Casal H L, Mantsch H H, Paltauf F, Hauser H
Biochim Biophys Acta. 1987 Jun 23;919(3):275-86. doi: 10.1016/0005-2760(87)90267-0.
Infrared and 31P-NMR spectra of solid samples of 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (DMPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS) and 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) have been recorded. Comparison of the spectra of the Na+ salts of these phospholipids with those of complexes formed with Li+ and Ca2+ ions allows the characterization of conformational changes induced by complexation with Li+ and Ca2+. Ca2+ forms tight, crystalline complexes with these phosphatidylserines (PS), irrespective of the degree of unsaturation in the hydrocarbon chains. In these PS-Ca2+ complexes the torsion angles of the two P-O ester bonds exhibit the antiplanar-antiplanar conformation which is significantly different from the standard gauche-gauche conformation commonly found in phosphodiesters. In contrast, complexation with Li+ does not induce this conformational change in the phosphodiester group. It is shown that the degree of unsaturation in the hydrocarbon chains, and related to it, the cross-sectional area of the phospholipid or the surface charge density, determine the affinity of the phosphatidylserine for the metal ion. In general, the affinity of phosphatidylserines for both Li+ and Ca2+ decreases with increasing unsaturation in the hydrocarbon chains or decreasing surface charge density; it is in the order DMPS greater than POPS greater than DOPS.
记录了1,2-二肉豆蔻酰基-sn-甘油-3-磷酸-L-丝氨酸（DMPS）、1-棕榈酰基-2-油酰基-sn-甘油-3-磷酸-L-丝氨酸（POPS）和1,2-二油酰基-sn-甘油-3-磷酸-L-丝氨酸（DOPS）固体样品的红外光谱和31P-核磁共振光谱。将这些磷脂的钠盐光谱与与Li+和Ca2+离子形成的配合物光谱进行比较，可以表征与Li+和Ca2+络合引起的构象变化。Ca2+与这些磷脂酰丝氨酸（PS）形成紧密的晶体配合物，与烃链中的不饱和度无关。在这些PS-Ca2+配合物中，两个P-O酯键的扭转角呈现反平面-反平面构象，这与磷酸二酯中常见的标准 gauche-gauche 构象有显著不同。相比之下，与Li+络合不会在磷酸二酯基团中诱导这种构象变化。结果表明，烃链中的不饱和度以及与之相关的磷脂横截面面积或表面电荷密度决定了磷脂酰丝氨酸对金属离子的亲和力。一般来说，磷脂酰丝氨酸对Li+和Ca2+的亲和力随着烃链不饱和度的增加或表面电荷密度的降低而降低；顺序为DMPS大于POPS大于DOPS。
