eng URI http://hdl.handle.net/10795/2633 ένζυμο βιοτεχνολογία διαγονιδιακό φυτό The plant tau class glutathione transferases (GSTs) play important roles in biotic and abiotic stress tolerance in crops and weeds. In this study, we systematically examined the catalytic and structural features of a GST isoenzyme from Glycine max (GmGSTU10-10). GmGSTU10-10 is a unique isoenzyme in soybean that is specifically expressed in response to biotic stress caused by soybean mosaic virus (SMV) infections. GmGSTU10-10 was cloned, expressed in Escherichia coli, purified and characterized. The results showed that GmGSTU10-10 catalyzes several different reactions and exhibits wide substrate specificity. Of particular importance is the finding that the enzyme shows high antioxidant catalytic function and acts as hydroperoxidase. In addition, its Km for GSH is significantly lower, compared to other plant GSTs, suggesting that GmGSTU10-10 is able to perform efficient catalysis under conditions where the concentration of reduced glutathione is low (e.g. oxidative stress). The crystal structure of GmGSTU10-10 was solved by molecular replacement at 1.6 Å resolution in complex with glutathione sulfenic acid (GSOH). Structural analysis showed that GmGSTU10-10 shares the same overall fold and domain organization as other plant cytosolic GSTs; however, major variations were identified in helix H9 and the upper part of helix H4 that affect the size of the active site pockets, substrate recognition and the catalytic mechanism. The results of the present study provide new information into GST diversity and give further insights into the complex regulation and enzymatic functions of this plant gene superfamily. 12 pp. LOMv1.0 creator LOMv1.0 publisher LOMv1.0 Project Final Beneficiary LOMv1.0 Project Executing Organisation 2014-12-03 Digital Library of the Operational Programme "Education and Lifelong Learning" abstract types Text Biotic and abiotic stress Enzyme catalysis Herbicide detoxification Tau class GST X-ray structure http://www.sciencedirect.com/science/article/pii/S1570963914003136 2843759 application/pdf http://repository.edulll.gr/edulll/bitstream/10795/2633/2/2633_Paper%2010.pdf URI http://hdl.handle.net/10795/2633 LOMv1.0creator 2016-04-14T07:12:58Z LOMv1.0validator 2016-04-14T07:12:58Z LOMv1.0 gre no no Copyright EYD-EPEDBM (Operational Programme "Education and Lifelong Learning")