Okulski W, Sujak A, Gruszecki W I
Department of Biophysics, Medical Academy, Lublin, Poland.
Biochim Biophys Acta. 2000 Dec 20;1509(1-2):216-28. doi: 10.1016/s0005-2736(00)00298-4.
The model of a dipalmitoylphosphatidylcholine (DPPC) bilayer containing a xanthophyll pigment zeaxanthin (ZEA) is proposed. The model is based on the ten-state Pink-Green-Chapman model of a lipid monolayer. The Monte Carlo method of computer simulation has been applied. Our model of the lipid membrane consists of two lipid monolayers with ZEA molecules spanning the lipid bilayer. The concentration of ZEA molecules is assumed to be conserved. Within the model, the interactions between lipid monolayers in a bilayer exist through ZEA molecules only. The experimental data concerning the aggregation of ZEA in DPPC from the literature and from our research were applied as a criterion to fit the model parameters. The model gives the dependences of the main phase transition temperature on ZEA/DPPC molar ratio, the percentage of ZEA in a monomeric form on ZEA/DPPC molar ratio and on temperature. The dependences obtained within the model and the experimental ones are in qualitative agreement. The influence of intermolecular interaction parameters on ZEA aggregation has been discussed. The differences between the model and the experimental results concerning mainly the pattern of ZEA aggregation have been discussed. Analyses of the lipid microconfiguration allow to advance the hypothesis concerning the influence of ZEA on the membrane permeability.
提出了一种包含叶黄素类色素玉米黄质（ZEA）的二棕榈酰磷脂酰胆碱（DPPC）双层模型。该模型基于脂质单层的十态粉红-绿色-查普曼模型。应用了计算机模拟的蒙特卡罗方法。我们的脂质膜模型由两个脂质单层组成，ZEA分子跨越脂质双层。假设ZEA分子的浓度守恒。在该模型中，双层中脂质单层之间的相互作用仅通过ZEA分子存在。将文献和我们研究中关于ZEA在DPPC中聚集的实验数据用作拟合模型参数的标准。该模型给出了主相变温度对ZEA/DPPC摩尔比的依赖性、单体形式的ZEA百分比对ZEA/DPPC摩尔比和温度的依赖性。模型得出的依赖性与实验结果在定性上一致。讨论了分子间相互作用参数对ZEA聚集的影响。讨论了模型与实验结果之间主要关于ZEA聚集模式的差异。对脂质微构型的分析有助于提出关于ZEA对膜通透性影响的假设。
