The kdgRKAT operon of Bacillus subtilis:detection of the transcript and regulation by the kdgR and ccpA genes

Abstract

Transcription of a new catabolic operon in Bacillus subtilis, involved in the late stages of galacturonic acid utilization, has been studied. The operon consists of four genes: kdgR, encoding the putative regulator protein; kdgK, encoding 2-keto-3-deoxyg I uconate kinase ; kdgA, encoding 2-keto-3-deoxyg luconate-6-phosphate aldolase; and kdgr, encoding a transporter. These four genes are organized in one transcriptional unit and map at 198" of the B. subtik chromosome. Primer extension experiments and Northern blot analysis show that an active &-dependent promoter precedes kdgR and transcription is terminated at the putative pindependent terminator downstream of kdgr. The operon is negatively regulated by the kdgR and ccpA gene products, which belong t o the Lac1 family of transcription regulators. The expression of the genes in this operon can be induced by galacturonate and strongly repressed when glucose is present in the growth medium. Knockout mutations in genes kdgR and ccpA remove, respectively, the effects of galacturonate and glucose on the transcription of this operon.

The Bacillus subtilis yqjI Gene Encodes the NADP + -Dependent 6-P-Gluconate Dehydrogenase in the Pentose Phosphate Pathway

“…In B. subtilis, we could exclude the possibility that there was a functional Entner-Doudoroff pathway under the conditions investigated because we never observed [1-13 C]alanine in experiments with [1-13 C]glucose (15), even in the yqjI mutant. Although B. subtilis contains a homologue of the second pathway enzyme, 2-keto-3-deoxygluconate-6-P aldolase (37), the absence of a 6-P-gluconate dehydratase homologue and our results suggest that the pathway does not exist in B. subtilis.…”

Six putative two-component regulatory systems isolated from Lactococcus lactis subsp. cremoris MG1363 The GenBank accession numbers for the sequences of the six 2CSs and surrounding ORFs determined in this work are AF172649, AF176556, AF178425, AF172650, AF176557 and AF176809 for systems A–F, respectively.

“…Hybridization probes derived from each 2CS [internal 300 bp fragments of each RR-encoding gene cloned in pBluescript SK(k)] were radiolabelled with [α-$#P]dCTP by random priming (Roche Diagnostics). Primer extension was performed by annealing 10 pmol 5h-end γ-$#P-labelled synthetic 18-mer oligonucleotides to 50 µg of RNA as described by Pujic et al (1998). Sequence ladders were produced using the same primers as the primer extension product with the aid of the Sequenase sequencing kit (version 2.0) (US Biochemical).…”

Carbon Catabolite Control of the Metabolic Network inBacillus subtilis

“…The operons involved in the catabolism of secondary carbon sources are as follows (the carbon sources in parentheses): gntRKPZ (gluconate), 16,35,36) xylAB (xylose), 9) iolABCDEFGHIJ (myo-inositol), 40,41,102) trePAR (trehalose), 25,47,103) galKT (galactose), 25) glpFK (glycerol), 33) glvARC (6-P--glucoside), 34) bglPH ( -glucoside), 26,27) yjlBCD-uxaC-yjmBCD-uxuA-yjmFexuTR-uxaBA (hexuronate), 25,48) xynPB ( -xyloside), 65) yxjC-scoAE-bdh ( -hydroxybutyrate), 25,49) ara-ABDLMNPQ-abfA (arabinose) 24,52,53) and abnA xsa (arabinose), 50) kdgRKAT (hexuronate), 25,42) and kduID (galacturonate). 43) The yxkF-msmX operon probably involved in the transport of unknown sugars has been found to be under CcpA-mediated CCR.…”