ИСТИНА

Glycoconjugates that contain 3-deoxy-D-glycero-D-galacto-non-2-ulosonic acid (Kdn) are widespread in animals, including vertebrates and higher invertebrates. Kdn residues typically occupy the distal end of glycan chains and, as a result, are suitable for interaction with other cells and environmental agents. About 15 years ago, so called Kdn-teichulosonic acids (Kdn-TULA), a mandatory component of which is Kdn, were found in the cell walls of phytopathogenic streptomycetes. We found new Kdn-TULA in the cell walls of various actinomycetes (Streptomyces, Arthrobacter, Brevibacterium, Promicromonospora), which differ in morphology and habitat. Their common structural feature is a backbone composed of residues of α-Kdnp and a hexose or GlcNAc. In the cell walls of all actinomycetes studied, the Kdn-TULA are accompanied by various other glycopolymers, viz. teichoic and teichuronic acids, poly(glycosyl 1-phosphates), and neutral polysaccharides. Being polyanionic polymers, the Kdn-TULA can bind cations, impart negative charge to the cell surface, control the autolysin activity, and are involved in the cell communication within the microbial community and the environment, including higher organisms.