Structural analysis of the specific capsular polysaccharide of Rhodococcus equi serotype 2.
The specific capsular polysaccharide produced by Rhodococcus equi serotype 2 is a high-molecular-weight acidic polymer composed of D-glucose, D-mannose, D-glucuronic acid and 3-O-[(S)-1-carboxyethyl]-L-rhamnose in equimolar proportions. Structural analysis, employing a combination of chemical and n.m.r. techniques, established that the polysaccharide is composed of linear repeating tetrasaccharide units. (formula; see text) in which the beta-D-mannose residues carry O-acetyl groups at O-2 and O-3 to the extent of 1.7 mol equivalents. Unequivocal determination of the absolute chirality of the 3-O-[(S)-1-carboxyethyl]-alpha-L-rhamnose residues was achieved by chemical correlation with an authentic synthetic sample. The 1H and 13C-n.m.r. resonances of the native and O-deacetylated serotype 2 polysaccharides were fully assigned by homo- and heteronuclear chemical-shift correlation methods.
Severn
W B
WB
Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
Richards
J C
JC
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012240:Rhodococcus / Q000032:analysis* / Q000145:classification; D012703:Serotyping
D011135:Polysaccharides, Bacterial