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 genera Providencia and Proteus.

[The degradation of glycoproteins with lithium borohydride. Isolation and analysis of O-glycopeptides with reduced C-terminal amino acid residue]. / Rasshcheplenie glikoproteinov pod vozdeistviem borgidrida litiia. Vydelenie i analiz o-glikopeptidov s vosstanovlennoi C-kontsevoi aminokisloto i.

By the example of fetuin and a blood-group-specific mucin from porcine stomach, we showed that, under conditions of reductive degradation of glycoproteins with LiBH4-LiOH in 70% aqueous tert-butyl alcohol, the reduction and cleavage of amide bonds occur much faster than the simultaneous beta-elimination of carbohydrate chains O-linked with Ser and Thr residues of the peptide chain. The major degradation products containing the O-linked glycans are the O-glycosylated derivatives of 2-aminopropane-1,3-diol and 2-aminobutane-1,3-diol (the products of reduction of glycosylated Ser and Thr) and the glycopeptides containing 2-4 amino acid residues with reduced C-terminal amino acid. Seventeen homogeneous O-glycopeptides were isolated from the fetuin degradation products by ion-exchange and reversed-phase HPLC. Their structures were determined by MALDI-TOF mass spectrometry and by analyses for amino acids, amino alcohols, and carbohydrates. The application of the reaction for characterization of O-glycans and localization of O-glycosylation sites in O- and N,O-glycoproteins is discussed.

Somatic antigens of pseudomonads: structure of the O-specific polysaccharide of Pseudomonas fluorescens biovar B, strain IMV 247.

The O-specific polysaccharide of Pseudomonas fluorescens biovar B, strain IMV 247, was studied by acid hydrolysis, GLC-MS and 1H and 13C NMR spectroscopy, including 1D and 2D NOE, 2D hybrid TOCSY and ROESY (TORO), and 2D H-detected heteronuclear multiple-bond correlation (HMBC) experiments. The polysaccharide was found to contain L-rhamnose, 3.6-dideoxy-3-[(S)-3-hydroxybutyramido]-D-glucose (D-Qui3NHb), 2-acetamido- 2,4,6-trideoxy-4-[(S)-3-hydroxybutyramido-D-glucose (D-QuiNAc4NHb) and 2-acetamido-2- deoxy-D-galacturonic acid (D-GalNAcA). Partial acid hydrolysis of the polysaccharide resulted in a non-reducing GalNAcA-->QuiNAc4NHb disaccharide with the 3-hydroxybutyryl group glycosylated intramolecularly by the QuiN4N residue. The following structure of the tetrasaccharide repeating unit of the polysaccharide was established:-->4) -alpha-D-GalpNAcA-(1-->3)- alpha-D-QuipNAc4NHb-(1-->2)-beta-D-Quip3NHb-(1-->2)-alpha-L- Rhap(1-->.

Structure of the acid-labile galactosyl phosphate-containing O-antigen of the bacterium Proteus vulgaris OX19 (serogroup O1) used in the Weil-Felix test.

The structure of the O-specific polysaccharide chain of Proteus vulgaris OX19 lipopolysaccharide which determines the O1 specificity of Proteus and is used in the Weil-Felix test for diagnostics of rickettsiosis was established. On the basis of 1H- and 13 C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), it was found that the polysaccharide consists of branched pentasaccharide repeating units containing D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, and 2-acetamido-2,6-dideoxy-D-glucose (QuiNAc, two residues), which are connected to each other via a phosphate group (P): [formula: see text]. The polysaccharide is acid-labile, the glycosyl phosphate linkage being cleaved at pH 4.5 (70 degrees C) to give a phosphorylated pentasaccharide with a galactose residue at the reducing end. Structural analysis of the oligosaccharide and a product of its dephosphorylation with 48% hydrofluoric acid using 1H- and 13C-NMR spectroscopy and electrospray ionization mass spectrometry confirmed the structure of the polysaccharide.

Structure of the O-specific polysaccharide of the bacterium Providencia alcalifaciens O23 containing a novel component: an amide of D-glucuronic acid with N(epsilon)-(1-carboxyethyl)lysine.

