Structure of the O-specific polysaccharide of Proteus vulgaris O15 containing a novel regioisomer of N-acetylmuramic acid, 2-acetamido-4-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucose

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Proteus vulgaris O15 and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, ROESY, and H-detected 1H,(13)C HMQC experiments. The polysaccharide was found to contain an ether of GlcNAc with lactic acid, and the following structure of the repeating unit was established:-->3)-alpha-D-GlcpNAc4(R-Lac)6Ac-(1-->2)-beta-D-GlcpA-(1-->3)-alpha-L-6dTalp2Ac-(1-->3)-beta-D-GlcpNAc-(1-->where L-6dTal and D-GlcNAc4(R-Lac) are 6-deoxy-L-talose and 2-acetamido-4-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucose, respectively. The latter sugar, which to our knowledge has not been hitherto found in nature, was isolated from the polysaccharide by solvolysis with anhydrous triflic acid and identified by comparison with the authentic synthetic compound. Serological studies with the Smith-degraded polysaccharide showed an importance of 2-substituted GlcA for manifesting of the immunospecificity of P. vulgaris O15.     

Structure of the O-specific polysaccharide from Shewanella japonica type strain KMM 3299T containing the rare amino sugar Fuc4NAc

An acidic O-specific polysaccharide (PS) of the agar-digesting bacterium Shewanella japonica with the type strain KMM 3299(T) was obtained by mild acid hydrolysis of the lipopolysaccharide. The polysaccharide was studied by component analysis, methylation analysis, (1)H and (13)C NMR spectroscopy, including 2D NMR experiments. The PS was determined to have the following structure involving three unusual amino sugars:     

Structure of the O-polysaccharide of Proteus serogroup O34 containing 2-acetamido-2-deoxy-alpha-D-galactosyl phosphate

On mild acid degradation of the lipopolysaccharide of Proteus vulgaris O34, strain CCUG 4669, the O-polysaccharide was cleaved at a glycosyl-phosphate linkage that is present in the main chain. The resultant phosphorylated oligosaccharides and an alkali-treated lipopolysaccharide were studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, and the following structure of the branched tetrasaccharide phosphate repeating unit of the O-polysaccharide was established: [carbohydrate structure: see text]The O-polysaccharide of Proteus mirabilis strain TG 276 was found to have the same structure and, based on the structural and serological data, this strain was proposed to be classified into the same Proteus serogroup O34.     

Structure of a glucosyl phosphate-containing O-polysaccharide of Proteus vulgaris O42

An O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Proteus vulgaris O42 and studied by sugar and methylation analyses along with 1H, 13C and 31P NMR spectroscopy. The following structure of the polysaccharide having a linear pentasaccharide phosphate repeating unit was established: -->3)-alpha-L-FucpNAc4Ac-(1-->4)-alpha-D-Glcp-1-P-(O-->4)-alpha-D-GlcpNAc-(1-->3)-alpha-L-FucpNAc4Ac-(1-->3))-alpha-D-GlcpNAc6Ac-(1--> where the degree of O-acetylation is approximately 80% on GlcNAc and approximately 40% on each of the FucNAc residues. A weak serological cross-reaction of anti-P. vulgaris O42 serum with the lipopolysaccharide of P. vulgaris O39 was observed and accounted for by the sharing of a disaccharide fragment of the O-polysaccharides.     

Structure of the O-polysaccharide of Proteus vulgaris O44: a new O-antigen that contains an amide of D-glucuronic acid with L-alanine

The O-polysaccharide of Proteus vulgaris O44, strain PrK 67/57 was studied by 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, ROESY, H-detected 1H, 13C HMQC, HMQC-TOCSY and HMBC experiments. The polysaccharide was found to contain an amide of D-glucuronic acid with L-alanine [D-GlcA6(L-Ala)], and the following structure of the linear pentasaccharide repeating unit was established: [structure: see text]. The structural data of the O-polysaccharide and the results of serological studies with P. vulgaris O44 O-antiserum showed that the strain studied is unique among Proteus bacteria, which is in agreement with its classification in a separate Proteus serogroup, O44.     

Structure of the O-polysaccharide from the lipopolysaccharide of Providencia stuartii O43 containing an amide of D-galacturonic acid with L-serine

The O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia stuartii O43:H28 and studied by sugar and methylation analyses, Smith degradation and 1H and 13C NMR spectroscopy, including 2D ROESY, and H-detected 1H, 13C HSQC and HMBC experiments, as well as a NOESY experiment in a 9:1 H2O/D2O mixture to reveal correlations for NH protons. It was found that the polysaccharide is built up of linear tetrasaccharide repeating units containing an amide of D-galacturonic acid with L-serine [D-GalA6(L-Ser)] and has the following structure:[3)-beta-D-GalpA6(L-Ser)-(1-->3)-beta-D-GlcpNAc-(1-->2)-alpha-D-Rhap4NAc-(1-->4)-beta-D-GlcpA-(1-->]n.     

