Nagle J F
J Membr Biol. 1976;27(3):233-50. doi: 10.1007/BF01869138.
Headgroup and soft core interactions are added to a lipid monolayer-bilayer model and the surface pressure-area phase diagrams are calculated. The results show that quite small headgroup interactions can have biologically significant effects on the transition temperature and the phase diagram. In particular, the difference in transition temperatures of lecithins and phosphatidyl ethanolamines is easy to reproduce in the model. The phosphatidic acid systems seem to require weak transient hydrogen bonding which is also conjectured to play a role in most of the lipid systems. By a simple surface free energy argument it is shown that monolayers under a surface pressure of 50 dynes/cm should behave as bilayers, in agreement with experiment. Although the headgroup interactions are biologically very significant, in fundamental studies of the main phase transition in lipids they are secondary in importance to the hydrocarbon chain interactions (including the excluded volume interaction, the rotational isomerism, and the attractive van der Waals interaction).
将头基和软核相互作用添加到脂质单层-双层模型中，并计算表面压力-面积相图。结果表明，相当小的头基相互作用会对转变温度和相图产生生物学上显著的影响。特别是，卵磷脂和磷脂酰乙醇胺转变温度的差异在该模型中很容易重现。磷脂酸体系似乎需要弱的瞬态氢键，这也被推测在大多数脂质体系中起作用。通过一个简单的表面自由能论证表明，表面压力为50达因/厘米的单层应表现为双层，这与实验结果一致。尽管头基相互作用在生物学上非常重要，但在脂质主要相变的基础研究中，它们相对于烃链相互作用（包括排除体积相互作用、旋转异构和有吸引力的范德华相互作用）来说重要性次之。
