Title : Glycosylation
sites and site-specific glycosylation in human
Tamm-Horsfall glycoprotein
Abstract :
- The N-glycosylation sites of human Tamm-Horsfall glycoprotein from one healthy male donor have been characterized, based on an approach using endoproteinase Glu-C ( V-8 protease , Staphylococcus aureus ) digestion and a combination of chromatographic techniques, automated Edman sequencing, and fast atom bombardment mass spectrometry
- Seven out of the eight potential N-glycosylation sites , namely, Asn52, Asn56, Asn208, Asn251, Asn298, Asn372, and Asn489 , turned out to be glycosylated, and the potential glycosylation site at Asn14 , being close to the N-terminus, is not used
- The carbohydrate microheterogeneity on three of the glycosylation sites was studied in more detail by high-pH anion-exchange chromatographic profiling and 500 MHz1H-NMR spectroscopy
- Glycosylation site Asn489 contains mainly di- and tri-charged oligosaccharides which comprise, among others, the GalNAc4 S (beta1-4)GlcNAc terminal sequence
- Only glycosylation site Asn251 bears oligomannose-type carbohydrate chains ranging from Man5GlcNAc2to Man8GlcNAc2, in addition to a small amount of complex-type structures
- Profiling of the carbohydrate moieties of Asn208 indicates a large heterogeneity, similar to that established for native human Tamm-Horsfall glycoprotein , namely, multiply charged complex-type carbohydrate structures , terminated by sulfate groups, sialic acid residues, and/or the Sda-determinant