Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 22989876Publication DOI: 10.1074/jbc.M112.412577Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: cwhitfie
uoguelph.ca
Institutions: From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1
The Escherichia coli O9a and O8 polymannose O-polysaccharides (O-PSs) serve as model systems for the biosynthesis of bacterial polysaccharides by ATP-binding cassette transporter-dependent pathways. Both O-PSs contain a conserved primer-adaptor domain at the reducing terminus and a serotype-specific repeat unit domain. The repeat unit domain is polymerized by the serotype-specific WbdA mannosyltransferase. In serotype O9a, WbdA is a bifunctional α-(1→2)-, α-(1→3)-mannosyltransferase, and its counterpart in serotype O8 is trifunctional (α-(1→2), α-(1→3), and β-(1→2)). Little is known about the detailed structures or mechanisms of action of the WbdA polymerases, and here we establish that they are multidomain enzymes. WbdA(O9a) contains two separable and functionally active domains, whereas WbdA(O8) possesses three. In WbdC(O9a) and WbdB(O9a), substitution of the first Glu of the EX(7)E motif had detrimental effects on the enzyme activity, whereas substitution of the second had no significant effect on activity in vivo. Mutation of the Glu residues in the EX(7)E motif of the N-terminal WbdA(O9a) domain resulted in WbdA variants unable to synthesize O-PS. In contrast, mutation of the Glu residues in the motif of the C-terminal WbdA(O9a) domain generated an enzyme capable of synthesizing an altered O-PS repeat unit consisting of only α-(1→2) linkages. In vitro assays with synthetic acceptors unequivocally confirmed that the N-terminal domain of WbdA(O9a) possesses α-(1→2)-mannosyltransferase activity. Together, these studies form a framework for detailed structure-function studies on individual domains and a strategy applicable for dissection and analysis of other multidomain glycosyltransferases
biosynthesis, synthesis, serotype, Escherichia coli, O-antigens, serotype-specific, mannosyltransferases, WbdA(O9a), WbdC(O9a), WbdB(O9a)
Structure type: polymer chemical repeating unit
Location inside paper: p.38135, fig.1
Trivial name: mannose homopolysaccharide
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_115576,IEDB_130701,IEDB_136104,IEDB_140116,IEDB_141111,IEDB_141795,IEDB_141830,IEDB_143632,IEDB_144983,IEDB_152206,IEDB_153756,IEDB_164174,IEDB_164175,IEDB_164176,IEDB_164480,IEDB_174840,IEDB_241100,IEDB_76933,IEDB_983930,SB_136,SB_196,SB_197,SB_44,SB_67,SB_72
Methods: 13C NMR, 1H NMR, SDS-PAGE, MALDI-TOF MS, NMR-1D, genetic methods, biochemical methods, computer analysis with CASPER, bioinformatic analysis
Biosynthesis and genetic data: genetic data
Synthetic data: enzymatic
3D data: 3D data
Related record ID(s): 27165, 28352
NCBI Taxonomy refs (TaxIDs): 1010797Reference(s) to other database(s): GTC:G87424QV, GlycomeDB:
668, CCSD:
47538
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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