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Ammonium ion is thought to bind to GS at the monovalent cation binding site for Tl(+) and Cs(+) ions. | Ammonium ion is thought to bind to GS at the monovalent cation binding site for Tl(+) and Cs(+) ions. | ||
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Revision as of 01:27, 7 December 2008
Contents |
Assignment 12: IVC: Ammonium Binding Site
Mapping the Ammonium binding site and explaining how it contributes to catalysis.
Chang, Yu-Wei and Kaushal, Pankaj.
BIOL 430: Biological Chemistry.
University of Maryland, Baltimore County (UMBC).
Script Exercises
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Exercise shows a backbone trace of Glutamate Synthase which allows the ligands inside ADP, P3S, Cl- and Mn2+ to be seen.
Isolates chain A of Glutamate Synthase and labels the ligands for easy identification.
Wire Structure of Active Site residues of chain A using information obtained from PDBsum entry for Glutamate Synthase.
Still picture of salt bridge between residue 63 of chain F and residue 319 of chain G. Bridge length is also provided in Angstroms.
Outline
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-- Work in Progress --
Glutamine synthetase (GS) catalyzes the ATP dependent condensation of glutamate and ammonia, producing, glutamine, ADP, and an inorganic phosphate group.
Glutamate + ATP + NH3 → Glutamine + ADP + phosphate
Ammonium ion is thought to bind to GS at the monovalent cation binding site for Tl(+) and Cs(+) ions.
References
1. Liaw, S-H, et.al.,Discovery of the ammonium substrate site on glutamine synthetase, a third cation binding site Protein Sci. 1995 4: 2358-2365[1]
2. Liaw SH, Eisenberg D. Structural model for the reaction mechanism of glutamine synthetase, based on five crystal structures of enzyme-substrate complexes. Biochemistry. 1994 Jan 25;33(3):675-81. [2]
