S. N. Senchenkova

New structures of the O-specific polysaccharides of bacteria of the genus Proteus. 1. Phosphate-containing polysaccharides.

The O-specific polysaccharide chains (O-antigens) of the lipopolysaccharides of five Proteus strains, P. vulgaris O17, P. mirabilis O16 and O33, and P. penneri 31 and 103, were found to contain phosphate groups that link the non sugar components, e.g., ethanolamine and ribitol. The polysaccharides of P. mirabilis O16 and P. penneri 103 include ribitol phosphate in the main chain and thus resemble ribitol teichoic acids of Gram-positive bacteria. The structures of the polysaccharides were elucidated using NMR spectroscopy, including two-dimensional 1H, 1H correlation spectroscopy (COSY and TOCSY), nuclear Overhauser effect spectroscopy (NOESY or ROESY), and H-detected 1H, 13C and 1H, 31P heteronuclear multiple-quantum coherence spectroscopy (HMQC), along with chemical methods. The structures determined are unique among the bacterial polysaccharides and, together with the data obtained earlier, represent the chemical basic for classification of Proteus strains. Based on structural similarities of the O-specific polysaccharides and serological relationships between the O-antigens, we propose to extend Proteus serogroups O17 and O19 by including P. penneri strains 16 and 31, respectively.

New structures of the o-specific polysaccharides of Proteus. 4. Polysaccharides containing unusual acidic N-acyl derivatives of 4-amino-4,6-dideoxy-D-glucose

The structures of the O-polysaccharides of the lipopolysaccharides of Proteus mirabilis O7 and O49 were determined by chemical methods, mass spectrometry, including MS/MS, and NMR spectroscopy, including experiments run in an H2O/D2O mixture to reveal correlations for NH protons. The O-polysaccharides were found to contain N-carboxyacetyl (malonyl) and N-(3-carboxypropanoyl) (succinyl) derivatives of 4-amino-4,6-dideoxyglucose (4-amino-4-deoxyquinovose, Qui4N), respectively. The behavior of Qui4N derivatives with the dicarboxylic acids under conditions of acid hydrolysis and methanolysis was studied using GLC-MS.

Teichuronic and Teichulosonic Acids of Actinomycetes

The subject of the present review is the structural diversity and abundance of cell wall teichuronic and teichulosonic acids of representatives of the order Actinomycetales. Recently found teichulosonic acids are a new class of natural glycopolymers with ald-2-ulosonic acid residues: Kdn (3-deoxy-D-glycero-D-galacto-non-2-ulosonic acid) or di-N-acyl derivatives of Pse (5,7-diamino-3,5,7,9-tetradeoxy-L-glycero-L-manno-non-2-ulosonic or pseudaminic acid) as the obligatory component. The structures of teichuronic and teichulosonic acids are presented. Data are summarized on the occurrence of the glycopolymers of different nature in the cell wall of the studied actinomycetes. The biological role of the glycopolymers and their possible taxonomic implication are discussed. The comprehensive tables given in the Supplement show 13C NMR spectroscopic data of teichuronic and teichulosonic acids obtained by the authors.

D- and L-Aspartic Acids: New Non-sugar Components of Bacterial Polysaccharides

For the first time in bacterial polysaccharides, residues of D- and L-aspartic acids were identified as N-acyl substituents of 4-amino-4,6-dideoxy-D-glucose in the O-antigens of enterobacteria of the generaProvidencia andProteus.

New structures of the O-specific polysaccharides of Proteus. 2. Polysaccharides containing O-acetyl groups

Structures of five new O-specific polysaccharides of Proteus bacteria were established. Four of them, Proteus penneri 4 (O72), Proteus vulgaris 63/57 (O37), Proteus mirabilis TG 277 (O69), and Proteus penneri 20 (O17), contain O-acetyl groups in non-stoichiometric quantities, and the polysaccharide of P. penneri 1 is structurally related to that of P. penneri 4. The structures were elucidated using NMR spectroscopy, including one dimensional 1H- and 13C-NMR spectroscopy, two-dimensional 1H, 1H correlation (COSY, TOCSY), H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY or ROESY), along with chemical methods. The structural data obtained are useful as the chemical basis for the creation of the classification scheme for Proteus strains.

Identification of a Homopolymer of 5-Acetamidino-7-acetamido- 3,5,7,9-tetradeoxy-D-glycero-D-talo-nonulosonic Acid in the Lipopolysaccharides of Legionella pneumophila Non-1 Serogroups

O-Specific polysaccharides (OPS) were isolated by mild acid hydrolysis of the lipopolysaccharides (LPS) of strainsof Legionella pneumophila serogroups 2-14, as well as strains Lansing 3 and 16453-92 from newly proposed serogroups. TheOPS were studied by 1H- and 13C-NMR spectroscopy, GLC/mass spectrometry, and chemical modifications (mild alkalineO-deacetylation and conversion of the N-acetimidoyl group into the N-acetyl group). All OPS were found to be ahomopolymer of a 5-acetamidino-7-acetamido-3,5,7,9-tetradeoxynonulosonic acid, which in some strains is 8-O-acetylat-ed. In most strains studied, the monosaccharide has the D-glycero-D-talo configuration and is thus the C4 epimer of legion-aminic acid (4-epilegionaminic acid), which has been previously identified as the monomer in the OPS of L. pneumophilaserogroup 1. Poly(4-epilegionaminic acid) occurs as a minor polysaccharide in serogroups 5 (strain Dallas 1) and 13 and isabsent in serogroups 1 and 7. The chemical basis for serological differentiation of L. pneumophila strains is discussed.

