Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 12621029Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: rickp
usuhs.mil
Institutions: Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA
The assembly of many bacterial cell surface polysaccharides requires the transbilayer movement of polyisoprenoid-linked saccharide intermediates across the cytoplasmic membrane. It is generally believed that transverse diffusion of glycolipid intermediates is mediated by integral membrane proteins called translocases or 'flippases.' The bacterial genes proposed to encode these translocases have been collectively designated wzx genes. The wzxE gene of Escherichia coli K- 12 has been implicated in the transbilayer movement of Fuc4NAc-ManNAcA- GlcNAc-P-P-undecaprenol (lipid III), the donor of the trisaccharide repeat unit in the biosynthesis of enterobacterial common antigen (ECA). Previous studies (Feldman, M. F., Marolda, C. L., Monteiro, M. A., Perry, M. B., Parodi, A. J., and Valvano, M. (1999) J. Biol. Chem. 274, 35129-35138) provided indirect evidence that the wzx(016) gene product of E. coli K-12 encoded a translocase capable of mediating the transbilayer movement of N-acetylglucosaminylpyrophosphorylundecaprenol (GlcNAc-P-P-Und), an early intermediate in the synthesis of ECA and many lipopolysaccharide O antigens. Therefore, genetic and biochemical studies were conducted to determine if the putative Wzx(O16) translocase was capable of mediating the transport of N- acetylglucosaminylpyrophosphorylnerol (GlcNAc-P-P-Ner), a water-soluble analogue of GlcNAc-P-P-Und. [(3)H]GlcNAc-P-P-Ner was transported into sealed, everted cytoplasmic membrane vesicles of E. coli K-12 as well as a deletion mutant lacking both the wzx(016) and wzxC genes. In contrast, [(3)H]GlcNAc-P-P-Ner was not transported into membrane vesicles prepared from a wzxE-null mutant, and metabolic radiolabeling experiments revealed the accumulation of lipid III in this mutant. The WzxE transport system exhibited substrate specificity by recognizing both a pyrophosphoryl-linked saccharide and an unsaturated alpha-isoprene unit in the carrier lipid. These results support the conclusion that the wzxE gene encodes a membrane protein involved in the transbilayer movement of lipid III in E. coli
Escherichia coli, enterobacterial common antigen, ECA, A-protein, transport
Structure type: polymer chemical repeating unit
Location inside paper: p.16535
Trivial name: ECA, ECA LPS, enterobacterial common antigen (ECA)
Compound class: enterobacterial common antigen
Contained glycoepitopes: IEDB_137340,IEDB_141807,IEDB_151531
Enzymes that release or process the structure: WecA,WecG,WecF,WzxE
Biosynthesis and genetic data: biosynthesis data, genetic data
Related record ID(s): 4304, 6504, 20045, 23689, 123017
NCBI Taxonomy refs (TaxIDs): 83333Reference(s) to other database(s): GTC:G63996VH, GlycomeDB:
7812
Show glycosyltransferases
There is only one chemically distinct structure:
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