Complete NMR structural elucidation of the capsular polysaccharide adjuvant from Klebsiella I-714.
The capsular polysaccharide (CPS) produced by the non-pathogenic Klebsiella strain I-714, selected for its immunomodulating activity, has been purified and almost completely detoxified in a previous study [Adam, O., Vercellone, A., Paul, F., Monsan, P. F. & Puzo, G. (1995) Anal. Biochem. 225, 321-327]. The present report concerns the structural elucidation of this CPS by several one-dimensional and two-dimensional 1H-NMR and 13C-NMR experiments performed on the native molecule. It was found to be a high molecular-mass branched polymer constituted by a hexasaccharide repeating unit of following structure: 4)-alpha-L-Rhap-(1-->3)-beta-D-Galp-(1-->2)-alpha-L-Rhap-(1- ->4)-beta-D- GlcpA-(1-->3)-¿alpha-L-Rhap-(1-->2)-¿-alpha-D-Galp-(1. The presence of two glycosidic substitutions on the Galp residue resulted in a strong overlapping of its proton signals, preventing direct assignment of both proton and carbon resonances. However, assignment could be achieved using the two-bond and three-bond 1H-13C heteronuclear coupling observed in the 1H-13C heteronuclear multiple-bond correlation (HMBC) spectrum.
Institut de Pharmacologie et de Biologie Structurale du CNRS, Toulouse, France.
O
O
Adam
M
M
Riviére
A
A
Vercellone
P F
PF
Monsan
G
G
Puzo
D000276:Adjuvants, Immunologic / Q000737:chemistry* / Q000302:isolation & purification; D002240:Carbohydrate Sequence; D006031:Glycosylation; D007709:Klebsiella / Q000737:chemistry* / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000276:immunology* / Q000302:isolation & purification
D000276:Adjuvants, Immunologic; D011135:Polysaccharides, Bacterial