Gonzalez Miguel A, Barriga Hanna M G, Richens Joanna L, Law Robert V, O'Shea Paul, Bresme Fernando
Department of Chemistry, Imperial College London, SW7 2AZ, London, UK.
School of Life Sciences, University of Nottingham, Nottingham, UK.
Phys Chem Chem Phys. 2017 Mar 29;19(13):9199-9209. doi: 10.1039/c7cp01400g.
Lanthanide salts have been studied for many years, primarily in Nuclear Magnetic Resonance (NMR) experiments of mixed lipid-protein systems and more recently to study lipid flip-flop in model membrane systems. It is well recognised that lanthanide salts can influence the behaviour of both lipid and protein systems, however a full molecular level description of lipid-lanthanide interactions is still outstanding. Here we present a study of lanthanide-bilayer interactions, using molecular dynamics computer simulations, fluorescence electrostatic potential experiments and nuclear magnetic resonance. Computer simulations reveal the microscopic structure of DMPC lipid bilayers in the presence of Yb, and a surprising ability of the membranes to adsorb significant concentrations of Yb without disrupting the overall membrane structure. At concentrations commonly used in NMR experiments, Yb ions bind strongly to 5 lipids, inducing a small decrease of the area per lipid and a slight increase of the ordering of the aliphatic chains and the bilayer thickness. The area compressibility modulus increases by a factor of two, with respect to the free-salt case, showing that Yb ions make the bilayer more rigid. These modifications of the bilayer properties should be taken into account in the interpretation of NMR experiments.
镧系元素盐已经被研究多年，主要用于混合脂质 - 蛋白质系统的核磁共振（NMR）实验，最近也用于研究模型膜系统中的脂质翻转。人们已经充分认识到镧系元素盐会影响脂质和蛋白质系统的行为，然而，对脂质 - 镧系元素相互作用的完整分子水平描述仍然欠缺。在此，我们通过分子动力学计算机模拟、荧光静电势实验和核磁共振，对镧系元素 - 双层膜相互作用进行了研究。计算机模拟揭示了在镱（Yb）存在下二肉豆蔻酰磷脂酰胆碱（DMPC）脂质双层膜的微观结构，以及膜在不破坏整体膜结构的情况下吸附大量镱的惊人能力。在核磁共振实验常用的浓度下，镱离子与5种脂质强烈结合，导致每个脂质的面积略有减小，脂肪链的有序度和双层膜厚度略有增加。相对于自由盐的情况，面积压缩模量增加了一倍，表明镱离子使双层膜更具刚性。在解释核磁共振实验时，应考虑双层膜性质的这些变化。
