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Taxonomic group: bacteria / Proteobacteria (Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11: XN6P4

]

NCBI PubMed ID: 15929980
Journal NLM ID: 2985121R
Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: cwhitfie

uoguelph.ca
Institutions: Department of Molecular and Cellular Biology, University of Guelph, Guelph Ontario N1G 2W1, Canada, Biological Sciences, National Research Council, Ottawa, Ontario K1A 0R6, Canada

In most members of the Enterobacteriaceae, including Escherichia coli and Salmonella, the lipopolysaccharide core oligosaccharide backbone is modified by phosphoryl groups. The negative charges provided by these residues are important in maintaining the barrier function of the outer membrane. Mutants lacking the core heptose region and the phosphate residues display pleiotrophic defects collectively known as the deep-rough phenotype, characterized by changes in outer membrane structure and function. Klebsiella pneumoniae lacks phosphoryl residues in its core, but instead contains galacturonic acid. The goal of this study was to determine the contribution of galacturonic acid as a critical source of negative charge. A mutant was created lacking all galacturonic acid by targeting UDP-galacturonic acid precursor synthesis through a mutation in gla(KP). Gla(KP) is a K. pneumoniae UDP-galacturonic acid C4 epimerase providing UDP-galacturonic acid for core synthesis. The gla(KP) gene was inactivated and the structure of the mutant lipopolysaccharide was determined by mass spectrometry. The mutant displayed characteristics of a deep-rough phenotype, exhibiting a hypersensitivity to hydrophobic compounds and polymyxin B, an altered outer membrane profile, and the release of the periplasmic enzyme beta-lactamase. These results indicate that the negative charge provided by the carboxyl groups of galacturonic acid do play an equivalent role to the core oligosaccharide phosphate residues in establishing outer membrane integrity in E. coli and Salmonella.

role, acid, Klebsiella, galacturonic acid, membrane, outer membrane, PDF, stability

Structure type: oligomer
Location inside paper: p.27605
Aglycon: lipid A
Compound class: core oligosaccharide
Contained glycoepitopes: IEDB_120354,IEDB_123890,IEDB_130650,IEDB_130659,IEDB_130670,IEDB_133751,IEDB_136105,IEDB_136906,IEDB_137472,IEDB_140088,IEDB_140529,IEDB_141794,IEDB_142488,IEDB_144998,IEDB_146664,IEDB_150901,IEDB_151528,IEDB_190606,IEDB_2189047,IEDB_225177,IEDB_226811,IEDB_232584,IEDB_885823,IEDB_983931,SB_192,SB_7

Methods: genetic methods
Biosynthesis and genetic data: genetic data, biosynthetic data

Related record ID(s): 10041, 10225, 10226, 10227, 10228, 10229
NCBI Taxonomy refs (TaxIDs): 83333
Reference(s) to other database(s): GTC:G81217RA
Show glycosyltransferases

There is only one chemically distinct structure:

C[C@@H]1O[C@@H](O[C@H]2[C@@H]([C@@H](CO)OP(=O)(O)OCCN)O[C@@](O[C@@H]3C[C@](O)(C(=O)O)O[C@H]([C@H](O)CO)[C@@H]3O[C@H]3O[C@H]([C@@H](O)CO)[C@@H](OP(=O)(O)O)[C@H](O[C@H]4O[C@H]([C@@H](O)CO[C@H]5O[C@H]([C@@H](O)CO)[C@@H](O)[C@H](O)[C@@H]5O)[C@@H](OP(=O)(O)O)[C@H](O[C@H]5O[C@H](CO[C@H]6O[C@H](CO)[C@H](O)[C@H](O)[C@H]6O)[C@@H](O)[C@H](O[C@H]6O[C@H](CO)[C@@H](O)[C@H](O)[C@H]6O[C@H]6O[C@H](CO)[C@@H](O[C@H]7O[C@H]([C@@H](O)CO)[C@@H](O)[C@H](O)[C@@H]7O)[C@H](O)[C@H]6O)[C@H]5O)[C@@H]4O)[C@@H]3O)(C(=O)O)C[C@H]2O[C@]2(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O2)[C@H](O)[C@H](O)[C@H]1O

SVG MW SMILES 3D mol Ionize