Two functionally different glucose phosphotransferase transport systems in <i>Streptococcus mutans</i> and <i>Streptococcus sobrinus</i>

Néron, Sonia; Vadeboncoeur, Christian

doi:10.1111/j.1399-302x.1987.tb00302.x

Cited by 17 publications

(18 citation statements)

References 45 publications

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“…Glucose PTS activity reached higher levels when cells were grown in glucose (Fig. 3A), confirming earlier observations that S. mutans possesses a constitutive and an inducible glucose PTS (1,19). Growth in galactose did not dramatically enhance galactose-specific PTS activity in the wild-type strain, in contrast to what was observed for cells grown in lactose (Fig.…”

Section: Resultssupporting

confidence: 90%

Galactose Metabolism by Streptococcus mutans

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Chen

Burne

2004

Appl Environ Microbiol

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The galK gene, encoding galactokinase of the Leloir pathway, was insertionally inactivated in Streptococcus mutans UA159. The galK knockout strain displayed only marginal growth on galactose, but growth on glucose or lactose was not affected. In strain UA159, the sugar phosphotransferase system (PTS) for lactose and the PTS for galactose were induced by growth in lactose and galactose, although galactose PTS activity was very low, suggesting that S. mutans does not have a galactose-specific PTS and that the lactose PTS may transport galactose, albeit poorly. To determine if the galactose growth defect of the galK mutant could be overcome by enhancing lactose PTS activity, the gene encoding a putative repressor of the operon for lactose PTS and phospho-␤-galactosidase, lacR, was insertionally inactivated. A galK and lacR mutant still could not grow on galactose, although the strain had constitutively elevated lactose PTS activity. The glucose PTS activity of lacR mutants grown in glucose was lower than in the wild-type strain, revealing an influence of LacR or the lactose PTS on the regulation of the glucose PTS. Mutation of the lacA gene of the tagatose pathway caused impaired growth in lactose and galactose, suggesting that galactose can only be efficiently utilized when both the Leloir and tagatose pathways are functional. A mutation of the permease in the multiple sugar metabolism operon did not affect growth on galactose. Thus, the galactose permease of S. mutans is not present in the gal, lac, or msm operons.Streptococcus mutans is considered the primary etiological agent of dental caries. Its ability to metabolize a variety of sugars to generate acids is directly related to its cariogenicity. S. mutans can metabolize galactose by two distinct pathways: tagatose 6-phosphate and Leloir. In the tagatose pathway, the galactose moiety of lactose, and possibly galactose alone, can be transported and phosphorylated by a lactose-specific (lacEF) phosphoenolpyruvate:phosphotransferase system (PTS). The resultant galactose 6-phosphate generated by an intracellular 6-phospho-␤-galactosidase (lacG) is converted into tagatose 6-phosphate, to tagatose 1,6-bisphosphate, and then to glyceraldehyde 3-phosphate and dihydroxyacetone by the enzymes galactose 6-phosphate isomerase (lacAB), tagatose 6-phosphate kinase (lacC), and tagatose 1,6-bisphospahte aldolase (lacD), respectively. In S. mutans, the genes encoding the tagatose 6-phosphate pathway are arranged as part of the lac operon (15). In the Leloir pathway, galactose enters the cell via an as-yet-unidentified permease, where it is phosphorylated by galactokinase (galK) to yield galactose 1-phosphate, which is then converted into glucose 1-phosphate by hexose1-phosphate uridyltransferase (galT) and UDP-glucose epimerase (galE). The resulting glucose 1-phosphate can enter the glycolytic pathway.The genes encoding the Leloir pathway are arranged as an operon (galKTE) (4) located downstream of the multiple sugar metabolism (msm) operon (Fig. 1). The msm operon is responsi...

