Aggregate formation of gangliosides at low concentrations in aqueous media

The gangliosides GLac1, GGtri1 and GGtet1 in aqueous medium sediment in the ultracentrifuge as oligomeric aggregates independent of concentration at 10(-3)M to 10(-9)M with the sedimentation constants S20,W of 5.3, 7.5 and 10.0, respectively. If gangliosides dissolved in dimethylsulfoxide were diluted with water, this resulted in aggregates with lower sedimentation coefficients. In the presence of 1M tetramethylurea no sedimentation of gangliosides could be observed in the ultracentrifuge. A ganglioside analogue (gangliosidoide) with two hydrocarbon chains instead of the ceramide moiety shows a similar sedimentation behaviour as the native compound GGtet1. However, a ganglioside analogue with only one aliphatic hydrocarbon chain forms sedimenting aggregates only at concentrations exceeding 10(-3)M.