1LM1: Structural Studies On The Synchronization Of Catalytic Centers In Glutamate Synthase: Native Enzyme

Citation:
Abstract
The complex iron-sulfur flavoprotein glutamate synthase (GltS) plays a prominent role in ammonia assimilation in bacteria, yeasts, and plants. GltS catalyzes the formation of two molecules of l-glutamate from 2-oxoglutarate and l-glutamine via intramolecular channeling of ammonia. GltS has the impressive ability of synchronizing its distinct catalytic centers to avoid wasteful consumption of l-glutamine. We have determined the crystal structure of the ferredoxin-dependent GltS in several ligation and redox states. The structures reveal the crucial elements in the synchronization between the glutaminase site and the 2-iminoglutarate reduction site. The structural data combined with the catalytic properties of GltS indicate that binding of ferredoxin and 2-oxoglutarate to the FMN-binding domain of GltS induce a conformational change in the loop connecting the two catalytic centers. The rearrangement induces a shift in the catalytic elements of the amidotransferase domain, such that it becomes activated. This machinery, over a distance of more than 30 A, controls the ability of the enzyme to bind and hydrolyze the ammonia-donating substrate l-glutamine.
PDB ID: 1LM1Download
MMDB ID: 20244
PDB Deposition Date: 2002/4/30
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1LM1: monomeric; determined by author
Molecular Components in 1LM1
Label Count Molecule
Protein (1 molecule)
1
Ferredoxin-dependent Glutamate Synthase
Molecule annotation
Chemicals (4 molecules)
1
2
2
1
3
1
* Click molecule labels to explore molecular sequence information.

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