Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 22875852Publication DOI: 10.1074/jbc.M112.401000DAJournal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: cwhitfie
uoguelph.ca
Institutions: Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
The Escherichia coli O9a and O8 O-antigen serotypes represent model systems for the ABC transporter-dependent synthesis of bacterial polysaccharides. The O9a and O8 antigens are linear mannose homopolymers containing conserved reducing termini (the primer-adaptor), a serotype-specific repeat-unit domain, and a terminator. Synthesis of these glycans occurs on the polyisoprenoid lipid-linked primer, undecaprenyl pyrophosphoryl-GlcpNAc, by two conserved mannosyltransferases, WbdC and WbdB, and a serotype-specific mannosyltransferase, WbdA. The glycan structure and pattern of conservation in the O9a and O8 mannosyltransferases are not consistent with the existing model of O9a biosynthesis. Here we establish a revised pathway using a combination of in vivo (mutant complementation) experiments and in vitro strategies with purified enzymes and synthetic acceptors. WbdC and WbdB synthesize the adaptor region, where they transfer one and two α-(1→3)-linked mannose residues, respectively. The WbdA enzymes are solely responsible for forming the repeat-unit domains of these O antigens. WbdA(O9a) has two predicted active sites and polymerizes a tetrasaccharide repeat unit containing two α-(1→3)- and two α-(1→2)-linked mannopyranose residues. In contrast, WbdA(O8) polymerizes trisaccharide repeat units containing single α-(1→3), α-(1→2) and β-(1→2)-mannopyranoses. These studies illustrate assembly systems exploiting several mannosyltransferases with flexible active sites, arranged in single and multi-domain formats
biosynthesis, Escherichia coli, O-antigens, mannosyltransferases
Structure type: polymer chemical repeating unit
Location inside paper: p.35089
Trivial name: chondroitin
Compound class: CPS
Contained glycoepitopes: IEDB_115136,IEDB_130648,IEDB_137473,IEDB_140630,IEDB_153510,IEDB_423153
Methods: 13C NMR, 1H NMR, NMR-2D, SDS-PAGE, DNA techniques, MALDI-TOF MS, NMR-1D, biochemical methods, computer analysis with CASPER, CE
Synthetic data: enzymatic
Related record ID(s): 27164, 28347, 28348, 28350
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G43702JT, GlycomeDB:
2738
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
report error