The Phosphotransferase System of &lt;i&gt;Corynebacterium glutamicum&lt;/i&gt;: Features of Sugar Transport and Carbon Regulation

Moon, Min-Woo; Park, Sun-Yang; Choi, Soo Keun; Lee, Jung-Kee

doi:10.1159/000096458

Cited by 61 publications

(36 citation statements)

References 58 publications

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“…This is in strong contrast to E. coli and other gram-negative bacteria, which have only one CRP and one adenylate cyclase. CRP homologs have been identified in streptomycetes (18), where the regulator plays a role in germination, and in corynebacteria, where CRPs have been associated with global carbon regulation (39). Although the potential mechanisms of global control of carbon metabolism in both M. smegmatis and M. tuberculosis are not evident from the bioinformatic analysis of their genomes, these findings provide hypotheses for further experiments.…”

Section: Discussionmentioning

confidence: 96%

A Genomic View of Sugar Transport inMycobacterium smegmatisandMycobacterium tuberculosis

et al. 2007

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We present a comprehensive analysis of carbohydrate uptake systems of the soil bacterium Mycobacterium smegmatis and the human pathogen Mycobacterium tuberculosis. Our results show that M. smegmatis has 28 putative carbohydrate transporters. The majority of sugar transport systems (19/28) in M. smegmatis belong to the ATP-binding cassette (ABC) transporter family. In contrast to previous reports, we identified genes encoding all components of the phosphotransferase system (PTS), including permeases for fructose, glucose, and dihydroxyacetone, in M. smegmatis. It is anticipated that the PTS of M. smegmatis plays an important role in the global control of carbon metabolism similar to those of other bacteria. M. smegmatis further possesses one putative glycerol facilitator of the major intrinsic protein family, four sugar permeases of the major facilitator superfamily, one of which was assigned as a glucose transporter, and one galactose permease of the sodium solute superfamily. Our predictions were validated by gene expression, growth, and sugar transport analyses. Strikingly, we detected only five sugar permeases in the slow-growing species M. tuberculosis, two of which occur in M. smegmatis. Genes for a PTS are missing in M. tuberculosis. Our analysis thus brings the diversity of carbohydrate uptake systems of fast-and a slow-growing mycobacteria to light, which reflects the lifestyles of M. smegmatis and M. tuberculosis in their natural habitats, the soil and the human body, respectively.The growth and nutritional requirements of mycobacteria have been intensely studied since the discovery of Mycobacterium tuberculosis (32). This resulted in an overwhelming body of literature on the physiology of mycobacterial metabolism in the years before the dawn of molecular biology (20,53,54). Carbon metabolism of mycobacteria has attracted renewed interest since the discovery that M. tuberculosis relies on the glyoxylate cycle for survival in mice (36,41). This observation indicates that M. tuberculosis uses lipids as the main carbon source during infection. On the other side, genes that encode a putative disaccharide transporter were essential for M. tuberculosis during the first week of infection, indicating that M. tuberculosis may switch its main carbon source from carbohydrates to lipids with the onset of the adaptive immune response (61). However, the nutrients and the corresponding uptake proteins are unknown for M. tuberculosis inside the human host. Surprisingly, this is also true for M. tuberculosis growing in vitro and for Mycobacterium smegmatis, which is often used as a fast-growing, nonpathogenic model organism to learn more about basic mycobacterial physiology. There is no doubt that the uptake pathways have been adapted to the habitats of M. tuberculosis and M. smegmatis, the human body and soil, respectively. Thus, much can be learned about the lifestyles of both organisms by a comparison of the complements of specific nutrient uptake proteins. Previously, 38 ATP-binding cassette (ABC) transport proteins...

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Section: Discussionmentioning

confidence: 96%

A Genomic View of Sugar Transport inMycobacterium smegmatisandMycobacterium tuberculosis

et al. 2007

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“…The components of PTS consist of two common cytoplasmic proteins, enzyme I (EI) and HPr, and sugar-specific membranebound proteins, enzyme IIs (EIIs). There are three EIIs, encoded by ptsG, ptsF, and ptsS, which are specific to glucose, fructose, and sucrose, respectively, that have been identified in C. glutamicum, (33,34). In addition, unlike ATCC 13032, one of the most representative strains of C. glutamicum, C. glutamicum R has two other EIIs encoded by bglF and bglF2, which are specific to ␤-glucoside (35,36).…”

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confidence: 99%

Enhanced Glucose Consumption and Organic Acid Production by Engineered Corynebacterium glutamicum Based on Analysis of a pfkB1 Deletion Mutant

