Effects of an amphipathic α-helical peptide on lateral pressure and water penetration in phosphatidylcholine and monoolein mixed membranes
Effects of an amphipathic α-helical peptide on lateral pressure and water penetration in phosphatidylcholine and monoolein mixed membranes
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DOI：
10.1021/jp064988g
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发表时间：
2006-12-14
影响因子：
3.3
通讯作者：
Handa, Tetsurou
中科院分区：
文献类型：
--
作者：
Kamo, Tomoari;Nakano, Minoru;Handa, Tetsurou
通过荧光测量和P-31核磁共振研究了1-棕榈酰基-2-油酰基磷脂酰胆碱(POPC)与非片层形成脂类1-单油酯(MO)的混合膜的物理化学性质以及两亲性α-螺旋肽18A(DWLKAFYDKVAEKLKEAF)对膜的影响。分子内二茂铁基磷脂酰胆碱的形成表明，在分子摩尔分数为0.7时，分子轨道在双层中心附近增加的侧向压力被层状-立方相转变所降低，而即使在相变过程中，极-非极界面附近的侧向压力也是增加的。2-(9-甲氧基)硬脂酸的荧光寿命表明，随着MO含量的增加，水对界面区域的渗透率增加。18A肽的插入降低了界面附近的侧向压力和水的渗透率，并使层状-立方相变向较高的MO组分移动。这表明18A产生了正的曲率应变，降低了侧向压力和水的渗透率。此外，POPC/MO LUV中MO组分的增加促进了18A向膜的分配。这种与含MO膜的优先结合可能归因于18A降低膜应变的倾向。
The physicochemical properties of mixed membranes of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) and a nonlamellar-forming lipid, 1-monoolein (MO), and the effects of an amphipathic alpha-helical peptide, 18A (DWLKAFYDKVAEKLKEAF), on the membranes were investigated by fluorescence measurements and P-31 NMR. The intramolecular excimer formation of dipyrenylphosphatidylcholines showed that the increased lateral pressure near the bilayer center by MO is reduced by the lamellar-cubic phase transition at an MO mole fraction of 0.7, while the lateral pressure near the polar-apolar interface increases even through the phase transition. The fluorescence lifetime of 2-(9-anthroyloxy) stearic acid revealed that water penetration into the interface region increases with the MO fraction. The insertion of the 18A peptide into the membrane interface region decreased both the lateral pressure near the interface and water penetration, and shifted the lamellar-cubic phase transition to a higher MO fraction. This suggests that 18A induces a positive curvature strain and lowers the lateral pressure and water penetration. Furthermore, the increase in the MO fraction in POPC/MO LUV promoted partitioning of 18A to the membranes. This preferential binding to the MO-containing membranes is presumably ascribed to the propensity of 18A to reduce the membrane strain.