Kociurzynski Raisa, Pannuzzo Martina, Böckmann Rainer A
Computational Biology, Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 5, 91058 Erlangen, Germany.
Langmuir. 2015 Sep 1;31(34):9379-87. doi: 10.1021/acs.langmuir.5b01617. Epub 2015 Aug 19.
Glycolipids are important components of biological membranes. High concentrations of glycolipids are particularly found in lipid rafts, which take part in many physiological phenomena. This different partitioning and interaction pattern of glycolipids in the membrane as compared to those of phospholipids are likely due to their different chemical structures: the polar regions of glycosphingolipids can be even larger than for their hydrophobic moieties, giving rise to a rich conformational landscape. Here we study the influence of glycosphingolipids galactosylceramide (GCER) and monosialotetrahexosylganglioside (GM1) on the structural and thermodynamic properties of a phospholipid (DPPC) bilayer. Using the method of coarse-grained molecular dynamics simulation we show that both glycolipids increase the phase-transition temperature of phospholipid membranes and that the extent of this increase depends on the headgroup size and structure. GM1 shows a strong tendency to form mixed clusters with phospholipids, thereby stabilizing the membrane. In contrast, GCER is dispersed in the membrane. By occupying the interstitial space between phospholipids it causes a tighter packing of the lipids in the membrane.
糖脂是生物膜的重要组成部分。在脂筏中尤其发现高浓度的糖脂，脂筏参与许多生理现象。与磷脂相比，糖脂在膜中的这种不同的分配和相互作用模式可能是由于它们不同的化学结构：糖鞘脂的极性区域甚至可能比其疏水部分更大，从而产生丰富的构象景观。在这里，我们研究了糖脂半乳糖神经酰胺（GCER）和单唾液酸四己糖神经节苷脂（GM1）对磷脂（DPPC）双层结构和热力学性质的影响。使用粗粒化分子动力学模拟方法，我们表明这两种糖脂都会提高磷脂膜的相变温度，并且这种升高的程度取决于头基团的大小和结构。GM1表现出与磷脂形成混合簇的强烈倾向，从而稳定膜。相比之下，GCER分散在膜中。通过占据磷脂之间的间隙空间，它导致膜中脂质的堆积更紧密。