Phosphate-containing cell wall polymers of bacilli.

Anionic phosphate-containing cell wall polymers of bacilli are represented by teichoic acids and poly(glycosyl 1-phosphates). Different locations of phosphodiester bonds in the main chain of teichoic acids as well as the nature and combination of the constituent structural elements underlie their structural diversity. Currently, the structures of teichoic acids of bacilli can be classified into three types, viz. poly(polyol phosphates) with glycerol or ribitol as the polyol; poly(glycosylpolyol phosphates), mainly glycerol-containing polymers; and poly(acylglycosylglycerol phosphate), in which the components are covalently linked through glycosidic, phosphodiester, and amide bonds. In addition to teichoic acids, poly(glycosyl 1-phosphates) with mono- and disaccharide residues in the repeating units have been detected in cell walls of several Bacillus subtilis and Bacillus pumilus strains. The known structures of teichoic acids and poly(glycosyl 1-phosphates) of B. subtilis, B. atrophaeus, B. licheniformis, B. pumilus, B. stearothermophilus, B. coagulans, B. cereus as well as oligomers that link the polymers to peptidoglycan are surveyed. The reported data on the structures of phosphate-containing polymers of different strains of B. subtilis suggest heterogeneity of the species and may be of interest for the taxonomy of bacilli to allow differentiation of closely related organisms according to the “structures and composition of cell wall polymers” criterion

Anionic polymers of the cell wall of Bacillus subtilis subsp. subtilis VKM B-501T

Teichoic acid and disaccharide-1-phosphate polymer were identified in the cell walls of Bacillus subtilis subsp. subtilis VKM B-501T. The teichoic acid represents 1,3-poly(glycerol phosphate) 80% substituted by α-D-glucopyranose residues at O-2 of glycerol. The linear repeating unit of disaccharide-1-phosphate polymer contains the residues of β-D-glucopyranose, N-acetyl-α-D-galactosamine, and phosphate and has the following structure: -6)-β-D-Glcp-(1→3)-α-D-GalpNAc-(1-P-. The structures of two anionic polymers were determined by chemical and NMR-spectroscopic methods. The 1H- and 13C-NMR spectral data on disaccharide-1-phosphate polymer are presented for the first time.

New structures of the O-specific polysaccharides of Proteus. 3. Polysaccharides containing non-carbohydrate organic acids.

Four new Proteus O-specific polysaccharides were isolated by mild acid degradation from the lipopolysaccharides of P. penneri 28 (1), P. vulgaris O44 (2), P. mirabilis G1 (O3) (3), and P. myxofaciens (4), and their structures were elucidated using NMR spectroscopy and chemical methods. They were found to contain non-carbohydrate organic acids, including ether-linked lactic acid and amide-linked amino acids, and the following structures of the repeating units were established: →3)-α-L-QuipNAc-(1→3)-α-D-GlcpNAc-(1→6)-α-D-GlcpNAc-(1→ (S)-Lac-(2–3)⌋ (1) →4)-β-D-GlcpA-(1→3)-β-D-GalpNAc-(1→4)-β-D-Glcp-(1→3)-α-D-Galp-(1→4)-β-D-GalpNAc-(1→ L-Ala-(2–6)⌋ (2) →3)-β-D-GalpNAc-(1→6)-β-D-GalpNAc-(1→4)-β-D-GlcpA-(1→ L-Lys-(2–6)-α-D-GalpA-(1→4)⌋ (3) →4)-β-D-GlcpA-(1→6)-α-D-GalpNAc-(1→6)-β-D-GlcpNAc-(1→3)-β-D-GlcpNAc-(1→ (R)-aLys-(2–6)⌋ (4) where (S)-Lac and (R)-aLys stand for (S)-1-carboxyethyl (residue of lactic acid) and Nε-[(R)-1-carboxyethyl]-L-lysine (“alaninolysine”), respectively. The data obtained in this work and earlier serve as the chemical basis for classification of the bacteria Proteus.

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

O-Antigens (O-specific polysaccharides) of Shigella flexneri, a primary cause of shigellosis, are distinguished by a wide diversity of chemical modifications following the oligosaccharide O-unit assembly. The present review is devoted to structural, serological, and genetic aspects of these modifications, including O-acetylation and phosphorylation with phosphoethanolamine that have been identified recently. The modifications confer the host with specific immunodeterminants (O-factors or O-antigen epitopes), which accounts for the antigenic diversity of S. flexneri considered as a virulence factor of the pathogen. Totally, 30 O-antigen variants have been recognized in these bacteria, the corresponding O-factors characterized using specific antibodies, and a significant extension of the serotyping scheme of S. flexneri on this basis is suggested. Multiple genes responsible for the O-antigen modifications and the resultant serotype conversions of S. flexneri have been identified. The genetic mechanisms of the O-antigen diversification by acquisition of mobile genetic elements, including prophages and plasmids, followed occasionally by gene mobilization and inactivation have been revealed. These findings further our understanding of the genetics and antigenicity of S. flexneri and assist control of shigellosis.