Carbohydrates and glycoforms of the major egg perivitellins from Pomacea apple snails (Architaenioglossa: Ampullariidae)

ITUARTE, S.; DREON, M.S.; PASQUEVICH, M.Y.; FERNÁNDEZ, P.E.; HERAS, H.

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART B, BIOCHEMISTRY & MOLECULAR BIOLOGY.

ELSEVIER SCIENCE INC

Año: 2010 vol. 157 p. 66 - 72

1096-4959

To better understand how glycans contribute to the multiple roles of perivitellins in embryo development,the carbohydrate moieties and glycoforms of the carotenoglycoproteins ovorubin and scalarin from the eggsof Pomacea canaliculata (Lamarck, 1822) and Pomacea scalaris (d'Orbigny, 1835) were studied. All subunits ofboth proteins are glycosylated and appear to be glycoforms with isoelectric points ranging from ∼5.3 to ∼9.1.Complete deglycosylation reduced subunit heterogeneity to spots of similar molecular weight (∼27 and∼25 kDa in scalarin and ovorubin, respectively) but with varying IP. Serine phosphorylation, present in bothperivitellins, explains part of the isoforms. Glycosylation patterns of scalarin were determined usingbiotinylated lectins, PNGaseF treatment and selective chemical deglycosylation, which revealed the presenceof hybrid and oligomannose N-linked glycans in all subunits. Scalarin has terminal sialic acid residuespossibly resistant to neuraminidase and O-linked residues derived from the T- and Tn antigens. Ovorubindisplayed predominantly the same glycans, though in different amounts. Capillary gas chromatography (GC)showed galactose and mannose as the major monosaccharides followed by GlcNAc and fucose. An interestingfeature was the important amount of sialylated and fucosylated structures found in both perivitellinsdetermined by GC, spectroscopy and lectins. This is the first report of these structures in gastropods otherthan heterobranchs.