A study of 13CH coupling constants in hexopyranoses

Lipopolysaccharides from Pseudomonas aeruginosa 01 (Lhnyi classification), 0 3 (Habs classification), 0 1 3 and 014 (Wokatsch classification), and strain NCTC 8505, which is also related to serogroup 0 3 (Habs), have structurally similar 0-specific polysaccharide chains built up of tetrasaccharide repeating units involving L-rhamnose (Rha), 2-acetamido-2-deoxy-~-glucose (GlcNAc), 2-acetamido-2-deoxy-~-galacturonic acid (GalNAcA), and a di-N-acyl derivative of bacillosamine (BacN): 2,4-diacetamido-2,4,6-trideoxy-~-glucose or 2-acetamido-2,4,6-trideoxy-4-[(S)-3-hydroxybutyramido]-~-glucose. The latter derivative was obtained free by solvolysis with hydrogen fluoride of carboxyl-reduced Habs 0 3 polysaccharide, and was identified by 'H-nuclear magnetic resonance spectroscopy and by mass spectrometry of the corresponding methylated alditol. Habs 03, Lhnyi 01, and Wokatsch 014 polysaccharides contained 0-acetyl groups.Solvolysis with hydrogen fluoride of the native Habs 0 3 polysaccharide resulted in selective cleavage of the glycosidic linkages of 6-deoxy sugars to give the trisaccharide fragment involving all three N-acylated amino sugars. Similar solvolysis of NCTC 8505 polysaccharide afforded a mixture of disaccharide and trisaccharide with N,N'-diacetylbacillosamine at the reducing end. Smith degradation of Habs 0 3 polysaccharide resulted in selective oxidation of rhamnose to give a glycoside of a trisaccharide with glyceraldehyde as the aglycone. Smith degradation of NCTC 8505 polysaccharide was complicated by the formation of the glycoside of a trisaccharide with an aglycone of unknown structure. A trisaccharide with rhamnose at the reducing end was also isolated after Smith degradation of the latter polysaccharide.Analysis of the composition and structure of all oligosaccharides obtained, and detailed examination of the ' jc-nuclear magnetic resonance spectra of these oligosaccharides, and of both intact and modified

Section: D-bacp(nac)2-(crl -3)-~-rhap-(p 1 +mentioning

confidence: 99%

Somatic antigens of Pseudomonas aeruginosa

Knirel

Vinogradov

Shashkov

et al. 1986

“…The presence of Rhap in both anomeric configurations a and b was previously established on the Smith degraded product [2], whereas the a configuration of Fucp3NAc was inferred by the 1 J C,H values [10] of anomeric signals measured in a coupled 13 C NMR spectrum of OPS. The 1 H and 13 C NMR spectra of the OPS were indicative of a highly complex structure (Fig.…”

Section: Nmr Analysis Of the Opsmentioning

confidence: 99%

NMR and MS evidences for a random assembled O‐specific chain structure in the LPS of the bacterium Xanthomonas campestris pv. Vitians

Molinaro

Castro

Lanzetta

et al. 2002

Xanthomonas campestris pv. vitians is a Gram-negative plant-associated bacterium that acts as causative agent of bacterial leaf spot and headrot in lettuce. The lipopolysaccharide of this bacterium is suspected to be an important molecule for adhesion to and infection of the plants. The lipopolysaccharide has been isolated from the phenol phase and the O-specific chain characterized by compositional analysis, high field NMR and MALDI-TOF MS. It consists of a nonrepetitive branched polysaccharide with a rhamnan backbone to which Fuc3NAc is linked. The NMR and MS approach led to the characterization of the fine structure of the polymer, which is randomly assembled. The rhamnan backbone is built up of b-Rhap and a-Rhap, this last is present in one, two or three adjacent units and branched by an a-Fucp3NAc unit. This is a real case of a random constituted O-specific chain, therefore biosynthetic studies towards the comprehension of this irregular biosynthesis are needed.

“…This conclusion was proved by the l3C-l -lH-I coupling constant for unit B determined from the gated decoupling I3C nuclear magnetic resonance spectrum of bioside 4. The relatively large coupling constant, J = 174 Hz, proved that the configuration of unit B [16,17] …”

Section: Solvolysis With Hydrogen Fluoridementioning

confidence: 99%

Somatic Antigens of Pseudomonas aeruginosa

Knirel

Vinogradov

Shashkov

et al. 1983

On mild acid degradation of Pseudomonas aeruginosa 0 : 3(a),c, 0 : 3a,d,e and 0 : 3(a),d,f lipopolysaccharides 0-specific polysaccharides were isolated. The trisaccharide repeating units of 0 : 3(a),c and 0 : 3a,d,e polysaccharides contained 2-acetamido-2,6-dideoxy-~-galactose and 2,3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-D-mannuronic acid, which were identified previously as the constituents of P. aeruginosa 0 : 3 a,b and 0 : 3a,d 0-specific polysaccharides, as well as 2,3-diacetamido-2,3-dideoxy-~-guluronic acid, which has never before been found in nature. The last monosaccharide was identified without being isolated in the free state, by means of 13C nuclear magnetic resonance spectroscopy.The structures of 0 : 3(a),c and 0 : 3a,d,e polysaccharides were established by selective hydrogen fluoride solvolysis followed by modification of the trisaccharides obtained and analysis of the I3C nuclear magnetic resonance spectra at each modification stage. The polysaccharides possessed similar structures of repeating units differing from each other in the anomeric configuration of the N-acetylfucosamine residue only : +4)~ManImU-(81 -+ 4)~Gul(NAc),U(al -P 3)~FucNAc(@l-and +4)oManImU(fll + 4)~Gul(NAc),U(al4 3)~FucNAc(al-,whereThe same components were detected in the 0: 3(a),d,f polysaccharide but not in the same stoichiometric ratio; this polysaccharide possessed no regular structure.The immunochemical study of lipopolysaccharides of all five P. aeruginosa 0 : 3 serotypes showed a definite interrelation between their serological properties and structures of the corresponding 0-specific polysaccharides.In the course of systematic chemical and immunochemical studies of Pseudomonas aeruginosa lipopolysaccharides we focused our attention on the most heterogeneous serogroup 0 : 3, which includes, according to Lanyi's classification Recently we have shown that four of the five 0 : 3 serotypes possessed similar polysaccharide chains of lipopolysaccharides [4]. The chains are composed of repeating trisaccharide units containing 2-acetamido-2,6-dideoxy-~-galactose and two acidic aminosugars, namely, 2,3-( 1 -acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-~-mannuronic acid and 2,3-diacetamido-2,3-dideoxyuronic acid. The complete structures were established for the repeating units of 0 : 3a,b and 0 : 3a,d polysaccharides containing 2,3-diacetamido-2,3-dideoxy-~-mannuronic acid as the third component [5].Abbreviations. DFUCNAC, 2-acetamido-2,6-dideoxy-~-galactose; DMan(NAc)ZU, 2,3-diacetamido-2,3-dideoxy-~-mannuronic acid ; ~G u l -(NAc)2U, 2,3-diacetamido-2,3-dideoxy-~-guluronic acid; DManImU, 2,3-(l-acetyl-2-methyl-2-~midazolino-5,4)-2,3-dideoxy-~-mannuron~c acid.The present article gives an account of the evidence on the chemical structures of the repeating units of 0-specific polysaccharides P. aeruginosa 0 : 3(a),c and 0 : 3a,d,e containing 2,3-diacetamido-2,3-dideoxy-~-guluronic acid, and characterization of the irregular polysaccharide 0 : 3(a),d,f. In addition, the results of serological studies covering all th...