Reaction: 2 L-glutamate + 2 oxidized ferredoxin = L-glutamine + 2-oxoglutarate + 2 reduced ferredoxin + 2 H+ (overall reaction)
(1a) L-glutamate + NH3 = L-glutamine + H2O
(1b) L-glutamate + 2 oxidized ferredoxin + H2O = NH3 + 2-oxoglutarate + 2 reduced ferredoxin + 2 H+
Other name(s): ferredoxin-dependent glutamate synthase; ferredoxin-glutamate synthase; glutamate synthase (ferredoxin-dependent)
Systematic name: L-glutamate:ferredoxin oxidoreductase (transaminating)
Comments: Binds a [3Fe-4S] cluster as well as FAD and FMN. The protein is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 18.104.22.168, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate. The NH3 is channeled through a 24 Å channel in the active protein. No hydrolysis of glutamine takes place without ferredoxin and 2-oxoglutarate being bound to the protein [5,6].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 62213-56-3
1. Galván, F., Márquez, A.J. and Vega, J.M. Purification and molecular properties of ferredoxin-glutamate synthase from Chlamydomonas reinhardii. Planta 162 (1984) 180-187.
2. Lea, P.J. and Miflin, B.J. Alternative route for nitrogen assimilation in higher plants. Nature (Lond.) 251 (1974) 614-616. [PMID: 4423889]
3. Ravasio, S., Dossena, L., Martin-Figueroa, E., Florencio, F.J., Mattevi, A., Morandi, P., Curti, B. and Vanoni, M.A. Properties of the recombinant ferredoxin-dependent glutamate synthase of Synechocystis PCC6803. Comparison with the Azospirillum brasilense NADPH-dependent enzyme and its isolated α subunit. Biochemistry 41 (2002) 8120-8133. [PMID: 12069605]
4. Navarro, F., Martin-Figueroa, E., Candau, P. and Florencio, F.J. Ferredoxin-dependent iron-sulfur flavoprotein glutamate synthase (GlsF) from the cyanobacterium Synechocystis sp. PCC 6803: expression and assembly in Escherichia coli. Arch. Biochem. Biophys. 379 (2000) 267-276. [PMID: 10898944]
5. van den Heuvel, R.H., Ferrari, D., Bossi, R.T., Ravasio, S., Curti, B., Vanoni, M.A., Florencio, F.J. and Mattevi, A. Structural studies on the synchronization of catalytic centers in glutamate synthase. J. Biol. Chem. 277 (2002) 24579-24583. [PMID: 11967268]
6. van den Heuvel, R.H., Svergun, D.I., Petoukhov, M.V., Coda, A., Curti, B., Ravasio, S., Vanoni, M.A. and Mattevi, A. The active conformation of glutamate synthase and its binding to ferredoxin. J. Mol. Biol. 330 (2003) 113-128. [PMID: 12818206]