PHYSICOCHEMICAL BEHAVIOR OF THE GANGLIOSIDE GM3 IN DILUTE AQUEOUS-SOLUTIONS

The aggregative properties of the ganglioside GM3 have been studied wi th small-angle X-ray scattering and dynamic light scattering in dilute aqueous solutions. Dynamic light scattering experiments show that GM3 solutions are very polydisperse containing a large amount of small ag gregates (hydrodynamic radius of 7-9 nm) in addition to a quite broad distribution of aggregates with an average hydrodynamic radius of. 50- 60 nm and a small fraction of very large aggregates (> 200 nm). This t ogether with small-angle X-ray scattering experiments and model calcul ations suggests the coexistence of a lamellar phase (vesicles or exten ded lamellae) with small aggregates (modelled as lamellar platelets). The latter can also be viewed as lamellar fragments coming from GM3 ve sicles which constantly break and reform.