Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 10859322Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: ISRobert
fs1.scg.man.ac.uk
Institutions: School of Biological Sciences, 1.800 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom, Department of Medical Biochemistry and Microbiology, University of Uppsala, The BioMedical Center, Box 575, S-751 23 Uppsala, Sweden.
The Escherichia coli K5 capsular polysaccharide consists of the repeat structure -4)GlcA-β(1,4)-GlcNAc-α(1- and requires the KfiA, KfiB, KfiC, and KfiD proteins for its synthesis. Previously, the KfiC protein was shown to be a β-UDP-GlcA glycosyltransferase, and KfiD was shown to be a UDP-Glc dehydrogenase. Here, we demonstrate that KfiA is an α-UDP-GlcNAc glycosyltransferase and that biosynthesis of the K5 polysaccharide involves the concerted action of the KfiA and KfiC proteins. By site-directed mutagenesis, we determined that the acidic motif of DDD, which is conserved between the C family of glycosyltransferases, is essential for the enzymatic activity of KfiA. In addition, by Western blot analysis, we determined that association of KfiA with the cytoplasmic membrane requires KfiC but not KfiB, whereas the interaction of KfiC with the cytoplasmic membrane was dependent on both KfiA and KfiB. Likewise, KfiB was only detectable in cytoplasmic membrane fractions when both KfiA and KfiC were present. These data suggest that the interaction between the KfiA, KfiB, and KfiC proteins is essential for the stable association of these proteins with the cytoplasmic membrane and the biosynthesis of the K5 polysaccharide.
biosynthesis, Escherichia coli, capsular polysaccharide, glycosyltransferase, A-protein
Structure type: polymer chemical repeating unit
Location inside paper: abstract
Trivial name: K5 polysaccharide, K-antigen, N-acetyl heparosan, heparosan (N-acetylheparosan), heparosan, heparosan (glycosaminoglycan GAG), K5 CPS, heparosan (K5-antigen), N-acetylheparosan
Compound class: CPS, EPS, K-antigen, polysaccharide
Contained glycoepitopes: IEDB_115136,IEDB_137340,IEDB_140630,IEDB_141807,IEDB_151531,IEDB_153764,IEDB_423153
Biosynthesis and genetic data: biochemical data, genetic data
Related record ID(s): 6889
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G26089XS, GlycomeDB:
656
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
report error