R- and S-Pyruvate-Containing Polysaccharide from the Cell Wall of Rathayibacter sp. VKM Ac-2927

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Maksim S. Kokoulin¹, Natalia V. Potekhina^2,a*, Elena M. Tul’skaya², Yury V. Ospennikov³, Lyudmila I. Evtushenko³

¹Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022 Vladivostok, Russia

²Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia

³All-Russian Collection of Microorganisms (VKM), Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia

^* To whom correspondence should be addressed.

Received: March 12, 2025; Revised: April 23, 2025; Accepted: April 23, 2025

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The structures of two cell wall glycopolymers from the strain Rathayibacter sp. VKM Ac-2927 (family Microbacteriaceae, class Actinomycetes), isolated from the leaves of a linden affected by leaf miner, were established using chemical and NMR spectroscopy methods. The first polymer, rhamnomannan, is a heterogeneous chain polymer composed of regularly alternating α-D-rhamnose and α-D-mannose residues linked by (1→3)- and (1→2)-glycosidic bonds and contains a minor amount of lateral β-D-xylopyranose residues (structure is presented in the text). The second polymer, acetalized with R- and S-pyruvic acid, consists of branched tetrasaccharide units, →3)-α-D-Galp4,6-(R-Pyr)-(1→3)-β-D-Glcp-(1→6)-[β-D-Galp3,4-(S-Pyr)-(1→4)]-α-D-Manp-(1→. Structure of this polysaccharide is new for the representatives of the genus Rathayibacter and prokaryotes in general. The results of present study indicate structural diversity of microbial glycopolymers and are consistent with the previously obtained data on specificity of their composition for the species of the Rathayibacter genus.

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KEY WORDS: Rathayibacter, cell wall glycopolymers, polysaccharide, rhamnomannan, pyruvate

DOI: 10.1134/S0006297925600759

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