1ofd | pdb_00001ofd

GLUTAMATE SYNTHASE FROM SYNECHOCYSTIS SP IN COMPLEX WITH 2-OXOGLUTARATE AT 2.0 ANGSTROM RESOLUTION

spinqualitylabelsall models 1ofd, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ofd is a 2 chain structure with sequence from Aphanocapsa sp. (strain n-1). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AKG, F3S, FMN Related: 1llw, 1llz, 1lm1, 1ofe Activity: Glutamate synthase (ferredoxin), with EC number 1.4.7.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Glutamate synthases (GltS) are crucial enzymes in ammonia assimilation in plants and bacteria, where they catalyze the formation of two molecules of L-glutamate from L-glutamine and 2-oxoglutarate. The plant-type ferredoxin-dependent GltS and the functionally homologous alpha subunit of the bacterial NADPH-dependent GltS are complex four-domain monomeric enzymes of 140-165 kDa belonging to the NH(2)-terminal nucleophile family of amidotransferases. The enzymes function through the channeling of ammonia from the N-terminal amidotransferase domain to the FMN-binding domain. Here, we report the X-ray structure of the Synechocystis ferredoxin-dependent GltS with the substrate 2-oxoglutarate and the covalent inhibitor 5-oxo-L-norleucine bound in their physically distinct active sites solved using a new crystal form. The covalent Cys1-5-oxo-L-norleucine adduct mimics the glutamyl-thioester intermediate formed during L-glutamine hydrolysis. Moreover, we determined a high resolution structure of the GltS:2-oxoglutarate complex. These structures represent the enzyme in the active conformation. By comparing these structures with that of GltS alpha subunit and of related enzymes we propose a mechanism for enzyme self-regulation and ammonia channeling between the active sites. X-ray small-angle scattering experiments were performed on solutions containing GltS and its physiological electron donor ferredoxin (Fd). Using the structure of GltS and the newly determined crystal structure of Synechocystis Fd, the scattering experiments clearly showed that GltS forms an equimolar (1:1) complex with Fd. A fundamental consequence of this result is that two Fd molecules bind consecutively to Fd-GltS to yield the reduced FMN cofactor during catalysis. The active conformation of glutamate synthase and its binding to ferredoxin.,van den Heuvel RH, Svergun DI, Petoukhov MV, Coda A, Curti B, Ravasio S, Vanoni MA, Mattevi A J Mol Biol. 2003 Jun 27;330(1):113-28. PMID:12818206 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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