Structure elucidation of NeuAc, NeuGc and Kdn-containing O-glycans released from Triturus alpestris oviductal mucins Characterization of the poly LacdiNAc sequence: HSO3(4)(GalNAcβ1-4GlcNAcβ1-3)1-3GalNAcβ1-4(GlcNAcβ1-3)0-1GlcNAcβ1- 6GalNAc-ol

Eggs from Amphibia are surrounded by several layers of jelly that are needed for proper fertilization. Jelly coat is composed of highly glycosylated mucin-type glycoproteins containing up to 60% of carbohydrates, which display a remarkable species-specificity. This material obtained from Triturus alpestris was submitted to reductive β -elimination and the released oligosaccharide-alditols were further fractionated by HPLC. Structural characterization was performed through a combination of two dimensional 1H-1H and 1H-13C NMR and ESI-MS/MS analysis. Numerous carbohydrate chains are characterized by the presence of the Cad (Sda) determinant, including respectively NeuAc, NeuGc or Kdn as a sialic acid. But the most significant O-glycan sequences which mark the difference between the jelly of T. alpestris and other studies amphibian jellies are polymers of GalNAc(β 1-4)GlcNAc (LacdiNAc) which form part of the following sequence: