Analysis of the Structure and Biosynthesis of the Lipopolysaccharide Core Oligosaccharide of Pseudomonas syringae pv. tomato DC3000 |
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Authors: | Alexander Kutschera Ursula Schombel Dominik Schwudke Stefanie Ranf Nicolas Gisch |
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Affiliation: | 1.Chair of Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising-Weihenstephan, Germany;2.Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Parkallee 1-40, 23845 Borstel, Germany; (U.S.); (D.S.);3.German Center for Infection Research (DZIF), 23845 Borstel, Germany;4.Airway Research Center North, Member of the German Center for Lung Research (DZL), 23845 Borstel, Germany |
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Abstract: | Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is important for bacterial viability in general and host–pathogen interactions in particular. Negative charges at its core oligosaccharide (core-OS) contribute to membrane integrity through bridging interactions with divalent cations. The molecular structure and synthesis of the core-OS have been resolved in various bacteria including the mammalian pathogen Pseudomonas aeruginosa. A few core-OS structures of plant-associated Pseudomonas strains have been solved to date, but the genetic components of the underlying biosynthesis remained unclear. We conducted a comparative genome analysis of the core-OS gene cluster in Pseudomonas syringae pv. tomato (Pst) DC3000, a widely used model pathogen in plant–microbe interactions, within the P. syringae species complex and to other plant-associated Pseudomonas strains. Our results suggest a genetic and structural conservation of the inner core-OS but variation in outer core-OS composition within the P. syringae species complex. Structural analysis of the core-OS of Pst DC3000 shows an uncommonly high phosphorylation and presence of an O-acetylated sugar. Finally, we combined the results of our genomic survey with available structure information to estimate the core-OS composition of other Pseudomonas species. |
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Keywords: | lipopolysaccharide core oligosaccharide Pseudomonas syringae NMR spectroscopy mass spectrometry structural characterization |
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