Sigma factors and promoters in Corynebacterium glutamicum

Pátek, Miroslav; Nešvera, Jan

doi:10.1016/j.jbiotec.2011.01.017

Cited by 111 publications

(123 citation statements)

References 108 publications

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“…In three independent experiments, TS malP was found to be the A residue of the annotated ATG start codon. Upstream of TS malP , we found the motif TAAACT, which is identical in four of six bases to the Ϫ10 consensus motif (TAC/ TAAT) described for corynebacteria and which is identical to the Ϫ10 motif described for the promoters of ppmA, pta (P1), clgR (P2), clpB (P2), and ilvN (68,69). To confirm the presence of a malP-specific promoter and to investigate transcriptional regulation of the malP gene, a transcriptional fusion between the putative malP promoter region and the promoterless chloramphenicol acetyltransferase (CAT) gene was constructed in the promoter probe vector pET2.…”

Section: Resultssupporting

confidence: 62%

The α-Glucan Phosphorylase MalP of Corynebacterium glutamicum Is Subject to Transcriptional Regulation and Competitive Inhibition by ADP-Glucose

et al. 2015

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ABSTRACT␣-Glucan phosphorylases contribute to degradation of glycogen and maltodextrins formed in the course of maltose metabolism in bacteria. Accordingly, bacterial ␣-glucan phosphorylases are classified as either glycogen or maltodextrin phosphorylase, GlgP or MalP, respectively. GlgP and MalP enzymes follow the same catalytic mechanism, and thus their substrate spectra overlap; however, they differ in their regulation: GlgP genes are constitutively expressed and the enzymes are controlled on the activity level, whereas expression of MalP genes are transcriptionally controlled in response to the carbon source used for cultivation. We characterize here the modes of control of the ␣-glucan phosphorylase MalP of the Gram-positive Corynebacterium glutamicum. In accordance to the proposed function of the malP gene product as MalP, we found transcription of malP to be regulated in response to the carbon source. Moreover, malP transcription is shown to depend on the growth phase and to occur independently of the cell glycogen content. Surprisingly, we also found MalP activity to be tightly regulated competitively by the presence of ADP-glucose, an intermediate of glycogen synthesis. Since the latter is considered a typical feature of GlgPs, we propose that C. glutamicum MalP acts as both maltodextrin and glycogen phosphorylase and, based on these findings, we question the current system for classification of bacterial ␣-glucan phosphorylases. IMPORTANCEBacterial ␣-glucan phosphorylases have been classified conferring to their purpose as either glycogen or maltodextrin phosphorylases. We found transcription of malP in C. glutamicum to be regulated in response to the carbon source, which is recognized as typical for maltodextrin phosphorylases. Surprisingly, we also found MalP activity to be tightly regulated competitively by the presence of ADP-glucose, an intermediate of glycogen synthesis. The latter is considered a typical feature of GlgPs. These findings, taken together, suggest that C. glutamicum MalP is the first ␣-glucan phosphorylase that does not fit into the current system for classification of bacterial ␣-glucan phosphorylases and exemplifies the complex mechanisms underlying the control of glycogen content and maltose metabolism in this model organism.T he ␣-glucan phosphorylases (EC 2.4.1.1) catalyze the reversible cleavage of ␣-1,4-glycosidic linkages in polysaccharides, thereby liberating ␣-glucose-1-phosphate. By this means, ␣-glucan phosphorylases participate in metabolic processes such as degradation of the intracellular storage polysaccharides glycogen and starch (1, 2), as well as the degradation of maltodextrins formed both in the course of the maltose metabolism of various bacteria (3, 4) and in the cytosol of plant leaves (5-7). Several ␣-glucan phosphorylases have been extensively studied, their crystal structures have been solved, and the catalytic mechanisms have been described (8-11). Although the catalytic mechanisms appear to be similar in all hitherto characterized phosphorylases (12-14)...

