Structural studies on Klebsiella type 61 capsular polysaccharide

The capsular polysaccharide from klebsiella type 61 was found to contain d-galactose, d-glucose, d-mannose, and d-glucuronic acid in the ratios 1:2:1:1. Acid hydrolysis of the polysaccharide gave one aldobiouronic acid, whose structure was established. Methylation analysis of the polysaccharide provided information about the linkages in the polysaccharide. The polysaccharide is composed of a pentasaccharide repeating unit for which structures are proposed.     

Structural studies of the capsular polysaccharide from Klebsiella type 1

The structure of the capsular polysaccharide from Klebsiella type 1, which is composed of D-glucose, D-glucuronic acid, L-fucose, and pyruvic acid (1:1:1:1), has been investigated. Methylation analysis, n.m.r. spectroscopy, graded hydrolysis, and periodate-oxidation studies were the principal methods used. These studies demonstrated that the polysaccharide consists of the following trisaccharide repeating-unit:

     

Structural studies of the capsular polysaccharide of Klebsiella type 37

The structure of the Klebsiella type 37 capsular polysaccharide has been investigated. Methylation analysis, various specific degradations, and n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the structure 4-O-Lac-d-GlcA  4-O-[(S)-1-carboxyethyl]-d-glucuronic acid:

     

Structural studies of the capsular polysaccharide of Klebsiella type 28

The capsular polysaccharide from Klebsiella type 28 has been studied by methylation analysis, a modified Smith-degradation procedure, and uronic acid degradation with subsequent oxidation and elimination of the substituents of the oxidized residue. The polysaccharide contained the hexasaccharide repeating-unit shown below. The terminal D-glucopyranose residue was hydrolysed by emulsin, indicating a β linkage. The anomeric natures of other glycosidic linkages were determined by characterization of fragments obtained during the degradative studies. The D-galactopyranose residue was not present in any fragment, but is assumed to be α-linked from optical-rotation considerations.

     

The Molecular Structure of the capsular polysaccharide from Klebsiella Type 27

The capsular polysaccharide of Klebsiella serotype K27 has been investigated by techniques involving methylation analysis, autohydrolysis, and graded hydrolysis with acid. The anomeric configurations of the sugar constituents were determined, where possible, on the basis of p.m.r. spectroscopy and optical rotation data. The results of these studies are consistent with a primary structure in which the repeating-unit is the doubly branched hexasaccharide:

     

The structure of Klebsiella serotype 11 capsular polysaccharide

Using periodate oxidation, methylation analysis, the characterization of oligosaccharides obtained by partial acid hydrolysis, p.m.r. spectroscopy, and analytical ultracentrifugation, the structure of the (mildly alkali-treated) Klebsiella serotype 11 capsular polysaccharide has been elucidated. The tetrasaccharide repeating-unit comprises the sequence ?3)-β-D-Glcp-(1?3)-β-D-GlcUAp-(1?3)-α-D-Galp-(1→ with a 4,6-O-(1-car?yethylidene)-α-D-galactosyl residue linked to O-4 of the glucuronic acid residue. The structural basis for some serological cross-reactions of the Klebsiella K11 antigen is discussed, and it is shown that rabbit antisera against the Klebsiella K11 test-strain predominantly contain K agglutinins specific for branch-terminal 4,6-O-(1-car?yethylidene)-D-galactose.     

Primary structure of the Klebsiella serotype 16 capsular polysaccharide

The primary structure of the Klebsiella serotype 16 capsular polysaccharide consists of tetrasaccharide repeating-units comprising a/ar3)-α-D-Glcp-(1/ar4)β-D-GlcAp-(1/ar4)-α-L-Fucp-(1/ar chain with a β-D-Galp-(1→ branch at position 4 of the D-glucosyl residue.     

Structural investigation of the capsular polysaccharide of Klebsiella serotype 55

The structure of the capsular polysaccharide from Klebsiella type 55 has been investigated by using the techniques of methylation, Smith periodate oxidation, and partial, acid hydrolysis. The anomeric configurations of the glycosidic linkages were determined by performing ¹H-n.m.r. and ¹³C-n.m.r.spectroscopy on the polysaccharide and derived poly- and oligo-saccharides obtained through degradative procedures. The position of the O-acetyl group was located by devising an improved method for its replacement by a methyl ether group. The structure was shown to consist of the following tetrasaccharide repeating unit.     

