Interaction of gangliosides with proteins depending on oligosaccharide chain and protein surface modification.
By using neutron and synchrotron x-ray small-angle scattering techniques, we investigated the process of the complexation of gangliosides with proteins. We treated monosialoganglioside (G(M1)), disialoganglioside (G(D1a)), and a mixture of G(M1)/G(D1a). Proteins used were bovine serum albumins whose surfaces were modified with different sugars (deoxy-D-galactose, deoxy-L-fucose, deoxymaltitol, and deoxycellobiitol), which were used as model glycoproteins in a membrane. We found that the complexation of gangliosides with albumins greatly depends on the combination of ganglioside species and protein surface modification. With a varying protein/ganglioside ratio in a buffer solution at pH 7, the complexation of G(M1) or G(D1a) with albumins modified by monosaccharides appears to be less destructive for ganglioside aggregate structures in forming large complexes; the complexation of G(D1a) with the albumins modified by disaccharides induces the formation of complexes with a dimeric structure; and the complexation of G(M1) with albumins modified by disaccharides, to form small complexes, is very destructive. The present results show a strong dependence of the interaction between ganglioside and protein on the characteristics of the ganglioside and protein surface, which would relate to a physiological function of gangliosides, such as a function regulating the receptor activity of glycoproteins in a cell membrane.
Hirai
M
M
Department of Physics, Gunma University, Maebashi, Japan. hirai@sun.aramaki.gunma-u.ac.jp
Iwase
H
H
Arai
S
S
Takizawa
T
T
Hayashi
K
K
D000818:Animals; D001665:Binding Sites; D001921:Brain; D002240:Carbohydrate Sequence; D002417:Cattle; D005677:G(M1) Ganglioside / Q000737:chemistry / Q000378:metabolism; D005732:Gangliosides / Q000737:chemistry* / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009502:Neutrons; D012542:Scattering, Radiation; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D017356:Synchrotrons; D014965:X-Rays
D005732:Gangliosides; D006023:Glycoproteins; C021298:ganglioside, GD1a; D012710:Serum Albumin, Bovine; D005677:G(M1) Ganglioside