Bouffioux O, Berquand A, Eeman M, Paquot M, Dufrêne Y F, Brasseur R, Deleu M
Centre de Biophysique Moléculaire Numérique, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés, 2, B-5030 Gembloux, Belgium.
Biochim Biophys Acta. 2007 Jul;1768(7):1758-68. doi: 10.1016/j.bbamem.2007.04.015. Epub 2007 Apr 29.
Mixed monolayers of the surface-active lipopeptide surfactin-C(15) and various lipids differing by their chain length (DMPC, DPPC, DSPC) and polar headgroup (DPPC, DPPE, DPPS) were investigated by atomic force microscopy (AFM) in combination with molecular modeling (Hypermatrix procedure) and surface pressure-area isotherms. In the presence of surfactin, AFM topographic images showed phase separation for each surfactin-phospholipid system except for surfactin-DMPC, which was in good agreement with compression isotherms. On the basis of domain shape and line tension theory, we conclude that the miscibility between surfactin and phospholipids is higher for shorter chain lengths (DMPC>DPPC>DSPC) and that the polar headgroup of phospholipids influences the miscibility of surfactin in the order DPPC>DPPE>DPPS. Molecular modeling data show that mixing surfactin and DPPC has a destabilizing effect on DPPC monolayer while it has a stabilizing effect towards DPPE and DPPS molecular interactions. Our results provide valuable information on the activity mechanism of surfactin and may be useful for the design of surfactin delivery systems.
通过原子力显微镜（AFM）结合分子建模（超矩阵程序）和表面压力-面积等温线，研究了表面活性脂肽表面活性素-C(15)与各种链长不同（二肉豆蔻酰磷脂酰胆碱、二棕榈酰磷脂酰胆碱、二硬脂酰磷脂酰胆碱）和极性头基不同（二棕榈酰磷脂酰胆碱、二棕榈酰磷脂酰乙醇胺、二棕榈酰磷脂酰丝氨酸）的脂质形成的混合单层。在存在表面活性素的情况下，AFM形貌图像显示，除了表面活性素-二肉豆蔻酰磷脂酰胆碱体系外（该体系与压缩等温线吻合良好），每个表面活性素-磷脂体系均发生相分离。基于畴形状和线张力理论，我们得出结论，表面活性素与磷脂之间的混溶性对于较短链长（二肉豆蔻酰磷脂酰胆碱>二棕榈酰磷脂酰胆碱>二硬脂酰磷脂酰胆碱）更高，并且磷脂的极性头基对表面活性素混溶性的影响顺序为二棕榈酰磷脂酰胆碱>二棕榈酰磷脂酰乙醇胺>二棕榈酰磷脂酰丝氨酸。分子建模数据表明，混合表面活性素和二棕榈酰磷脂酰胆碱对二棕榈酰磷脂酰胆碱单层有去稳定作用，而对二棕榈酰磷脂酰乙醇胺和二棕榈酰磷脂酰丝氨酸分子相互作用有稳定作用。我们的结果为表面活性素的活性机制提供了有价值的信息，可能有助于表面活性素递送系统的设计。
