Characterization of a polysaccharide component of lipopolysaccharide from Pseudomonas aeruginosa IID 1008 (ATCC 27584) as D‐rhamnan

Abstract

Structural studies were carried out on a rhamnose‐rich polysaccharide isolated from the O‐polysaccharide fraction of lipopolysaccharide in Pseudomonas aeruginosa IID 1008 (ATCC 27584) after destruction of the major O‐specific chain by alkaline treatment. The isolated polysaccharide contained rhamnose, 3‐O‐methyl‐6‐deoxyhexose, glucose, xylose, alanine, galactosamine and phosphorus in a molar ratio of 67:6.9:4.3:2.1:1.1:1.0:4.1. Data from analysis involving Smith degradation, methylation, 1H‐NMR spectroscopy and optical rotation measurement showed that the polysaccharide was built up of three moieties, a rhamnan chain composed of about 70 D‐rhamnose residues, the core chain and an oligosaccharide chain comprising 3‐O‐methyl‐6‐deoxyhexose, xylose, rhamnose and probably glucose. The repeating unit of the rhamnan chain was indicated to have the following structure: →3)D‐Rha(α1 → 3)D‐Rha(α1 → 2)D‐Rha(α1 →. This structure is identical with that proposed previously for the repeating unit of the side chain of lipopolysaccharide from plant pathogenic bacteria Pseudomonas syringae pv. morsprunorum C28 [Smith, A. R. W., Zamze, S. E., Munro, S. M., Carter, K. J. and Hignett, R. C. (1985) Eur. J. Biochem. 149, 73–78].

Structural studies on the polysaccharide portion of "A-band" lipopolysaccharide from a mutant (AK1401) of Pseudomonas aeruginosa strain PAO1

“…Rhamnans have been previously reported to be present in lipopolysaccharide preparations from Pseudomonas aeruginosa (11,12), as well as P. syringae (16,17) and P. cepacia (18). Those from P. aeruginosa occur as minor components of the LPS, and their presence is seen only after the major 0-antigens are selectively hydrolyzed with acid or base; the rhamnans found in the other species are in fact the side chains of the principal LPS's.…”

“…Identities were confirmed by coinjection of standard samples, except for the 3-0-methylhexose, which was identified from its mass spectrum alone, and which was distinguished from a 4 -0 -methylhexose by GC-MS analysis of the alditol-dl acetate^.^ The minor monosaccharides found for the A-PS derived from AK1401 are slightly different from those found in other rhamnanbased polysaccharides of Pseudomonas. For example, Yokota et al (11) found that the polysaccharide from P . aeruginosa ATCC 27584 contained rhamnose, a 6-deoxy-3-0-methylhex6~h e sample of alditol-dl acetates was prepared by Dr. A. Sen (Queen's University); the GC-MS data were acquired by J. Peltier (McMaster University).…”

Identification of Two GDP-6-deoxy-d-lyxo-4-hexulose Reductases Synthesizing GDP-d-rhamnose in Aneurinibacillus thermoaerophilus L420-91T

“…It has been proposed that comparable pathways are used for the biosynthesis of these similar glycoconjugates (3). D-Rhamnose is a rare sugar that is also constituent of the LPS of plant pathogens like Xanthomonas campestris (7), Pseudomonas syringae (8) and of human pathogens, most importantly Pseudomonas aeruginosa (9), Burkholderia cepacia (10), Campylobacter fetus (11), and Helicobacter pylori (12). Recently, a biosynthetic pathway for the nucleotide-activated form of D-rhamnose has been proposed (13).…”

Smith-degradative studies on the polysaccharide portion of A-band lipopolysaccharide from a mutant (AK1401) of Pseudomonas aeruginosa strain PAO1

“…The reaction of 1,3-di-0-benzylglycerol (9) (13) with 3-0-acetyl-2,4-di-0-benzyl-a-D-rhamnopyranosyl chloride (10) (14) was performed in the presence of silver triflate and powdered, 4 A molecular sieves at -10°C to afford the rhamnopyranoside 11 in 50% yield. 0-Deacetylation of 11 with 0.5% sodium methoxide in methanol at room temperature for 4 h gave 0-(2',4'-di-0-benzyl-a-D-rhamnopyranosy1)-(lf+2)-1,3-di-0-benzylglycerol (12), a glycosyl acceptor, that was in turn glycosylated with 10, again by use of silver triflate and powdered, 4 A molecular sieves, to give the disaccharideglycerol conjugate 13.…”