The structure of the capsular polysaccharide of Shewanella oneidensis strain MR-4

Capsular polysaccharides were extracted from Sheivanella oneidensis strain MR-4, grown on two different culture media. The polysaccharides were analyzed using H-1 and C-13 NMR spectroscopy, and the following structure of the repeating unit was established: -> 4)-beta-D-Man-(1 -> 4)-beta-Glc-(1 -> 3)-beta-D-GlcNAc-(1 ->alpha-D-Qui4Nacyl-(1 -> 4)-alpha-D-GlcA-(1 -> 3) where the residue of 4-amino-4,6-dideoxy-D-glucose (Qui4N) was substituted with different N-acyl groups depending on the growth media. All monosaccharides are present in the pyranose form. In the PS from cells grown on enriched medium (trypticase soy broth, TSB) aerobically it was N-acylated with 3-hydroxy-3-methylbutyrate (60%) or with 3-hydroxybutyrate (40%), whereas in the PS from cells grown on minimal medium (CDM) aerobically it was acylated mostly with 3-hydroxybutyrate (> 90%). (c) 2005 Elsevier Ltd. All rights reserved.