Temperature dependence of structure, bending rigidity, and bilayer interactions of dioleoylphosphatidylcholine bilayers
Temperature dependence of structure, bending rigidity, and bilayer interactions of dioleoylphosphatidylcholine bilayers
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DOI：
10.1529/biophysj.107.115691
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发表时间：
2008-01-01
影响因子：
3.4
通讯作者：
Nagle, John F.
中科院分区：
文献类型：
--
作者：
Pan, Jianjun;Tristram-Nagle, Stephanie;Nagle, John F.
X-射线漫散射测量从定向堆栈和单层囊泡的二油酰磷脂酰胆碱脂质双层的结构和材料性能的温度依赖性。面积/分子，A，在45摄氏度时为75.5埃（2），在30摄氏度时为72.4埃（2），在15摄氏度时为69.1埃（2），这给出了在30摄氏度时的面积膨胀率α（A）= 0.0029/deg，并且我们表明该值与聚合物刷理论非常一致。随着温度的升高，双层变得更薄;烃部分的收缩率为α（Dc）= 0.0019/deg; aA和aDc之间的差异与先前测量的体积膨胀率α（Vc）= 0.0010/deg一致。随着T（K）的增加，弯曲模量KC以exp（455/T）的形式减小。我们的面积压缩模量K-A随着温度的升高而降低5%，与十二烷/水的表面张力相同，再次与聚合物刷理论一致。关于双层之间的相互作用，压缩模量B作为双层间水间距D '（W）的函数被发现几乎与温度无关。由B和K-C计算的排斥涨落压力随温度而增加，而货车德瓦耳斯相互作用的Hamaker参数几乎与温度无关;这解释了为什么我们从结构结果中得到的完全水合水间距D '（W）随温度而增加。
X-ray diffuse scattering was measured from oriented stacks and unilamellar vesicles of dioleoylphosphatidylcholine lipid bilayers to obtain the temperature dependence of the structure and of the material properties. The area/molecule, A, was 75.5 angstrom(2) at 45 degrees C, 72.4 angstrom(2) at 30 degrees C, and 69.1 angstrom(2) at 15 degrees C, which gives the area expansivity alpha(A) = 0.0029/deg at 30 degrees C, and we show that this value is in excellent agreement with the polymer brush theory. The bilayer becomes thinner with increasing temperature; the contractivity of the hydrocarbon portion was alpha(Dc) = 0.0019/deg; the difference between aA and aDc is consistent with the previously measured volume expansivity alpha(Vc) = 0.0010/deg. The bending modulus KC decreased as exp(455/T) with increasing T (K). Our area compressibility modulus K-A decreased with increasing temperature by 5%, the same as the surface tension of dodecane/water, in agreement again with the polymer brush theory. Regarding interactions between bilayers, the compression modulus B as a function of interbilayer water spacing D'(W) was found to be nearly independent of temperature. The repulsive fluctuation pressure calculated from B and K-C increased with temperature, and the Hamaker parameter for the van der Waals interaction was nearly independent of temperature; this explains why the fully hydrated water spacing, D'(W), that we obtain from our structural results increases with temperature.