The molecular mechanism of dicarboxylic acid transport in escherichia coli K 12

Lo, Theodore C. Y.

doi:10.1002/jss.400070316

Cited by 42 publications

(27 citation statements)

References 19 publications

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“…DISCUSSION An anaerobic dicarboxylate transport system different from the aerobic dicarboxylate transport (det) system. The anaerobic fumarate transport system differs in all tested parameters from the aerobic dicarboxylate transport system (9,14). The aerobic system shows a rather high affinity for the substrates combined with relatively low activities, which is characteristic of binding-protein-dependent transport systems.…”

Section: Resultsmentioning

confidence: 90%

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Anaerobic fumarate transport in Escherichia coli by an fnr-dependent dicarboxylate uptake system which is different from the aerobic dicarboxylate uptake system

1992

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Escherichia coli grown anaerobically with fumarate as electron acceptor is able to take up C4-dicarboxylates by a specific transport system. The system differs in all tested parameters from the known aerobic C4-dicarboxylate transporter. The anaerobic transport system shows higher transport rates (95 ,umol/g [dry weight] per min versus 30 ,umol/g/min) and higher Kms (400 versus 30 ,uM) for fumarate than for the aerobic system. Mutants lacking the aerobic dicarboxylate uptake system are able to grow anaerobically at the expense of fumarate respiration and transport dicarboxylates with wild-type rates after anaerobic but not after aerobic growth. Transport by the anaerobic system is stimulated by preloading the bacteria with dicarboxylates. The anaerobic transport system catalyzes homologous and heterologous antiport of dicarboxylates, whereas the aerobic system operates only in the unidirectional mode. The anaerobic antiport is measurable only in anaerobically grown bacteria withfinr' backgrounds. Additionally, the system is inhibited by incubation of resting bacteria with physiological electron acceptors such as 02, nitrate, dimethyl sulfoxide, and fumarate. The inhibition is reversed by the presence of reducing agents. It is suggested that the physiological role of the system is a fumarate/succinate antiport under conditions of fumarate respiration.

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Section: Resultsmentioning

confidence: 90%

“…In aerobic bacteria, the uptake of dicarboxylic acids appears to be catalyzed by a binding-protein-dependent transport system (14). The periplasmic binding protein, which is probably encoded by the cbt gene, was isolated (15).…”

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confidence: 99%

Anaerobic fumarate transport in Escherichia coli by an fnr-dependent dicarboxylate uptake system which is different from the aerobic dicarboxylate uptake system

1992

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“…Under aerobic growth conditions, unidirectional uptake of C 4 dicarboxylates (fumarate, succinate, and malate) and aspartate, but no export, is catalyzed (5,12). This transport is effected by a binding protein-dependent carrier or by a secondary carrier which is driven by the electrochemical H ϩ gradient over the membrane (10,17). The dctA and dctB genes have been shown to be related to the aerobic carriers (3,17,23).…”

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confidence: 99%

“…This transport is effected by a binding protein-dependent carrier or by a secondary carrier which is driven by the electrochemical H ϩ gradient over the membrane (10,17). The dctA and dctB genes have been shown to be related to the aerobic carriers (3,17,23). The dctA gene has been sequenced (23), but none of the carriers has been clearly defined so far by genetic or biochemical means.…”

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Identification of a third secondary carrier (DcuC) for anaerobic C4-dicarboxylate transport in Escherichia coli: roles of the three Dcu carriers in uptake and exchange

1996

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In Escherichia coli, two carriers (DcuA and DcuB) for the transport of C 4 dicarboxylates in anaerobic growth were known. Here a novel gene dcuC was identified encoding a secondary carrier (DcuC) for C 4 dicarboxylates which is functional in anaerobic growth. The dcuC gene is located at min 14.1 of the E. coli map in the counterclockwise orientation. The dcuC gene combines two open reading frames found in other strains of E. coli K-12. The gene product (DcuC) is responsible for the transport of C 4 dicarboxylates in DcuA-DcuB-deficient cells. The triple mutant (dcuA dcuB dcuC) is completely devoid of C 4 -dicarboxylate transport (exchange and uptake) during anaerobic growth, and the bacteria are no longer capable of growth by fumarate respiration. DcuC, however, is not required for C 4 -dicarboxylate uptake in aerobic growth. The dcuC gene encodes a putative protein of 461 amino acid residues with properties typical for secondary procaryotic carriers. DcuC shows sequence similarity to the two major anaerobic C 4 -dicarboxylate carriers DcuA and DcuB. Mutants producing only DcuA, DcuB, or DcuC were prepared. In the mutants, DcuA, DcuB, and DcuC were each able to operate in the exchange and uptake mode.In Escherichia coli, various transport activities for C 4 dicarboxylates are known. Under aerobic growth conditions, unidirectional uptake of C 4 dicarboxylates (fumarate, succinate, and malate) and aspartate, but no export, is catalyzed (5, 12). This transport is effected by a binding protein-dependent carrier or by a secondary carrier which is driven by the electrochemical H ϩ gradient over the membrane (10, 17). The dctA and dctB genes have been shown to be related to the aerobic carriers (3, 17, 23). The dctA gene has been sequenced (23), but none of the carriers has been clearly defined so far by genetic or biochemical means. Bacteria grown under anaerobic conditions, on the other hand, catalyze exchange, uptake, and efflux of C 4 dicarboxylates (5, 6). Fumarate/succinate exchange is required during fumarate respiration where the acceptor fumarate has to be taken up and the product succinate has to be excreted. Net C 4 -dicarboxylate uptake is required for anaerobic growth with C 4 dicarboxylates as the C source. Citrate fermentation, on the other hand, which produces 1 succinate per citrate, depends on a C 4 -dicarboxylate efflux system. The exchange reaction of the C 4 dicarboxylates is an electroneutral process, whereas uptake and efflux are electrogenic symport reactions, presumably of the dicarboxylate 2Ϫ with 3 H ϩ (6). The anaerobic transport activities were found only in bacteria grown under anaerobic conditions, and the synthesis requires intact FNR (named FNR for fumarate nitrate reductase regulator), the transcriptional regulator of anaerobic metabolism (5, 6, 25).Recently two homologous genes (dcuA and dcuB) were identified in E. coli which encode two C 4 -dicarboxylate carriers, DcuA and DcuB (22). The carriers (DcuA and DcuB) were complementary to each other, and each was sufficient for fumarate/s...

