Differential roles of the Escherichia coli fumarases and fnr-dependent expression of fumarase B and aspartase

Woods, Sally A.

doi:10.1016/0378-1097(87)90165-0

Cited by 33 publications

(76 citation statements)

References 11 publications

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“…Similar observations were made for several other TCA cycle genes, including gltA, mdh, fumA and icd Woods and Guest, 1994;Park and Gunsalus, 1995;Park et al, 1995b;Chao et al, 1997), as well as for some respiratory pathway genes, frdABCD, dmsABC and narGHJI (Jones and Gunsalus, 1987;Li and DeMoss, 1988;Cotter and Gunsalus, 1989;reviewed in Gunsalus and Park, 1994). The molecular basis for this ArcA-and Fnr-independent control is not well understood, but it may be related to minor effects of DNA supercoiling (Axley and Stadtman, 1988).…”

Section: Fnr Acts As a Negative Regulator Of Sdhc Promoter Expressionsupporting

confidence: 59%

Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB ) gene expression in Escherichia coli

Shen

Gunsalus

1997

Molecular Microbiology

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SummarySuccinate dehydrogenase (sdhCDAB ) gene expression in Escherichia coli is negatively regulated by the arcA and fnr gene products during anaerobic cell growth conditions. The controlled synthesis of this sole membrane-bound enzyme of the tricarboxylic acid cycle allows optimal participation in the aerobic electron transport pathway for the generation of energy via oxidative phosphorylation reactions. To understand how ArcA participates in the anaerobic repression of sdhCDAB expression, a family of sdhC-lacZ fusions was constructed and analysed in vivo. DNase I footprint and gel shift assays using purified ArcA protein revealed the location of four distinct and independent ArcA binding sites in the sdhC promoter region. ArcA sites, designated sites 1 and 2, are centred at ¹205 bp and ¹119 bp upstream of the sdhC promoter, respectively, whereas ArcA site 3 overlaps the ¹35 and ¹10 regions of the sdhC promoter. A fourth ArcA site is centred at þ 257 bp downstream of the sdhC promoter. They are bound with differing affinity by ArcA and ArcA phosphate. The in vivo studies, in combination with the in vitro studies, indicate that ArcA site 3 is necessary and sufficient for the ArcA-dependent repression of sdhC gene expression, while the DNA region containing ArcA site 2 contributes to maximal gene expression. The DNA-containing ArcA sites 1 and 4 provide minor roles in the ArcA regulation of sdhC expression. Lastly, the Fnr-dependent control of sdhCDAB gene expression was shown to occur independently of the ArcA and to require DNA sequences near the start of sdhC transcription.

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Section: Fnr Acts As a Negative Regulator Of Sdhc Promoter Expressionsupporting

confidence: 59%

Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB ) gene expression in Escherichia coli

Shen

Gunsalus

1997

Molecular Microbiology

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“…Since the ArcA and/or the Fnr proteins are known to regulate several TCA cycle genes, including the sdhCDAB, mdh, gltA, acnA, and fumAC genes, in E. coli in response to anaerobiosis (6,8,(16)(17)(18)(19)27), we examined the effects of arcA and fnr gene deletions on sucA-lacZ and sdhCDAB-sucA-lacZ expression (Table 4). In neither the arcA strain nor the fnr strain did sucA-lacZ expression vary significantly compared to that of the wild-type strain grown under aerobic or anaerobic conditions.…”

Section: Resultsmentioning

confidence: 99%

“…Effect of iron availability on sucA-lacZ expression. Cellular iron levels have been shown to affect the expression of several TCA cycle genes including acnA and fumC (17,27). To determine if the iron limitation or iron excess condition affects sucABCD expression, cells containing the sucA-lacZ fusion were grown in minimal glucose medium under conditions previously used for the fumC studies (17).…”

Section: Resultsmentioning

confidence: 99%

Aerobic regulation of the sucABCD genes of Escherichia coli, which encode alpha-ketoglutarate dehydrogenase and succinyl coenzyme A synthetase: roles of ArcA, Fnr, and the upstream sdhCDAB promoter

