MEMPHYS-Center for Biomembrane Physics, Department of Physics and Chemistry, University of Southern Denmark, Odense, Denmark.
PLoS One. 2010 Sep 22;5(9):e12811. doi: 10.1371/journal.pone.0012811.
Triglycerides have a limited solubility, around 3%, in phosphatidylcholine lipid bilayers. Using millisecond-scale course grained molecular dynamics simulations, we show that the model lipid bilayer can accommodate a higher concentration of triolein (TO) than earlier anticipated, by sequestering triolein molecules to the bilayer center in the form of a disordered, isotropic, mobile neutral lipid aggregate, at least 17 nm in diameter, which forms spontaneously, and remains stable on at least the microsecond time scale. The results give credence to the hotly debated existence of mobile neutral lipid aggregates of unknown function present in malignant cells, and to the early biogenesis of lipid droplets accommodated between the two leaflets of the endoplasmic reticulum membrane. The TO aggregates give the bilayer a blister-like appearance, and will hinder the formation of multi-lamellar phases in model, and possibly living membranes. The blisters will result in anomalous membrane probe partitioning, which should be accounted for in the interpretation of probe-related measurements.
甘油三酯在磷脂酰胆碱脂质双层中的溶解度有限，约为 3%。通过使用毫秒级的粗粒分子动力学模拟，我们表明模型脂质双层可以容纳比早先预期更高浓度的三油酸甘油酯（TO），方法是将三油酸甘油酯分子以无序、各向同性、可移动的中性脂质聚集体的形式隔离到双层中心，其直径至少为 17nm，这种聚集体自发形成，并至少在微秒时间尺度上保持稳定。该结果证实了恶性细胞中存在功能未知的、可移动的中性脂质聚集体这一激烈争论的存在，以及内质网膜两叶之间容纳的脂质滴的早期生物发生。TO 聚集体使双层具有泡状外观，并将阻碍模型和可能的活细胞膜中多层层相的形成。泡状结构将导致膜探针分配出现异常，这在解释与探针相关的测量时应加以考虑。
