Mattai J, Hauser H, Demel R A, Shipley G G
Laboratorium für Biochemie, Eidgenössische Technische Hochschule Zürich, Switzerland.
Biochemistry. 1989 Mar 7;28(5):2322-30. doi: 10.1021/bi00431a051.
A combination of surface monolayer, scanning calorimetry, 31P NMR, and spin-label ESR techniques has been used to monitor the interactions of monovalent (NH4+, Na+, and Li+) and divalent (Ca2+) cations with phosphatidylserines (PS) differing in their levels of chain unsaturation. Comparisons are made between the disaturated dimyristoyl-, dipalmitoyl-, and dihexadecyl-PS (DMPS, DPPS, and DHPS), saturated cis-monounsaturated palmitoyloleoyl-PS (POPS) (and bovine brain PS), di-trans-monounsaturated dielaidoyl-PS (DEPS), and di-cis-monounsaturated dioleoyl-PS (DOPS). Na+ and NH4+ cations interact weakly with all PS monolayers and bilayers without significant changes in molecular conformation, chain packing, or headgroup dynamics and without dependence on chain composition. In contrast, considering these structural and dynamic parameters, Li+ shows a gradation in its interaction with PS (DMPS greater than POPS approximately bovine brain PS greater than DOPS), suggesting that Li+-PS interactions depend on the interfacial properties of the PS molecules (e.g., surface area). Finally, Ca2+ interacts strongly with all PS monolayers and bilayers, without obvious chain selectivity. Thus, ion binding to PS depends not only on the properties of the cation (Na+ vs Li+ vs Ca2+) but also on the molecular details of the PS membrane surface.
采用表面单层、扫描量热法、31P核磁共振和自旋标记电子顺磁共振技术相结合的方法，监测单价阳离子（NH4+、Na+和Li+）和二价阳离子（Ca2+）与链不饱和度不同的磷脂酰丝氨酸（PS）之间的相互作用。对二饱和的二肉豆蔻酰基-、二棕榈酰基-和二十六烷基-PS（DMPS、DPPS和DHPS）、饱和顺式单不饱和棕榈酰油酰-PS（POPS）（以及牛脑PS）、二反式单不饱和二油酰基-PS（DEPS）和二顺式单不饱和二油酰基-PS（DOPS）进行了比较。Na+和NH4+阳离子与所有PS单层和双层的相互作用较弱，分子构象、链堆积或头部基团动力学没有显著变化，且不依赖于链组成。相比之下，考虑到这些结构和动力学参数，Li+与PS的相互作用呈现出一种梯度变化（DMPS大于POPS约等于牛脑PS大于DOPS），这表明Li+-PS相互作用取决于PS分子的界面性质（例如表面积）。最后，Ca2+与所有PS单层和双层都有强烈相互作用，没有明显的链选择性。因此，离子与PS的结合不仅取决于阳离子的性质（Na+与Li+与Ca2+），还取决于PS膜表面的分子细节。
