Effects of gramicidin-A on the adsorption of phospholipids to the air-water interface
Effects of gramicidin-A on the adsorption of phospholipids to the air-water interface
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DOI：
10.1016/j.bbamem.2005.09.006
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发表时间：
2005-11-10
影响因子：
3.4
通讯作者：
Hall, SB
中科院分区：
文献类型：
--
作者：
Biswas, SC;Rananavare, SB;Hall, SB
先前的研究表明，疏水表面活性剂蛋白，SP-B和SP-C，促进吸附的脂质在肺表面活性物质的一个水界面，通过稳定的负弯曲的限速结构，是双层囊泡和表面膜之间的中间。空气模型预测，能够稳定负曲率的其他肽也应该促进脂质吸附。以往的报道表明，在适当的条件下，短杆菌肽-A（GrA）诱导二油酰磷脂酰胆碱（DOPC），而不是二肉豆蔻酰磷脂酰胆碱（DMPC），形成负弯曲的六边形-II（H-II）相。本文报道的研究确定了GrA是否会对DMPC和DOPC的吸附产生与疏水表面活性剂蛋白对表面活性剂脂质的吸附相同的影响。小角X射线散射和P-31-核磁共振证实，在用于研究吸附的特定条件下，GrA诱导DOPC形成H-II相，但DMPC保持层状。表面张力的测量结果表明，囊泡中的GrA产生的吸附速率为两个磷脂的一般增加。然而，当限制到界面，在预先存在的膜，GrA与DOPC，但不与DMPC，复制的能力的表面活性剂蛋白质，以促进吸附的囊泡只含有脂质。GrA与两种磷脂的结构和功能效应之间的相关性，以及对GrA与DOPC和疏水表面活性剂蛋白与表面活性剂脂质的吸附的类似效应符合SP-B和SP-C通过稳定具有负曲率的限速中间体来促进吸附的模型。(c)2005 Elsevier B. V.保留所有权利。
Prior studies suggest that the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of the lipids in pulmonary surfactant to an-water interface by stabilizing a negatively curved rate-limiting structure that is intermediate between bilayer vesicles and the surface film. This, air model predicts that other peptides capable of stabilizing negative curvature should also promote lipid adsorption. Previous reports have shown that under appropriate conditions, gramicidin-A (GrA) induces dioleoyl phosphatidylcholine (DOPC), but not dimyristoyl phosphatidylcholine (DMPC), to form the negatively curved hexagonal-II (H-II) phase. The Studies reported here determined if GrA would produce the same effects on adsorption of DMPC and DOPC that the hydrophobic surfactant proteins have on the surfactant lipids. Small angle X-ray scattering and P-31- nuclear magnetic resonance confirmed that at the particular conditions used to study adsorption, GrA induced DOPC to form the H-II phase, but DMPC remained lamellar. Measurements of surface tension showed that GrA in vesicles produced a general increase in the rate of adsorption for both phospholipids. When restricted to the interface, however, in preexisting films, GrA with DOPC, but not with DMPC, replicated the ability of the surfactant proteins to promote adsorption of vesicles containing only the lipids. The correlation between the structural and functional effects of GrA with the two phospholipids, and the similar effects on adsorption of GrA with DOPC and the hydrophobic surfactant proteins with the surfactant lipids fit with the model in which SP-B and SP-C facilitate adsorption by stabilizing a rate-limiting intermediate with negative curvature. (c) 2005 Elsevier B.V. All rights reserved.