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

]

The structure was elucidated in this paper
NCBI PubMed ID: 20795687
Journal NLM ID: 0370623
Publisher: American Chemical Society
Correspondence: raetz

biochem.duke.edu
Institutions: Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA

The lipid A moiety of Escherichia coli lipopolysaccharide is a hexaacylated disaccharide of glucosamine that is phosphorylated at the 1 and 4' positions. Expression of the Francisella novicida lipid A 1-phosphatase FnLpxE in E. coli results in dephosphorylation of the lipid A proximal unit. Coexpression of FnLpxE and the Rhizobium leguminosarum lipid A oxidase RlLpxQ in E. coli converts much of the proximal glucosamine to 2-amino-2-deoxygluconate. Expression of the F. novicida lipid A 4'-phosphatase FnLpxF in wild-type E. coli has no effect because FnLpxF cannot dephosphorylate hexaacylated lipid A. However, expression of FnLpxF in E. coli lpxM mutants, which synthesize pentaacylated lipid A lacking the secondary 3'-myristate chain, causes extensive 4'-dephosphorylation. Coexpression of FnLpxE and FnLpxF in lpxM mutants results in massive accumulation of lipid A species lacking both phosphate groups, and introduction of RlLpxQ generates phosphate-free lipid A variants containing 2-amino-2-deoxygluconate. The proposed lipid A structures were confirmed by electrospray ionization mass spectrometry. Strains with 4'-dephosphorylated lipid A display increased polymyxin resistance. Heptose-deficient mutants of E. coli lacking both the 1- and 4'-phosphate moieties are viable on plates but sensitive to CaCl(2). Our methods for reengineering lipid A structure may be useful for generating novel vaccines and adjuvants.

lipopolysaccharides, Escherichia coli, Rhizobia, mass spectrometry, lipid A structure, polymyxin

Structure type: oligomer ; 1012.55 [M-2H]2-
Location inside paper: p.8327, fig.2, Kdo2-lipid A, p.8333, fig.6A
Compound class: lipid A
Contained glycoepitopes: IEDB_130650,IEDB_130659,IEDB_135394,IEDB_135515,IEDB_141807,IEDB_150908,IEDB_151531,IEDB_534864

Methods: DNA techniques, ESI-MS, mild acid hydrolysis, genetic methods, enzymatic modification
Comments, role: lipid A of mutant strain E. coli SR8209/pWSK29 LPS

Related record ID(s): 31140, 31185, 31186, 31187, 31188, 31189, 31191, 31192, 31193, 31194, 31195, 31196
NCBI Taxonomy refs (TaxIDs): 562
Show glycosyltransferases

There is only one chemically distinct structure:

CCCCCCCCCCCC(=O)O[C@H](CCCCCCCCCCC)CC(=O)N[C@H]1[C@H](OC[C@H]2O[C@H](OP(=O)(O)O)[C@H](NC(=O)C[C@H](O)CCCCCCCCCCC)[C@@H](OC(=O)C[C@H](O)CCCCCCCCCCC)[C@@H]2O)O[C@H](CO[C@]2(C(=O)O)C[C@@H](O[C@]3(C(=O)O)C[C@@H](O)[C@@H](O)[C@@H]([C@H](O)CO)O3)[C@@H](O)[C@@H]([C@H](O)CO)O2)[C@@H](OP(=O)(O)O)[C@@H]1OC(=O)C[C@H](O)CCCCCCCCCCC

SVG MW SMILES 3D mol Ionize