Huang C, Li S
Department of Biochemistry, University of Virginia School of Medicine, Charlottesville, VA, USA.
Biochim Biophys Acta. 1999 Nov 16;1422(3):273-307. doi: 10.1016/s0005-2736(99)00099-1.
In this review, we summarize the results of recent studies on the main phase transition behavior of phospholipid bilayers using the combined approaches of molecular mechanics simulations and high-resolution differential scanning calorimetry. Following a brief overview of the phase transition phenomenon exhibited by the lipid bilayer, we begin with the review by showing how several structural parameters underlying various phospholipids including phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol are defined and determined. Specifically, these structural parameters are obtained with saturated lipids packed in the gel-state bilayer using computer-based molecular mechanics calculations. Then we proceed to present the calorimetric data obtained with the lipid bilayer composed of saturated phospholipids as it undergoes the gel-to-liquid-crystalline phase transition in excess water. The general equations that can correlate the gel-to-liquid-crystalline phase transition temperature (T(m)) of the lipid bilayer with the structural parameters of the lipid molecule constituting the lipid bilayer are subsequently presented. From these equations, two tables of predicated T(m) values for well over 400 molecular species of saturated phosphatidylcholine and saturated phosphatidylethanolamine are generated. We further review the structure and chain-melting behavior of a large number of sn-1 saturated/sn-2 unsaturated phospholipids. Two T(m)-diagrams are shown, from which the effects of the number and the position of one to five cis carbon-carbon double bonds on T(m) can be viewed simultaneously. Finally, in the last part of this review, simple molecular models that have been invoked to interpret the characteristic T(m) trends exhibited by lipid bilayers composed of unsaturated lipids with different numbers and positions of cis carbon-carbon double bonds as seen in the T(m)-diagram are presented.
在本综述中，我们总结了利用分子力学模拟和高分辨率差示扫描量热法相结合的方法，对磷脂双层主要相变行为的最新研究成果。在简要概述脂质双层所表现出的相变现象之后，我们首先展示了如何定义和确定包括磷脂酰胆碱、磷脂酰乙醇胺和磷脂酰甘油在内的各种磷脂的几个结构参数。具体而言，这些结构参数是通过基于计算机的分子力学计算，在处于凝胶态双层中的饱和脂质中获得的。然后，我们展示了由饱和磷脂组成的脂质双层在过量水中经历凝胶态到液晶态相变时获得的量热数据。随后给出了可以将脂质双层的凝胶态到液晶态相变温度（T(m)）与构成脂质双层的脂质分子的结构参数相关联的通用方程。根据这些方程，生成了超过400种饱和磷脂酰胆碱和饱和磷脂酰乙醇胺分子种类的预测T(m)值的两个表格。我们进一步综述了大量sn-1饱和/sn-2不饱和磷脂的结构和链熔化行为。展示了两个T(m)图，从中可以同时查看一到五个顺式碳-碳双键的数量和位置对T(m)的影响。最后，在本综述的最后一部分，给出了一些简单的分子模型，这些模型被用来解释如在T(m)图中所见的，由具有不同数量和位置的顺式碳-碳双键的不饱和脂质组成的脂质双层所呈现的特征性T(m)趋势。
