Structure and gene cluster of the O-polysaccharide of Yersinia rohdei H274-36/78.

A branched O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Yersinia rohdei H274-36/78 and found to contain d-rhamnose, d-mannose, and 3,6-dideoxy-4-C-[(S)-1-hydroxyethyl]-d-xylo-hexose called yersiniose A (Yer). Partial acid hydrolysis of the O-polysaccharide eliminated Yer residues to give a modified linear polysaccharide. Studies by sugar analysis and 1H and 13C NMR spectroscopy, including computational NMR analysis, enabled structure elucidation of a hexasaccharide repeating unit of the O-polysaccharide having two Yer residues attached as monosaccharide side chains. The O-antigen gene cluster of Y. rohdei H274-36/78 located between JUMPStart and galF genes contained putative genes for synthesis of precursors of two O-antigen constituents, GDP-d-Man and GDP-d-Rha, whereas genes responsible for synthesis of CDP-Yer were within the chromosome outside the O-antigen gene cluster. Glycosyltransferase genes and ABC 2 transporter genes were present in the O-antigen gene cluster, and hence the structure established is consistent with the polysaccharide synthesis gene content of the genome.

Erratum to: "Structural Relationships Between Genetically Closely Related O-Antigens of Escherichia coli and Shigella spp." [Biochemistry (Moscow), 81, 600 (2016)].

This corrects the article DOI: 10.1134/S0006297916060067.

Structure and gene cluster of a tyvelose-containing O-polysaccharide of an entomopathogenic bacterium Yersinia entomophaga MH96T related to Yersinia pseudotuberculosis.

An O-polysaccharide was isolated from the lipopolysaccharide of an entomopathogenic bacterium Yersinia entomophaga MH96T by mild acid hydrolysis and studied by 2D NMR spectroscopy. The following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: where Tyv indicates 3,6-dideoxy-d-arabino-hexose (tyvelose). The structure established is consistent with the gene content of the O-antigen gene cluster. The O-polysaccharide structure and gene cluster of Y. entomophaga are related to those of some Y. pseudotuberculosis serotypes.

Structural Relationships Between Genetically Closely Related O-Antigens of Escherichia coli and Shigella spp.

Gene clusters for biosynthesis of 24 of 34 basic O-antigen forms of Shigella spp. are identical or similar to those of the genetically closely related bacterium Escherichia coli. For 18 of these relatedness was confirmed chemically by elucidation of the O-antigen (O-polysaccharide) structures. In this work, structures of the six remaining O-antigens of E. coli O32, O53, O79, O105, O183 (all related to S. boydii serotypes), and O38 (related to S. dysenteriae type 8) were established using (1)H and (13)C NMR spectroscopy. They were found to be identical to the Shigella counterparts, except for the O32- and O38-polysaccharides, which differ in the presence of O-acetyl groups. The structure of the E. coli O105-related O-polysaccharide of S. boydii type 11 proposed earlier is revised. The contents of the O-antigen gene clusters of the related strains of E. coli and Shigella spp. and different mechanisms of O-antigen diversification in these bacteria are discussed in view of the O-polysaccharide structures established. These data illustrate the value of the O-antigen chemistry and genetics for elucidation of evolutionary relationships of bacteria.

Synthetic neoglycoconjugates of cell-surface phosphoglycans of Leishmania as potential anti-parasite carbohydrate vaccines.

Leishmania are a genus of sandfly-transmitted protozoan parasites that cause a spectrum of debilitating and often fatal diseases in humans throughout the tropics and subtropics. During the parasite life cycle, Leishmania survive and proliferate in highly hostile environments. Their survival strategies involve the formation of an elaborate and dense cell-surface glycocalyx composed of diverse stage-specific glycoconjugates that form a protective barrier. Phosphoglycans constitute the variable structural and functional domain of major cell-surface lipophosphoglycan and secreted proteophosphoglycans. In this paper, we discuss structural aspects of various phosphoglycans from Leishmania with the major emphasis on the chemical preparation of neoglycoconjugates (neoglycoproteins and neoglycolipids) based on Leishmania lipophosphoglycan structures as well as the immunological evaluation for some of them as potential anti-leishmaniasis vaccines.

[Synthesis of alpha-D-xylopyranosyl phosphate].

Synthesis of alpha-D-xylopyranosyl phosphate is carried out by a modified MacDonald method.

[A synthesis of dolichyl fluorophosphate]. / Sintez dolikholftorfosfata.

An improved method for the synthesis of dolichyl H-phosphonate was developed using 2-chloro-4H-1,3,2-benzodioxaphosphorin-4-one (salicyl chlorophosphite) as a reagent. Dolichyl phosphorofluoridate was for the first time synthesized from dolichyl H-phosphonate by its treatment with chlorotrimethylsilane, oxidation with iodine, and subsequent interaction with fluoride ion in pyridine.

[Synthesis of dolicyl- and polyprenyl sulfates]. / Sintez dolikhil- i poliprenilsul'fatov.

Dolichyl and polyprenyl sulfates were synthesized as analogues of dolichyl and polyprenyl phosphates by the interaction of dolichols and polyprenols with the pyridine-sulfuric anhydride complex.

Dolichyl sulphate and H-phosphonate: enzymatic reactions with activated sugars.

