Glycosphingolipid headgroup orientation in fluid phospholipid/cholesterol membranes: similarity for a range of glycolipid fatty acids.
Glycosphingolipid headgroup orientation in fluid phospholipid/cholesterol membranes: similarity for a range of glycolipid fatty acids.
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流体磷脂/胆固醇膜中的鞘糖脂头基方向：一系列糖脂脂肪酸的相似性。
DOI：
10.1016/s0006-3495(95)79969-6
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发表时间：
1995
影响因子：
3.4
通讯作者：
C. Grant
中科院分区：
文献类型：
--
作者：
M. Morrow;D. Singh;C. Grant
通过用氘取代半乳糖残基C6处的氢原子来标记半乳糖基神经酰胺（GalCer）用于核磁共振（NMR）光谱。[d1]GalCer的Wideline 2 H NMR允许考虑传统上用于细胞表面识别位点调节的机制：连接到鞘糖脂（GSL）的鞘氨醇骨架上的脂肪酸的性质重要地影响碳水化合物头基方向。通过改变羟基化、饱和度和链长，在各种糖脂脂肪酸之间进行比较。在模拟细胞质膜几个重要特征的非超声处理双层膜中进行了研究：流动性、低GSL含量、主要的[sn-2]单不饱和磷脂酰胆碱（PC）（1-棕榈酰-2-油酰PC）和胆固醇的存在。在一定温度范围内对样品进行光谱分析，包括生理温度。具有18-碳饱和脂肪酸（硬脂酸）、顺式-9-不饱和脂肪酸（油酸）、α-OH硬脂酸的D-和L-立体异构体或24-碳饱和脂肪酸（二十四烷酸）的[d1]GalCer的2 H NMR谱重要地相似。这表明，GSL作为次要成分分散在流体膜中，糖脂脂肪酸的变化并不像有时假设的那样为碳水化合物部分的直接构象调节提供尽可能多的潜力。然而，有一些证据表明，所研究的物种之间的运动差异。所获得的2 H NMR谱证明比预期的更复杂。它们的特征可以通过假设轴对称和轴不对称糖脂运动的组合来近似。假设适当的这样一个分析，在3.54 T（23.215 MHz）的磁场，实验光谱建议主要是不对称的运动的贡献。在11.7 T（76.7 MHz，相当于500 MHz的质子频率）的较高的字段，光谱表示轴对称旋转模式的优势。在较强的磁场中也有一些双层取向的证据。两种磁场强度之间光谱差异的异常观察可能涉及某些脂质体物理特性对高场的抗磁性响应。
Galactosyl ceramide (GalCer) was labeled for nuclear magnetic resonance (NMR) spectroscopy by replacement of a hydrogen atom at C6 of the galactose residue with deuterium. Wideline 2H NMR of [d1]GalCer permitted consideration of a mechanism traditionally entertained for cell surface recognition site modulation: that the nature of the fatty acid attached to the sphingosine backbone of glycosphingolipids (GSLs) importantly influences carbohydrate headgroup orientation. Comparison was made among various glycolipid fatty acids by altering hydroxylation, saturation, and chain length. Studies were carried out in unsonicated bilayer membranes mimicking several important characteristics of cell plasma membranes: fluidity, low GSL content, predominant [sn-2]monounsaturated phosphatidylcholine (PC) (1-palmitoyl-2-oleoyl PC), and the presence of cholesterol. Spectroscopy was performed on samples over a range of temperatures, which included the physiological. 2H NMR spectra of [d1]GalCer having 18-carbon saturated fatty acid (stearic acid), cis-9-unsaturated fatty acid (oleic acid), D- and L-stereoisomers of alpha-OH stearic acid, or 24-carbon saturated fatty acid (lignoceric acid) were importantly similar. This argues that for GSLs dispersed as minor components in fluid membranes, variation of the glycolipid fatty acid does not provide as much potential for direct conformational modulation of the carbohydrate portion as has sometimes been assumed. However, there was some evidence of motional differences among the species studied. The 2H NMR spectra that were obtained proved to be more complex than was anticipated. Their features could be approximated by assuming a combination of axially symmetric and axially asymmetric glycolipid motions. Presuming the appropriateness of such a analysis, at a magnetic field of 3.54 T (23.215 MHz), the experimental spectra suggested predominantly asymmetric motional contributions. At the higher field of 11.7 T (76.7 MHz, equivalent to a proton frequency of 500 MHz), spectra indicated dominance by axially symmetric rotational modes. There was also evidence of some bilayer orientation in the stronger magnetic field. The unusual observation of spectral differences between the two magnetic field strengths may involve a diamagnetic response to high field on the part of some liposome physical characteristics.
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DOI：
10.1016/0005-2736(93)90316-r
发表时间：
1993
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Qiu,X;Mirau,PA;Pidgeon,C
通讯作者：
Pidgeon,C
链不饱和度对半乳脑苷脂结构和热致性质的影响。
影响因子：
3.4
作者：
Reed,RA;Shipley,GG
通讯作者：
Shipley,GG
影响因子：
--
作者：
Griffin,RG
通讯作者：
Griffin,RG
牛脑半乳糖脑苷脂的相行为。
影响因子：
2.9
作者：
Curatolo,W;Jungalwala,FB
通讯作者：
Jungalwala,FB
影响因子：
--
作者：
S. Hakomori
通讯作者：
S. Hakomori