title: Region 2 of the Escherichia coli K5 capsule gene cluster encoding proteins for the biosynthesis of the K5 polysaccharide.
abstract: The nucleotide sequence of region 2 of the Escherichia coli K5 capsule gene cluster has been determined. This region, essential for the biosynthesis of the K5 polysaccharide, contained four genes, termed kfiA-D. The G + C ratio was 33.4%, which was lower than the typical G + C ratio for E. coli and that of the flanking regions 1 and 3 in the K5 capsule gene cluster. Three major RNA transcripts were detected within region 2 by Northern blotting and three promoters located by transcript mapping. Promoter activity was confirmed by promoter-probe analysis. The predicted amino acid sequence of KfiC had homology to a number of glycosyl transferase enzymes and overexpression of the KfiC gene resulted in increased K5 transferase activity. The predicted amino acid sequence of KfiD had homology to a number of NAD-dependent dehydrogenase enzymes and was demonstrated to be a UDP-glucose dehydrogenase that catalyses the information of UDP-glucuronic acid from UDP-glucose.
authors.affiliation: Department of Microbiology and Immunology, University of Leicester, UK.
authors.forename: C
authors.initials: C
authors.lastname: Petit
authors.forename: G P
authors.initials: GP
authors.lastname: Rigg
authors.forename: C
authors.initials: C
authors.lastname: Pazzani
authors.forename: A
authors.initials: A
authors.lastname: Smith
authors.forename: V
authors.initials: V
authors.lastname: Sieberth
authors.forename: M
authors.initials: M
authors.lastname: Stevens
authors.forename: G
authors.initials: G
authors.lastname: Boulnois
authors.forename: K
authors.initials: K
authors.lastname: Jann
authors.forename: I S
authors.initials: IS
authors.lastname: Roberts
mesh_terms: D000595:Amino Acid Sequence; D016667:Bacterial Capsules / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001482:Base Composition; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D016695:Glycosyltransferases; D008969:Molecular Sequence Data; D005810:Multigene Family; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D011135:Polysaccharides, Bacterial; D012333:RNA, Messenger; C097522:KfiD protein, E coli; D014533:Uridine Diphosphate Glucose Dehydrogenase; D016695:Glycosyltransferases; C097521:KfiC protein, E coli