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The ribitol-phosphate-containing lipopolysaccharide from Proteus mirabilis, strain D52. Investigations on the
Abstract:
A soluble hydrophilic lipopolysaccharide, termed lipopolysaccharide II, isolated from Proteus mirabilis, strain D52 contained N-acetylglucosamine, glucose, galactose, ribitol phosphate and ethanolamine phosphate as constituents of the O-specific polysaccharide. Periodate oxidation studies were carried out on the polymer before and after dephosphorylation with hydrofluoric acid and on oligosaccharides derived from the polymer by partial acid hydrolysis. The results obtained indicate that the polysaccharide chain consists of the chemical repeating unit Gal-1,3(4)-GlcNAc-1,3-Glc-1,3-GlcNAc-, where GlcNAc stands for N-acetylglucosamine. Whereas the galactose residue is substituted at C-3 by ribitol phosphate, the glucose is substituted by ethanolamine phosphate at C-6.
Insights
Researchers characterized lipopolysaccharide II from Proteus mirabilis, revealing its O-specific polysaccharide structure. The study identified N-acetylglucosamine, glucose, and galactose as key components, detailing their linkage and phosphate substitutions.
Area of Science:
- Microbiology
- Carbohydrate Chemistry
- Structural Biology
Background:
- Lipopolysaccharides (LPS) are crucial components of Gram-negative bacterial outer membranes.
- Proteus mirabilis LPS structure is important for understanding bacterial pathogenesis and host interactions.
- Lipopolysaccharide II (LPS II) from P. mirabilis strain D52 was previously isolated and characterized as soluble and hydrophilic.
Purpose of the Study:
- To elucidate the detailed chemical structure of the O-specific polysaccharide of LPS II from Proteus mirabilis.
- To determine the repeating unit and the positions of phosphate substitutions within the polysaccharide chain.
Main Methods:
- Periodate oxidation studies were performed on the intact LPS II polymer.
- Dephosphorylation using hydrofluoric acid was conducted prior to further analysis.
- Partial acid hydrolysis was used to derive oligosaccharides for structural determination.
Main Results:
- The O-specific polysaccharide of LPS II contains N-acetylglucosamine (GlcNAc), glucose (Glc), and galactose (Gal).
- Periodate oxidation and hydrolysis data indicated a repeating unit with the structure Gal-1,3(4)-GlcNAc-1,3-Glc-1,3-GlcNAc-.
- Ribitol phosphate substituted the galactose residue at C-3, and ethanolamine phosphate substituted the glucose residue at C-6.
Conclusions:
- The study successfully determined the chemical repeating unit of the O-specific polysaccharide of Proteus mirabilis LPS II.
- The specific locations of ribitol phosphate and ethanolamine phosphate substitutions were identified, providing insights into LPS II structure-function relationships.