Structural investigation of the capsular polysaccharide of Klebsiella serotype k23

Klebsiella K23 capsular polysaccharide has been investigated by the techniques of hydrolysis, methylation, Smith degradation-periodate oxidation, and base-catalysed degradation, either on the original or the carboxyl-reduced polysaccharide. The structure was found to consist of a tetrasaccharide repeating-unit, as shown below. The anomeric configurations of the sugar residues were determined by ₁H-and ¹³C-n.m.r. spectroscopy on the original and degraded polysaccharides.

     

Structural investigation of the capsular polysaccharide of Klebsiella serotype K80

The use of methylation, periodate oxidation, β-elimination, and selective hydrolysis enabled the structure of the K80 polysaccharide to be determined. The nature of the anomeric linkages was established by ¹H-n.m.r. spectroscopy, and confirmed by the results of oxidation of the fully acetylated polysaccharide with chromic acid. The K80 polysaccharide is comprised of repeating units of the pentasaccharide shown, and contains a pyruvic acetal on each repeating unit. This pattern constitutes the first instance, in this series of polysaccharides, of a pyruvic acetal attached to a side-chain rhamnosyl group.

     

Acylated oligosaccharides from Klebsiella K63 capsular polysaccharide: Depolymerization by partial hydrolysis and by bacteriophage-borne enzymes

The extracellular polysaccharide from Klebsiella K63 is unique in having acetic and formic ester groups attached to the d-galactopyranosyluronic residues in the trisaccharide repeating-sequence. These O-acyl substituents are shown to be some what resistant to mild hydrolysis by both acid and alkali. Bacteriophage-induced depolymerization of the polysaccharide generated a series of acylated oligosaccharides comprising one, or more, repeating unit(s). By mild hydrolysis with acid, the same series of oligomers was released from the polysaccharide, together with the corresponding non-acylated compounds and the expected acylated and non-acylated aldobiouronic acids. A study of these oligosaccharides, as well as of a number of their related compounds, is described, with particular emphasis on the methods used to locate the formic and acetic ester groups. The location of the O-acyl substituents on the galactosyluronic residues was further supported by the results obtained from the high-resolution, 400-MHz, p.m.r. spectra and ¹³C-n.m.r. spectra of a number of the oligosaccharides.     

Structure of the capsular polysaccharide from Streptococcus pneumoniae type 23

The capsular polysaccharide from Streptococcus pneumoniae Type 23 (S-23) was found to contain d-galactose, d-glucose, l-rhamnose, glycerol, and phosphorus in the ratios of 1:1:2:0.6:1. Methylation analysis provided information about the linkages of the different sugar units. The sequence of the different sugar residues was confirmed by Smith degradation. Oxidation of S-23 with chromium trioxide indicated that all of the sugar units have the β configuration. The results suggest the following structure for the repeating unit.

     

Molecular structure for microbial polysaccharides: conformation of the Klebsiella serotype K9 capsular polysaccharide

Fibre type X-ray diffraction patterns have been obtained from oriented, semicrystalline films prepared from the sodium salt form of the bacterial capsular polysaccharide of Klebsiella serotype K9. The molecule has a pentasaccharide repeating sequence, with four neutral residues in the backbone and a glucoronic acid side chain. A novel feature of the molecule is the incorporation of α-l-rhamnose residues, one 1,2 linked and two 1,3 linked in the backbone. Analysis of the X-ray diffraction results indicate an extended three-fold helical conformation with an axially projected chemical repeat of 1.377 nm. Both left and right handed helices have been examined using linked atom least squares techniques to optimize the stereochemistry while simultaneously meeting the observed helical parameters.     