Structure of the O-polysaccharide of Proteus mirabilis CCUG 10705 (OF) containing an amide of D-galacturonic acid with L-alanine

The structure of the O-polysaccharide of Proteus mirabilis CCUG 10705 (OF) was determined by chemical analyses along with one- and two-dimensional (1)H and (13)C NMR spectroscopy. The polysaccharide was found to contain an amide of D-galacturonic acid with L-alanine and based on the uniqueness of the O-polysaccharide structure and serological data, it was suggested to classify P. mirabilis OF into a new separate Proteus serogroup, O74. A weak cross-reactivity of P. mirabilis OF and P. mirabilis O5 was observed and accounted for by a similarity of their O-repeating units. The following structure of the polysaccharide of P. mirabilis OF was established: [chemical structure: see text]     

Structural determination of the O-antigenic polysaccharide from Salmonella Mara (O:39)

The O-antigenic polysaccharide of Salmonella Mara O:39 (formerly Q) was investigated by sugar and methylation analyses, absolute configuration assignment, mass spectrometry and NMR spectroscopy. The experiments revealed an O-polysaccharide chain composed of the following linear tetrasaccharide repeating units with the structure:→2)-α-l-Quip3NAc-(1→3)-α-d-Manp-(1→3)-α-l-Fucp-(1→3)-α-d-GalpNAc-(1→where α-l-Quip3NAc is the residue of 3-acetamido-3,6-dideoxy-α-l-glucopyranose. This repeating unit is the first published structure of the O-polysaccharide from 27 serotypes of Salmonella bacteria belonging to serogroup O:39 in the Kauffmann-White classification system.     

Structure of the O-polysaccharide of Citrobacter youngae O1 containing an alpha-D-ribofuranosyl group

The lipopolysaccharide of Citrobacter youngae O1, strain PCM 1492 was degraded with acid or alkali under mild conditions, and the resultant polysaccharide was isolated by GPC and studied by sugar and methylation analyses and 1H and 13C NMR spectroscopies, including 2D COSY, TOCSY, NOESY and 1H, 13C HSQC experiments. The following structure of the branched tetrasaccharide repeating unit of the O-polysaccharide was established: [structure: see text] where substitution with the alpha-D-Ribf group is nonstoichiometric. This group occurs rarely in bacterial polysaccharides and is easily cleaved under mild acidic conditions. Studies with polyclonal rabbit antisera against whole cells of C. youngae PCM 1492 and PCM 1506 showed the serological identity of the lipopolysaccharides of C. youngae PCM 1492, PCM 1493 and PCM 1506, which are classified in serogroup O1.     

Structure of the O-polysaccharide of Providencia alcalifaciens O21 containing 3-formamido-3,6-dideoxy-D-galactose

The O-polysaccharide (O-antigen) of Providencia alcalifaciens O21 was obtained by mild acid degradation of the lipopolysaccharide and studied by chemical methods and NMR spectroscopy. It was found that the polysaccharide is built up of branched pentasaccharide repeating units with a terminal residue of 3-formamido-3,6-dideoxy-D-galactose (D-Fuc3NFo) and has the following structure: [structure: see text]. Anti-P. alcalifaciens O21 serum cross-reacted with the O-antigen of Proteus vulgaris O47, which contains a GalNAc trisaccharide similar to that present in the P. alcalifaciens O21 O-polysaccharide.     

Structure of the O-polysaccharide and serological studies of the lipopolysaccharide of Proteus penneri 60 classified into a new Proteus serogroup O70

An alkali-treated lipopolysaccharide of Proteus penneri strain 60 was studied by chemical analyses and 1H, 13C and 31P NMR spectroscopy, and the following structure of the linear pentasaccharide-phosphate repeating unit of the O-polysaccharide was established: 6)-alpha-D-Galp-(1-->3)-alpha-L-FucpNAc-(1-->3)-alpha-D-GlcpNAc-(1-->3)-beta-D-Quip4NAc-(1-->6)-alpha-D-Glcp-1-P-(O--> Rabbit polyclonal O-antiserum against P. penneri 60 reacted with both core and O-polysaccharide moieties of the homologous LPS. Based on the unique O-polysaccharide structure and serological data, we propose to classify P. penneri 60 into a new, separate Proteus serogroup O70. A weak cross-reactivity of P. penneri 60 O-antiserum with the lipopolysaccharide of Proteus vulgaris O8, O15 and O19 was observed and discussed in view of the chemical structures of the O-polysaccharides.     

