Gruen D W
Biochim Biophys Acta. 1980 Jan 25;595(2):161-83. doi: 10.1016/0005-2736(80)90081-4.
A statistical mechanical model of a bilayer of dipalmitoyl-3-sn-phosphatidylcholine molecules above their phase transition is presented. A molecular field approximation developed in previous work by Marcelja is extended by setting the molecular field at each depth in the bilayer in proportion to the average chain order at that depth. The free energy of the hydrocarbon/water interface and that due to the interaction of the polar headgroups is included in the evaluation of the statistical weights of the chain conformations. The model gives good agreement with several independent experimental results. It resolves the dilemma posed by the experimental evidence that there is (i) a considerable variation in order parameter along the lipid chain, but (ii) no collective tilt in the more ordered region of the chain. The model gives an explanation of how the lipid chains pack under these two constraints. The order parameter profile down the chain does not correspond to the profile across the bilayer.
提出了一种处于相变温度以上的二棕榈酰-3- sn -磷脂酰胆碱分子双层的统计力学模型。通过使双层中每个深度处的分子场与该深度处的平均链序成比例，扩展了马塞尔亚先前工作中发展的分子场近似。在评估链构象的统计权重时，纳入了烃/水界面的自由能以及极性头基团相互作用产生的自由能。该模型与几个独立的实验结果吻合良好。它解决了实验证据所带来的困境，即：（i）沿脂质链的序参量存在相当大的变化，但（ii）在链的更有序区域没有集体倾斜。该模型解释了脂质链在这两个约束条件下是如何堆积的。沿链的序参量分布与跨双层的分布并不对应。
