Structural analysis and functional role of the carbohydrate component of glycine transporter.

摘要: Abstract The sodium- and chloride-coupled glycine transporter from pig brain stem has been shown to be a 100-kDa glycoprotein (Lopez-Corcuera, B., Vazquez, J., Aragon, C. (1991) J. Biol. Chem. 266, 24809-24814). To structurally identify the carbohydrate components of transporter, purified radioiodinated protein was subjected specific glycosidase treatments. When treated with peptide-N-glycosidase F (PNGaseF) remove N-linked oligosaccharides, significant reduction apparent molecular mass observed. However, incubations endoglycosidase O-glycanase did not affect electrophoretic mobility protein, neuraminidase produced slight its mass. effect PNGaseF indicates that sugar chains represent about 30% this heavily glycosylated transporter. deglycosylated form is recognized by previously characterized anti-100-kDa antiserum Alcantara, R., (1993) 268, 2239-2243), suggesting epitopes are in peptidic part glycoprotein. These other results suggest transporter-linked carbohydrates predominantly tri- or tetra- antennary complex oligosaccharides containing sialic acid residues. investigate functional role moiety, liposomes reconstituted were treatments, on transport activity tested. Whereas treatment drastic activity. This two different species, N-glycosylation sites would occupied native protein. studies arise as first evidence supporting notion play relevant functionality.