Clarke BR, Cuthbertson L, Whitfield C Nonreducing terminal modifications determine the chain length of polymannose O antigens of Escherichia coli and couple chain termination to polymer export via an ATP-binding cassette transporter Journal of Biological Chemistry279(34) (2004)
35709-35718
NCBI PubMed ID:15184370 Publication DOI:10.1074/jbc.M404738200 Journal NLM ID:2985121R Publisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology Correspondence: cwhitfieuoguelph.ca Institutions: Department of Microbiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
The chain length of bacterial lipopolysaccharide O antigens is regulated to give a modal distribution that is critical for pathogenesis. This paper describes the process of chain length determination in the ATP-binding cassette (ABC) transporter-dependent pathway, a pathway that is widespread among Gram-negative bacteria. Escherichia coli O8 and O9/O9a polymannans are synthesized in the cytoplasm, and an ABC transporter exports the nascent polymer across the inner membrane prior to completion of the LPS molecule. The polymannan O antigens have nonreducing terminal methyl groups. The 3-O-methyl group in serotype O8 is transferred from S-adenosylmethionine by the WbdD(O8) enzyme, and this modification terminates polymerization. Methyl groups are added to the O9a polymannan in a reaction dependent on preceding phosphorylation. The bifunctional WbdD(O9a) catalyzes both reactions, but only the kinase activity controls chain length. Chain termination occurs in a mutant lacking the ABC transporter, indicating that it precedes export. An E. coli wbdD(O9a) mutant accumulated O9a polymannan in the cytoplasm, indicating that WbdD activity coordinates polymannan chain termination with export across the inner membrane.
Methods: serological methods, genetic methods, biochemical methods, immunofluorescence microscopy Biosynthesis and genetic data: genetic data, biochemical data
Related record ID(s): 883, 5762, 7199, 10527, 20624, 25285, 25286, 25287 NCBI Taxonomy refs (TaxIDs):1010797, 573 Reference(s) to other database(s): GTC:G12878ZR, GlycomeDB:25318 Show glycosyltransferases
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