Rhamnose-Containing Cell Wall Glycopolymers from Rathayibacter toxicus VKM Ac-1600 and “Rathayibacter tanaceti” VKM Ac-2596

Structures of the cell wall glycopolymers from two representatives of the genus Rathayibacter were investigated using chemical, NMR spectroscopy, and optical methods. The R. toxicus VKM Ac-1600 strain contains two neutral glycopolymers–a linear rhamnomannan →2)-α-D-Rhap-(1→3)-α-D-Manp-(1→ and a branched polysaccharide containing in the repeating unit the residues of D-Manp, D-Glcp, and L-Rhap in the ratios of 2: 4: 1, respectively (the structure is presented in the text). The “Rathayibacter tanaceti” VKM Ac-2596 contains a rhamnomannan that is different from the above-described one by localization of glycosidic bonds on the residues of α-Rhap and α-Manp, i.e. →3)-α-D-Rhap (1→2)-α-D-Manp-(1→. The structures of all identified glycopolymers are described for the first time in actinobacteria. The data obtained make it possible to characterize representatives of the studied actinobacteria more fully and can be used to differentiate Rathayibacter species at the phenotype level.