membranes of Gram-positive bacteria. Their presence in staphylococcal membranes has been linked to increased resistance to a number of antibacterial agents, including antimicrobial peptides. Most commonly, the PG headgroup is esterified to lysine, which converts anionic PG into a cationic lipid with a considerably increased headgroup size. We have been studying how the presence of aminoacylated lipids in lipid vesicles affects the activity of two antimicrobial peptides, cecropin A and mastoparan X. To differentiate between the effects of headgroup charge and size on peptide-lipid interactions, we synthesized two different derivatives. In one, the headgroup was modified by the addition of lysine, and in the other, by glutamine. We find that the aminoacylated lipids can drastically inhibit the release of content from lipid vesicles to a degree that depends on the mode-of-action of the peptide studied.

Aminoacylated phospholipids and their impact on the interactions of antimicrobial peptides with phospholipid vesicles

245th National Meeting (2013)

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