Kataoka R, Aruga S, Mitaku S, Kinosita K, Ikegami A
Biophys Chem. 1985 Mar;21(3-4):277-84. doi: 10.1016/0301-4622(85)80015-6.
The effect of Ca2+ on the molecular mobility in dipalmitoylphosphatidylcholine membranes was studied by steady-state and time-resolved measurements of fluorescence anisotropy. The fluorescence anisotropy decay of 1,6-diphenyl-1,3,5-hexatriene in the hydrocarbon region indicated that the free volume of molecular rotation became more restricted when the Ca2+ concentration was increased. The decrease of the molecular mobility was observed from 1 mM Ca2+, at which the number of bound Ca2+ is much less than that of the total lipid molecules. A distinct difference between Ca2+ and Mg2+ effects suggested that the change in various membrane properties was induced by the binding of these ions. From these results we propose a long-range attractive interaction between bound Ca2+ and the polar head groups of distant phosphatidylcholine molecules.
通过稳态和时间分辨荧光各向异性测量，研究了Ca2+对二棕榈酰磷脂酰胆碱膜中分子流动性的影响。烃区域中1,6-二苯基-1,3,5-己三烯的荧光各向异性衰减表明，当Ca2+浓度增加时，分子旋转的自由体积变得更加受限。从1 mM Ca2+开始观察到分子流动性降低，此时结合的Ca2+数量远少于总脂质分子数量。Ca2+和Mg2+效应之间的明显差异表明，这些离子的结合诱导了各种膜性质的变化。根据这些结果，我们提出结合的Ca2+与远处磷脂酰胆碱分子的极性头部基团之间存在长程吸引相互作用。
