Bacteriophage degradation of the capsular polysaccharide of Klebisella K24 and determination of the position of the O-acetyl group

✍ Scribed by Geoffrey Annison; Guy G.S. Dutton; Prabir K. Mandal

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 434 KB
• Volume: 177
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(88)85065-1

✦ Synopsis

The elucidation of the structure of the capsular polysaccharides from pathogenic bacteria has attracted the attention of research workers for many years. The main motivation for this work has been the possibility of utilising capsular polysaccharides (CPS) or derived structures as vaccines. In some cases non-carbohydrate substituents, and particularly 0-acetyl groups, form part of the ~mmunodominant structures of bacterial polysaccharides'. Thus, the location of these substituents is an important aspect of polyaccharide structural determination.

In a previous study*, it was established that the repeating unit structure of Kfebsielia K24 CPS is:

-2)cx-D-GlcA-( 1+3)-o-D-Man-( l--+2)-cu-D-Man-(l-3)-B-n-Glc-(I-* 4

P-D-Man in addition, 0-acetyl groups were found to be present and were tentatively assigned to one of the mannose units.

We now report the 0-acetyl group to be located on C-6 of the 2-linked (Y-Dmannose residue. This was determined by 'H-and r3C-n.m.r. spectroscopic analysis of the intact native and 0-deacetylated K24 capsular polysaccharide and of an oiigosaccharide (Pl), generated by a bacteriophage glycanase, in conjunction with chemical and methyl&ion analyses of Pl. KZebsiella K24 CPS was depolymerised using a crude bacteriophage preparation. Dialysis of the depolymerised material and gel filtration of the dialysate yielded Pl (7.5% yield) and a higher oligomer (45% yield). Reduction and preparation of the peracetylated aldononitrile derivatives3 of Pl showed glucose at the *On leave from Rampurhat College, West Bengal, India.