InterPro domain: IPR034347

This entry represents the C-terminal alpha helical domain found in the Phi subfamily (also known as GSTF) of the glutathione S-transferase (GST) family. GSTF had long been regarded as plant specific but has also been found in basidiomycete fungi [ 1 ].

The class Phi GST subfamily has undergone extensive gene duplication. The Arabidopsis and Oryza genomes contain 13 and 16 Tau GSTs, respectively [ 2 , 3 ]. They are primarily responsible for herbicide detoxification together with class Tau GSTs, showing class specificity in substrate preference. Phi enzymes are highly reactive toward chloroacetanilide and thiocarbamate herbicides [ 4 ]. Some Phi GSTs have other functions including transport of flavonoid pigments to the vacuole and shoot regeneration [ 5 , 6 ].

GSTs are cytosolic dimeric proteins involved in cellular detoxification by catalyzing the conjugation of glutathione (GSH) with a wide range of endogenous and xenobiotic alkylating agents, including carcinogens, therapeutic drugs, environmental toxins, and products of oxidative stress. The GST fold contains an N-terminal thioredoxin-fold domain and a C-terminal alpha helical domain, with an active site located in a cleft between the two domains. GSH binds to the N-terminal domain while the hydrophobic substrate occupies a pocket in the C-terminal domain [ 6 ].

1. The poplar Phi class glutathione transferase: expression, activity and structure of GSTF1. Front Plant Sci 5, 712
2. Plant glutathione transferases. Meth. Enzymol. 401, 169-86
3. Plant glutathione transferases. Genome Biol. 3, REVIEWS3004
4. Cloning, sequencing, crystallization and X-ray structure of glutathione S-transferase-III from Zea mays var. mutin: a leading enzyme in detoxification of maize herbicides. J. Mol. Biol. 274, 577-87
5. THE FUNCTIONS AND REGULATION OF GLUTATHIONE S-TRANSFERASES IN PLANTS. Annu. Rev. Plant Physiol. Plant Mol. Biol. 47, 127-158
6. Structure, function and evolution of glutathione transferases: implications for classification of non-mammalian members of an ancient enzyme superfamily. Biochem. J. 360, 1-16