Redox regulated methionine oxidation of Arabidopsis thaliana glutathione transferase Phi9 induces H-site flexibility
| Autor: | Leonardo Astolfi Rosado, Khadija Wahni, Didier Vertommen, Inge Van Molle, Joris Messens, Maria-Armineh Tossounian |
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| Přispěvatelé: | Department of Bio-engineering Sciences, Faculty of Sciences and Bioengineering Sciences, Structural Biology Brussels |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Protein Folding Full‐Length Papers Entropy Arabidopsis Biochemistry Protein Structure Secondary 03 medical and health sciences chemistry.chemical_compound Methionine steady-state kinetics Transferase Molecular Biology Glutathione Transferase chemistry.chemical_classification Arabidopsis Proteins Chemistry Methionine sulfoxide Glutathione peroxidase Hydrogen Peroxide Glutathione 030104 developmental biology Enzyme redox methionine sulfoxide reductase Methionine sulfoxide reductase Thermodynamics X-ray structure Oxidation-Reduction Cysteine |
| Popis: | Glutathione transferase enzymes help plants to cope with biotic and abiotic stress. They mainly catalyze the conjugation of glutathione (GSH) onto xenobiotics, and some act as glutathione peroxidase. With X‐ray crystallography, kinetics, and thermodynamics, we studied the impact of oxidation on Arabidopsis thaliana glutathione transferase Phi 9 (GSTF9). GSTF9 has no cysteine in its sequence, and it adopts a universal GST structural fold characterized by a typical conserved GSH‐binding site (G‐site) and a hydrophobic co‐substrate‐binding site (H‐site). At elevated H(2)O(2) concentrations, methionine sulfur oxidation decreases its transferase activity. This oxidation increases the flexibility of the H‐site loop, which is reflected in lower activities for hydrophobic substrates. Determination of the transition state thermodynamic parameters shows that upon oxidation an increased enthalpic penalty is counterbalanced by a more favorable entropic contribution. All in all, to guarantee functionality under oxidative stress conditions, GSTF9 employs a thermodynamic and structural compensatory mechanism and becomes substrate of methionine sulfoxide reductases, making it a redox‐regulated enzyme. |
| Databáze: | OpenAIRE |
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