Structural analysis of a novel lipooligosaccharide (LOS) from Rhodobacter azotoformans
| Autor: | Akiyoshi Hayashi, Osamu Kanie, Makoto Hatakeyama, Yasuhiro Hidaka, Yoshiki Yamaguchi, Shinichiro Nakamura, Nobuhiro Toda, Jun Uzawa, Yoshimi Kanie |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Lipopolysaccharides
Glycan Stereochemistry 010402 general chemistry 01 natural sciences Biochemistry Bacterial cell structure Analytical Chemistry Lipid A Rhodobacter sphaeroides chemistry.chemical_compound Rhodobacter Receptor Innate immune system biology 010405 organic chemistry Chemistry Hydrolysis Organic Chemistry General Medicine Nuclear magnetic resonance spectroscopy Hydrogen-Ion Concentration biology.organism_classification Glucuronic acid 0104 chemical sciences Hydrazines biology.protein lipids (amino acids peptides and proteins) |
| Zdroj: | Carbohydrate research. 473 |
| ISSN: | 1873-426X |
| Popis: | Lipopolysaccharides (LPS) are components of the Gram-negative bacterial cell surface that stimulate the host innate immune system through the Toll-like receptor (TLR) 4–MD-2 complex. Rhodobacter sp. have been reported to produce LPS that lack endotoxic activity, and instead act as antagonists of other endotoxins. In this report, we focused on LPS, especially the lipooligosaccharide (LOS) fraction produced by Rhodobacter azotoformans that shows production of IL-8, but has an inverse correlation with IL-6 production. We analyzed their molecular structure by using mass spectrometry and nuclear magnetic resonance spectroscopy and report a novel LOS consisting of a shorter glycan structure containing glucuronic acid but not heptoses. A novel glycan structure, Glcα(1 → 4)GlcAα(1 → 4)KDOα(2 → 4)[Glcα(1 → 5)]KDOα(2 → 6)[4-phosphate]GlcNβ(1 → 6) GlcNα1-phosphate, was proposed using NMR methods. The structure was consistent with one obtained based on MS. The MS analysis further revealed the existence of structural variation caused by extension with hexoses. The acyl composition in lipid A was suggested to contain three C14 fatty acyl chains (3-OH-14:0 or 3-oxo-14:0 at N2 of GlcN-1, 3-OH-14:0 at N2 of GlcN-2, that carried another 14:1 Δ7 on its β-hydroxyl group) and two C10 fatty acyl chains (3-OH-10:0 at O3 of both GlcN), which are same as those found in lipid A from Rhodobacter sphaeroides. |
| Databáze: | OpenAIRE |
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