Description
Binds FMN, FAD, 2 [4Fe-4S] clusters and 1 [3Fe-4S] cluster. The reaction takes place in the opposite direction to that shown. The protein is composed of two subunits, α and β. The α subunit is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 3.5.1.2, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate (cf. EC 1.4.1.4, glutamate dehydrogenase [NADP+]). The β subunit transfers electrons to the cosubstrate. The NH3 is channeled through a 31 Å channel in the active protein. In the absence of the β subunit, coupling between the two domains of the α subunit is compromised and some ammonium can be produced. In the intact αβ complex, ammonia production only takes place as part of the overall reaction