Structural studies on the specific type-14 pneumococcal polysaccharide.

The structure of the Pneumococcus type-14 capsular polysaccharide has been reinvestigated by using methylation analysis, different specific degradations, and n.m.r. spectroscopy. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the structure: (formula: see text).     

Structural studies of the O-specific side chain of the lipopolysaccharide from Escherichia coli O:7

The structure of the O-specific side-chain of the lipopolysaccharide from Escherichia coli O:7 has been investigated, using n.m.r. spectroscopy, methylation analysis, partial hydrolysis, and Smith degradation as the principal methods. It is concluded that the polysaccharide is constructed of repeating pentasaccharide units having the structure (formula; see text) where D-QuipNAc stands for 4-acetamido-4,6-dideoxy-D-glucopyranose. The 13C-n.m.r. spectrum of the polysaccharide has been interpreted completely.     

The structure of the neuraminic acid-containing capsular polysaccharide of Escherichia coli serotype K9

The acidic capsular polysaccharide isolated from Escherichia coli O9:K9:H12 was investigated by using n.m.r. spectroscopy, methylation analysis, periodate oxidation, and bacteriophage-borne enzyme degradation. The polysaccharide, the structure of which is shown below, is the third E. coli capsular polysaccharide reported to contain neuraminic acid, the others being the K1 and K92 polysaccharides, and it is the first in the E. coli series shown to contain a 4-linked neuraminic acid unit.     

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 5

The structure of the capsular polysaccharide (S5) elaborated by Streptococcus pneumoniae type 5 has been investigated by using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure: (Formula: see text) In this structure, L-PneNAc stands for 2-acetamido-2,6-dideoxy-L-talose (pneumosamine) and D-Sug for 2-acetamido-2,6-dideoxy-D-xylo-hexos-4-ulose. The latter sugar accounts for the lability of S5 towards alkali. N.m.r. spectra indicate heterogeneity in S5, most probably associated with the hexosyl-4-ulose residue.     

Structural studies of the Escherichia coli O-149 O-antigen polysaccharide

The structure of the O-antigen polysaccharide from Escherichia coli O-149 has been investigated; methylation analysis, partial hydrolysis with acid, and n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of trisaccharide repeating-units having the following structure. (Formula: see text). The absolute configuration at the acetalic carbon atom of the pyruvic acid residue is S.     

Structural studies of an extracellular polysaccharide (K21b) elaborated by Klebsiella type 21b

The capsular polysaccharide from a new capsular serotype of Klebsiella, K21b, has been investigated, using n.m.r. spectroscopy, methylation analysis, and specific degradations as the main methods. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text)     

Structural studies of the O-antigen from vibrio cholerae O:2

The structure of the O-antigen from Vibrio cholerae O:2 has been investigated, mainly by methylation analysis, specific degradations, and n.m.r. spectroscopy, and concluded to involve the trisaccharide repeating-unit in which QuiNAc is 2-acetamido-2,6-dideoxyglucose and Sug is tentatively assigned as 5-acetamidino-7-acetamido-3,5,7,9-tetradeoxy- -glycero-β- -manno-nonulosonic acid. The acetamidino group is basic and, consequently, the polysaccharide is neutral. When this group is transformed into an N-acetyl group, by treatment with aqueous triethylamine, the polysaccharide becomes acidic.     

Structure of the capsular polysaccharide of Escherichia coli O9:K32(A):H19

The capsular polysaccharide of the bacterium Escherichia coli O9:K32(A):H19 was analyzed using chemical methods (hydrolysis, sequential Smith degradation, methylation analysis) together with 1H- and 13C-n.m.r. spectroscopy. 13C-N.m.r. spectroscopy and chemical analyses indicated that the K32 polysaccharide is composed of equimolar proportions of glucose, galactose, rhamnose, and glucuronic acid, and carries O-acetyl groups. 1H-N.m.r. analysis of native K32 polysaccharide revealed five resonances in the anomeric region (delta 5.52, 5.16, 5.12, 5.02, and 4.73) and the presence of an acetyl group (delta 2.18). O-Deacetylation of the polysaccharide resulted in the loss of the resonance at delta 2.18 and one of the resonances (delta 5.52) in the anomeric region. The "extra" anomeric resonance in the 1H-n.m.r. spectrum of the native K32 polymer was assigned to H-2 of rhamnose, which experiences a large downfield shift when the 2-position is O-acetylated. This was confirmed by a 2D-COSY n.m.r. experiment and studies of model compounds. The K32 capsular polysaccharide is of the "2 + 2" type, comprised of the following repeating unit: (sequence; see text) This structure is identical to that of Klebsiella K55 capsular polysaccharide.     

Structural studies of the polysaccharide antigen of Eubacterium saburreum, strain L. 452

The structure of the polysaccharide antigen produced by Eubacterium saburreum, strain L 452, has been investigated. Methylation analysis, graded hydrolysis with acid, and n.m.r. spectroscopy were the principal methods used. The polysaccharide is composed of trisaccharide repeating-units having the following structure:

The assignment of the β configuration to the d-ribofuranosyl residue is tentative.     

