Ganglioside–basic protein interaction: Protection of gangliosides against neuraminidase action

The ability of acidic phospho‐ and sphingolipids to interact with basic proteins was studied by double diffusion analysis. The phospholipids, tri‐ and diphosphoinositide, and the sphingolipid, sulfatide, interacted with myelin basic protein as evidenced by precipitin line formation. Of the sialoglycosphingolipids (gangliosides) tested, only the myelin‐specific monosialoganglioside, GM4 The ganglioside nomenclature used here is according to the system of Svennerholm [1963]. The gangliosides are designated as follows: GM4 = I3NeuAcGalCer; GM3 = II3NeuAcLacCer; GM1 = II3NeuAcGgOse4Cer; GD1a = IV3 NeuAc, II3NeuAcGgOse4Cer; GD1b = II3(NeuAc)2GgOse4Cer; and GT1b = IV3NeuAc, II3(NeuAc)2GgOse4Cer. , formed a precipitin line with myelin basic protein. In addition, myelin basic protein retarded the activity of Clostridium perfringens neuraminidase against GM4 and the disialoganglioside, GD1b. Examination of purified rat brain myelin suggested the presence of a neuraminidase activity intrinsic to myelin. This finding, in concert with ganglioside‐myelin basic protein complexes which selectively protect against neuraminidase, may provide a physiological explanation for the simplified ganglioside pattern found in myelin.