Structure of an acidic polysaccharide from the marine bacterium Pseudoalteromonas aliena type strain KMM 3562T containing two residues of L-serine in the repeating unit

The structure of an acidic polysaccharide from Pseudoalteromonas aliena type strain KMM 3562(T) has been elucidated. The polysaccharide was studied by component analysis, (1)H and (13)C NMR spectroscopy, including 2D NMR experiments. A (1)H, (13)C band-selective constant-time heteronuclear multiple-bond connectivity experiment was used to determine amide linkages, between serine and uronic acid (UA) residues, via (3)J(H,C) correlations between Ser-alphaH and UA-C-6. It was found that the polysaccharide consists of pentasaccharide repeating units with the following structure: [carbohydrate structure]; see text.     

Structures of two O-polysaccharides of the lipopolysaccharide of Citrobacter youngae PCM 1538 (serogroup O9)

Mild acid degradation of the lipopolysaccharide of Citrobacter youngae O9, strain PCM 1538 released a homopolysaccharide of 4-acetamido-4,6-dideoxy-D-mannose (D-Rha4NAc, N-acetyl-D-perosamine). Studies by methylation analysis and (1)H and (13)C NMR spectroscopy, using two-dimensional (1)H,(1)H COSY, TOCSY, NOESY and H-detected (1)H,(13)C HSQC experiments showed the presence of two structurally different polysaccharides consisting of the following units: -->)-alpha-D-Rhap4NAc-(1 --> and --> 3)-alpha-D-Rhap4NAc-(1 --> 3)-beta-D-Rhap4NAc-(1 -->.     

Structure of the O-polysaccharide of Escherichia coli O112ab containing L-iduronic acid

An acidic O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Escherichia coli O112ab and studied by sugar analysis along with (1)H and (13)C NMR spectroscopy. The O-polysaccharide was found to contain a rarely occurring sugar component, L-iduronic acid (L-IdoA), and the following structure of the branched pentasaccharide repeating unit was established: [structure: see text].     

A stereocontrolled synthesis of 3-acetamido-1,3,5-trideoxy- and 1,3,5,6-tetradeoxy-1,5-imino-d-glucitol

3-Acetamido-5-amino-3,5,6-trideoxy-d-glucono-1,5-lactam and 3-acetamido-5-amino-3,5-dideoxy-d-glucono-1,5-lactam were synthesized from corresponding 3-acetamido-3-deoxy-β-d-glucopyranosides in 63% and 35% overall yield, respectively. Acetylation followed by reduction led to the title 3-acetamido-3-deoxy derivatives of both deoxynojirimycin and 1,6-dideoxynojirimycin. The procedure developed is useful for a multi-gram scale.     

Structure and cross-reactivity of the O-antigen of Providencia stuartii O18 containing 3-acetamido-3,6-dideoxy-D-glucose

The O-polysaccharide (O-antigen) of Providencia stuartii O18 was obtained by mild acid degradation of the lipopolysaccharide and studied by chemical methods and NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, NOESY and 1H,13C HSQC experiments. The following structure of the tetrasaccharide repeating unit of the polysaccharide was established: [structure: see text] where Qui3NAc is 3-acetamido-3,6-dideoxyglucose. Anti-P. stuartii O18 serum cross-reacted with the O-antigen of Proteus genomospecies 4, which could be accounted for the marked structural similarities of the main chain.     

Structure of the O-polysaccharide of Idiomarina zobellii KMM 231T containing two unusual amino sugars with the free amino group, 4-amino-4,6-dideoxy-D-glucose and 2-amino-2-deoxy-L-guluronic acid

Mild acid degradation of the lipopolysaccharide of the bacterium Idiomarina zobellii, type strain KMM 231T, with aq 2% HOAc at 100 degrees C, yielded an oligosaccharide, which represents one repeating unit of the O-polysaccharide. A polysaccharide was obtained by mild base degradation of the lipopolysaccharide. The following structure of the O-polysaccharide was elucidated by 1H and 13C NMR spectroscopy of the oligosaccharide and base-degraded lipopolysaccharide, including COSY, TOCSY, ROESY, 1H, 13C HSQC, HSQC-TOCSY and HMBC experiments: [-->3)-alpha-D-Quip4N-(1-->4)-alpha-D-GlcpA-(1-->6)-alpha-D-GlcpNAc-(1-->4)-alpha-L-GulpNA-(1-->3)-beta-D-FucpNAc-(1-->] The O-polysaccharide is distinguished by the presence of two unusual amino sugars, 4-amino-4,6-dideoxy-D-glucose (D-Qui4N) and 2-amino-2-deoxy-L-guluronic acid (L-GulNA), both having the free amino group. The unexpectedly high acid lability of the glycosidic linkage of 2-acetamido-2,6-dideoxy-D-galactose (D-FucNAc) could be associated with the presence of a free amino group adjacent to the site of attachment of FucNAc to Qui4N.