Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Salmonella enterica [ICD11:
XN5VC 
]
NCBI PubMed ID: 16855251Publication DOI: 10.1128/JB.00306-06Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Correspondence: allan.matte
nrc-cnrc.gc.ca
Institutions: Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada, Department of Biochemistry, McGill University, Montreal, Quebec Canada
Enterobacterial common antigen (ECA) is a polysaccharide found on the outer membrane of virtually all gram-negative enteric bacteria and consists of three sugars, N-acetyl-d-glucosamine, N-acetyl-d-mannosaminuronic acid, and 4-acetamido-4,6-dideoxy-d-galactose, organized into trisaccharide repeating units having the sequence →3)-α-D-Fuc4NAc-(1→4)-β-D-ManNAcA-(1→4)-α-D-GlcNAc-(1→. While the precise function of ECA is unknown, it has been linked to the resistance of Shiga-toxin-producing Escherichia coli (STEC) O157:H7 to organic acids and the resistance of Salmonella enterica to bile salts. The final step in the synthesis of 4-acetamido-4,6-dideoxy-d-galactose, the acetyl-coenzyme A (CoA)-dependent acetylation of the 4-amino group, is carried out by TDP-fucosamine acetyltransferase (WecD). We have determined the crystal structure of WecD in apo form at a 1.95-A resolution and bound to acetyl-CoA at a 1.66-A resolution. WecD is a dimeric enzyme, with each monomer adopting the GNAT N-acetyltransferase fold, common to a number of enzymes involved in acetylation of histones, aminoglycoside antibiotics, serotonin, and sugars. The crystal structure of WecD, however, represents the first structure of a GNAT family member that acts on nucleotide sugars. Based on this cocrystal structure, we have used flexible docking to generate a WecD-bound model of the acetyl-CoA-TDP-fucosamine tetrahedral intermediate, representing the structure during acetyl transfer. Our structural data show that WecD does not possess a residue that directly functions as a catalytic base, although Tyr208 is well positioned to function as a general acid by protonating the thiolate anion of coenzyme A.
synthesis, Escherichia coli, enterobacterial common antigen, ECA, crystal structure
Structure type: polymer chemical repeating unit
Location inside paper: abstract
Trivial name: ECA, ECA LPS, enterobacterial common antigen (ECA)
Compound class: enterobacterial common antigen
Contained glycoepitopes: IEDB_141807,IEDB_151531
Methods: crystallization, two-wavelength MAD experiment
Biosynthesis and genetic data: genetic data, biosynthetic data
3D data: 3D data
Related record ID(s): 4304, 4340, 6504, 23689, 123017
NCBI Taxonomy refs (TaxIDs): 28901Reference(s) to other database(s): GTC:G63996VH, GlycomeDB:
7812
Show glycosyltransferases
There is only one chemically distinct structure:
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