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“…In addition, S. Typhimurium possesses the genes for two other C 4 -dicarboxylate-transport systems: (1) the anaerobic Dcu dicarboxylate-transporter system, which appears to be involved in fumarate respiration rather than C 4 -dicarboxylate utilization and as part of this function actually results in succinate efflux from the cytoplasm (Janausch et al, 2002), and (2) a homologue of the DctA H + /Na + : C 4 -dicarboxylate/dicarboxylic amino acid symporter, which was found to be a major C 4 -dicarboxylate transporter during aerobic growth in E. coli. (Lo, 1977;Lo & Bewick, 1981). Whether this complex is expressed under the conditions tested in this study has not been demonstrated, but recent evidence suggests that cbt may be an allele of the ferric-enterobactintransport component gene fepA, which is iron regulated (Braun & Braun, 2002) in both E. coli and Salmonella.…”

Section: Results and Disccusionmentioning

confidence: 99%

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

et al. 2005

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Salmonella enterica serovar Typhimurium (S. Typhimurium) elicits the starvation-stress response (SSR) due to starvation for an essential nutrient, e.g. a carbon/energy source (C-source). As part of the SSR, the alternative sigma factor s E is activated and induced. The authors suspect that this activation is, in part, triggered by changes in the S. Typhimurium cell envelope occurring during the adaptation from growth to carbon/energy starvation (C-starvation), and resulting in an increased need for s E -regulated factors involved in the proper folding and assembly of newly synthesized proteins destined for this extracytoplasmic compartment. This led to the hypothesis that a s E activation signal might arise during C-source shifts that cause the induction of proteins localized to the extracytoplasmic compartment, i.e. the outer membrane or periplasm, of the cell. To test this hypothesis, cultures were grown in minimal medium containing enough glucose to reach mid-exponential-phase, plus a non-limiting amount of a secondary 'less-preferred' but utilizable carbon/energy source. The s E activity was then monitored using plasmids carrying rpoEP1-and rpoEP2-lacZ transcriptional fusions, which exhibit s E -independent and -dependent lacZ expression, respectively. The secondary C-sources maltose, succinate and citrate, which have extracytoplasmic components involved in their utilization (e.g. LamB), resulted in a discernible diauxic lag period and a sustained increase in s E activity. Growth transition from glucose to other utilizable phosphotransferase (PTS) and non-PTS C-sources, such as trehalose, mannose, mannitol, fructose, glycerol, D-galactose or L-arabinose, did not cause a discernible diauxic lag period or a sustained increase in s E activity. Interestingly, a shift from glucose to melibiose, which does not use an extracytoplasmic-localized protein for uptake, did cause an observable diauxic lag period but did not result in a sustained increase in s E activity. In addition, overexpression of LamB from an arabinose-inducible promoter leads to a significant increase in s E activity in the absence of a glucose to maltose shift or C-starvation. Furthermore, a DlamB : : V-Km r mutant, lacking the LamB maltoporin, exhibited an approximately twofold reduction in the sustained s E activity observed during a glucose to maltose shift, again supporting the hypothesis. Interestingly, the LamB protein lacks the typical Y-X-F terminal tripeptide of the OmpC-like peptides that activate DegS protease activity leading to s E activation. It does, however, possess a terminal pentapeptide (Q-M-E-I-W-W) that may function as a ligand for a putative class II PDZ-binding site. The authors therefore propose that the s E regulon of S. Typhimurium not only is induced in response to deleterious environmental conditions, but also plays a role in the adaptation of cells to new growth conditions that necessitate changes in the extracytoplasmic compartment of the cell, which may involve alternative signal recognition and activation pathways t...

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The molecular mechanism of dicarboxylic acid transport in escherichia coli K 12

Cited by 42 publications

References 19 publications

Anaerobic fumarate transport in Escherichia coli by an fnr-dependent dicarboxylate uptake system which is different from the aerobic dicarboxylate uptake system

Anaerobic fumarate transport in Escherichia coli by an fnr-dependent dicarboxylate uptake system which is different from the aerobic dicarboxylate uptake system

Identification of a third secondary carrier (DcuC) for anaerobic C4-dicarboxylate transport in Escherichia coli: roles of the three Dcu carriers in uptake and exchange

Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor σ E in Salmonella enterica serovar Typhimurium

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