Calculation of the conformation of glycosphingolipids. 2. GM1- and GM2-gangliosides

The conformations of GM1- and GM2-gangliosides have been predicted by energy minimization techniques including an orbital force field approach. The global energy minimum conformers for these two gangliosides show marked differences, particularly in the relative orientation of the sugar rings. The predicted structures are compared with those postulated from NMR spectroscopy in relation to the formation of a cation-binding site. The minimum energy conformer of GM2-ganglioside is able to form this binding site whereas this conformer of GM1-ganglioside is not. The nature of the specific interaction of gangliosides with activator proteins is discussed.