Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
The structure was elucidated in this paperNCBI PubMed ID: 17163638Journal NLM ID: 101282906Publisher: Washington, DC: American Chemical Society
Correspondence: rww
umich.edu
Institutions: Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109-1065, USA, Department of Immunochemistry and Biochemical Microbiology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Parkallee 10, D-23845 Borstel, Germany
Gram-negative bacteria possess an asymmetric lipid bilayer surrounding the cell wall, the outer membrane (OM). The OM inner leaflet is primarily composed of various glycerophospholipids, whereas the outer leaflet predominantly contains the unique amphiphilic macromolecule, lipopolysaccharide (LPS or endotoxin). The majority of all gram-negative bacteria elaborate LPS containing at least one 2-keto 3-deoxy-D-manno-octulosonate (Kdo) molecule. The minimal LPS structure required for growth of Escherichia coli has long been recognized as two Kdo residues attached to lipid A, inextricably linking viability to toxicity. Here we report the construction and characterization of the nonconditional E. coli K-12 suppressor strain KPM22 that lacks Kdo and is viable despite predominantly elaborating the endotoxically inactive LPS precursor lipid IV(A). Our results challenge the established E. coli Kdo2-lipid A dogma, indicating that the previously observed and well-documented dependence of cell viability on the synthesis of Kdo stems from a lethal pleiotropy precipitated after the depletion of the carbohydrate, rather than an inherent need for the Kdo molecule itself as an indispensable structural component of the OM LPS layer. Inclusion of the inner membrane LPS transporter MsbA on a multicopy plasmid partially suppresses the lethal ∆Kdo phenotype directly in the auxotrophic parent strain, suggesting increased rates of nonglycosylated lipid A transport can, in part, compensate for Kdo depletion. The unprecedented nature of a lipid IV(A) OM redefines the requisite LPS structure for viability in E. coli
Lipopolysaccharide, Escherichia coli, lipid A, gram negative bacteria
Structure type: oligomer
Location inside paper: p.36, fig. 3b
Trivial name: lipid IVA
Compound class: LOS, lipid A, glycolipid
Contained glycoepitopes: IEDB_135394,IEDB_135515,IEDB_141807,IEDB_151531,IEDB_176772,IEDB_534864
Methods: SDS-PAGE, ESI-ICR-MS, composition analysis, genetic methods, electron microscopy, immunoblotting
Biosynthesis and genetic data: biochemical data, genetic data
Comments, role: Kdo-negative mutant
Related record ID(s): 31258
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GlycomeDB:
7396
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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