Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 8397188Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Institutions: Max-Planck-Institut fur Immunbiologie, Freiburg, Germany.
The gene cluster of the capsular K5 polysaccharide, a representative of group II capsular antigens of Escherichia coli, has been cloned previously, and three regions responsible for polymerization and surface expression have been defined (I.S. Roberts, R. Mountford, R. Hodge, K. B. Jann, and G. J. Boulnois, J. Bacteriol. 170:1305-1330, 1988). Region 1 has now been sequenced, and five open reading frames (kpsEDUCS) have been defined (C. Pazzani, C. Rosenow, G. J. Boulnois, D. Bronner, K. Jann, and I. S. Roberts, J. Bacteriol. 175:5978-5983, 1993). In this study, we characterized region 1 mutants by immunoelectron microscopy, membrane-associated polymerization activity, cytoplasmic CMP-2-keto-3-deoxyoctonate (KDO) synthetase activity, and chemical analysis of their K5 polysaccharides. Certain mutations within region 1 not only effected polysaccharide transport (lack of region 1 gene products) but also impaired the polymerization capacity of the respective membranes, reflected in reduced amounts of polysaccharide but not in its chain length. KDO and phosphatidic acid (phosphatidyl-KDO) substitution was found with extracellular and periplasmic polysaccharide and not with cytoplasmic polysaccharide. This and the fact that the K5 polysaccharide is formed in a kpsU mutant (defective in capsule-specific K-CMP-KDO synthetase) showed that CMP-KDO is engaged not in initiation of polymerization but in translocation of the polysaccharide.
antigen, expression, gene, capsular, polysaccharide, analysis, capsular polysaccharide, polysaccharides, chain, group, Escherichia, Escherichia coli, acid, antigens, cluster, gene cluster, mutant, mutants, activity, region, biochemical, reduced, surface, mutation, synthetase, extracellular, transport, capacity, chain length, Microscopy, polymerization, electron microscopy, D
Structure type: polymer chemical repeating unit
Location inside paper: p.5984
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: EPS, K-antigen, CPS, polysaccharide
Contained glycoepitopes: IEDB_115136,IEDB_140630,IEDB_141807,IEDB_151531,IEDB_153764,IEDB_423153
Methods: genetic methods, biochemical methods, microscopy
Biosynthesis and genetic data: genetic data
Synthetic data: enzymatic
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G26089XS, GlycomeDB:
656
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There is only one chemically distinct structure:
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