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Section: Resultssupporting

confidence: 62%

The α-Glucan Phosphorylase MalP of Corynebacterium glutamicum Is Subject to Transcriptional Regulation and Competitive Inhibition by ADP-Glucose

et al. 2015

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“…S2 in the supplemental material). The identified TSS and promoter regions were manually checked and were adjusted according to the nucleotide distribution within the C. glutamicum promoter sequences (34). These results suggest that the paa gene cluster of strain AS 1.542 is organized into six transcription units: paaTK, paaABCDEGJFH, paaR, paaI, paaY, and paaZ.…”

Section: Resultsmentioning

confidence: 99%

Phenylacetic Acid Catabolism and Its Transcriptional Regulation in Corynebacterium glutamicum

Chen

Kohl

Rückert

et al. 2012

Appl Environ Microbiol

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fThe industrially important organism Corynebacterium glutamicum has been characterized in recent years for its robust ability to assimilate aromatic compounds. In this study, C. glutamicum strain AS 1.542 was investigated for its ability to catabolize phenylacetic acid (PAA). The paa genes were identified; they are organized as a continuous paa gene cluster. The type strain of C. glutamicum, ATCC 13032, is not able to catabolize PAA, but the recombinant strain ATCC 13032/ pEC-K18mob2::paa gained the ability to grow on PAA. The paaR gene, encoding a TetR family transcription regulator, was studied in detail. Disruption of paaR in strain AS 1.542 resulted in transcriptional increases of all paa genes. Transcription start sites and putative promoter regions were determined. An imperfect palindromic motif (5=-ACTNACCGNNCGNNCGG TNAGT-3=; 22 bp) was identified in the upstream regions of paa genes. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of PaaR to this motif, and phenylacetyl coenzyme A (PA-CoA) blocked binding. It was concluded that PaaR is the negative regulator of PAA degradation and that PA-CoA is the PaaR effector. In addition, GlxR binding sites were found, and binding to GlxR was confirmed. Therefore, PAA catabolism in C. glutamicum is regulated by the pathway-specific repressor PaaR, and also likely by the global transcription regulator GlxR. By comparative genomic analysis, we reconstructed orthologous PaaR regulons in 57 species, including species of Actinobacteria, Proteobacteria, and Flavobacteria, that carry PAA utilization genes and operate by conserved binding motifs, suggesting that PaaR-like regulation might commonly exist in these bacteria.

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“…Leaderless transcripts have been found frequently in C. glutamicum (24). The potential Ϫ10 (TACGAT) region and Ϫ35 (CTGACA) region that are similar to the respective consensus sequences (TANANT and TTGNCA) of the C. glutamicum SigA-dependent promoter (23) are found in the upstream region of the gnd gene.…”

Section: Resultsmentioning

confidence: 99%

Coordinated Regulation of gnd , Which Encodes 6-Phosphogluconate Dehydrogenase, by the Two Transcriptional Regulators GntR1 and RamA in Corynebacterium glutamicum

et al. 2012

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The transcriptional regulation of Corynebacterium glutamicum gnd, encoding 6-phosphogluconate dehydrogenase, was investigated. Two transcriptional regulators, GntR1 and RamA, were isolated by affinity purification using gnd promoter DNA. GntR1 was previously identified as a repressor of gluconate utilization genes, including gnd. Involvement of RamA in gnd expression had not been investigated to date. The level of gnd mRNA was barely affected by the single deletion of ramA. However, gnd expression was downregulated in the ramA gntR1 double mutant compared to that of the gntR1 single mutant, suggesting that RamA activates gnd expression. Two RamA binding sites are found in the 5= upstream region of gnd. Mutation proximal to the transcriptional start site diminished the gluconate-dependent induction of gnd-lacZ. DNase I footprinting assay revealed two GntR1 binding sites, with one corresponding to a previously proposed site that overlaps with the ؊10 region. The other site overlaps the RamA binding site. GntR1 binding to this newly identified site inhibits DNA binding of RamA. Therefore, it is likely that GntR1 represses gnd expression by preventing both RNA polymerase and RamA binding to the promoter. In addition, DNA binding activity of RamA was reduced by high concentrations of NAD(P)H but not by NAD(P), implying that RamA senses the redox perturbation of the cell.

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Sigma factors and promoters in Corynebacterium glutamicum

Cited by 111 publications

References 108 publications

The α-Glucan Phosphorylase MalP of Corynebacterium glutamicum Is Subject to Transcriptional Regulation and Competitive Inhibition by ADP-Glucose

The α-Glucan Phosphorylase MalP of Corynebacterium glutamicum Is Subject to Transcriptional Regulation and Competitive Inhibition by ADP-Glucose

Phenylacetic Acid Catabolism and Its Transcriptional Regulation in Corynebacterium glutamicum

Coordinated Regulation of gnd , Which Encodes 6-Phosphogluconate Dehydrogenase, by the Two Transcriptional Regulators GntR1 and RamA in Corynebacterium glutamicum

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