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Providencia alcalifaciens O23 and found to contain D-glucose, D-galactose, 2-acetamido-2-deoxy-D-galactose, and N epsilon-(1-carboxyethyl)-N alpha-(D-glucuronoyl)lysine. On the basis of full and partial acid hydrolyses, selective solvolysis with anhydrous hydrogen fluoride, and 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H, 13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), the following structure of the liner tetrasaccharide repeating unit of the polysaccharide was established [structure: see text]

Structure of the O-specific polysaccharide of the bacterium Proteus mirabilis O13 containing a novel component: an amide of D-galacturonic acid with N(epsilon)-(1-carboxyethyl)lysine.

An acidic O-specific polysaccharide was obtained by mild degradation of the lipopolysaccharide of the bacterium Proteus mirabilis O13 and found to contain D-galactose, 2-acetamido-2-deoxy-D-glucose, and N(epsilon)-(1-carboxyethyl)-N(alpha)-(D-galacturonoyl)lysine. On the basis of full acid hydrolysis and 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H, 13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), the following structure of the branched trisaccharide repeating unit of the polysaccharide was established [structure: see text]

Structure of the O-specific polysaccharide of Hafnia alvei PCM 1222 containing 2-aminoethyl phosphate.

The O-specific polysaccharide of H. alvei strain PCM 1222 has a branched hexasaccharide repeating unit containing D-galactose, L-rhamnose, D-ribose, D-galacturonic acid, and 2-acetamido-2-deoxy-D-glucose in the ratios 1:2:1:1:1, as well as 2-aminoethyl phosphate (EtNP) and O-acetyl groups in nonstoichiometric amounts. The polysaccharide was modified by carboxyl reduction, O-deacetylation, and dephosphorylation with 48% hydrofluoric acid, the last reaction being accompanied by removal of the lateral residue of beta-galactofuranose. The modified polysaccharides were studied by methylation analysis and 1H and 13C NMR spectroscopy, including 2D correlation spectroscopy (COSY), H-detected 1H,13C and 1H,31P heteronuclear multiple-quantum coherence (HMQC), 1D NOE, 2D rotating-frame NOE spectroscopy (ROESY), and 2D combined total correlation spectroscopy (TOCSY) and ROESY (TORO). The following structure of the O-deacetylated polysaccharide was established: [formula: see text] In different batches of the polysaccharide, the content of EtNP varied from 0.35 to 0.55 and that of the O-acetyl groups from 0.05 to 0.4 per repeating unit. It was tentatively suggested that the O-acetyl group is located at position 4 of a rhamnosyl residue.

Structural study and serological characterisation of the O-specific polysaccharide of Hafnia alvei PCM 1185, another Hafnia O-antigen that contains 3,6-dideoxy-3-[(R)-3-hydroxybutyramido]-D-glucose.

The O-specific polysaccharide of H. alvei strain PCM 1185 contains D-glucose, D-glucuronic acid, 2-acetamido-2-deoxy-D-glucose, and 3,6-dideoxy-3-[(R)-3-hydroxybutyramido]-D-glucose (Qui3NAcyl) in the ratios 2:1:1:1 as well as O-acetyl groups. On the basis of sugar and methylation analyses of the polysaccharide before and after chemical modifications (O-deacetylation, carboxyl reduction, Smith degradation), as well as 1H and 13C NMR spectroscopy, including 1D sequential, selective spin-decoupling, 2D homonuclear and 13C,1H heteronuclear correlation spectroscopy (COSY), and 2D rotating-frame NOE spectroscopy, it was found that the polysaccharide has a pentasaccharide repeating unit with the following structure: [formula: see text] with O-acetyl groups present in nonstoichiometric amounts, mainly at position 2 of GlcA and position 6 of GlcNAc or lateral Glc. Serological study showed that H. alvei strain PCM 1185 can be placed in a new serotype D and that an O-acetyl group can be a part of its epitope.

Structure of a new N-acetylisomuramic acid-containing O-specific polysaccharide of Proteus penneri strains 19 and 35.

