Plant glutathione S-transferase classification, structure and evolution

Glutathione S-transferases are multifunctional proteins involved in diverse intracellular events such as primary and secondary metabolisms, stress metabolism, herbicide detoxification and plant protection against ozone damages, heavy metals and xenobiotics. The plant glutathione S-transferase superfamily have been subdivided into eight classes. Phi, tau, zeta, theta, lambda, dehydroascorbate reductase and tetrachlorohydroquinone dehalogenase classes are soluble and one class is microsomal. Glutathione S-transferases are mostly soluble cytoplasmic enzymes. To date, the crystal structures of over 200 soluble glutathione S-transferases, present in plants, animals and bacteria have been resolved. The structures of glutathione S-transferase influence its function. Phylogenetic analysis suggests that all soluble glutathione S-transferases have arisen from an ancient progenitor gene, through both convergent and divergent pathways.