D-Rhamnan and Pyruvate-Containing Teichuronic Acid from the Cell Wall of Rathayibacter sp. VKM Ac-2759.

Rathayibacter sp. VKM Ac-2759 (family Microbacteriaceae, class Actinobacteria) contains two glycopolymers in the cell wall. The main chain of rhamnan, glycopolymer 1, is built from the repeating tetrasaccharide units carrying terminal arabinofuranose residues at the non-reducing end, →3)-α-[α-D-Araf-(1→2)]-D-Rhap-(1→2)-α-D-Rhap-(1→3)-α-D-Rhap-(1→2)-α-D-Rhap-(1→. Similar to other described Rathayibacter species, rhamnose in the neutral glycopolymer of the VKM Ac-2759 strain is present in the D-configuration. Acetalated with pyruvic acid teichuronic acid, glycopolymer 2, is composed of the repeating tetrasaccharide units, →4)-ß-D-GlcpA-(1→4)-ß-D-Galp-(1→4)-ß-D-Glcp-(1→3)-ß-[4,6-S-Pyr]-D-Manp-(1→. Glycopolymers 1 and 2 were identified in prokaryotic microorganisms for the first time and their structures were established by chemical analysis and NMR spectroscopy. The obtained data can be used in taxonomic research, as well as for elucidating the mechanisms of plant colonization and infection by bacteria of the Rathayibacter genus.

D-rhamnan and teichuronic acid from the cell wall of Rathayibacter caricis VKM Ac-1799T.

The cell wall of Rathayibacter caricis VKM Ac-1799T (family Microbacteriaceae, class Actinobacteria) was found to contain both neutral and acidic glycopolymers. The first one is D-rhamnopyranan with main chain →2)-α-D-Rhap-(1 â†’ 3)-α-D-Rhap-(1→, where a part of 2-substituted residues bears as a side-chain at position 3 α-D-Manp residues or disaccharides α-D-Araf-(1→2)-α-D-Manp-(1 â†’ . The second polymer is a teichuronic acid with a branched repeating units composed of seven monosaccharides →4)-α-[ß-D-Manp-(1 â†’ 3)]-D-Glcp-(1 â†’ 4)-ß-D-GlcpA-(1 â†’ 2)-ß-[4,6Pyr]-D-Manp-(1 â†’ 4)-ß-L-Rhap-(1 â†’ 4)-ß-D-Glcp-(1 â†’ 4)-ß-D-Glcp-(1 â†’ . The structures of the polymers were determined by chemical and NMR spectroscopic methods.