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The structure of the capsular polysaccharide from a swarming strain of pathogenic Proteus vulgaris
M M Rahman1, J Guard-Petter, K Asokan
1Complex Carbohydrate Research Center, University of Georgia, Athens 30602, USA.
Abstract:
The structure was determined for the capsular polysaccharide (CPS) isolated from a swarming strain of Proteus vulgaris, CP2-96, which was obtained from the spleen of an infected mouse. The CPS was extracted from the cell pellet by hot water, precipitated with ethanol, and further purified by gel-permeation chromatography. The structure was established by glycosyl composition and linkage analyses, and by NMR spectroscopy. The sequence of the glycosyl residues was determined by a NOESY experiment. The CPS is composed of a tetrasaccharide repeating unit with the following structure: OAc [symbol: see text] 4 -->4)-beta-D-Glcp-(1-->3)-beta-D-GalpNAc-(1-->2)-alpha-D-Glcp-(1-->4)-al pha- D-GlcpA-(1-->.
Insights
Researchers elucidated the capsular polysaccharide (CPS) structure from Proteus vulgaris CP2-96, an infectious agent. This bacterial polysaccharide comprises a unique tetrasaccharide repeating unit, crucial for understanding its biological role.
Area of Science:
- Microbiology
- Carbohydrate Chemistry
- Structural Biology
Background:
- Proteus vulgaris is a Gram-negative bacterium known for its swarming motility.
- Capsular polysaccharides (CPS) play vital roles in bacterial pathogenesis and host immune evasion.
- The specific structure of CPS from P. vulgaris strain CP2-96, isolated from an infected mouse spleen, was previously unknown.
Purpose of the Study:
- To determine the precise chemical structure of the capsular polysaccharide (CPS) from the swarming Proteus vulgaris strain CP2-96.
- To provide foundational data for understanding the interactions between this bacterial CPS and the host immune system.
Main Methods:
- Extraction of CPS from bacterial cell pellets using hot water.
- Purification of the CPS via ethanol precipitation and gel-permeation chromatography.
- Structural elucidation using comprehensive glycosyl composition and linkage analyses, Nuclear Magnetic Resonance (NMR) spectroscopy, and NOESY experiments for sequential analysis.
Main Results:
- The capsular polysaccharide (CPS) of Proteus vulgaris CP2-96 was identified as a tetrasaccharide repeating unit.
- The established structure is: OAc [symbol: see text] 4 -->4)-beta-D-Glcp-(1-->3)-beta-D-GalpNAc-(1-->2)-alpha-D-Glcp-(1-->4)-alpha-D-GlcpA-(1-->.
- The sequence of glycosyl residues was confirmed through NOESY experiments.
Conclusions:
- The complete structure of the capsular polysaccharide from Proteus vulgaris CP2-96 has been elucidated.
- This detailed structural information is essential for future studies on the immunomodulatory properties and virulence factors of this bacterial strain.