Grau A, Gómez Fernández J C, Peypoux F, Ortiz A
Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, E-30100 Espinardo, Murcia, Spain.
Biochim Biophys Acta. 1999 May 12;1418(2):307-19. doi: 10.1016/s0005-2736(99)00039-5.
Surfactin, an acidic lipopeptide produced by various strains of Bacillus subtilis, behaves as a very powerful biosurfactant and posses several other interesting biological activities. By means of differential scanning calorimetry and X-ray diffraction the effect of surfactin on the phase transition properties of bilayers composed of different phospholipids, including lipids forming hexagonal-HII phases, has been studied. The interactions of surfactin with phosphatidylcholine and phosphatidylglycerol seem to be optimal in the case of myristoyl acyl chains, which have a similar length to the surfactin hydrocarbon tail. Data are shown that support formation of complexes of surfactin with phospholipids. The ionized form of surfactin seems to be more deeply inserted into negatively charged bilayers when Ca2+ is present, also supporting the formation of surfactin-Ca2+ complexes. In mixtures with dielaidoylphosphatidylethanolamine, a hexagonal-HII phase forming lipid, surfactin displays a bilayer stabilizing effect. Our results are compatible with the marked amphiphilic nature of surfactin and may contribute to explain some of its interesting biological actions; for instance the formation of ion-conducting pores in membranes.
表面活性素是由多种枯草芽孢杆菌菌株产生的一种酸性脂肽，它是一种非常强大的生物表面活性剂，还具有其他一些有趣的生物活性。通过差示扫描量热法和X射线衍射，研究了表面活性素对由不同磷脂组成的双层膜（包括形成六方-HII相的脂质）相变特性的影响。在肉豆蔻酰基链的情况下，表面活性素与磷脂酰胆碱和磷脂酰甘油的相互作用似乎最为理想，其长度与表面活性素的烃尾相似。有数据表明支持表面活性素与磷脂形成复合物。当存在Ca2+时，表面活性素的离子化形式似乎更深入地插入带负电荷的双层膜中，这也支持了表面活性素-Ca2+复合物的形成。在与形成六方-HII相的脂质二油酰磷脂酰乙醇胺的混合物中，表面活性素表现出双层稳定作用。我们的结果与表面活性素显著的两亲性质相符，可能有助于解释其一些有趣的生物学作用；例如在膜中形成离子传导孔。