O-Specific polysaccharides, together with oligosaccharide products of their degradation, were isolated by GPC after mild acid delipidation of lipopolysaccharides of Proteus penneri strains 19 and 35. The polysaccharides had the same trisaccharide repeating unit containing one residue each of D-galactose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-3-O-[(S)-1-carboxyethyl]-2-deoxy-D-glucose (N-acetylisomuramic acid). On the basis of 1D and 2D 1H and 13C NMR spectroscopy, including 2D correlation spectroscopy (COSY), rotating-frame NOE spectroscopy (ROESY), and H-detected heteronuclear 1H,13C multiple-quantum coherence (HMQC), the following structure of the repeating unit was established: [formula: see text]. The oligosaccharide products formed by cleavage of the glycosidic linkage of GlcNAc represent a chemical trisaccharide repeating unit of the polysaccharide and its oligomer homologs. The ease of hydrolysis of the polysaccharide is associated with the closeness of the glycosyl group and the lactic acid residue in N-acetylisomuramic acid. The polysaccharides studied are structurally related to the O-specific polysaccharides of P. penneri strains 62 and 71 studied by us earlier.

Structure of the O-specific polysaccharide of Hafnia alvei 1204 containing 3,6-dideoxy-3-formamido-D-glucose.

The O-specific polysaccharide of Hafnia alvei strain 1204 has a hexasaccharide repeating unit containing D-mannose, D-glucuronic acid, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, and 3,6-dideoxy-3-formamido-D-glucose (Qui3NFo) in the ratios 2:1:1:1:1 as well as O-acetyl groups. On the basis of methylation analysis of the intact, carboxyl-reduced, and Smith-degraded polysaccharide as well as 1D and 2D NMR spectroscopy, including 1D total correlation spectroscopy, 1D NOE spectroscopy, 2D homonuclear shift-correlated spectroscopy (COSY), and 13C,1H heteronuclear COSY, the following structure of the O-deacetylated polysaccharide was established: -->3)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->3)-beta-D-GlcpN Ac-(1--> -->2)-beta-D-Quip3NFo-(1-->3)-alpha-D-GalpNAc-(1-->4)-alpha-D-G lcpA-(1--> Location of the N-formyl group, occurring as two stereoisomers in the ratio approximately 3:1, was determined by an NOE on H-3 Qui3N arising on pre-irradiation of HCO of the minor (E) isomer. The O-acetyl groups are attached in nonstoichiometric amounts at position 3 of GlcA and position 6 of a mannose residue or GlcNAc.

[Structure of lipopolysaccharides from gram-negative bacteria. III. Structure of O-specific polysaccharides]. / Stroenie lipopolisakharidov gramotritsatel'nykh bakterii. III. Struktura O-spetsificheskikh polisakharidov.

Data on the composition and structure of O-antigens which represent polysaccharide chains of outer membrane lipopolysaccharides of gram-negative bacteria defining cell immunospecificity are reviewed with special reference to some structural features of O-antigens, such as masked regularity and occurrence in one microorganism of lipopolysaccharides with two structurally distinct polysaccharide chains. Antigenic relationships between the microorganisms belonging to different taxonomic groups are discussed.

[Synthesis and study of NMR spectra and conformations of branched oligosaccharides. 2,3-di-O-glycosylated methyl-alpha-L-rhamnopyranosides with one or two 2-acetamido-2-deoxy-beta-D-glucopyranosyl residues]. / Sintez i issledovanie spektrov IaMR i konformatsii razvetvlennykh oligosakharidov. 2,3-Di-O-glikozilirovannye metil-alpha-L-ramnopiranozidy s odnim ili dvumia 2-atsetamido-2-dezoksi-beta-D-gliukopiranozil'nymi ostatkami.

A series of methyl 2,3-di-O-glycosyl-alpha-L-rhamnopyranosides with 2-acetamido-2-deoxy-beta-D-glucopyranosyl substituents have been synthesized and the deviations from additivity (delta delta) in their 13C-NMR spectra determined. It is shown that the delta delta values for the trisaccharides with the GlcNAc substituent at O-2 of the diglycosylated Rha may markedly differ from the delta delta values in the spectra of the respective trisaccharides with the Glc substituent. These deviations are probably associated with the intramolecular spatial interactions with participation of the NHAc-group.