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Section: Resultssupporting

confidence: 90%

Galactose Metabolism by Streptococcus mutans

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Chen

Burne

2004

Appl Environ Microbiol

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“…Growth in 0.2% mannose was faster for JAM1 (doubling time Х180 min) than for the wild-type strain (doubling time Х255 min). This finding is in contrast with that reported for S. mutans GS-5, in which a spontaneously arising EII Man -deficient strain grew more slowly than the parent in glucose but growth in mannose was unaffected (23,24). Of note, no significant differences in growth rates were observed between the wild-type strain and JAM1 when 0.2% fructose was used as the sole carbohydrate source (Table 2).…”

Section: Characteristics Of Eiiabcontrasting

confidence: 88%

“…Lower levels of glucose-specific PTS activity were observed in the wild-type strain grown in mannose than were seen for (23). When JAM1 was grown in mannose, the mannose PTS activity was restored to the levels seen in the wild-type strain grown under the same conditions (Fig.…”

Section: Characteristics Of Eiiabmentioning

confidence: 77%

“…In addition to transporting glucose, fructose, and mannose, the EII Man of Lactobacillus pentosus has been shown to be involved in the transport of xylose (9). Finally, the involvement of EII Man in carbon catabolite repression (CCR) was previously suggested for S. salivarius, Streptococcus bovis, and L. pentosus (8,12,17 Man grew as well as the parent strain on mannose, so the presence of an inducible mannose PTS was therefore suggested for this organism (23). A variety of studies have highlighted the importance of carbohydrate source and availability in the regulation of expression of critical virulence attributes of S. mutans.…”

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confidence: 92%

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Characterization of Streptococcus mutans Strains Deficient in EIIAB ^Man of the Sugar Phosphotransferase System

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Chen

Burne

2003

Appl Environ Microbiol

113

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The phosphoenolpyruvate:sugar phosphotransferase system (PTS) is the major sugar uptake system in oral streptococci. The role of EIIAB Man (encoded by manL) in gene regulation and sugar transport was investigated in Streptococcus mutans UA159. The manL knockout strain, JAM1, grew more slowly than the wild-type strain in glucose but grew faster in mannose and did not display diauxic growth, indicating that EIIAB Man is involved in sugar uptake and in carbohydrate catabolite repression. PTS assays of JAM1, and of strains lacking the inducible (fruI) and constitutive (fruCD) EII fructose, revealed that S. mutans EIIAB Man transported mannose and glucose and provided evidence that there was also a mannose-inducible or glucose-repressible mannose PTS. Additionally, there appears to be a fructose PTS that is different than FruI and FruCD. To determine whether EIIAB Man controlled expression of the known virulence genes, glucosyltransferases (gtfBC) and fructosyltransferase (ftf) promoter fusions of these genes were established in the wild-type and EIIAB Man -deficient strains. In the manL mutant, the level of chloramphenicol acetyltransferase activity expressed from the gtfBC promoter was up to threefold lower than that seen with the wild-type strain at pH 6 and 7, indicating that EIIAB Man is required for optimal expression of gtfBC. No significant differences were observed between the mutant and the wild-type background in ftf regulation, with the exception that under glucose-limiting conditions at pH 7, the mutant exhibited a 2.1-fold increase in ftf expression. Two-dimensional gel analysis of batch-grown cells of the EIIAB Man -deficient strain indicated that the expression of at least 38 proteins was altered compared to that seen with the wild-type strain, revealing that EIIAB Man has a pleiotropic effect on gene expression.Oral streptococci depend on dietary carbohydrates and carbohydrates presented in oral secretions for growth and persistence in the mouth. The ability of oral streptococci to metabolize a wide variety of carbohydrates to produce organic acids is directly related to their ability to elicit dental caries. The phosphoenolpyruvate (PEP):sugar phosphotransferase system (PTS) is the primary sugar transport system in oral streptococci, especially under carbohydrate-limiting conditions, and plays important roles in global control of gene expression (20,29,30,37,38). The PTS consists of two proteins that are common to all PTS substrates, enzyme I (EI) and the heatstable phosphocarrier protein HPr, as well as a variety of sugar-specific permeases, known as EII complexes, which catalyze the transport and concomitant phosphorylation of the substrate. The EII complexes usually consist of three domains, A, B, and C, but sometimes a fourth domain, D, is required (20, 29). The A and B domains participate in phosphorylation of the cognate substrates, whereas the C and D domains comprise the membrane permeases. The EII domains can either be covalently linked as a single protein or can be present in various combi...

