Disease relevance of glnA

• Regulation of expression from the glnA promoter of Escherichia coli in the absence of glutamine synthetase [1].
• A plasmid containing this E. coli DNA fragment joined to another fragment carrying a cyanobacterial glnA gene (but no functional regulatory genes) was introduced into a Klebsiella pneumoniae mutant with a Gln-Ntr- phenotype, i.e., which could not derepress nitrogenase [2].
• Regulation of the synthesis of glutamine synthetase and of the arginine and glutamine transport systems (Ntr phenotype) in Salmonella have been shown to require two regulatory genes on the C-terminal side of the glnA gene (McFarland et al., 1981) [2].
• The poor growth of Rhodospirillum rubrum mutants lacking PII proteins is due to an excess of glutamine synthetase activity [3].
• Studies of Anabaena glnA gene activity in E. coli suggest that the cyanobacterial gene is not repressible and that the Anabaena 7120 glutamine synthetase is not adenylylated in E. coli [4].

High impact information on glnA

• The hybridization probe for the cyanobacterial gene was a recombinant plasmid containing the glnA gene from Escherichia coli K-12 [4].
• Some aspects of regulation were retained in haploid fusion strains despite the absence of glutamine synthetase, whereas other aspects required glutamine synthetase catalytic or regulatory activity or both [1].
• We isolated Escherichia coli strains carrying fusions of the beta-galactosidase structural gene to the promoter of the glutamine synthetase gene, with the aid of the Casadaban Mud1 (ApR, lac, cts62) phage [1].
• Mutations in the glnA region of the Escherichia coli chromosome due to Mu prophage insertion result in two phenotypic classes [5].
• Active site ligand stabilization of quaternary structures of glutamine synthetase from Escherichia coli [6].

Chemical compound and disease context of glnA

• In heterologous expression experiments, glnA2, glnA3, and glnA4, in contrast to glnA and glnII, were not capable of complementing the L: -glutamine auxotrophy of an Escherichia coli glnA mutant [7].
• Auto-inactivated EScherichia coli glutamine synthetase contains 1 eq each of L-methionine-S-sulfoximine phosphate and ADP and 2 eq of Mn2+ tightly bound to the active site of each subunit of the dodecameric enzyme (Maurizi, M. R., and Ginsburg, A. (1982) J. Biol. Chem. 257, 4271-4278) [6].
• In the dimorphic bacterium Caulobacter crescentus, ammonia assimilation occurs only via the combined action of the enzymes glutamine synthetase and glutamate synthase [8].

Biological context of glnA

• Polarity in the glnA operon: suppression of the reg- phenotype by rho mutations [9].
• The result underscores the importance of proper regulation of GS activity for cell growth [3].
• All of these results strongly imply that elevated GS activity is the causative basis for the poor growth seen in R. rubrum mutants lacking P(II) and presumably in mutants of some other organisms with similar genotypes [3].
• Thus, the tight binding of ligands to the subunit active site strengthens both intra- and inter-subunit bonding domains in dodecameric glutamine synthetase [6].

Associations of glnA with chemical compounds

• In this study, therefore, an extrinsic fluor is introduced into the adenylated glutamine synthetase by adenylating the enzyme with 2-aza-1,N6-ethenoadenosine triphosphate, a fluorescent analog of ATP [10].
• Previously, the catalytic action of unadenylated glutamine synthetase was elucidated by monitoring the intrinsic tryptophan fluorescence change accompanying substrate binding [10].
• Molecular analysis of two mutants from Lotus japonicus deficient in plastidic glutamine synthetase: functional properties of purified GLN2 enzymes [11].
• Both glutamate synthase and glutamine synthetase activities were subject to regulation by repression [8].
• Stereochemistry of binding of thiophosphate analogs of ATP and ADP to carbamate kinase, glutamine synthetase, and carbamoyl-phosphate synthetase [12].

Analytical, diagnostic and therapeutic context of glnA

• Heteroduplex analysis reveals 0.65 kbp of homology between the 7.5-kbp Anabaena 7120 fragment and an 11-kbp E. coli fragment that codes for E. coli glutamine synthetase [4].
• Scanning transmission electron microscopy of submolecular oligomers of stabilized glutamine synthetase from Escherichia coli [13].
• Proteins in crude extracts of the transductant were examined by a "Western blotting" procedure for the presence of B. subtilis or E. coli glutamine synthetase antigen; only the former was detected [14].
• Relationship between epitope density and immunoprecipitation of multivalent antigens by bivalent antibody: immunoprecipitation of adenylylated glutamine synthetase by anti-AMP antibodies [15].

References