Structural analysis of 20 oligosaccharide‐alditols released from the jelly coat ofRana palustriseggs by reductive β‐elimination

Abstract

The eggs of amphibians are surrounded by three to eight layers of jelly coats. This extracellular matrix is mainly composed of hydrated mucin-type glycoproteins. These highly glycosylated molecules are synthesized by oviduct and play an important role in the fertilization process.Recent structural analyses have shown the strict species-specificity of the O-linked oligosaccharides which constitute 60±70% of these oviducal mucins. Consequently, these carbohydrate chains represent new phenotypic markers, and from a biological point of view, can influence parasite tropism or can be involved in species-specific interaction of gametes.The primary structure of 20 oligosaccharide-alditols, released by alkali/borohydride treatment from the mucin of Rana palustris egg jelly coats, was established by 1 H and 13 C-NMR analysis. Thirteen of these components possess new structures and the polymerization of the sequence Gal(b1±3)GalNAc(a1±4) characterizes the species-specificity of R. palustris.

Sequential two-step multienzyme synthesis of tumor-associated sialyl T-antigens and derivatives

“…2 α2–3-Linked sialyl type 3 glycans (Siaα2–3Galβ1–3GalNAcαOR) have been found in glycoproteins. 3 Sialyl core 1 structure attached to a serine or a threonine residue on peptides or proteins is also called sialyl T-antigen (sialyl Thomsen-Friedenreich antigen or sialyl TF antigen, Siaα2–3Galβ1–3GalNAcα1- O -Ser/Thr). It has been found at an elevated level in O -linked glycoproteins such as mucins in certain cancers including breast cancer.…”

Diversity of O‐linked glycosylation patterns between species

“…7 and Table 7), owing to the magnitude of the observed vicinal couplings ( J 1,2 = 3.8 Hz; J 2,3 = 8.0 Hz; J 3,4 = 3.8 Hz and J 4,5 = 1 Hz). The downfield shift of the Gal V H‐4 resonance (Δδ = + 0.085), as compared to 100‐9 , is identical to that observed between Gal(β1–3)GalNAc‐ol and GalNAc(α1–4)Gal(β1–3)GalNAc‐ol [7]. The additional presence of sulfate ( 400‐II‐6 ) and fucose ( 200‐I‐8 ) was deduced from the observations already reported above for compounds 200‐I‐2 and 200‐I‐7 .…”

“…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].…”

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.…”