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Interactions of Buforin II with Phosphatidylcholine and Phosphatidylglycerol Lipid Bilyaers
Author(s) -
Nelson Rachel Beth,
Elmore Donald E.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a519-c
Subject(s) - phosphatidylglycerol , membrane , phosphatidylcholine , förster resonance energy transfer , vesicle , chemistry , biophysics , lipid bilayer , biochemistry , phospholipid , fluorescence , biology , physics , quantum mechanics
The peptide Buforin II (BF2) displays lethal activity toward a wide range of pathogens. Many antimicrobial peptides kill cells by disrupting membranes or forming membrane pores. In contrast, BF2 kills target cells without apparent membrane disruption. The hypothesis is that BF2 diffuses across cell membranes and binds to DNA. To understand BF2’s antimicrobial action, its membrane translocation mechanism must be elucidated. We are investigating the effects of lipid composition on BF2’s translocation using vesicle assays and molecular dynamics (MD) simulations. BF2’s ability to translocate across neutral phosphatidylcholine (PC) or negative phosphatidylglycerol (PG) membranes has been probed with an assay in which fluorescence resonance energy transfer (FRET) is used to visualize the movement of BF2 into vesicles encapsulating trypsin. A similar assay omitting trypsin is used to measure binding of BF2 to PC and PG vesicles. We have run MD simulations of BF2 with PC and PG membranes to obtain molecular‐level insight into these interactions. The data show that BF2 crosses pure PG bilayers, but not PC bilayers. However, the binding curves for PG and PC are similar, indicating that BF2 binds comparably to both surfaces. Therefore, although BF2 is similarly attracted to PC and PG membranes, the negative charge of PG membranes is crucial for translocation.