Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 11943778Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: kimata
aichi-med-u.ac.jp
Institutions: Institute for Molecular Science of Medicine, Aichi Medical University, Yazako, Nagakute, Aichi 480-1195, Central Research Laboratories, Seikagaku Corporation, Tateno, Higashiyamato-shi, Tokyo 207-0021, Department of Chemistry, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo 060-0810, Japan
Escherichia coli strain K4 produces the K4 antigen, a capsule polysaccharide consisting of a chondroitin backbone [GlcUA β(1-3)- GalNAc β(1-4)]n_ to which β-fructose is linked at position C-3 of the GlcUA residue. Here, we molecularly cloned region 2 of the K4 capsular gene cluster essential for biosynthesis of the polysaccharide, and further identified a gene encoding a bifunctional glycosyltransferase that polymerizes the chondroitin backbone. The enzyme, containing two conserved glycosyltransferase sites, showed 59% and 61% identity at the amino acid level to class 2 hyaluronan synthase and chondroitin synthase from Pasteurella multocida, respectively. The soluble enzyme expressed in a bacterial expression system transferred GalNAc and GlcUA residues alternately, and polymerized the chondroitin chain up to a molecular mass of 20 kDa when chondroitin sulfate (CS) hexasaccharide was used as an acceptor. The enzyme exhibited apparent km values for UDP-GlcUA and UDP-GalNAc of 3.44 mM and 31.6 mM, respectively, and absolutely required acceptors of CS polymers and oligo-saccharides at least longer than a tetrasaccharide. In addition, chondroitin polymers and oligosaccharides, and hyaluronan polymers and oligosaccharides served as acceptors for chondroitin polymerization, but dermatan sulfate and heparin did not. These results may lead to elucidation of the mechanism for chondroitin chain synthesis in both microorganisms and mammals
biosynthesis, synthesis, antigen, oligosaccharide, tetrasaccharide, hexasaccharide, expression, gene, Bacterial, strain, capsular, characterization, polysaccharide, chain, linked, molecular, polymer, Escherichia, Escherichia coli, acid, cloning, conserved, Oligosaccharides, class, level, cluster, gene cluster, region, position, mechanism, lead, medicine, backbone, elucidation, capsule, enzyme, glycosyltransferase, molecular mass, amino, chondroitin, site, acceptor, cloned, heparin, amino acid, capsule polysaccharide, Polymers, Pasteurella multocida, soluble, medical, synthase, chondroitin sulfate, Dermatan Sulfate, hyaluronan, mammal, Mammals, Pasteurella, polymerization, sulfate
Structure type: polymer chemical repeating unit
Location inside paper: abstract
Compound class: CPS, K-antigen
Contained glycoepitopes: IEDB_115136,IEDB_130648,IEDB_137473,IEDB_140630,IEDB_153510,IEDB_423153
Biosynthesis and genetic data: biosynthesis data, genetic data
Related record ID(s): 5543, 6896, 8617, 8901, 9201
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G09906MP, GlycomeDB:
16774
Show glycosyltransferases
There is only one chemically distinct structure:
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