Interaction of epicatechin gallate with phospholipid membranes as revealed by solid-state NMR spectroscopy
Interaction of epicatechin gallate with phospholipid membranes as revealed by solid-state NMR spectroscopy
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DOI：
10.1016/j.bbamem.2011.02.014
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发表时间：
2011-06-01
影响因子：
3.4
通讯作者：
Nakayama, Tsutornu
中科院分区：
文献类型：
--
作者：
Uekusa, Yoshinori;Kamihira-Lshijima, Miya;Nakayama, Tsutornu
表儿茶素没食子酸酯（Epicatechin gallate，ECg）是一种绿色茶多酚，具有多种生理作用。我们以前的核Overhauser效应光谱（NOESY）的研究，使用溶液NMR光谱表明，心电图强烈相互作用的磷脂双分子层的表面。然而，在磷脂双层的心电图的动态行为还没有得到澄清，特别是动力学和分子排列的没食子酰基部分，这被认为是一个重要的相互作用。在本研究中，我们合成了[（13）C]-ECg，其中没食子酰基部分的羰基碳被（13）C同位素标记，并通过固态NMR光谱对其进行分析。固态（31）P NMR分析表明，ECg改变了DMPC双层的凝胶到液晶的相变温度以及磷脂的动力学和流动性。在静态条件下的固态（13）C NMR分析中，[（13）C]-ECg的羰基碳信号表现出轴对称的粉末图案。这表明，心电图分子旋转轴倾斜在一个恒定的角度，双层正常。通过（13）C-（31）P旋转回波双共振（REDOR）测量，[（13）C]-ECG的标记羰基碳与磷脂磷之间的精确分子间-原子间距离为5.3 +/- 0.1埃。这些结果表明，没食子酰基部分有助于增加儿茶素分子的疏水性，并因此高亲和力的没食子酰基型儿茶素磷脂膜，以及稳定的儿茶素分子在磷脂膜之间的阳离子π相互作用的没食子酰基环和季胺的磷脂头基。(C)2011 Elsevier B. V.保留所有权利。
Epicatechin gallate (ECg), a green tea polyphenol, has various physiological effects. Our previous nuclear Overhauser effect spectroscopy (NOESY) study using solution NMR spectroscopy demonstrated that ECg strongly interacts with the surface of phospholipid bilayers. However, the dynamic behavior of ECg in the phospholipid bilayers has not been clarified, especially the dynamics and molecular arrangement of the galloyl moiety, which supposedly has an important interactive role. In this study, we synthesized [(13)C]-ECg, in which the carbonyl carbon of the galloyl moiety was labeled by (13)C isotope, and analyzed it by solid-state NMR spectroscopy. Solid-state (31)P NMR analysis indicated that ECg changes the gel-to-liquid-crystalline phase transition temperature of DMPC bilayers as well as the dynamics and mobility of the phospholipids. In the solid-state (13)C NMR analysis under static conditions, the carbonyl carbon signal of the [(13)C]-ECg exhibited an axially symmetric powder pattern. This indicates that the ECg molecules rotate about an axis tilting at a constant angle to the bilayer normal. The accurate intermolecular-interatomic distance between the labeled carbonyl carbon of [(13)C]-ECg and the phosphorus of the phospholipid was determined to be 5.3 +/- 0.1 angstrom by (13)C-(31)P rotational echo double resonance (REDOR) measurements. These results suggest that the galloyl moiety contributes to increasing the hydrophobicity of catechin molecules, and consequently to high affinity of galloyl-type catechins for phospholipid membranes, as well as to stabilization of catechin molecules in the phospholipid membranes by cation-pi interaction between the galloyl ring and quaternary amine of the phospholipid head-group. (C) 2011 Elsevier B.V. All rights reserved.