The poplar Phi class glutathione transferase: expression, activity and structure of GSTF1

摘要: Glutathione transferases (GSTs) constitute a superfamily of enzymes with essential roles in cellular detoxification and secondary metabolism plants as other organisms. Several plant GSTs, including those the Phi class (GSTFs), require conserved catalytic serine residue to perform glutathione (GSH)-conjugation reactions. Genomic analyses revealed that terrestrial have around ten GSTFs, eight Populus trichocarpa genome, but their physiological functions substrates are mostly unknown. Transcript expression showed predominant all genes both reproductive (female flowers, fruits, floral buds) vegetative organs (leaves, petioles). Here, we show recombinant poplar GSTF1 (PttGSTF1) possesses peroxidase activity toward cumene hydroperoxide GSH-conjugation model such 2,4-dinitrochlorobenzene, benzyl phenetyl isothiocyanate, 4-nitrophenyl butyrate 4-hydroxy-2-nonenal interestingly not on previously identified GSTF-class substrates. In accordance analytical gel filtration data, crystal structure PttGSTF1 canonical dimeric organization bound GSH or 2-(N-morpholino)ethanesulfonic acid molecules. The these protein-substrate complexes allowed delineating residues contributing G H sites form active site cavity. sum, presence transcripts proteins most especially rich metabolites flowers together its documented stress-responsive suggest function is associated transformation and/or peroxide removal rather than ligandin properties reported for GSTFs.