Structural plasticity among glutathione transferase Phi members: natural combination of catalytic residues confers dual biochemical activities.

摘要: The glutathione transferase (GST) gene family is divided into 14 classes in photosynthetic organisms. Among them, the Phi class (GSTF) composed of a large number genes that are often induced response to environmental constraints due their ability detoxify xenobiotics, peroxidase activity and involvement biosynthesis and/or transport secondary metabolites. However, exact functions GSTFs from many plants including Populus trichocarpa unknown. Here, following GSTF1 characterization, we have performed comparative analysis seven other found poplar by systematically evaluating biochemical enzymatic properties corresponding recombinant proteins variants mutated for active site residues determining three-dimensional structures several representatives. Owing presence cysteine with pKa value around 5 site, GSTF3, F7, F8 displayed thiol addition usual activities. From structural analyses, it appeared these dual originate existence certain variability β1-α1 loop. This allows positioning at proximity molecule, which itself remains unchanged GSTF structures. These results highlight promiscuity some changes isoforms during evolution generated functional diversity modifying profile. Database Structural data available PDB under accession numbers 5EY6, 5F05, 5F06, 5F07.