Lipid bilayers containing sphingomyelins and ceramides of varying N-acyl lengths: A glimpse into sphingolipid complexity
Lipid bilayers containing sphingomyelins and ceramides of varying N-acyl lengths: A glimpse into sphingolipid complexity
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DOI：
10.1016/j.bbamem.2013.10.010
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发表时间：
2014-01-01
影响因子：
3.4
通讯作者：
Goni, Felix M.
中科院分区：
文献类型：
--
作者：
Jimenez-Rojo, Noemi;Garcia-Arribas, Aritz B.;Goni, Felix M.
N-酰基链从 C6:0 到 C24:1 的鞘磷脂 (SM) 和神经酰胺 (Cer) 的水分散体（纯的或二元混合物）的热致性质已通过差示扫描量热法进行了检查。即使在纯净状态下，Cer，特别是 SM 也表现出复杂的吸热现象，并且它们的热性质不会随着结构的变化而以可预测的方式变化。在某些情况下，例如C18:0 SM，原子力显微镜揭示了由单一脂质组成的共存层状结构域。部分链交错和亚稳态结晶状态被认为是造成复杂行为的原因。 SM:Cer 混合物（90:10 摩尔比）产生含有单独的富含 SM 和富含 Cer 结构域的双层。在由更复杂的混合物（SM:PE:Chol，2:1:1）制成的囊泡中，已知 SM 鞘磷脂酶降解为 Cer 伴随着囊泡聚集和水性内容物的释放。这些囊泡没有通过共焦显微镜观察到可观察到的域分离。根据差示扫描量热法，对于那些看起来更具流动性的双层，囊泡聚集以更快的速度发生。通过荧光光谱法测得的 C18:0 和 C18:1 SM 的含量流出率最高，并且一般来说，这些速率不会随 SM 或 Cer 的其他物理性质发生规律变化。一般来说，单独的 SM 和 Cer 似乎具有特定的热致性质，通常与 N-酰基链的变化无关。 (C) 2013 Elsevier B.V. 保留所有权利。
The thermotropic properties of aqueous dispersions of sphingomyelins (SM) and ceramides (Cer) with N-acyl chains varying from C6:0 to C24:1, either pure or in binary mixtures, have been examined by differential scanning calorimetry. Even in the pure state, Cer and particularly SM exhibited complex endotherrns, and their thermal properties did not vary in a predictable way with changes in structure. In some cases, e.g. C18:0 SM, atomic force microscopy revealed coexisting lamellar domains made of a single lipid. Partial chain interdigitation and metastable crystalline states were deemed responsible for the complex behavior. SM:Cer mixtures (90:10 mol ratio) gave rise to bilayers containing separate SM-rich and Cer-rich domains. In vesicles made of more complex mixtures (SM:PE:Chol, 2:1:1), it is known that sphingomyelinase degradation of SM to Cer is accompanied by vesicle aggregation and release of aqueous contents. These vesicles did not reveal observable domain separation by confocal microscopy. Vesicle aggregation occurred at a faster rate for those bilayers that appeared to be more fluid according to differential scanning calorimetry. Content efflux rates measured by fluorescence spectroscopy were highest with C18:0 and C18:1 SM, and in general those rates did not vary regularly with other physical properties of SM or Cer. In general the individual SM and Cer appear to have particular thermotropic properties, often unrelated to the changes in N-acyl chain. (C) 2013 Elsevier B.V. All rights reserved.