Glycolipid Induced Change in Liposomal Microviscosity

We have studied the effect of sheep brain ganglioside on the fluidity profile of lecithin liposome. The study, using a fluorescent polarization probe, indicates that lipid molecules are inttermixed completely, thereby attaining a homogeneous system with a fluidity profile of its own. Similar result is obtained using galactocerebroside in the lacithin liposome. However, when desialated gangliosides are used instead, evidence of multiple phase transitions is obtained in the mixed system, indicating a glycosidated binding in the sugar moiety, leading to phase separation. The presence of ganglioside does not affect to a large extent the "intermediate fluid condition" induced by cholesterol in the lecithin liposome. The study indicates that intemixing of lipids takes place due to the sialic acid component of the ganglioside and interaction between ganglioside and other receptors gets modified when the former is embedded in the biological membrane.