Article examining the mechanism of Glutathione synthetase, an enzyme that belongs to the glutathione synthetase ATP-binding domain-like superfamily. A variety of structural alignment methods were applied and four highly conserved residues of human glutathione synthetase (Glu-144, Asn-146, Lys-305, and Lys-364) were identified in the binding site. The function of these was studied by experimental and computational site-directed mutagenesis.
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Article examining the mechanism of Glutathione synthetase, an enzyme that belongs to the glutathione synthetase ATP-binding domain-like superfamily. A variety of structural alignment methods were applied and four highly conserved residues of human glutathione synthetase (Glu-144, Asn-146, Lys-305, and Lys-364) were identified in the binding site. The function of these was studied by experimental and computational site-directed mutagenesis.
Abstract: Glutathione synthetase is an enzyme that belongs to the glutathione synthetase ATP-binding domain-like superfamily. It catalyzes the second step in the biosynthesis of glutathione from γ-glutamylcysteine and glycine in an ATP-dependent manner. Glutathione synthetase has been purified and sequenced from a variety of biological sources; still, its exact mechanism is not fully understood. A variety of structural alignment methods were applied and four highly conserved residues of human glutathione synthetase (Glu-144, Asn-146, Lys-305, and Lys-364) were identified in the binding site. The function of these was studied by experimental and computational site-directed mutagenesis. The three-dimensional coordinates for several human glutathione synthetase mutant enzymes were obtained using molecular mechanics and molecular dynamics simulation techniques, starting from the reported crystal structure of human glutathione synthetase. Consistent with circular dichroism spectroscopy, our results showed no major changes to overall enzyme structure upon residue mutation. However, semiempirical calculations revealed that ligand binding is affected by these mutations. The key interactions between conserved residues and ligands were detected and found to be essential for enzymatic activity. Particularly, the negatively charged Glu-144 residue plays a major role in catalysis.
Publication Title:
Journal of Biological Chemistry
Volume:
279
Issue:
21
Page Start:
22412
Page End:
22421
Pages:
10
Peer Reviewed:
Yes
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Dinescu, Adriana; Cundari, Thomas R., 1964-; Bhansali, Vikas S.; Luo, Jia-Li & Anderson, Mary E.Function of Conserved Residues of Human Glutathione Synthetase: Implications for the ATP-Grasp Enzymes,
article,
May 21, 2004;
[Rockville, Maryland].
(https://digital.library.unt.edu/ark:/67531/metadc1871056/:
accessed February 13, 2025),
University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu;
crediting UNT College of Science.