High selectivity in the partial degradation of an extracellular polysaccharide of Rhizobium japonicum with liquid hydrogen fluoride: A n.m.r.-spectroscopic study
✍ Scribed by Andrew J. Mort; Jean-Pierre Utille; Giangiacomo Torri; Arthur S. Perlin
- Book ID
- 102991015
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 583 KB
- Volume
- 121
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
The extracellular polysaccharide of Rhizobium japonicum consistb of Dglucosyl, D-mannosyl, D-galactosyl, 4-O-acetyl-D-g&ctosyluronic acid residues, and 4-0-methyl-I)-galactosyl groups. When subjected to lreatment with liquid hydrogen fluoride at -4o", the polymer affords a pentasaccharidr (4) and a higher homolog (2) of it, rcprcscntativc of both the major rcpcating scqucncc and minor structural variants that differ in degrees of 0-methylation and 0acetylation. The structures of 2 and 4, and hence that of the polymer, were determined primarily by 'H-and '%Sn.m.r. spectroscopy and methylation analysis. Another product of the degradation reaction, both at -40 and -23", was the trisaccharide O-/~-D-gluco-pyranOsyl-(~~3)-~-(4-~-acely~-~-D-galactopyranosyluronic acid)-(l-+3)-D-mannose which, under controlled conditions, was isolated as the ru-glucosyl fluoride. The results show that, in the Rhizobium polysaccharide, the a-D-glUCopyran0Syl
residue is by far the most highly prone to hydrofluorinolysis. followed in susceptibility by the a-D-mannOpyranOSyl residue and u-D-galactopyranosyl group.