Structure of the O-polysaccharide of Providencia stuartii O4 containing 4-(N-acetyl-L-aspart-4-yl)amino-4,6-dideoxy-D-glucose

The O-polysaccharide of Providencia stuartii O4 was obtained by mild acid degradation of the lipopolysaccharide, and the following structure of the pentasaccharide repeating unit was established: [structure: see text] where D-Qui4N(L-AspAc) is 4-(N-acetyl-L-aspart-4-yl)amino-4,6-dideoxy-D-glucose, which has not been hitherto found in bacterial polysaccharides. Structural studies were performed using sugar and methylation analyses, Smith degradation and NMR spectroscopy, including conventional 2D 1H,1H COSY, TOCSY, NOESY and 1H,13C HSQC experiments as well as COSY and NOESY experiments run in an H(2)O-D(2)O mixture to reveal correlations for NH protons.     

Structure of the O-polysaccharide of Providencia stuartii O49

The O-specific polysaccharide chain (O-antigen) of the lipopolysaccharide (LPS) of Providencia stuartii O49 was studied using sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including two-dimensional COSY, TOCSY, ROESY, H-detected 1H, 13C HSQC and HMBC experiments. The polysaccharide was found to have the trisaccharide repeating unit with the following structure: -->6)-beta-D-Galp(1-->3)-beta-D-GalpNAc(1-->4)-alpha-D-Galp(1-->     

Structure of the O-polysaccharide and serological cross-reactivity of the Providencia stuartii O33 lipopolysaccharide containing 4-(N-acetyl-D-aspart-4-yl)amino-4,6-dideoxy-D-glucose

The O-polysaccharide of Providencia stuartii O33 was obtained by mild acid degradation of the lipopolysaccharide and the following structure of the tetrasaccharide repeating unit was established: -->6)-alpha-D-GlcpNAc-(1-->4)-alpha-D-GalpA-(1-->3)-alpha-D-GlcpNAc-(1-->3)-beta-D-Quip4N(Ac-D-Asp)-(1-->, where d-Qui4N(Ac-D-Asp) is 4-(N-acetyl-D-aspart-4-yl)amino-4,6-dideoxy-D-glucose. Structural studies were performed using sugar and methylation analyses and NMR spectroscopy, including conventional 2D 1H, 1H COSY, TOCSY, NOESY and 1H, 13C HSQC experiments as well as COSY and NOESY experiments in an H2O-D2O mixture to reveal correlations for NH protons. The O-polysaccharide of P. stuartii O33 shares an alpha-D-GlcpNAc-(1-->3)-beta-D-Quip4N(Ac-D-Asp) epitope with that of Proteus mirabilis O38, which seems to be responsible for a marked serological cross-reactivity of anti-P. stuartii O33 serum with the lipopolysaccharide of the latter bacterium. P. stuartii O33 is serologically related also to P. stuartii O4, whose O-polysaccharide contains a lateral beta-D-Qui4N(Ac-L-Asp) residue.     

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 of Providencia alcalifaciens O19

Studies of the O-polysaccharide chain of the lipopolysaccharide (O-antigen) of Providencia alcalifaciens O19 by sugar and methylation analyses along with NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, NOESY and 1H,13C HSQC experiments, showed that the pentasaccharide repeating unit of the polysaccharide has the following structure: [structure: see text] where Fuc3NAc is 3-acetamido-3,6-dideoxygalactose. The unique structure of the O-antigen and serological data are in consistence with classification of this bacterium in a separate Providencia serogroup.     

New structure for the O-polysaccharide of Providencia alcalifaciens O27 and revised structure for the O-polysaccharide of Providencia stuartii O43

The O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide from Providencia alcalifaciens O27 and studied by sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, H-detected (1)H,(13)C HSQC, and HMBC experiments. It was found that the polysaccharide is built up of linear partially O-acetylated tetrasaccharide repeating units and has the following structure: [structure: see text] where Qui4NFo stands for 4-formamido-4,6-dideoxyglucose (4-formamido-4-deoxyquinovose). The O-polysaccharide structure of Providencia stuartii O43 established earlier was revised with respect to the configuration of the constituent 4-amino-4,6-dideoxyhexose (from Rha4N to Qui4N).     

The structure of the O-polysaccharide from the lipopolysaccharide of Providencia stuartii O47

The O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia stuartii O47:H4, strain 3646/51. Studies by sugar and methylation analyses along with Smith degradation and 1H and 13C NMR spectroscopy, including two-dimensional 1H,1H COSY, TOCSY, ROESY and H-detected 1H,13C HSQC and HMBC experiments, showed that the polysaccharide has a branched hexasaccharide repeating unit with the following structure: [carbohydrate structure: see text]     

The structure of the O-polysaccharide from the lipopolysaccharide of Providencia stuartii O57 containing an amide of D-galacturonic acid with L-alanine

The O-polysaccharide (O-antigen) was obtained by mild acid degradation of the lipopolysaccharide of Providencia stuartii O57:H29. Studies by sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, ROESY, H-detected (1)H,(13)C HSQC, and HMBC experiments, showed that the polysaccharide contains an amide of D-galacturonic acid with L-alanine and has the following pentasaccharide repeating unit: [formula: see text]     

The O-polysaccharide from the lipopolysaccharide of Providencia stuartii O44 contains L-quinovose, a 6-deoxy sugar rarely occurring in bacterial polysaccharides

The O-polysaccharide (O-antigen) of Providencia stuartii O44:H4 (strain 3768/51) was obtained by mild acid degradation of the lipopolysaccharide and studied by sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY, and H-detected (1)H,(13)C HSQC, and HMQC-TOCSY experiments. The O-polysaccharide was found to have a branched hexasaccharide repeating unit of the following structure: [Formula: see text].     

