Probably involved in nitrogen metabolism via ammonium assimilation. Catalyzes the ATP-dependent biosynthesis of glutamine from glutamate and ammonia. ATP + L-glutamate + NH4(+) = ADP + H(+) + L-glutamine + phosphate Binds 2 Mg(2+) ions per subunit. 12-fold increase in the presence of 2-oxoglutarate. Up to 18-fold increase in the presence of 2-oxoglutarate and GlnK1 or GlnK2. Inhibited by AMP and glutamine. Homododecamer (PubMed:23069245). Interacts with the nitrogen regulatory proteins GlnK1 and GlnK2 in the presence of 2-oxoglutarate (PubMed:23069245). Belongs to the glutamine synthetase family.