Two phosphate-modified analogues of dolichyl phosphate were evaluated as substrates or inhibitors of the reactions catalyzed by mammalian microsomal enzymes. Dolichyl H-phosphonate could serve as an efficient acceptor for mannosyl and glucosyl transfer. The reaction products were chromatographically different from those formed from dolichyl phosphate. Lower activity of the H-phosphonate was observed for the reaction of N-acetylglucosaminyl phosphate transfer from UDP-GlcNAc. Dolichyl sulphate was shown not to serve as a substrate for the transfer of mannosyl (from GDP-Man), glucosyl (from UDP-Glc) or N-acetylglucosaminyl phosphate (from UDP-GlcNAc) residues in the presence of rat liver microsomes. Weak inhibitory properties of this analogue were demonstrated.

Fucosylation of synthetic oligosaccharides--plant xyloglucan fragments--by mammalian and amphibian fucosyltransferases.

Liver and oviduct of frogs Rana temporaria and Xenopus laevis were shown to possess the activity of beta-galactoside alpha 1-2-fucosyltransferase. Extracts of these tissues as well as porcine and rat submaxillary gland homogenates catalyze the fucosylation of synthetic plant xyloglucan fragments, the disaccharide D-Gal(beta 1-2)D-Xyl and the tetrasaccharide D-Gal(beta 1-2)D-Xyl(alpha 1-6)D-Glc(beta 1-4)D-Glc; the active preparations can be used for enzymatic synthesis of biologically active oligosaccharides.

[Partial purification of glycosyltransferases participating in the biosynthesis of Salmonella anatum and S. kentucky O-antigens using high performance gel chromatography]. / Chastichnaia ochistka glikoziltransferaz, uchastvuiushchikh v biosinteze O-antigenov Salmonella antatum i S. kentucky s pomoshch'iu vysokoéffektivnoi gel'-khromatografii.

The solubilized glycosyltransferases which catalyse the biosynthesis of Salmonella anatum and S. kentucky O-specific polysaccharides were partially purified by HPLC on Superose 12. Two mannosyl transferases from S. kentucky were separated by gel chromatography; these transferases were found useful for chemical-enzymic synthesis of polyprenylpyrophosphate derivatives of trisaccharides Tal-Man-Gal and Man-Tal-Gal.

[Incorporation of paratose residue into Salmonella O-specific polysaccharides using enzymatic reactions]. / Vvedenie ostatka paratozy v O-spetsificheskie polisakharidy salmonell s pomoshch'iu fermentativnykh reaktsii.

The block mechanism of O-specific polysaccharides biosynthesis was demonstrated for Salmonella nitra (serogroup A) and S. haifa (serogroup B). Due to the moderate specificity of glycosyl transferases from S. nitra, S. typhimurium, S. haifa and S. kentucky (serogroup C3) towards the 3,6-dideoxyhexose structure a paratose residue can be incorporated into the polysaccharide chain instead of an abequose residue, and vice versa.

[Chemico-enzymatic synthesis of branched O-specific polysaccharides of Salmonella serotype C2 and C3]. / Khimiko-fermentativnyi sintez razvetvlennykh O-spetsificheskikh polisakharidov salmonell serogrupp C2 i C3.

The possibility of chemical-enzymatic synthesis of branched polysaccharides was demonstrated with the enzymes from Salmonella newport and S. kentucky using synthetic polyprenyl pyrophosphate oligosaccharides. Formation of polymers with alpha 1-2-, beta 1-2-alpha 1-4- and beta 1-4-linkages between glucose residues in the branch and galactose residues of the main chain was shown.

[Incorporation of abequose residues into O-specific polysaccharides of Salmonella serotypes B, C2 and C3]. / Vvedenie ostatkov abekvozy v O-spetsificheskie polisakharidy salmonell serogrupp B, C2 i C3.

The possibility of chemical-enzymatic synthesis of O-specific polysaccharide and its modified derivatives was demonstrated with a cell envelope preparation from Salmonella typhimurium using synthetic polyprenyl pyrophosphate oligosaccharides and CDP-[14C]Abe. It was shown that during biosynthesis of O-specific polysaccharides from S. newport and S. kentucky abequosylation reaction occurs prior to polymerization of oligosaccharide repeating units.

[Acceptor specificity of mannosyl transferases from Salmonella of serotypes C2 and C3]. / Aktseptornaia spetsifichnost' mannoziltransferaz salmonell serogrupp C2 i C3.

Synthetic mono- and disaccharide derivatives of moraprenyl pyrophosphate were studied as mannose acceptors during the assembly of the repeating unit Rha-Man-Man-Gal of the Salmonella newport (serogroup C2) and S. kentucky (serogroup C3) O-antigens. Mannosyl transferases revealed strict specificity towards the configuration of terminal monosaccharide residue at C1 as well as to the type of linkage between monosaccharide residues in the disaccharide acceptor. The specificity of mannosyl transferases towards the structure of subterminal monosaccharide was not absolute. Alpha-D-Glucose and alpha-D-mannose derivatives were found not to serve as mannosyl residue acceptors, whereas those of alpha-D-talose, alpha-D-fucose, 4-deoxy-D-xylo-hexose and Man (alpha 1-3) glucose were substrates in enzymatic mannosylation with formation of polyprenyl pyrophosphate trisaccharides. These derivatives could serve as substrates for two subsequent enzymatic reactions: rhamnosylation and polymerization of the repeating units, yielding 40-60% of the polysaccharides.