Structure of the O-polysaccharide and serological cross-reactivity of the lipopolysaccharide of Providencia alcalifaciens O32 containing N-acetylisomuramic acid

The O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O32 and studied by sugar and methylation analyses, solvolysis with triflic acid, 1H and 13C NMR spectroscopy, including two-dimensional 1H,1H COSY, TOCSY, ROESY, H-detected 1H,13C HSQC and HMBC experiments. It was found that the polysaccharide has a branched tetrasaccharide repeating unit containing 2-acetamido-3-O-[(S)-1-carboxyethyl]-2-deoxy-D-glucose (D-GlcNAc3Slac, N-acetylisomuramic acid) with the following structure: [STRUCTURE: SEE TEXT]. Serological studies with O-antisera showed antigenic relationships between P. alcalifaciens O32 and O29 as well as several other Providencia and Proteus strains sharing putative epitopes on the O-polysaccharides.     

Structure of the O-specific polysaccharide of Providencia alcalifaciens O16 containing N-acetylmuramic acid

The O-specific polysaccharide of Providencia alcalifaciens O16 was obtained by mild-acid degradation of the lipopolysaccharide and studied by chemical methods and NMR spectroscopy, including 2D 1H,(1)H COSY, TOCSY, NOESY, and 1H,(13)C HSQC experiments. It was found that the polysaccharide contains N-acetylmuramic acid, which was isolated by solvolysis with trifluoromethanesulfonic acid and identified by the specific optical rotation and NMR spectroscopy. The following structure of the trisaccharide repeating-unit of the polysaccharide was established:     

Structure of the O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O60

An O-polysaccharide (O-antigen) was isolated by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O60 and studied by sugar and methylation analyses as well as ¹H and ¹³C NMR spectroscopy, including 2D ROESY and ¹H,¹³C HMBC experiments in D₂O and a ROESY 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 pentasaccharide repeating units containing an amide of d-glucuronic acid with l-serine and has the following structure:The O-antigen studied is structurally and serologically closely related to the O-antigen of Proteus vulgaris O44.     

Structure of the O-specific polysaccharide of Proteus vulgaris O45 containing 3-acetamido-3,6-dideoxy-D-galactose

An O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Proteus vulgaris O45 and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, ROESY, H-detected 1H,13C HSQC and HMBC experiments. The following structure of the pentasaccharide repeating unit of the polysaccharide was established:-->6)-alpha-D-GlcpNAc-(1-->4)-alpha-D-GalpNAc-(1-->4)-alpha-D-GalpA-(1-->3)-beta-D-GlcpNAc-(1-->2)-beta-D-Fucp3NAc4Ac-(1-->where Fuc3NAc4Ac is 3-acetamido-4-O-acetyl-3,6-dideoxygalactose. A cross-reactivity of anti-P. vulgaris O45 serum was observed with several other Proteus lipopolysaccharides, which contains Fuc3N derivatives.     

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 from the lipopolysaccharide of Providencia alcalifaciens O28

An O-polysaccharide and oligosaccharides were isolated by GPC following mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O28. The O-polysaccharide was studied by sugar and methylation analyses, ¹H and ¹³C NMR spectroscopy, including 2D ROESY and H-detected ¹H,¹³C HSQC and HMBC experiments, and the following structure of the branched pentasaccharide repeating unit was established:This structure was confirmed by ESI MS of the isolated tridecasaccharide consisting of the lipopolysaccharide core and one O-polysaccharide repeat. The ESI mass spectrum also enabled inferring the composition of the core oligosaccharide.     

Structure of the O-polysaccharide of Providencia alcalifaciens O8 containing (2S,4R)-2,4-dihydroxypentanoic acid, a new non-sugar component of bacterial glycans

A glycerol teichoic acid-like O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O8 and studied by chemical methods and NMR spectroscopy, including 2D ROESY, {(1)H,(13)C} HSQC, and HMQC-TOCSY experiments. It was found that the compound contains a new component of bacterial lipopolysaccharides: ether-linked (2S,4R)-2,4-dihydroxypentanoic acid (Dhpa), which was identified by NMR spectroscopy. The following structure of the repeating unit of the polysaccharide was established:     

Structure of the O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O29

The O-polysaccharide was obtained by a mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O29. Structural studies were performed using sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including two-dimensional 1H, 1H COSY, TOCSY, ROESY, H-detected 1H, 13C HSQC and HMBC experiments. On the basis of the data obtained, the following structure of the branched tetrasaccharide repeating unit of the O-polysaccharide was established: [structure: see text].     

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 colitose-containing O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O6

The O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O6 and studied by sugar and methylation analysis, selective hydrolytic removal of 3,6-dideoxy-L-xylo-hexose (colitose, Col), (1)H and (13)C NMR spectroscopy, including 2D (1)H,(1)H COSY, TOCSY, ROESY and H-detected (1)H,(13)C HSQC and HMBC experiments. The polysaccharide was found to have a branched pentasaccharide repeating unit with the following structure: [see text] Remarkably, the trisaccharide side chain of the O6-polysaccharide represents a colitose ('3-deoxy-L-fucose') analogue of the H type 1 (precursor) antigenic determinant.