Thermodynamic comparison of the interactions of cholesterol with unsaturated phospholipid and sphingomyelins.
Thermodynamic comparison of the interactions of cholesterol with unsaturated phospholipid and sphingomyelins.
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胆固醇与不饱和磷脂和鞘磷脂相互作用的热力学比较。
DOI：
10.1529/biophysj.105.080127
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发表时间：
2006
影响因子：
3.4
通讯作者：
H. Heerklotz
中科院分区：
文献类型：
--
作者：
Alekos D Tsamaloukas;Halina Szadkowska;H. Heerklotz
胆固醇（Chol）与棕榈酰-油酰-磷脂酰胆碱（POPC）和鞘磷脂（SM）的相互作用的比较分析是在50 ℃下在基本均匀的液相膜中进行的。为此，三个独立的测定等温滴定量热法应用于POPC/SM/胆固醇混合物。通过随机甲基化-β-环糊精溶解胆固醇，并测量Chol摄取到大单层囊泡中（或从大单层囊泡释放）。Chol与含30 mol % Chol的POPC/SM（1：1）膜的亲和力约为单独POPC的两倍;外推至纯SM产生的亲和力比R（K）约为5。使Chol与SM接触是高度放热的（与POPC相比，POPC/SM（1：1）为-7kJ/mol，并且外推至纯SM为-13kJ/mol）。在鸡蛋、牛脑和棕榈酰SM之间未观察到显著差异。随着Chol含量的降低，R（K）增加，并且Δ H变得更加放热，表明超晶格形成的趋势。SM/Chol-相互作用在化学上是有利的，这意味着Chol对SM的偏好在冷却时增加，并且可以在低于一定温度时诱导畴形成。根据Chol诱导的链有序的概念，焓增益部分地由熵损失补偿，这改善了分子间相互作用（货车德瓦尔斯，H-键），但降低了构象和运动自由度。环糊精从膜中提取鞘磷脂的能力比POPC弱两倍。
A comparative analysis of the interaction of cholesterol (Chol) with palmitoyl-oleoyl-phosphatidylcholine (POPC) and sphingomyelins (SM) was performed in largely homogeneous, fluid-phase membranes at 50 degrees C. To this end, three independent assays for isothermal titration calorimetry were applied to POPC/SM/Chol mixtures. Cholesterol is solubilized by randomly methylated-beta-cyclodextrin and the uptake of Chol into (or release from) large unilamellar vesicles is measured. The affinity of Chol to a POPC/SM (1:1) membrane with 30 mol % Chol is approximately two times higher than to POPC alone; extrapolation to pure SM yields an affinity ratio of R(K) approximately 5. Bringing Chol in contact with SM is highly exothermic (-7 kJ/mol for POPC/SM (1:1), and -13 kJ/mol extrapolated to pure SM, both compared to POPC). No pronounced differences were observed between egg, bovine brain, and palmitoyl SM. With decreasing Chol content, R(K) increases and deltaH becomes more exothermic, suggesting a trend toward superlattice formation. That SM/Chol-interactions are enthalpically favorable implies that the preference of Chol for SM increases upon cooling and can induce domain formation below a certain temperature. The enthalpy gain is partially compensated by a loss in entropy in accordance with the concept of Chol-induced chain ordering, which improves intermolecular interactions (van der Waals, H-bond) but reduces conformational and motional freedom. The ability of cyclodextrin to extract sphingomyelin from membranes is twofold-weaker than for POPC.
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影响因子：
3.4
作者：
Guo, W;Kurze, V;Hamilton, JA
通讯作者：
Hamilton, JA
影响因子：
2.9
作者：
M. Sankaram;T. E. Thompson
通讯作者：
M. Sankaram;T. E. Thompson
影响因子：
2.9
作者：
Melkonian, KA;Chu, T;Brown, DA
通讯作者：
Brown, DA
影响因子：
2.9
作者：
Maulik, PR;Shipley, GG
通讯作者：
Shipley, GG
影响因子：
6.5
作者：
A. E. Christian;M. Haynes;M. Phillips;G. Rothblat
通讯作者：
A. E. Christian;M. Haynes;M. Phillips;G. Rothblat