Hexagonal Substructure and Hydrogen Bonding in Liquid-Ordered Phases Containing Palmitoyl Sphingomyelin.
Hexagonal Substructure and Hydrogen Bonding in Liquid-Ordered Phases Containing Palmitoyl Sphingomyelin.
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DOI：
10.1016/j.bpj.2015.07.036
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发表时间：
2015-09
影响因子：
3.4
通讯作者：
A. Sodt;R. Pastor;E. Lyman
中科院分区：
文献类型：
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作者：
A. Sodt;R. Pastor;E. Lyman
提供了棕榈酰鞘磷脂 (PSM)、胆固醇和棕榈酰油酰磷脂酰胆碱或二油酰磷脂酰胆碱 (DOPC) 的三元混合物的全原子模拟数据。为了进行比较，还提供了二棕榈酰磷脂酰胆碱 (DPPC)、胆固醇和 DOPC 混合物的数据。对于每种混合物，模拟了对应于液体有序相、液体无序相以及两相共存的组成。在液态有序相中，如果有 DOPC，胆固醇会优先被 DOPC 溶剂化，但如果 DOPC 被 POPC 取代，胆固醇会优先被 PSM 溶剂化。在 DPPC 混合物中，胆固醇优先通过其光滑表面与饱和链相互作用，而在 PSM 混合物中，胆固醇优先通过其粗糙表面与 PSM 相互作用。胆固醇和 PSM 之间的相互作用具有非常特殊的特征：胆固醇和 PSM 酰胺之间的氢键会旋转酰胺平面的倾斜度，从而使其与其他 PSM 形成更牢固的氢键。胆固醇-PSM 氢键还局部改变 PSM 混合物液相有序相中烃链的六方堆积。
All-atom simulation data are presented for ternary mixtures of palmitoyl sphingomyelin (PSM), cholesterol, and either palmitoyl oleoyl phosphatidyl choline or dioleoyl phosphatidyl choline (DOPC). For comparison, data for a mixture of dipalmitoyl phosphatidyl choline (DPPC), cholesterol, and DOPC are also presented. Compositions corresponding to the liquid-ordered phase, the liquid-disordered phase, and coexistence of the two phases are simulated for each mixture. Within the liquid-ordered phase, cholesterol is preferentially solvated by DOPC if it is available, but if DOPC is replaced by POPC, cholesterol is preferentially solvated by PSM. In the DPPC mixtures, cholesterol interacts preferentially with the saturated chains via its smooth face, whereas in the PSM mixtures, cholesterol interacts preferentially with PSM via its rough face. Interactions between cholesterol and PSM have a very particular character: hydrogen bonding between cholesterol and the amide of PSM rotates the tilt of the amide plane, which primes it for more robust hydrogen bonding with other PSM. Cholesterol-PSM hydrogen bonding also locally modifies the hexagonal packing of hydrocarbon chains in the liquid-ordered phase of PSM mixtures.