Disease relevance of ECs3331

• When expressed in Escherichia coli, gonococcal NarQ and chimaeras of E. coli and gonococcal NarQ are ligand-insensitive and constitutively active: a "locked-on" phenotype [1].
• In contrast, Neisseria gonorrhoeae responds only to nitrite: it expresses only NarQ-NarP [2].
• Biochemical Society Special Lecture. Nitrate- and nitrite-responsive sensors NarX and NarQ of proteobacteria [3].

High impact information on ECs3331

• Response to culture aeration mediated by the nitrate and nitrite sensor NarQ of Escherichia coli K-12 [4].
• When nitrate is present, the NarX and NarQ sensor-transmitter proteins function to activate the response-regulator protein, NarL, which in turn binds to its DNA-recognition sites to modulate gene expression [5].
• Transcription initiation from the Escherichia coli napF operon control region is activated by the Fnr protein in response to anaerobiosis and by the NarQ-NarP two-component regulatory system in response to nitrate or nitrite [6].
• Although both NarX and NarQ are known to detect the two environmental signals nitrate and nitrite, little is known regarding the sensitivity and selectivity of ligand for detection or activation of the sensor-transmitters [7].
• NarX and NarQ each contain a conserved histidine residue that corresponds to the site of autophosphorylation of other sensor-transmitter proteins [8].

Chemical compound and disease context of ECs3331

• Mutagenesis experiments have revealed residues in E. coli NarQ that are essential for nitrate and nitrite sensing [2].

Biological context of ECs3331

• The NarX and NarQ proteins with amino acid substitutions at the first conserved histidine position were also unable to dephosphorylate NarL-phosphate in vitro [8].
• Phosphorylation and dephosphorylation of the NarQ, NarX, and NarL proteins of the nitrate-dependent two-component regulatory system of Escherichia coli [9].

Associations of ECs3331 with chemical compounds

• Thus, the NarQ sensor responds to aeration as well as to nitrate and nitrite [4].
• The conserved histidine and asparagine residues are essential for NarX and NarQ function, and this suggests that other two-component sensor-transmitter proteins may function in a similar fashion [8].
• Each protein transferred its phosphoryl group to purified NarL protein, although 'NarQ-phosphate catalyzed the transfer reaction at an apparently much faster rate than did 'NarX-phosphate [9].

References