1997

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The sucABCD genes of Escherichia coli encode subunits for two enzymes of the tricarboxylic acid (TCA) cycle, ␣-ketoglutarate dehydrogenase (sucAB) and succinyl coenzyme A synthetase (sucCD). To examine how these genes are expressed in response to changes in oxygen and carbon availability, a set of sucA-lacZ, sucC-lacZ, sdhCDAB-sucA-lacZ, and sdhC-lacZ fusions were constructed and analyzed in vivo. While the expression of a sucA-lacZ fusion was low under all cell growth conditions tested, the expression of the sucA gene from the upstream sdhC promoter was considerably higher and varied by up to 14-fold depending on the carbon substrate used. Expression of the sdhCDAB-sucA-lacZ fusion varied by fourfold in response to oxygen. In contrast, no expression was seen from a sucC-lacZ reporter fusion, indicating that no promoter immediately precedes the sucCD genes. Taken together, these findings demonstrate that the oxygen and carbon control of sucABCD gene expression occurs by transcriptional regulation of the upstream sdhC promoter. The weaker sucA promoter provides an additional low constitutive level of sucABCD gene expression to supplement transcription from the sdhC promoter. The negative control of sucABCD gene expression seen under anaerobic conditions, like that for the sdhCDAB genes, is provided by the arcA and fnr gene products. These findings establish that the differential expression of eight genes for three of the TCA cycle enzymes in E. coli is controlled from one regulatory element.The two tricarboxylic acid (TCA) cycle enzymes in Escherichia coli, ␣-ketoglutarate dehydrogenase and succinyl coenzyme A synthetase (succinyl-CoA synthetase), are encoded by thesucAB and sucCD genes, respectively (4). ␣-Ketoglutarate dehydrogenase catalyzes the oxidative decarboxylation of ␣-ketoglutarate to generate succinyl-CoA and carbon dioxide, along with the production of NADH plus H ϩ (20). SuccinylCoA synthetase catalyzes the interconversion of succinyl-CoA and succinate, and this interconversion is accompanied by the production or hydrolysis of GTP (10, 15). Both TCA cycle enzymes participate in the cyclic flow of carbon from acetylCoA to carbon dioxide during aerobic cell growth conditions (4). This process provides reducing equivalents in the form of NADH for subsequent use in electron transport-linked phosphorylation reactions. Succinyl-CoA synthetase also participates in the noncyclic or branched pathway operative during anaerobic cell growth conditions to provide carbon intermediates for cell biosynthetic reactions (10, 15). The results of enzyme assays and two-dimensional protein gel electrophoresis studies indicate that the cellular synthesis of ␣-ketoglutarate dehydrogenase is suppressed by anaerobiosis and glucose and is induced by acetate or other oxidized carbon sources (1,5,24).The sucABCD genes are located at 16.7 min in the E. coli chromosome near the genes for two other TCA cycle enzymes, succinate dehydrogenase (sdhCDAB) and citrate synthase (gltA) (Fig. 1) (25). Little information is available concer...

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“…E. coli possesses two of these fumarases: FumA and FumB. FumA accounts for about 80% of the fumarase activity when E. coli grows aerobically, whereas FumB is expressed only under anaerobic conditions and functions in the fermentative pathway that leads to the production of succinate (Yumoto & Tokushige, 1988;Woods & Guest, 1987). It seems unlikely that an obligate aerobe such as B. japonicum possesses a functional FumB homologue.…”

Section: Alternative Fumarase Activity and Physiological Role Of The mentioning

confidence: 99%

“…FumC accounts for up to 25% of the fumarase activity in aerobically grown E. coli cells. The respective gene is expressed under both aerobic and anaerobic conditions, and its weak promoter is not responsive to environmental changes (Woods & Guest, 1987). The substrate affinity of the E. coli FumC protein, like that of FumA, is higher for fumarate than for L-malate, suggesting a role in the TCA cycle (Woods et al, 1988b).…”

Section: Alternative Fumarase Activity and Physiological Role Of The mentioning

confidence: 99%

Cloning, sequencing, and mutational analysis of the Bradyrhizobium japonicum fumC-like gene: evidence for the existence of two different fumarases

Acuña

Ebeling

Hennecke

1991

Journal of General Microbiology

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The Bradyrhizobium japonicum fumarase gene (frrmC-like) was cloned and sequenced, and a fumC deletion mutant was constructed. This mutant had a Nod+ Fix+ phenotype in symbiosis with the host plant, soybean, and growth in minimal medium with fumarate as sole carbon source was also not affected. The cloned B. japonicum fumC gene fully complemented an Escherichia cofi Fum-mutant, strain JH400, for growth in minimal medium with fumarate. The predicted amino acid sequence of the FumC protein showed strong similarity to the E. cofi FumC protein, Bacillus subtifis CitG protein, Saccharomyces cereuisiae Fuml protein, and the mammalian fumarases. The B.japonicum FumC protein accounted for about 40% of the total fumarase activity in aerobically grown cells. The remaining 60% was ascribed to a temperature-labile fumarase. These data suggest that B. japonicum possesses two different fumarase isoerizymes, one of which is encoded by fumC. Besides E. cofi, which has three fumarases, B. japonicum is thus the second bacterium for which there is genetic evidence for the existence of more than one fumarase.

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Differential roles of the Escherichia coli fumarases and fnr-dependent expression of fumarase B and aspartase

Cited by 33 publications

References 11 publications

Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB ) gene expression in Escherichia coli

Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB ) gene expression in Escherichia coli

Aerobic regulation of the sucABCD genes of Escherichia coli, which encode alpha-ketoglutarate dehydrogenase and succinyl coenzyme A synthetase: roles of ArcA, Fnr, and the upstream sdhCDAB promoter

Cloning, sequencing, and mutational analysis of the Bradyrhizobium japonicum fumC-like gene: evidence for the existence of two different fumarases

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