The structure of the O-specific polysaccharide of Salmonella arizonae O21 (Arizona 22) containing N-acetylneuraminic acid.

The O-specific polysaccharide of S. arizonae O21 was found to contain 2-acetamido-2-deoxy-D-glucose, 2-acetamidino-2,6-dideoxy-L-galactose, N-acetylneuraminic acid, and O-acetyl groups. On the basis of 1H and 13C NMR studies of the intact and O-deacetylated polysaccharide and oligosaccharide fragments obtained by solvolysis with anhydrous hydrogen fluoride, partial methanolysis and partial hydrolysis, it was concluded that the O-specific polysaccharide has the following structure: [formula: see text]

The structure of the O-specific polysaccharide of Hafnia alvei strain 1216.

The O-specific polysaccharide of Hafnia alvei strain 1216 is composed of D-galactose, D-glucuronic acid, 2-acetamido-2-deoxy-D-glucose, 3,6-dideoxy-3-[(R)-3-hydroxybutyramido]-D-glucose, and O-acetyl groups in the ratios 1:1:2:1:1. On the basis of sugar and methylation analyses of the intact and chemically degraded (O-deacetylated, carboxyl-reduced, Smith-degraded) polysaccharide and 1H and 13C NMR spectroscopy, including 2D shift-correlated (COSY, relayed COSY, 13C, 1H-COSY) and 1D NOE spectroscopy, it was concluded that the O-antigen is built up of linear pentasaccharide units having the following structure: [formula: see text]

The structure of the O-specific polysaccharide of Salmonella arizonae O62.

The O-specific polysaccharide was liberated by mild acid hydrolysis of the lipopolysaccharide (LPS) isolated from S. arizonae O62 by phenol-water extraction. The branched hexasaccharide repeating-unit of the O-specific chain of the O62 LPS contained L-rhamnose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2-deoxy-D-galacturonic acid in molar ratios of 4:1:1. On the basis of methylation analysis, 1H and 13C NMR spectroscopy, including 2D shift-correlated (COSY) and 1D NOE spectroscopy, the following structure for the repeating unit of the O-specific polysaccharide was established: [formula: see text]

The structure of the O-specific polysaccharide of Citrobacter O16 containing glycerol phosphate.

The O-specific polysaccharide, obtained by mild acid degradation of Citrobacter O16 lipopolysaccharide, consists of D-glucose, D-galactose, 2-acetamido-2-deoxy-D-galactose, glycerol and phosphate in the ratios 2:2:2:1:1. Selective cleavage of the polysaccharide was carried out by Smith degradation, N-deacetylation-deamination and dephosphorylation with 48% hydrofluoric acid, which was accompanied by unexpected splitting of one of the glycosidic linkages. The structures of the oligosaccharides thus obtained were established using 1H- and 13C-NMR spectroscopy, including one-dimensional NOE, two-dimensional rotating-frame NOE, homonuclear and heteronuclear 13C, 1H correlation spectroscopy, and, for the Smith degradation product, positive- and negative-ion-mode fast-atom-bombardment MS and MS/MS with collision-induced dissociation. On the basis of these data and the results of methylation analysis, it was concluded that the O-specific polysaccharide has the following repeating unit structure: [formula: see text]

Synthesis of 2,3-di-O-glycosyl derivatives of methyl alpha- and beta-D-glucopyranoside.

The syntheses are described of 2,3-di-O-glycosyl derivatives of methyl alpha- and beta-D-glucopyranoside having alpha-D-manno-, beta-D-galacto-, alpha-L-rhamno-, alpha-L-fuco-, and beta-L-fuco-pyranosyl substituents at O-2 and O-3. The syntheses involved glycosylation of methyl 4,6-O-benzylidene-alpha- (24) and -beta-D-glucopyranoside (21), and substituted derivatives of 21 bearing 2-O-(2,3,4,6-tetra-O-benzoyl-alpha-D-mannopyranosyl)-, -(2,3,4,6-tetra-O- acetyl-beta-D-galactopyranosyl)-, -(2,3,4,-tri-O-benzoyl-alpha-L- rhamnopyranosyl)-, and -(2,3,4-tri-O-benzoyl-beta-L-fucopyranosyl) groups.