Influence of environmental conditions on the interfacial organisation of fengycin, a bioactive lipopeptide produced by Bacillus subtilis
Influence of environmental conditions on the interfacial organisation of fengycin, a bioactive lipopeptide produced by Bacillus subtilis
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DOI：
10.1016/j.jcis.2008.10.017
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发表时间：
2009-01-15
影响因子：
9.9
通讯作者：
Deleu, Magali
中科院分区：
文献类型：
--
作者：
Eeman, Marc;Pegado, Luis;Deleu, Magali
使用表面压力-面积等温线和AFM研究了环境条件对丰原素在空气-水界面上的行为及其与DPPC相互作用的影响。丰霉素的电离状态是其单层界面性质的起源。最有组织的界面安排时，芬枯草菌素的行为，如果有零净电荷（pH 2）。在完全电离状态（pH 7.4）下，芬枯草菌素单层的组织和稳定性取决于亚相中的离子强度。这可以调节芬枯草菌素的表面电位，从而调节界面单层内的静电排斥，以及脂肽与形成空气-水界面的水分子层的相互作用。丰霉素与DPPC的分子间相互作用也受到脂肽的电离状态和单层的表面压力（Pi）的强烈影响。在pH 2下观察到两种界面组分之间的更好的相容性，而带负电荷的脂肽分子与DPPC相分离。在pH 7.4时，当Pi增加时，观察到芬枯草菌素从界面上的渐进解吸，而在pH 2时，当Pi上升到中间平台的Pi值以上时，芬枯草菌素解吸残酷地发生。(C)2008年爱思唯尔公司All rights reserved.
The effect of the environmental conditions both on the behaviour of fengycin at the air-aqueous interface and on its interaction with DPPC was studied using surface pressure-area isotherms and AFM. The ionisation state of fengycin is at the origin of its monolayer interfacial properties. The most organised interfacial arrangement is obtained when fengycin behaves as if having zero net charge (pH 2). In a fully ionised state (pH 7.4), the organisation and the stability of fengycin monolayers depend on the ionic strength in the subphase. This can modulate the surface potential of fengycin and consequently the electrostatic repulsions inside the interfacial monolayer, as well as the lipopeptide interaction with the layer of water molecules forming the air-water interface. Intermolecular interactions of fengycin with DPPC are also strongly affected by the ionisation state of lipopeptide and the surface pressure (Pi) of the monolayer. A better miscibility between both interfacial components is observed at pH 2, while negatively charged lipopeptide molecules are segregated from the DPPC phase. A progressive desorption of fengycin from the interface is observed at pH 7.4 when Pi increases while at pH 2, fengycin desorption brutally occurs when Pi rises above Pi value of the intermediate plateau. (C) 2008 Elsevier Inc. All rights reserved.