Structural investigation of the capsular polysaccharide from Klebsiella serotype K-34 and its characterization by N.M.R. spectroscopy

The repeating unit of the capsular polysaccharide from Klebsiella type K-34 has been established by methylation, partial hydrolysis, and Smith degradation to consist of a hexasaccharide repeating-unit built up of four l-rhamnose, one d-glucose, and one d-galacturonic acid residues. The anomeric configurations of the linkages was determined by proton and ¹³C-n.m.r. spectroscopy at each step of the degradation procedures. Further evidence for the configurations of the glycosidic linkages involved the use of proton T₁ relaxation-times and oxidation by chromium trioxide. The data allowed assignment of the following structure for the repeating unit:     

Structural studies of the klebsiella type 47 capsular polysaccharide

The structure of the capsular polysaccharide from Klebsiella Type 47 has been investigated. Methylation analysis and characterization of oligosaccharides obtained on acid hydrolysis were the principal methods used. The polysaccharide is composed of tetrasaccharide repeating-units, and a structure for these units is proposed.     

Structural investigation of Klebsiella serotype K32 polysaccharide

The capsular polysaccharide from Klebsiella K32 has been studied by using methylation, periodate oxidation, and partial-hydrolysis techniques. The polysaccharide is shown to comprise the four-sugar repeating unit below. Features of interest in this structure include the presence of a β-linked l-rhamnosyl residue, and the extreme lability of the 1-carboxyethylidene acetal towards acid. N.m.r. spectroscopy was used extensively to establish the nature of the anomeric linkages and to identify oligosaccharides obtained by the various degradative techniques used.     

Strucrural investigation of Klebsiella serotype K7 polysaccharide

Methylation analysis of and partial hydrolysis studies on the Klebsiella K7 capsular polysaccharide and its carboxyl-reduced derivative indicated the recurrence of D-glucopyranuronic acid, D-mannopyranose, and D-glucopyranose residues, linearly linked in a specific manner, in the molecular structure. D-Galactopyranose and pyruvic acid residues are linked to the main chain on the D-mannose residues (at O-3) and the D-glucose residues (at O-4 and O-6), respectively; the simplest interpretation of this evidence is that nine sugar residues and pyruvic acid constitute a repeating unit. The sequence →3)-β-D-GlcAp-(1→2)-α-D-Manp-(1→2)-α-D-Manp-(1→3)-D-Glcp→ was demonstrated by the isolation from the polysaccharide of an aldotetraouronic acid of this structure.     

Structural investigation of Klebsiella serotype K70 polysaccharide

By using the techniques of methylation analysis, uronic acid degradation, partial hydrolysis, and periodate oxidation, the structure of the capsular polysaccharide from Klebsiella serotype K70 has been investigated. Nuclear magnetic resonance was used extensively to characterize fragments obtained as a result of the various degradation procedures. The existence of a linear, hexasaccharide repeating unit having a 1-carboxyethylidene group attached to a 2-linked α-l-rhamnosyl residue in every second repeating unit has been demonstrated.     

Structural investigation of Klebsiella serotype K36 polysaccharide

Klebsiella K36 capsular polysaccharide has been investigated by methylation, Smith-periodate oxidation and partial hydrolysis techniques. The structure was found to consist of a hexasaccharide repeating unit as shown. The anomeric configurations of the sugar were determined by ¹H and ¹³C n.m.r. spectroscopy on isolated oligomers obtained during the degradative studies and on the intact polysaccharide.     

Molecular structures for microbial polysaccharides: x-ray diffraction results from Klebsiella serotype K57 capsular polysaccharide

Fibre X-ray diffraction patterns have been obtained from oriented, semi-crystalline films of the Klebsiella capsular polysaccharide secrotype K57. K57 is a polytetrasaccharide that contains galactosyluronic acid, mannosyl, and galactosyl residues in the backbone, and an additional mannosyl group as a side-appendage. The simplest interpretation of the diffraction pattern is that the molecule crystallizes as a three-fold helix with an axially projected repeat of 1.143 nm which correlates directly with the chemical repeat. The chain is highly extended, even though it incorporates a 1,2-diaxial linkage in the main backbone. Molecular models have been built using least-squares techniques to minimise interatomic compression and simultaneously meet the observed helical parameters. These models have been compared with the experimental data by using cylindrically averaged, Fouriertransform calculations.