Hasegawa

Tanaka

Suda

et al. 2017

Appl Environ Microbiol

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In the analysis of a carbohydrate metabolite pathway, we found interesting phenotypes in a mutant strain of Corynebacterium glutamicum deficient in pfkB1, which encodes fructose-1-phosphate kinase. After being aerobically cultivated with fructose as a carbon source, this mutant consumed glucose and produced organic acid, predominantly L-lactate, at a level more than 2-fold higher than that of the wild-type grown with glucose under conditions of oxygen deprivation. This considerably higher fermentation capacity was unique for the combination of pfkB1 deletion and cultivation with fructose. In the metabolome and transcriptome analyses of this strain, marked intracellular accumulation of fructose-1-phosphate and significant upregulation of several genes related to the phosphoenolpyruvate:carbohydrate phosphotransferase system, glycolysis, and organic acid synthesis were identified. We then examined strains overexpressing several of the identified genes and demonstrated enhanced glucose consumption and organic acid production by these engineered strains, whose values were found to be comparable to those of the model pfkB1 deletion mutant grown with fructose. L-Lactate production by the ppc deletion mutant of the engineered strain was 2,390 mM (i.e., 215 g/liter) after 48 h under oxygen deprivation, which was a 2.7-fold increase over that of the wild-type strain with a deletion of ppc.IMPORTANCE Enhancement of glycolytic flux is important for improving microbiological production of chemicals, but overexpression of glycolytic enzymes has often resulted in little positive effect. That is presumably because the central carbon metabolism is under the complex and strict regulation not only transcriptionally but also posttranscriptionally, for example, by the ATP/ADP ratio. In contrast, we studied a mutant strain of Corynebacterium glutamicum that showed markedly enhanced glucose consumption and organic acid production and, based on the findings, identified several genes whose overexpression was effective in enhancing glycolytic flux under conditions of oxygen deprivation. These results will further understanding of the regulatory mechanisms of glycolytic flux and can be widely applied to the improvement of the microbial production of useful chemicals.KEYWORDS Corynebacterium glutamicum, fructose metabolism, fructose-1-phosphate kinase, organic acid production, overexpression of glycolytic genes, regulation of glycolytic flux C orynebacterium glutamicum has been used as a powerful workhorse in the industrial production of amino acids, such as L-glutamate and L-lysine (1, 2). This organism behaves rather similarly to an aerobe because little growth is identified anaerobically without an alternative electron acceptor, nitrate (3, 4). In contrast, under oxygen-deprived conditions, C. glutamicum metabolizes glucose to L-lactate, succinate,

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“…BglF is a member of the PtsG family of enzyme II proteins, and it is known that the bgl PTS EII of E. coli has the ability to transport glucose (36). In the C. glutamicum ATCC 13032 strain, disruption of ptsG alone resulted in the marked decrease of glucose consumption (28,29), in contrast to the high glucose utilization ability remaining in the C. glutamicum R ptsG-deficient strain. This is explained by the presence of disrupted bgl PTS genes found in the C. glu- tamicum ATCC 13032 genome (41).…”

Section: Discussionmentioning

confidence: 98%

Translation Efficiency of Antiterminator Proteins Is a Determinant for the Difference in Glucose Repression of Two β-Glucoside Phosphotransferase System Gene Clusters inCorynebacterium glutamicumR

et al. 2011

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Corynebacterium glutamicum R has two ␤-glucoside phosphoenolpyruvate, carbohydrate phosphotransferase systems (PTS) encoded by bglF and bglF2 located in the respective clusters, bglF-bglA-bglG and bglF2-bglA2-bglG2. Previously, we reported that whereas ␤-glucoside-dependent induction of bglF is strongly repressed by glucose, glucose repression of bglF2 is very weak. Here, we reveal the mechanism behind the different effects of glucose on the two bgl genes. Deletion of the ribonucleic antiterminator sequence and transcriptional terminator located upstream of the translation initiation codon of bglF markedly relieved the glucose repression of a bglF-lacZ fusion, indicating that glucose affects the antitermination mechanism that is responsible for the ␤-glucoside-dependent induction of the bglF cluster. The glucose repression of bglF mRNA was also relieved by introducing a multicopy plasmid carrying the bglG gene encoding an antiterminator of the bglF cluster. Moreover, replacement of the GUG translation initiation codon of bglG with AUG was effective in relieving the glucose repression of bglF and bglG. Inversely, expression of bglF2 and bglG2 was subject to strict glucose repression in a mutant strain in which the AUG translation initiation codon of bglG2 encoding antiterminator of the bglF2 cluster was replaced with GUG. These results suggest that the translation initiation efficiency of the antiterminator proteins, at least in part, determines whether the target genes are subject to glucose repression. We also found that bglF expression was induced by glucose in the BglG-overexpressing strains, which may be explained by the ability of BglF to transport glucose.In many bacterial cells, ␤-glucosides are taken up via the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS), which is consequently important for the acquisition of various carbohydrates (22, 34). The PTS consists of two common cytoplasmic proteins, enzyme I (EI) and HPr, and an array of carbohydrate-specific enzyme II (EII) permeases. The phosphoryl group from phosphoenolpyruvate is sequentially transferred to EI, HPr, EII, and finally to the carbohydrate as it is translocated across the membrane.An antitermination mechanism has a pivotal role in regulation of ␤-glucoside PTS genes in many bacteria. The regulation has been well studied in Escherichia coli and Bacillus subtilis. In the antitermination regulatory mechanism, transcription stops at a terminator sequence present in the 5Ј untranslated region (UTR) of the target mRNA. In the presence of substrate sugar, a transcriptional antiterminator protein of the BglG/ SacY family binds to the ribonucleic antiterminator (RAT) sequence partially overlapping the transcriptional terminator and thereby results in transcription elongation to the end of the target gene (1,5,38).An antiterminator such as E. coli BglG or B. subtilis LicT is inactivated by phosphorylation at the PTS regulation domain 1 (PRD-1) by a ␤-glucoside EII. Concomitant with PTS-dependent uptake and phosphorylation of the subs...

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The Phosphotransferase System of <i>Corynebacterium glutamicum</i>: Features of Sugar Transport and Carbon Regulation

Cited by 61 publications

References 58 publications

A Genomic View of Sugar Transport inMycobacterium smegmatisandMycobacterium tuberculosis

A Genomic View of Sugar Transport inMycobacterium smegmatisandMycobacterium tuberculosis

Enhanced Glucose Consumption and Organic Acid Production by Engineered Corynebacterium glutamicum Based on Analysis of a pfkB1 Deletion Mutant

Translation Efficiency of Antiterminator Proteins Is a Determinant for the Difference in Glucose Repression of Two β-Glucoside Phosphotransferase System Gene Clusters inCorynebacterium glutamicumR

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