Glutamate synthase: a fascinating pathway from L-glutamine to L-glutamate.
Glutamate synthase is a multicomponent iron-sulfur flavoprotein belonging to the class of N-terminal nucleophile amidotransferases. It catalyzes the conversion of L-glutamine and 2-oxoglutarate into two molecules of L-glutamate. In recent years the X-ray structures of the ferredoxin-dependent glutamate synthase and of the a subunit of the NADPH-dependent glutamate synthase have become available. Thanks to X-ray crystallography, it is now known that the ammonia reaction intermediate is transferred via an intramolecular tunnel from the amidotransferase domain to the synthase domain over a distance of about 32A. Although ammonia channeling is a recurrent theme for N-terminal nucleophile and triad-type amidotransferases, the molecular mechanisms of ammonia transfer and its control are different for each known amidotransferase. This review focuses on the intriguing mechanism of action and self-regulation of glutamate synthase with a special focus on the structural data.
van den Heuvel
R H H
RH
Department of Genetics and Microbiology, University of Pavia, Italy.
Curti
B
B
Vanoni
M A
MA
Mattevi
A
A
D020134:Catalytic Domain; D005970:Glutamate Synthase / Q000737:chemistry / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D008024:Ligands; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D015398:Signal Transduction
D008024:Ligands; D005973:Glutamine; D018698:Glutamic Acid; D005970:Glutamate Synthase