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

]

NCBI PubMed ID: 9756877
Journal NLM ID: 2985121R
Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: raetz

biochem.duke.edu
Institutions: Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, Department of Microbiology, University of Otago, Dunedin, New Zealand, and the Division of Microbiology, School of Animal and Microbiological Sciences, University of Reading, Whiteknights, United Kingdom.

The lipopolysaccharide (LPS) core of the Gram-negative bacterium Rhizobium leguminosarum is more amenable to enzymatic study than that of Escherichia coli because much of it is synthesized from readily available sugar nucleotides. The inner portion of the R. leguminosarum core contains mannose, galactose, and three 3-deoxy-D-manno-octulosonate (Kdo) residues, arranged in the order: lipid A-(Kdo)2-Man-Gal-Kdo-[O antigen]. A mannosyltransferase that uses GDP-mannose and the conserved precursor Kdo2-[4'-32P]lipid IVA (Kadrmas, J. L., Brozek, K. A., and Raetz, C. R. H. (1996) J. Biol. Chem. 271, 32119-32125) is proposed to represent a key early enzyme in R. leguminosarum core assembly. Conditions for demonstrating efficient galactosyl- and distal Kdo-transferase activities are now described using a coupled assay system that starts with GDP-mannose and Kdo2-[4'-32P]lipid IVA. As predicted, mannose incorporation precedes galactose addition, which in turn precedes distal Kdo transfer. LPS core mutants with Tn5 insertions in the genes encoding the putative galactosyltransferase (lpcA) and the distal Kdo-transferase (lpcB) are shown to be defective in the corresponding in vitro glycosylation of Kdo2-[4'-32P]lipid IVA. We have also discovered the new gene (lpcC) that encodes the mannosyltransferase. The gene is separated by several kilobase pairs from the lpcAB cluster. All three glycosyltransferases are carried on cosmid pIJ1848, which contains at least 20 kilobase pairs of R. leguminosarum DNA. Transfer of pIJ1848 into R. meliloti 1021 results in heterologous expression of all three enzymes, which are not normally present in strain 1021. Expression of the lpc genes individually behind the T7 promoter results in the production of each R. leguminosarum glycosyltransferase in E. coli membranes in a catalytically active form, demonstrating that lpcA, lpcB, and lpcC are structural genes.

core, cloning, lipopolysaccharide core, glycosyltransferases, Rhizobium leguminosarum

Structure type: oligomer
Location inside paper: p.26433, fig. 1
Aglycon: lipid A
Compound class: core oligosaccharide
Contained glycoepitopes: IEDB_130650,IEDB_130659,IEDB_130670,IEDB_136906,IEDB_137472,IEDB_140088,IEDB_140529,IEDB_141794,IEDB_142488,IEDB_144998,IEDB_146664,IEDB_151528,IEDB_190606,IEDB_2189047,IEDB_226811,IEDB_232584,IEDB_983931,SB_192,SB_7

Biosynthesis and genetic data: biosynthesis data, genetic data
Comments, role: core oligosaccharide, partial structure is shown, terminal Glc carries O-antigen

Related record ID(s): 7238
NCBI Taxonomy refs (TaxIDs): 83333
Reference(s) to other database(s): GTC:G80752ZI, GlycomeDB:27099
Show glycosyltransferases

There is only one chemically distinct structure:

O=C(O)[C@@]1(O)C[C@@H](O[C@]2(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O2)[C@@H](O[C@H]2O[C@H]([C@@H](O)CO)[C@@H](O)[C@H](O[C@H]3O[C@H]([C@@H](O)CO[C@H]4O[C@H]([C@@H](O)CO)[C@@H](O)[C@H](O)[C@@H]4O)[C@@H](O)[C@H](O[C@H]4O[C@H](CO[C@H]5O[C@H](CO)[C@H](O)[C@H](O)[C@H]5O)[C@@H](O)[C@H](O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@H]5O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@H]5O)[C@H]4O)[C@@H]3O)[C@@H]2O)[C@@H]([C@H](O)CO)O1

SVG MW SMILES 3D mol Ionize