Discrimination between structurally related ligands nitrate and nitrite controls autokinase activity of the NarX transmembrane signal transducer of <i>Escherichia coli</i> K‐12

Williams, Stanly B.; Stewart, Valley

doi:10.1046/j.1365-2958.1997.6262002.x

Cited by 61 publications

(99 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The host strain VJS11210 (Table 1) carries the nitrate-inducible W(narGlacZ) gene fusion in monocopy at the bacteriophage l attachment site, null alleles for both narX and narQ, and the pcnB1 mutation that reduces ColE1-type plasmid copy number to approximately one per cell (Williams & Stewart, 1997b). WT and mutant narX and narQ genes are cloned into the compatible medium copy number vectors pHG165 (Stewart et al, 1986) and pSU18 (Bartolomé et al, 1991).…”

Section: Methodsmentioning

confidence: 99%

“…We additionally examined two different mutational alterations, both within the transmembrane signalling module, that affect NarX nitrate response. The R54K substitution at the nitrate-binding site results in the uninducible phenotype (Williams & Stewart, 1997b), whereas the dual S43C plus T145C substitutions result in the constitutive phenotype (T. N. Huynh and V. Stewart, unpublished). Overall, these tests confirm that the hybrid proteins were stable and functional.…”

Section: Narx and Narq Homomeric Interactionmentioning

confidence: 99%

“…NarX is specialized, responding preferentially to nitrate and displaying kinetic preference for NarL, whereas NarQ is generalized, responding to both nitrate and nitrite and phosphorylating both response regulators with similar kinetics Williams & Stewart, 1997b) (Fig. 1b).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sensor–response regulator interactions in a cross-regulated signal transduction network

2015

Self Cite

View full text Add to dashboard Cite

Two-component signal transduction involves phosphoryl transfer between a histidine kinase sensor and a response regulator effector. The nitrate-responsive two-component signal transduction systems in Escherichia coli represent a paradigm for a cross-regulation network, in which the paralogous sensor-response regulator pairs, NarX-NarL and NarQ-NarP, exhibit both cognate (e.g. NarX-NarL) and non-cognate (e.g. NarQ-NarL) interactions to control output. Here, we describe results from bacterial adenylate cyclase two-hybrid (BACTH) analysis to examine sensor dimerization as well as interaction between sensor-response regulator cognate and non-cognate pairs. Although results from BACTH analysis indicated that the NarX and NarQ sensors interact with each other, results from intragenic complementation tests demonstrate that they do not form functional heterodimers. Additionally, intragenic complementation shows that both NarX and NarQ undergo intermolecular autophosphorylation, deviating from the previously reported correlation between DHp (dimerization and histidyl phosphotransfer) domain loop handedness and autophosphorylation mode. Results from BACTH analysis revealed robust interactions for the NarX-NarL, NarQ-NarL and NarQ-NarP pairs but a much weaker interaction for the NarX-NarP pair. This demonstrates that asymmetrical cross-regulation results from differential binding affinities between different sensor-regulator pairs. Finally, results indicate that the NarL effector (DNA-binding) domain inhibits NarX-NarL interaction. Missense substitutions at receiver domain residue Ser-80 enhanced NarX-NarL interaction, apparently by destabilizing the NarL receiver-effector domain interface.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Narx and Narq Homomeric Interactionmentioning

confidence: 99%

See 1 more Smart Citation

Sensor–response regulator interactions in a cross-regulated signal transduction network

2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…In E. coli the presence of nitrate is sensed by paralogous twocomponent systems NarXL and NarPQ (Stewart, 1994). The membrane-bound sensors NarX and NarP perceive the presence of nitrate and nitrite in the environment (Lee et al, 1999;Rabin & Stewart, 1992, 1993Williams & Stewart, 1997). These sensors then act to control the phosphorylation state of the regulators NarL and NarP (Darwin & Stewart, 1996;Yamamoto et al, 2005), and there is a complex exchange of information between the sensors and the regulators to allow fine control of targetgene expression in response to nitrate and nitrite.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Escherichia coli K-12 ydhYVWXUT operon: regulation by FNR, NarL and NarP

