Song W X, Rintoul D A
Division of Biology, Kansas State University, Manhattan 66506.
Biochemistry. 1989 May 16;28(10):4194-200. doi: 10.1021/bi00436a011.
N-cis-Parinaroyl ganglioside GM1 and N-trans-parinaroyl ganglioside GM1 were synthesized and characterized by HPLC, TLC, component analysis, absorbance spectroscopy, and proton NMR spectroscopy. Steady-state fluorescence anisotropy of the purified compounds, incorporated into phosphatidylcholine liposomes, was measured in the presence and absence of choleragen (cholera toxin) and choleragenoid (cholera toxin B subunit). In gel-phase liposomes, anisotropy measurements indicated that the motion of the parinaroyl ganglioside was not affected by addition of choleragen or choleragenoid. In fluid-phase liposomes, however, addition of toxin resulted in increased anisotropy (decreased rotational motion) of the fluorescent gangliosides. This decreased motion was not observed with other parinaroyl lipid probes, such as phosphatidylcholine, glucosylceramide, or free fatty acids, indicating that the effect was due to specific ganglioside/toxin interactions. Varying the amount of ganglioside or the amount of toxin suggested that the effect of toxin on probe motion was saturable at approximately 1 choleragen (or choleragenoid) molecule/5 ganglioside molecules. These results are consistent with previous hypotheses regarding the ganglioside/choleragen interaction and indicate that parinaroyl ganglioside probes will be useful in elucidation of the molecular details of this interaction.
合成了N-顺式-十八碳四烯酰神经节苷脂GM1和N-反式-十八碳四烯酰神经节苷脂GM1，并通过高效液相色谱（HPLC）、薄层色谱（TLC）、成分分析、吸收光谱和质子核磁共振光谱对其进行了表征。在有和没有霍乱毒素和霍乱类毒素（霍乱毒素B亚基）存在的情况下，对掺入磷脂酰胆碱脂质体中的纯化化合物进行了稳态荧光各向异性测量。在凝胶相脂质体中，各向异性测量表明，十八碳四烯酰神经节苷脂的运动不受霍乱毒素或霍乱类毒素添加的影响。然而，在液相脂质体中，毒素的添加导致荧光神经节苷脂的各向异性增加（旋转运动减少）。使用其他十八碳四烯酰脂质探针，如磷脂酰胆碱、葡萄糖神经酰胺或游离脂肪酸，未观察到这种运动减少，这表明该效应是由于特定的神经节苷脂/毒素相互作用所致。改变神经节苷脂的量或毒素的量表明，毒素对探针运动的影响在大约1个霍乱毒素（或霍乱类毒素）分子/5个神经节苷脂分子时达到饱和。这些结果与先前关于神经节苷脂/霍乱毒素相互作用的假设一致，并表明十八碳四烯酰神经节苷脂探针将有助于阐明这种相互作用的分子细节。
