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. The activity of this enzyme could be controlled by adenylation under conditions of abundant glutamine. Oligomer of 12 subunits arranged in the form of two hexagons. Belongs to the glutamine synthetase family.