Joanna Juhaniewicz

Interactions of cationic peptide, melittin, with model lipid membranes

Joanna Juhaniewicz, UW ,
Supervisor: dr. hab. Slawomir Sek (UW)

Antimicrobial peptides (AMPs) are small molecules with broad spectrum of the antimicrobial activity against bacteria, viruses and fungi. These peptides are mainly positively charged and possess both hydrophobic and hydrophilic sides which enable the interactions with lipid membranes. One of the examples is melittin, an amphipathic peptide from the venom of the European bee that exhibits a strong action on phospholipid membranes with pore formation.
In order to gain a deeper insight into the melittin-lipid interactions we examined lipids with different hydrocarbon chains like 1,2-dimistyroyl-sn-glycero-3-phosphoholine (DMPC) and 1,2- dipalmitoyl-sn-glycero-3-phosphoholine (DPPC) and different polar groups like 1,2- dimistyroyl-sn-glycero-3-phosphoglycerol (DMPG). Firstly, the interactions of peptide with lipid membranes were investigated at the air-water interface by preparing the mixed monolayers with different ratio of melittin. Next, layers composed of pure lipids and mixed layers were transferred onto the gold substrate using the Langmuir- Blodgett or Langmuir-4 Schaefer techniques and the melittin-lipid interactions were investigated using electrochemical and spectroscopic methods.

Discussion