Structural Studies on N-Acetylmannosaminuronic Acid-Containing and Glucuronic Acid-Containing Teichuronic Acids in the Cell Wall of Bacillus megaterium AHU 1375

Structural studies were carried out on two kinds of teichuronic acid-glycopeptide complexes (designated as TU-GP-I and TU-GP-II) isolated from lysozyme digest of N-acetylated cell walls of Bacillus megaterium AHU 1375 by ion-exchange chro-matography and gel chromatography. TU-GP-I, accounting for about 25% of the cell walls, contained N-acetylmannosaminuronic acid, ,N-acetylglucosamine, glucose, galactose, glycerol, and phosphorus in an approximate molar ratio of 1 : 1 : 2 : 1 : 0.5 :0.5, together with small amounts of glycopeptide components. TU-GP-II, accounting for about 9% of the cell walls, contained glucuronic acid, glucose, and fucose in a molar ratio of about 2 : 1.5 : 1, together with small amounts of glycopeptide components. The results of analyses involving Smith degradation, chromium oxidation, methylation, acetolysis, and 1H-NMR measurement led to the conclusion that the polysaccharide chain of TU-GP-I comprised repeating units, →6)Glc(αl→3)-ManNAcUA(β1→4)[Gal(α1→3)][Glc(β1→6)]GlcNAc(β1→. About half of the repeating units were substituted by glycerophosphoryl residues at C-6 of the β-glucosyl residues linked to the N-acetylglucosamine residues. By means of a similar procedure, the polysaccharide chain of TU-GP-II was shown to comprise repeating units, ⇒4)GlcUA(al⇒3)GlcUA(al⇒3)Glc(al⇒3)Fuc(al⇒, of which about half were substituted by a-glucosyl residues at C-3 of the 4-substituted glucuronosyl residues.