Tandem exploitation of Helix pomatia glycosyltransferases: facile syntheses of H-antigen-bearing oligosaccharides.

Snails from the family Helicidae produce in their albumen glands a highly branched galactan, which consists almost exclusively of D- and L-galactose. The D-Gal residues are glycosydically beta(1-->6)- or beta(1-->3)-linked, whereas the L-Gal moieties are attached alpha(1-->2). Up until the present time, two beta(1-->6)-D-galactosyl transferases and one alpha(1-->2)-L-galactosyl transferase have been identified in a membrane preparation of these glands.

Fast and efficient synthesis of a novel homologous series of L-fucosylated trisaccharides using the Helix pomatia alpha-(1-->2)-L-galactosyltransferase.

The alpha-(1-->2)-L-galactosyltransferase from the albumen gland of the vineyard snail Helix pomatia exhibits high alpha-(1-->2)-L-fucosyltransferase activity and can be used to transfer L-fucose from GDP-L-fucose to terminal, non-reducing D-galactose residues of an oligosaccharide, thus providing facile access to a range of H-antigen-containing oligosaccharides. The enzymatic glycosylation was applied here on a milligram scale to a series of disaccharide acceptor substrates. Apparently the site of interglycosidic linkage between the terminal and subterminal acceptor sugar units is of little or no consequence.

Galactan biosynthesis in snails: a comparative study of beta-(1--> 6) galactosyltransferases from Helix pomatia and Biomphalaria glabrata.

Adult snails synthesize in their albumen glands a polysaccharide which is composed exclusively of D- or D- and L-galactose (Gal) residues which are interglycosidically linked by 1 --> 3 and 1 --> 6 bonds. It is the only carbohydrate source for embryos and freshly hatched snails. Two galactosyltransferases are described in this study which are most likely involved in the biosynthesis of this polysaccharide.

Amino acid sequence of the D-galactose binding lectin II from the sponge Axinella polypoides (Schmidt) and identification of the carbohydrate binding site in lectin II and related lectin I.

The sponge Axinella polypoides contains several D-galactose binding lectins. One of the main components, lectin I was sequenced earlier, the complete sequence of the other major constituent of saline extracts, lectin II has been determined by amino acid sequencing and mass spectrometry. Both lectins have a homology of 65% to each other and both possess a disulfide loop between positions 4 and 46.

The specificity of an alpha-(1-->2)-L-galactosyltransferase from albumen glands of the snail Helix pomatia.

The specificity of an L-galactosyltransferase (L-Gal-T) from albumen glands of the snail Helix pomatia has been studied. This enzyme transfers L-Gal from GDP-L-Gal to various disaccharides with beta-linked D-Gal in terminal non-reducing position, forming an alpha-(1-->2) linkage. The subterminal residue and the type of interglycosidie linkage proved to be of minor importance.