Molecular parameters and conformation of globoside and asialo-GM1.
Molecular parameters and conformation of globoside and asialo-GM1.
复制标题
globoside 和 asialo-GM1 的分子参数和构象。
DOI：
10.1016/0003-9861(85)90355-8
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发表时间：
1985
影响因子：
3.9
通讯作者：
Yu,RK
中科院分区：
文献类型：
--
作者：
Maggio,B;Ariga,T;Yu,RK
采用脂质单层和高灵敏度差示扫描量热法对去唾液酸-GM 1（Gg 4Cer）和globoside（Gb 4Cer）的个体性质和分子间组织进行了比较研究。Gb 4Cer的表面压力-面积等温线比Gg 4Cer的表面压力-面积等温线扩展得更大。这导致在更大的分子面积和压缩，和较低的分子间相互作用能，为Gb 4Cer相比，在所有的表面压力Gg 4Cer。这种松散的分子间堆积可能是导致Gb 4Cer相变的转变温度（40.5 °C）和转变焓（ΔHcal）（2.0 kcal mol−1）低于Gg 4Cer（54.0 °C和4.2 kcal mol−1）的原因。每个分子的表面电位和由此产生的分子偶极矩矢量值是更大的Gb 4Cer比Gg 4Cer在表面压力和分子面积的可比值。所有这些结果反映了Gb 4Cer的寡糖链中存在刚性L形，与Gg 4Cer的极性头部基团的直取向相比，其防止了紧密的分子间堆积。取决于侧表面压力，寡糖链可能发生显著移动。在低表面压力下，与在高表面压力下采用的垂直位置相比，Gg 4Cer的寡糖链的取向可以移位高达约40 °的角度。与界面的增强的液体特性一致，Gb 4Cer的寡糖链表现出更大的运动自由度，并且从垂直于界面的位置的位移可以达到约65 °。
Comparative studies of the individual properties and intermolecular organization of asialo-GM1(Gg4Cer) and globoside (Gb4Cer) were made employing lipid monolayers and high-sensitivity differential scanning calorimetry. The surface pressure-area isotherm of Gb4Cer is more expanded than that of Gg4Cer. This results in greater molecular areas and compressibilities, and lower intermolecular interaction energies, for Gb4Cer compared to Gg4Cer at all surface pressures. This looser intermolecular packing may be responsible for a lower transition temperature (40.5 °C) and enthalpy of transition (ΔHcal) (2.0 kcal mol−1) found for the phase transition of Gb4Cer compared to Gg4Cer (54.0 °C and 4.2 kcal mol−1). The surface potential per molecule and resultant molecular dipole moment vector values are greater for Gb4Cer than for Gg4Cer at comparable values of surface pressure and molecular area. All these results reflect the existence of a rigid L-shape in the oligosaccharide chain of Gb4Cer that prevents a close intermolecular packing compared to the straight orientation of the polar head group of Gg4Cer. Significant movements of the oligosaccharide chain may occur depending on the lateral surface pressure. At low surface pressures the orientation of the oligosaccharide chain of Gg4Cer may be displaced an angle of up to about 40 ° compared to the perpendicular position adopted at high surface pressures. In agreement with an enhanced liquid character of the interface, the oligosaccharide chain of Gb4Cer exhibits a greater freedom of movement and the displacement from the position perpendicular to the interface can reach to about 65 °.