Disease relevance of glnA

• A direct relationship between increased glutamine synthetase activity and enhanced biosurfactant production was found in Pseudomonas aeruginosa grown in nitrate and Proteose Peptone media [1].
• It is suggested that the hut genes of P. aeruginosa may be regulated in the same way as in Klebsiella aerogenes, by induction by urocanate and activation by either the cyclic AMP-dependent activator protein or by glutamine synthetase [2].

High impact information on glnA

• However, the rpoN mutants were glutamine auxotrophs and were defective in glutamine synthetase, indicating defects in nitrogen assimilation [3].
• A chloramphenicol-tolerant strain showed a twofold increase in biosurfactant production and glutamine synthetase activity [1].
• With immunological techniques, it could be demonstrated that the glutamine auxotrophs form an inactive glutamine synthetase protein which is regulated by glutamine or a product derived from it in a way similar to other nitrogen-controlled proteins [4].
• Nitrogen control in Pseudomonas aeruginosa: mutants affected in the synthesis of glutamine synthetase, urease, and NADP-dependent glutamate dehydrogenase [5].
• Furthermore, methionine-sulfoximine, which prevented the intracellular glutamine formation from ammonium via inhibition of glutamine synthetase, relieved the inhibition of urea uptake by ammonium [6].

Biological context of glnA

• These revertants were different from both the wild-type strain and the GlnR- mutant with respect to the regulation of the synthesis of glutamine synthetase, urease, and NADP-dependent glutamate dehydrogenase (GlnRc phenotype) [5].

Associations of glnA with chemical compounds

• In contrast to the wild-type strain, these mutants appeared to be unable to derepress the formation of glutamine synthetase and urease under nitrogen-limited growth conditions, whereas NADP-dependent glutamate dehydrogenase became derepressed [5].
• The operation of a nitrogen control mechanism in the regulation of the allantoin-degrading enzymes could be demonstrated with glutamine synthetase-negative mutants, which showed elevated synthesis and escape from catabolite repression when growth was limited for glutamine [7].
• The key metabolite in this process appears to be glutamine or a product derived from it, since ammonia and glutamate did not repress urease and histidase synthesis in a mutant lacking glutamine synthetase activity when growth was limited for glutamine [8].

References