Molecular interactions between magainin 2 and model membranes in situ

Nguyen, Khoi Tan, Le Clair, Stephanie V., Ye, Shuji and Chen Zhan (2009) Molecular interactions between magainin 2 and model membranes in situ. Journal of Physical Chemistry B, 113 36: 12358-12363. doi:10.1021/jp904154w

Author Nguyen, Khoi Tan
Le Clair, Stephanie V.
Ye, Shuji
Chen Zhan
Title Molecular interactions between magainin 2 and model membranes in situ
Journal name Journal of Physical Chemistry B   Check publisher's open access policy
ISSN 1520-6106
Publication date 2009-09-10
Year available 2010
Sub-type Article (original research)
DOI 10.1021/jp904154w
Open Access Status
Volume 113
Issue 36
Start page 12358
End page 12363
Total pages 6
Place of publication Washington, DC United States
Publisher American Chemical Society
Collection year 2011
Language eng
Subject 1606 Political Science
2505 Materials Chemistry
2508 Surfaces, Coatings and Films
Abstract In this paper, we investigated the molecular interactions of magainin 2 with model cell membranes using sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Symmetric 1-palmitoyl-2-oleoyl-sn-glycero-3-[Phospho- rac-(1-glycerol)] (POPG) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers, which model the bacterial and mammalian cell membranes, respectively, were used in the studies. It was observed by SFG that magainin 2 orients relatively parallel to the POPG lipid bilayer surface at low solution concentrations, around 200 nM. When increasing the magainin 2 concentration to 800 nM, both SFG and ATR-FTIR results indicate that magainin 2 molecules insert into the POPG bilayer and adopt a transmembrane orientation with an angle of about 20° from the POPG bilayer normal. For the POPC bilayer, even at a much higher peptide concentration of 2.0 μM, no ATR-FTIR signal was detected. For this concentration on POPC, SFG studies indicated that magainin 2 molecules adopt an orientation nearly parallel to the bilayer surface, with an orientation angle of about 75° from the surface normal. This shows that SFG has a much better detection limit than ATR-FTIR and can therefore be applied to study interfacial molecules with a much lower surface coverage. This magainin 2 orientation study and further investigation of the lipid bilayer SFG signals support the proposed toroidal pore model for the antimicrobial activity of magainin 2.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemical Engineering Publications
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