Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.
Effect of Anionic Lipids on Mammalian Plasma Cell Membrane Properties.
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DOI：
10.1021/acs.langmuir.2c03161
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发表时间：
2023-02-21
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研究了脂质组成对哺乳动物细胞膜内小叶模型的影响。掠入射x射线衍射和x射线和中子反射率被用来表征脂质堆积和溶剂化，而电化学和红外光谱方法被用来探测外加电场中的相行为。将少量阴离子脂质二肉豆烯酰基磷脂酰丝氨酸（DMPS）引入两性离子二肉豆烯酰基磷脂酰乙醇胺（DMPE）双层中，会导致双层对应用电场的响应发生显著变化：碳氢链的倾斜增加，然后在双层分离时恢复到原始倾斜角度。等摩尔混合物，具有更紧密的链式排列，表现出类似但较弱的反应。后者在电化学相变过程中也倾向于加入更多的溶剂，其水平与纯DMPS相似。反射率测量显示，DMPS的脂质层的溶剂化程度高于30mol %，这与富含dps的双分子层吸收水的更大倾向相匹配。综上所述，数据表明10-35 mol % DMPS的范围提供了最佳的双层特性（灵活性和屏障功能），这可以解释为什么细胞膜的DMPS含量往往在这个范围内。
The effect of lipid composition on models of the inner leaflet of mammalian cell membranes has been investigated. Grazing incidence X-ray diffraction and X-ray and neutron reflectivity have been used to characterize lipid packing and solvation, while electrochemical and infrared spectroscopic methods have been employed to probe phase behavior in an applied electric field. Introducing a small quantity of the anionic lipid dimyristoylphosphatidylserine (DMPS) into bilayers of zwitterionic dimyristoylphosphatidylethanolamine (DMPE) results in a significant change in the bilayer response to an applied field: the tilt of the hydrocarbon chains increases before returning to the original tilt angle on detachment of the bilayer. Equimolar mixtures, with slightly closer chain packing, exhibit a similar but weaker response. The latter also tend to incorporate more solvent during this electrochemical phase transition, at levels similar to those of pure DMPS. Reflectivity measurements reveal greater solvation of lipid layers for DMPS > 30 mol %, matching the greater propensity for DMPS-rich bilayers to incorporate water. Taken together, the data indicate that the range of 10–35 mol % DMPS provides optimum bilayer properties (in flexibility and function as a barrier), which may explain why the DMPS content of cell membranes tends to be found within this range.