Diversity of O‐linked glycosylation patterns between species

Abstract

Amphibia egg jelly coats are formed by components secreted along the oviduct. These secretion products overlay the oocytes as they pass along the different oviducal portions. Mucin type glycoproteins are the major constituents of the egg jelly coats. In this study, the O-linked carbohydrate chains of the jelly coats surrounding the eggs of Rana ridibunda were released by alkaline borohydride treatment. Fractionation of the mixture of O-linked oligosaccharidealditols was achieved by a combination of chromatographic techniques including gel-permeation chromatography, ion-exchange chromatography and high-performance liquid chromatography using an amino-bonded silica column. The primary structures of these O-glycans were determined by one-dimensional and two-dimensional 1 H-NMR spectroscopy and matrix-assisted laser-desorption-ionization-time-of flight mass spectrometry. 25 oligosaccharide structures, possessing a core consisting of Gal(b1±3)GalNAc-ol with or without branching through a GlcNAc residue linked (b1±6) to the GalNAc residue (core type 2 or core type 1, respectively) are described. The most representative antennae are:Gal(b1-3)GalNAc(a1-4)Gal(b1-4)Gal and GlcA(b1-3)Gal(b1-3)GalNAc. These results confirm the species-specific O-glycosylation of Amphibia oviducal mucins. The significance of this observation should be linked to a symbiotic role of carbohydrates involved in host±parasite interactions.Keywords: Amphibia; mucins; Rana ridibunda; NMR; carbohydrates.A characteristic feature of amphibia eggs is the presence of a water-insoluble gelatinous matrix, termed the jelly coat, surrounding the egg. Jelly coat layers are synthesized by specific regions of the oviduct and are sequentially deposited as the egg is transported toward the cloaca. Interest in these oviductally derived investments has centered on their obligatory participation in the early events of fertilization. The jelly coats are the first barrier for fertilizing sperm that must be passed through before reaching the egg plasma membrane. Thus, the jelly coats play a key role in the process of fertilization by facilitating adherence of the spermatozoa to the egg surface and by acting to block polyspermy [1±4].Mucin type glycoproteins have been shown to be the major components of this coat and implicated in important roles in fertilization. Of particular interest are several proposals suggesting the role of sugar chains as sperm receptors, due to the action of glycosidases or glycosyltransferases. Previous structural studies have demonstrated a remarkable species specificity in carbohydrate chains attached to the proteic axis of the oviducal mucins [5±11]. Consequently, these carbohydrate chains represent new phenotypic markers of amphibia species, and from a biological point of view, could be involved in species-specific gamete-recognition or in specific host±parasite interaction [12].Moreover, these structural analyses have led to the definition of several new glycosyltransferase activities reponsible for the structural species specificity. Acc...

The Diversity of O-Linked Glycans Expressed during Drosophila melanogaster Development Reflects Stage- and Tissue-specific Requirements for Cell Signaling

“…For instance, we detected GlcA in Drosophila as an internal residue, capped with HexNAc, whereas sialic acid is almost exclusively a nonreducing terminal residue in vertebrate oligosaccharides. The only occurrence of vertebrate sialic acid residues in other than terminal positions is when the sialic acid is covered in ␣2-8 linkage by another sialic acid or by a polymer of sialic acid (42,78,79). We did not detect analogous GlcA-GlcA dimers or extended GlcA homopolymers in our O-linked preparations.…”

Mass Spectrometry-Based Glycoproteomic Approach Involving Lysine Derivatization for Structural Characterization of Recombinant Human Erythropoietin

“…Thus, after the N -glycans release, only the O -glycopeptides remained in the peptide mixture, giving the opportunity to be easily detected by performing extracted ion chromatograms within the mass window of 1 Da for the m / z values 204 (HexNAc + ), 292 (Neu5Ac + ), 366 (Hex-HexNAc + ), and 657, (NeuAc-Hex-HexNAc + ), respectively, characteristic for O -glycans. The lack of an O -glycosidase for detachment of all glycans linked to Ser/Thr and severe conditions for the classical chemical cleavage by β-elimination in basic environment causing peptide degradation ,, usually make the investigation of O -glycosylation more difficult, , and frequently, incomplete data are obtained. As an alternative, the direct MS analysis of O -linked peptides is a more efficient analytical tool.…”

SOACS index: an easy NMR-based query for glycan retrieval

“…Calculation of SOACS index for N-Glycans is essentially the same than for O-glycans. However, the core 3, 33 9,001 13,395 rd A-8 25 18,952 23,347 rc C6 34 28,242 32,628 rc D1 34 9,001 13,395 ra 100-G 33 18,963 23,355 ra 100-M 33 28,339 32,667 xt 5A 35 9,002 13,395 rtb 12 29 18,994 23,393 bv 3 36 28,626 33,027 rt 300-5 17 9,022 13,411 rd A-4B 25 19,169 23,564 rd A-19B 25 28,827 33,160 rd A-5 25 9,022 13,411 ra 100-H 33 19,244 23,615 rr 100-12 30 28,879 33,234 rtb 6 29 9,094 13,483 rd A12-B 25 19,276 23,645 rr 400-II-4 30 28,895 33,246 ra 50-5 33 9,201 13,596 ra 100-F 33 19,276 23,645 rr 400-II-3 30 28,976 33,340 rt 200-7 17 9,203 13,592 rt 4 28 19,286 23,675 bv 4 36 29,231 33,231 rd N-4 25 9,413 13,821 ra 100-D 33 19,320 23,670 rr 100-11 30 29,288 33,651 rp N-2 32 9,413 13,821 ra 50-10 33 19,374 23,728 bv 5 36 29,429 33,662 rd N-3 29 9,820 14,210 rr 100-7 30 19,381 23,741 ra 100-L 33 29,508 33,732 ra FNII-3 33 9,820 14,210 rd A-7C 25 19,393 23,785 rt 7 28 29,592 33,924 rtb 4 29 10 6-linked b-Manp (residue 3, Fig. S3) H-1 (H1 Man3) value is not computed because its exact reading is rendered hazardous by the proximity of residual HOD signal at 300 K ($4.76 ppm) and is invisible in most cases.…”