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Capsular Polysaccharide of the Bacterium Azospirillum lipoferum Sp59b: Structure and Antigenic Specificity

O. N. Smol’kina1*, V. V. Kachala2, Yu. P. Fedonenko1, G. L. Burygin1, E. L. Zdorovenko2, L. Yu. Matora1, S. A. Konnova1,3, and V. V. Ignatov1

1Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, pr. Entuziastov 13, 410049 Saratov, Russia; fax: (8452) 970-383; E-mail: room308@ibppm.sgu.ru

2Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky pr. 47, 119991 Moscow, Russia; E-mail: evelina@ioc.ac.ru

3Saratov State University, ul. Astrakhanskaya 83, 410012 Saratov, Russia; E-mail: konnovasa@info.sgu.ru

* To whom correspondence should be addressed.

Received May 7, 2009; Revision received June 16, 2009
Antigenic differences were revealed between the cell wall outer membrane lipopolysaccharides and the capsular high molecular weight bioglycans for a typical strain of the nitrogen-fixing rhizobacterium Azospirillum lipoferum Sp59b using antibodies prepared against the homologous lipopolysaccharide and lipopolysaccharide-protein complex. From the capsular lipopolysaccharide-protein and polysaccharide-lipid complexes of A. lipoferum Sp59b, polysaccharides were isolated and their structure was for the first time established in Azospirillum by monosaccharide analysis which included determination of the absolute configurations, methylation, O-deacetylation, and one- and two-dimensional NMR spectroscopy. The polysaccharides of the capsular complexes were shown to have identical structure of the branched tetrasaccharide repeating unit, which differs from the structure of the O-specific polysaccharide within the outer membrane lipopolysaccharide of this strain.
KEY WORDS: Azospirillum, capsular antigens, polysaccharide structure

DOI: 10.1134/S000629791005010X