Structure of an exocellular polysaccharide produced by Streptococcus thermophilus.
Streptococcus thermophilus strains grown on skimmed milk produced a viscosifying, exocellular, and water-soluble polysaccharide which contains D-glucose, D-galactose, and N-acetyl-D-galactosamine in the ratio of 1:2:1. Methylation analysis identified the glycosidic linkages in the tetrasaccharidic repeating-unit, and Smith degradation and nitrous deamination after N-deacetylation gave the sequence of monosaccharides in the repeating-unit. The anomeric configurations of the sugar residues were determined by oxidation of the peracetylated polysaccharide with chromium trioxide and by 1H- and 13C-n.m.r. spectroscopy. The following structure was assigned to the repeating unit of the polysaccharide,----3)-beta-D-Galp-(1----3)-[alpha-D-Galp-(1----6)]-beta- D- Glcp-(1----3)-alpha-D-GalpNAc-(1----.
Doco
T
T
Laboratoire de Chimie Biologique de l'Université des Sciences et Techniques de Lille Flandres-Artois, Unité Associée au C.N.R.S. No 217, Villeneuve d'Ascq, France.
Wieruszeski
J M
JM
Fournet
B
B
Carcano
D
D
Ramos
P
P
Loones
A
A
D000107:Acetylation; D002240:Carbohydrate Sequence; D055598:Chemical Phenomena; D002621:Chemistry; D002857:Chromium; D017608:Chromium Compounds; D008745:Methylation; D008969:Molecular Sequence Data; D010504:Periodic Acid; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D013291:Streptococcus / Q000378:metabolism
D017608:Chromium Compounds; D011135:Polysaccharides, Bacterial; D002857:Chromium; D010504:Periodic Acid; C028801:chromium trioxide; C009288:metaperiodate