Characterization of a gamma-glutamyl kinase from Escherichia coli that confers proline overproduction and osmotic tolerance.
Mutation(s) in the proBA operon of Escherichia coli confers proline overproduction and enhanced osmotic tolerance in enteric bacteria (L. N. Csonka, Mol. Gen. Genet. 182:82-86, 1981; M. J. Mahan and L. N. Csonka, J. Bacteriol. 156:1249-1262, 1983). A glutamate-dependent ATPase assay was developed and used to determine proB-encoded gamma-glutamyl kinase activity in the absence of glutamate-gamma-semialdehyde dehydrogenase. This assay indicated that the feedback insensitivity of mutant gamma-glutamyl kinase was independent of glutamate-gamma-semialdehyde dehydrogenase. However, the capacity of glutamate-gamma-semialdehyde dehydrogenase from the osmotolerant mutant to interact with the kinase was altered in thermal stability, suggesting that mutations in both proB and proA may be required for osmotolerance.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D050698:Glutamate-5-Semialdehyde Dehydrogenase; D006358:Hot Temperature; D006877:Hydroxamic Acids / Q000378:metabolism; D009154:Mutation; D009876:Operon; D009996:Osmotic Fragility; D010770:Phosphotransferases / Q000378:metabolism*; D017851:Phosphotransferases (Carboxyl Group Acceptor); D011392:Proline / Q000096:biosynthesis*; D011489:Protein Denaturation; D013696:Temperature
D006877:Hydroxamic Acids; D011392:Proline; D000445:Aldehyde Oxidoreductases; D050698:Glutamate-5-Semialdehyde Dehydrogenase; D010770:Phosphotransferases; D017851:Phosphotransferases (Carboxyl Group Acceptor); C020650:glutamate 5-kinase; D000251:Adenosine Triphosphatases