Reference : Effects of surfactin on membrane models displaying lipid phase separation.
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/136154
Effects of surfactin on membrane models displaying lipid phase separation.
English
Deleu, Magali mailto [Université de Liège - ULiège > Chimie et bio-industries > Chimie biologique industrielle >]
Lorent, Joseph [> >]
Lins, Laurence mailto [Université de Liège - ULiège > Chimie et bio-industries > Biophysique moléc. numér. >]
Brasseur, Robert mailto [Université de Liège - ULiège > Chimie et bio-industries > Biophysique moléc. numér. >]
Braun, Nathalie [> >]
El Kirat, Karim [> >]
Nylander, Tommy [> >]
Dufrene, Yves F. [> >]
Mingeot-Leclercq, Marie-Paule [> >]
2013
Biochimica et Biophysica Acta
1828
2
801-815
Yes (verified by ORBi)
International
0006-3002
[en] Surfactin ; membrane interaction ; phase coexistence ; Laurdan and DPH fluorescence ; Ellipsometry ; AFM
[en] Surfactin, a bacterial amphiphilic lipopeptide is attracting more and more attention in view of its bioactive properties which are in relation with its ability to interact with lipids of biological membranes. In this work, we investigated the effect of surfactin on membrane structure using model of membranes, vesicles as well as supported bilayers, presenting coexistence of fluid-disordered (DOPC) and gel (DPPC) phases. A range of complementary methods was used including AFM, ellipsometry, dynamic light scattering, fluorescence measurements of Laurdan, DPH, calcein release, and octadecylrhodamine B dequenching. Our findings demonstrated that surfactin concentration is critical for its effect on the membrane. The results suggest that the presence of rigid domains can play an essential role in the first step of surfactin insertion and that surfactin interacts both with the membrane polar heads and the acyl chain region. A mechanism for the surfactin lipid membrane interaction, consisting of three sequential structural and morphological changes, is proposed. At concentrations below the CMC, surfactin inserted at the boundary between gel and fluid lipid domains, inhibited phase separation and stiffened the bilayer without global morphological change of liposomes. At concentrations close to CMC, surfactin solubilized the fluid phospholipid phase and increased order in the remainder of the lipid bilayer. At higher surfactin concentrations, both the fluid and the rigid bilayer structures were dissolved into mixed micelles and other structures presenting a wide size distribution.
http://hdl.handle.net/2268/136154
10.1016/j.bbamem.2012.11.007
Copyright (c) 2012 Elsevier B.V. All rights reserved.

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