ANALYSIS OF A NOVEL LINKAGE UNIT OF O-LINKED CARBOHYDRATES FROM THE CRYSTALLINE SURFACE-LAYER GLYCOPROTEIN OF CLOSTRIDIUM-THERMOHYDROSULFURICUM S102-70

The surface layer glycoprotein of Clostridium thermohydrosulfuricum S102-70 was shown to contain a new type of glycan chain. Different from all known eubacterial glycoproteins, the saccharide moiety consists only of six sugar residues without any repeat sequences. Proteolytic digestion of purified S-layer glycoprotein resulted in isolation of several glycopeptide fractions. These are composed of the same hexasaccharide portion but are linked to oligopeptides of different length. One of them contains only a single amino acid. As concluded from chemical analyses and proton and carbon nuclear magnetic resonance spectroscopy of this preparation, the hexasaccharide moiety is linked via a novel O-glycosidic linkage. This is a beta-D-glucose residue linked to the phenolic hydroxyl group of tyrosine in intact S-layer glycoprotein.