Structure, Evolution and Functional Roles of Plant Glutathione Transferases

Plant cytosolic glutathione transferases (EC 2.5.1.18, GSTs) are essential enzymes involved in multiple and diverse functions which are crucial to xenobiotic detoxification, hormone signalling, redox homeostasis, plant metabolism, growth regulation and adaptation to abiotic and biotic stresses. GSTs are capable of catalysing the conjugation of reduced glutathione (γ-L-Glu-L-Cys-Gly; GSH), via the sulphydryl group, to electrophilic centres on a vast number of molecules, both endogenous and xenobiotic, including herbicides, leading to their detoxification. Recent progress of plant proteomics, genomics and transcriptomics projects has allowed the identification, classification and evolutionary analysis of a large number of GST isoenzymes and has provided new knowledge and insights into their in planta function and catalytic role. This chapter focuses on plant GSTs and attempts to give an overview of their evolution, catalytic function and structural biology.