Effects of a cationic and hydrophobic peptide, KL4, on model lung surfactant lipid monolayers
Effects of a cationic and hydrophobic peptide, KL4, on model lung surfactant lipid monolayers
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DOI：
10.1016/s0006-3495(98)77899-3
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发表时间：
1998-04-01
影响因子：
3.4
通讯作者：
Zografi, G
中科院分区：
文献类型：
--
作者：
Ma, JW;Koppenol, S;Zografi, G
我们报道了疏水性阳离子肽[赖氨酸-（亮氨酸）（4）]（4）-赖氨酸（KL 4）在25 ℃和pH 7.2下在空气/水界面上的表面行为，以及其在非常低的摩尔比下对两性离子磷脂1，2-二棕榈酰磷脂酰胆碱（DPPC）表面性质的影响，以及1-棕榈酰-2-油酰磷脂酰甘油（POPG）和棕榈酸（PA）的阴离子形式，以各种组合。通过用Wilhelmy板技术测量平衡铺展压力（pi（e））和表面压力-面积等温线（pi-A）来评价表面性质。用荧光显微镜观察表面相分离。KL 4本身形成单相单层，在高达30 mN/m的表面压力pi下稳定，并与DPPC形成不混溶的单层混合物。POPG和KL 4在低pi区域中没有检测到强相互作用，而PA/KL 4二元混合物形成稳定的单层，这归因于带相反电荷的PA和KL 4之间的离子相互作用。KL 4对DPPC/POPG混合物具有显著的影响，因为它促进表面相分离，同时还增加pi（e）和pi（max），并且这些影响在PA存在下大大增强。在我们提出的模型中，KL 4有利于分离DPPC富集相和POPG/PA富集相，以实现表面细化。正是这两个相可以实现高表面压力稳定性和有效扩散的重要肺表面活性剂功能。
We report on the surface behavior of a hydrophobic, cationic peptide, [lysine-(leucine)(4)](4)-lysine (KL4), spread at the air/water interface at 25 degrees C and pH 7.2, and its effect at very low molar ratios on the surface properties of the zwitterionic phospholipid 1,2-dipalmitoylphosphatidylcholine (DPPC), and the anionic forms of 1-palmitoyl-2-oleoylphosphatidylglycerol (POPG) and palmitic acid (PA), in various combinations. Surface properties were evaluated by measuring equilibrium spreading pressures (pi(e)) and surface pressure-area isotherms (pi-A) with the Wilhelmy plate technique. Surface phase separation was observed with fluorescence microscopy. KL4 itself forms a single-phase monolayer, stable up to a surface pressure pi of 30 mN/m, and forms an immiscible monolayer mixture with DPPC. No strong interaction was detected between POPG and KL4 in the low pi region, whereas a stable monolayer of the PA/KL4 binary mixture forms, which is attributed to ionic interactions between oppositely charged PA and KL4. KL4 has significant effects on the DPPC/POPG mixture, in that it promotes surface phase separation while also increasing pi(e) and pi(max), and these effects are greatly enhanced in the presence of PA. In the model we have proposed, KL4 facilitates the separation of DPPC-rich and POPG/PA-rich phases to achieve surface refinement. It is these two phases that can fulfill the important lung surfactant functions of high surface pressure stability and efficient spreading.