title: Regulation of hexuronate utilization in Bacillus subtilis.
abstract: We have identified a locus essential for galacturonate utilization in Bacillus subtilis. Genes homologous to Escherichia coli and Erwinia chrysanthemi glucuronate and galacturonate metabolic genes were found in a cluster consisting of 10 open reading frames (ORFs) in the B. subtilis chromosome. A mutant of B. subtilis containing a replacement of the second and third ORFs was unable to grow with galacturonate as its primary carbon source. Galacturonate induced expression from a sigmaA-dependent promoter, exuP1, located upstream from the first ORF. The eighth ORF in this cluster (the exu locus) encodes a LacI and GalR homolog that negatively regulated expression from exuP1. A 26-bp inverted repeat sequence centered 15 bp downstream from the exuP1 start point of transcription acted in cis to negatively regulate expression from exuP1 under noninducing conditions. Expression from the exuP1 promoter was repressed by high levels of glucose, which is probably mediated by CcpA (catabolite control protein A). A sigmaE-dependent promoter, exuP2, was localized between the second and third ORFs and was active during sporulation.
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Mekjian
authors.forename: E M
authors.initials: EM
authors.lastname: Bryan
authors.forename: B W
authors.initials: BW
authors.lastname: Beall
authors.forename: C P
authors.initials: CP
authors.lastname: Moran
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000235:genetics; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016974:Dickeya chrysanthemi / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D005838:Genotype; D005965:Glucuronates / Q000378:metabolism*; D020723:Glucuronic Acid; D006603:Hexuronic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004269:DNA, Bacterial; D005965:Glucuronates; D006603:Hexuronic Acids; C007819:galacturonic acid; D020723:Glucuronic Acid; D019747:Aldose-Ketose Isomerases; C020589:glucuronate isomerase