title: Donor specificity in the glycosylation of Tamm-Horsfall glycoprotein: conservation of the Sda determinant in pairs of twins.
abstract: The content of the Sd(a) determinant in urinary human Tamm-Horsfall glycoprotein (THp) has been reported to be donor-specific. This feature was further addressed by investigating THp from genetically identical individuals. To this end, THp was isolated from the urine of two monozygotic pairs of twins (A and B). The four samples (THp A1, A2, B1, and B2) were subjected to endo-beta-galactosidase from Bacteroides fragilis leading to the liberation of the Neu5Ac(alpha2-3)Gal (beta1-4)GlcNAc(beta1-3)Gal and Neu5Ac(alpha2-3)[GalNAc(beta1-4)] Gal(beta1-4)GlcNAc(beta1-3)Gal (Sd(a) epitope) motifs, both located at the nonreducing termini of complex type N-glycans. The isolated mixtures of oligosaccharides were analyzed for the absolute and relative amounts of the two oligosaccharides. The obtained data clearly indicate that in THp A1 and A2, and in THp B1 and B2, the molar ratios of the tetra- and Sd(a) pentasaccharide are identical for a pair of twins. This conservation of molar ratios points to an identical relative expression of beta-1,4-N-acetylgalactosaminyltransferase activity involved in the biosynthesis of the Sd(a) determinant. Apparently, the degree of conversion of the tetrasaccharidic Sd(a) precursor into the final pentasaccharidic Sd(a) form can be considered to result from a very closely related pattern of glycosylation for genetically homogeneous individuals.
authors.affiliation: Bijvoet Center, Department of Bio-Organic Chemistry, Section of Glycoscience and Biocatalysis, Utrecht University, Padualaan 8, NL-3584 CH Utrecht, The Netherlands.
authors.forename: Philippe F
authors.initials: PF
authors.lastname: Rohfritsch
authors.forename: Meike
authors.initials: M
authors.lastname: Rinnbauer
authors.forename: Johannes F G
authors.initials: JF
authors.lastname: Vliegenthart
authors.forename: Johannis P
authors.initials: JP
authors.lastname: Kamerling
mesh_terms: D020816:Amino Acid Motifs; D002851:Chromatography, High Pressure Liquid; D017124:Conserved Sequence; D005260:Female; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D008297:Male; D009088:Mucoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000652:urine; D011499:Protein Processing, Post-Translational; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D058949:Uromodulin
chemical_list: D009088:Mucoproteins; C548612:UMOD protein, human; D058949:Uromodulin; D006026:Glycoside Hydrolases; C026093:keratan-sulfate endo-1,4-beta-galactosidase