The use of bacteriophage depolymerization in the structural investigation of the capsular polysaccharide from Klebsiella serotype K3

The structure of the repeating unit of the capsular polysaccharide from Klebsiella serotype K3 has been established from the results of n.m.r. (1H and 13C) spectroscopy and methylation analysis of P1, the pyruvic acetal-bearing pentasaccharide obtained on depolymerization of the polysaccharide with a bacteriophage-borne endogalactosidase, reduced deacetalated P1, and the native polysaccharide. The data permit the assignment of the following structure to the repeating unit: (formula see text)     

Structural studies on the capsular polysaccharide of klebsiella strain 6412

The structure of the capsular polysaccharide from klebsiella strain 6412 has been investigated by methylation analysis and smith degradation. The anomeric natures of the glycosidic linkages were determined from the optical rotations and n.m.r. spectra of original and degraded materials. The polysaccharide contained the tetrasaccharide repeating-unit shown below.     

Structural studies of a rhamnogalacturonan from the stipules of Musanga cercropoides.

The major water-soluble polysaccharide isolated from the stipules of Musanga cercropoides has been investigated, using n.m.r. spectroscopy, methylation analysis, and solvolysis in liquid hydrogen fluoride as the main methods. It is concluded that the polysaccharide is of the rhamnogalacturonan type and is, at least mainly, composed of tetrasaccharide repeating-units having the following structure [formula: see text] The polysaccharide further contains approximately two O-acetyl groups per repeating unit, which have not been located.     

Structural studies of the polysaccharide antigen of Eubacterium saburreum, Strain L 32

The structure of the polysaccharide antigen produced by Eubacterium saburreum, strain L 32, has been investigated. The principal methods used were methylation analysis, graded hydrolysis with acid, and n.m.r. spectroscopy. The polysaccharide, which contains the unusual sugar 3,6-dideoxy-D-arabino-hexose (tyvelose, Tyv), is composed of trisaccharide repeating-units having the following structure:

     

Escherichia coli serotype-39 capsular polysaccharide: primary structure and depolymerisation by a bacteriophage-associated glycanase

The acidic capsular polysaccharide isolated from Escherichia coli O9:K39:H9 was investigated, using n.m.r. spectroscopy, methylation analysis, uronic acid degradation of the native and methylated polysaccharides, and bacteriophage-associated enzyme degradation. The structure of the repeating unit, which is shown below, is identical to that reported for Klebsiella serotype-61 capsular polysaccharide. (formula; see text)     

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 18A

The structure of the capsular polysaccharide (S18A) elaborated by Streptococcus pneumoniae type 18A has been investigated by using methylation analysis and n.m.r. spectroscopy. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text) In this structure, the absolute configuration of the glycerol 1-phosphate moiety has not been determined but is assumed to be D from biosynthesis considerations. The structure of S18A is, as expected, closely similar to those determined for S18F and S18C.     

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 from Streptococcus pneumoniae type 7A

Application of methylation analysis, specific degradations, and n.m.r. spectroscopy to the capsular polysaccharide elaborated by Streptococcus pneumoniae type 7A indicates a hexasaccharide repeating-unit with the structure (Formula; see text).     

Structural determination of the capsular polysaccharide of Streptococcus pneumoniae type 19A (57)

The structure of the Pneumococcus type 19A (57) capsular polysaccharide has been reinvestigated by using methylation analysis and n.m.r. spectroscopy. It is composed of residues of 2-acetamido-2-deoxy-d-mannose, d-glucose, l-rhamnose, and phosphate in the molar ratios of 1:1:1:1. The polysaccharide is linear, and is composed of these components in a repeating unit of the following structure.

The type 19A polysaccharide (Na⁺ salt) was depolymerized by heating it in water at 100°, conditions that also hydrolyzed the newly formed phosphoric monoesters.     

Structural studies of the capsular polysaccharide of Klebsiella type 33.

The structure of the capsular polysaccharide from Klebsiella type 33 has been investigated. Methylation analysis, various specific degradations, graded hydrolysis with acid, and n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula, see manual). The D-galactopyranosyl group, with pyruvic acid linked as a ketal to O-3 AND O-4, was degraded on treatment of the fully methylated polysaccharide with strong base. It is proposed that methyl pyruvate is eliminated, in an E2 type of reaction.     

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 18F

The structure of the capsular polysaccharide elaborated by Streptococcus pneumoniae type 18F (S18F) has been investigated by using n.m.r. spectroscopy, methylation analysis, and characterisation of oligosaccharides obtained on partial hydrolysis. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text) In this structure, the absolute configuration of the glycerol phosphate moiety has not been determined, but is assumed to be D-glycerol 1-phosphate (sn-glycerol 3-phosphate). The location of an O-acetyl group at O-6 of the terminal alpha-D-glucopyranosyl groups is tentative only.