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Analysis of the lipopolysaccharide of Pseudomonas maltophilia 555
J L Di Fabio1, M B Perry, D R Bundle
1Division of Biological Sciences, National Research Council, Ottawa, Ont., Canada.
Abstract:
The phenol phase soluble lipopolysaccharide of Pseudomonas maltophilia strain 555, obtained from cells by the hot aqueous phenol method, was of the smooth type. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, hydrolysis, methylation, and 13C and 1H nuclear magnetic resonance analyses showed that this lipopolysaccharide has an O-chain polysaccharide composed of a repeating pentasaccharide unit, containing D-rhamnose (D-Rha, one part), 3-acetamido-3,6-dideoxy-D-galactose (D-Fuc3NAc, one part), and 4-acetamido-4,6-dideoxy-D-mannose (D-Rha4NAc, three parts) and having the structure (formula; see text) The serological cross-reactions between P. maltophilia 555 and Brucella species can now be related to the occurrence of N-acyl derivatives of 4-amino-4,6-dideoxy-D-mannopyranosyl residues in the O-chains of their respective lipopolysaccharide components.
Insights
Researchers characterized the lipopolysaccharide from Pseudomonas maltophilia strain 555, revealing an O-chain polysaccharide with a unique repeating pentasaccharide unit. This finding helps explain serological cross-reactions with Brucella species.
Area of Science:
- Microbiology
- Carbohydrate Chemistry
- Immunology
Background:
- Lipopolysaccharides (LPS) are crucial components of Gram-negative bacterial outer membranes.
- Pseudomonas maltophilia (now Burkholderia mallei) exhibits serological similarities with Brucella species, suggesting shared antigenic structures.
- Understanding LPS structure is vital for bacterial identification and understanding host-pathogen interactions.
Purpose of the Study:
- To elucidate the detailed chemical structure of the O-chain polysaccharide of lipopolysaccharide from Pseudomonas maltophilia strain 555.
- To correlate the determined LPS structure with observed serological cross-reactivity between P. maltophilia and Brucella species.
Main Methods:
- Extraction of lipopolysaccharide using the hot aqueous phenol method.
- Structural analysis employing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), hydrolysis, methylation, and nuclear magnetic resonance (NMR) spectroscopy (13C and 1H).
Main Results:
- The lipopolysaccharide was of the smooth type.
- The O-chain polysaccharide consists of a repeating pentasaccharide unit: one D-rhamnose, one 3-acetamido-3,6-dideoxy-D-galactose, and three 4-acetamido-4,6-dideoxy-D-mannose units.
- The structure of the repeating unit was determined.
Conclusions:
- The detailed structure of the P. maltophilia 555 LPS O-chain has been established.
- The presence of N-acyl derivatives of 4-amino-4,6-dideoxy-D-mannopyranosyl residues in the O-chains explains the serological cross-reactions with Brucella species.