Probably involved in nitrogen metabolism via ammonium assimilation. Catalyzes the ATP-dependent biosynthesis of glutamine from glutamate and ammonia. Beta-glutamate is a much poorer substrate than alpha-glutamate. ATP + L-glutamate + NH4(+) = ADP + H(+) + L-glutamine + phosphate Binds 2 Mg(2+) ions per subunit. Feedback inhibited by glycine and alanine, and inhibited by low concentrations of methionine sulfoximine. Oligomer of 12 subunits arranged in the form of two hexagons. Belongs to the glutamine synthetase family.