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“…The presence of a glucose PTS in S. mutans was reported decades ago (9,18,31). In fact, S. mutans harbors at least two glucose PTS transporters (21,36). One of them has been characterized and demonstrated to take up mannose, glucose, and 2-deoxyglucose (2,36).…”

Section: Fig 3 Differential Transcription Of Genes For Pts Eii and mentioning

confidence: 99%

Global Transcriptional Analysis of Streptococcus mutans Sugar Transporters Using Microarrays

2007

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The transport of carbohydrates by Streptococcus mutans is accomplished by the phosphoenolpyruvatephosphotransferase system (PTS) and ATP-binding cassette (ABC) transporters. To undertake a global transcriptional analysis of all S. mutans sugar transporters simultaneously, we used a whole-genome expression microarray. Global transcription profiles of S. mutans UA159 were determined for several monosaccharides (glucose, fructose, galactose, and mannose), disaccharides (sucrose, lactose, maltose, and trehalose), a ␤-glucoside (cellobiose), oligosaccharides (raffinose, stachyose, and maltotriose), and a sugar alcohol (mannitol). The results revealed that PTSs were responsible for transport of monosaccharides, disaccharides, ␤-glucosides, and sugar alcohol. Six PTSs were transcribed only if a specific sugar was present in the growth medium; thus, they were regulated at the transcriptional level. These included transporters for fructose, lactose, cellobiose, and trehalose and two transporters for mannitol. Three PTSs were repressed under all conditions tested. Interestingly, five PTSs were always highly expressed regardless of the sugar source used, presumably suggesting their availability for immediate uptake of most common dietary sugars (glucose, fructose, maltose, and sucrose). The ABC transporters were found to be specific for oligosaccharides, raffinose, stachyose, and isomaltosaccharides. Compared to the PTSs, the ABC transporters showed higher transcription under several tested conditions, suggesting that they might be transporting multiple substrates.Numerous studies have implicated Streptococcus mutans as the principal causative agent of human dental caries. It is well known that host diet is important for S. mutans cariogenicity, and sugar metabolism of this bacterium plays a key role in the formation of caries. S. mutans is able to metabolize a wide range of carbohydrates that may originate from dietary sources or from host macromolecules. If the diet is rich in sugars, especially sucrose, the end product of sugar metabolism is mostly lactic acid that can lead to demineralization of tooth enamel. Therefore, sugar transport and metabolism by this bacterium are directly related to the onset and development of dental caries.In bacteria, sugar substrates are taken up by ATP-binding cassette (ABC) transporters, galactoside-pentose hexuronide (GPH) translocators, and, most commonly, phosphoenolpyruvate-sugar phosphotransferase systems (PTSs). The bacterial PTSs are responsible for the binding, transmembrane transport, and phosphorylation of numerous sugar substrates. These systems are also involved in the regulation of a variety of metabolic and transcriptional processes (29, 37). The PTS consists of two nonspecific energy-coupling components, enzyme I (EI) and a heat-stable protein (HPr), as well as several sugarspecific multiprotein permeases known as EII. In most cases, EIIA and EIIB are located in the cytoplasm, while EIIC acts as a membrane channel (37). Fourteen PTS systems have been found in S. mutans UA1...

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Two functionally different glucose phosphotransferase transport systems in Streptococcus mutans and Streptococcus sobrinus

Cited by 17 publications

References 45 publications

Galactose Metabolism by Streptococcus mutans

Galactose Metabolism by Streptococcus mutans

Characterization of Streptococcus mutans Strains Deficient in EIIAB ^Man of the Sugar Phosphotransferase System

Global Transcriptional Analysis of Streptococcus mutans Sugar Transporters Using Microarrays

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Two functionally different glucose phosphotransferase transport systems in Streptococcus mutans and Streptococcus sobrinus

Cited by 17 publications

References 45 publications

Galactose Metabolism by Streptococcus mutans

Galactose Metabolism by Streptococcus mutans

Characterization of Streptococcus mutans Strains Deficient in EIIAB Man of the Sugar Phosphotransferase System

Global Transcriptional Analysis of Streptococcus mutans Sugar Transporters Using Microarrays

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Product

Resources

About

Characterization of Streptococcus mutans Strains Deficient in EIIAB ^Man of the Sugar Phosphotransferase System