Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 10200954Journal NLM ID: 8712028Publisher: Blackwell Publishing
Correspondence: cwhitfie
uoguelph.ca
Institutions: Department of Microbiology, University of Guelph, Ontario, Canada
The group 1 K30 antigen from Escherichia coli (O9a:K30) is present on the cell surface as both a capsular structure composed of high- molecular-weight K30 polysaccharide and as short K30 oligosaccharides linked to lipid A-core in a lipopolysaccharide molecule (K30LPS). To determine the molecular processes that are responsible for the two forms of K antigen, the 16 kb chromosomal cps region has been characterized. This region encodes 12 gene products required for the synthesis, polymerization and translocation of the K30 antigen. The gene products include four glycosyltransferases responsible for synthesis of the K30 repeat unit; a PST (1) exporter (Wzx), required to transfer lipid-linked K30 units across the plasma membrane to the periplasmic space; and a K30-antigen polymerase (Wzy). These gene products are typical of those seen in O-antigen biosynthesis gene clusters and they interact with the lipopolysaccharide translocation pathway to express K30LPS on the cell surface. The same gene products also provide the biosynthetic intermediates for the capsule assembly pathway, although they are not in themselves sufficient for synthesis of the K30 capsule. Three additional genes, wza, wzb and wzc, encode homologues to proteins that are encoded by gene clusters involved in expression of a variety of bacterial exopolysaccharides. Mutant analysis indicates that Wza and Wzc are required for wild-type surface expression of the capsular structure but are not essential for polymerization and play no role in the translocation of K30LPS. These surface expression components provide the key feature that distinguishes the assembly systems for O antigens and capsules
Escherichia coli, capsular polysaccharide, gene cluster, glycosyltransferases, K30
Structure type: polymer chemical repeating unit
Location inside paper: Fig. 2
Compound class: K-antigen
Contained glycoepitopes: IEDB_115136,IEDB_130701,IEDB_136044,IEDB_136906,IEDB_137472,IEDB_140630,IEDB_141794,IEDB_144983,IEDB_151528,IEDB_152206,IEDB_190606,IEDB_423153,IEDB_983930,SB_165,SB_166,SB_187,SB_195,SB_44,SB_67,SB_7,SB_72,SB_88
Biosynthesis and genetic data: genetic data, biosynthetic data
NCBI Taxonomy refs (TaxIDs): 1010797Reference(s) to other database(s): GTC:G14198BB, GlycomeDB:
25521
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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