An octameric prokaryotic glutamine synthetase from the haloarchaeon Haloferax mediterranei.
The glutamine synthetase (EC 6.3.1.2) from the haloarchaeon Haloferax mediterranei has been purified and characterized in order to understand the ammonium assimilation in haloarchaea. Based on sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel-filtration chromatography, the enzyme consists of eight subunits of 51.7 kDa, suggesting that this enzyme belongs to the glutamine synthetase type II. The purified enzyme has been characterized with respect to its optimum temperature (45 degrees C) and pH value (8.0). The optimal NaCl or KCl concentrations for the reaction were 0.5 and 0.25 M, respectively. The effect of l-methionine-d, l-sulphoximine and different divalent metal ions has also been tested. The glutamine synthetase presented here is unusual; it shows the typical characteristic of eukaryotic and soil bacteria glutamine synthetases.
Martínez-Espinosa
Rosa María
RM
División de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain.
Esclapez
Julia
J
Bautista
Vanesa
V
Bonete
María José
MJ
D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D019623:Haloferax mediterranei / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D008715:Methionine / Q000494:pharmacology; D008717:Methionine Sulfoximine / Q000494:pharmacology; D011189:Potassium Chloride / Q000737:chemistry; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013696:Temperature
D004791:Enzyme Inhibitors; D021122:Protein Subunits; D008717:Methionine Sulfoximine; D012965:Sodium Chloride; D011189:Potassium Chloride; D008715:Methionine; C083818:glutamine synthetase 2; D005974:Glutamate-Ammonia Ligase