PMID:14973046
Citation |
Bausch, C, Ramsey, M and Conway, T (2004) Transcriptional organization and regulation of the L-idonic acid pathway (GntII system) in Escherichia coli.J. Bacteriol. 186:1388-97 |
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Abstract |
The genetic organization of the idn genes that encode the pathway for L-idonate catabolism was characterized. The monocistronic idnK gene is transcribed divergently from the idnDOTR genes, which were shown to form an operon. The 215-bp regulatory region between the idnK and idnD genes contains promoters in opposite orientation with transcription start sites that mapped to positions -26 and -29 with respect to the start codons. The regulatory region also contains a single putative IdnR/GntR binding site centered between the two promoters, a CRP binding site upstream of idnD, and an UP element upstream of idnK. The genes of the L-idonate pathway were shown to be under catabolite repression control. Analysis of idnD- and idnK-lacZ fusions in a nonpolar idnD mutant that is unable to interconvert L-idonate and 5-ketogluconate indicated that either compound could induce the pathway. The L-idonate pathway was first characterized as a subsidiary pathway for D-gluconate catabolism (GntII), which is induced by D-gluconate in a GntI (primary gluconate system) mutant. Here we showed that the idnK and idnD operons are induced by D-gluconate in a GntI system mutant, presumably by endogenous formation of 5-ketogluconate from D-gluconate. Thus, the regulation of the GntII system is appropriate for this pathway, which is primarily involved in L-idonate catabolism; the GntII system can be induced by D-gluconate under conditions that block the GntI system. |
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Keywords |
Electrophoresis, Gel, Two-Dimensional; Escherichia coli; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Oligonucleotide Array Sequence Analysis; Operon; Promoter Regions, Genetic; Sugar Acids; Transcription, Genetic |
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Main Points of the Paper
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Materials and Methods Used
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Phenotype Annotations
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Phenotype of | Taxon Information | Genotype Information (if known) | Condition Information | OMP ID | OMP Term Name | ECO ID | ECO Term Name | Notes | Status |
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a mutation or genetic difference within a strain |
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Mutant unable to grow on MOPS minimal medium containing L-idonate, table 5. |
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