Partridge

Browning

et al. 2008

Microbiology

View full text Add to dashboard Cite

In Escherichia coli K-12 the expression of many genes is controlled by the oxygen-responsive transcription factor FNR and the nitrate-and nitrite-responsive two-component systems NarXL and NarPQ. Here, the ydhY gene is shown to be the first gene of a six-gene operon (ydhYVWXUT) that encodes proteins predicted to be components of an oxidoreductase. Mapping the ydhY-T transcript start and site-directed mutagenesis confirmed that the ydhY-T genes are transcribed from an FNR-dependent class II promoter and showed that the FNR site is centred at "42.5. In the presence of nitrate or nitrite, NarXL and NarPQ repressed ydhY-T expression. Analysis of the DNA sequence of the ydhY promoter region (PydhY) revealed the presence of four heptameric sequences similar to NarL/P binding sites centred at "42, "16, +6 and +15. The latter heptamers are arranged as a 7-2-7 inverted repeat, which is required for recognition by NarP. Accordingly, NarP protected the 7-2-7 region in DNase I footprints, and mutation of either heptamer +6 or heptamer +15 impaired nitrite-mediated repression, whereas mutation of heptamer "42 and heptamer "16 did not affect the response to nitrite. The NarL protein also protected the 7-2-7 region, but in contrast to NarP, the NarL footprint extended further upstream to encompass the "16 heptamer. The extended NarL footprint was consistent with the presence of multiple NarL-PydhY complexes in gel retardation assays. Mutation of heptamer "42, which is located within the FNR binding site, or heptamer +6 (but not heptamers "16 or +15) impaired nitrate-mediated repression. Thus, although the region of the ydhY-T promoter containing the "16 and +15 heptamers was recognized by NarL in vitro, mutation of these heptamers did not affect NarL-mediated repression in vivo.

show abstract

“…Transcription of this operon requires the FNR, NarX and NarL proteins. The NarX protein is the histidine protein kinase and the NarL protein is the response regulator in the transcriptional activation of the narGHJZ operon (Schroder et al, 1994;Walker & DeMoss, 1993 ;Williams & Stewart, 1997). The NarX protein, besides transferring the phosphate after autophosphorylation to the NarL protein, also serves as a phosphatase of NarL-P to modulate the level of narGHJ1 operon expression (Schroder et al, 1994;Walker & DeMoss, 1993).…”

Section: Introductionmentioning

confidence: 99%

Transcriptional regulation of molybdoenzyme synthesis in Escherichia coli in response to molybdenum: ModE-molybdate, a repressor of the modABCD (molybdate transport) operon is a secondary transcriptional activator for the hyc and nar operons

Self¹,

Grunden²,

Hasona³

et al. 1999

Microbiology

View full text Add to dashboard Cite

Escherichia coli growing under anaerobic conditions produces several molybdoenzymes, such as formate hydrogenlyase (formate to H, and CO, ; hyc and fdhf genes) and nitrate reductase (narGHII genes). Synthesis of these molybdoenzymes, even in the presence of the cognate transcriptional activators and effectors, requires molybdate in the medium. Besides the need for molybdopterin cofactor synthesis, molybdate is also required for transcription of the genes encoding these molybdoenzymes. In E. coli, ModE was previously identified as a repressor controlling transcription of the operon encoding molybdate transport components (modABCD). In this work, the ModE protein was also found to be a required component in the activation of hyc-lacZ to an optimum level, but only in the presence of molybdate. Mutant ModE proteins which are molybdate-independent for repression of modA-lacZ also restored hyc-lacZ expression to the wild-type level even in the absence of molybdate. Nitrate-dependent enhancement of transcription of narX-lacZ was completely abolished in a mod€ mutant. Nitrate-response by narG-lacZ and narK-lacZ was reduced by about 50% in a mod€ mutant. DNase I footprinting experiments revealed that the ModE protein binds the hyc promoter DNA in the presence of molybdate. ModE-molybdate also protected DNA in the intergenic region between narXL and narK from DNase I hydrolysis. DNA sequences (5' TAYAT 3' and 5' GTTA 3') found in ModE-molybdate-protected modABCD operator DNA were also found in the ModE-molybdate-protected region of hyc promoter DNA (5' GTTA-7 bp-CATAT 3') and narX-narK intergenic region (5' GTTA-7 bp-TACAT 3'). Based on these results, a working model is proposed in which ModE-molybdate serves as a secondary transcriptional activator of both the hyc and narXL operons which are activated primarily by the transcriptional activators, FhlA and NarL, respectively.

show abstract

Discrimination between structurally related ligands nitrate and nitrite controls autokinase activity of the NarX transmembrane signal transducer of Escherichia coli K‐12

Cited by 61 publications

References 50 publications

Sensor–response regulator interactions in a cross-regulated signal transduction network

Sensor–response regulator interactions in a cross-regulated signal transduction network

Characterization of the Escherichia coli K-12 ydhYVWXUT operon: regulation by FNR, NarL and NarP

Transcriptional regulation of molybdoenzyme synthesis in Escherichia coli in response to molybdenum: ModE-molybdate, a repressor of the modABCD (molybdate transport) operon is a secondary transcriptional activator for the hyc and nar operons

Contact Info

Product

Resources

About